This document contains a question bank for energy managers and energy auditors related to energy efficient technologies in electrical systems. It includes 20 multiple choice questions about topics like maximum demand controllers, power factor correction capacitors, automatic power factor controllers, energy efficient motors, variable frequency drives, and more. It also includes short answer questions about maximum demand control, automatic power factor controllers, areas for improvement with energy efficient motors, technical aspects of energy efficient motors, soft starters, variable torque loads, variable frequency drives, and applications of variable frequency drive control for pumps and fans.
Modelling and Simulation of DC-Motor Electric Drive Control System with Varia...IDES Editor
This work represents a mathematical analysis and
simulation of dc-motor electric drive control system with
variable moment of inertia. A separately-excited dc motor is
used in this control system. A mathematical model for this
motor has been simulated and tested in Matlab/Simulink. A
closed-loop control system for this dc electric drive system is
proposed. The proposed control system is based on the
technical optimum method of design. The controlled variable
of this system is the load angular speed. In this control system
the moment of inertia is considered to be variable. It varies as
a function of time. A speed controller and a current controller
are designed for the suggested model to meet the desired
performance specifications by using the technical optimum
method. These controllers are attached to the control system
and the closed-loop response is observed by simulation and
testing this model. The results show the high-performance of
the designed control system.
Solar fed BLDC motor drive for mixer grinder using a buck-boost converterjournalBEEI
In existing mixer grinders, the universal motor is used due to its high starting torque than the induction motor. To achieve higher speed for smaller devices, the implementation of the universal motor becomes cheaper. The absence of brushes and the reduction of noise in the BLDC extends its lifetime, making it ideal for a mixer grinder. The solar-powered BLDC motor drive for a mixer grinder is presented in this paper. A DC-DC buck boost (BB) converter is utilised to operate the PV (photovoltaic) array at its highest power. The proposed hysteresis current (HC) control BLDC system is developed in the MATLAB. A comparison performance is demonstrated between the commercially available mixer grinder and the simulated proposed system.
This document describes a study on modeling and simulating a permanent magnet brushless DC (PMBLDC) motor drive system in MATLAB/Simulink. The authors develop a model of a PMBLDC motor with a 120-degree inverter system and implement closed-loop speed control using a PI controller. Simulation results confirm the validity of the model and controller. The paper examines the effects of load and inertia changes on the motor's speed performance.
IRJET- Speed Control of BLDC Motor using PID Tuned Fuzzy ControllerIRJET Journal
This document summarizes a study that used a PID-tuned fuzzy controller to control the speed of a brushless DC motor (BLDC) with varying load parameters like torque and current. A solar photovoltaic array charges a boost converter which supplies power to a voltage source inverter that provides electronic commutation for the BLDC motor. The PID-tuned fuzzy controller adjusts the gains of the PID controller based on the load range to maintain the desired motor speed. The system was simulated in MATLAB/Simulink.
IRJET- Dual Speed Control of Underwater Auxiliary Propulsion using BLDC M...IRJET Journal
This document discusses a proposed dual speed control system for the auxiliary propulsion of underwater vehicles using a brushless DC motor (BLDC). The existing system uses DC motors which have limitations that can be overcome by using a BLDC motor. The proposed system features a BLDC motor, current sensor, PID controller, and speed/direction sensor. It aims to provide two-speed bidirectional control of the auxiliary propellers through closed-loop control of the BLDC motor's speed using a PID controller. Simulation results are presented to validate that the proposed system can efficiently control the auxiliary propulsion at two speeds in both directions.
The document summarizes a study on improving the performance of a two-leg inverter fed brushless DC motor (BLDCM) drive. Key points:
1) A two-leg inverter fed BLDCM drive is proposed that uses only four switches and two current sensors, compared to a conventional three-leg inverter that uses six switches and three current sensors. This reduces switching losses and cost.
2) A MATLAB/Simulink model of the proposed two-leg inverter fed BLDCM drive with two DC input sources is developed.
3) Simulation results show the proposed drive has reduced torque ripple, lower voltage stress, lower current total harmonic distortion, and faster dynamic performance
This paper presents a control scheme for speed control system in brushless dc (BLDC) motor to be utilized for electric motorbike. While conventional motorbikes require engine and fuel, electric motorbikes require DC motor and battery pack in order to be powered up. The limitation with battery pack is that it will need to be recharged after a certain period and distance. As the recharging process is time consuming, a PID controller is designed to maintain the speed of the motor at its optimum state, thus ensuring a longer lasting battery time (until the next charge). The controller is designed to track variations of speed references and stabilizes the output speed accordingly. The simulation results conducted in MATLAB/SIMULINK® shows that the motor, equipped with the PID controller was able to track the reference speed in 7.8x10-2 milliseconds with no overshoot. The result shows optimistic possibility that the proposed controller can be used to maintain the speed of the motor at its optimum speed.
1) The document proposes a hybrid renewable energy system using a doubly fed induction generator (DFIG) driven by a wind turbine combined with photovoltaic (PV) panels.
2) A three-level neutral point clamped (NPC) inverter is used to convert the rectified voltage from the grid or DC voltage from the PV panels to a variable frequency voltage to supply the DFIG rotor.
3) Maximum power point tracking (MPPT) is used to extract maximum power from the PV panels and regulate the output voltage from the DFIG based on a vector control scheme using D-Q axis current control.
Modelling and Simulation of DC-Motor Electric Drive Control System with Varia...IDES Editor
This work represents a mathematical analysis and
simulation of dc-motor electric drive control system with
variable moment of inertia. A separately-excited dc motor is
used in this control system. A mathematical model for this
motor has been simulated and tested in Matlab/Simulink. A
closed-loop control system for this dc electric drive system is
proposed. The proposed control system is based on the
technical optimum method of design. The controlled variable
of this system is the load angular speed. In this control system
the moment of inertia is considered to be variable. It varies as
a function of time. A speed controller and a current controller
are designed for the suggested model to meet the desired
performance specifications by using the technical optimum
method. These controllers are attached to the control system
and the closed-loop response is observed by simulation and
testing this model. The results show the high-performance of
the designed control system.
Solar fed BLDC motor drive for mixer grinder using a buck-boost converterjournalBEEI
In existing mixer grinders, the universal motor is used due to its high starting torque than the induction motor. To achieve higher speed for smaller devices, the implementation of the universal motor becomes cheaper. The absence of brushes and the reduction of noise in the BLDC extends its lifetime, making it ideal for a mixer grinder. The solar-powered BLDC motor drive for a mixer grinder is presented in this paper. A DC-DC buck boost (BB) converter is utilised to operate the PV (photovoltaic) array at its highest power. The proposed hysteresis current (HC) control BLDC system is developed in the MATLAB. A comparison performance is demonstrated between the commercially available mixer grinder and the simulated proposed system.
This document describes a study on modeling and simulating a permanent magnet brushless DC (PMBLDC) motor drive system in MATLAB/Simulink. The authors develop a model of a PMBLDC motor with a 120-degree inverter system and implement closed-loop speed control using a PI controller. Simulation results confirm the validity of the model and controller. The paper examines the effects of load and inertia changes on the motor's speed performance.
IRJET- Speed Control of BLDC Motor using PID Tuned Fuzzy ControllerIRJET Journal
This document summarizes a study that used a PID-tuned fuzzy controller to control the speed of a brushless DC motor (BLDC) with varying load parameters like torque and current. A solar photovoltaic array charges a boost converter which supplies power to a voltage source inverter that provides electronic commutation for the BLDC motor. The PID-tuned fuzzy controller adjusts the gains of the PID controller based on the load range to maintain the desired motor speed. The system was simulated in MATLAB/Simulink.
