Ha Thanh Vo, Nam Thanh Hoang, Phuong Hoang Vu, Minh Trong Tran, Dich Quang Nguyen, “FCS-Model Predictive Control of Induction Motors feed by MultilLevel Casaded H-Bridge Inverter”, RCEEE-2018.
TORQUE RIPPLE MINIMIZATION OF MATRIX CONVERTER-FED PMSM DRIVES USING ADVANCED...ijscmcj
An advanced direct torque control (DTC) technique using Model predictive control (MPC) is proposed for matrix converter (MC)-based permanent-magnet synchronous motor (PMSM) drive system, which reduces the torque ripples, does not need the duty cycle calculation, and ensures the fixed switching frequency. Analytical expressions of change rates of torque and flux of PMSM as a function of MC - dqo components are derived. The predictive model of PMSM and MC is realized by means of State model. Then, the advanced MC-fed DTC algorithm is implemented based on Cost function evaluation. The simulation results exhibit remarkable torque ripple reduction with the help of MPC. As a result, the proposed strategy is proved to be effective in minimizing the torque ripples for MC-based PMSM drives.
Investigation of THD for Cascaded Multi-Level Inverter Using Multicarrier Mod...IJERA Editor
A novelty kind of Multilevel converters are used in high voltage and high power application of industry field, can able to produce near sinusoidal voltage/currents with only operating at fundamental frequency switching. This paper presents a initial level of 5-level up to its giant level 13-level cascaded multilevel converter. In now a days multilevel inverters has become very popular for motor drive applications of industry. Multicarrier pulse width modulation techniques is an effective solution for increases the number of levels of the output wave form and thereby dramatically reduced the harmonics and total harmonic distortion(THD). The output waveform has 5,7,9,11 and 13 levels. In this paper three multicarrier pulse width modulation techniques such as phase shifted, level shifted and the wave level shifted Multi-carrier modulation PWM techniques are discussed. These methods are modeled for all level CMC by using the MATLAB/SIMULINK and the THD of the these methods are compared.
An Improved Repetitive Control for Circulating Current Restraining in MMC-MTDCTELKOMNIKA JOURNAL
The modular multilevel converter (MMC) is widely used in many important application fields such
as high voltage DC transmission system. And the multi-terminal architecture of it attracts many attentions.
However, the circulating current of MMC is an inherent problem which is mainly caused by the voltage
mismatch between arms and DC bus. In this paper, an advanced repetitive control method is proposed.
This method is based on the even-harmonic characteristic of the circulating current and the potential
feature of repetitive control that it has an internal integration part. The pole diagram of the closed loop
transform function of the proposed control system proves the stability of the proposed method. And
according to the simulation results of a three-terminal MMC-MTDC model in PSCAD/EMTDC, the
improved repetitive control presents better circulation repression ability and superior anti-interference
capability by comparing with traditional PI control method. Additionally, the simulation results also indicate
that the proposed repetitive controller can restrain the fluctuation of SM voltage more effectively than PI
control.
Average Phase-Leg Technique on Coupling Impedance Impact Modular Inverter Par...IJMTST Journal
The modular multilevel converter (MMC) is an emerging and highly attractive multilevel converter topology
for high-voltage and high-power applications. This paper proposes the control method of parallel-connected
modular multilevel converters (parallel-MMCs), which assumes that the multiple MMCs are directly connected
at both ac and dc sides to effectively enhance the power rating as expected. Two key problems were first
solved for the parallel-MMCs under the normal operation conditions: voltage balancing of sub modules and
mitigation of circulating currents, where the novel transformed third-order harmonic resonant controller in the
synchronous reference frame was employed to mitigate the dominant second-order and fourth-order
circulating currents and a sixth-order harmonic resonant controller is used to attenuate the zero-sequence
sixth-order circulating current existed in all phase currents per MMC. Considering the high risk of switches
fault in the parallel-MMCs, the fault-tolerant operation schemes were then proposed in this paper to address
the major concerns of open-circuit and short-circuit switch fault in a sub module, respectively. Carefully
controlling the healthy sub modules and the corresponding phase arms, the parallel-MMCs can successfully
maintain their balanced capacitor voltages and mitigate the circulating currents with the qualified output
waveform obtained. In addition, the parallel configuration of MMCs provides the unique solution for the
short-circuit switch fault operation which was seldom discussed in the published literature works with
respect to the MMC fault-tolerant operation schemes. MATLAB simulations and the constructed experimental
prototype have verified the performance of the proposed control strategy.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
TORQUE RIPPLE MINIMIZATION OF MATRIX CONVERTER-FED PMSM DRIVES USING ADVANCED...ijscmcj
An advanced direct torque control (DTC) technique using Model predictive control (MPC) is proposed for matrix converter (MC)-based permanent-magnet synchronous motor (PMSM) drive system, which reduces the torque ripples, does not need the duty cycle calculation, and ensures the fixed switching frequency. Analytical expressions of change rates of torque and flux of PMSM as a function of MC - dqo components are derived. The predictive model of PMSM and MC is realized by means of State model. Then, the advanced MC-fed DTC algorithm is implemented based on Cost function evaluation. The simulation results exhibit remarkable torque ripple reduction with the help of MPC. As a result, the proposed strategy is proved to be effective in minimizing the torque ripples for MC-based PMSM drives.
Investigation of THD for Cascaded Multi-Level Inverter Using Multicarrier Mod...IJERA Editor
A novelty kind of Multilevel converters are used in high voltage and high power application of industry field, can able to produce near sinusoidal voltage/currents with only operating at fundamental frequency switching. This paper presents a initial level of 5-level up to its giant level 13-level cascaded multilevel converter. In now a days multilevel inverters has become very popular for motor drive applications of industry. Multicarrier pulse width modulation techniques is an effective solution for increases the number of levels of the output wave form and thereby dramatically reduced the harmonics and total harmonic distortion(THD). The output waveform has 5,7,9,11 and 13 levels. In this paper three multicarrier pulse width modulation techniques such as phase shifted, level shifted and the wave level shifted Multi-carrier modulation PWM techniques are discussed. These methods are modeled for all level CMC by using the MATLAB/SIMULINK and the THD of the these methods are compared.
An Improved Repetitive Control for Circulating Current Restraining in MMC-MTDCTELKOMNIKA JOURNAL
The modular multilevel converter (MMC) is widely used in many important application fields such
as high voltage DC transmission system. And the multi-terminal architecture of it attracts many attentions.
However, the circulating current of MMC is an inherent problem which is mainly caused by the voltage
mismatch between arms and DC bus. In this paper, an advanced repetitive control method is proposed.
This method is based on the even-harmonic characteristic of the circulating current and the potential
feature of repetitive control that it has an internal integration part. The pole diagram of the closed loop
transform function of the proposed control system proves the stability of the proposed method. And
according to the simulation results of a three-terminal MMC-MTDC model in PSCAD/EMTDC, the
improved repetitive control presents better circulation repression ability and superior anti-interference
capability by comparing with traditional PI control method. Additionally, the simulation results also indicate
that the proposed repetitive controller can restrain the fluctuation of SM voltage more effectively than PI
control.
