Steady state investigation of self excited 3 phase induction generator with novel leading VAR controller and mitigation of harmonics using active power filter

Abstract

Self Excited Induction Generator (SEIG) is identified as isolated power source, whose terminal voltage and frequency are controlled by varying speed, excitation capacitance or load impedance. Since load changes from time to time, the output parameters mostly are controlled by either speed or by varying excitation capacitance. To reduce the complexity in analysis, the speed of a prime-mover driving the induction generator is kept constant. For proper voltage built-up suitable value of excitation capacitance is necessary. This paper presents a method for calculating the minimum excitation capacitance using the equivalent circuit approach for analyzing the steady state operation of SEIG. Change in load impedance forces alteration in the value of excitation capacitance which is difficult to be implemented. A novel leading VAR controller (LVARC) consisting of uncontrolled converter, inverter and a series LCR resonance circuit, is introduced in between the load and source to take care of reactive power disparity thereby feeding the reactive power to the inductive loads and absorbing reactive power for capacitive loads. A closed loop operation of SEIG was developed using Shunt Active Power Filter (SAF) is used for harmonic elimination. MATLAB based simulation and experimental results are presented and compared for VAR controller operated with linear loads. Simulation study is made for Non-Linear loads with respect to SAF's. The simulation results show the effectiveness of Voltage built-up and harmonic reduction in Wind based Power Generation.