EPE Association: EPE 2014 - DS1b: Standard and Advanced Control Techniques for Power Converters

EPE 2014 - DS1b: Standard and Advanced Control Techniques for Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2014 ECCE Europe - Conference > EPE 2014 - Topic 03: Measurement and Control > EPE 2014 - DS1b: Standard and Advanced Control Techniques for Power Converters

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   A General Wireless Strategy for Load Sharing Among Dissimilar Paralleled Inverters
By Ebrahim FARJAH, Sadegh MAHMOODI, Teymooor GHANBARI [View]
[Download]

Abstract: In this paper a general improved wireless load sharing controller for a modular inverter system is proposed. Unlike conventional approaches, the proposed method is able to shares power accurately between N dissimilar paralleled inverters. Furthermore, it could remove high dependency on inverter output impedance and provide good output voltage regulation. Different simulation and experimental results are provided to validate the performance of the proposed method.

   A NEW MAINS VOLTAGE OBSERVER FOR PMSM DRIVES FED BY MATRIX CONVERTERS
By Andrea FORMENTINI, LILIANA DE LILLO, MARIO MARCHESONI, ANDREW TRENTIN, Patrick WHEELER, Pericle ZANCHETTA [View]
[Download]

Abstract: This paper presents a new Finite Control Set Model Predictive Control (FCS-MPC) algorithm with sensorless mains voltage detection, which has been applied to a Permanent Magnet Synchronous Motor (PMSM) driven by a Matrix Converter (MC). Unlike classical MC modulation methods, FCS-MPC allows direct control of the MC input currents. The mains voltage sensors elimination allows to increase the reliability of the system. The performance of the proposed work has been verified by simulation studies and experimental results.

   A Radial Basis Function Neural Networks Based Space-Vector PWM Controller for Voltage-Fed Inverter
By Yuxiang ZHAN, Yanfeng CHEN, Bo ZHANG, Jianzhuang CHEN [View]
[Download]

Abstract: In this paper, the basic principle of space-voltage vector PWM (SVPWM) is presented. Due to backpropagation neural networks (BP) based SVPWM controller have local optimization problem andlower training rate, a radial basis function neural networks (RBF) controller based SVPWM isproposed. Using Matlab/Simulink together with Neural Network Toolbox, we develop a computersimulation program for the RBF-SVPWM Inverter. The results indicate that the RBF-SVPWMInverter generates less current harmonic distortion than BP- SVPWM Inverter and the traditionalSVPWM Inverter.

   An Alternative Structure of the PMSM Drive Vector Control
By Valentin DZHANKHOTOV, Alexander MIKEROV, Lasse LAURILA, Juha PYRHÖNEN [View]
[Download]

Abstract: This paper considers a new system structure, which does not require current sensors for control and isoptimized for medium- and small-power drives with strict requirements on precision. The maindifference between traditional vector control and the proposed structure is a direct axis currentcompensator (DACC). DACC simplifies the control algorithms and cheapens the control hardware, inparticular, making phase current sensors unneeded. Experimental results showing similarity of thetraditional and proposed structures are presented. In conclusion, advantages and drawbacks of theproposed method are comprehensively analyzed.

   An Enhanced Modulator Concept for the Modular Multilevel Converter
By Markus SCHROEDER, Stefan HENNINGER, Johann JAEGER, Andreja RASIC, Hubert RUBENBAUER, Tobias LANG [View]
[Download]

Abstract: This paper deals with an enhanced modulator concept for the Modular Multilevel Converter. Based on an overview on existing concepts including module sorting algorithms and measurement results from a hardware-setup in laboratory, a new concept is developed. Measurement results of the implemented new algorithm for module selection and capacitor energy balancing in various operating points of the converter are presented and analyzed in detail. This elaboration is completed with a classification of the suggested modulator concept compared to established concepts.

   Control Concept and Stability Considerations of the Modular High Frequency Converter
By Anna MAYER, Christian ROLFF, Rainer MARQUARDT [View]
[Download]

Abstract: Excellent dynamic behavior and controllability even under fault conditions are main requirements of future electric drive systems. The Modular High Frequency Converter (MHF) fulfills these requirements and enables additional advantages especially low weight, low volume and redundant operation after faults. This paper presents control strategies and stability considerations for the new topology of the Modular High Frequency Converter. Simulations and first measurement results of the fully controlled laboratory prototype are shown.

