基波相位和频率的高精度检测及在有源电力滤波器中的应用

HARMONIC AND REACTIVE CURRENT DETECTION IN APF BASED ON HIGHACCURACY PHASE AND FREQUENCY DETECTION

该文提出了一种电力基波频率和相位的高精度数字化实时检测方法,提出了基于高精度基波相频实时检测的有源电力滤波器谐波和无功电流的检测方法。相位检测是基于三角函数正交性及自适应滤波的原理构造了相位跟踪的闭环控制回路,结合延时反馈及变参数 PI 控制技术,使初相跟踪检测的精度达到(10-4)o^(10-10)o的数量级;基波频率的测量是基于初相跟踪检测控制系统的基础之上,求取稳态时初相修正量的时间变化率,即可作为频率跟踪的反馈。在有源电力滤波器中,利用该方法可以求取电压和电流的基波相位频率和相应基波的单位正弦函数,基波幅值用滑窗傅立叶变换的方法求得,从而方便精确地检测出有功和谐波电流。仿真与实验结果证明了所提方法的正确性和有效性。

A real-time digitalization method with high- accuracy and quick detection on power fundamental wave’s phase and frequency is proposed, and a harmonic and reactive currents detection method in active power filter (APF) is proposed. Based on the principle of trigonometric function orthogonality and adaptive filter, a phase-lock control loop is constructed, meanwhile, delayed feedback and parameter- variable PI control technology is used, experiment results show magnitude order of phase-lock accuracy can be up to (10-4)o~ (10-10)odegree, and its response time is about 30ms^200ms. Frequency detection of power fundamental wave is based on the control loop of phase-lock; the variance ratio of phase correction under steady state is regard as the frequency correction signal. In active power filter, the phase or frequency of power voltage and current fundamental wave can be detected by the proposed method accurately, the unit sine function in- phase with the fundamental wave of voltage and load current can be obtained; The amplitude of the fundamental wave can be obtained based on the sliding-window Fourier analysis, and then the reactive or harmonics current can be easily checked out accurately. The simulation and experiment results show its validity and feasibility.