To solve the problem that the phase angle difference between line voltage and phase current is not considered in non-unbalanced control strategy,the active and reactive current of three-phase cannot be completely compensated,the relationship between the compensation reference current and the load current was deduced based on the phase angle difference.Then,a cross decoupling unbalance control strategy was proposed for two-leg converter,which used multiple variable filter(MVF)and crossing decoupling double complex coefficient filter(DCCF)to optimize the phase-locked loop(PLL),and voltage frequency and phase under three-unbalanced grid voltages were precisely locked.According to the relationship,two single-phase converter was used to compensate three-phase grid unbalanced active and reactive current.The experimental results prove that the proposed control strategy can effectively suppress three-phase unbalanced active current and compensate for three-phase unbalanced reactive current,three-phase current unbalance factor can be reduced from 150.0％to 2.6％,and three-phase grid power factor can be increased from 0.257 to 0.997 under the experimental load conditions.Moreover,the number of switches of three-phase reactive power compensator can be significantly reduced.
关键词
单相半桥背靠背变换器/两桥臂变换器/交叉解耦控制/三相无功补偿
Key words
two single-phase half-bridge converter/two-leg converter/cross decoupling control/three-phase reactive current compensation
维普
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