Analysis of Output Voltage Waveform from Uninterruptible Power Supply Operating at a Rectifier Load

Recently electronic communications equipment including computers and computer-related peripheral units has achieved remarkable growth and diffusion. Since this type of equipment essentially operates on DC power, a rectifier unit is generally used to convert AC power into DC. On the other hand an uninterruptible power supply (UPS) unit used for thr above equipment is designed to guarantee charateristics for a linear load, and consequently there arises a problem of output voltage waveform distortion when a distorted current peculiar to such a rectifier unit is used. In this situation this paper intends to analyze the behavior of the UPS system which is operating at a retifier load and also explain the relationship between the function of LC filter and the emergence mechanism of low harmonic distortion. A PWM inverter of new design is also introduced since it is considered suitable for disposing of rectifier loads.