This paper presents a full pre-industrial prototype implementation of an innovative system capable to
detects vehicles and classify them. This work study the architecture of a full autonomous road sensor
network that count and classify passing vehicles, reducing the impact of conventional wired systems in
roads, by dramatically reducing their installation and operational costs. The power supply can be supported
either by solar harvest or by none rechargeable batteries. For communications the IEEE 802.15.4 with
ZigBee on top are used to transmit digitalized vehicle’s magnetic analogue signatures up to a vehicles
classification server. This information is acquired using a magnetometer translating in voltage the variation
of the natural magnetic field of the earth caused by ferromagnetic components of a vehicle passing over the
sensor. Results show clearly that it is possible to distinguish vehicles magnetic signatures per model and
class even at different speeds.
This paper presents a real-time emulator of a dual permanent magnet synchronous motor (PMSM) drive implemented on a field-programmable gate array (FPGA) board for supervision and observation purposes. In order to increase the reliability of the drive, a sensorless speed control method is proposed. This method allows replacing the physical sensor while guaranteeing a satisfactory operation even in faulty conditions. The novelty of the proposed approach consists of an FPGA implementation of an emulator to control the actual system. Hence, this emulator operates in real-time with actual system control in healthy or faulty mode. It gives an observation of the speed rotation in case of fault for the sake of continuity of service. The observation of the rotor position and the speed are achieved using the dSPACE DS52030D digital platform with a digital signal processor (DSP) associated with a Xilinx FPGA.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
Recently, LCL has become amongst the most attractive filter used for grid-connected flyback inverters. Nonetheless, the switching of power devices in the inverter configuration creates harmonics that affect the end application behavior and might shorten its lifetime. Furthermore, the resonance frequencies produced by the LCL network contribute to the system instability. This paper proposes a step-by-step guide to designing an LCL filter by considering several key aspects such as the resonance frequency and maximum current ripple. A single-phase grid-connected flyback microinverter with an LCL filter was designed then constructed in the MATLAB/Simulink environment. Several different parameter variations and damping solutions were used to analyze the performance of the circuit. The simulation result shows a promising total harmonic distortion (THD) value below 5% and harmonic suppression up to 14%.
The hardware implementation of sensorless brushless direct current motor drive incorporating H-infinity control strategy with optimized weights by particle swarm optimization in the speed control is carried out in this work. The methodology involved in the design of brushless direct current (BLDC) motor control with sensorless position detection technique, the design of H-infinity speed controller, steps involved in particle swarm optimization for optimizing coefficients of its weights and the hardware implementation is discussed in detail in this paper. Texas Instruments microcontroller board C2000 Delfino Launchpad LAUNCHXL F28377S and driver BOOSTXL DRV8301 are used for realization of the speed controller. The code is developed using C2000 hardware support package in MATLAB/SIMULINK platform. A comprehensive performance analysis is accomplished during starting of the motor and during the fast application and removal of load. This strategy is found to be robust resulting in faster load disturbance rejection and better reference speed tracking. The experimental results of the proposed strategy are compared with that of conventional proportional-integral (PI) controller. The time domain parameters are also compared. It is found that the proposed strategy exhibits better performance characteristics during transients and sudden disturbances in load.
Transmission lines react to an unexpected increase in power, and if these power changes are not controlled, some lines will become overloaded on certain routes. Flexible alternating current transmission system (FACTS) devices can change the voltage range and phase angle and thus control the power flow. This paper presents suitable mathematical modeling of FACTS
devices including static var compensator (SVC) as a parallel compensator and high voltage direct current (HVDC) bonding. A comprehensive modeling of SVC and HVDC bonding in the form of simultaneous applications for power flow is also performed, and the effects of compensations are compared. The comprehensive model obtained was implemented on the 5-bus test system in MATLAB software using the Newton-Raphson method, revealed that generators have to produce more power. Also, the addition of these devices stabilizes the voltage and controls active and reactive power in the network.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
This paper presents a real-time emulator of a dual permanent magnet synchronous motor (PMSM) drive implemented on a field-programmable gate array (FPGA) board for supervision and observation purposes. In order to increase the reliability of the drive, a sensorless speed control method is proposed. This method allows replacing the physical sensor while guaranteeing a satisfactory operation even in faulty conditions. The novelty of the proposed approach consists of an FPGA implementation of an emulator to control the actual system. Hence, this emulator operates in real-time with actual system control in healthy or faulty mode. It gives an observation of the speed rotation in case of fault for the sake of continuity of service. The observation of the rotor position and the speed are achieved using the dSPACE DS52030D digital platform with a digital signal processor (DSP) associated with a Xilinx FPGA.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
Recently, LCL has become amongst the most attractive filter used for grid-connected flyback inverters. Nonetheless, the switching of power devices in the inverter configuration creates harmonics that affect the end application behavior and might shorten its lifetime. Furthermore, the resonance frequencies produced by the LCL network contribute to the system instability. This paper proposes a step-by-step guide to designing an LCL filter by considering several key aspects such as the resonance frequency and maximum current ripple. A single-phase grid-connected flyback microinverter with an LCL filter was designed then constructed in the MATLAB/Simulink environment. Several different parameter variations and damping solutions were used to analyze the performance of the circuit. The simulation result shows a promising total harmonic distortion (THD) value below 5% and harmonic suppression up to 14%.
The hardware implementation of sensorless brushless direct current motor drive incorporating H-infinity control strategy with optimized weights by particle swarm optimization in the speed control is carried out in this work. The methodology involved in the design of brushless direct current (BLDC) motor control with sensorless position detection technique, the design of H-infinity speed controller, steps involved in particle swarm optimization for optimizing coefficients of its weights and the hardware implementation is discussed in detail in this paper. Texas Instruments microcontroller board C2000 Delfino Launchpad LAUNCHXL F28377S and driver BOOSTXL DRV8301 are used for realization of the speed controller. The code is developed using C2000 hardware support package in MATLAB/SIMULINK platform. A comprehensive performance analysis is accomplished during starting of the motor and during the fast application and removal of load. This strategy is found to be robust resulting in faster load disturbance rejection and better reference speed tracking. The experimental results of the proposed strategy are compared with that of conventional proportional-integral (PI) controller. The time domain parameters are also compared. It is found that the proposed strategy exhibits better performance characteristics during transients and sudden disturbances in load.
Transmission lines react to an unexpected increase in power, and if these power changes are not controlled, some lines will become overloaded on certain routes. Flexible alternating current transmission system (FACTS) devices can change the voltage range and phase angle and thus control the power flow. This paper presents suitable mathematical modeling of FACTS
devices including static var compensator (SVC) as a parallel compensator and high voltage direct current (HVDC) bonding. A comprehensive modeling of SVC and HVDC bonding in the form of simultaneous applications for power flow is also performed, and the effects of compensations are compared. The comprehensive model obtained was implemented on the 5-bus test system in MATLAB software using the Newton-Raphson method, revealed that generators have to produce more power. Also, the addition of these devices stabilizes the voltage and controls active and reactive power in the network.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
Mainly the DC motors are employed in most of the application. The main objective is to Regulate the DC motor system. A motor which displays the appearances of a DC motor but there is no commutator and brushes is called as brushless DC motor. These motors are widespread to their compensations than other motors in relationships of dependability, sound, efficiency, preliminary torque and longevity. To achieve the operation more reliable and less noisy, brushless dc motors are employed. In the proposed work, dissimilar methods of speed control are analysed. In real time submission of speed control of BLDC motor, numerous strategies are executed for the speed control singularity. The modified approaches are the employment of PI controller, use of PID controller and proposed current controller.