IRJET- Dual Speed Control of Underwater Auxiliary Propulsion using BLDC M...IRJET Journal
This document discusses a proposed dual speed control system for the auxiliary propulsion of underwater vehicles using a brushless DC motor (BLDC). The existing system uses DC motors which have limitations that can be overcome by using a BLDC motor. The proposed system features a BLDC motor, current sensor, PID controller, and speed/direction sensor. It aims to provide two-speed bidirectional control of the auxiliary propellers through closed-loop control of the BLDC motor's speed using a PID controller. Simulation results are presented to validate that the proposed system can efficiently control the auxiliary propulsion at two speeds in both directions.
The document summarizes a study on improving the performance of a two-leg inverter fed brushless DC motor (BLDCM) drive. Key points:
1) A two-leg inverter fed BLDCM drive is proposed that uses only four switches and two current sensors, compared to a conventional three-leg inverter that uses six switches and three current sensors. This reduces switching losses and cost.
2) A MATLAB/Simulink model of the proposed two-leg inverter fed BLDCM drive with two DC input sources is developed.
3) Simulation results show the proposed drive has reduced torque ripple, lower voltage stress, lower current total harmonic distortion, and faster dynamic performance
This paper presents a control scheme for speed control system in brushless dc (BLDC) motor to be utilized for electric motorbike. While conventional motorbikes require engine and fuel, electric motorbikes require DC motor and battery pack in order to be powered up. The limitation with battery pack is that it will need to be recharged after a certain period and distance. As the recharging process is time consuming, a PID controller is designed to maintain the speed of the motor at its optimum state, thus ensuring a longer lasting battery time (until the next charge). The controller is designed to track variations of speed references and stabilizes the output speed accordingly. The simulation results conducted in MATLAB/SIMULINK® shows that the motor, equipped with the PID controller was able to track the reference speed in 7.8x10-2 milliseconds with no overshoot. The result shows optimistic possibility that the proposed controller can be used to maintain the speed of the motor at its optimum speed.
1) The document proposes a hybrid renewable energy system using a doubly fed induction generator (DFIG) driven by a wind turbine combined with photovoltaic (PV) panels.
2) A three-level neutral point clamped (NPC) inverter is used to convert the rectified voltage from the grid or DC voltage from the PV panels to a variable frequency voltage to supply the DFIG rotor.
3) Maximum power point tracking (MPPT) is used to extract maximum power from the PV panels and regulate the output voltage from the DFIG based on a vector control scheme using D-Q axis current control.
Analysis and control of four quadrant operation of three phase brushless dc (...eSAT Publishing House
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
This document discusses speed control of a DC motor using a chopper (buck converter) and PI controller. A buck converter is used to vary the armature voltage of the separately excited DC motor, allowing control of motor speed. A PI controller is employed to remove delay and provide fast control by minimizing the error between the reference speed and actual motor speed measured by a tachogenerator. The complete system including DC motor, buck converter and PI controller is modeled in MATLAB/Simulink. Simulation results for motor parameters like speed, current and torque are analyzed to verify the speed control methodology.
Speed Control of Brushless DC Motor using Different Intelligence SchemesIRJET Journal
This document discusses speed control of a brushless DC motor using different control schemes, including an I-controller, PI-controller, and fuzzy logic controller. It first provides background on BLDC motors and their advantages over brushed DC motors. It then discusses modeling of a BLDC motor and the design of an I-controller, PI-controller, and fuzzy logic controller for speed control. Simulation results show that the fuzzy logic controller provides the best performance with minimum overshoot and settling time. A comparison table confirms that the fuzzy logic controller has the best response dynamics of the three controllers tested.
This document discusses indirect vector control of induction motor drives. It begins by explaining the operating principle of indirect vector control, which uses a speed feedback loop and current feedback loop. It then describes the various components of an indirect vector controlled induction motor drive system, including the speed controller, field weakening controller, vector controller, current controller, voltage source inverter, and induction motor. The vector controller computes the d-axis and q-axis stator current components to control flux and torque. The current controller matches the actual stator currents to the reference currents to provide gate signals to the voltage source inverter. Modelling and simulation of the indirect vector controlled induction motor drive using different speed controllers is then discussed.
Fuzzy Controller for Speed Control of BLDC motor using MATLABIRJET Journal
This document presents a fuzzy logic controller for speed control of a brushless DC motor (BLDC) using MATLAB/Simulink. It begins with an introduction to BLDC motors and their modeling. It then describes the MATLAB/Simulink model developed including electrical equations, mechanical equations, inverter model, and fuzzy inference system. Simulation results are shown for the motor speed at different reference speeds and load torques. The fuzzy logic controller is found to provide better speed control performance compared to PI controllers. The document concludes that adding current control could further improve the motor's performance.
Speed Control of Brushless Dc Motor Using Fuzzy Logic Controlleriosrjce
This paper presents a control scheme of a fuzzy logic for the brushless direct current (BLDC)
permanent magnet motor drives. The mathematical model of BLDC motor and fuzzy logic algorithm is derived.
The controller is designed to tracks variations of speed references and stabilizes the output speed during load
variations. The BLDC has some advantages compare to the others type of motors, however the nonlinearity of
the BLDC motor drive characteristics, because it is difficult to handle by using conventional proportionalintegral
(PI) controller. The BLDC motor is fed from the inverter where the rotor position and current
controller is the input. In order to overcome this main problem, the fuzzy logic control is learned continuously
and gradually becomes the main effective control. The effectiveness of the proposed method is verified by
develop simulation model in MATLAB-Simulink program. The simulation results show that the proposed fuzzy
logic controller (FLC) produce significant improvement control performance compare to the PI controller for
both condition controlling speed reference variations and load disturbance variations. Fuzzy logic is introduced
in order to suppressing the chattering and enhancing the robustness of the controlled system. Fuzzy boundary
layer is developed to provide smother transition to the equivalent control. Smaller overshoot in the speed
response and much better disturbance rejecting capabilities.
DTC Scheme for a Four-Switch Inverter-Fed PMBLDC Motor Emulating the Six-Swit...IJRST Journal
The paper deals with the direct torque control (DTC) of brushless DC (BLDC) motor drives fed by four-switch three phase inverters (FSTPI) rather than six-switch inverters (SSTPI) in conventional drives. For any three phase inverter require six switches, but these switches are reduced to four. This reduction of power switches from six to four improves the reliability of the inverter, size of the inverter is reduced and cost of the inverter is also reduces. The FSTPI could be regarded as a reconfigured topology of the SSTPI in case of a switch/leg failure which represents a crucial reliability benefit for many applications especially in electric and hybrid propulsion systems. The DTC of FSTPI-fed BLDC motor drives is treated considering two strategies, such as: 1) DTC-1: a strategy inspired from the one intended to SSTPI-fed BLDC motor drives; 2) DTC-2: a strategy that considers a dedicated vector selection subtable in order to independently control the torques developed by the phases connected to the FSTPI legs during their simultaneous conduction. The operational principle of the four-switch BLDC motor drive and the developed control scheme are theoretically analyzed and the performance is demonstrated by simulation.
IRJET- Performance Enhancement of DFIG based Wind Farms Integrated in Power S...IRJET Journal
This document discusses improving the performance of doubly fed induction generator (DFIG) based wind farms integrated into power systems under voltage dips. It proposes coordinating the automatic voltage regulator (AVR) and power system stabilizer (PSS) of synchronous generators using fuzzy logic. A fuzzy coordinator is designed to eliminate harmful interactions between AVR and PSS during faults by adjusting their gains based on rotor angle and terminal voltage deviations. Simulation results on the IEEE 10-machine 39-bus system show the fuzzy coordinator helps transmit voltage at the point of common coupling and reduces DFIGs' reactive power needs under faults, enhancing system performance.