Average Phase-Leg Technique on Coupling Impedance Impact Modular Inverter Par...IJMTST Journal
The modular multilevel converter (MMC) is an emerging and highly attractive multilevel converter topology
for high-voltage and high-power applications. This paper proposes the control method of parallel-connected
modular multilevel converters (parallel-MMCs), which assumes that the multiple MMCs are directly connected
at both ac and dc sides to effectively enhance the power rating as expected. Two key problems were first
solved for the parallel-MMCs under the normal operation conditions: voltage balancing of sub modules and
mitigation of circulating currents, where the novel transformed third-order harmonic resonant controller in the
synchronous reference frame was employed to mitigate the dominant second-order and fourth-order
circulating currents and a sixth-order harmonic resonant controller is used to attenuate the zero-sequence
sixth-order circulating current existed in all phase currents per MMC. Considering the high risk of switches
fault in the parallel-MMCs, the fault-tolerant operation schemes were then proposed in this paper to address
the major concerns of open-circuit and short-circuit switch fault in a sub module, respectively. Carefully
controlling the healthy sub modules and the corresponding phase arms, the parallel-MMCs can successfully
maintain their balanced capacitor voltages and mitigate the circulating currents with the qualified output
waveform obtained. In addition, the parallel configuration of MMCs provides the unique solution for the
short-circuit switch fault operation which was seldom discussed in the published literature works with
respect to the MMC fault-tolerant operation schemes. MATLAB simulations and the constructed experimental
prototype have verified the performance of the proposed control strategy.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
ENHANCEMENT OF FUNDAMENTAL RMS OUTPUT VOLTAGE OF 5-LEVEL CASCADED H-BRIDGE MU...IAEME Publication
Cascaded H-bridge Multilevel Inverter (CHBMLI) is the most suitable topology for the PV power converters. In this paper an effort has been made to increase the performance of CHBMLI by improving the fundamental Root Mean Square (RMS) value of the output voltage. This work proposes a Modified Multi Carrier PWM (MMCPWM) technique where, reference sine wave has been replaced by ellipse wave, resulting in enhanced performances on the fundamental rms output voltage and lower Total Harmonic Distortion (THD). Analysis of single phase 5-level CHBMLI with and without load are carried for the different Multi Carrier PWM (MCPWM) techniques.
Simplified Space Vector Pulse Width Modulation Based on Switching Schemes wit...IJAAS Team
This paper presents a simplified control strategy of SVPWM with a three segment switching sequence and 7 segment switch frequency for high power multilevel inverter. In the proposed method, the inverter switching sequences are optimized for minimization of device switching sequence frequency and improvement of harmonic spectrum by using the three most derived switching states and one suitable redundant state for each space vector. The proposed 3-segment sequence is compared with conventional 7-segment sequence similar for five level Cascaded H-Bridge inverter with various values of switching frequencies including very low frequency. The output spectrum of the proposed sequence design shows the reduction of device switching frequency and states current and line voltage. THD this minimizing the filter size requirement of the inverter, employed in industrial applications. Where sinusoidal output voltage is required.
Efficiency, reliability, high power quality and continuous operation are important aspects in electric vehicle attraction system. Therefore, quick fault detection, isolation and enhanced fault-tolerant control for open-switches faults in inverter driving systems become more and more required in this filed. However, fault detection and localization algorithms have been known to have many performance limitations due to speed variations such as wrong decision making of fault occurrence. Those weaknesses are investigated and solved in this paper using currents magnitudes fault indices, current direct component fault indices and a decision system. A simulation model and experimental setup are utilized to validate the proposed concept. Many simulation and experimental results are carried out to show the effectiveness of the proposed fault detection approach.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Finite State Predictive Current and Common Mode Voltage Control of a Seven-ph...IAES-IJPEDS
The paper illustrates finite set predictive current control (FSPC) along with
common mode voltage control of a seven-phase voltage source inverter
(VSI). The current and common mode voltage (CMV) controls are done
considering a finite set of control actions. The space vector model of a sevenphase
voltage source inverter produces 27 = 128 space voltage vectors, with
126 active and two zero vectors. Out of 126 space vectors 112 are distinct
and 14 are redundant vectors. To control the current and the common mode
voltage, specific set of space vectors are chosen that minimizes the
magnitude of the CMV and makes it a dc signal and simultaneously track the
reference current. Hence no common mode current can flow. Three sets of
space vectors are used for switching actuation, in one case only 15 vectors
are used (14 active and one zero), in second case 14 vectors are used,
followed by use of 8 space vectors (7 large and one zero) and finally 7 large
vectors are employed. Optimal algorithm is employed to find the vector
which minimizes the chosen cost function. The effect of selecting the cost
function, the number of space vectors on current tracking and common mode
voltage is investigated and reported. The developed technique is tested for
RL load using simulation and experimental approaches.
Model Predictive Current Control of a Seven-phase Voltage Source Inverteridescitation
The paper elaborate finite set model based predictive
current control of a seven-phase voltage source inverter. The
current control is carried out considering a finite set of control
actions. The space vector model of a seven-phase voltage source
inverter (VSI) yields 27 = 128 space voltage vectors, with 126
active and two zero vectors. The control method described in
this paper discard some switching states from the whole set
and employs reduced number of switching states to track the
commanded current. Three sets of space vectors are used for
switching actuation, in one case only 15 vectors are used (14
active and one zero), in second case 29 vectors are used (28
active and one zero) and finally 43 vectors (42 active and one
zero) are employed. Optimal algorithm is employed to find
the vector which minimizes the chosen cost function. The
effect of selecting the cost function, the number of space
vectors and the sampling time is investigated and reported.
The developed technique is tested for RL load using simulation
and experimental approaches.
MODELLING AND IMPLEMENTATION OF AN IMPROVED DSVM SCHEME FOR PMSM DTCpaperpublications3
Abstract: A very widely used drive strategy for PMSM is the field oriented control (FOC), which was proposed in 1971 for induction motors (IMs). However, the FOC scheme is quite complex due to the reference frame transformation and its high dependence upon the motor parameters and speed. To mitigate these problems, a new control strategy for the torque control of induction motor was developed by Takahashi known as the direct torque control (DTC) and by Depenbrock as the direct self control (DSC). The basic direct torque control (DTC) scheme may cause undesired torque, flux and current ripples because of the small number of applicable voltage vectors. The control system should be able to generate any voltage vector, implying the use of space vector modulation (SVM) which complicates the control scheme. The discrete space vector modulation (DSVM) method was proposed for DTC to overcome this problem which replaces the simple switching table by several switching tables, to apply a combination of three voltage vectors in the same sampling period. In this paper, after a brief review of the primary concept of DSVM DTC technique, a new scheme of DSVM DTC for PMSM is proposed with a new set of switching tables taking into account the motor speed and the absolute values of torque and flux feedback errors. In one fixed sampling time interval, three vectors are applied to the motor including the two null vectors. Comparisons of the basic DTC and the improved DSVM DTC schemes are made based on the system performance and switching loss. For this purpose the DSVM technique uses prefixed time intervals within a sampling cycle to synthesize a higher number of voltage vectors than the basic DTC scheme. A set of switching table is carried out to minimize the torque error. An optimal vector selector is developed to reduce the switching loss and make the system more stable. The sampling period does not need to be doubled in order to achieve a mean switching frequency practically equal to that of the basic DTC scheme. For a comparable performance, the switching loss of the proposed scheme is less than that of the basic DTC method. The vector application sequence is investigated and an optimal algorithm is developed to reduce the switching loss and torque ripple. Simulation and experiments on the improved DSVM DTC are carried out and compared with those on the basic DTC scheme.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The Journal of MC Square Scientific Research is published by MC Square Publication on the monthly basis. It aims to publish original research papers devoted to wide areas in various disciplines of science and engineering and their applications in industry. This journal is basically devoted to interdisciplinary research in Science, Engineering and Technology, which can improve the technology being used in industry. The real-life problems involve multi-disciplinary knowledge, and thus strong inter-disciplinary approach is the need of the research.
