Digital Signal Processor Based Fuzzy Voltage and Frequency Regulator for Self-excited Induction Generator

This article presents digital design and implementation of a digital signal processor based fuzzy logic load controller to regulate the voltage and frequency of a three-phase self-excited induction generator through an equal time ratio control AC chopper controllable load that is suitable for a stand-alone power mode employing an unregulated turbine such as micro-hydro power generation. The self-excited induction generator can be used to generate constant voltage and frequency if the load is maintained constant at its terminals. Under such operation, the self-excited induction generator requires constant capacitance for excitation. For this purpose, a suitable control scheme is to be developed such that the load on the self-excited induction generator remains constant despite the change in the consumer load. The proposed fuzzy logic based load controller gives non-linear control with fast response and virtually no overshoot. The equal time ratio control AC chopper load controller regulates the dump load as a linear load with minimum harmonics and excellent dynamic response. The self-excited induction generator with such a control scheme is cost effective and provides quality power supply with minimum harmonics. A prototype self-excited induction generator-load controller system with a TMS320F2812 digital signal processor (Texas Instruments, USA) has been developed, and its transient behavior is investigated at different operating conditions such as application and removal of static (resistive and reactive) and dynamic loads.