IRJET - Power Generation using Windmill using Movement of Vehicles in HighwaysIRJET Journal
This document describes a project to generate electrical power from wind energy created by vehicle movement on highways. A vertical axis wind turbine is mounted in the median of a highway to capture wind from both sides. As vehicles pass in opposite directions, they create wind shear and turbulence that the turbine converts to rotational energy. This spins a permanent magnet DC generator coupled to the turbine, producing electricity that is stored in a battery. A DC-DC converter boosts the battery voltage, and an inverter converts it to AC power to run streetlights along the highway at night, harnessing renewable wind energy from vehicle movement.
Improved Transient Compensation using PI-SRF Control Scheme Based UHVDC for O...IRJET Journal
This document presents a PI controller-based unified high voltage direct current (UHVDC) system for offshore wind power plants to improve transient compensation. The proposed UHVDC system includes both series and shunt compensators to provide symmetrical and asymmetrical fault handling, smooth power transfer, regulated DC link voltage, and improved reliability. A PI controller using synchronous reference frame (SRF) control is proposed to achieve fast transient management. Simulation results in MATLAB/Simulink show the PI-SRF control technique regulates the DC link voltage and reduces transients during faults compared to conventional control schemes. The control strategy independently controls the shunt and series compensators to maintain power flow and voltage stability under normal and fault conditions.
Brushless Dc Motor Speed Control Using Proportional-Integral And Fuzzy Contro...IOSR Journals
This document summarizes and compares proportional-integral (PI) control and fuzzy logic control for speed regulation of a permanent magnet brushless DC motor. It first provides background on brushless DC motors and reviews previous literature on speed control techniques. It then describes implementing PI control in closed loop simulations, comparing three tuning methods. Fuzzy logic control is also implemented using two inputs (speed and current errors) and simulation results are presented. Both controllers are able to regulate speed under varying load torques and reference speeds, with fuzzy logic control having better performance in terms of overshoot, settling time and speed drop compared to PI control.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document presents a new control method for improving the performance of low power wind-driven wound rotor induction generators. The proposed method combines input voltage control and slip power control to achieve better efficiency and power factor over a wide range of speeds. Simulation and experimental results show that the combined control method improves both efficiency and power factor compared to conventional slip power control alone. The combined control allows the generator to operate closer to its maximum torque point for higher efficiency at each operating speed.
The document describes the design of a hybrid electric drive system consisting of: a power supply circuit, pulse width modulation for speed control, digital logic programmed with Verilog in a GAL chip, and an H-bridge circuit for bi-directional motor control. Key aspects of the design include dynamic and counter-current braking functionality. Testing showed the motor could ramp up and down speed as specified and brake in a controlled manner within current limits. The total cost of components for the designed circuit was under $50.
Grid Connected Wind Turbine Generator with Real and Reactive Power ControlIRJET Journal
This document proposes a grid-connected wind turbine system with a permanent magnet synchronous generator (PMSG) for variable speed operation. A diode bridge rectifier converts the AC voltage from the PMSG to DC, which is fed to a boost converter for voltage regulation. The output of the boost converter feeds a three-phase inverter to inject real and reactive power into the grid using PI controllers with grid current and voltage feedback. Maximum power point tracking (MPPT) is achieved by varying the turbine pitch angle using a voltage-controlled technique to extract maximum power for varying wind speeds. Simulation results in MATLAB/Simulink demonstrate the performance of the system.
This document discusses using an artificial neural network (ANN) for speed and torque control of a three-phase induction motor. It proposes a new ANN-based method for flux position estimation, sector selection, and voltage vector selection for direct torque control of induction motors. Simulation and experimental results show the ANN-based approach reduces torque and flux ripples compared to conventional direct torque control. The ANN-based speed controller also achieves good dynamic performance of the induction motor drive. Results indicate the ANN-based direct torque control scheme has better performance than the modified direct torque control scheme.
A solar fed BLDC motor drive for mixer grinder using a buck converter IJECEIAES
In large and small scale applications, different kinds of variable speed driving systems can be found. For saving the energy consumption of these devices, eco-friendly electronics are used, which lead to the development of the Brushless DC motor (BLDC). Its higher power density, higher efficiency, higher torque at low speed, and low maintenance enhances the use of a BLDC motor. The existing mixer grinder consists of the universal motor, which operates in alternating current supply due to high starting torque characteristics and simple controlling of the speed. The absence of brushes and the reduction of noise in the BLDC extends its life and makes it ideal in a mixer grinder. A solar-powered BLDC motor drive for a mixer grinder is presented in this paper. A DC-DC buck converter is utilized to operate the PV (photovoltaic) array at its maximum power. The proposed hysteresis current control BLDC system has been developed in the MATLAB. The commercially available mixer grinder is presented along with the proposed simulated system for performance comparison. It can be concluded that at the no load condition, the efficiency of the experimental existing mixer grinder is 51.03% and simulated proposed system is 81.25% and at load condition, the efficiency of the experimental mixer grinder is 49.32% and simulated system is 79.85%.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study on power control of doubly fed induction generatorIRJET Journal
This document summarizes a study on controlling power from a doubly fed induction generator (DFIG) for wind turbine systems. A DFIG allows variable speed operation through the use of an AC-DC-AC converter connected to its rotor. The converter controls both active and reactive power independently of generator speed. The study examines control strategies for the rotor side converter to regulate speed and power, and the grid side converter to control DC bus voltage and power flow. Simulation results show the DFIG control system can maintain stable power output despite fluctuating wind speed.
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.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Controllers are used in renewable energy systems like electric vehicles, wind turbines, and solar power plants to regulate various functions. Modern controllers for electric vehicles use pulse width modulation to smoothly control motor speed and acceleration. Advanced controllers for wind turbines and solar plants employ strategies like variable pitch control, maximum power point tracking, and fuzzy logic to optimize power capture despite changing environmental conditions. Controllers are critical for integrating renewable sources into smart grids and ensuring stable, efficient system operation as use of intermittent renewables increases.
Analysis and control of four quadrant operation of three phase brushless dc (...eSAT Publishing House
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
This document discusses speed control of a DC motor using a chopper (buck converter) and PI controller. A buck converter is used to vary the armature voltage of the separately excited DC motor, allowing control of motor speed. A PI controller is employed to remove delay and provide fast control by minimizing the error between the reference speed and actual motor speed measured by a tachogenerator. The complete system including DC motor, buck converter and PI controller is modeled in MATLAB/Simulink. Simulation results for motor parameters like speed, current and torque are analyzed to verify the speed control methodology.
Speed Control of Brushless DC Motor using Different Intelligence SchemesIRJET Journal
This document discusses speed control of a brushless DC motor using different control schemes, including an I-controller, PI-controller, and fuzzy logic controller. It first provides background on BLDC motors and their advantages over brushed DC motors. It then discusses modeling of a BLDC motor and the design of an I-controller, PI-controller, and fuzzy logic controller for speed control. Simulation results show that the fuzzy logic controller provides the best performance with minimum overshoot and settling time. A comparison table confirms that the fuzzy logic controller has the best response dynamics of the three controllers tested.
This document discusses indirect vector control of induction motor drives. It begins by explaining the operating principle of indirect vector control, which uses a speed feedback loop and current feedback loop. It then describes the various components of an indirect vector controlled induction motor drive system, including the speed controller, field weakening controller, vector controller, current controller, voltage source inverter, and induction motor. The vector controller computes the d-axis and q-axis stator current components to control flux and torque. The current controller matches the actual stator currents to the reference currents to provide gate signals to the voltage source inverter. Modelling and simulation of the indirect vector controlled induction motor drive using different speed controllers is then discussed.
