A Novel Ripple Self-injection APF for Quasi-Z- source Inverter

Quasi-Z source inverters are composed of Quasi-Z source network and H-bridge inverter, and doublefrequency (2ω) ripple inevitably exists on the DC side of the H-bridge inverter in single-phase Quasi-Z source inverter. In this paper, a self-injection APF control strategy is proposed for Quasi-Z source network 2ω ripple problem. The state space averaging method is used to study the transmission mechanism of 2ω energy. Combined with the small signal model of Quasi-Z source network, it is found that the duty cycle disturbance can affect the energy distribution of Quasi- Z source network. Superimposing compensation signal on the duty cycle of the through circuit can inject 2ω energy into the H-bridge inverter by using the Quasi-Z source network without changing the circuit topology and restrain the input power fluctuation of the Quasi-Z source network. The simulation results verify the effectiveness of the proposed control strategy, which reduces the input current ripple amplitude of Quasi-Z source by 99.4%. The response speed of the proposed control strategy is simulated and analyzed with feedback control method.