EPE Association: EPE 2011 - DS1e: Topic 16: Active Filtering and Other Advanced Grid Side Converter Control

EPE 2011 - DS1e: Topic 16: Active Filtering and Other Advanced Grid Side Converter Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 16: Power electronics in transmission and distribution > EPE 2011 - DS1e: Topic 16: Active Filtering and Other Advanced Grid Side Converter Control

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   A 4-Limb Flying Capacitor - Based Active Power Filter for Unbalanced Distribution Networks
By Michael WAITE, Li ZHANG [View]
[Download]

Abstract: A strategy is presented for the control of a 4-limb flying-capacitor multi-level inverter (FCMI) as anactive power filter for unbalanced load conditions. Improved reference tracking is achieved using amodified deadbeat controller, and a naturally-balanced 3DPWM technique enables sensor-lessflying-capacitor voltage control. Simulation results show the effectiveness of the proposed scheme.

   A new control method for eliminating the 2nd harmonic at the DC link of a shunt APF under an unbalanced and nonlinear load
By Pengpai DANG, Jürgen PETZOLDT [View]
[Download]

Abstract: Under an unbalanced load 2nd harmonic DC link and 3rd harmonic at AC input current of a shunt APF appear due to the fundamental negative frequency load current. These low order harmonics can cause a series of high order harmonics at both of AC and DC sides. In this paper a new control method is presented to eliminate the 2nd ripple of DC link voltage to alleviate the stress of the DC-link capacitor and thus to reduce the 3rd harmonic of line currents.

   A Novel AC-AC Shunt Active Power Filter without Large Energy Storage Elements
By Quanwei LIU, Yan DENG, Xiangning HE [View]
[Download]

Abstract: Shunt active power filters are widely adopted to compensate for harmonic current and poor power factor generated by nonlinear loads and VAR loads such as diode bridge rectifier, lighting, motor drives, etc. Inverter-type shunt active power filters are commonly used, which employing large electrolytic capacitors as energy storage elements in the DC side. This paper presents a novel three-phase three-wire AC-AC shunt active power filter without large energy storage elements to realize dynamic VAR and harmonic current compensation. No bulky electrolytic capacitors are needed and bridge-type IGBT modules could be utilized to realize the bi-directional switches, which ensure low cost and high reliability. A 15kVA experimental prototype is built to validate the VAR and harmonic current compensation capability of the proposed converter.

   A Predictive Dead-Beat PI Current Controller for Active Power Filters
By Zhongfu ZHOU, Chun WANG, Petar IGIC [View]
[Download]

Abstract: In this paper, a predictive dead-beat proportional-integral (PI) current control algorithm is studied for shunt active power filters (APFs). To investigate the effectiveness of the proposed control scheme a digital control based simulation model is built using commercially available VisSim software. Performance comparison with different control schemes are carried out. Excellent performance of active power filter has been achieved based on the proposed control strategy.

   A Three-Phase Hybrid Filter for Medium Voltage Applications Using an H-Bridge
By Ignacio CANDELA, Pedro RODRIGUEZ, Khairul NISAK, Kalle RAUMA, J. Ramón HERMOSO, Ion ETXEBERRIA [View]
[Download]

Abstract: This paper presents a new solution for filtering current harmonics in three-phase thee-wire medium voltage networks. The hybrid filter topology presented in this paper is characterized by the use of an H-Bridge instead of the usual thee-phase inverter. This H-bridge is directly connected in series with a passive filter tuned around sixth harmonic. This paper provides a theoretical explanation on voltage control of H-bridge in three-phase systems. The good performance of this new topology as well as the proposed controller will be evaluated by means of simulations.