Fuzzy Controller for Speed Control of BLDC motor using MATLABIRJET Journal
This document presents a fuzzy logic controller for speed control of a brushless DC motor (BLDC) using MATLAB/Simulink. It begins with an introduction to BLDC motors and their modeling. It then describes the MATLAB/Simulink model developed including electrical equations, mechanical equations, inverter model, and fuzzy inference system. Simulation results are shown for the motor speed at different reference speeds and load torques. The fuzzy logic controller is found to provide better speed control performance compared to PI controllers. The document concludes that adding current control could further improve the motor's performance.
Speed Control of Brushless Dc Motor Using Fuzzy Logic Controlleriosrjce
This paper presents a control scheme of a fuzzy logic for the brushless direct current (BLDC)
permanent magnet motor drives. The mathematical model of BLDC motor and fuzzy logic algorithm is derived.
The controller is designed to tracks variations of speed references and stabilizes the output speed during load
variations. The BLDC has some advantages compare to the others type of motors, however the nonlinearity of
the BLDC motor drive characteristics, because it is difficult to handle by using conventional proportionalintegral
(PI) controller. The BLDC motor is fed from the inverter where the rotor position and current
controller is the input. In order to overcome this main problem, the fuzzy logic control is learned continuously
and gradually becomes the main effective control. The effectiveness of the proposed method is verified by
develop simulation model in MATLAB-Simulink program. The simulation results show that the proposed fuzzy
logic controller (FLC) produce significant improvement control performance compare to the PI controller for
both condition controlling speed reference variations and load disturbance variations. Fuzzy logic is introduced
in order to suppressing the chattering and enhancing the robustness of the controlled system. Fuzzy boundary
layer is developed to provide smother transition to the equivalent control. Smaller overshoot in the speed
response and much better disturbance rejecting capabilities.
DTC Scheme for a Four-Switch Inverter-Fed PMBLDC Motor Emulating the Six-Swit...IJRST Journal
The paper deals with the direct torque control (DTC) of brushless DC (BLDC) motor drives fed by four-switch three phase inverters (FSTPI) rather than six-switch inverters (SSTPI) in conventional drives. For any three phase inverter require six switches, but these switches are reduced to four. This reduction of power switches from six to four improves the reliability of the inverter, size of the inverter is reduced and cost of the inverter is also reduces. The FSTPI could be regarded as a reconfigured topology of the SSTPI in case of a switch/leg failure which represents a crucial reliability benefit for many applications especially in electric and hybrid propulsion systems. The DTC of FSTPI-fed BLDC motor drives is treated considering two strategies, such as: 1) DTC-1: a strategy inspired from the one intended to SSTPI-fed BLDC motor drives; 2) DTC-2: a strategy that considers a dedicated vector selection subtable in order to independently control the torques developed by the phases connected to the FSTPI legs during their simultaneous conduction. The operational principle of the four-switch BLDC motor drive and the developed control scheme are theoretically analyzed and the performance is demonstrated by simulation.
IRJET- Performance Enhancement of DFIG based Wind Farms Integrated in Power S...IRJET Journal
This document discusses improving the performance of doubly fed induction generator (DFIG) based wind farms integrated into power systems under voltage dips. It proposes coordinating the automatic voltage regulator (AVR) and power system stabilizer (PSS) of synchronous generators using fuzzy logic. A fuzzy coordinator is designed to eliminate harmful interactions between AVR and PSS during faults by adjusting their gains based on rotor angle and terminal voltage deviations. Simulation results on the IEEE 10-machine 39-bus system show the fuzzy coordinator helps transmit voltage at the point of common coupling and reduces DFIGs' reactive power needs under faults, enhancing system performance.
IRJET - Power Generation using Windmill using Movement of Vehicles in HighwaysIRJET Journal
This document describes a project to generate electrical power from wind energy created by vehicle movement on highways. A vertical axis wind turbine is mounted in the median of a highway to capture wind from both sides. As vehicles pass in opposite directions, they create wind shear and turbulence that the turbine converts to rotational energy. This spins a permanent magnet DC generator coupled to the turbine, producing electricity that is stored in a battery. A DC-DC converter boosts the battery voltage, and an inverter converts it to AC power to run streetlights along the highway at night, harnessing renewable wind energy from vehicle movement.
Improved Transient Compensation using PI-SRF Control Scheme Based UHVDC for O...IRJET Journal
This document presents a PI controller-based unified high voltage direct current (UHVDC) system for offshore wind power plants to improve transient compensation. The proposed UHVDC system includes both series and shunt compensators to provide symmetrical and asymmetrical fault handling, smooth power transfer, regulated DC link voltage, and improved reliability. A PI controller using synchronous reference frame (SRF) control is proposed to achieve fast transient management. Simulation results in MATLAB/Simulink show the PI-SRF control technique regulates the DC link voltage and reduces transients during faults compared to conventional control schemes. The control strategy independently controls the shunt and series compensators to maintain power flow and voltage stability under normal and fault conditions.
Brushless Dc Motor Speed Control Using Proportional-Integral And Fuzzy Contro...IOSR Journals
This document summarizes and compares proportional-integral (PI) control and fuzzy logic control for speed regulation of a permanent magnet brushless DC motor. It first provides background on brushless DC motors and reviews previous literature on speed control techniques. It then describes implementing PI control in closed loop simulations, comparing three tuning methods. Fuzzy logic control is also implemented using two inputs (speed and current errors) and simulation results are presented. Both controllers are able to regulate speed under varying load torques and reference speeds, with fuzzy logic control having better performance in terms of overshoot, settling time and speed drop compared to PI control.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document presents a new control method for improving the performance of low power wind-driven wound rotor induction generators. The proposed method combines input voltage control and slip power control to achieve better efficiency and power factor over a wide range of speeds. Simulation and experimental results show that the combined control method improves both efficiency and power factor compared to conventional slip power control alone. The combined control allows the generator to operate closer to its maximum torque point for higher efficiency at each operating speed.
The document describes the design of a hybrid electric drive system consisting of: a power supply circuit, pulse width modulation for speed control, digital logic programmed with Verilog in a GAL chip, and an H-bridge circuit for bi-directional motor control. Key aspects of the design include dynamic and counter-current braking functionality. Testing showed the motor could ramp up and down speed as specified and brake in a controlled manner within current limits. The total cost of components for the designed circuit was under $50.
Grid Connected Wind Turbine Generator with Real and Reactive Power ControlIRJET Journal
This document proposes a grid-connected wind turbine system with a permanent magnet synchronous generator (PMSG) for variable speed operation. A diode bridge rectifier converts the AC voltage from the PMSG to DC, which is fed to a boost converter for voltage regulation. The output of the boost converter feeds a three-phase inverter to inject real and reactive power into the grid using PI controllers with grid current and voltage feedback. Maximum power point tracking (MPPT) is achieved by varying the turbine pitch angle using a voltage-controlled technique to extract maximum power for varying wind speeds. Simulation results in MATLAB/Simulink demonstrate the performance of the system.
This document discusses using an artificial neural network (ANN) for speed and torque control of a three-phase induction motor. It proposes a new ANN-based method for flux position estimation, sector selection, and voltage vector selection for direct torque control of induction motors. Simulation and experimental results show the ANN-based approach reduces torque and flux ripples compared to conventional direct torque control. The ANN-based speed controller also achieves good dynamic performance of the induction motor drive. Results indicate the ANN-based direct torque control scheme has better performance than the modified direct torque control scheme.
