Double PI Control of DC Link Voltage for Three-Phase Four-Wire Shunt Active Power Filter

DC link voltage control is the key technology of shunt APF. The magnitude of DC link voltage affects the power loss and compensation capability of APF. In a complex industrial environment, load fluctuations will cause grid voltage fluctuations at common coupling points, which will further affect the compensation capability of active power filters. This paper analyzed the DC link voltage of three-phase four-wire shunt APF. The combination of conventional PI control and fuzzy control is adopted to stabilize the DC link voltage. Finally, based on simulation analysis and experiments, the scheme is proved to be effective.