   Commutation effect of Adjustable Speed Drives due to installation of Active Harmonic Filters
By Lucian ASIMINOAEI, Sergej KALASCHNIKOW, Steffan HANSEN, Frede BLAABJERG [View]
[Download]

Abstract: The success of designing an industrial installation with Active Filters depends on how precise the load profile of the application is known, because this determines the amount of harmonic currents to be compensated. However, once the Active Filter is added to the installation, the harmonic currents may increase due to changes in the commutation behavior of diode rectifier converters. The change of natural commutation determines higher harmonics currents of the diode rectifiers and therefore higher harmonic loading of the Active Filter in the installation. This paper presents a method to estimate the commutation behavior of Adjustable Speed Drives when their harmonic currents are compensated by a Shunt Active Filter. The method is formulated as an analytical computation algorithm verified by simulations. Further on the method is implemented in a Harmonic Calculation Toolbox which facilitates calculation and sizing industrial Active Filter applications together with Adjustable Speed Drives. Examples of using the developed toolbox are given in the paper, supported with practical measurements.

   FRT Capability of Direct Power Controlled Converters connected by an Actively Damped LCL-Filter for Wind Power Applications
By Jan REESE, Ralf LOHDE, Friedrich W. FUCHS [View]
[Download]

Abstract: A Direct Power Control method for grid connected voltage source converters in wind power applications is investigated and improved. A damping algorithm for the LCL-filter as well as a FRT concept is designed and applied. The proposed control method is analyzed in regard to the fault ride through behavior required by the grid codes and shows good performance. Steady-state and dynamic performance of this control are shown by simulation and measurement results.

   Power Quality Conditioner with Series-Parallel Compensation Applied to Single-Phase Systems
By Rodrigo BARRIVIERA, Sergio SILVA, Rodrigo MODESTO, Alessandro GOEDTEL, Maurício KASTER [View]
[Download]

Abstract: This work deals with compensation algorithm schemes used in single-phase Unified Power Quality Conditioner (UPQC), allowing harmonic suppression and sag/swell compensation of the input voltage. In addition, reactive power compensation and harmonic suppression of the input current are also carried out, resulting in an effective power factor correction. Two different operation modes are employed to control the UPQC using Synchronous Reference Frame (SRF) based controllers. In the first mode the series converter acts as a sinusoidal current source, while the parallel converter acts as a sinusoidal voltage source. In the second mode, the series converter acts as a non-sinusoidal voltage source, while the parallel converter acts as a non-sinusoidal current source. A comparative analysis of the two operation modes is made, in which the advantages and disadvantages of each are discussed. Validation results are presented to confirm the theoretical development and performance of the single-phase UPQC.

   Ramp Based Control of DVR to Mitigate Voltage Sags/Swells
By Sridhar KANNAIAN, Mahesh Kumar MISHRA [View]
[Download]

Abstract: The Dynamic Voltage Restorer (DVR) is a custom power device connected in series with the load, whichcan control the voltage applied to the load by injecting a voltage of arbitrary amplitude, phase andharmonic component into the line. The conventional hysteresis voltage controller of DVR is simpleto implement and has a fast dynamic response etc. However, it suffers from the demerit of variableswitching frequency, which may be prohibitively high, increasing the stress levels on the switches andalso switching losses. In this paper, a ramp based control of DVR is used to achieve a simple closedloop control and constant switching frequency. The method is also extended to a ramp controller withhysteresis to achieve a reduced constant value of the switching frequency. Detailed simulation has beencarried out using PSCAD software.

   Reduction of High Frequency zero sequence harmonics in parallel connected PV-inverters
By Marco MAURI, Maria Stefania CARMELI, Luisa FROSIO, Gabriele MARCHEGIANI, Alberto BEZZOLATO [View]
[Download]

Abstract: High power photovoltaic plants are usually constituted of the connection of different photovoltaic subfields, each of them with its interface transformer. Different solutions have been studied to improve the efficiency of the whole generation system. In particular transformerless configurations are the more attractive one from efficiency and costs point of view. This paper focuses on transformerless photovoltaic configurations characaterised by the parallel connection of interface inverters. The problem of zero sequence current due to both the parallel connection and to the presence of undesirable parasitic earth capacitances is considered and a solution, which consists on the synchronisation of PWM triangular carrier is proposed and theoretically analysed. The theoretical analysis has been validated through simulation and experimental results.