A solar fed BLDC motor drive for mixer grinder using a buck converter IJECEIAES
In large and small scale applications, different kinds of variable speed driving systems can be found. For saving the energy consumption of these devices, eco-friendly electronics are used, which lead to the development of the Brushless DC motor (BLDC). Its higher power density, higher efficiency, higher torque at low speed, and low maintenance enhances the use of a BLDC motor. The existing mixer grinder consists of the universal motor, which operates in alternating current supply due to high starting torque characteristics and simple controlling of the speed. The absence of brushes and the reduction of noise in the BLDC extends its life and makes it ideal in a mixer grinder. A solar-powered BLDC motor drive for a mixer grinder is presented in this paper. A DC-DC buck converter is utilized to operate the PV (photovoltaic) array at its maximum power. The proposed hysteresis current control BLDC system has been developed in the MATLAB. The commercially available mixer grinder is presented along with the proposed simulated system for performance comparison. It can be concluded that at the no load condition, the efficiency of the experimental existing mixer grinder is 51.03% and simulated proposed system is 81.25% and at load condition, the efficiency of the experimental mixer grinder is 49.32% and simulated system is 79.85%.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study on power control of doubly fed induction generatorIRJET Journal
This document summarizes a study on controlling power from a doubly fed induction generator (DFIG) for wind turbine systems. A DFIG allows variable speed operation through the use of an AC-DC-AC converter connected to its rotor. The converter controls both active and reactive power independently of generator speed. The study examines control strategies for the rotor side converter to regulate speed and power, and the grid side converter to control DC bus voltage and power flow. Simulation results show the DFIG control system can maintain stable power output despite fluctuating wind speed.
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.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Controllers are used in renewable energy systems like electric vehicles, wind turbines, and solar power plants to regulate various functions. Modern controllers for electric vehicles use pulse width modulation to smoothly control motor speed and acceleration. Advanced controllers for wind turbines and solar plants employ strategies like variable pitch control, maximum power point tracking, and fuzzy logic to optimize power capture despite changing environmental conditions. Controllers are critical for integrating renewable sources into smart grids and ensuring stable, efficient system operation as use of intermittent renewables increases.
IRJET- Power Quality Improvement in SEIGIRJET Journal
This document summarizes research on improving power quality in self-excited induction generators (SEIGs). SEIGs are becoming more popular for renewable energy sources due to advantages over synchronous generators, but have drawbacks of reactive power consumption and variable voltage regulation. The document discusses how static power capacitors can control SEIG output voltage and synchronous condensers can control reactive power consumption. It then reviews literature on SEIG control methods and proposes a system using switched capacitors to regulate voltage and a resistive dump load controlled by a microcontroller to regulate voltage and frequency under varying conditions from the prime mover. The system aims to provide low-cost power for isolated areas using SEIGs.
This document discusses electrical drives using AC and DC motors. It defines electrical drives as using around 50% of electrical energy for electric motors in industries and applications. The key components of electrical drives are the motor, power source, and control methods. For AC motor drives, the document discusses induction motors and synchronous motors. It also summarizes methods for controlling speed and torque of induction motors including stator voltage control, rotor voltage control, and frequency control. The document concludes that variable speed drives can improve energy efficiency compared to constant speed drives.
This document discusses drives used for heating, ventilation and air conditioning systems. It compares AC and DC drives, describing their advantages and disadvantages. AC drives have lower motor costs but higher power converter costs compared to DC drives. Microprocessor control is discussed for both AC and DC drives. Common industrial applications of microprocessor controlled AC drives are also listed, such as for fans, pumps and compressors. The document concludes with advantages of microprocessor controlled drives like better process control and reliability.
Regeneration in Variable Frequency Drives and Energy Saving MethodsIRJET Journal
This document discusses methods for regenerating energy from variable frequency drives to save costs. When an induction motor decelerates, it generates electricity that is normally wasted as heat through braking resistors. Regenerative converters can return this energy to the grid instead. Three types are described: regenerative converters use PWM to feed energy back through the supply line; sinusoidal PWM converters regulate voltage while improving power quality; and matrix converters directly convert AC to AC with minimal components. Matrix converters integrate regeneration and driving but have limited voltage transfer. Regenerative converters provide significant utility cost savings, especially for applications with frequent braking like cranes or elevators.
IRJET - Design of Power Converters for Renewable Energy Sources and Electric ...IRJET Journal
This document discusses the design of three power converters for renewable energy applications:
1. A reversible voltage inverter for an energy storage system, with a liquid cooling system and 70 kW output.
2. A power inverter for solar power plants, converting AC to DC for battery charging and vice versa, with 60 kW output.
3. A fast charger for electric vehicles with a 70 kW three-arm DC buck converter and liquid cooling system.
Numerical simulations were used to analyze power losses in the fast charger converter. The converters use IGBT modules and liquid cooling systems, and are controlled by digital signal processors.
Speed Control of BLDC Motor with Four Quadrant Operation Using dsPICijsrd.com
Brushless DC (BLDC) motor drives are becoming more popular in industrial and traction applications. Hence the control of BLDC motor in four quadrants is very vital. The flexibility of the drive system is increased using digital controller. In this paper the PWM signals for driving the power inverter bridge for BLDC motor have been successfully implemented using a dsPIC controller and the motor can be controlled in all the four quadrants without any loss of power .Energy is conserved during regenerative braking period. The digital controller dsPIC, is advantageous over other controller, as it combines the calculation capability of digital signal processor and controlling capability of PIC microcontroller to achieve a precise control. Simulation of the proposed model is done by using MATLAB/Simulink.
Interfacing and Commissioning of Motor and Drive to the Tandem test jigIJERA Editor
The motors and drives have wide applications from servos to traction and it is mainly used in automation industry, CNC machines and robots. The application of interfacing and commissioning of motor and drive to the tandem test jig helps to achieve improved reliability and cost effectiveness. This paper mainly describes how motors and drive system is interfaced to tandem test jig.BG605 motor grader vehicle is used for grading operation and bank cutting operation of roads. Tandem is a part of BG605 Motor grader equipment and it is used for transmission of power in the equipment. Testing of the tandem before assembling on to the vehicle is very much essential.
A Novel Control Method Of Variable Speed Pumped Storage Power PlantIOSR Journals
This document summarizes a novel control method for variable speed pumped storage power plants using direct torque control (DTC) and a two-level voltage source converter (2LVSC). It begins by introducing variable speed pumped storage and some common control methods like static frequency converters and cycloconverters. It then provides more detail on DTC strategy for controlling a doubly fed asynchronous machine, including modeling the machine equations and analyzing the effect of voltage vectors on torque and flux regulation. Simulation results are presented showing improved efficiency compared to conventional plants from applying the novel DTC with 2LVSC control method.
This document summarizes a research paper that proposes an adaptive PID speed controller for a brushless DC motor. The paper begins with an introduction to brushless DC motors and common speed control methods like PI, PID, fuzzy logic and PWM controllers. It then discusses developing an adaptive PID controller that combines a PID controller with an auto-tuning method. This allows the controller to adapt to changing system parameters. The paper describes modeling the BLDC motor and speed control systems in MATLAB/Simulink. Simulation results are presented and analyzed to verify the adaptive PID controller's performance. The adaptive PID controller is found to improve system adaptability compared to other control methods.
