A new approach to control by model of a voltage source GTO active power filter

Abstract

Harmonics generated by high power conventional AC/DC converters have become a serious problem for the AC mains as they can only be removed by using bulky passive filters. However, the remarkable progress made by power electronic devices in recent years makes it possible to concieve the self-adaptable harmonic suppressor called active power filter. In this paper we described a new approach of PWM control based on a modelisation of the active power filter decoupling reactor. The system under consideration is composed of a voltage source active power filter and a SCR rectifier bridge supplying an inductive load. The rectifier generates harmonic currents. The active power filter should detect and compensate them in order to approach the sinewave current in the mains. The harmonic current reference is calculated according to the method based on the calculation of the instantaneous power described by Akagi, Nabae and Atoh (1986). The GTOs are controlled by using the space vector method. Each GTO will switch one time per sampling period of 670 μs. This control has a good aptitude to minimize undesirable harmonic currents. In order to take into account of the delay time corresponding to the calculation time of the microprocessor a prediction of the current references is used. The whole system described above is studied in this paper. The modeling and numerical simulation using the specified open loop control are considered. The reliability of the system with respect to the variation of the system parameters is investigated.