   Single-Phase Series Active Conditioner Active Power Flow in a Harmonic Free Electrical System during Sag and Swell Events
By Helder CARNEIRO, Bruno EXPOSTO, Henrique GONCALVES, Pinto GABRIEL, João Luiz AFONSO [View]
[Download]

Abstract: This paper presents a Single-Phase Active Conditioner, which primal function is regulate load voltage,thus protecting the most sensitive loads from sags, swells, flicker and voltage harmonics. It isconstituted by two back-to-back H-bridge converters. One regulates load voltage, the other DC-linkvoltage. This paper will focus essentially on the active power flow during sag and swell events, in aharmonic free Electrical System. It is shown that, ideally, during a sag or swell event, the active powerconsumed from the AC mains, is the same that is delivered to the load. It also shows how this is achieved, by analyzing the working principle of the Single-Phase Series Active Converter, and, particularly, the crucial action of the DC link capacitor. The control strategy of the proposed custompower device is also presented in a brief form, for contextualization with the operating principle forthe compensation of voltage variation events. Simulation results are presented, showing transient andsteady state waveforms of the Single-phase Series Active Conditioner with a purely resistive load. The controller of Series Active Conditioner was implemented on a TMS320F2812F from TexasInstruments. Experimental results are also presented, and for better understanding of the active powerflow in the Single-Phase Series Active Conditioner, the implemented electrical system has only a resistive load.

   Supporting Unbalanced Grids with Induction Machine Drives by Inverters without Intermittent Energy Storage
By Klaus KRISCHAN, Roland SEEBACHER, Annette MUETZE [View]
[Download]

Abstract: A method for supporting unbalanced grids by utilizing a drive system with induction machine and inverter with no or low intermittent energy storage is proposed. Even though the instantaneous power, that is drawn from the mains is oscillating, the torque and speed of the machine are maintained constant.A strategy for obtaining the time dependent reference values for the flux linkage and the torque building current of a rotor field oriented control of an induction machine is presented. Some necessary enhancements to the control algorithm are discussed. Simulation results show the feasibility of the proposed method and control schemes. Measurement results from a practical implementation are given. A discussion of additional losses inherent to the proposed method and control schemes concludes the paper.

   Test Platform of Smart Grids with Renewable Energy Systems and Plug-in Hybrid Electric Vehicles
By Yonghua CHENG [View]
[Download]

Abstract: The main goal of smart grids via ICT infrastructure is to limit the peak power with less required capacity of energy storages or to maximally supply power for the local loads from the renewable energy sources, if there is a certain percent of time shift-table power sources and loads. However, the response time of these sources and loads might be significant. Moreover, the impact of large scale integration of renewable energy sources and plug-in hybrid electric vehicles in smart grids cannot be ignored. In order to ensure the stability and reliability, power difference must be limited in the different time scales. In this paper, a test platform of smart grids with super capacitor based peak power unit and plug-in hybrid electric vehicles is presented. And the enhanced strategies of power management are evaluated in islanding mode as well as in grid connected mode. The evaluation results prove that seamless grid connection/disconnection can be realised by using the presented control principles in this paper.

   Transformerless Series Active Power Filter to Compensate Voltage Disturbances
By Gabriel PINTO, João AFONSO, Carlos COUTO, Helder CARNEIRO, Bruno EXPOSTO [View]
[Download]

Abstract: This paper presents a transformerless topology of series active power filter with capability toprotect sensitive loads against harmonics, sags, swells and unbalances of the power systemvoltages. The proposed topology is constituted by three isolated H-bridge with a voltage sourceat the DC side. The series active power filter has been studied with the help of PSIM (PowerSimulation software) and simulation results are presented. A laboratory prototype is underdevelopment and experimental results are shown.

   Two Control Strategies Comparison of a Three Phase Shunt Active Power Filter for Power Quality Improvement with experimental validation
By Jean-Paul GAUBERT [View]
[Download]

Abstract: This paper presents the comparative evaluation of the performance of two control techniques to determine the reference current for a three phase shunt active power filter (APF) in order to improve the power quality and compensate reactive power required by nonlinear load. The first one is based on the use of classic PI controller and the second one is based on instantaneous power theory (p-q theory). Both control techniques are based on time domain, simulated with Matlab/Simulink and validated with an experimental test bench developed in the LAII laboratory, University of Poitiers. Various simulation and experimental results are presented under steady state and transient conditions with a comparison between the two control techniques.

