A new configuration of low cost rotative diesel UPS system

This paper presents a new configuration of rotative diesel UPS system, describes its main characteristics and the experimental results obtained with a prototype of 100 kVA. The new system uses only standard industrial machines and is designed for minimization of cost and power losses. The main components of the UPS are an induction motor, a brushless alternator, a diesel engine and a DC-AC converter, that is used only during the diesel engine starting time. The description of the DC-AC converter operation and of transient problems, that occur in the induction motor during the inverter start, is also presented. A simplified configuration without galvanic isolation where the induction motor is not required, is also considered.