MATLAB simulation for Adjustable Speed Drive system for single phase induction motor using ZSI

This paper presents a simulation based technique in MATLAB for speed control of single phase induction motor using Impedance Source Inverter (ZSI). Adopting different control strategies, the same power circuit used for ZSI can be operated for dc-to-ac, ac-to-dc,ac-to-ac and dc-to-dc power conversions. ZSI consists of a unique impedance network to couple the converter main circuit to the power source. By reducing the voltage stress across the capacitors in the impedance network an effective and energy efficient speed control solution for induction motor can be achieved. Proposed work presents a scheme which has been implemented by employing a PID controller for providing a solution to reduce the voltage stress experienced by the capacitors present in ZSI. PID controller does it by constantly tuning the reference signal used to derive discrete PWM(pulse width modulation) signals for operating power switches in ZSI. PID controller gets the error signal from the measure of actual speed and reference speed. Inclusion of PID controller in control circuit of ZSI also mitigates stability and overshoots problems and hence expected to have a better speed regulation of induction motor driven through ZSI.