EPE Association: NORpie 2006 - Topic 07: Power Quality

NORpie 2006 - Topic 07: Power Quality
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2006 > NORpie 2006 - Topic 07: Power Quality

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   Control Method to Improve the Transient Performance of a Current Sensorless Active Power Filter
By M. Routimo; M. Salo; H. Tuusa [View]
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Abstract: The performance of a conventional shunt active filter is heavily dependent on accurate current sensing and a complicated control algorithm. This paper presents an improved control method for a voltage source active power filter that does not require any information on the currents to compensate the harmonics. The operating principles and space-vector control of the system are presented and analyzed. The control based on the steady state equations is found to cause dc components to supply currents. Thus the transient state performance is improved using a compensation method based on the dynamic model of the system. Finally, the current sensorless active filter is examined with simulations and the performance is confirmed with experiments in the laboratory.

   Effect on Power Quality of the High Power Electric Traction (Double Domain Computer Simulation vs. Site Measurements)
By A. Dán; P. Kiss [View]
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Abstract: The paper shows the present results of a long term research work. The authors are working on the modeling of penetration of harmonics caused by the railways. In a former paper [1] a detailed model of the traction system was discussed in frequency domain. However this paper presents the combination of frequency and time dependent model. This novel method, called double domain method is used to improve the accuracy of the frequency domain simulation. To calculate the sophisticated model of the electric locomotive as a non-linear load a time dependent model must be used. The traction supply system together with the equivalent supply network impedance could be calculated in frequency domain. An iteration algorithm is developed to converting the variables in every iteration step between the time and frequency domain.

   Improving Power Quality in Three-Phase Four-Wire Systems with a Current Source Active Power Filter
By S. Pettersson; Mika Salo; H. Tuusa [View]
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Abstract: Although three-phase three-wire shunt active power filters have been implemented using both voltage and current source technology, four-wire shunt active power filters have mainly been implemented as voltage source active power filters. This paper presents a study of a current source shunt four-wire active power filter topology. The main circuit of the studied topology consists of a four-leg current source PWM converter bridge with an LC-filter on the supply side. The control system is implemented discretely-timed in the synchronous reference frame in an open-loop manner using only a feedforward connection of the load currents. The control delay is compensated using a prediction based current reference generation method in the steady state and a computational control delay compensation method in the transient state of operation. The performance of the proposed system is tested through computer simulations.

   Improvement of the Compensation Performance of UPQC
By J. Turunen; M. Salo; H. Tuusa [View]
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Abstract: This paper deals with the improvement of the control system of a unified power quality conditioner in order to improve its compensation performance. The main circuit and the control system of the proposed unified power quality conditioner (UPQC) are first presented. After this, two methods applied to the control system of the UPQC in order to improve its compensation performance are discussed. These methods are control delay compensation and crosscoupling compensation. In the literature, these methods are applied to the control system of the parallel active power filter. However, in this paper these methods are applied to the control system of the UPQC. The functioning of the methods is validated using simulation whose results are presented in the end of this paper. Simulation results in stationary and dynamic operation are presented and discussed.

NORpie 2006 - Topic 07: Power Quality
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2006 > NORpie 2006 - Topic 07: Power Quality
	[return to parent folder]

	Control Method to Improve the Transient Performance of a Current Sensorless Active Power Filter By M. Routimo; M. Salo; H. Tuusa	[View] [Download]
Abstract: The performance of a conventional shunt active filter is heavily dependent on accurate current sensing and a complicated control algorithm. This paper presents an improved control method for a voltage source active power filter that does not require any information on the currents to compensate the harmonics. The operating principles and space-vector control of the system are presented and analyzed. The control based on the steady state equations is found to cause dc components to supply currents. Thus the transient state performance is improved using a compensation method based on the dynamic model of the system. Finally, the current sensorless active filter is examined with simulations and the performance is confirmed with experiments in the laboratory.

	Effect on Power Quality of the High Power Electric Traction (Double Domain Computer Simulation vs. Site Measurements) By A. Dán; P. Kiss	[View] [Download]
Abstract: The paper shows the present results of a long term research work. The authors are working on the modeling of penetration of harmonics caused by the railways. In a former paper [1] a detailed model of the traction system was discussed in frequency domain. However this paper presents the combination of frequency and time dependent model. This novel method, called double domain method is used to improve the accuracy of the frequency domain simulation. To calculate the sophisticated model of the electric locomotive as a non-linear load a time dependent model must be used. The traction supply system together with the equivalent supply network impedance could be calculated in frequency domain. An iteration algorithm is developed to converting the variables in every iteration step between the time and frequency domain.

	Improving Power Quality in Three-Phase Four-Wire Systems with a Current Source Active Power Filter By S. Pettersson; Mika Salo; H. Tuusa	[View] [Download]
Abstract: Although three-phase three-wire shunt active power filters have been implemented using both voltage and current source technology, four-wire shunt active power filters have mainly been implemented as voltage source active power filters. This paper presents a study of a current source shunt four-wire active power filter topology. The main circuit of the studied topology consists of a four-leg current source PWM converter bridge with an LC-filter on the supply side. The control system is implemented discretely-timed in the synchronous reference frame in an open-loop manner using only a feedforward connection of the load currents. The control delay is compensated using a prediction based current reference generation method in the steady state and a computational control delay compensation method in the transient state of operation. The performance of the proposed system is tested through computer simulations.

	Improvement of the Compensation Performance of UPQC By J. Turunen; M. Salo; H. Tuusa	[View] [Download]
Abstract: This paper deals with the improvement of the control system of a unified power quality conditioner in order to improve its compensation performance. The main circuit and the control system of the proposed unified power quality conditioner (UPQC) are first presented. After this, two methods applied to the control system of the UPQC in order to improve its compensation performance are discussed. These methods are control delay compensation and crosscoupling compensation. In the literature, these methods are applied to the control system of the parallel active power filter. However, in this paper these methods are applied to the control system of the UPQC. The functioning of the methods is validated using simulation whose results are presented in the end of this paper. Simulation results in stationary and dynamic operation are presented and discussed.