A single phase uninterruptible power supply system using a bidirectional sinusoidal PWM inverter

This paper presents an uninterruptible power supply system using a bidirectional sinusoidal PWM inverter. This system offers a smooth transition during grid failure, load voltage stabilisation under varying input grid voltage and lower line current harmonic distortion. The inverter maintains the load voltage and the power flow from the grid by controlling its magnitude and phase angle with respect to the grid. Some preliminary results from computer simulation and laboratory testing are presented in this paper.