基于2对Hilbert移相滤波器的无功功率测量方法

基于1对Hilbert移相滤波器实现的无功功率测量方法存在移相误差对测量准确度影响大、中间信号纹波较大等问题。基于2对相同Hilbert移相滤波器的改进方法能够解决这些问题。通过消除误差公式中关于移相误差的一次项形式，削弱了Hilbert滤波器移相特性对测量准确度的影响，从而降低了滤波器的阶次;当测量纯正弦电路或含较少谐波的正弦电路的无功功率时，中间信号的纹波也显著降低。仿真实验对比结果表明，改进方法具有滤波阶次低、系统误差小和中间信号波动小的优点。改进的无功测量方法已经应用于一款数字化电能计量专用芯片的设计。

Method of Reactive Power Measurement Based on Two Pairs of Hilbert Digital Filters

The classical method of reactive power measurement based on one pair of Hilbert filters has some shortcomings such as the accuracy considerably dependent on phase-shift error, the ripples of the intermediate, signal. An improved method using two pairs of Hilbert filters can solve these problems. By eliminating the linear term of the phase-shift error in the error estimation equation, the improved method decreases the effect of the phase-shift characteristic of the Hilbert filters on the measurement accuracy and can be realized with lower order Hilbert filters. In measurement of the reactive power in the pure sinusoidal circuit or the sinusoidal circuit with a few harmonics, the ripples of the intermediate signal are obviously reduced. The simulation results prove that the improved method has the advantages of the lower order filtering, the less system error and the smaller ripples of intermediate signal than ones of the classical method. The proposed novel method has been applied in a design of a digital energy metering integrated circuit.