Simulation of transients in an UPS feeding a computer system

The uninterruptible power supply (UPS) represents a necessary link that provides continuous power supply to any computer system. When designing an UPS for a computer system, the UPS output performance under different probable transient conditions must be thoroughly investigated to assure that it lies within the allowable tolerances given by the computer manufacturers. The simulation package PSPICE is utilized to simulate different transient states of a typical online static UPS system, including regulating feedforward and feedback loops, when feeding a digital computer. With the help of simulation, all components and parameters of the UPS system are adjusted to obtain an output transient behaviour that lies within the allowable tolerance for the computer load. The simulation results are given.