Shunt Active Power Filter Based on Cross-Switched Multilevel Inverter

摘要

Shunt Active Power Filter (APF) is a shunt connected converter which can controlled in a way that the nonlinear load current harmonics on the grid side as well as the reactive power can be compensated. In this research, a shunt active power filter is proposed based on the cross-switched multilevel inverter (CSMLI). Owing to the inherent feature of capacitors voltages self-balancing capability in this multilevel inverter, the capacitors voltage balance is achieved. As the output voltage waveform is a multilevel waveform, the quality of the output waveforms is improved. The employed control system for the proposed APF includes the second-order generalized integrator phase-locked loop (SOGI-PLL) for synchronization with the grid and the proportional-resonant (PR) as the current controller. Using SOGI makes it possible for the APF to operate properly even if the grid voltage is extremely polluted by harmonics. Simulation results on a single-phase 5-level inverter based APF are presented to verify its performance in current harmonics mitigation and reactive power compensation. Also, the voltage balance among capacitors is obtained.