Voltage and Frequency Controller for Isolated Asynchronous Generators Feeding 3-Phase 4-Wire Loads

This paper deals with the voltage and frequency controller (VFC) for isolated asynchronous generator feeding 3-phase 4-wire loads for constant power applications such as pico hydro uncontrolled turbines. An AC capacitor bank is used to self excite and to meet the reactive power requirement of the asynchronous generator which is also known as self excited induction generator (SEIG). The proposed VFC is realized using a IGBT(Insulated gate bipolar junction transistor) based current controlled 4-leg voltage source converter (CC-VSC) and a high frequency DC chopper at its DC bus, which keeps the generated voltage and frequency constant despite changes in consumer loads. The complete system is modeled in MATLAB along with Simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of asynchronous generator system with VF controller for feeding 3-phase 4-wire loads.