With the dominating utility of the internet, it becomes critical to manage the efficiency and reliability of telecom and datacenter, as the power consumption of the involved equipment also increases. Much power being wasted through the power conversion stages by converting AC voltage to DC voltage and then stepping down to lower voltages to connect to information and communication technology (ICT) equipment. 48/12 VDC is the standard DC bus architecture to serve the end utility equipment. This voltage level is further processed to multiple lower voltages to power up the internal auxiliary circuits. Power losses are involved when it is converted from higher voltage to lower voltages. Therefore, the efficiency of power conversion is lower. There is a need to increase the efficiency by minimizing the power losses which occur due to the conversion stages. Different methods are available to increase the efficiency of a system by optimizing the converter topologies, semiconductor materials and control methods. There is another possibility of increasing the efficiency by changing the architecture of a system by increasing the DC bus voltage to higher voltages to optimize the losses. This paper presents a review of available high voltage options for telecom power distribution and developments, implementations and challenges across the world.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
This paper presents an online efficiency optimization method for the interior permanent magnet synchronous motor (IPMSM) drive system in an electric vehicle (EV). The proposed method considers accurately the total system losses including fundamental copper and iron losses, harmonic copper and iron losses, magnet loss, and inverter losses. Therefore, it has the capability to always guarantee maximum efficiency control. A highly trusted machine model is built using finite element analysis (FEA). This model considers accurately the magnetic saturation, spatial harmonics, and iron loss effect. The overall system efficiency is estimated online based on the accurate determination of system loss, and then the optimum current angle is defined online for the maximum efficiency per ampere (MEPA) control. A series of results is conducted to show the effectiveness and fidelity of proposed method. The results show the superior performance of proposed method over the conventional offline efficiency optimization methods.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Effect of fiber and solenoid variation parameters on the elements of a correc...IJECEIAES
Controlling the polarization of the light output from single-mode fiber systems is very important for connecting it to polarization-dependent integrated optical circuits, while applications using a heterodyne detection system. Polarization controller using fiber squeezer is attractive for a lowloss, low-penalty coherent optical fiber trunk system. However, for polarization controllers using electromagnetic fiber squeezer, the stability problem due to the saturation of their magnetic circuit must be studied. In fact, in their conventional configuration, open-loop stability affects performance and limits applications. First at all, this effect has been analyzed and a feedback circuit with correctors has been proposed to improve stability performance. Then a simulation study is proposed to examine the influence of the system parameters on the corrector constants. The results of the simulation show that if the system parameters change the constants Kp, Ki and Kd of the PID corrector must be adjusted to keep an optimized dynamic response.
The emerging of inductive wireless power transfer (IWPT) technology provides more opportunities for the electric vehicle (EV) battery to have a better recharging process. With the development of IWPT technology, various way of wireless charging of the EV battery is proposed in order to find the best solution. To further understand the fundamentals of the IWPT system itself, an ample review is done. There are different ways of EV charging which are static charging (wired), static wireless charging (SWC) and dynamic wireless charging (DWC). The review starts with a brief comparison of static charging, SWC and DWC. Then, in detailed discussion on the fundamental concepts, related laws and equations that govern the IWPT principle are also included. In this review, the focus is more on the DWC with a little discussion on static charging and SWC to ensure in-depth understanding before one can do further research about the EV charging process. The in-depth perception regarding the development of DWC is elaborated together with the system architecture of the IWPT and DWC system and the different track versions of DWC, which is installable to the road lane.
This paper presents simulation and experimental results of anti-windup PI controller to improve induction machine speed control based on direct torque control (DTC) strategy. Problems like rollover can arise in conventional PI controller due to saturation effect. In order to avoid such problems anti-windup PI controller is presented. This controller is simple for implementation in practice. The proposed anti-windup PI controller demonstrates better dynamic step changes response in speed in terms of overshoots. All simulation work was done using Simulink in the MATLAB software. The experimental results were obtained by practical implementation on a dSPACE 1104 board for a 1.5 KW induction machine. Simulation and experimental results have proven a good performance and verified the validity of the presented control strategy.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
Stand-alone applications of Photovoltaic (PV) can be found in water pumping systems for rural area. The proper electric motor must be chosen for optimal considerations. One of the modern electric motor called brushless motor (BLDC) can be an alternative for this application although it has complexity in control. Powering such a motor by using electric energy generating by PV modules will be an interesting problem. In this paper, a PV powered BLDC motor system is proposed. The PV modules must produce maximum power at any instant time and then this power must be able to rotate the motor. By combining sequential stator energizing due to a rotor detection and a PWM concept, the speed of BLDC can be controlled. Meanwhile, to get maximum power of PV modules, detection of voltage and current of the modules are required to be calculated. Digital Signal Control (DSC) is implemented to handle this control strategy and locks the width of the PWM signal to maintain the PV modules under maximum power operation. The effectiveness of the proposed system has been verified by simulation works. Finally the experimental works were done to validate.
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
An improved luo converter for high power applicationseSAT Journals
Abstract
Power conversion is one of the major requirements in various industries and in daily life. Among various types of power
conversion, DC-DC conversion has greater importance. DC-DC conversion can be reliably performed using luo converter. It
employs voltage lift technique so that output voltage is increased stage by stage, in arithmetic progression. Luo converter can be
incorporated with the Z network or impedance network so as to ensure simple start up and smooth power conversion. An
impedance network consist of two identical inductors and two identical capacitors connected in ‘X’ shape. Besides power
conversion it also offers filtering operation. The luo converter in this scheme is of switched capacitor type. It helps to provide
regulated output voltage from an unregulated source of power supply. The major benefits of this proposed scheme is that it
combines the advantages of the switched capacitor, voltage lift technique and the impedance network. Hence the proposed scheme
has various advantages such as high power density, larger range of output DC voltage, lower or no inrush current, lower
harmonic injection, simple circuit, high voltage transfer gain, can process upto several tens of watts of power. The simulation
analysis and the hardware implementation shows that the output voltage obtained is higher than the expected theoretical value.
i.e, it is the highly boosted voltage output.
Keywords: Z-network, boost voltage, voltage lift technique
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
In industrial electric drive systems, it is common to find objects that need to solve the problem of angular position control, moving the object from one position to another asymptotically with no over-correction and guarantee. calculation of maximum fast impact. This is a multi-target optimization problem with many different solutions. This paper presents a method of constructing a PMSM motor position controller with a variable structure using dSPACE 1104 card. The system consists of a position control loop with a variable structure that is an outer loop and a speed control loop degree is the inner loop. In which, the speed adjustment loop uses adaptive law to compensate for uncertain functions and build a sliding mode observation to estimate load torque, friction and noise. The results of the simulation study were verified on Matlab-Simulink environment and experimented on dSPACE 1104 card to check the correctness of the built controller algorithm. The research results in the paper are the basis for the evaluation and setting up of control algorithms, design of electric drive systems in industry and the military.