Electric Vehicle Driven by Solar PV Batteries and Regenerative Brakes via a Z...ijtsrd
This paper proposes a unique regenerative braking method based on a Brushless DC BLDC motor. Braking may be accomplished using the suggested technique by applying a varied Stator voltage from a multi cell battery system DC DC buck converter. A simulation was utilised to test the performance of the suggested braking mechanism. The suggested regenerative braking technology is viable and efficient, according to simulation findings. Furthermore, this study presents the most basic technology for regenerative braking utilising a BLDC motor to increase the mileage of lightweight electric cars EVs . Akansha Sneha | Neeti Dugaya | Dr. Geetam Richhariya | Dr. Manju Gupta "Electric Vehicle Driven by Solar PV Batteries and Regenerative Brakes via a Zeta Converter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-7 , December 2022, URL: https://www.ijtsrd.com/papers/ijtsrd52591.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/52591/electric-vehicle-driven-by-solar-pv-batteries-and-regenerative-brakes-via-a-zeta-converter/akansha-sneha
Speed Control of a Seperately Excited DC Motor by Implementing Fuzzy Logic Co...IRJET Journal
This document describes the use of a fuzzy logic controller to control the speed of a separately excited DC motor. A mathematical model of the DC motor is presented. A PID controller is also designed for speed control and its performance is compared to the fuzzy logic controller. A fuzzy logic controller with two inputs - speed error and change in speed error - and seven fuzzy rules is developed. Simulation results in MATLAB/Simulink show that the fuzzy logic controller has better performance than the PID controller in terms of overshoot, settling time, and steady state error for speed control of the separately excited DC motor.
The document describes a project that aims to improve the efficiency of electric vehicles through regenerative braking using ultracapacitors. The key objectives are to develop a low-cost system to rapidly recover braking energy and reduce stress on the main batteries. The proposed system uses an ultracapacitor bank and buck-boost converter to capture energy during braking and provide power during acceleration, minimizing energy losses. The system was simulated in Proteus and a hardware circuit was implemented with a PIC microcontroller to independently control the MOSFETs during motoring, braking and accelerating phases based on accelerator and brake potentiometer values. Testing showed efficient regenerative braking and extended battery life.
This document provides an introduction and overview of AC drive fault diagnosis and detection. It discusses the basics of AC drives, including PWM inverters and semiconductor technologies. It describes common faults in AC drives systems, including faults in the AC power line, frequency converter, and AC motor. It also discusses conventional protection schemes for AC drives and various fault diagnosis and detection methods, such as expert knowledge-based systems and online condition monitoring of the AC motor. The document is organized into sections on introduction, AC drive basics, faults, protection, and diagnosis/detection methods.
This document proposes a direct torque control strategy for doubly fed induction machine-based wind turbines that can operate under voltage dips without crowbar protection. The control strategy generates a rotor flux amplitude reference to control the torque of the wind turbine and reduce stator and rotor overcurrents during faults. It also provides fast dynamic response. While the control does not eliminate the need for crowbar protection entirely, it can prevent the crowbar from activating during low-depth voltage dips. The direct torque control approach maintains machine connection to the grid and reduces torque oscillations during faults.
This course covers electric drive systems controlled by power electronic converters. It discusses DC drives, induction motor drives controlled from the stator side and rotor side, and synchronous motor drives. Students will learn about drive characteristics and modeling, DC drive configurations, closed-loop control of induction motors, efficient speed control methods for induction motors, and control techniques for synchronous motors. The course aims to provide an understanding of electric drive performance and applications in various industries.
IRJET- Phase Conversion of VFD based Induction MotorIRJET Journal
This document discusses using a variable frequency drive (VFD) to control the speed of a three-phase induction motor. A VFD allows the motor to operate at variable speeds, which can provide energy savings compared to operating at a single rated speed. The VFD converts incoming single-phase power to three-phase power using a rectifier to produce DC power, then an inverter uses pulse width modulation to generate a three-phase AC output that can be varied in frequency to control motor speed. This setup allows flexible control of the induction motor's speed while improving efficiency over constant speed operation.
This document describes using a fuzzy logic controller and PID controller to control the speed of a DC motor. It first provides background on DC motors and controllers. It then discusses the design of a fuzzy logic controller for a DC motor, including defining the inputs, rule base, inference engine, and defuzzification method. The document presents the modeling of a separately excited DC motor. It then simulates the motor's speed response using a PID controller and fuzzy logic controller in MATLAB. The results show that the fuzzy logic controller has better transient and steady-state response than the PID controller for controlling the non-linear DC motor speed.
This document describes using a fuzzy logic controller and PID controller to control the speed of a DC motor. It first provides background on DC motors and controllers. It then discusses the design of a fuzzy logic controller for a DC motor, including defining the inputs, rule base, inference engine, and defuzzification method. The document presents the modeling of a separately excited DC motor. It then simulates the motor's speed response using a PID controller and fuzzy logic controller in MATLAB. The results show that the fuzzy logic controller has better transient and steady-state response than the PID controller for controlling the non-linear DC motor speed.
Similar to 3.10 eet in_electrical_systems[1] - copy (20)
1. Question bank for Energy Managers & Energy Auditors
Chapter 3.10: Energy Efficient Technologies in Electrical Systems
Part-I: Objective type questions and answers
1. Maximum demand controller is used to ___________.
a) switch off essential loads in a logical sequence b) exceed the demand of the plant
c) switch off non-essential loads in a logical sequence d) controls the power factor of the plant
2. Capacitors with automatic power factor controller when installed in a plant:
a) reduces active power drawn from grid b) reduces the reactive power drawn from grid
c) reduces the voltage of the plant d) increases the load current of the plant
3. _________ controls the power factor of the installation by giving signals to switch on or off power
factor correction capacitors.
a) KILOVAR b) Automatic power factor control relay
c) Intelligent power factor controller d) Maximum demand controller
4. __________ determines the rating of capacitance connected in each step during the first hour of its
operation and stores them in memory.
a) Maximum demand controller b) Intelligent power factor controller
c) Automatic power factor controller d) KILOVAR
5. The following function can not be achieved with automatic power factor controllers.
a) Voltage control b) KILOVAR control c) kW control d) PF control
6. The following features apply to energy efficient motors by design:
a) Energy efficient motors last longer
b) Starting torque for efficient motors may be lower than for standard motors
State whether the two statements are True or False?
7. Eddy current drive can be a retrofit for ________.
a) constant speed system requirement b) variable speed system requirement
c) dual speed system requirement only d) none of the above
8. Electronic variable frequency drive (VFD) connected to motors:
a) provide variable speed with high efficiency
b) induces eddy-current in the secondary member of the clutch mechanism
c) is not suitable for variable torque load
d) does not provide variable speed and has low-efficiency
9. Variable speed can not be obtained with ____.
a) DC motors controller b) AC motor controller
c) soft starter controller d) AC & DC controllers
3.10 EET in electrical systems - revised (table format) 73
2. Question bank for Energy Managers & Energy Auditors
10. Energy savings potential of variable torque applications compared to constant torque application is:
a) higher b) lower c) equal d) none of the above
11. As an energy efficient application, slip power recovery system fits well for ____.
a) Squirrel cage and slip ring motors b) DC motor
c) Slip ring motors only d) None of the above
12. Energy efficient transformer core is made up of ______.
a) silicon alloyed iron (grain oriented) b) copper
c) amorphous core - metallic glass alloy d) none of the above
13. The basic functions of electronic ballast excludes one of the following:
a) to ignite the lamp b) to stabilize the gas discharge
c) to reduce lumen output of the lamp d) to supply power to the lamp
14. Select the application of fluid coupling fitting from the following:
a) acts as a voltage limiter b) enables no-load start-up of prime-mover
c) works on the principle of eddy current d) none of the above
15. The characteristic of conventional ballast in lighting application is one among the following:
a) They have low operational losses than electronic ballasts.