   Control Scheme of Modular Multilevel Inverter for AC Drive Applications
By Xiaoxin WANG, Qiongxuan GE, Ming LEI, Yang YU, Yaohua LI [View]
[Download]

Abstract: By now the modular multilevel converter (MMC) is mainly applied to high frequency applications (50 or 60Hz) especially in the field of HVDC systems. This paper presents a control scheme for modular multilevel converter, which allows the converter to operate at continuous coverage in the 0Hz to 50Hz frequency band.

   Current Loop Dead Beat Control with the Digital PI-controller
By Alecksey ANUCHIN, Vladimir KOZACHENKO [View]
[Download]

Abstract: This paper shows the possibility of dead-beat control for a current loop with a traditional PI-controller. Two different ways of PI-controller parameter calculations are presented. The modeling shows that dead-beat behavior of the current controller is possible if the predictive feedback is used and its calculation algorithm is presented. Algorithm includes winding circuit inductance estimation, correction of ADC feedback measurement to take into account preamplifiers filter impact and ADC noise. All tests were performed on a DC-motor model but the results can be used for alternating current motors.

   Deadbeat Control of an AC-DC Converter
By Albert ISKHAKOV, Sergey SKOVPEN, Vladimir POSPELOV, Mutalib EMIRALIEV, Nikolai KOVALENKO [View]
[Download]

Abstract: A structure of an AC-DC converter control system based on a deadbeat controller that allows to obtain a finite duration transient in the small neighborhood of an equilibrium state is offered. The key feature of this deadbeat controller is that it enables to reduce a system matrix to the Frobenius form without transformation of variables as contrasted to the known variant of a deadbeat controller. A design procedure to obtain deadbeat controller parameters for one-phase controlled rectifier used for stabilizing a current in an active-inductive load is stated. Simulation of the converter transients during current reference step changes is given to demonstrate high efficiency of the proposed deadbeat controller.

   Digital control of IGBTs for module shutdown in input-series and output-parallel connected modular DC-DC converter
By Yeh TING, Kewei HUANG, Braham FERREIRA [View]
[Download]

Abstract: In an input-series and output-parallel (ISOP) connected modular DC-DC converter, the input voltagerange can be significantly increased by shutting down the respective modules. Additionally, theconverters efficiency at certain input voltage can be increased by utilising the most optimum numberof operating modules. The shutdown of non-essential modules is implemented with the availableIGBTs in the input bridge of the modules. Due to the large amount of energy stored in the input buscapacitors especially at high input voltages, the IGBTs have to be controlled to limit the initialdischarge current from the input capacitors. Digital control is hence employed here to accuratelycontrol the IGBTs in their active region during module shutdown to ensure operation within their safeoperation region. A complex programmable logic device (CPLD) is used here to generate the requiredgate voltage based on current and voltage feedback from the IGBTs. Upon completion of shutdown,the algorithm enables the IGBTs to fully turn on and operate in their saturation region to create a lowresistance current bypass path. The details of the digital control as well as its implementation arediscussed here. Results of the module shutdown and module reactivation with the implemented digitalcontrol are subsequently experimentally verified.

   Elimination of vector changes due to sector changes with DTC
By Georg TOLSTOY, Björn LARSSON, Oskar WALLMARK, Staffan NORRGA, Hans-Peter NEE [View]
[Download]

Abstract: In this paper it has been investigated if there is a possibility to reduce the switching frequency for atwo-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switchingcondition when a new sector is entered. It is believed that the DTC switching table can be improved byadding a non-switching condition when sector change occurs. This will reduce the number of switchingactions by up to 12 per electrical rotation without interfering with the electrical machine performance.

   Physical Insight into the Factors Affecting the Load-Transient Response of a Buck Converter
By Teuvo SUNTIO, Jyri KIVIMÄKI [View]
[Download]

Abstract: This paper investigates the physical issues affecting the load transient response both from the power-stage-component-selection and control-design point of views. A conventional buck converter under three different control schemes direct-duty-ratio control, peak-current control and peak-current-control with load-current-feedforward control is used as an example. The outcomes of the investigation are validated by simulations and experimental tests.

