A new current control strategy for active power filters using three PWM voltage source inverters

A new current control strategy for active power filters using multiple PWM voltage-source inverters is presented and analyzed. The proposed current control strategy operates each PWM voltage-source inverter with a different switching frequency generating specific current harmonic components of the load. Reactive power is compensated without sensing and computing the reactive component of the load current, thus simplifying the control circuit. Current harmonics are compensated in the time domain. The active power filter presented is implemented with three PWM voltage-source inverters connected to a self-controlled DC bus. The authors discuss the proposed scheme in terms of principles of operation, power and control system design, and the analysis under steady-state and transient operation conditions. Simulated results obtained for steady-state and transient operating conditions are presented and validated on a 20-kVA experimental unit