Z-Source/Quasi-Z-Source AC-DC Rectifiers

Active rectifiers are attractive as an interface for ac-dc conversion for use in electric vehicle charging, because of their high efficiency and bidirectional operation. This chapter discusses the voltage-fed Z-source and quasi-Z-source rectifier, which improve the voltage boosting capability of the traditional voltage source rectifier, are immune to short-circuit of the phase legs, and are able to conduct both inverter and converter modes bilaterally. When analyzing the dc side, the rectifier bridge is equivalent to a current source. From simulation results of phase voltages and currents, it can be seen that unity power factor is obtained through the control method, in both inverter and rectifier modes. The quasi-Z-source rectifier was further taken as an example to illustrate their steady-state operating principles, dynamic modeling, control scheme, and simulation results, providing the fundamentals for the future development of such rectifiers.