Investigation of Various PWM Techniques for Solar Powered Three-Phase UPS Inverter Application

This paper proposes to investigate Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM) techniques for control of solar powered Uninterruptible Power Supply (UPS) inverter applications. An inverter system with Pulse Width Modulation (PWM) is used to generate a pure sinusoidal AC output voltage when the utility power is not present. PV array is interfaced with DC/DC converters to obtain the desired DC voltage by utilizing Maximum Power Point Tracking (MPPT) technique to extract the maximum power, which is converted to alternating current (AC) by an inverter. Inverters are also the most critical components in UPS systems which provide power for sensitive equipment when the utility suffers from power quality problems. The most significant factors affecting the overall performance of the system are the power converter topology and the control or modulation strategy used with an LC output filter. The inverter is operated with a pulse width modulated strategy under feedback control to realize the desired output waveform. The dq voltage regulator-based controller is designed, developed and validated through Matlab/Simulink toolbox. The simulation results demonstrate the effectiveness of the control technique with various PWM techniques for inverters in UPS applications. The study reveals that in the context of closed loop control with the SVPWM technique, there is only a minor improvement in Total Harmonic Distortion (THD).