Abstract: In this paper we present, harmonic analysis of single phase inverter based on unipolar pwm and bipolar pwm techniques. Simulation results of both the methods are also highlighted. In order to find the Total Harmonic Distortion (THD), FFT is used using mat lab/simulation software. It is found that performance of unipolar switching technique is better than bipolar switching technique in comparison of THD. It is observed that minimum value of THD of unipolar switching technique is 5.28 % and Bipolar switching technique is 11.03 % in case of amplitude modulation. Also in the case of frequency modulation we get 5.52% and 7.72% respectively.

Keywords: Total Harmonic Distortion; Modulation Index; Pulse width modulation.