电网电压不平衡及谐波畸变时基波电压同步信号的检测

Synchronizing Signal Detection of Fundamental Voltage Under Unbalanced and/or Distorted Grid Voltage Conditions

提出了一种电网电压不平衡及谐波畸变时基波电压同步信号的检测方法。通过采用一种新颖的谐振式锁相环技术,快速补偿锁相过程中各类电网故障引起的相位跟踪误差,有效地抑制了电网电压中负序及谐波分量引起的频率波动、相位抖动。该方法不仅适用于理想电网条件,更可在各种电压跌落、三相不平衡和谐波畸变等严重瞬态、稳态电网故障下,实现基波电压同步信号的快速检测和电压中基波正、负序分量与谐波分量的分离和提取。仿真与实验结果表明,所提出方法具有检测精度高、实时性好、适应性强和简单实用的特点,可为各种风力发电机组、太阳能光伏并网装置、可逆调速传动系统和动态无功补偿器等并网电力电子设备的运行控制提供有效和可靠的控制基准。

A novel synchronizing signal detection scheme for the fundamental voltage during unbalanced and/or distorted grid voltage conditions is proposed.By adopting a new resonant-type phase locked loop（PLL） design,the phase tracking error caused by the grid faults can be quickly compensated,and the frequency variation and phase jitter can be effectively suppressed as well.This method can be used for detecting the frequency,amplitude and phase of the fundamental voltage under ideal grid condition,as well as the grid fault condition,which is related with the voltage dips,unbalance and harmonic distortion at both the steady state and transient state.Besides,the positive and negative components of the fundamental voltage,and the harmonic components can be separated completely and rapidly.Simulation and experimental results prove that the proposed algorithm is of high precision,fast dynamic response and strong practicability.It provides a reliable foundation for the control of grid connected power electronic devices,e.g.,wind turbine generators,grid-connected converters of solar photovoltaic,reversible variable speed drive system and dynamic reactive compensators and so on.