b) They have tuned circuit to deliver power at 25 Hz
c) They do not require a mechanical switch (starter)
d) They have high operational losses and high temperature rise
16. Application of occupancy sensors is well suited for ___.
a) day light based controllers b) night based controllers
c) motor controllers d) movement or noise detector in room space
17. Find the odd retrofit group from the following:
a) Occupancy sensors b) timer based control
c) photo sensors d) capacitor based control
18. Application of timers as a retrofit will assist in saving energy in areas of ____.
a) Lighting & motors b) Transformers c) HV- Feeder Panels d) All the above
19. Electronic soft starters are used for motors to:
a) achieve variable speed b) provide smooth start and stop
c) improve the loading c) none of the above
20. Energy efficient lighting can be planned by using the following retrofits. – State True or False
a) photo-sensor b) timer c) occupancy sensor d) localized switching
3.10 EET in electrical systems - revised (table format) 74
3. Question bank for Energy Managers & Energy Auditors
Part-II: Short type questions and answers
1. How maximum demand control can be practiced in a plant?
MD control is very important because the utility charges user not only for the energy consumed but
also for the maximum demand made irrespective energy consumed (as per two part tariff). Hence in
order to reduce the energy cost it is essential to control the maximum demand.
MD can be controlled by
Use of maximum demand controller,
Staggering load during peak load period by sequencing of loads, operating in shifts etc.
Maintaining very good pf at peak loads
2. Briefly explain the benefits of employing a demand controller
• Avoids excess maximum demand on the supply grid
• Helps in improving the load factor by truncating the peaks and flattening the load curve.
• Assists in meeting expansion plans
• Leveling plant loads to avoid peak load on feeder and electrical equipment
3. What is APFC? What are its advantages?
APFC is an acronym for “automatic power factor controller”. It is used to improve the system power
factor by automatic sensing of PF correction and control.
The advantages of APFC are
Unmanned operation of pf control,
Always maintains very good and accurate pf (as set),
Results in decreased system current and hence reduced voltage drop and power loss
automatically,
Reduced energy bill and avoids penalties both pf penalty and maximum demand.
4. Name watt loss areas for improvement by using energy efficient motors?
• Iron loss
• Stator I2R loss
• Rotor I2R loss
• Friction & windage
• Stray load loss
5. What are the technical aspects of energy efficient motors?
Energy-efficient motors last longer, and may require less maintenance. At lower temperatures,
bearing grease lasts longer; required time between re-greasing increases. Lower temperatures
translate to long lasting insulation. Generally, motor life doubles for each 10°C reduction in operating
temperature.
Speed control is crucial in some applications. In polyphase induction motors, slip is a measure of
motor winding losses. The lower the slip, the higher the efficiency. Less slippage in energy efficient
motors results in speeds about 1% faster than in standard counterparts.
Starting torque for efficient motors may be lower than for standard motors. Facility managers should
be careful when applying efficient motors to high torque applications.
3.10 EET in electrical systems - revised (table format) 75
4. Question bank for Energy Managers & Energy Auditors
6. Write brief notes on soft-starters
Soft starter provides a reliable and economical solution to these problems by delivering a controlled
release of power to the motor, thereby providing smooth, stepless acceleration and deceleration.
Motor life will be extended as damage to windings and bearings is reduced.
Soft Start & Soft Stop is built into 3 phase units, providing controlled starting and stopping with a
selection of ramp times and current limit settings to suit all applications.
7. Briefly explain the advantages of electronic soft-starters?
• Less mechanical stress
• Improved Power Factor
• Lower maximum demand
• Less mechanical maintenance
8. Explain the affinity laws concerning variable torque loads.
The following laws illustrate these relationships.
• Flow is proportional to speed
• Head is proportional to (speed)2
• Torque is proportional to (speed)2
• Power is proportional to (speed)3
9. Briefly describe the principle of variable frequency drive
The VFD operates on a simple principle. The rotational speed of an AC induction motor depends on
the number of poles in that stator and the frequency of the applied AC power. Although the number
pole in an induction motor cannot be altered easily, variable speed can be achieved through a
variation in frequency. The VFD rectifies standard 50 cycle AC line power to DC, then synthesis the
DC to a variable frequency AC output.
10. List the applications of variable frequency drive control for motors operating on pumps and fans.
• For avoiding throttling with pumps & fans
• To meet variable head requirement during cycle of operation
• To meet intermittent variations in requirement of flow/head
11. What are the means of varying speeds of induction motor?
Speed can be varied by
a) varying resistance of rotor circuit
b) using multispeed windings
c) using scherbius or Kramer drives
d) using mechanical means such as gears & pulleys
e) eddy current or fluid coupling
f) variable frequency drive
12. Explain the principle of Eddy current drive mechanism for motors.
Eddy current drive mechanism employs an eddy current clutch to vary the output speed. The clutch
consists of two parts, primary member and secondary member. The primary member is coupled to
the motor shaft while the secondary member is a free revolving part coupled to the load shaft. The
secondary member is separately excited using a DC field winding (rotating coil). The motor starts
3.10 EET in electrical systems - revised (table format) 76
5. Question bank for Energy Managers & Energy Auditors
with load at rest and a DC excitation is provided to the secondary member. This induces eddy current
in the primary member. The interaction of the fluxes produces by the two currents gives rise to a
torque at the load shaft. By varying the DC excitation the output speed can be varied to match the
load requirements. The major disadvantage of this system is relatively power efficiency particularly at
low speeds.
13. Explain slip power recovery system as a speed control mechanism of motors?
Slip power recovery system is a more efficient alternative speed control mechanism for use with slip
ring motors. In essence, a slip power recovery system varies the rotor voltage to control speed, but
instead of dissipating power through resistors, this excess power is collected from the slip rings and
returned as mechanical power to the shaft or as electrical power back to the supply line. Because of
the relatively sophisticated equipment needed, slip power recovery tends to the economical only in
relatively high power applications and where the motor speed range is 1:5 or less.
14. Name any 4 retrofit actions at a facility having more than 100 standard efficiency motors in
operation?
• Replace with high Efficiency motors based on good running hours
• Install variable speed drive controls for variable load cycle applications
• Install two speed drives having specific application
• Install flat belts drives at specific areas having V belt drives
15. Indicate where this retrofit can play a role in an industrial facility
A. Install High Efficiency motors
B. Install Adjustable Speed Drives Motors
A. As replacement to standard efficiency motors
B. For damper controlled Fans and pumps
16. Write a brief note on energy efficient transformers?
The energy efficient transformers use amorphous material-a metallic glass alloy material for the core.
The expected reduction in energy loss over conventional transformers is roughly around 70%, which
is quite significant. By using an amorphous core with unique physical and magnetic properties –
these new types of transformers have increased efficiencies even at low loads – 98.5% efficiency at
35% load.
17. Briefly explain the functions of electronic ballast.
The high frequency electronic ballast overcomes the above drawbacks. The basic functions of
electronic ballast are:
1. To ignite the lamp
2. To stabilize the gas discharge
3. To supply the power to the lamp
The electronic ballasts make use of modern power semi-conductor devices for their operation. The
circuit components form a tuned circuit to deliver power to the lamp at a high resonant frequency (in
the vicinity of 25 kHz) and voltage is regulated through an in-built feedback mechanism.
18. At least name two applications each for “Photo-sensors” and “Timer-controls”?
Applications of “photo-sensors””
• Controlling motor operation in carding machine in a textile industry
3.10 EET in electrical systems - revised (table format) 77
6. Question bank for Energy Managers & Energy Auditors
• Unmanned area light/lux level control
• Operation of water taps, etc.
