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当三相四线统一电能质量调节器(UPQC)工作于不平衡及非线性条件下时,直流侧电容电压波动不可避免,将直接影响串、并联补偿器的正常变换,进而影响UPQC的补偿性能。文中详细分析了这种波动不可避免的原因,提出了直流电压调节系数的概念,推导出其表达式,分析了利用其消除电容电压波动影响的原理,并将其作为抑制直流侧电压波动的措施应用于带负载电压前馈的并联侧直接电流控制策略和串联侧双闭环控制策略。实验结果表明,采用这种方法可以抑制直流侧电容电压波动对串、并联补偿器的影响,与未加入此种抑制措施的控制策略相比,UPQC的补偿性能得到了提高,表明了这种措施的有效性。
When three-phase four-wire unified power quality regulator (UPQC) works under unbalanced and non-linear conditions, the fluctuation of DC side capacitor voltage is inevitable, which will directly affect the normal conversion of series and parallel compensators, thus affecting the compensation performance of UPQC . In this paper, the reasons for this unavoidable fluctuation are analyzed in detail. The concept of DC voltage regulation coefficient is proposed and its expression is deduced. The principle of eliminating the influence of capacitor voltage fluctuation is analyzed and used as a measure to restrain DC voltage fluctuation It is applied to parallel side direct current control strategy and series side double closed-loop control strategy with load voltage feedforward. The experimental results show that this method can suppress the influence of DC capacitor voltage fluctuation on the series and shunt compensators. The compensation performance of UPQC is improved compared with the control strategy without adding such a suppression measure, which shows that this measure Effectiveness.