   Position-sensorless control of a submersible PMSM fed over a long cable and two transformers
By Torbjörn THIRINGER, Morten Thule HANSEN, Torbjørn STRØMSVIK, Harald Bjørn ULVESTAD [View]
[Download]

Abstract: This paper proposes the combination of two sensorless control algorithms for the secure start-up andthe efficient operation of a remotely-controlled PMSM. V/ f control is applied during the start-up of themotor and vector control is used for operation at higher speeds. The investigated system consists of along step-out configuration with a cable and two transformers between the PMSM and its VSD. Thesystem is tested with simulations and with experiments on a lab model. The results demonstrate thatV/ f control can safely start the PMSM. The effect of the inertia of the rotating assembly, the load torqueand the initial rotor position on the start-up performance of the system is investigated and the successfultransition from V/ f control to vector control is demonstrated.

   Precise Ripple Cancellation Technique for Power-Factor Pre-regulator Circuits
By Ka Hei LEUNG, Ka Hong LOO, Yuk Ming LAI [View]
[Download]

Abstract: Power-factor pre-regulators generally suffer from poor dynamic response due to the need to limit the propagation of output voltage ripple at double line frequency into the voltage control loop and to achieve a satisfactory power factor performance. Ripple cancellation methods have been proposed to eliminate the double-line-frequency signal from the sampled output voltage before it propagates into the voltage control loop. However, these methods generally employ idealized formulations that give rise to accurate ripple estimation over a limited range of operating conditions only. In this paper, a new ripple estimation/cancellation circuit that does not rely on such idealized formulations is proposed. It consists of an independent amplitude tuner circuit and a phase shifter circuit that can provide accurate ripple estimation over a wide range of operating conditions. The proposed circuit is analyzed in detail and verified theoretically by computer simulation. It is shown that ripple cancellation provides a way to decouple the pre-regulator's power factor from its controller's bandwidth and load condition, thus both fast dynamic response and constant near-unity power factor can be achieved.

   Switching Time Prediction for Digital Hysteresis Control for High Frequency Current in Grid Impedance Measurement Application
By Sandro GUENTER, Friedrich Wilhelm FUCHS [View]
[Download]

Abstract: The measurement of the grid impedance is important for lter and control design, for active lter func-tionality of grid connected inverters and also for distribution network operators. It supports knowledgeof the grid and design of decentralized energy generator power #64258;ow. Not only the impedance at fun-damental frequency but also the impedance at harmonic and interharmonic frequencies is of commoninterest. With an inverter injecting a current at an individual frequency onto the power system, the realfrequency dependent value of the grid impedance can be determined. A digital hysteresis current controlis a promising method to control a voltage source inverter (VSI) for high frequency current generationin grid impedance measurement application. Digital signal processing is state of the art, but the speed ofthe analog to digital conversion is limited. When using hysteresis current control the outcome of this isthat the current leaves the dened hysteresis band because of the time discrete sampling. In this papera method using switching time prediction to minimize this current overshoot is proposed and analyzed.Simulation and measurement results are presented that show the suitability of this method.

   Voltage Balancing Control of a Three-Phase Hybrid-Clamped Five-Level Inverter Based on Optimal Zero-Sequence Voltage Injection
By Zedong ZHENG, Xiaokun WU, Yongdong LI, Kui WANG [View]
[Download]

Abstract: As the society pursuing for a more efficient way of using energy, the technology of multilevel converter, which aims at the field of large-power high-voltage, has been widely studied. In this paper, a newly released single phase hybrid-clamped five-level inverter has been extended to three phases. The characteristics of this topology and the switching states have been analyzed. To solve the voltage balance problem of the DC-bus capacitors and flying capacitors, a control strategy based on optimal zero-sequence voltage injection has been proposed. The strategy selects the optimal switching combinations according to their influences on the voltages of capacitors. With the injection of zero-sequence voltage, we can extend the voltage balance region of this topology compared to the existing control method. The proposed control strategy has been verified in simulations and experiments. Furthermore, the control strategy is a universal strategy which can be applied into other multilevel converters.

