A New Type of Three-phase Asymmetric LCL Power filter for Grid-Tied Voltage Source Inverter

Power filters have been widely used to deal with the switching harmonics issue caused by the modulation of grid-connected inverters. In order to save the total inductance and reduce the volume, different trap filter topologies had been proposed, but it is difficult to balance the elimination of multiple harmonic currents and the poor characteristic to against parameters drift due to complex structure. In this paper, a new simple structure three-phase power filter with the almost smallest total inductance is proposed, which has strong ability to resist parameters drift. The detailed theoretical analysis on the proposed filter is carried out. The simulations and experimental results on a 380 V/ 50 Hz / 6 kW three-phase inverter prototype have also verified the performance of the proposed filter.