A rule-based fuzzy logic controller for a PWM inverter in a stand alone wind energy conversion scheme

The authors present a rule-based fuzzy logic controller (FLC) for controlling the output power of a pulse width modulated (PWM) inverter used in a stand-alone wind energy-conversion scheme (SAWECS). The self-excited induction generator used in SAWECS has the inherent problem of fluctuations in the magnitude and frequency of its terminal voltage with changes in wind velocity and load. To overcome this drawback the variable magnitude, variable frequency voltage at the generator terminals is rectified, and the DC power is transferred to the load through a PWM inverter. The objective is to track and extract maximum power to the local isolated load. This is achieved by using the FLC, which regulates the modulation index of the PWM inverter based on the input signals: the power error and its rate of change. The proposed FLC is simulated, and the results are experimentally verified on a scaled-down laboratory prototype of the SAWECS