Variable speed wind turbine using the squirrel cage induction generator with reduced converter power rating for stand-alone energy systems

Abstract

This paper presents a new configuration for a wind energy conversion system (WECS) with variable speed, using a squirrel cage induction generator (SCIG) for stand-alone energy system applications. The Proposed configuration utilizes converters with reduced power rating, operates with MPPT to maximum wind energy extraction, uses battery bank for energy storage and can operate with non-linear and unbalanced loads. Energy storage characteristic is desirable for wind energy conversion systems isolated from the mains since an energy interruption does not stop of the entire system. Also, the power rating of the converters is reduced compared to the generator and load power rating due to the low power requirements of the power converters to SCIG excitation control and to supply the load. It is presented also the whole proposed WECS and the system operation modes according the turbine speed. It is presented also the whole proposed system and the system operation modes according the turbine speed. The simulation of the proposed WECS is performed in conjunction with the dynamic wind turbine model of 1 kW and the results confirm the effectiveness to supply unbalanced and non-linear loads, the converters power rating reduction and operation with variable turbine speed. Simulation results show the effectiveness of the system to supply unbalanced and non-linear stand alone loads.