Resonant controllers for 4-leg matrix converters

Variable speed diesel generation is a good alternative to supply electrical energy to stand-alone unbalanced loads. Operating the diesel engine at variable speed reduces the fuel consumption, increases the overall efficiency, reduces the thermal signature of the machine and increases the useful life of the engine. Moreover, to reduce the size and weight of the whole generation system, a Matrix Converter (MC) can be used. However, to interface a MC-based generation system to an unbalanced 3Φ stand-alone load, a four-leg MC is required to provide a path for the zero sequence load current. In order to regulate balanced voltages into the unbalanced load, a closed loop control system is required to compensate for the voltage drops in the output filter inductances and semiconductor devices and to compensate for the non linearities introduced by the commutation method. In this paper the design and implementation of a resonant control system for 4-leg MCs is presented. Simulation and experimental results, obtained from a prototype, are discussed.