Applications of “timer-controls”
• Street light control,
• motor control during starting (star-delta) and for sequencing the line operation such as
conveyors etc.
19. List various energy efficient lighting controls.
The following are various energy efficient lighting controls.
a) use of occupancy sensors
b) time based control
c) photoelectric sensor control
d) localized switching
Using the above combinations, savings in lighting energy can be realized.
20. Few actions on retrofitting a lighting installation are given below; briefly indicate areas where this
retrofit can play a role in facility.
A. Install High Efficiency Lighting with Electronic Ballasts
B. Install Occupancy Sensors
C. Install Light Sensors (Photocells)
D. Install Skylights and Delamp
E. Delamp in Overlit Areas
A. In Large production shops/hangars
B. At Conference halls
C. For street-lighting/building lighting and areas having day-lighting
D. Entrances of offices/buildings, passages
E. Warehouses, passages, corridors and less occupied areas
Part-III: Long type questions and answers
1. Explain the functions and benefits of a demand controller
High-tension (HT) consumers have to pay a maximum demand charge in addition to the usual charge
for the number of units consumed. This charge is usually based on the highest amount of power used
during some period (say 30 minutes) during the metering month. The maximum demand charge
often represents a large proportion of the total bill and may be based on only one isolated 30 minute
episode of high power use.
Maximum Demand Controller is a device designed to meet the need of industries conscious of the
value of load management. Alarm is sounded when demand approaches a preset value. If corrective
action is not taken, the controller switches off non-essential loads in a logical sequence. This
sequence is predetermined by the user and is programmed jointly by the user and the supplier of the
device. The plant equipments selected for the load management are stopped and restarted as per the
desired load profile. Demand control scheme is implemented by using suitable control contactors.
Audio and visual annunciations could also be used.
Benefits of Maximum demand controller:
3.10 EET in electrical systems - revised (table format) 78
7. Question bank for Energy Managers & Energy Auditors
Maximum demand helps in two ways:
• Avoids excess maximum demand on the supply grid, and
• Helps in improving the load factor by truncating the peaks and flattening the load curve.
Electricity billing by any utility power supply to any facility is based on ‘two-part tariff. One
component of the tariff is based on the kWh of energy consumed and the other is based on the actual
kVA (or some times kW) demand made/contracted. If the facility makes a demand more than the
contracted value, then the excess demand is billed at higher rate (2 to 3 times) than the normal rate.
Maximum demand controller helps in avoiding peaking of load by tripping and staggering such non-
priority loads to ‘off-peak’ period as each industrial application has its own load profiles / load curves.
It finds more usefulness in TOD (i.e. time of the day) control.
2. Explain at least two automatic power factor control methods?
Various types of automatic controls are available with relay / microprocessor logic. Two of the most
common controls are: Voltage Control and KVAR Control
Voltage Control:
Voltage alone can be used as a source of intelligence when the switched capacitors are applied at
point where the circuit voltage decreases as circuit load increases. Generally, where they are applied
the voltage should decrease as circuit load increases and the drop in voltage should be around 4 – 5 %
with increasing load.
Voltage is the most common type of intelligence used in substation applications, when maintaining a
particular voltage is of prime importance. This type of control is independent of load cycle. During
light load time and low source voltage, this may give leading PF at the substation, which is to be taken
note of.
KILOVAR Control:
Kilovar sensitive controls are used at locations where the voltage level is closely regulated and not
available as a control variable. The capacitors can be switched to respond to a decreasing power factor
as a result of change in system loading. This type of control can also be used to avoid penalty on low
power factor by adding capacitors in steps as the system power factor begins to lag behind the desired
value. Kilovar control requires two inputs - current and voltage from the incoming feeder, which are
fed to the PF correction mechanism, either the microprocessor or the relay.
3. List any 5 different types of energy efficient retrofits? Explain their application and benefits in 2-3
lines each.
There are several energy efficient retrofits which are listed below:
a. Energy efficient motors (EEM): Higher efficiency and flat efficiency characteristic between 50 to
100% load results in very good saving opportunities compared to standard motors.
b. Variable speed drives (VSD): VSDs by virtue of electronic control can control the speed very
accurately in closed looped system and thereby adjust the speed according to the process
requirements.
c. Electronic chokes: Electronic chokes consume 15% to 25% of power consumption of
conventional chokes.
d. Use of energy efficient lamps: Use of energy efficient lamps with higher luminous efficiency such
as CFL, sodium vapour lamps, and metal halide lamps yields energy savings without affecting
the light output.
e. Maximum demand controllers: This is useful device which senses the occurrence of peak loads
and their duration and accordingly automatically switches-off the non-priority loads, thereby
reducing peak Maximum demand and MD cost.
3.10 EET in electrical systems - revised (table format) 79
8. Question bank for Energy Managers & Energy Auditors
4. Why variable torque loads offer greatest energy savings? Explain electronic methods of speed
controllers?
In variable torque applications, Affinity law holds good which defines the relationships between
speed, flow, torque, and horsepower illustrated below:
1. Flow is proportional to speed
2. Head is proportional to square of the speed
3. Torque is proportional to square of the speed
4. Power is proportional to cube of the speed
Variable torque loads include centrifugal pumps and fans which make up the majority of large plant
loads.
Thus, theoretically, for 50% of full load requirement the power input needed would be less than 13%
of full load power. In a centrifugal pump when the flow discharge is reduced to 70% of the rated
discharge a savings of 65 percent in power is theoretically possible.
To achieve this savings, Solid state electronic VSDs are used to control the voltage and frequency
delivered to the motor to change its speed. However, in practice the savings will depend upon the
type and efficiency of variable speed drive employed and other system losses.
5. Write short notes on Energy Efficient Lighting Controls.
Compact Fluorescent Lamp
The new low energy and therefore highly cost effective compact fluorescent lamp is a recent addition
to modern lighting technology and is an attractive alternative to incandescent lamps.
Development of very stable fluorescent powders that can handle strong ultra violet radiation has
made it possible to reduce the internal diameter of tubular fluorescent lamps as much as 10 mm.
These small bore tubes form the basis for various type of compact fluorescent. The compact
fluorescent lamp basically is a low wattage, low-pressure gas discharge lamp.
Because of the small diameter of the lamp tube and consequent high wall loading, the surface
temperature of this lamp is higher than that of a conventional fluorescent lamp. This results in
increase in the vapour pressure inside the tube and consequently lower light output at normal
ambient temperature within the luminaire. To counteract this either amalgam technique or principle
of cool spot is employed. These measures reduce the vapour pressure and maintain the light output.
Energy Savings
It is self evident that price of such a complicated compact fluorescent lamp exceeds the price of a
simple incandescent lamp many times. However, by virtue of much lower energy consumption of
these lamps the higher initial cost is more than paid back. The energy cost comparison between
incandescent and compact fluorescent lamp is shown in Table
Energy Cost Comparison
Lamp Wattage, W Efficacy, LM/W Average Life, (Hrs) Energy saving, %
Incandescent 60 12 1000 -
Compact Fluorescent 9 67 7500 80
The use of compact fluorescent lamp not only saves considerable amount of energy but also brings
with it an overall reduction in operating cost. The above Table shows a comparison of these costs for a
60 W incandescent and a compact fluorescent lamp. The comparison is based on a burning time of
5000 hours and electricity tariff of Rs.1.50 per unit and normal lamp prices. As can be seen the
energy savings is 65 to 80% at an operating cost of 50%.
3.10 EET in electrical systems - revised (table format) 80