Design of SPWM Unipolar (Single Phase) Inverter

In this paper, a design and development unipolar SPWM switching strategy is presented for single phase full bridge inverter. The main advantage of this strategy is that it does not required additional circuit. To obtain the unipolar SPWM switching pulses generated with carrier frequency of 2 kHz and the modulation ratio change from 0.5 to 0.7 by varying amplitude of modulating signal. In the unipolar single phase SPWM microcontroller-based 300VA inverter is designed and tested for fixed modulation index with unipolar voltage switching. The gate pulses waveforms are observed on DSO, The outputs voltage and current %THD waveforms for variable AC voltages and modulation index are observed on DSO, and also see the THD. The pulse width modulation inverter has been the main choice in power electronic for decades, because of its circuit simplicity and rugged control scheme SPWM switching technique is commonly used in industrial applications.