This paper presents new modified space vector pulse width modulation techniques (Phase disposition-Space vector pulse width modulation, Alternative Phase Opposition disposition- Space vector pulse width modulation and Phase Opposition disposition-Space vector pulse width modulation) are analyzed for three-phase cascaded multi-level inverter fed induction motor from the point of view of the Phase voltages, line voltage, stator current,speed,torque and Total harmonic distortion.in the proposed modified technique the reference signals are generated by adding offset voltage to the reference phase voltages.This modified SVPWM technique does not involve region indentification,sector identification for switching vector determination as are required in the conventional multi level SVPWM technique,it is also reduces the computation time compared to the conventional space vector PWM technique.The necessary calculations for generation of new modified SVPWM for the modulation strategies have presented in detail. It is observed that the modified SVPWM modulation ensures excellent, close to optimized pulse distribution results and THD is compared to for five-level, seven-level, nine-level and eleven-level Cascaded H-Bride Multi-level Inverter fed to Induction motor. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
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.
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
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
State-space averaged modeling and transfer function derivation of DC-DC boost...TELKOMNIKA JOURNAL
This paper presents dynamic analysis of a boost type DC-DC converter for high-brightness LED (HBLED) driving applications. The steady state operation in presence of all system parasitics has been discussed for continuous conduction mode (CCM). The state-space averaging, energy conservation principle and standard linearization are used to derive ac small signal control to inductor current open-loop transfer function of the converter. The derived transfer function can be further used in designing a robust feed-back control network for the system. In the end frequency and transient responses of the derived transfer function are obtained for a given set of component values, hence to provide a useful guide for control design engineers.
Design consideration of an mmc hvdc system based on 4500 v:4000a emitter turn...Ghazal Falahi
Excessive power loss is a major concern in high voltage and high power applications and is considered one of the main drawbacks of VSC-HVDC system when compared with traditional HVDC system based on thyristor technology. This is primarily caused by high switching loss associated with switching devices used in the VSC-HVDC. This issue can be largely addressed by using the emerging MMC-HVDC topology, which requires much lower switching frequency than traditional VSC-HVDC. Emitter turn-off thyristor (ETO) is one of the best high power switching devices packed with many advanced features. ETO thyristor based MMC-HVDC system is therefore an extremely attractive choice for ultra-high voltage and high power HVDCs. This paper discusses the operation principle of ETO based MMC-HVDC as well as its design and loss comparison with other solutions.
Modelling and Simulation of a Sensorless Control of a True Asymmetric Cascade...IJPEDS-IAES
This paper introduces a new method to track the saliency of an AC motor fed
by a multilevel converter through measuring the dynamic current response of
the motor line currents due the IGBT switching actions. The method uses
only the fundamental PWM waveform (i.e there is no modification to the
operation of the multilevel converter) similar to the fundamental PWM
method proposed for a 2-level converter. Simulation results are provided to
demonstrate the performance of the complete sensorless speed control of a
PM motor driven by such a converter over a wide speed range. Finally the
paper introduces a comparison between the 2-level converter and the
multilevel converter in terms of the reduction of the total harmonic distortion
(THD) using the fundamental PWM method in both cases.
A NEW FUZZY LOGIC BASED SPACE VECTOR MODULATION APPROACH ON DIRECT TORQUE CON...csandit
The induction motors are indispensable motor types for industrial applications due to its wellknown
advantages. Therefore, many kind of control scheme are proposed for induction motors
over the past years and direct torque control has gained great importance inside of them due to
fast dynamic torque response behavior and simple control structure. This paper suggests a new
approach on the direct torque controlled induction motors, Fuzzy logic based space vector
modulation, to overcome disadvantages of conventional direct torque control like high torque
ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic
controller and applied by space vector pulse width modulator to voltage source inverter. In
order to test and compare the proposed DTC scheme with conventional DTC scheme
simulations, in Matlab/Simulink, have been carried out in different speed and load conditions.
The simulation results showed that a significant improvement in the dynamic torque and speed
responses when compared to the conventional DTC scheme.
Artificial Neural Network Controller for Reducing the Total Harmonic Distorti...IJAEMSJORNAL
A neural network based space vector modulation (SVM) of voltage source inverter is proposed. The voltage source converter (VSC) is highly used in high voltage direct current (HVDC) transmission so that a detailed analysis and transmission of this system is carried out. In addition, a non-linear neural network controller is proposed to control the space vector pulse width modulation (SVPWM) to reduce the total harmonic distortion (THD) of the converter (inverter) output voltage. The inverter outputcurrent is analyzed with two switching frequency 1050Hz and1450Hz with and without proposed ANN controller. The results show a THD enhancement about 0.74 % for 1050Hz and 0.68 % for 1450Hz.
A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Pe...IJPEDS-IAES
This paper presents a novel method of optimal Propotional-Intergral (PI)
controller’s parameter tuning strategy in-order to improve the constant
switching performance of 3-phase direct torque control (DTC) shceme. The
DTC sheme is acknowledged to provide fast decoupled control over the
torque output and stator flux via a simple control structure. However, DTC
sheme has two major downsides, which are the inconsistent inverter
switching frequency and high torque output ripple. The main reason that
contributes to these tribulations is the usage of hysteresis comparators in
order to control the output torque. The realization of PI based controller
method as replacement of hyterisis controller in DTC system able to provide
significant solutions to over come the fall back while retaining the simple
control structure of conventional DTC. The combination usage of higher
sampling controller DS1004 and also 3-level cascaded H-bridge multilevel
inverters (CHMI) in this system can further minimize the output torque ripple
by providing higher resolution with lower digital error and greater number of
vectors. This paper presents detail explanation and calculation of optimal PI
parameter tuning strategy consecutively to enhance the performance of 3-
level DTC system. In order to verify the feasibility of the proposed method
experimentation, the proposed method is compared with convention DTC
system via simulation and experiment results.
ENHANCEMENT OF FUNDAMENTAL RMS OUTPUT VOLTAGE OF 5-LEVEL CASCADED H-BRIDGE MU...IAEME Publication
Cascaded H-bridge Multilevel Inverter (CHBMLI) is the most suitable topology for the PV power converters. In this paper an effort has been made to increase the performance of CHBMLI by improving the fundamental Root Mean Square (RMS) value of the output voltage. This work proposes a Modified Multi Carrier PWM (MMCPWM) technique where, reference sine wave has been replaced by ellipse wave, resulting in enhanced performances on the fundamental rms output voltage and lower Total Harmonic Distortion (THD). Analysis of single phase 5-level CHBMLI with and without load are carried for the different Multi Carrier PWM (MCPWM) techniques.
