New Converter Topologies for Two-Phase Wind Turbine PMSG Generation System

Abstract

Direct drive, grid-connected permanent magnet synchronous generator (PMSG) system is an important trend of development for wind power applications nowadays. Extracting as much power as possible from wind energy and feeding high quality electricity to grids are two main objectives of the PMSG generation systems, while obtaining a suitable dc-link voltage is the key to realize these objectives. The Authors have developed an innovative two-phase PMSG - converter system for direct-drive, variable-speed wind turbines. This paper mainly presents novel front-end rectifiers in the system. To increase the dc-link voltage at low wind speeds, one topology called "boost voltage" topology is presented through comprehensive research on various topologies suitable for two-phase input rectifiers. The presented topology can significantly improve the wind power extraction capability and the quality of electricity fed to a grid, especially valuable for the operation of generation system under low to medium wind speeds. In order to further improve the wind power extracting capability, two dual-IBGT modules are used to replace 2 of the 3 arms of the rectifier. Therefore, a topology named boost rectifier is presented. The boost rectifier not only increases the dc-link voltage, but also realizes the function of power factor adjustment of the two-phase PMSG. The two-phase wind turbine PMSG system employing the presented topologies was modeled and simulated using PSCAD platform, while test results further verified the presented topologies.