DC-Link Voltage Regulation of Bidirectional Quasi-Z-Source Inverter for Electric Vehicle Applications

In order to regulate the dc-link voltage and achieve the bidirectional power flow capability, a traction driving system with bidirectional quasi-Z-source inverter (BQ-ZSI) for electric vehicles (EV) is proposed in this paper. Based on analyzing the circuit structure and small signal model, oscillation of the dc-link voltage of BQ-ZSI could be caused when the disturbances on dc input voltage occur. By producing a dc-link voltage controller with a capacitor voltage feedback control in addition to dc input voltage and inductor current feed-forward compensation, the oscillation of the dc-link voltage and inductor current produces by the disturbance on dc input voltage can be suppressed. Simulation results show that EVs can be operated among startup, climbing, acceleration and regenerative braking modes with a stable dc-link voltage. The proposed control strategy can effectively stabilize the dc-link voltage of the BQ- ZSI traction driving system when the dc input voltage varies and the operation mode of EV changes.