Simplified Space Vector Pulse Width Modulation Based on Switching Schemes wit...IJAAS Team
This paper presents a simplified control strategy of SVPWM with a three segment switching sequence and 7 segment switch frequency for high power multilevel inverter. In the proposed method, the inverter switching sequences are optimized for minimization of device switching sequence frequency and improvement of harmonic spectrum by using the three most derived switching states and one suitable redundant state for each space vector. The proposed 3-segment sequence is compared with conventional 7-segment sequence similar for five level Cascaded H-Bridge inverter with various values of switching frequencies including very low frequency. The output spectrum of the proposed sequence design shows the reduction of device switching frequency and states current and line voltage. THD this minimizing the filter size requirement of the inverter, employed in industrial applications. Where sinusoidal output voltage is required.
Efficiency, reliability, high power quality and continuous operation are important aspects in electric vehicle attraction system. Therefore, quick fault detection, isolation and enhanced fault-tolerant control for open-switches faults in inverter driving systems become more and more required in this filed. However, fault detection and localization algorithms have been known to have many performance limitations due to speed variations such as wrong decision making of fault occurrence. Those weaknesses are investigated and solved in this paper using currents magnitudes fault indices, current direct component fault indices and a decision system. A simulation model and experimental setup are utilized to validate the proposed concept. Many simulation and experimental results are carried out to show the effectiveness of the proposed fault detection approach.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Finite State Predictive Current and Common Mode Voltage Control of a Seven-ph...IAES-IJPEDS
The paper illustrates finite set predictive current control (FSPC) along with
common mode voltage control of a seven-phase voltage source inverter
(VSI). The current and common mode voltage (CMV) controls are done
considering a finite set of control actions. The space vector model of a sevenphase
voltage source inverter produces 27 = 128 space voltage vectors, with
126 active and two zero vectors. Out of 126 space vectors 112 are distinct
and 14 are redundant vectors. To control the current and the common mode
voltage, specific set of space vectors are chosen that minimizes the
magnitude of the CMV and makes it a dc signal and simultaneously track the
reference current. Hence no common mode current can flow. Three sets of
space vectors are used for switching actuation, in one case only 15 vectors
are used (14 active and one zero), in second case 14 vectors are used,
followed by use of 8 space vectors (7 large and one zero) and finally 7 large
vectors are employed. Optimal algorithm is employed to find the vector
which minimizes the chosen cost function. The effect of selecting the cost
function, the number of space vectors on current tracking and common mode
voltage is investigated and reported. The developed technique is tested for
RL load using simulation and experimental approaches.
Model Predictive Current Control of a Seven-phase Voltage Source Inverteridescitation
The paper elaborate finite set model based predictive
current control of a seven-phase voltage source inverter. The
current control is carried out considering a finite set of control
actions. The space vector model of a seven-phase voltage source
inverter (VSI) yields 27 = 128 space voltage vectors, with 126
active and two zero vectors. The control method described in
this paper discard some switching states from the whole set
and employs reduced number of switching states to track the
commanded current. Three sets of space vectors are used for
switching actuation, in one case only 15 vectors are used (14
active and one zero), in second case 29 vectors are used (28
active and one zero) and finally 43 vectors (42 active and one
zero) are employed. Optimal algorithm is employed to find
the vector which minimizes the chosen cost function. The
effect of selecting the cost function, the number of space
vectors and the sampling time is investigated and reported.
The developed technique is tested for RL load using simulation
and experimental approaches.
MODELLING AND IMPLEMENTATION OF AN IMPROVED DSVM SCHEME FOR PMSM DTCpaperpublications3
Abstract: A very widely used drive strategy for PMSM is the field oriented control (FOC), which was proposed in 1971 for induction motors (IMs). However, the FOC scheme is quite complex due to the reference frame transformation and its high dependence upon the motor parameters and speed. To mitigate these problems, a new control strategy for the torque control of induction motor was developed by Takahashi known as the direct torque control (DTC) and by Depenbrock as the direct self control (DSC). The basic direct torque control (DTC) scheme may cause undesired torque, flux and current ripples because of the small number of applicable voltage vectors. The control system should be able to generate any voltage vector, implying the use of space vector modulation (SVM) which complicates the control scheme. The discrete space vector modulation (DSVM) method was proposed for DTC to overcome this problem which replaces the simple switching table by several switching tables, to apply a combination of three voltage vectors in the same sampling period. In this paper, after a brief review of the primary concept of DSVM DTC technique, a new scheme of DSVM DTC for PMSM is proposed with a new set of switching tables taking into account the motor speed and the absolute values of torque and flux feedback errors. In one fixed sampling time interval, three vectors are applied to the motor including the two null vectors. Comparisons of the basic DTC and the improved DSVM DTC schemes are made based on the system performance and switching loss. For this purpose the DSVM technique uses prefixed time intervals within a sampling cycle to synthesize a higher number of voltage vectors than the basic DTC scheme. A set of switching table is carried out to minimize the torque error. An optimal vector selector is developed to reduce the switching loss and make the system more stable. The sampling period does not need to be doubled in order to achieve a mean switching frequency practically equal to that of the basic DTC scheme. For a comparable performance, the switching loss of the proposed scheme is less than that of the basic DTC method. The vector application sequence is investigated and an optimal algorithm is developed to reduce the switching loss and torque ripple. Simulation and experiments on the improved DSVM DTC are carried out and compared with those on the basic DTC scheme.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The Journal of MC Square Scientific Research is published by MC Square Publication on the monthly basis. It aims to publish original research papers devoted to wide areas in various disciplines of science and engineering and their applications in industry. This journal is basically devoted to interdisciplinary research in Science, Engineering and Technology, which can improve the technology being used in industry. The real-life problems involve multi-disciplinary knowledge, and thus strong inter-disciplinary approach is the need of the research.
This paper presents new modified space vector pulse width modulation techniques (Phase disposition-Space vector pulse width modulation, Alternative Phase Opposition disposition- Space vector pulse width modulation and Phase Opposition disposition-Space vector pulse width modulation) are analyzed for three-phase cascaded multi-level inverter fed induction motor from the point of view of the Phase voltages, line voltage, stator current,speed,torque and Total harmonic distortion.in the proposed modified technique the reference signals are generated by adding offset voltage to the reference phase voltages.This modified SVPWM technique does not involve region indentification,sector identification for switching vector determination as are required in the conventional multi level SVPWM technique,it is also reduces the computation time compared to the conventional space vector PWM technique.The necessary calculations for generation of new modified SVPWM for the modulation strategies have presented in detail. It is observed that the modified SVPWM modulation ensures excellent, close to optimized pulse distribution results and THD is compared to for five-level, seven-level, nine-level and eleven-level Cascaded H-Bride Multi-level Inverter fed to Induction motor. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
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.
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
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
State-space averaged modeling and transfer function derivation of DC-DC boost...TELKOMNIKA JOURNAL
This paper presents dynamic analysis of a boost type DC-DC converter for high-brightness LED (HBLED) driving applications. The steady state operation in presence of all system parasitics has been discussed for continuous conduction mode (CCM). The state-space averaging, energy conservation principle and standard linearization are used to derive ac small signal control to inductor current open-loop transfer function of the converter. The derived transfer function can be further used in designing a robust feed-back control network for the system. In the end frequency and transient responses of the derived transfer function are obtained for a given set of component values, hence to provide a useful guide for control design engineers.
