基于同步坐标变换的三相不对称系统的无功与谐波电流的检测

针对现有的一些检测方法在三相电压不对称或畸变时存在的一些缺陷，提出了一种新的基于同步坐标变换的检测方法。它能实时检测出不对称三相电路中的基波正序有功电流以及无功电流与不对称分量、谐波电流的和，从而可直接应用于三相三线或四线系统的综合补偿。该检测方法在三相电压不对称且含畸变时，无须对三相电压进行锁相和滤波，避免了由此带来的检测误差。理论推导和仿真结果验证了所提方法的正确性。

DETECTION FOR REACTIVE AND HARMONICS CURRENTS OF UNBALANCED THREE-PHASE SYSTEMS BASED ON SYNCHRONOUS REFERENCE FRAME TRANSFORMATION

In this paper, limitations of some existing detecting methods for reactive and harmonics currents in the case of unbalanced or distorted three-phase voltages is discussed, then a novel detecting method is presented based on synchronous reference frame transformation. The proposed method can be used to detect positive fundamental active currents and the sum of positive fundamental reactive currents, unbalanced components and harmonics, thus can be adopted to compensate reactive power, unbalanced currents and harmonics for three-phase three-wire or four-wire systems directly. In the case of unbalanced and distorted three-phase voltages, the presented method does not need band-pass filter and phase-locked loop for three-phase voltages; thereby the associated detection error can be avoided. The theoretical analysis and simulation verify the feasibility and correctness.