Quasi‐Z‐source matrix converters to be used in PMSG‐based WECS: Modeling, control, and comparison

摘要

In this paper, 2 quasi-Z-source matrix converters (qZSMCs) namely quasi-Z-source MC with discontinuous input current (qZSMC-I) and quasi-Z-source MC with continuous input current (qZSMC-II) are studied, and their dynamic characteristics are fully investigated. First, their small-signal models in space domain are obtained by state-space averaging method, providing an insight into their dynamic characteristics and their constraints. Their transfer functions are further calculated whereby they are analyzed to see how variations of passive elements and shoot-through duty ratio affect the locations of transfer functions' poles and zeros, and their transient responses. The results together with a frequency domain analysis based on Bode plot are then used to render an in-depth guide to choose proper passive elements for each Z-source MC. Further, they are compared with each other by means of simulation results while being used as grid interfaces of a permanent-magnet synchronous generator-wind energy conversion system. A control system is also designed for each Wind energy conversion system to enhance its low voltage ride-through capability.