基于鲁棒锁相环的谐波环境下电能计量方法

Electric energy measurement with harmonics based on robust PLL

为解决电网谐波污染造成电能计量表计误差问题,提出了一种基于鲁棒锁相环的谐波环境下电能计量方法。分析了该锁相环的系统结构,并证明系统输出能收敛于外输入信号的基波瞬时幅值和瞬时相位,且它对于输入信号基本频率的小变化是鲁棒的。利用该锁相环能实时跟踪输入的基波分量和总的谐波分量,并能准确获得基波的频率/周期。在此基础上,结合积分平均功率法,可得到基波有功功率、总谐波有功功率,还能得到基波无功、电压总谐波畸变率、电流总谐波畸变率等指标。仿真结果证明该方法在谐波环境下电能计量具有较高的精度,总有功功率误差小于0.2%。

An energy measuring method based on robust PLL（Phase-Locked-Loop） is proposed to reduce the measurement error caused by harmonic pollution of power system. The system structure of PLL is discussed and it is proved that the system output converges at the fundamental instantaneous amplitude and phase of external input signal and the system is robust against the small change of input frequency. The fundamental component and total harmonic component of input signal are followed by PLL in real time and the fundamental frequency is obtained accurately. Combined with the integral average power method, the fundamental active power and total harmonic active power,as well as the fundamental reactive power,total voltage harmonic distortion and total current harmonic distortion are measured. Simulation results show that the proposed method has higher precision of energy measurement in harmonic environment, and the error of total active power is less than 0.2 %.