Design consideration of an mmc hvdc system based on 4500 v:4000a emitter turn...Ghazal Falahi
Excessive power loss is a major concern in high voltage and high power applications and is considered one of the main drawbacks of VSC-HVDC system when compared with traditional HVDC system based on thyristor technology. This is primarily caused by high switching loss associated with switching devices used in the VSC-HVDC. This issue can be largely addressed by using the emerging MMC-HVDC topology, which requires much lower switching frequency than traditional VSC-HVDC. Emitter turn-off thyristor (ETO) is one of the best high power switching devices packed with many advanced features. ETO thyristor based MMC-HVDC system is therefore an extremely attractive choice for ultra-high voltage and high power HVDCs. This paper discusses the operation principle of ETO based MMC-HVDC as well as its design and loss comparison with other solutions.
Modelling and Simulation of a Sensorless Control of a True Asymmetric Cascade...IJPEDS-IAES
This paper introduces a new method to track the saliency of an AC motor fed
by a multilevel converter through measuring the dynamic current response of
the motor line currents due the IGBT switching actions. The method uses
only the fundamental PWM waveform (i.e there is no modification to the
operation of the multilevel converter) similar to the fundamental PWM
method proposed for a 2-level converter. Simulation results are provided to
demonstrate the performance of the complete sensorless speed control of a
PM motor driven by such a converter over a wide speed range. Finally the
paper introduces a comparison between the 2-level converter and the
multilevel converter in terms of the reduction of the total harmonic distortion
(THD) using the fundamental PWM method in both cases.
A NEW FUZZY LOGIC BASED SPACE VECTOR MODULATION APPROACH ON DIRECT TORQUE CON...csandit
The induction motors are indispensable motor types for industrial applications due to its wellknown
advantages. Therefore, many kind of control scheme are proposed for induction motors
over the past years and direct torque control has gained great importance inside of them due to
fast dynamic torque response behavior and simple control structure. This paper suggests a new
approach on the direct torque controlled induction motors, Fuzzy logic based space vector
modulation, to overcome disadvantages of conventional direct torque control like high torque
ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic
controller and applied by space vector pulse width modulator to voltage source inverter. In
order to test and compare the proposed DTC scheme with conventional DTC scheme
simulations, in Matlab/Simulink, have been carried out in different speed and load conditions.
The simulation results showed that a significant improvement in the dynamic torque and speed
responses when compared to the conventional DTC scheme.
Artificial Neural Network Controller for Reducing the Total Harmonic Distorti...IJAEMSJORNAL
A neural network based space vector modulation (SVM) of voltage source inverter is proposed. The voltage source converter (VSC) is highly used in high voltage direct current (HVDC) transmission so that a detailed analysis and transmission of this system is carried out. In addition, a non-linear neural network controller is proposed to control the space vector pulse width modulation (SVPWM) to reduce the total harmonic distortion (THD) of the converter (inverter) output voltage. The inverter outputcurrent is analyzed with two switching frequency 1050Hz and1450Hz with and without proposed ANN controller. The results show a THD enhancement about 0.74 % for 1050Hz and 0.68 % for 1450Hz.
A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Pe...IJPEDS-IAES
This paper presents a novel method of optimal Propotional-Intergral (PI)
controller’s parameter tuning strategy in-order to improve the constant
switching performance of 3-phase direct torque control (DTC) shceme. The
DTC sheme is acknowledged to provide fast decoupled control over the
torque output and stator flux via a simple control structure. However, DTC
sheme has two major downsides, which are the inconsistent inverter
switching frequency and high torque output ripple. The main reason that
contributes to these tribulations is the usage of hysteresis comparators in
order to control the output torque. The realization of PI based controller
method as replacement of hyterisis controller in DTC system able to provide
significant solutions to over come the fall back while retaining the simple
control structure of conventional DTC. The combination usage of higher
sampling controller DS1004 and also 3-level cascaded H-bridge multilevel
inverters (CHMI) in this system can further minimize the output torque ripple
by providing higher resolution with lower digital error and greater number of
vectors. This paper presents detail explanation and calculation of optimal PI
parameter tuning strategy consecutively to enhance the performance of 3-
level DTC system. In order to verify the feasibility of the proposed method
experimentation, the proposed method is compared with convention DTC
system via simulation and experiment results.
The study made in this paper concerns the use of the voltage-oriented control (VOC) of three-phase pulse width modulation (PWM) rectifier with constant switching frequency. This control method, called voltage-oriented controlwith space vector modulation (VOC-SVM). The proposed control scheme has been founded on the transformation between stationary (α-β) and and synchronously rotating (d-q) coordinate system, it is based on two cascaded control loops so that a fast inner loop controls the grid current and an external loop DC-link voltage, while the DC-bus voltage is maintained at the desired level and ansured the unity power factor operation. So, the stable state performance and robustness against the load’s disturbance of PWM rectifiers are boths improved. The proposed scheme has been implemented and simulated in MATLAB/Simulink environment. The control system of the VOC-SVM strategy has been built based on dSPACE system with DS1104 controller board. The results obtained show the validity of the model and its control method. Compared with the conventional SPWM method, the VOC-SVM ensures high performance and fast transient response.
Analysis of harmonics and resonances in hvdc mmc link connected to AC gridBérengère VIGNAUX
High-frequency responses of HVDC-MMC links are essential to study because harmonic and resonance phenomena may impact the AC grid. In this paper, EMT-type simulations are used to analyze converter station’s frequency response.
Experiment based comparative analysis of stator current controllers using pre...journalBEEI
The stator current control loop plays an important role in ensuring the quality of electric drives interm of producing fast and adequate required torque. When the current controller provides ideal responses, speed control design subsequently is in charge of improving the system performances. Classical PID control is commonly used in current loop design, this paper presents the comparative analysis of current stator controller using proportional integral control and predictive current control (PCC) in field-oriented control-based induction motor drives, with rigidly coupled loads. The experimental results show system responses with PID and PCC. Informative experiment-based analysis provides primary guidance in selection between the two controls.
OPTIMAL TORQUE RIPPLE CONTROL OF ASYNCHRONOUS DRIVE USING INTELLIGENT CONTROL...elelijjournal
The dynamic performance of an asynchronous machine when operated with cascaded Voltage Source Inverter using Space Vector Modulation (SVM) technique is presented in this paper. A classical model of Induction Motor Drive based on Direct Torque Control (DTC) method is considered which displays
appreciable run-time operation with very simple hysteresis control scheme. Direct control of the torque and flux variables is achieved by choosing suitable inverter voltage space vector from a lookup table. Under varying torque conditions the performance of the drive system is verified using MATLAB/Simulink software tool. The ripple content in the torque parameter is significant when traditional PI controller and Fuzzy approach are configured in the proposed system. Finally, by replacing the PI-Fuzzy controller with Hybrid Controller the torque ripple minimization can be achieved during no-load and loaded conditions.
Modelling and Simulation of Three Level VSI-Neutral Point Balancing -Fed AC D...IJERA Editor
Multilevel inverter topology has developed recently as a very important alternative in the area of high power
medium voltage energy control. In multilevel inverter, thethree basic types of topologies used are diode clamped
inverter (neutral point clamped), capacitorclamped (flying capacitor) and cascaded multi cell with separate dc
sources. Multilevel inverters are used in medium voltage and high power applications with less harmonic
contents. This paper proposes a software implementation of neutral point clamped (NPC) three level voltage
source inverter using space vector pulse width modulation (SVPWM) techniques. The inverter feeds an
electrical system which is controlled by field oriented control (FOC).The improvement of the control technique
is achieved using intelligence techniques. The operation of the electrical system is verified in steady state and
transient state responses. This software implementation is performed by using matlab/Simulink software. This
paper gives comparison between SVPWM three phase three level with neutral point clamped and without
neutral point clamped. Finally, the comparative study of different techniques was implemented.