EPE 2014 - DS1b: Standard and Advanced Control Techniques for Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2014 ECCE Europe - Conference > EPE 2014 - Topic 03: Measurement and Control > EPE 2014 - DS1b: Standard and Advanced Control Techniques for Power Converters
	[return to parent folder]

	A General Wireless Strategy for Load Sharing Among Dissimilar Paralleled Inverters By Ebrahim FARJAH, Sadegh MAHMOODI, Teymooor GHANBARI	[View] [Download]
Abstract: In this paper a general improved wireless load sharing controller for a modular inverter system is proposed. Unlike conventional approaches, the proposed method is able to shares power accurately between N dissimilar paralleled inverters. Furthermore, it could remove high dependency on inverter output impedance and provide good output voltage regulation. Different simulation and experimental results are provided to validate the performance of the proposed method.

	A NEW MAINS VOLTAGE OBSERVER FOR PMSM DRIVES FED BY MATRIX CONVERTERS By Andrea FORMENTINI, LILIANA DE LILLO, MARIO MARCHESONI, ANDREW TRENTIN, Patrick WHEELER, Pericle ZANCHETTA	[View] [Download]
Abstract: This paper presents a new Finite Control Set Model Predictive Control (FCS-MPC) algorithm with sensorless mains voltage detection, which has been applied to a Permanent Magnet Synchronous Motor (PMSM) driven by a Matrix Converter (MC). Unlike classical MC modulation methods, FCS-MPC allows direct control of the MC input currents. The mains voltage sensors elimination allows to increase the reliability of the system. The performance of the proposed work has been verified by simulation studies and experimental results.

	A Radial Basis Function Neural Networks Based Space-Vector PWM Controller for Voltage-Fed Inverter By Yuxiang ZHAN, Yanfeng CHEN, Bo ZHANG, Jianzhuang CHEN	[View] [Download]
Abstract: In this paper, the basic principle of space-voltage vector PWM (SVPWM) is presented. Due to backpropagation neural networks (BP) based SVPWM controller have local optimization problem andlower training rate, a radial basis function neural networks (RBF) controller based SVPWM isproposed. Using Matlab/Simulink together with Neural Network Toolbox, we develop a computersimulation program for the RBF-SVPWM Inverter. The results indicate that the RBF-SVPWMInverter generates less current harmonic distortion than BP- SVPWM Inverter and the traditionalSVPWM Inverter.

	An Alternative Structure of the PMSM Drive Vector Control By Valentin DZHANKHOTOV, Alexander MIKEROV, Lasse LAURILA, Juha PYRHÖNEN	[View] [Download]
Abstract: This paper considers a new system structure, which does not require current sensors for control and isoptimized for medium- and small-power drives with strict requirements on precision. The maindifference between traditional vector control and the proposed structure is a direct axis currentcompensator (DACC). DACC simplifies the control algorithms and cheapens the control hardware, inparticular, making phase current sensors unneeded. Experimental results showing similarity of thetraditional and proposed structures are presented. In conclusion, advantages and drawbacks of theproposed method are comprehensively analyzed.

	An Enhanced Modulator Concept for the Modular Multilevel Converter By Markus SCHROEDER, Stefan HENNINGER, Johann JAEGER, Andreja RASIC, Hubert RUBENBAUER, Tobias LANG	[View] [Download]
Abstract: This paper deals with an enhanced modulator concept for the Modular Multilevel Converter. Based on an overview on existing concepts including module sorting algorithms and measurement results from a hardware-setup in laboratory, a new concept is developed. Measurement results of the implemented new algorithm for module selection and capacitor energy balancing in various operating points of the converter are presented and analyzed in detail. This elaboration is completed with a classification of the suggested modulator concept compared to established concepts.

	Control Concept and Stability Considerations of the Modular High Frequency Converter By Anna MAYER, Christian ROLFF, Rainer MARQUARDT	[View] [Download]
Abstract: Excellent dynamic behavior and controllability even under fault conditions are main requirements of future electric drive systems. The Modular High Frequency Converter (MHF) fulfills these requirements and enables additional advantages especially low weight, low volume and redundant operation after faults. This paper presents control strategies and stability considerations for the new topology of the Modular High Frequency Converter. Simulations and first measurement results of the fully controlled laboratory prototype are shown.

