EPE Association: EPE 2001 - Topic 05b: Converter Control, Current / Voltage Control

EPE 2001 - Topic 05b: Converter Control, Current / Voltage Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 05: MODULATION STRATEGIES AND SPECIFIC CONTROL METHODS FOR STATIC CONVERTERS > EPE 2001 - Topic 05b: Converter Control, Current / Voltage Control

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   A New Sliding Mode Control Impletation
By O. López; L. García de Vicuña; M. Castilla; J. Matas [View]
[Download]

Abstract: A new sliding mode control implementation is presented in this paper. The proposed solution operates at constant switching frequency without using a ramp signal. Furthermore, the circuit complexity and the error produced by the chattering of the surface are reduced with regards the conventional approaches.

   A Novel Adaptive Hysteresis Constant Frequency Current Control
By P. Ninkovic [View]
[Download]

Abstract: This paper presents a novel adaptive-hysteresis predetermined constant frequency current-mode control for PWM DC/DC power converters. Theoretical examination is performed and one simple and easy-to-apply control low is derived. It is concluded that very fast and accurate response is maintained, while predetermined constant frequency steady-state operation is achieved. Moreover, the control low attains very small frequency variations during transients. Experimental 2KW buck converter is built to verify the theory. Some steady-state and transient tests are performed with results, which are consistent with the theory.

   A Voltage Source Active Rectifier with Controllable Power Factor and..
By Z. Chen; M. McCormick; N. Brown; L. Haydock [View]
[Download]

Abstract: The paper presents the study of an active rectifier based on a voltage source converter. The system characteristics are studied. The operational region and the factors affecting system efficiency are presented and discussed. The control variables, the power angle and the modulation ratio of the PWM power electronic converter, and their effects are investigated. The control strategies developed enable the voltage source active rectifier to perform power control at a desired power factor with minimized power loss while ac harmonics are reduced by using PWM switching. Simulation and experimental results show good agreement. The results from this study can be used to design active rectifier systems and to develop the associated control systems.

   Control method for multi-leg voltage-source inverters
By P. Delarue; A. Bouscayrol; E. Semail; B. François [View]
[Download]

Abstract: In this paper, a general and simple control method is proposed for any multi-leg voltage-source inverters. This strategy is based on a specific coding technique of the switching patterns. It is validated on an original 5-leg inverter, which supplies two independent induction machines. Applications to 3-leg and 4-leg structures are also presented. Finally a comparison with a standard Pulse Width Modulation points out its characteristics.

   Current control of utility-connected Inverters using repetitive feedback
By S. Abu-Sharkh; M.A. Abu-Sara; Z.F. Hussien [View]
[Download]

Abstract: The paper presents the simulation and experimental results of a repetitive feedback current control technique incorporated in hysteresis current controller for three-phase voltage-source inverter (VSI) to be connected between a DC source and the utility network through a LC filter. The results show that repetitive feedback control improves the THD of the output current of the inverter by compensating for the distortion that is caused by utility harmonics.

   Current Controlled Line Converter Using Direct Torque Control Method
By Antti Tarkiainen [View]
[Download]

Abstract: THIS PAPER HAS BEEN WITHDRAWED !

   Digital Current Controller with a very simple null-vector strategy
By E. Aldabas; J. L. Romeral; A. Arias; M. R. Chekkouri [View]
[Download]

Abstract: In this paper a new digital current regulator for three phase loads is proposed. It uses polar coordinates instead a-b co-ordinates in order to obtain a circular area for the current error trajectories. Moreover, the voltage vector applied to the load is accurately selected in order to minimise the switching frequency. The robustness against both external perturbations and changes in the reference values has been corroborated. The results of a comparative study illustrate the performance of the proposed controller compared with other known controllers, showing a good behaviour not only in steady state but also in transients.

