Dynamic Modelling and Control of PMSG based Stand-alone Wind Energy Conversion System

Abstract

This paper explains a control strategy for variable speed wind turbine coupled to a permanent magnet synchronous generator (PMSG) in stand-alone mode. The control structure for a variable speed wind turbine is explained with a maximum power extraction. The wind generating system consists of variable speed wind turbine (VSWT) with three types of wind speed data (i) Step wind speed (ii) Staircase wind speed and (iii) random wind speed, Permanent magnet synchronous generator, uncontrolled rectifier, voltage source inverter and Bidirectional DC-DC converter along with a Battery storage system has been presented. The control strategy is so adapted to supply the load with a constant voltage and frequency under load change and wind speed change. The control strategy involves control of the bi-directional DC-DC converter of a battery system in order to maintain the constant DC-link voltage due to the variation in wind speed to the constant DC-link voltage. The control strategy used for Inverter control consists of a DC-link control, voltage and current control which is used to control the load voltage and frequency under load variation. The wind energy system is modelled in MATLAB/ SIMULINK.