一种新的谐波电流检测方法

Novel Harmonic Current Detecting Algorithm

有源电力滤波器要求能够实时、准确地检测出电网中实时变化的谐波电流。针对现阶段对电网谐波电流检测方法中普遍存在的时延、计算量大等不足,提出了一种基于瞬时无功功率理论的改进ip-iq变换法。该方法的特点为:省去了传统ip-iq变换中三相到两相的变换及其反变换,使计算过程大大简化;利用单相电压构造同步旋转角,不管在三相对称系统还是不对称系统中都能有效检测出电网谐波电流;不需要锁相环电路就可以获得得同步旋转角,消除了传统ip-iq变换过程中锁相环带来的影响。仿真与实验结果表明,该算法能有效提高系统的实时性、目标跟随能力,更适合于有源电力滤波器的工程应用。

Real time and accurate reference current signal is vital for active power filter（APF）. So, a lot of method for harmonic current detecting have been proposed to improve the performance of active power filter. To avoid some shortages which exist in the harmonic current detecting methods now, such as time delay, large computation, and so on, an improved ip-iq algorithm based on instantaneous reactive power theory is presented. At first, this algorithm can simplifier the computation by omitting the process of changing between three phase and two phase. At second, this algorithm can detect the harmonic current effectively not only under the balanced power system, but also under the Unbalanced power system too. At last, this algorithm can obtain the synchronous rotary angle used in the ip-iq transformation algorithm by using the single phase voltage, so eliminates the influence brought by the time delay of PLL when using traditional ip-iq transformation algorithm. Simulation and experiment results validate that the proposed algorithm can enhance not only the real time response of active power filter, but also its current tracking effect, and suits to the APF＇s engineering application more.