Differential equation fault location algorithm with harmonic effects in power...TELKOMNIKA JOURNAL
About 80% of faults in the power system distribution are earth faults. Studies to find effective methods to identify and locate faults in distribution networks are still relevant, in addition to the presence of harmonic signals that distort waves and create deviations in the power system that can cause many problems to the protection relay. This study focuses on a single line-to-ground (SLG) fault location algorithm in a power system distribution network based on fundamental frequency measured using the differential equation method. The developed algorithm considers the presence of harmonics components in the simulation network. In this study, several filters were tested to obtain the lowest fault location error to reduce the effect of harmonic components on the developed fault location algorithm. The network model is simulated using the alternate transients program (ATP)Draw simulation program. Several fault scenarios have been implemented during the simulation, such as fault resistance, fault distance, and fault inception angle. The final results show that the proposed algorithm can estimate the fault distance successfully with an acceptable fault location error. Based on the simulation results, the differential equation continuous wavelet technique (CWT) filter-based algorithm produced an accurate fault location result with a mean average error (MAE) of less than 5%.
Design and manufacturing of iris waveguide filters for satellite communicationTELKOMNIKA JOURNAL
We propose in this paper, two bandpass filters in waveguide technology having rectangular symmetrical discontinuities with a half-radius r, designed and operating respectively in the X-Band (9-11.5) GHz and C-Band (3.5-5.5) GHz. These filters consists of eight irises placed symmetrically respectively on standard rectangular waveguides WR90 and WR229 in which resonant irises are inserted. These irises are used to couple the sections very strongly in this filter, which allows the bandwidth to be increased and the matching to be controlled. The comparison between the numerical and electromagnetic results, which we obtained for the filters, constitutes a means of validation of computer simulation technology (CST) environment and Mician for the design of the other circuit elements in the various frequency bands. We observed excellent consistency between the simulation curves and those of the measurements. The results obtained are promising and pave the way for the use of these structures in the fields of telecommunications.
Mainly the DC motors are employed in most of the application. The main objective is to Regulate the DC motor system. A motor which displays the appearances of a DC motor but there is no commutator and brushes is called as brushless DC motor. These motors are widespread to their compensations than other motors in relationships of dependability, sound, efficiency, preliminary torque and longevity. To achieve the operation more reliable and less noisy, brushless dc motors are employed. In the proposed work, dissimilar methods of speed control are analysed. In real time submission of speed control of BLDC motor, numerous strategies are executed for the speed control singularity. The modified approaches are the employment of PI controller, use of PID controller and proposed current controller.
With the dominating utility of the internet, it becomes critical to manage the efficiency and reliability of telecom and datacenter, as the power consumption of the involved equipment also increases. Much power being wasted through the power conversion stages by converting AC voltage to DC voltage and then stepping down to lower voltages to connect to information and communication technology (ICT) equipment. 48/12 VDC is the standard DC bus architecture to serve the end utility equipment. This voltage level is further processed to multiple lower voltages to power up the internal auxiliary circuits. Power losses are involved when it is converted from higher voltage to lower voltages. Therefore, the efficiency of power conversion is lower. There is a need to increase the efficiency by minimizing the power losses which occur due to the conversion stages. Different methods are available to increase the efficiency of a system by optimizing the converter topologies, semiconductor materials and control methods. There is another possibility of increasing the efficiency by changing the architecture of a system by increasing the DC bus voltage to higher voltages to optimize the losses. This paper presents a review of available high voltage options for telecom power distribution and developments, implementations and challenges across the world.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.
These slides presents an overall discussion on fault location techniques generally used in present power transmission and distribution system. Later of the class we will discuss about the implementation principles and mathematical formulations.
This paper presents an online efficiency optimization method for the interior permanent magnet synchronous motor (IPMSM) drive system in an electric vehicle (EV). The proposed method considers accurately the total system losses including fundamental copper and iron losses, harmonic copper and iron losses, magnet loss, and inverter losses. Therefore, it has the capability to always guarantee maximum efficiency control. A highly trusted machine model is built using finite element analysis (FEA). This model considers accurately the magnetic saturation, spatial harmonics, and iron loss effect. The overall system efficiency is estimated online based on the accurate determination of system loss, and then the optimum current angle is defined online for the maximum efficiency per ampere (MEPA) control. A series of results is conducted to show the effectiveness and fidelity of proposed method. The results show the superior performance of proposed method over the conventional offline efficiency optimization methods.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Effect of fiber and solenoid variation parameters on the elements of a correc...IJECEIAES
Controlling the polarization of the light output from single-mode fiber systems is very important for connecting it to polarization-dependent integrated optical circuits, while applications using a heterodyne detection system. Polarization controller using fiber squeezer is attractive for a lowloss, low-penalty coherent optical fiber trunk system. However, for polarization controllers using electromagnetic fiber squeezer, the stability problem due to the saturation of their magnetic circuit must be studied. In fact, in their conventional configuration, open-loop stability affects performance and limits applications. First at all, this effect has been analyzed and a feedback circuit with correctors has been proposed to improve stability performance. Then a simulation study is proposed to examine the influence of the system parameters on the corrector constants. The results of the simulation show that if the system parameters change the constants Kp, Ki and Kd of the PID corrector must be adjusted to keep an optimized dynamic response.
The emerging of inductive wireless power transfer (IWPT) technology provides more opportunities for the electric vehicle (EV) battery to have a better recharging process. With the development of IWPT technology, various way of wireless charging of the EV battery is proposed in order to find the best solution. To further understand the fundamentals of the IWPT system itself, an ample review is done. There are different ways of EV charging which are static charging (wired), static wireless charging (SWC) and dynamic wireless charging (DWC). The review starts with a brief comparison of static charging, SWC and DWC. Then, in detailed discussion on the fundamental concepts, related laws and equations that govern the IWPT principle are also included. In this review, the focus is more on the DWC with a little discussion on static charging and SWC to ensure in-depth understanding before one can do further research about the EV charging process. The in-depth perception regarding the development of DWC is elaborated together with the system architecture of the IWPT and DWC system and the different track versions of DWC, which is installable to the road lane.
This paper presents simulation and experimental results of anti-windup PI controller to improve induction machine speed control based on direct torque control (DTC) strategy. Problems like rollover can arise in conventional PI controller due to saturation effect. In order to avoid such problems anti-windup PI controller is presented. This controller is simple for implementation in practice. The proposed anti-windup PI controller demonstrates better dynamic step changes response in speed in terms of overshoots. All simulation work was done using Simulink in the MATLAB software. The experimental results were obtained by practical implementation on a dSPACE 1104 board for a 1.5 KW induction machine. Simulation and experimental results have proven a good performance and verified the validity of the presented control strategy.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
Stand-alone applications of Photovoltaic (PV) can be found in water pumping systems for rural area. The proper electric motor must be chosen for optimal considerations. One of the modern electric motor called brushless motor (BLDC) can be an alternative for this application although it has complexity in control. Powering such a motor by using electric energy generating by PV modules will be an interesting problem. In this paper, a PV powered BLDC motor system is proposed. The PV modules must produce maximum power at any instant time and then this power must be able to rotate the motor. By combining sequential stator energizing due to a rotor detection and a PWM concept, the speed of BLDC can be controlled. Meanwhile, to get maximum power of PV modules, detection of voltage and current of the modules are required to be calculated. Digital Signal Control (DSC) is implemented to handle this control strategy and locks the width of the PWM signal to maintain the PV modules under maximum power operation. The effectiveness of the proposed system has been verified by simulation works. Finally the experimental works were done to validate.
