Simulation of a Single Phase Inverter with Unipolar Voltage Switching Using Sinusoidal Pulse Width Modulation (SPWM) Technique

Abstract

 The choice of the switching techniques used is key to good inverter performance, as it could offer reduced switching losses, generate less EMI, reduce filter size and offer better THD performance. To improve inverter performance these factors must be put into consideration. This Paper presents the Modelling, and Simulation of Single Phase Sinusoidal pulse Width Modulation (SPWM) Inverter With Unipolar Voltage Switching using the SIMULINK toolbox of MATLAB software. In this switching scheme, the high-frequency triangular carrier wave is compared with two sinusoidal modulating signals having the same amplitude and a frequency of 50Hz. The two sinusoids are  180° out of phase. The output is used to switch the two legs of the H-bridge inverter in a complementary fashion. The results obtained from the simulation show an output with the fundamental voltage of 283.4 V at the frequency of 50Hz and a total harmonic distortion (THD) of 64.42 % when the filter was not applied. However, with the incorporation of LC filter the THD was further reduced to 2.7% at the fundamental voltage of 236.6 V. However, Without output voltage feedback control, change in load resistance from 10 Ω to 50 Ω marginally increased the fundamental voltage and percentage THD up to 239.5 V and 4.22%. The experimental setup also presents similar waveforms.