This paper proposes the grid application of modified three-phase topology of Modular Multilevel Converter (MMC) using finite-control-set predictive control. This topology has reduced number of switch counts compared to the conventional MMC, eliminates the problem of circulating current and having higher efficiency. A single dc source is required to produce sinusoidal outputs. The number of sub-modules (SMs) in this topology is half of the SMs required in case of MMC, in addition to a single H-bride circuit per phase. The finite-control-set predictive current control scheme for the grid connected dc source through the Hybrid Modular Multilevel Converter (HMMC). This controller controls the desired real and reactive power demand of the grid instantaneously. The simulation study of a three phase grid connected system has been done in Matlab/Simulink and the results are provided for the different real and reactive power demands, to validate the concepts.
The induction motors are indispensable motor types for industrial applications due to its wellknown advantages. Therefore, many kind of control scheme are proposed for induction motors over the past years and direct torque control has gained great importance inside of them due to fast dynamic torque response behavior and simple control structure. This paper suggests a new approach on the direct torque controlled induction motors, Fuzzy logic based space vector
modulation, to overcome disadvantages of conventional direct torque control like high torque ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic
controller and applied by space vector pulse width modulator to voltage source inverter. In order to test and compare the proposed DTC scheme with conventional DTC scheme
simulations, in Matlab/Simulink, have been carried out in different speed and load conditions. The simulation results showed that a significant improvement in the dynamic torque and speed responses when compared to the conventional DTC scheme.
Temporary voltage swells and sags appear with high frequency in electric power systems, and they significantly affect sensitive loads such as industrial manufacturing or communication devices. This paper presents a strategy to design proportional-resonant controllers for three full-bridge voltage-source converters with a common DC-link in dynamic voltage restorer systems. The proposed controllers allow the system to quickly overcome temporary unbalanced voltage sags. Simulation results carried out in MATLAB/Simulink and experimental results implemented in a Typhoon HIL402 device demonstrate the ability of the proposed design method. The results show that the system with the proposed controllers can ride-through single-phase or double-phase voltage sags up to 55% and three-phase voltage sags up to 70% in a duration less than one grid-voltage cycle.
In this paper, a new topology of Adaptive Hysteresis Band controller for Boost & Buck converter has been proposed, modeled and analyzed. The difficulties caused in Hysteresis Band (HB) controlled dc-dc converter have been eliminated using Adaptive Hysteresis Band (AHB) controller. This novel control topology can be able to maintain the switching frequency constant unlike HB controller. Thus the filter design for the converters will become easier with this controller. Again this control methodology is a robust one as it depends upon the system parameters where there was no possibility with HB controller. The Mathematical modeling of the controller is shown in this paper, further this has been simulated using Matlab /SIMULINK to generate pulse. The steady state analysis to find the parameters and the stability condition of the converter using the dynamic behavior is also portrayed in this paper. The simulation for a Boost and a Buck converter is also shown separately using AHB controller.
In this article, we have proposed a new control of a PV system connected to the grid. The goal is
to reduce current and voltage harmonicsfor increasing the quality of delivered energy. First, we have
modeled a PV panel. Then we have dimensioned the BOOST converter by finding L and C values. Next,
we have used Perturb and Observe (P&O) Maximum Power Point Control (MPPT) to improve energy
efficiency. Finally, We have developed a control of single-phase H-bridge inverter in order to eliminate the
3rd,5th,7th and 9th harmonics order, and added an LCLTo connect the PV inverter to the grid, an LCL
betweenthe inverter and the grid. Theperformance of the proposed system was tested by computing
spectrum and THD usingMatlab/Simulink software. The proposed architecture provides better Total
Harmonic Distortion (THD) which satisfy the EN50160 requirement the THD must be less than 4.66%. We
found that THD was decreased from 61.93% to 0.04%.
Three-Level DTC Based on Fuzzy Logic and Neural Network of Sensorless DSSM Us...IJPEDS-IAES
This paper presents a direct torque control is applied for salient-pole double star synchronous machine without mechanical speed and stator flux linkage sensors. The estimation is performed using the extended Kalman filter known by it is ability to process noisy discrete measurements. Two control approaches using fuzzy logic DTC, and neural network DTC are proposed and compared. The validity of the proposed controls scheme is verified by simulation tests of a double star synchronous machine. The stator flux, torque, and speed are determined and compared in the above techniques. Simulation results presented in this paper highlight the improvements produced by the proposed control method based on the extended Kalman filter under various operation conditions.
Optimization techniques for harmonics minimization in cascaded hybrid multile...eSAT Journals
Abstract
Recent advancements in the field of power electronics have made possible the worldwide application of converters in dc power source utilization, uninterruptible power supplies, electric motor speed control, switched mode power supplies, flexible alternating current transmission systems devices including static synchronous compensator and their controls. Power semiconductor devices such as converters have been emerged as powerful devices in the power industries. As such, harmonics free output of inverters is assuming extreme importance. Over the past decades, depending upon the topologies and control strategies, numerous optimization techniques have been proposed for desired output waveform. This paper presents a review of optimization techniques used for multilevel inverters. The pros and cons of optimization techniques are discussed. The objective of these optimization techniques is to find out the optimum firing angles of multilevel inverters, which results in minimum harmonics. As a preferred option for proposed work, reduction of total harmonic distortion with the aid of particle swarm optimization technique to multilevel inverters is suggested.
Keywords: Power Converters, Multilevel Inverters (MLI), Cascaded Hybrid Bridge (CHB), Modulation, Switching Frequency, Harmonic Distortions.
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[9_CV] FCS-Model Predictive Control of Induction Motors feed by MultilLevel Casaded H-Bridge Inverter
1. 36
FCS-Model Predictive Control of Induction Motors
feed by MultilLevel Cascaded H-Bridge Inverter
Ha Thanh Vo
University of transport and
communications
Ha Noi, Viet Nam
vothanhha.ktd@utc.edu.vn
Minh Trong Tran
Ha Noi university of science and
technology
Ha Noi, Viet Nam
minh.trantrong@hust.edu.vn
Nam Thanh Hoang
Ha Noi university of science and
technology
Ha Noi. Viet Nam
thanhnambka@gmail.com
Dich Quang Nguyen
Ha Noi university of science and
technology
Ha Noi, Viet Nam
dich.nguyenquang@hust.edu.vn
Phuong Hoang Vu
Ha Noi university of science and
technology
Ha Noi, Viet Nam
phuong.vuhoang@hust.edu.vn
Abstract— This paper presents a finite control set – model
predictive control (FCS-MPC) of induction motor fed by a
multilevel cascaded H-bridge inverter. The control scheme has
been based on discretized model of the IM motor and also on
the discrete nature of power electronic converter. In each
predict time period the optimization procedure estimates cost
function under a finite control set which is among the most
effective switching voltage vectors of the multilevel converter.
To ease the future experimental prototype building, this work
has purposely developed a MPC algorithm for 2 step
prediction time and the IM fed by a 3-levels cascaded H-bridge
inverter. The simulation results show all good attractive
performance and potential implementation.
