Control Techniques for Active Power Filters

With the widespread use of harmonic-generating devices, the control of harmonic currents to maintain a high level of power quality is becoming increasingly important. An effective way for harmonic suppression is the harmonic compensation by using active power filter. This paper presents a comprehensive survey of active power filter (APF) control strategies put forward recently. It is aimed at providing a broad perspective on the status of APF control methods to researchers and application engineers dealing with harmonic suppression issues. Many control techniques have been designed, developed, and realized for active filters in recent years. We classify all control methods into two main groups. The first group is reference parameter detection method. This can be done in either the time or frequency domain. The second group is derivation methods of the switching functions for active filters. In this paper, we mainly discuss the second group and its application. The paper also investigates some possibilities of new approach to control active power filters.