EPE 2011 - DS1e: Topic 16: Active Filtering and Other Advanced Grid Side Converter Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 16: Power electronics in transmission and distribution > EPE 2011 - DS1e: Topic 16: Active Filtering and Other Advanced Grid Side Converter Control
	[return to parent folder]

	A 4-Limb Flying Capacitor - Based Active Power Filter for Unbalanced Distribution Networks By Michael WAITE, Li ZHANG	[View] [Download]
Abstract: A strategy is presented for the control of a 4-limb flying-capacitor multi-level inverter (FCMI) as anactive power filter for unbalanced load conditions. Improved reference tracking is achieved using amodified deadbeat controller, and a naturally-balanced 3DPWM technique enables sensor-lessflying-capacitor voltage control. Simulation results show the effectiveness of the proposed scheme.

	A new control method for eliminating the 2nd harmonic at the DC link of a shunt APF under an unbalanced and nonlinear load By Pengpai DANG, Jürgen PETZOLDT	[View] [Download]
Abstract: Under an unbalanced load 2nd harmonic DC link and 3rd harmonic at AC input current of a shunt APF appear due to the fundamental negative frequency load current. These low order harmonics can cause a series of high order harmonics at both of AC and DC sides. In this paper a new control method is presented to eliminate the 2nd ripple of DC link voltage to alleviate the stress of the DC-link capacitor and thus to reduce the 3rd harmonic of line currents.

	A Novel AC-AC Shunt Active Power Filter without Large Energy Storage Elements By Quanwei LIU, Yan DENG, Xiangning HE	[View] [Download]
Abstract: Shunt active power filters are widely adopted to compensate for harmonic current and poor power factor generated by nonlinear loads and VAR loads such as diode bridge rectifier, lighting, motor drives, etc. Inverter-type shunt active power filters are commonly used, which employing large electrolytic capacitors as energy storage elements in the DC side. This paper presents a novel three-phase three-wire AC-AC shunt active power filter without large energy storage elements to realize dynamic VAR and harmonic current compensation. No bulky electrolytic capacitors are needed and bridge-type IGBT modules could be utilized to realize the bi-directional switches, which ensure low cost and high reliability. A 15kVA experimental prototype is built to validate the VAR and harmonic current compensation capability of the proposed converter.

	A Predictive Dead-Beat PI Current Controller for Active Power Filters By Zhongfu ZHOU, Chun WANG, Petar IGIC	[View] [Download]
Abstract: In this paper, a predictive dead-beat proportional-integral (PI) current control algorithm is studied for shunt active power filters (APFs). To investigate the effectiveness of the proposed control scheme a digital control based simulation model is built using commercially available VisSim software. Performance comparison with different control schemes are carried out. Excellent performance of active power filter has been achieved based on the proposed control strategy.

	A Three-Phase Hybrid Filter for Medium Voltage Applications Using an H-Bridge By Ignacio CANDELA, Pedro RODRIGUEZ, Khairul NISAK, Kalle RAUMA, J. Ramón HERMOSO, Ion ETXEBERRIA	[View] [Download]
Abstract: This paper presents a new solution for filtering current harmonics in three-phase thee-wire medium voltage networks. The hybrid filter topology presented in this paper is characterized by the use of an H-Bridge instead of the usual thee-phase inverter. This H-bridge is directly connected in series with a passive filter tuned around sixth harmonic. This paper provides a theoretical explanation on voltage control of H-bridge in three-phase systems. The good performance of this new topology as well as the proposed controller will be evaluated by means of simulations.

	Commutation effect of Adjustable Speed Drives due to installation of Active Harmonic Filters By Lucian ASIMINOAEI, Sergej KALASCHNIKOW, Steffan HANSEN, Frede BLAABJERG	[View] [Download]
Abstract: The success of designing an industrial installation with Active Filters depends on how precise the load profile of the application is known, because this determines the amount of harmonic currents to be compensated. However, once the Active Filter is added to the installation, the harmonic currents may increase due to changes in the commutation behavior of diode rectifier converters. The change of natural commutation determines higher harmonics currents of the diode rectifiers and therefore higher harmonic loading of the Active Filter in the installation. This paper presents a method to estimate the commutation behavior of Adjustable Speed Drives when their harmonic currents are compensated by a Shunt Active Filter. The method is formulated as an analytical computation algorithm verified by simulations. Further on the method is implemented in a Harmonic Calculation Toolbox which facilitates calculation and sizing industrial Active Filter applications together with Adjustable Speed Drives. Examples of using the developed toolbox are given in the paper, supported with practical measurements.