	Control Scheme of Modular Multilevel Inverter for AC Drive Applications By Xiaoxin WANG, Qiongxuan GE, Ming LEI, Yang YU, Yaohua LI	[View] [Download]
Abstract: By now the modular multilevel converter (MMC) is mainly applied to high frequency applications (50 or 60Hz) especially in the field of HVDC systems. This paper presents a control scheme for modular multilevel converter, which allows the converter to operate at continuous coverage in the 0Hz to 50Hz frequency band.

	Current Loop Dead Beat Control with the Digital PI-controller By Alecksey ANUCHIN, Vladimir KOZACHENKO	[View] [Download]
Abstract: This paper shows the possibility of dead-beat control for a current loop with a traditional PI-controller. Two different ways of PI-controller parameter calculations are presented. The modeling shows that dead-beat behavior of the current controller is possible if the predictive feedback is used and its calculation algorithm is presented. Algorithm includes winding circuit inductance estimation, correction of ADC feedback measurement to take into account preamplifiers filter impact and ADC noise. All tests were performed on a DC-motor model but the results can be used for alternating current motors.

	Deadbeat Control of an AC-DC Converter By Albert ISKHAKOV, Sergey SKOVPEN, Vladimir POSPELOV, Mutalib EMIRALIEV, Nikolai KOVALENKO	[View] [Download]
Abstract: A structure of an AC-DC converter control system based on a deadbeat controller that allows to obtain a finite duration transient in the small neighborhood of an equilibrium state is offered. The key feature of this deadbeat controller is that it enables to reduce a system matrix to the Frobenius form without transformation of variables as contrasted to the known variant of a deadbeat controller. A design procedure to obtain deadbeat controller parameters for one-phase controlled rectifier used for stabilizing a current in an active-inductive load is stated. Simulation of the converter transients during current reference step changes is given to demonstrate high efficiency of the proposed deadbeat controller.

	Digital control of IGBTs for module shutdown in input-series and output-parallel connected modular DC-DC converter By Yeh TING, Kewei HUANG, Braham FERREIRA	[View] [Download]
Abstract: In an input-series and output-parallel (ISOP) connected modular DC-DC converter, the input voltagerange can be significantly increased by shutting down the respective modules. Additionally, theconverters efficiency at certain input voltage can be increased by utilising the most optimum numberof operating modules. The shutdown of non-essential modules is implemented with the availableIGBTs in the input bridge of the modules. Due to the large amount of energy stored in the input buscapacitors especially at high input voltages, the IGBTs have to be controlled to limit the initialdischarge current from the input capacitors. Digital control is hence employed here to accuratelycontrol the IGBTs in their active region during module shutdown to ensure operation within their safeoperation region. A complex programmable logic device (CPLD) is used here to generate the requiredgate voltage based on current and voltage feedback from the IGBTs. Upon completion of shutdown,the algorithm enables the IGBTs to fully turn on and operate in their saturation region to create a lowresistance current bypass path. The details of the digital control as well as its implementation arediscussed here. Results of the module shutdown and module reactivation with the implemented digitalcontrol are subsequently experimentally verified.

	Elimination of vector changes due to sector changes with DTC By Georg TOLSTOY, Björn LARSSON, Oskar WALLMARK, Staffan NORRGA, Hans-Peter NEE	[View] [Download]
Abstract: In this paper it has been investigated if there is a possibility to reduce the switching frequency for atwo-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switchingcondition when a new sector is entered. It is believed that the DTC switching table can be improved byadding a non-switching condition when sector change occurs. This will reduce the number of switchingactions by up to 12 per electrical rotation without interfering with the electrical machine performance.

	Physical Insight into the Factors Affecting the Load-Transient Response of a Buck Converter By Teuvo SUNTIO, Jyri KIVIMÄKI	[View] [Download]
Abstract: This paper investigates the physical issues affecting the load transient response both from the power-stage-component-selection and control-design point of views. A conventional buck converter under three different control schemes direct-duty-ratio control, peak-current control and peak-current-control with load-current-feedforward control is used as an example. The outcomes of the investigation are validated by simulations and experimental tests.