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
An improved luo converter for high power applicationseSAT Journals
Abstract
Power conversion is one of the major requirements in various industries and in daily life. Among various types of power
conversion, DC-DC conversion has greater importance. DC-DC conversion can be reliably performed using luo converter. It
employs voltage lift technique so that output voltage is increased stage by stage, in arithmetic progression. Luo converter can be
incorporated with the Z network or impedance network so as to ensure simple start up and smooth power conversion. An
impedance network consist of two identical inductors and two identical capacitors connected in ‘X’ shape. Besides power
conversion it also offers filtering operation. The luo converter in this scheme is of switched capacitor type. It helps to provide
regulated output voltage from an unregulated source of power supply. The major benefits of this proposed scheme is that it
combines the advantages of the switched capacitor, voltage lift technique and the impedance network. Hence the proposed scheme
has various advantages such as high power density, larger range of output DC voltage, lower or no inrush current, lower
harmonic injection, simple circuit, high voltage transfer gain, can process upto several tens of watts of power. The simulation
analysis and the hardware implementation shows that the output voltage obtained is higher than the expected theoretical value.
i.e, it is the highly boosted voltage output.
Keywords: Z-network, boost voltage, voltage lift technique
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
In industrial electric drive systems, it is common to find objects that need to solve the problem of angular position control, moving the object from one position to another asymptotically with no over-correction and guarantee. calculation of maximum fast impact. This is a multi-target optimization problem with many different solutions. This paper presents a method of constructing a PMSM motor position controller with a variable structure using dSPACE 1104 card. The system consists of a position control loop with a variable structure that is an outer loop and a speed control loop degree is the inner loop. In which, the speed adjustment loop uses adaptive law to compensate for uncertain functions and build a sliding mode observation to estimate load torque, friction and noise. The results of the simulation study were verified on Matlab-Simulink environment and experimented on dSPACE 1104 card to check the correctness of the built controller algorithm. The research results in the paper are the basis for the evaluation and setting up of control algorithms, design of electric drive systems in industry and the military.
Differential equation fault location algorithm with harmonic effects in power...TELKOMNIKA JOURNAL
About 80% of faults in the power system distribution are earth faults. Studies to find effective methods to identify and locate faults in distribution networks are still relevant, in addition to the presence of harmonic signals that distort waves and create deviations in the power system that can cause many problems to the protection relay. This study focuses on a single line-to-ground (SLG) fault location algorithm in a power system distribution network based on fundamental frequency measured using the differential equation method. The developed algorithm considers the presence of harmonics components in the simulation network. In this study, several filters were tested to obtain the lowest fault location error to reduce the effect of harmonic components on the developed fault location algorithm. The network model is simulated using the alternate transients program (ATP)Draw simulation program. Several fault scenarios have been implemented during the simulation, such as fault resistance, fault distance, and fault inception angle. The final results show that the proposed algorithm can estimate the fault distance successfully with an acceptable fault location error. Based on the simulation results, the differential equation continuous wavelet technique (CWT) filter-based algorithm produced an accurate fault location result with a mean average error (MAE) of less than 5%.
Design and manufacturing of iris waveguide filters for satellite communicationTELKOMNIKA JOURNAL
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Six-port Interferometer for W-band Transceivers: Design and CharacterizationIJECEIAES
The study has presented an extensive analysis of an integrated millimeter wave six-port interferometer, operating over a 10 GHz band, from 80 to 90 GHz. It has covered both semi-unlicensed point-to-point links (81-86 GHz), and imaging sensor system frequencies (above 85 GHz). An in-house process is used to fabricate miniaturized hybrid millimeter wave integrated circuits on a very thin ceramic substrate. Two-port S-parameter measurements are performed on a minimum number of circuits integrated on the same die, exploiting the circuit’s physical symmetry and chosen to collect enough data for full-port characterization. Based on these measurements on an integrated prototype, a six-port circuit computer model implemented and advanced system simulations performed for circuit analysis. Interferometer performances evaluated using several methods: analysis of harmonic balance, qi points’, homodyne quadrature demodulation, and error vector modulation (EVM). The analysis showed that this circuit can directly perform, without any calibration, the demodulation of various PSK and QAM signals over the 10 GHz band, with very good results.
A comprehensive fuzzy-based scheme for online detection of operational and t...IJECEIAES
Operational modes and topological changes affect power flow in the power systems. As a result, a broad spectrum of protection issues may happen in the power system. So, both the operational and topological changes should be detected fast to prevent blackouts. On the other hand, the existing detection schemes are complex in analyzing and implementation. Therefore, there is a need for an online scheme to identify the network's topology and operation mode simultaneously without complex computations and additional communication infrastructures. To this end, a comprehensive scheme is proposed in which the changes are detected by analyzing the power flow obtained from the network. For this purpose, line outage contingencies and operation modes are defined in rules to be used in a fuzzy inference system (FIS) as a decision-making tool. The proposed scheme can be implemented on existing lines as a communication infrastructure and determines the network’s status in an online manner. Also, in comparison to the existing schemes, the proposed scheme reduces the complexity and the computational burden. The proposed scheme is implemented on IEEE 8-bus system and the results proved its efficiency.
Miniature design of T-Shaped frequency Reconfigurable antenna for S-Band Appl...IJECEIAES
The article presents a miniature antenna with a simple geometry and a simple approach for reconfiguration. In order to make the T-shaped antenna frequency reconfigurable, we integrated Switches in specific positions. The location of the switches is determined following a study of the distribution of the surface currents of the suggested antenna. Indeed, we found that the insertion of switches in places where the concentrations of surface currents are high is irrelevant. In fact, to redirect current flow, the PIN diodes or RF Switch must be placed in positions where the distribution of the surface currents is of low concentration. These locations facilitate the establishment of new trajectories of the flux of current. As a result, a miniature tunable antenna dimension 20mm*20mm*1.6mm printed on FR4 substrate with 4.4 permittivity and with 0.04 loss tangent, the antenna can be adopted in many communication devices in view of its small size, its low manufacturing cost and performance on frequency sweep, the antenna operates in S-Band with an acceptable band and gain. The antenna is simulated and optimized using CST Microwave Studio.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Emc model for modern power electronic systems for harmonics, losses & emi...eSAT Journals
Abstract
Electromagnetic compatibility of power electronic systems becomes an engineering discipline and it should be considered at the
beginning stage of a design. Thus, a power electronics design becomes more complex and challenging and it requires a good
communication between EMI and Power electronics experts. Three major issues in designing a power electronic system are Losses,
EMI and Harmonics. These issues affect system cost, size, efficiency and quality and it is a tradeoff between these factors when we
design a power converter, filter. In this paper the EMC model is discussed which should be considered while designing the power
electronics systems. The design considerations in this paper help us to remove losses, harmonics & EMI elimination and power
quality improvement of Power systems.
