Selection of suitable Topology and Switching Technique of ZSI for wind power application

A comparative study of three topologies of recently developed voltage-fed z-source inverter (ZSI) such as simple ZSI, quasi-ZSI and trans-QZSI is presented in this paper. Different control techniques, proposed earlier for simple ZSI such as simple boost control, maximum boost control and constant boost control, have been applied here for all type of ZSI topologies. The detailed comparative evaluation of all topologies under different control techniques is done in wind power applications. For the common boost factor and modulation index, the output voltage of all ZSIs with same dc power supply and load are evaluated. The operating principles are analysed and the boost factor, voltage gain, duty ratio and voltage stress across the switches are derived. The relationships among them are compared even under variable circuit parameters and switch frequency which suggests trans-QZSI with maximum constant boost control switching technique as the most suitable combination for the wind power application.