	Position-sensorless control of a submersible PMSM fed over a long cable and two transformers By Torbjörn THIRINGER, Morten Thule HANSEN, Torbjørn STRØMSVIK, Harald Bjørn ULVESTAD	[View] [Download]
Abstract: This paper proposes the combination of two sensorless control algorithms for the secure start-up andthe efficient operation of a remotely-controlled PMSM. V/ f control is applied during the start-up of themotor and vector control is used for operation at higher speeds. The investigated system consists of along step-out configuration with a cable and two transformers between the PMSM and its VSD. Thesystem is tested with simulations and with experiments on a lab model. The results demonstrate thatV/ f control can safely start the PMSM. The effect of the inertia of the rotating assembly, the load torqueand the initial rotor position on the start-up performance of the system is investigated and the successfultransition from V/ f control to vector control is demonstrated.

	Precise Ripple Cancellation Technique for Power-Factor Pre-regulator Circuits By Ka Hei LEUNG, Ka Hong LOO, Yuk Ming LAI	[View] [Download]
Abstract: Power-factor pre-regulators generally suffer from poor dynamic response due to the need to limit the propagation of output voltage ripple at double line frequency into the voltage control loop and to achieve a satisfactory power factor performance. Ripple cancellation methods have been proposed to eliminate the double-line-frequency signal from the sampled output voltage before it propagates into the voltage control loop. However, these methods generally employ idealized formulations that give rise to accurate ripple estimation over a limited range of operating conditions only. In this paper, a new ripple estimation/cancellation circuit that does not rely on such idealized formulations is proposed. It consists of an independent amplitude tuner circuit and a phase shifter circuit that can provide accurate ripple estimation over a wide range of operating conditions. The proposed circuit is analyzed in detail and verified theoretically by computer simulation. It is shown that ripple cancellation provides a way to decouple the pre-regulator's power factor from its controller's bandwidth and load condition, thus both fast dynamic response and constant near-unity power factor can be achieved.

	Switching Time Prediction for Digital Hysteresis Control for High Frequency Current in Grid Impedance Measurement Application By Sandro GUENTER, Friedrich Wilhelm FUCHS	[View] [Download]
Abstract: The measurement of the grid impedance is important for lter and control design, for active lter func-tionality of grid connected inverters and also for distribution network operators. It supports knowledgeof the grid and design of decentralized energy generator power #64258;ow. Not only the impedance at fun-damental frequency but also the impedance at harmonic and interharmonic frequencies is of commoninterest. With an inverter injecting a current at an individual frequency onto the power system, the realfrequency dependent value of the grid impedance can be determined. A digital hysteresis current controlis a promising method to control a voltage source inverter (VSI) for high frequency current generationin grid impedance measurement application. Digital signal processing is state of the art, but the speed ofthe analog to digital conversion is limited. When using hysteresis current control the outcome of this isthat the current leaves the dened hysteresis band because of the time discrete sampling. In this papera method using switching time prediction to minimize this current overshoot is proposed and analyzed.Simulation and measurement results are presented that show the suitability of this method.

	Voltage Balancing Control of a Three-Phase Hybrid-Clamped Five-Level Inverter Based on Optimal Zero-Sequence Voltage Injection By Zedong ZHENG, Xiaokun WU, Yongdong LI, Kui WANG	[View] [Download]
Abstract: As the society pursuing for a more efficient way of using energy, the technology of multilevel converter, which aims at the field of large-power high-voltage, has been widely studied. In this paper, a newly released single phase hybrid-clamped five-level inverter has been extended to three phases. The characteristics of this topology and the switching states have been analyzed. To solve the voltage balance problem of the DC-bus capacitors and flying capacitors, a control strategy based on optimal zero-sequence voltage injection has been proposed. The strategy selects the optimal switching combinations according to their influences on the voltages of capacitors. With the injection of zero-sequence voltage, we can extend the voltage balance region of this topology compared to the existing control method. The proposed control strategy has been verified in simulations and experiments. Furthermore, the control strategy is a universal strategy which can be applied into other multilevel converters.