Index Terms: Converter, EMI, EMC, Filter, Harmonics
Optimization of Empirical Modelling of Advanced Highly Strained In 0.7 Ga 0.3...IJECEIAES
An optimized empirical modelling for a 0.25µm gate length of highly strained channel of an InP-based pseudomorphic high electron mobility transistor (pHEMT) using InGaAs–InAlAs material systems is presented. An accurate procedure for extraction is described and tested using the pHEMT measured dataset of I-V characteristics and related multi-bias s-parameters over 20GHz frequency range. The extraction of linear and nonlinear parameters from the small signal and large signal pHEMT equivalent model are performed in ADS. The optimized DC and S-parameter model for the pHEMT device provides a basis for active device selection in the MMIC low noise amplifier circuit designs.
Fault location and correction are important in case of any power systems. This process has to be prompt and accurate so that system reliability can be improved , outage time can be reduced and restoration of system from fault can be accelerated.
Fault location calculation using Magnetoresistance sensor is described here.
The Octavia range embodies the design trend of the Škoda brand: a fusion of
aesthetics, safety and practicality. Whether you see the car as a whole or step
closer and explore its unique features, the Octavia range radiates with the
harmony of functionality and emotion
Comprehensive program for Agricultural Finance, the Automotive Sector, and Empowerment . We will define the full scope and provide a detailed two-week plan for identifying strategic partners in each area within Limpopo, including target areas.:
1. Agricultural : Supporting Primary and Secondary Agriculture
• Scope: Provide support solutions to enhance agricultural productivity and sustainability.
• Target Areas: Polokwane, Tzaneen, Thohoyandou, Makhado, and Giyani.
2. Automotive Sector: Partnerships with Mechanics and Panel Beater Shops
• Scope: Develop collaborations with automotive service providers to improve service quality and business operations.
• Target Areas: Polokwane, Lephalale, Mokopane, Phalaborwa, and Bela-Bela.
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• Scope: Provide business support support and training to women-owned businesses, promoting economic inclusion.
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3. Sectors : Agriculture ( primary and secondary) and Automative
Women and Youth are encouraged to apply even if you don't fall in those sectors.
Things to remember while upgrading the brakes of your carjennifermiller8137
Upgrading the brakes of your car? Keep these things in mind before doing so. Additionally, start using an OBD 2 GPS tracker so that you never miss a vehicle maintenance appointment. On top of this, a car GPS tracker will also let you master good driving habits that will let you increase the operational life of your car’s brakes.
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Experiencing a "Key Not Detected" problem in your Mercedes? Don’t take it for granted. Go through this presentation to find out the exact nature of the issue you are dealing with. Have your vehicle checked by a certified professional if necessary.
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Your VW's camshaft position sensor is crucial for engine performance. Signs of failure include engine misfires, difficulty starting, stalling at low speeds, reduced fuel efficiency, and the check engine light. Prompt inspection and replacement can prevent further damage and keep your VW running smoothly.
𝘼𝙣𝙩𝙞𝙦𝙪𝙚 𝙋𝙡𝙖𝙨𝙩𝙞𝙘 𝙏𝙧𝙖𝙙𝙚𝙧𝙨 𝙞𝙨 𝙫𝙚𝙧𝙮 𝙛𝙖𝙢𝙤𝙪𝙨 𝙛𝙤𝙧 𝙢𝙖𝙣𝙪𝙛𝙖𝙘𝙩𝙪𝙧𝙞𝙣𝙜 𝙩𝙝𝙚𝙞𝙧 𝙥𝙧𝙤𝙙𝙪𝙘𝙩𝙨. 𝙒𝙚 𝙝𝙖𝙫𝙚 𝙖𝙡𝙡 𝙩𝙝𝙚 𝙥𝙡𝙖𝙨𝙩𝙞𝙘 𝙜𝙧𝙖𝙣𝙪𝙡𝙚𝙨 𝙪𝙨𝙚𝙙 𝙞𝙣 𝙖𝙪𝙩𝙤𝙢𝙤𝙩𝙞𝙫𝙚 𝙖𝙣𝙙 𝙖𝙪𝙩𝙤 𝙥𝙖𝙧𝙩𝙨 𝙖𝙣𝙙 𝙖𝙡𝙡 𝙩𝙝𝙚 𝙛𝙖𝙢𝙤𝙪𝙨 𝙘𝙤𝙢𝙥𝙖𝙣𝙞𝙚𝙨 𝙗𝙪𝙮 𝙩𝙝𝙚 𝙜𝙧𝙖𝙣𝙪𝙡𝙚𝙨 𝙛𝙧𝙤𝙢 𝙪𝙨.
Over the 10 years, we have gained a strong foothold in the market due to our range's high quality, competitive prices, and time-lined delivery schedules.
Fleet management these days is next to impossible without connected vehicle solutions. Why? Well, fleet trackers and accompanying connected vehicle management solutions tend to offer quite a few hard-to-ignore benefits to fleet managers and businesses alike. Let’s check them out!
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Cetc11 - Wireless Magnetic Based Sensor System For Vehicles Classification
1. Wireless Magnetic Based Sensor System
For Vehicles Classification
P. Ghislain(1)
, D. Carona(1)
, A. Serrador(1)
, P. Jorge(1)
, P. Ferreira(1)
, J. Lopes(2)
(1) Instituto Superior de Engenharia de Lisboa, Lisbon, Portugal,
(2)Brisa Inovação e Tecnologia, Lisbon, Portugal
35945@alunos.isel.pt, {dcarona, aserrador, pjorge, pferreira}@deetc.isel.ipl.pt, jlopes@brisa.pt
Keywords: Smart Road Sensor, Magnetometer, ZigBee, Vehicles Classification.
Abstract: This paper presents a full pre-industrial prototype implementation of an innovative system capable to
detects vehicles and classify them. This work study the architecture of a full autonomous road sensor
network that count and classify passing vehicles, reducing the impact of conventional wired systems in
roads, by dramatically reducing their installation and operational costs. The power supply can be supported
either by solar harvest or by none rechargeable batteries. For communications the IEEE 802.15.4 with
ZigBee on top are used to transmit digitalized vehicle’s magnetic analogue signatures up to a vehicles
classification server. This information is acquired using a magnetometer translating in voltage the variation
of the natural magnetic field of the earth caused by ferromagnetic components of a vehicle passing over the
sensor. Results show clearly that it is possible to distinguish vehicles magnetic signatures per model and
class even at different speeds.
1 INTRODUCTION
With the growing number of vehicles travelling
on roads, the need of road traffic control and
monitoring also increases. The available
technologies includes inductive loop, video image
processing, weight-in-motion, pneumatic tube,
piezoelectric, ultrasonic, acoustic, infrared and
magnetic sensors. Inductive loops have high
installation and operation costs. Camera image
processing requires expensive specialized processor
unit per equipment and is sensible to weather
conditions. The piezoelectric systems use a
transversal tube on the road, subject to a rapid
deterioration and not effective for highways. The
others techniques have a smaller range of application
than magnetic sensors [1].
The sensor technology used in this study is the
Anisotropic Magnetic Resistance (AMR) with a
magnetic resolution of one part in ten thousand of
the Earth magnetic field [2]. With such a good
precision, it has been clear during the development
that the quality of the electronic design plays an
important role to retain this level of precision. For
this application the Earth magnetic field has an
important advantage on previous magnetic
technologies: its presence anywhere on Earth.