	FRT Capability of Direct Power Controlled Converters connected by an Actively Damped LCL-Filter for Wind Power Applications By Jan REESE, Ralf LOHDE, Friedrich W. FUCHS	[View] [Download]
Abstract: A Direct Power Control method for grid connected voltage source converters in wind power applications is investigated and improved. A damping algorithm for the LCL-filter as well as a FRT concept is designed and applied. The proposed control method is analyzed in regard to the fault ride through behavior required by the grid codes and shows good performance. Steady-state and dynamic performance of this control are shown by simulation and measurement results.

	Power Quality Conditioner with Series-Parallel Compensation Applied to Single-Phase Systems By Rodrigo BARRIVIERA, Sergio SILVA, Rodrigo MODESTO, Alessandro GOEDTEL, Maurício KASTER	[View] [Download]
Abstract: This work deals with compensation algorithm schemes used in single-phase Unified Power Quality Conditioner (UPQC), allowing harmonic suppression and sag/swell compensation of the input voltage. In addition, reactive power compensation and harmonic suppression of the input current are also carried out, resulting in an effective power factor correction. Two different operation modes are employed to control the UPQC using Synchronous Reference Frame (SRF) based controllers. In the first mode the series converter acts as a sinusoidal current source, while the parallel converter acts as a sinusoidal voltage source. In the second mode, the series converter acts as a non-sinusoidal voltage source, while the parallel converter acts as a non-sinusoidal current source. A comparative analysis of the two operation modes is made, in which the advantages and disadvantages of each are discussed. Validation results are presented to confirm the theoretical development and performance of the single-phase UPQC.

	Ramp Based Control of DVR to Mitigate Voltage Sags/Swells By Sridhar KANNAIAN, Mahesh Kumar MISHRA	[View] [Download]
Abstract: The Dynamic Voltage Restorer (DVR) is a custom power device connected in series with the load, whichcan control the voltage applied to the load by injecting a voltage of arbitrary amplitude, phase andharmonic component into the line. The conventional hysteresis voltage controller of DVR is simpleto implement and has a fast dynamic response etc. However, it suffers from the demerit of variableswitching frequency, which may be prohibitively high, increasing the stress levels on the switches andalso switching losses. In this paper, a ramp based control of DVR is used to achieve a simple closedloop control and constant switching frequency. The method is also extended to a ramp controller withhysteresis to achieve a reduced constant value of the switching frequency. Detailed simulation has beencarried out using PSCAD software.

	Reduction of High Frequency zero sequence harmonics in parallel connected PV-inverters By Marco MAURI, Maria Stefania CARMELI, Luisa FROSIO, Gabriele MARCHEGIANI, Alberto BEZZOLATO	[View] [Download]
Abstract: High power photovoltaic plants are usually constituted of the connection of different photovoltaic subfields, each of them with its interface transformer. Different solutions have been studied to improve the efficiency of the whole generation system. In particular transformerless configurations are the more attractive one from efficiency and costs point of view. This paper focuses on transformerless photovoltaic configurations characaterised by the parallel connection of interface inverters. The problem of zero sequence current due to both the parallel connection and to the presence of undesirable parasitic earth capacitances is considered and a solution, which consists on the synchronisation of PWM triangular carrier is proposed and theoretically analysed. The theoretical analysis has been validated through simulation and experimental results.

