DSP control of high-power UPS systems feeding nonlinear loads

Many facilities, such as patient health care centers, data processing systems, and critical telecommunication links, rely on uninterruptible power supplies (UPS) to maintain a continuous supply of power in case of a line outage. In addition to requiring continuous power, many critical nonlinear loads are sensitive to incoming line transients and input harmonic voltage distortion. Conventional UPS systems operate to protect against such disturbances using complex filtering schemes, often employing large passive components. This paper presents the advantages of using real time digital signal processing (DSP) control of UPS systems. A DSP controlled UPS inverter and harmonic conditioning system is described and the performance is verified on a 150 kVA system.