Stability analysis and simulation of a single‐phase voltage source UPS inverter with two‐stage cascade output filter

The primary role of an uninterruptible power supply (UPS) systems is to produce sinusoidal output voltage with minimum total harmonic distortion (THD) and fast dynamic response. This paper investigates the performance of two‐stage cascade output filter for single‐phase voltage source UPS inverter and it is compared with an LC output filter. The simulation result shows harmonic reduction of output voltage of the inverter due to using multiple‐filter. Both THD of the low output voltage and good voltage utilization can be achieved by the proposed filter scheme. The THD of the output voltage in various load condition are all less than 4%. A good agreement between the simulation and experimental results is achieved.