Inductive loop requires the production of an artificial
magnetic field with significant energy consumption
and the connection of an external power supply. The
natural magnetic field may vary from 0.2 to 0.7
Gauss and its lines of forces are not horizontal but
oblique, changing place to place in strength and
inclination. The intensity of this field can vary with
the weather and the season. It has not the stability
neither the accuracy of the artificial inductive loop
[3]. This variability is a challenge that must solve
the developed device.
This prototype transmits data using a low bitrate
wireless communications with low energy
consumption. The sensor cost, installation and
operation of the proposed road sensor network is
expected to be much lower compared with the
inductive loop systems solutions. The control centre
that processes the vehicles magnetic signatures is a
fundamental sub-system in road management to
identify traffic load per vehicles
behaviour/profiles/classes. Figure 1, show the
laboratory prototype.
2. Figure 1: Developed Prototype.
The research work developed by ISEL laboratory in
vehicle classification methods based on many Smart
Road Sensors technologies [4][5][6] contributes to
the knowledge needed in some aspects of the work
presented. The study of magnetic sensor is a natural
development of this strategy. Works of other
research centres have been studied in order to gain
knowhow.[7][8][9].
To describe the work in more detail, this paper is
structured as follows: in Section 2, the system
architecture and each component implementation
overview is provided, in Section 3 results of the
performed tests are presented, while in Section 4
conclusions and future work are summarised.
2 ARCHITECTURE
The system architecture proposes for vehicle count
and classification the insertion of one sensor in the
centre of each motorway lane. On the road side, the
access point collects data from the sensors and
relays them to the WAN network of the road
operator via GPRS/3G or fixed network. The control
centre receives the sensor signature and processes it
in real time. Then an information system displays
the traffic load for each installed road sensor and
gives access to a statistical distribution of the
detected vehicle’s class.
The low cost of each detection point allows a
higher density of these road sensors and a much
better visualization of the traffic load.
Figure 2: System Architecture Overview.
The installation of the access point close to sensors
(Figure 2) decreases the wireless transmission power
to the lowest possible value, extending the sensor
battery live time.
2.1 Magnetometer
The selection criteria for the magnetic sensors for
this work were based on a set of principles:
sensitivity to the Earth magnetic field variation
caused by a ferromagnetic objects, the energy
consumption and the financial sensor cost.
Another important selection criterion was the ability
to restore the sensibility of the sensor via included
coils and a Set/Reset operation that only one
supplier offers. We chose the B component [2].
Reference A B C
Supply [V] 5-12 5-25 1.8-25
Current [mA] 10 5 1
Set/Reset Current [A] 3 0.5 0.5
Sensibility [mV/V/Gauss] 3.2 1 1
Resolution [µGauss] 27 85 120
Table 1: Comparison between sensors.
The family of Anisotropic Magneto-Resistances
(AMR), allows to measure the Earth magnetic field
with a precision below 0.5%. This background field
is quite permanent, suffering only small and slow
changes. Thus, the sensor includes an auto-
calibration algorithm that adapts the measures so
that this reference can be considered stable during a
period of time well suited to vehicle detection.
Vehicles metallic characteristics produces
typically a flux variation around 50% of the Earth
magnetic field, but the variation can be many times
this value with vehicles built with reinforced iron
parts. In those rare cases, the magnetic signature will
be partially saturated but still distinctive and usable
for classification.
The project also wanted to determine the overall
parameters offered by the technology and two
orthogonal magneto sensitive axes where important
to study the relation between the orientation of
magnetic field and the vehicle’s movement [2].
Modern vehicles include many ferromagnetic
components as show into the representation in
Figure 3 [3], for example the wheels axels, motor
components, transmission, gas escape are made of
steel or iron. Electric motors and alternator creates a
magnetic field. All those components concentrate or
disperse the Earth magnetic field and thus, create
detectable variations at the output of the AMR
sensor.
3. Figure 3: Vehicle magnetic signature [3].
The resistive elements of the sensor are placed in
a Wheatstone Bridge shown in Figure 4 that allows
to compare two tensions coming from two resistive
dividers. Each resistive divider is made of two
branches which are composed of 6 Permalloy
magneto-resistive elements oriented at 45º. Each
branch elements are positioned at 90º of their
companion branch elements. When a branch has
low magnetic resistance, its companion branch will
have a high one. Both dividers are in a mirrored
conformation and respond in an opposite way
allowing a maximum tension difference between
them.
Figure 4: Structure of the sensor [3].
Where Vb is the applied tension, in our case,
3.3V, Out+ and Out-, the tension of the two dividers
values Vb/2 when the magneto-resistance are equal,
therefore when there is no external magnetic field
applied. The output differential tension (Out+, Out-)
is equal to the ratio of the variation of the resistance
of one branch on the resistance of it, times the
applied tension Vb. It is a small voltage value of few
mV. On the influence of the Earth magnetic field, a
value of 0.5 Gauss creates a 2.5mV of differential
tension.
The magnetometer requires a correction of the bias
created by the local value of the magnetic field of
the Earth and an amplification of the differential
tension which gain should be between 500 and 2000.
Those values changes at each installation’s
location because the orientation of the main
magnetic sensor direction must be parallel to the
road traffic direction and therefore, the strength of
the Earth magnetic field is always different.
Two possibilities are available, the manual
configuration in place or the auto-calibration of the
sensor with a set of digital potentiometers. As the
Earth field can change on a long time scale, the
second option is a requirement for an industrial
solution.
2.2 Electronics components
The AMR sensor that provides a small tension
variation between two outputs must be followed by a
stage of OpAmps, operation amplifiers, that
provides a bias correction, a difference and an
amplification operation.
The 3 operations can be done in one circuit or
via many OpAmp in cascade, depending of
pretended level of precision. The signal is
conditioned to remain into the range of [0, VCC]
Volts, where VCC is the power supply voltage.
Those two tensions values are then redirect to a
microprocessor that can digitalize them, store the
data and after the end of the capture of a magnetic
signature, send it to the wireless radio
subcomponent.
The prospection of electronics components to
build a LR-WPAN, low rate wireless personal area
network, was limited essentially to the wireless
solution available for the ISM, Industrial Security
and Medical, band without licencing procedure.
The IEEE 802.15.4 compliant components offer
the better choice and we made a market research in
order to select a good and reliable solution. The
more advanced components offers a complete
System on a Chip solution, including a
microprocessor, a radio subcomponent and many
other features that target the component to specific
markets. The component that we choose accept the
digitalization of up to 8 analogue inputs, offer 8
Kbyes of RAM, um transceiver for 2.4 GHz IEEE
802.15.4 compliant, one OpAmp, two power
outputs[10]. It enables to shrink the sensor board and
its quality has been confirmed during the project.
2.3 ZigBee
To transmit wirelessly the collected information, the
IEEE 802.15.4 standard with ZigBee on top is
adopted because it was developed to operate in short
range communications and low power consumption
systems, supporting also high level networking
features.
4. Many protocols use IEEE 802.15.4 as their PHY
and datalink layer. WirelessHART, ISO110a,
ZigBee, 6loWPAN and a set of other proprietary
network layers.
ZigBee define in OSI, Open System
Interconnection, from the Network up to part of the
Application layer. In our work, we have not found a
specific ZigBee profile for sensors data capture
through the implementation of duty cycles; so, we
have developed a proprietary ZigBee profile and use
only the ZigBee Network layer.
Our communication features includes a
transport layer with data fragmentation, packet
resend, packet acknowledge if well received by the
ZigBee coordinator in the access point; the support
of many sensors for one coordinator and an
asynchronous serial gateway.
