Intelligent grid-interactive single-phase inverter

Abstract

This work presents the design and implementation of a Sinusoidal Pulse Width Modulation (SPWM) single phase grid-interactive inverter with the ability to operate both in stand-alone and grid-connected modes. The proposed design consists of a Voltage Source Inverter (VSI), single power stage full-bridge topology with a low frequency (LF) transformer connected at the output. The inverter is fully controlled by a Digital Signal Processor (DSP) and this enables its seamless connection and disconnection from the grid with uninterrupted power supply to the load. Sinewave voltage with low total harmonic distortion, when in stand-alone mode, and the ability to control the power factor, when in grid-tied mode, are both critical factors for a high-performance system. The design process of such a device is analyzed. A MATLAB/Simulink model of the system has been developed and used for simulations and testing and a full-scale 5kW prototype has been built for testing in real operating conditions.