A three-phase active power filter operating with fixed switchingfrequency for reactive power and current harmonic compensation

The performance and dynamic characteristics of a three-phase active power filter operating with fixed switching frequency is presented and analyzed in this paper. The proposed scheme employs a PWM voltage-source inverter and has two important characteristics. First, it operates with fixed switching frequency, and second, it can compensate the reactive power and the current harmonic components of nonlinear loads. Reactive power compensation is achieved without sensing and computing the reactive component of the load current, thus simplifying the control system. Current harmonic compensation is done in time domain. The principles of operation of the proposed active power filter along with the design criteria of the power and control circuit components are discussed in detail. Finally, experimental results obtained from a 5 kVA prototype confirm the feasibility and the features of the proposed system