The coordinator firmware had also to be developed.
From what ZigBee Alliance announced and what
one could use without firmware development there
was a gap. This problem is attended through the set
of specifications that where launch since 2010 until
now by the ZigBee Alliance. Fabricants have
naturally a big problem with those specifications:
they require a lot of manpower to develop them and
the market look for very low cost solutions. For the
moment, those announced specifications are not
always available.
The ZigBee coordinator firmware that we have built,
suits for the project but is in a revision process to
adopt an architecture that allows the reception of
packet burst from ZigBee. A circular list of buffers
memorizes the incoming packets. The relay of them
is made asynchronously to the serial gateway. The
energy cost of the transfer of a signature is
maintained to the minimum with maximum speed.
The road sensor activates communications only
when it has data to send or after some seconds of
inaction. Data from the server and the access point
are access only at that moment.
The ZigBee stack is well suited for rapid
development project and has parameters that are
available to tune it to specific applications. The main
features that are offered are the automatic
association and re-association to the network
knowing that the coordinator chooses a channel that
is not known by the terminal equipment.
The ZigBee features used by the project are limited
and the use of the ZigBee stack is not mandatory.
Another Stack simpler and power saving, may be
proprietary, could also fit all the needs, without
license costs.
2.4 Orientation and attenuation
The orientation of the road sensor’s antenna
maximum radiate power should be in a quarter of
hemisphere in the direction of the road side as the
sensor is always oriented toward the vehicles
direction. Presently, it is plan to use an isotropic
ceramic antenna embedded into the cover of the road
sensor, allowing the coordinator installation
anywhere around. To increase radio link
performance it is recommended to use directional
antennas to support adverse weather like rain and
snow.
The coordinator must be oriented with a vertical
angle of a least 30º and must use a directive antenna.
For sharp angles the link attenuation rises quickly
because there is no line of sight between antennas.
In fact, the road sensor in located into a hole that is a
kind of wave guide and the isotropic radiation of the
ceramic antenna is affected and the majority of the
radiation goes vertically. Higher is the angle of the
coordinator, better is the reception.
The attenuation caused by the cover material has
taken our attention. We have made some attenuation
tests and determine that acrylic and glass could be
used for this application as well as asphalt which
present 1 dB/cm of attenuation. This is surprising
but asphalt is made of very long aliphatic chains and
is hydrophobic so the result is coherent with other
similar material like plastics. Modified asphalt with
the substitution of the gravel with adequate low
attenuation material can constitute a good cement to
embed the device into the road.
2.5 Power management
The sensor was designed to extend the battery live
time to the maximum, thus the device architecture is
modular and each part it is only active when strictly
necessary. The CPU remains always the master and
do not depend of external interrupt to wake-up. It is
the most convenient architecture and also the more
efficient. The CPU uses one output signal to suspend
the magnetometer and manage all internal functions.
The alternative architecture use an external
interrupt to wake-up the CPU, and to avoid the
appearance of an indeterminate state in which the
sensor would never wake-up, a more complex
electronic circuit is needed which increases the
power consumption and therefore this approach was
not taken into account.
The power management developed for the sensor
device is based on the electronic architecture and on
the firmware development.
When ZigBee do not communicate with the
network, no power is used to supply the radio
subcomponent. The road sensor wakes up
5. 92%
0%
20%
40%
60%
80%
100%
180 x 10 90 x 10 90 x 5 45 x 5 20 x 5
Energysavingratio
Maximal velocity x samples per vehicle meter
Normal
POWER_SAVING
periodically to check for incoming data or detect a
car, digitalize and send the magnetic signature and
check for incoming data. This optimization cut 75%
of the energy requirements of the SoC: from 32 mA
the consumption falls to 8 mA.
The ZigBee Stack provides elements to implement a
closed loop TX Power control but ZigBee don’t
implement it. Each received packet of 802.15.4
comes with a LQI, line quality indicator whish
calculus is based on the ED, Energy Detection, a
signal to noise parameter. The received LQI coming
from the coordinator is used by the road sensor to
manage dynamically the TX Power. This power
control is important to ensure the auto adaptation of
the road sensor to changing weather conditions
because heavy rains attenuate the radio signal and
require more TX power. And when weather
conditions turns better, the priority must be to
diminish TX power in order to minimize
transmission energy cost.
The link budget between the road sensor and the
coordinator must have an important power reserve.
ZigBee chip have a sensibility about 95 dBm. The
design of the antennas is essential to make a road
sensor system adaptable to any weather conditions:
traffic jam and accident happens during those
situations and the road sensor mission is to guaranty
full functioning state and information dispatch
without failures at that moment.
As the road sensor should only send data to the
right side of the motorway in right hand traffic
countries, the gain of its antenna can be better than 6
dBi which correspond to a quarter of hemisphere of
the isotropic antenna of 0 dBi. On the coordinator
side, it is very important to use an antenna with a
gain higher than 14 dBi, which is about a 60º BW,
Beam Wide at 3 dB. This combination offers more
than 20 dB total antennas gain that can constitute
part of the necessary power budget reserve. The
space diversity that some fabricants propose is
important if the application is sensible to multipath
but, for this open air application, few installations
may suffer from short distance attenuation due to the
lack of reflection of the transmitted signal.
In order to achieve better power saving, the
firmware has been compiled to activate the sleeping
mode automatic switching that ZigBee stack
provide. In the Figure 5, the Normal firmware shows
a power saving starting only with a low frequency
sampling. After an optimization of the firmware, we
compiled a version that processes much better this
switching and can achieve about 90% of saving,
switching from 8 mA without duty cycle to 0.7 mA.
Figure 5: Energy consumption with both firmware.
The research team believes that the firmware can be
still tuned to achieve better saving performance.
2.6 Power sources
With a power saving energy mode spending 0.7 mA,
this sensor represents a very low drain voltage
equipment enabling the use of none rechargeable
batteries. A set of 2x2 D Professional Long Duration
Alcaline Batteries offers a capacity of 33000 mAh at
2.2-3.3 V. The discharge per year is about 3% [11]
and this means about 4,94 years of useful life. A
lithium battery offers more than a 1.5 times the
capacity of an Alkaline and very low discharge
current. Lithium batteries are not stable when
exposed to temperatures higher than 60º C and
therefore should not be a first choice for a road
sensor in Portugal [12].
If the sensor architecture privilege precision and
3 directions orthogonal magnetic sensing, the energy
consumption is higher and the sensor must be
supplied by solar harvest power.
2.7 Power capture
To determine the size of the solar captor, it is
necessary to calculate the expectable energy power
received during the month and the place in Portugal
of lowest solar radiation. Hopefully, European
program PVGIS [13] provides this information for
any European Country, including Portugal.
After that, using a set of atenuation parameters,
our model gives a value of the minimum daily
average power that can be captured with
moncristaline or amorphous silicium cell. The ratio
of the necessary power on the capturable power per
m2
defines the minimal surface.
c
n
P
P
S
24
(1)
where,
Pc : is the daily average solar power per m2
available after the elimination of all
attenuations;
6. Pn : necessary power per hour for the sensor;
S : minimum surface for the solar captor in m2
.
