Power loss reduction and power quality improvement in distribution systems using a modified converter of distributed generation resources

Distribution network is a conventional concept for introducing the distributed generation resources (DG). In this paper, performance of a distributed generation converter is enhanced with the aim of reducing the power loss and improving the power quality. Three basic issues introduced on topics of the grid-connected DG are as follows: 1) compensation of the harmonic contents regarding to nonlinear loads using the converter and avoiding them to be injected into the gird, 2) using the converter to compensate the reactive power load provided from the converter and avoiding the grid to be involved in reactive generation portfolio and 3) reducing the converter related power losses. Satisfying these requirement, power quality is enhanced and also the power loss can be reduced. In order to realize the mentioned factors, a specific structure of power electronic based converter developed by two voltage source inverter is proposed. These two inverters are parallel connected together and supposed to provide grid-connection of a one-phase distribution generation resource. Since the first inverter is operated with a low frequency switching strategy and the second has low magnitude current with high switching frequency, the total power loss will significantly less than that of individual high frequency inverters. The proposed structure is mainly designed to behave as an efficient interface injecting the active power of DG into the grid network. Moreover, this converter acts as an active power filter (APF) that provides a pure sinusoidal current at unity power factor into the network by compensating the harmonic contents and also reactive power required from the load. Consequently, the desired condition is satisfied by the proposed converter and then the power quality and power losses are improved. The performances of the proposed scheme are verified through the simulation analysis in MATALB framework.