改进广义积分器在三相基波正序有功电流检测中的应用

Application of Improved Generalized Integrator in Three-Phase Fundamental Positive-Sequence Active Current Detection

在低压配电网中,四桥臂有源电力滤波器要求快速、准确地检测基波正序有功电流,传统的基于瞬时无功功率理论的i_p-i_q和FBD(Fryze-Buchholz-Dpenbrock)检测法通过采用锁相环和低通滤波器来实现,这会增加算法的复杂度,并导致较大的检测延时。提出一种基于改进广义积分器的三相基波正序有功电流检测算法。首先,根据广义积分器的选频特性,在传统的基波正序检测方法基础之上增加正负序分离运算模块,构成基于改进广义积分器的基波正序检测方法;然后,运用该算法检测电网电压和电源电流的基波正序分量,并通过简单投影运算,可以快速求得三相基波正序有功电流。该方法省略了低通滤波器环节,具有较强的抗干扰能力和频率自适应性。实验测试结果表明:该算法在电网电压畸变和电网频率波动时检测出的三相基波正序有功电流的谐波畸变率均在2.0%以下,而且还具有较小的动态响应时间(15 ms)。

In low voltage distribution network, rapid and accurate detection of fundamental positive-sequence active current is required for four-leg active power filters. Traditional methods need to use phase-locked loop and low-pass filter, possibly increasing algorithm complexity and delay time accordingly. For this reason, a novel detection method of three-phase fundamental positive-sequence active current was proposed. Firstly, by analyzing frequency selective characteristics of generalized integrator, a positive and negative sequence separation operation module was added to traditional method of fundamental positive sequence extraction. A novel fundamental positive-sequence component extraction method based on improved generalized integrator was obtained. Then, fundamental positive-sequence components of grid voltage and source current were extracted with this method. Through simple mathematical operations, three-phase fundamental positive-sequence active current was obtained. No low-pass filter is needed in this method. Besides, this method has stronger anti-jamming capacity and frequency adaptive property. Finally, experiment result validates that harmonic distortion rate of three-phase fundamental positive sequence active current detected is lower than 2.0% and this algorithm has smaller dynamic response time（15 ms）.