An autonomous harmonic filtering strategy for distributed energy resources converters in microgrid

Distributed generation based on emerging energy technologies has become an attractive alternative to the conventional centralized power stations, and has drawn much interest due to the increasing demand of premium electric power. The microgrid is a great example of integrating distributed energy resources through power electronics interface converters for grid-connected or islanding operation. This paper presents a cooperative harmonic filtering strategy for the interface converters of distributed energy sources to address harmonic issues in a low-voltage microgrid system. A droop control method based on the reactive volt-ampere consumption of harmonics of each interface converter is designed and implemented, to accomplish the overall harmonic filtering workload can be evenly shared among converters without any communications. The operation principle is discussed in details. Computer simulations and laboratory test results are also presented to validate the distributed harmonic damping capability of the proposed strategy.