Keywords— model prediction control (MPC), three level-
inverter, Cascaded H-bridge, induction motor, FCS-MPC
I. INTRODUCTION (HEADING 1)
Nowadays, Field-Oriented-Control (FOC) and Direct
Torque Control (DTC) are the most popular control
strategies of the induction motor (IM). FOC is a technique
which provides a method of decoupling the air-gap flux and
the other producing the electromagnetic torque. Therefore, it
provides independent control of torque and flux, similar to a
separately excited DC machine. DTC is a control method
without a coordinate transformation [4], [5]. DTC offers an
excellent torque response using a less parameter sensitive
model than FOC. For the last decade as an alternative
control strategy come out is the model predictive control
(MPC).
The basic idea of MPC is to pre-calculate the optimum
values for the actuating variables based on a mathematical
model of the system, the history of past control actions and
an optimization of a cost function over a receding prediction
horizon [6]. MPC has many advantages: the basic concept is
easy to understand, the algorithm is simple to implement, it
can handle multi-variable systems and constraints can be
included. The main disadvantage of MPC is the big online
calculation effort, especially with long horizons [7].
Fortunately, the modern digital signal processing (DSP) and
the Field Programmable Gate Arrays (FPGAs) have made it
possible to use MPC in fast dynamic processes such as
power electronics and control of electrical drives [8], [9],
[10] and [11]. Therefore, different applications in voltage
source inverter with predictive control has been successfully
investigated in recent few years, such as a predictive current
control fed by voltage source inverter [12]; predictive torque
and flux control of IM fed by indirect matrix converter
(IMC) with unity power factor control at the input side [13];
multilevel inverter fed induction motor predictive control
[14]; predictive current control of a three-phase four-leg
inverter [15]; torque ripple reduction of IM with predictive
direct torque control method [16], and a weighting factor
optimization method in the predictive control algorithm for
reduction of torque ripple [17], [18].
Especially, the studies on multilevel cascaded H-bridge
inverters for induction motor are of great interest, because
multilevel inverter could increase number of voltage levels,
higher voltage can be generated using the devices of lower
rating, lower switching frequency while producing better
voltage waveform and reduced total harmonic distortion
(THD). The last characteristics are of vital importance for
the operations in high voltage, high power range. In this
work a FCS-MPC technique has been proposed to control
induction motor flux and torque accurately. The control
procedure is to minimize the cost functions for all possible
switching states and to select the optimal state vector for the
next sampling period.
This paper is organized in the following manner: the second
section describes the modeling of the induction motor, three-
level cascaded H- bridge inverter; the third the model
predictive control of induction motor with delay time
compensations, consideration of long prediction horizons for
determination of the predicted variables in the second next
(k+2) sampling time instant, an overall quality function of
the MPC method, and a comprehensive predictive control
scheme. In the fourth section, the simulation results are
discussed to prove the feasibility of the proposed method.
The last section is concluded with a comprehensive
conclusion.
II. SYTEM DESCRIPTION
A. Modeling of induction motor
The induction motor (IM) can be modeled with the
following. The and axes stator voltages of IM are
derived as the sum of the resistive voltage drop and the
derivative of the stator flux linkages in the stationary
reference frame as.
;0
;
s s s s s r r r r r
s s m r r r m s
p
s r
u R i L R i L jz
L i L i L i L i
(1)
Where s
i : stator current; r
i : rotor current; s
R : stator
resistance; r
R : rotor resistance; : rotor angular
2. 37
frequency; pz : number of pole pair; ,s r
L L : self –
inductances; m
L : mutual inductance
The developed electrical torque in the IM can be represented
by stator current and stator flux as the following equation:
3
( )
2
e p s s
T z xi (2)
B. Multi-level voltage source inverter
The cascaded H-Bridge (CHB) multilevel inverter is
frequently studied for command improvement involving
synchronization strategy and output voltage power levels
enhancement. It has a modular structure that produces a stair
wave voltage output from a multitude of DC sources.
The number of voltage levels in a CHB inverter can be
found from:
m=(2H+1) (3)
Where: H is the number of H-bridge cell per phase leg.
The voltage level m is always an odd number for the CHB
inverter while in other multilevel topologies such as diode-
clamped inverter, it can be either an even or odd number.
The total number of active switches (IGBT) used in the
CHB inverter can be calculated by
Nsw= 6(m-1) (4).
In the article we present at a three level H-bridge multilevel
with three separated DC sources with unequal voltage
levels. The inverter is capable of creating three levels of
output voltage (Fig.1), to apply the proposed method.
ZA
ZB
ZC
A
B
C
Z
N
vZN
C
Vdc1
S2
vac
S4
S1 S3
+
-
C
Vdc2
S2
vac
S4
S1 S3
+
-
C
Vdc3
S2 S4
S1 S3
+
-
vac
ia
ib
ic
Fig. 1. Simplified circuit diagram of three-level cascaded H-Bridge
inverter
Fig.1 can express three types of switching states, by
considering all of the three-phase switching states, a total of
27 switching states can be combined. The operating status of
the switch and the pole voltage in the three-level inverter
can be represented by the switching states shown in Table I.
Table I in the symbol is “1” is ‘’ON’ switching state and “0”
is ‘’OFF’ switching state. State level as the following
equation (3):
0 0
1
1
A
ac dc A
dc A
s
v V s
V s
(3)
TABLE I. OPERATING STATUS OF THE SWITCH AND POLE VOLTAGE
State switch State level
S1 S2 S3 S4 Vac State level (SA)
1 1 0 1 0 0 0
2 1 0 0 1 VDC 1
3 0 1 1 0 -VDC -1
4 0 1 0 1 0 0
(1,-1,-1)
V7
(1,1,-1)
V9
(-1,1,-1)
V11
(-1,1,1)
V13
(-1,-1,1)
V15
(1,-1,1)
V17
(0,-1,-1)
(1,0,0)
V1
(1,1,0)
(0,0,-1)
V2
(-1,0,-1)
(0,-1,0)
V3
(0,1,1)
(-1,0,0)
V4
(-1,-1,0)
(0,0,1)
V5
(1,0,-1)
(0,1,0)
V6
(1,0,-1)
V8
(0,1,-1)
V10
(-1,1,0)
V12
(-1,0,1)
V14
(0,-1,1)
V16
(1,-1,0)
V18
(0,0,0)
V0
21
1
3
4
2
Fig. 2. Vector diagram and sectors of the three-level inverter
Fig. 2 shows the vector diagram and sectors of three-level
inverter. Generally, the voltage vector of the three-level can
be largely divided into 6 sectors and each sector can be
divided into 6 segments. In the three-level, when expressing
the reference voltage vector, the sector and segment where
the reference voltage vector is located is designated, and, by
calculating the effective time of the three active vectors that
are most closely located to the reference voltage vector, the
reference voltage vector is generated through the switching
method. Note that there are 6 pairs of nonzero identical
voltage vectors which can be generated using two different
switch states and the zero vector can be made using 3
different switch states. Therefore,19 different voltage vectors
can be generated by the use of the 3-level inverter. The
effects of voltage vectors on the balance of capacitor
voltages are illustrated.
III. PREDITIVE CURRENT CONTROL
A. The required signal estimations
Based on the squired-cage induction machine model
presented in section II, the relationship among stator flux,
rotor flux can be expressed as [16]:
r
r m
m
m s
r
d
T L
dt
L
L L
L
r s
r s
s s
ψ
ψ i
ψ i
ψ i
(5)
Where /r r r
T L R
To discretize (5), the Euler backward approximation [18]:
3. 38
( ) ( 1)
s
dx x k x k
dt T
(6)
( ) . ( 1) ( )
.
