Capacitor Excited Asynchronous Generator for an Isolated Wind Energy Conversion System

This paper deals with the control of voltage and frequency of an isolated wind energy conversion system (WECS) based on capacitor excited asynchronous generator and feeding 3-phase 4-wire loads. The proposed controller consists of an IGBT (Insulated Gate Bipolar Junction Transistor) based 4-leg voltage source converter (VSC) and a battery at DC link. Three legs of the converter are connected to each phase of the generator while fourth leg along-with neutral terminal of the capacitor creates the neutral terminal for the load. The proposed controller is having bidirectional flow capability of active and reactive powers by which it controls the system voltage and frequency with variation of consumer loads and the speed of the wind. The complete electromechanical system is modeled and simulated in MATLAB using Simulink and PSB (Power System Blockset) toolboxes. The simulated results are presented to demonstrate the capability of the proposed controller as a voltage and frequency regulator, harmonic eliminator, load balancer, and a neutral current compensator for different electrical (varying consumer loads) and mechanical (varying wind speed) dynamic conditions in an isolated wind energy conversion system.