Modeling and Control of Single-Phase UPS Inverters: A Survey

High performance UPS inverters have stringent control requirements both under steady-state and under transient conditions. Many different control techniques have been applied to UPS inverters. However, there are few publications reviewing the literature on these control techniques and classifying the same, particularly with regard to the more recent developments in this area. In this paper, the control problem of a single-phase UPS inverter is presented and discussed. Both the transfer function and the state-space models of the inverter are presented. Then a review of the most popular solutions for control of UPS inverters is carried out. These control techniques are classified as model-based instantaneous feedback control, feedforward learning control and nonlinear control. The major advantages and disadvantages of these methods are highlighted and compared.