   Fast Signal Conditioning in Single Phase Systems
By B. Burger; A. Engler [View]
[Download]

Abstract: Due to the increasing number of inverters in renewable supply systems and a lot of UPS-applications the control of single phase systems is becoming more important. Hence a new control strategy for single phase inverters has been derived which allows both precise control and fast signal conditioning. The vector control with PI-controllers, which is well known from three phase systems, allows the precise and fast control of inverters. In order to have the same advantages for single phase systems the vector control has been converted into a new topology, which works without the park transformation. Therefore the new algorithm does not require much computing power and can be utilised also in small inverters. Furthermore this algorithm provides a fictitious imaginary time function which allows the complex calculation of sinusoidal functions. This makes it possible to determine the instantaneous values of the modulus and the active and reactive power in single phase systems. The developed and tested algorithms even do not require to detect the zero-crossing of voltage and current. The combination of a precise control and the instantaneous availability of the single phase quantities make active filtering easy and allow e. g. the parallel operation of voltage source inverters without additional communication. The last feature is of great importance for the expandability of renewable supply systems and for UPS-systems. Almost all of the introduced applications have been tested successfully during the development of a battery inverter for renewable supply systems.

   Fixed frequency control laws for multi-cell chopper
By M. Fadel; T. Meynard [View]
[Download]

Abstract: In this paper, the authors present two fixed frequency control laws for the multicell chopper. The first is based on the partial linearizing feedback method associated with a linear control in series. The second is a fixed frequency control law involving a sliding mode approach. A broad part of this work is devoted to the characterisation of these two control laws in steady state and in transient state for a three-cell chopper.

   Frequency Domain Analysis of Space Vector Modulated Four-switch
By J. Klima [View]
[Download]

Abstract: The paper presents harmonic analysis of the space vector PWM waveform of the four-switch voltage source inverter feeding an induction motor drive.The analysis is based on a novel decomposition technique and on the Laplace transform of the voltage space vectors.As the phase voltages are in principle asymmetrical,first the asymmetrical space vector sequence is expressed in symmetrical form.It is shown that the asymmetrical space vector sequence can be expressed with two symmetrical sequences.First sequence has vectors that are mutually shifted by 600 as in conventional inverter,and second sequence has vectors shifted by 1800 and amplitudes are one half of the first sequence.Then the Laplace transform of the symmetrical space vector sequence is expressed.Using the relation between the Laplace transform of the periodic waveform and Fourier coefficients we can find the coefficients of the Fourier series.From the analytical relations we can derive harmonic spectra for different space vector modulation technique.

   Improved Four-Quadrant Converter Control for A.C. Traction Drive
By A. Dolcini; G. Superti-Furga [View]
[Download]

Abstract: This paper deals with a new current-based modulation method for four-quadrant converters in a.c. traction drives. The method uses standard constant frequency Sine PWM hardware in unconventional way, achieving the high dynamics typical of current hysteresis methods and improving line current waveform in transients. Comparison with standard Sine PWM control is reported.

   Influence of Dead Time Effects of PWM-VSI on Current Control
By P. Weichbold; T. von Raumer [View]
[Download]

Abstract: Non-ideal behaviour of the inverter, generally known as “dead time effect”, causes a voltage error in the inverter output voltage. This paper investigates the influence of this voltage error on current control used for field oriented controlled AC machines. The magnitude of pulsations of the q-axis current, responsible for the torque ripple of a drive system is analysed for both permanent magnet synchronous machine and induction machine. A feed-forward scheme to compensate the voltage error is proposed. Experimental results are presented in order to confirm the theoretical considerations and the effectiveness of the proposed compensation scheme.

   New optimal Methods for PWM inverter Deadtime Compensation
By L. Ben-Brahim [View]
[Download]

Abstract: To prevent the phase shortage of inverter arms, a time delay is inserted between the switches of the same arm. This lag-time causes serious distortions of the output voltage of the inverter. The lag-time is well know as dead-time effect. Conventional dead-time compensation methods based on current reference polarity, are widely used to improve the output current waveforms. The improved waveforms however still suffer from the zero current crossing phenomenon. This paper analysis the origins of waveform distortions arround the zero current crossing in PWM (Pulse Witdth Modulated) inverters. The conventional compensation methods as well as a three proposed methods to reduce the distortions in the PWM inverters output waveforms caused by dead-time and the zero crossing problem are highlighted. Theoretical analysis as well as simulation results to verify the proposed methods are described in this paper.

