Power, Voltage and Frequency Optimization of a PMSG Based WECS

Abstract

The global need for cheap environment friendly energy generation has grown over recent decade due to the depletion of fossil sources. Considering the needs of future generation, renewable sources are the main focus of research work in recent decades. Compared to other sources wind energy is found to be one of the preferred alternative for many power corporation. But because of the random and erratic nature of wind some mean of control strategy must be developed in order to extract as much power as possible. Therefore in this thesis a Hill-climb search (HCS) algorithm is implemented which can efficiently track the optimum power point at fast varying wind condition and also demonstrates battery connected operation for an independent wind energy conversion system (WECS). The hill-climb search algorithm is independent of the wind turbine power-speed characteristics and the wind speed hence it is a sensor less approach. Here the wind speed is changed in step wise manner and the maximum power is tracked using the HCS algorithm in SIMULINK based environment. Thus a variable speed operation is obtained from the permanent magnet synchronous generator (PMSG). Due to variable speed operation and variation of load (due to fault and overload condition) leads to huge oscillation and variation in the grid frequency and voltage waveform. Hence a voltage-frequency (VF) controller is designed to bring down the change in voltage and frequency into permissible limit. The VF controller is operated by a voltage source converter (VSC) and hybrid battery storage system. The VF controller regulates the active and reactive power supplied by battery and the generator and controls voltage and frequency fluctuation. In order to verify the proper working of the VF controller different load disturbances are introduced to the WECS and the voltage and frequency of the three-phase three-wire connection system are monitored regularly in a MATLAB based SIMULINK environment.