Small-signal modeling of quasi-Z-source rectifier applying ZSVM3 in DCM switching operation

The three-phase quasi-Z-source rectifier (QZSR) can achieve soft switching without any auxiliary circuit applying modified ZSVM3. While the QZSR operates with discontinuous current mode (DCM), and the output voltage is unstable because of right half plane (RHP) zero. To address this problem, the circuit averaging method is used to analyse the steady-state model. The factors that affect the output voltage are presented. The small signal model and transfer functions are proposed. In addition, the RHP zero of QZSR is analysed and the control method is proposed to ensure the stability of system. The simulation and experiment results indicate that the small-signal model is consistent with theoretical analysis, and the output voltage remains the given value with the designed controller.