   Performance Analysis of PWM Rectifier with Active Filtering Function
By T. Kataoka; D. Nakajima; S. Nishikata [View]
[Download]

Abstract: The PWM rectifier investigated in this paper operates as a rectifier to supply DC power to its own load and at the same time, operates as an active power filter to supply to the AC line a compensating current to eliminate or reduce the harmonic current produced by a nonlinear load connected to the same AC line. Simulation analysis of this PWM rectifier is carried out in detail. Introducing a modulation ratio of PWM, the limit of harmonic compensation by the PWM rectifier is analyzed for two types of nonlinear loads. It is then shown that the total harmonic distortion of AC supply current after harmonic compensation is improved greatly compared to that before harmonic compensation. The influence of the active filtering operation of the PWM rectifier on the ripple factor of its DC output voltage is also clarified. Experimental results are included to confirm the validity of the simulation analysis.

   Pole-placement control of Voltage Source Rectifiers
By J. Doval-Gandoy; A. Iglesias; C. Peñalver [View]
[Download]

Abstract: This paper presents the analysis of the PWM boost rectifier when the pole assignment control method is used in order to improve the dynamic response of the rectifier, by using a reduced size dc-link capacitor. An experimental setup was performed with a 1.5kW boost rectifier, where the control algorithm was implemented by using a DSP.

   Predictive Middle Point Modulation: A new modulation method for A.F.
By M. A. Perales; J. M. Carrasco; J. A. Sánchez; L. Terrón; L.G. Franquelo. [View]
[Download]

Abstract: When designing an Active filter, using a current-controlled voltage source inverter, there are two main tasks : to generate an appropiate reference, for nulling harmonic current and reactive power, ant, on the other side, to generate a switching pattern that permits to follow the reference as close as it can be done. Predictive Middle Point Modulation (PMPM) is a novel modulation technique, specially suited for Active Filters. This method is derived from predictive Dead-Beat controller, improving its dynamic response and current error. Simulation results confirm the validity of the proposed method. Experimental results will be provided in the final paper.

   Simple Digital Control of Converters using Building Blocks
By M. Ossmann [View]
[Download]

Abstract: Digital control of converters usually needs a fast PWM generator and fast DSP processing. It is shown that using the direct digital synthesis (DDS) principle it is possible to generate a high resolution PWM-like control with much less processing power and low clock rates. This is achived by dithering on a coarse scale with low computational e®ort. If the Sigma-Delta principle is used as concept for analog to digital conversion it is possible to built complete controllers that are mainly based on digital circuitry. We show how to control converters with simple, cheap and low-power digital circuitry with the °exibility of software. Results from implementations are shown. As example a single-active-switch two-output converter has been built where both outputs are regulated using a 8 bit microcontroller.

   Simplified Control Of A Boost Power-Factor Pre-Regulator
By O. López; L. García de Vicuña; M. Castilla [View]
[Download]

Abstract: This paper describes the sliding mode control design of a Boost high-power-factor AC/DC pre-regulator. The proposed controller operates in continuous conduction mode and avoids the use of an analogue multiplier and sensing the line voltage. Therefore, it is an interesting solution when high efficiency and simple control circuit are required.

   Transformerless Parallel Three-Phase PWM Buck Rectifiers
By Zhihong Ye; Dushan Boroyevich [View]
[Download]

Abstract: This paper develops an average model of transformerless parallel three-phase PWM buck rectifiers. The model is based on a generic switching cell averaging that allows the model to preserve commonmode components. The common-mode components are critical in the analysis of circulating current in the parallel system, while they are usually neglected in a single converter model. Due to the transformerless structure, a zero-sequence circulating current may occur. The paper proposes a novel zero-sequence control so that the circulating current can be minimized. Simulation results with both average and switching models are provided.

   Variable Operating Point Robust Control Strategy For Boost Converters
By P. Sanchis Gúrpide; O. Alonso Sádaba; L. Marroyo Palomo [View]
[Download]

Abstract: This paper proposes a new robust and accurate control strategy for the Boost converter based on the compensation of non-linearities and external perturbations of the Boost continuos-time averaged model. This control strategy minimises the sensitivity to input voltage and output current variations, and achieves stable zero error tracking independently of the operating point.

