A Novel Combined System Using Cascaded Active Power Filter and Static Var Compensator for High-Power Applications

As a compromise between economy and good performance, this paper adopts the combined system using cascaded active power filter (APF) and static var compensator(SVC) to compensate reactive power and harmonic currents simultaneously for high-power applications. The SVC is constructed by fixed capacitor (FC) and thyristor controlled reactor (TCR), and the APF is constructed by a cascaded multi-level voltage source converter and its filter reactor. SVC acts as a classic reactive power compensator for load balancing and power factor correction, and APF is used to compensate the harmonic current. Firstly, the circuit topology and the principle of the combined system are introduced in detail. Then filtering characteristics using the novel control method are analyzed. Furthermore, the steady state and dynamic waveforms show that good performance and system stability of the combined system are achieved.