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分布式发电系统并网时,需要实时检测电网电压的基波频率和瞬时相位。该文提出基于强跟踪滤波器的单相电压基波相位实时提取方法:首先添加电网电压基波频率和直流偏移作为状态变量,建立含有直流偏移和谐波分量的单相电网电压信号的非线性状态空间描述;其次,考虑到扩展卡尔曼滤波在系统达到平稳状态时无法快速跟踪系统参数突变,采用强跟踪滤波器递推估计各状态变量,并利用状态变量估计值实时计算单相电压信号的基波频率、幅值和相位。实验结果表明,所提相位实时提取方法能够在消除电网电压直流偏移影响的同时快速跟踪电网参数突变。
When distributed generation system is connected to grid, it needs to detect the fundamental frequency and instantaneous phase of grid voltage in real time. This paper proposes a real-time phase and phase extraction method of single-phase voltage based on strong tracking filter. Firstly, the fundamental voltage and DC offset of grid voltage are added as state variables to establish a single-phase grid voltage signal with DC offset and harmonic components Secondly, considering that the extended Kalman filter can not rapidly track the sudden change of the system parameters when the system reaches a steady state, a strong tracking filter is used to recursively estimate the state variables and calculate the single-phase voltage in real time using the state variable estimation value The fundamental frequency, amplitude and phase of the signal. Experimental results show that the proposed phase real-time extraction method can rapidly track the sudden change of grid parameters while eliminating the influence of DC offset of grid voltage.