This expression is expanded with the following
parameters:
cojindhdirtrcc
n
ffrRrRrP
P
S
))((
24
(2)
where,
Pr : daily average solar power radiation of the
location and month of lowest radiation in the
geographical area of installation;
rtrc : conversion percentage (1 minus losses)
accounting for temperature, reflection of the cell
surface and DC-DC conversion losses.
Typically 70%;
Rdir e Rind : percentage of direct and indirect
solar radiation, the sum of both equal 100%.
Used 50% for both. Use PVGIS estimation;
rh: conversion percentage due to the horizontal
position of the sensor. Used 72%;
rj: conversion percentage due to the window of
the sensor. Used 70%;
fo: osculation factor made by the passing vehicle
shadow. Used 92,5% ;
fc: conversion percentage of the solar cell. Used
15% and 8%;
For rh, the PVGIS provides an estimation that can be
used. The overall conversion performance is 5%
with monocrystalline Silicon and 2.7% with
amorphous cells.
The choice of a solar cell is facilitated by the
existence of DC-DC converters that accept low
voltage sources under 0.3 V, transform and regulate
an output tension of 3.3 or 5 V using charges pump
with an efficiency around 90% [14] and [15].
The MPP, Maximal Power Point, of the cell can be
obtained via a specific electronic circuit but the
efficiency is low for a single solar cell and a serial
load with the battery may be more effective and
simple.
For the rechargeable battery the horizon of 3
years maximum life expectancy is today a reality.
The use of super capacitors has been evaluated and it
is possible with one DC-DC converter at the output
extract about 80% of the capacity.
2.8 Firmware development
The selected component is a SoC that allows
inserting code into the processing of the ZigBee
stack. The firmware had to achieve a set of goals:
scan the magnetometer axis in the direction of
the traffic in order to detect passing vehicles,
start the scanning of the magnetic signature at a
rate that is adapted to an estimated speed in
order to minimize data size,
detects the end of the vehicle,
insert the start of curve data store in a circular
memory buffer,
adapts the rate of sampling from start to the first
vehicle’s axis,
send the data via ZigBee and finally
set/reset the magnetometer in order to maintain
its high anisotropy and magneto-resistance
sensitivity.
Maintenance processing of the road sensor includes:
the TX power management,
the control of the power of the magnetometer
and operational amplifiers,
auto calibrations and
Earth Magnetic Field detection.
The speed estimation (3) is made by the firmware
and based on the average distance between the start
of digitalisation and the first wheel of the car. As
each car model is different, this estimation will be
different among cars and trucks but it is expected to
always be similar for the same vehicle. This allows
having a reasonable and fixed amount of samples
per vehicle’s model, independent of the speed
capture. It is also a discriminant factor for the
pattern matching engine in the server and can help
the discovery of the car model.
t
d
Ves
(3)
Where:
Ves is the speed estimation;
d the distance between start and first axe;
Δt the duration of the between both;
The coordinator has been also a matter of attention
because the reception of packets depends of its
availability. The use of an input circular buffer list
waiting for the transmission on the serial gateway
was decisive for the coordinator radio reception
efficiency.
3 RESULTS
The first question to solve was the orientation of the
sensor. The reproducible effect on a magnetic axis is
achieved when the vehicle motion is in its direction.
This means that we do not orient the main magnetic
7. 0
0,5
1
1,5
2
2,5
3
0 20 40 60 80 100
MagnetometerYaxistension[V]
Samples
Signature
EMF
axis in the direction of the north magnetic pole that
would provide the best sensing amplitude, but
always in the traffic direction.
The parallel sensing direction, the 2nd
axe, has a
quite different measure of the Earth Magnetic Field
and its amplitude is different from the main axe. The
bias can be corrected via a supplementary OpAmp
for the calibration than the one of the main axis. If
the magnetic axes input signals are amplified with
different gain, it can be demonstrated that the vector
norm of the two orthogonal axes change if we turn
the sensor horizontally, for the same car. In other
word, using different gain on both magnetic axes can
produce different magnetic signature for the same
car when the road sensor is install in different
location. This must be ovoid in order to guaranty
information coherence. The 1-axes magnetometer
oriented in the direction of the traffic flux can
provide already much information, completely
coherent, with a much lower cost in processing and
energy.
Figure 6 and Figure 7 shows the forward
signature of a BMW and the parallel signature of the
same car.
Figure 6: Forward axis scanning.
Figure 7: Lateral axis scanning.
The tests on the algorithm that was designed
show a correct estimation of the Earth magnetic field
for both axes. The detection and scanning of the
magnetic signature is completed and well captured.
The vehicle count is therefore correct.
We verify that for a specific car model, at 20 up to
60 km/h, we receive about the same amount of fixed
samples validating the speed detection algorithm.
With other car model, we had the same result but
with a different number of samples for this car
model. Those results are encouraging because we
have still to turn better de definition of boundaries.
Figure 8: Main axis, vehicle at 20km/h.
Figure 9: Main axis, same vehicle at 40km/h.
Figure 10: Main axis, same vehicle at 60km/h
On the other hand, the variability of the curves
indicated that the signature has an important error
margin as it can be seen in the Figures 8 and 9.
We believe that a single axe magnetic sensor
correctly oriented in the flux traffic direction is
sufficient to characterize a vehicle model. We have
test with Van and others small cars and the magnetic
signature is very different car by car.
0 10 20 30 40 50
0
0,5
1
1,5
2
2,5
3
Samples
MagnetometerXaxistension[V]
0 10 20 30 40 50
0
0,5
1
1,5
2
2,5
3
Samples
MagnetometerXaxistension[V]
0 10 20 30 40 50
0
0,5
1
1,5
2
2,5
3
Samples
MagnetometerXaxistension[V]
8. The tuning of the parameters of our firmware
will allow defining an optimized set and achieving
easily a detection of vehicle classes as well as we
believe that the model detection is possible.
4 CONCLUSIONS
The firmware that has been developed process
well the magnetic signature capture and allow to
confirm that for each tested vehicle, there was a very
distinctive signature with however important
variation between successive tests for the same car.
The speed algorithm that we have developed
performs well and provides a discrimination factor
for the classification engine.
In our view, two sensors devices are possible: a
small sensor expect to measure 30 x 80 mm that
would only use one magnetometer axis and would
be powered by battery, with the advantage of having
a low cost production. It is expect, from the
consumption model and the test with
POWER_SAVING firmware, to achieve at least 5
years of permanent operation. The use of a special
asphalt cement to embed the sensor into the road is
also an option that is considered in order to turn very
simple, quick and cheap the insertion of the sensor
into the road.
Another sensor architecture proposed uses 3-
axes magnetometers and high precision
digitalization. It is expected to measure 125 x 80
mm. A solar cell would power the sensor with a
super capacitor to maintain the operation during the
worst month of the year in terms of solar radiation
power. Rechargeable batteries last only some years,
for this, we opt for super capacitors used at 80% of
the maximum charge voltage which provide about
10 years of live spanning. This sensor should be
inserted into a permanent chamber embed into the
road and be easily maintained, providing the best
precision available with this technology.
The next step of the research team will be the
study of the classification techniques.
ACKNOWLEDGEMENTS
Authors would like to thank Brisa Innovation
(Technological provider of the largest Portuguese
motorway operator), through the research and
development Smart Road Sensors project and to
ISEL’s research groups GIEST and M2A.
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