New current control strategy for local converter under distorted grid conditions

This paper proposes a novel current control method for reducing the rms current of converters in the distorted grid. The proposed strategy can reduce the conduction losses of both the local converter itself and the overall power system. In practical, the grid voltage may be distorted by various nonlinear loads. However, the present standards on the current harmonics of individual equipment under the distorted grid conditions are ambiguous because they assume that the grid voltage is purely sinusoidal or includes negligible harmonics. Therefore, this paper considers the distorted condition and mathematically calculates an optimal current of the local converter in this case. The corresponding current control scheme is implemented to a single-phase converter, and the analysis for the effects on the grid by the proposed strategy is also presented in this paper. Experimental results verify the outperformance of the proposed control by demonstrating smaller rms current.