Variable speed wind energy conversion system using PMSG & Z-Source inverter

Abstract

This project presents the simulation of Variable speed WECs using PMSG and Z-Source Inverter. Permanent-magnet synchronous generators (PMSGs) are used by these technologies due to special characteristics of PMSGs such as low weight and volume, high performance, and the elimination of the gearbox. In this project a new variable-speed WECS with a PMSG and Z-source inverter is proposed. The permanent magnet synchronous generator is controlled to obtain maximum power from the incident wind with maximum efficiency under different load conditions. Characteristics of Z-source inverter are used for maximum power tracking control and delivering power to the grid, simultaneously. Extracting maximum power from wind and feeding the grid with high-quality electricity are two main objectives for WECSs. To realize these objectives, the ac-dc-ac converter is one of the best topology for WECSs. The Z-source inverters have been reported recently as a competitive alternative to existing inverter topologies with many inherent advantages such as voltage boost. This inverter facilitates voltage boost capability with the turning ON of both switches in the same inverter phase leg. In this proposed topology, boost converter is omitted without any change in the objectives of the WECs. Reliability of the system is greatly improved, because the short circuit across any phase leg of inverter is allowed. Also, in this configuration, inverter output power distortion is reduced, since there is no need to phase leg dead time. This project introduces Z-source inverter and describes operation of rectifier feeding the Z source inverter. Then power delivery and MPPT control of system are explained.