DC/AC power converter for home scale electricity systems powered by renewable energy

This paper presents the design of a single phase DC/AC Converter or Inverter for home scale electricity systems powered by renewable energy such as photovoltaic system. The power converter is controlled using a microcontroller. The inverter system is firstly modeled and simulated using SPICE, before we design it. A control software, implementing Sinusoidal Pulse-Width Modulation (SPWM) signal generator, is embedded into the microcontroller. The SPWM signal is implemented with a simple on/off set activation based on a scheduled-time. The time schedule is obtained from simulation. This approach results in a simpler program compared to another approach, where sawtooth and sinusoidal signal are compared to obtain the required SPWM signal. The inverter is tested for different load conditions. Using a few load configuration, the THD varies between 1% to 13% depending on the load types and the resistive values on the loads. The inverter output voltage amplitude is also measured, and it changes due to the load changes.