EPE 2001 - Topic 05b: Converter Control, Current / Voltage Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 05: MODULATION STRATEGIES AND SPECIFIC CONTROL METHODS FOR STATIC CONVERTERS > EPE 2001 - Topic 05b: Converter Control, Current / Voltage Control
	[return to parent folder]

	A New Sliding Mode Control Impletation By O. López; L. García de Vicuña; M. Castilla; J. Matas	[View] [Download]
Abstract: A new sliding mode control implementation is presented in this paper. The proposed solution operates at constant switching frequency without using a ramp signal. Furthermore, the circuit complexity and the error produced by the chattering of the surface are reduced with regards the conventional approaches.

	A Novel Adaptive Hysteresis Constant Frequency Current Control By P. Ninkovic	[View] [Download]
Abstract: This paper presents a novel adaptive-hysteresis predetermined constant frequency current-mode control for PWM DC/DC power converters. Theoretical examination is performed and one simple and easy-to-apply control low is derived. It is concluded that very fast and accurate response is maintained, while predetermined constant frequency steady-state operation is achieved. Moreover, the control low attains very small frequency variations during transients. Experimental 2KW buck converter is built to verify the theory. Some steady-state and transient tests are performed with results, which are consistent with the theory.

	A Voltage Source Active Rectifier with Controllable Power Factor and.. By Z. Chen; M. McCormick; N. Brown; L. Haydock	[View] [Download]
Abstract: The paper presents the study of an active rectifier based on a voltage source converter. The system characteristics are studied. The operational region and the factors affecting system efficiency are presented and discussed. The control variables, the power angle and the modulation ratio of the PWM power electronic converter, and their effects are investigated. The control strategies developed enable the voltage source active rectifier to perform power control at a desired power factor with minimized power loss while ac harmonics are reduced by using PWM switching. Simulation and experimental results show good agreement. The results from this study can be used to design active rectifier systems and to develop the associated control systems.

	Control method for multi-leg voltage-source inverters By P. Delarue; A. Bouscayrol; E. Semail; B. François	[View] [Download]
Abstract: In this paper, a general and simple control method is proposed for any multi-leg voltage-source inverters. This strategy is based on a specific coding technique of the switching patterns. It is validated on an original 5-leg inverter, which supplies two independent induction machines. Applications to 3-leg and 4-leg structures are also presented. Finally a comparison with a standard Pulse Width Modulation points out its characteristics.

	Current control of utility-connected Inverters using repetitive feedback By S. Abu-Sharkh; M.A. Abu-Sara; Z.F. Hussien	[View] [Download]
Abstract: The paper presents the simulation and experimental results of a repetitive feedback current control technique incorporated in hysteresis current controller for three-phase voltage-source inverter (VSI) to be connected between a DC source and the utility network through a LC filter. The results show that repetitive feedback control improves the THD of the output current of the inverter by compensating for the distortion that is caused by utility harmonics.

	Current Controlled Line Converter Using Direct Torque Control Method By Antti Tarkiainen	[View] [Download]
Abstract: THIS PAPER HAS BEEN WITHDRAWED !

	Digital Current Controller with a very simple null-vector strategy By E. Aldabas; J. L. Romeral; A. Arias; M. R. Chekkouri	[View] [Download]
Abstract: In this paper a new digital current regulator for three phase loads is proposed. It uses polar coordinates instead a-b co-ordinates in order to obtain a circular area for the current error trajectories. Moreover, the voltage vector applied to the load is accurately selected in order to minimise the switching frequency. The robustness against both external perturbations and changes in the reference values has been corroborated. The results of a comparative study illustrate the performance of the proposed controller compared with other known controllers, showing a good behaviour not only in steady state but also in transients.