1
mr
rr s r
s
LL
k k k
L T R
T
r r s
Ψ Ψ i (7)
where sT :sampling time
Substituting (7) into (5), the discrete equation for the stator
flux can be obtained:
( ) ( ) ( )s r sk k L kk r s
Ψ Ψ i (8)
Where:
2
/ ; 1 ( / )r m r m s r
k L L L L L
B. Discrete-time model predictive current
From the induction machine model presented in section II,
the current stator can be expressed as:
1 1
( ( ) ) )s
s r r s
r
di
i L k j u
R dt T
(9)
To discretize (9), the Euler backward, then, the discrete
equation for the current can be obtained as follows:
( 1) 1 ( )
1 1
( ) . ( ) ( )
s
s
r
r
T
k k
T
k j k k k
R
s s
r s
i i
Ψ v
(10)
Predictive stator current and torque in the next (k+2)th sampling
time instant become as follows: [16]
(1( 2) ) ( 1)
1
[ (( ) ( 1) ( )))
s
s r
r m r s
s r
u
T
k i k
T k
k j k k
T r
i
(11)
The predictive control scheme and algorithm for induction
motor control are presented in Fig.3 and Fig.4, respectively.
Known Speed, Ref. Current
Rotor flux
Prediction of Current and Rotor flux at (k+2)th
Sampling time
Cost function Calculation
For, i = 1:19
i > 19
Selection of Optimum Switching State
Yes
No
Fig. 3. Predictive control algorithm
In Fig.4. Firstly, the rotor speed and stator currents are
measured. Then the rotor flux vector is estimated. Its angle,
together with the torque and flux producing currents
components
*
d
i and
*
qi is used for stator current calculation
in stationary frame. After that, current predictions with
respect to all available voltage vectors will be made. These
predictions are substituted into the cost function, and the
prediction which minimizes the cost function is treated as
the optimal and its corresponding voltage vector used as the
applied vector for the electric drives in the next control
cycle.
The quality function in the predictive control of IM with
delay compensation is presented as below [17]
2 2
2 2
( ) ( 2) ( ) ( 1)J k k k k
* *
s s s s
i i i i (12)
Where :
2 2 2* * *
1 12
... p p
a a a a a a
*
( )si k : reference current predictive variables at k time;
*
2( )si k : reference current predictive variables at k+ 2
4. 39
Cost function
optimization
*
*
di
IM
rψ
Speed
controller
( 2)ksi
dq
( )k*
si
*
qi
si
+
-
+
-
+
-
IE
Cost function
optimization
Vdc3 Vdc2 Vdc1
S2 S1
S4 S3
Vac
iaib
A
B
ic
C
S2 S1
S4 S3
S2 S1
S4 S3
VacVac
N
C C C
; ;a cbS S S
Current
prediction for
(k+2)th sampling
time
Flux estimation
sαi
sβi
Fig. 4. Block diagram of the induction based on MPC using three-level cascaded H-Bridge inverter
IV. SIMULATION RESULTS
TABLE II. DESIGN SPECIFICATION OF INDUCTION MOTOR
Rated power dmP 2.2kW
Rated Torque dmM 7.3Nm
Rated phase current dmI 4.7A
Rated phase voltage dmU 400V
Rated frequency dmf 50Hz
Number of pole pairs p 1
Stator resistance sR 1.99
Rotor resistance rR 1.84
Mutual inductance mL 0.37
Rated speed dmn 2880 rpm
Torque of inertia J 2
.Kg m
Some of the typical working modes of the IMSR are
investigated through the following simulation scenario:
At t = 0s, the magnetization process.
At t = 0.5s, acceleration to the nominal value 150 rad/s.
At t = 0.5s, connection of nominal load (full load).
At t = 1 s, reversing process down to -150 rad/s
The Figs. 5 and 6 represent the results of IM control applied
with model predictive control (MPC) method at high speed
and low speed regions, respectively. Simulation results
show that both the flux forming and torque forming currents
accurately follow the set point trajectories (coming from the
magnetic flux controller and the speed controller in the outer
loop) in all working modes (Fig 5 and Fig 6).
Fig. 5. Current response
*
sd sdi i
5. 40
0 0.5 1 1.5 2 2.5 3
Time [s]
-10
-5
0
5
10
(A)
i*sq: reference current
isq: measured current
Fig. 6. Current response
*
sq sqi i
When the reference speeds have been changed to negative
direction, the measured speeds are started to follow the
reference speeds at exact time of 0.5s and 1s at high and low
speed, respectively, with reverse high torque between +10
and -10.0 Nm at 150 rad and -150 rad/s in both the analysis.
The torque can be generated quickly and the speed in a short
time brought exactly to the set point (0.18s for the run-up
and 0.2s for reversing) Fig 7 and Fig 8.
0 0.5 1 1.5 2 2.5 3
Time [s]
-200
-100
0
100
200
(rad/s)
w*: reference speed
w: measured speed
Fig. 7. Speed response w*- w
0 0.5 1 1.5 2 2.5 3
Time[s]
-20
-10
0
10
20
(N/M)
Te*: reference torque
Te:measured torque
10 N/m load
Fig. 8. Toquer response Te*- Te
Fig.9 observes the three phase stator currents at steady state
with rated speed and torque. The stator current waveforms
are sine. It proves that at the rated condition, the controlled
AC motor with MPC method operates smoothly with a set
of balance three phase currents. And the stator flux
magnitude is kept at a constant.
0 0.5 1 1.5 2 2.5 3
Time [s]
-10
-5
0
5
10
(A)
ia
ib
ic
Fig. 9. Three phase stator current response
By subdividing the voltage vectors of the selected area, the
function is calculated for each voltage vector, and the
minimum value is selected in order to make the final
decision of the reference voltage vector. Finally, the selected
reference voltage vector is used for the control of the three-
level switch through FCS-MPC method (Fig.10).
0 0.5 1 1.5 2 2.5 3
Time [s]
-1000
-500
0
500
1000
(V)
Van: voltage
Fig. 10. Van phase voltage response
The harmonic spectrum of stator current at 150 rad/s with
load is shown Fig.11. The total harmonic distortion (THD)
values measured after the development of the system is
tabulated to analyze the efficiency or result obtained. The
THD is mainly concentrated on the stator phase output
current. The harmonics present in the three phases are so
found form the simulation done. The result obtained proves
that the distortion in the system is less. The current THD of
the MPC is only 1.25%.
Fig. 11. FFT of A phase stator current
6. 41
V. CONCLUSION
In this paper, FCS-MPC controller is proposed and
applied in an induction machine control system with high
power and voltage fed by multilevel-cascaded H-bridge
inverter. The proposed delay time compensated model
predictive control method utilizes the discrete with the
second next (k+2)th predictive variables are predicted. The
delay time has no effect on control performance when delay
time compensation has been taken in consideration in the
predictive control algorithm which results in well tracking of
the reference variables at high speed, even at low speed
regions of the induction motor. It is performance of electric
drive will be improved.
ACKNOWLEDGMENT
The authors are thankful to AUN/SEED-Net for financial
support
This paper is granted by the ĐTĐLCN.44/16 project.
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