Inverse control of three-phase four-leg active power filter

Aiming at the problems that traditional PI control of DC capacitor voltage has Udc slow dynamic response, the period averaging dynamic model of APF including Vdc is established based on KVL. In order to have a good linearization control effect, the inverse control strategies is presented for three-phase four-leg Active Power Filter, and Aiming at the problem that the APF´s dynamic model is a multi -variable, nonlinear and strong coupling system, the diagonal-matrix decoupling method is adopted in this paper and the coupling system is decoupled into three indepent first-order linear subsystem: reactive current iq,zero sequence current i0 and DC capacitor voltage Vdc. The simulation results show that a rapid transient response can be obtained under the inverse control method.