Modeling and Simulation of PMSG Based Stand-alone Wind Energy Conversion System

Abstract

The quest for higher living standard and rise of population force us to think about alternate energy sources as conventional energy sources have certain limitations. Therefore the focus has been shifted towards renewable sources of energy, as it is present in abundant amount and it will not create environmental pollution. Among the renewable sources of energy,wind energy is used as it is cost effective and available in all season. So in this context; PMSG based wind energy conversion system has increasingly drawn the interest of researcher. The model of wind energy conversion system (WECS) based on PMSG is presented. This model consists of wind turbine, PMSG, ac-dc rectifier, dc link and inverter. PMSG is used for variable speed operation and to capture maximum power from wind turbine during variable speed. Maximum power point tracking (MPPT) is done. The simulation of MPPT is done during step change in wind speed. The small capacity wind turbine will response to small change in wind speed and it will affect the output voltage. The output voltage is controlled by gearbox, but gearbox increases the weight and maintenance. In order to overcome these drawbacks direct driven PMSG is used for this purpose. It does not require any additional supply for excitation. The torque of the generator changes according to the speed and maximum power of wind turbine is found by MPPT control. For a small scale PMSG based wind turbine, MPPT control is done by using boost chopper. Then the dc voltage is converted to stable ac voltage by using inverter circuit.