Comparison of Performance of Single-Phase Inverter Using Multiple PWM Techniques

Abstract

Inverters – vitally important in photovoltaic, wind energy, uninterrupted power supply, and motor drive systems – have their operation substantially affected by how their output voltage waveforms are made. For single-phase inverters, Pulse Width Modulation, or PWM, is the method most commonly put to work for creating the needed output voltage waveform. PWM methods cut down on Total Harmonic Distortion, and also on switching losses, as well as raising all-around performance. There are a number of PWM methods – single-pulse, multi-pulse, and sinusoidal PWM amongst them – and each has its own way of dealing with harmonics and lessening switching loss. It is, then, really important to pick the correct PWM method to boost the performance of a single-phase inverter. In the work reported here, a large number of simulations were run to assess single-phase inverters with the different PWM methods. Also, tests were done in the lab to look at how well these methods worked. The aim was to find the best PWM method, and the best ways of improving it, for single-phase inverters; the main interest of this study was PWM methods, and how they’re used in single-phase inverters.

Introduction

The document explains the role of inverters in modern energy systems and compares different Pulse Width Modulation (PWM) techniques used to generate clean AC output from DC sources. Since inverter performance depends heavily on switching control, modulation methods directly affect waveform quality, harmonic distortion (THD), efficiency, and filtering requirements.

It discusses several PWM strategies:

• Single-pulse PWM: simple but produces high harmonic distortion and poor output quality.
• Multi-pulse PWM: reduces lower-order harmonics but increases switching losses and shifts distortion to higher frequencies.
• Sinusoidal PWM (SPWM): generates pulses based on a sine reference, significantly reducing low-frequency harmonics and improving output quality, making it the most widely used approach.
• Unipolar PWM: produces lower THD and better waveform quality using three voltage levels but requires more complex control.
• Bipolar PWM: simpler and cheaper but results in higher harmonic distortion due to abrupt voltage transitions.
• Trapezoidal and harmonic-injected modulation: aim to increase fundamental output voltage or reduce losses, but may introduce specific harmonic challenges.

The system is implemented using an ARM7-based microcontroller (LPC2148) to generate SPWM digitally. This allows flexible control of switching frequency and modulation parameters without hardware changes.

A key trade-off in inverter design is between switching frequency and efficiency: higher frequencies improve waveform quality and make filtering easier but increase switching losses. LC filters are used to remove remaining harmonics.

Conclusion

All three methods were tested on the same hardware under the same load. SPWM won, clearly — lowest THD, cleanest output. The other two weren’t competitive for applications that care about waveform quality. Switching frequency is a genuine tradeoff. Higher frequency improves the output; it also stresses the devices. Where you land depends on what the application demands thermally and what THD it can tolerate. For anything where power quality matters — UPS stages, solar inverters, motor drives — SPWM with a properly de-signed LC filter is the answer. These results support that, though the specific frequency selection needs to be worked out for each design.filter is the answer. These results support that, though the specific frequency selection needs to be worked out for each design.

References

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Copyright

Copyright © 2026 S. Guru Kiran Reddy, Sanga Sathwik , Dr. T. Murali Krishna, Elavala Sai Ankith Reddy, Dasyam Sushma. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.