Stability Analysis and Controller Design of Hybrid Compensation System with Parallel Active Power Filter and Parallel Capacitors

A hybrid compensation system with parallel active power filter and parallel capacitors is proposed in this paper, where parallel active power filter is used to cancel the current distortion and the capacitors are used to improved power factor. Firstly, stability of this hybrid compensation system is analyzed. With traditional control method, hybrid system is stable when the capacitor current is not included in the detected load current, but when the capacitor current is included in the detected load current system stability and performance of harmonic elimination is incompatible in this system. Then, a control method in which both the supply voltage and load current are detected to control the output current of parallel active power filter is proposed. The proposed control method makes the hybrid system work effectively when the capacitor current is included in the detected load current and it can be easily implemented in practices. Finally, simulations and experiments results are presented to demonstrate the conclusions.