Development of a Single Phase SPWM Microcontroller-Based Inverter

This paper presents the development of single phase sinusoidal pulse width modulation (SPWM) microcontroller-based inverter. The attractiveness of this configuration is the used of a microcontroller to generate sinusoidal pulse width modulation (SPWM) pulses. Microcontroller is able to store the required commands to generate the necessary waveforms to control the frequency of the inverter through proper design of switching pulses. The SPWM technique was used to produce pure sinusoidal wave of voltage and current output. This inverter is designed to be either for stand-alone or for grid connected from a direct supply of photovoltaic (PV) cells. In this paper SPWM switching technique is first reviewed. Subsequently control circuit and power circuit for inverter are discussed. Finally the experimental results are discussed. The 200W designed prototype of the inverter was tested with the resistive load and found that total harmonic distortion (THD) is less than 4 % for voltage and 8 % for current.