System Control of Power Electronics Interfaced Distribution Generation Units

Unlike conventional power system, the system voltage and frequency of some renewable energy resources based stand-alone distribution generation (DG) system maybe controlled by power electronics converters. This paper presents the control of parallel operation multi-converters in a DG system. The investigated stand-alone DG system is constructed by two local DG subsystems; in each of them, two power electronic converters operation in parallel. A hybrid control scheme is developed to control the system voltage and frequency, hence achieves the load sharing between two DG subsystems and between the converters in each DG subsystem. The LCL filters are designed to filter out the high frequency components from the converters. The simulation results show that it is possible to use power electronics interfaced DG system to supply quality power