	Fast Signal Conditioning in Single Phase Systems By B. Burger; A. Engler	[View] [Download]
Abstract: Due to the increasing number of inverters in renewable supply systems and a lot of UPS-applications the control of single phase systems is becoming more important. Hence a new control strategy for single phase inverters has been derived which allows both precise control and fast signal conditioning. The vector control with PI-controllers, which is well known from three phase systems, allows the precise and fast control of inverters. In order to have the same advantages for single phase systems the vector control has been converted into a new topology, which works without the park transformation. Therefore the new algorithm does not require much computing power and can be utilised also in small inverters. Furthermore this algorithm provides a fictitious imaginary time function which allows the complex calculation of sinusoidal functions. This makes it possible to determine the instantaneous values of the modulus and the active and reactive power in single phase systems. The developed and tested algorithms even do not require to detect the zero-crossing of voltage and current. The combination of a precise control and the instantaneous availability of the single phase quantities make active filtering easy and allow e. g. the parallel operation of voltage source inverters without additional communication. The last feature is of great importance for the expandability of renewable supply systems and for UPS-systems. Almost all of the introduced applications have been tested successfully during the development of a battery inverter for renewable supply systems.

	Fixed frequency control laws for multi-cell chopper By M. Fadel; T. Meynard	[View] [Download]
Abstract: In this paper, the authors present two fixed frequency control laws for the multicell chopper. The first is based on the partial linearizing feedback method associated with a linear control in series. The second is a fixed frequency control law involving a sliding mode approach. A broad part of this work is devoted to the characterisation of these two control laws in steady state and in transient state for a three-cell chopper.

	Frequency Domain Analysis of Space Vector Modulated Four-switch By J. Klima	[View] [Download]
Abstract: The paper presents harmonic analysis of the space vector PWM waveform of the four-switch voltage source inverter feeding an induction motor drive.The analysis is based on a novel decomposition technique and on the Laplace transform of the voltage space vectors.As the phase voltages are in principle asymmetrical,first the asymmetrical space vector sequence is expressed in symmetrical form.It is shown that the asymmetrical space vector sequence can be expressed with two symmetrical sequences.First sequence has vectors that are mutually shifted by 600 as in conventional inverter,and second sequence has vectors shifted by 1800 and amplitudes are one half of the first sequence.Then the Laplace transform of the symmetrical space vector sequence is expressed.Using the relation between the Laplace transform of the periodic waveform and Fourier coefficients we can find the coefficients of the Fourier series.From the analytical relations we can derive harmonic spectra for different space vector modulation technique.

	Improved Four-Quadrant Converter Control for A.C. Traction Drive By A. Dolcini; G. Superti-Furga	[View] [Download]
Abstract: This paper deals with a new current-based modulation method for four-quadrant converters in a.c. traction drives. The method uses standard constant frequency Sine PWM hardware in unconventional way, achieving the high dynamics typical of current hysteresis methods and improving line current waveform in transients. Comparison with standard Sine PWM control is reported.

	Influence of Dead Time Effects of PWM-VSI on Current Control By P. Weichbold; T. von Raumer	[View] [Download]
Abstract: Non-ideal behaviour of the inverter, generally known as “dead time effect”, causes a voltage error in the inverter output voltage. This paper investigates the influence of this voltage error on current control used for field oriented controlled AC machines. The magnitude of pulsations of the q-axis current, responsible for the torque ripple of a drive system is analysed for both permanent magnet synchronous machine and induction machine. A feed-forward scheme to compensate the voltage error is proposed. Experimental results are presented in order to confirm the theoretical considerations and the effectiveness of the proposed compensation scheme.

	New optimal Methods for PWM inverter Deadtime Compensation By L. Ben-Brahim	[View] [Download]
Abstract: To prevent the phase shortage of inverter arms, a time delay is inserted between the switches of the same arm. This lag-time causes serious distortions of the output voltage of the inverter. The lag-time is well know as dead-time effect. Conventional dead-time compensation methods based on current reference polarity, are widely used to improve the output current waveforms. The improved waveforms however still suffer from the zero current crossing phenomenon. This paper analysis the origins of waveform distortions arround the zero current crossing in PWM (Pulse Witdth Modulated) inverters. The conventional compensation methods as well as a three proposed methods to reduce the distortions in the PWM inverters output waveforms caused by dead-time and the zero crossing problem are highlighted. Theoretical analysis as well as simulation results to verify the proposed methods are described in this paper.