	Single-Phase Series Active Conditioner Active Power Flow in a Harmonic Free Electrical System during Sag and Swell Events By Helder CARNEIRO, Bruno EXPOSTO, Henrique GONCALVES, Pinto GABRIEL, João Luiz AFONSO	[View] [Download]
Abstract: This paper presents a Single-Phase Active Conditioner, which primal function is regulate load voltage,thus protecting the most sensitive loads from sags, swells, flicker and voltage harmonics. It isconstituted by two back-to-back H-bridge converters. One regulates load voltage, the other DC-linkvoltage. This paper will focus essentially on the active power flow during sag and swell events, in aharmonic free Electrical System. It is shown that, ideally, during a sag or swell event, the active powerconsumed from the AC mains, is the same that is delivered to the load. It also shows how this is achieved, by analyzing the working principle of the Single-Phase Series Active Converter, and, particularly, the crucial action of the DC link capacitor. The control strategy of the proposed custompower device is also presented in a brief form, for contextualization with the operating principle forthe compensation of voltage variation events. Simulation results are presented, showing transient andsteady state waveforms of the Single-phase Series Active Conditioner with a purely resistive load. The controller of Series Active Conditioner was implemented on a TMS320F2812F from TexasInstruments. Experimental results are also presented, and for better understanding of the active powerflow in the Single-Phase Series Active Conditioner, the implemented electrical system has only a resistive load.

	Supporting Unbalanced Grids with Induction Machine Drives by Inverters without Intermittent Energy Storage By Klaus KRISCHAN, Roland SEEBACHER, Annette MUETZE	[View] [Download]
Abstract: A method for supporting unbalanced grids by utilizing a drive system with induction machine and inverter with no or low intermittent energy storage is proposed. Even though the instantaneous power, that is drawn from the mains is oscillating, the torque and speed of the machine are maintained constant.A strategy for obtaining the time dependent reference values for the flux linkage and the torque building current of a rotor field oriented control of an induction machine is presented. Some necessary enhancements to the control algorithm are discussed. Simulation results show the feasibility of the proposed method and control schemes. Measurement results from a practical implementation are given. A discussion of additional losses inherent to the proposed method and control schemes concludes the paper.

	Test Platform of Smart Grids with Renewable Energy Systems and Plug-in Hybrid Electric Vehicles By Yonghua CHENG	[View] [Download]
Abstract: The main goal of smart grids via ICT infrastructure is to limit the peak power with less required capacity of energy storages or to maximally supply power for the local loads from the renewable energy sources, if there is a certain percent of time shift-table power sources and loads. However, the response time of these sources and loads might be significant. Moreover, the impact of large scale integration of renewable energy sources and plug-in hybrid electric vehicles in smart grids cannot be ignored. In order to ensure the stability and reliability, power difference must be limited in the different time scales. In this paper, a test platform of smart grids with super capacitor based peak power unit and plug-in hybrid electric vehicles is presented. And the enhanced strategies of power management are evaluated in islanding mode as well as in grid connected mode. The evaluation results prove that seamless grid connection/disconnection can be realised by using the presented control principles in this paper.

	Transformerless Series Active Power Filter to Compensate Voltage Disturbances By Gabriel PINTO, João AFONSO, Carlos COUTO, Helder CARNEIRO, Bruno EXPOSTO	[View] [Download]
Abstract: This paper presents a transformerless topology of series active power filter with capability toprotect sensitive loads against harmonics, sags, swells and unbalances of the power systemvoltages. The proposed topology is constituted by three isolated H-bridge with a voltage sourceat the DC side. The series active power filter has been studied with the help of PSIM (PowerSimulation software) and simulation results are presented. A laboratory prototype is underdevelopment and experimental results are shown.

	Two Control Strategies Comparison of a Three Phase Shunt Active Power Filter for Power Quality Improvement with experimental validation By Jean-Paul GAUBERT	[View] [Download]
Abstract: This paper presents the comparative evaluation of the performance of two control techniques to determine the reference current for a three phase shunt active power filter (APF) in order to improve the power quality and compensate reactive power required by nonlinear load. The first one is based on the use of classic PI controller and the second one is based on instantaneous power theory (p-q theory). Both control techniques are based on time domain, simulated with Matlab/Simulink and validated with an experimental test bench developed in the LAII laboratory, University of Poitiers. Various simulation and experimental results are presented under steady state and transient conditions with a comparison between the two control techniques.