	Performance Analysis of PWM Rectifier with Active Filtering Function By T. Kataoka; D. Nakajima; S. Nishikata	[View] [Download]
Abstract: The PWM rectifier investigated in this paper operates as a rectifier to supply DC power to its own load and at the same time, operates as an active power filter to supply to the AC line a compensating current to eliminate or reduce the harmonic current produced by a nonlinear load connected to the same AC line. Simulation analysis of this PWM rectifier is carried out in detail. Introducing a modulation ratio of PWM, the limit of harmonic compensation by the PWM rectifier is analyzed for two types of nonlinear loads. It is then shown that the total harmonic distortion of AC supply current after harmonic compensation is improved greatly compared to that before harmonic compensation. The influence of the active filtering operation of the PWM rectifier on the ripple factor of its DC output voltage is also clarified. Experimental results are included to confirm the validity of the simulation analysis.

	Pole-placement control of Voltage Source Rectifiers By J. Doval-Gandoy; A. Iglesias; C. Peñalver	[View] [Download]
Abstract: This paper presents the analysis of the PWM boost rectifier when the pole assignment control method is used in order to improve the dynamic response of the rectifier, by using a reduced size dc-link capacitor. An experimental setup was performed with a 1.5kW boost rectifier, where the control algorithm was implemented by using a DSP.

	Predictive Middle Point Modulation: A new modulation method for A.F. By M. A. Perales; J. M. Carrasco; J. A. Sánchez; L. Terrón; L.G. Franquelo.	[View] [Download]
Abstract: When designing an Active filter, using a current-controlled voltage source inverter, there are two main tasks : to generate an appropiate reference, for nulling harmonic current and reactive power, ant, on the other side, to generate a switching pattern that permits to follow the reference as close as it can be done. Predictive Middle Point Modulation (PMPM) is a novel modulation technique, specially suited for Active Filters. This method is derived from predictive Dead-Beat controller, improving its dynamic response and current error. Simulation results confirm the validity of the proposed method. Experimental results will be provided in the final paper.

	Simple Digital Control of Converters using Building Blocks By M. Ossmann	[View] [Download]
Abstract: Digital control of converters usually needs a fast PWM generator and fast DSP processing. It is shown that using the direct digital synthesis (DDS) principle it is possible to generate a high resolution PWM-like control with much less processing power and low clock rates. This is achived by dithering on a coarse scale with low computational e®ort. If the Sigma-Delta principle is used as concept for analog to digital conversion it is possible to built complete controllers that are mainly based on digital circuitry. We show how to control converters with simple, cheap and low-power digital circuitry with the °exibility of software. Results from implementations are shown. As example a single-active-switch two-output converter has been built where both outputs are regulated using a 8 bit microcontroller.

	Simplified Control Of A Boost Power-Factor Pre-Regulator By O. López; L. García de Vicuña; M. Castilla	[View] [Download]
Abstract: This paper describes the sliding mode control design of a Boost high-power-factor AC/DC pre-regulator. The proposed controller operates in continuous conduction mode and avoids the use of an analogue multiplier and sensing the line voltage. Therefore, it is an interesting solution when high efficiency and simple control circuit are required.

	Transformerless Parallel Three-Phase PWM Buck Rectifiers By Zhihong Ye; Dushan Boroyevich	[View] [Download]
Abstract: This paper develops an average model of transformerless parallel three-phase PWM buck rectifiers. The model is based on a generic switching cell averaging that allows the model to preserve commonmode components. The common-mode components are critical in the analysis of circulating current in the parallel system, while they are usually neglected in a single converter model. Due to the transformerless structure, a zero-sequence circulating current may occur. The paper proposes a novel zero-sequence control so that the circulating current can be minimized. Simulation results with both average and switching models are provided.

	Variable Operating Point Robust Control Strategy For Boost Converters By P. Sanchis Gúrpide; O. Alonso Sádaba; L. Marroyo Palomo	[View] [Download]
Abstract: This paper proposes a new robust and accurate control strategy for the Boost converter based on the compensation of non-linearities and external perturbations of the Boost continuos-time averaged model. This control strategy minimises the sensitivity to input voltage and output current variations, and achieves stable zero error tracking independently of the operating point.