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传统硬件锁相环无谐波畸变抑制能力且只能跟踪单相电压相位,无法有效提取三相正序分量相位的信息。文中为了适应三相电网的数学模型,将传统的变步长最小均方根算法从单输出系统扩展到多输出系统,提出一种三相幅相锁相系统。该系统根据电网电压谐波含量可自适应地调整步长值,从而实现了对谐波干扰有较好的抑制能力;同时,在电压突变等异常情况,对步长值进行重置,提高了对异常情况的处理速度,从而对于电压暂降等场合具有较快的响应速度。实验结果表明,该幅相锁相系统不仅具有较好的谐波和三相不平衡适应能力,而且能近乎无延迟地反映三相系统正序电压分量幅值和相位的变化,可广泛运用于与三相电网相连的电力电子装置。
The conventional hardware phase-locked loop has no harmonic distortion suppression capability and can only track the single-phase voltage phase, so that the phase information of three-phase positive sequence components can not be effectively extracted. In order to adapt to the mathematical model of three-phase power system, the traditional variable step size minimum root mean square algorithm is extended from single-output system to multi-output system. A three-phase amplitude-phase locking system is proposed. The system adaptively adjusts the step value according to the harmonic content of the power grid so as to achieve better suppression of harmonic interference. In the meantime, the step value is reset in an abnormal situation such as a sudden change in voltage and the like On the exception of the processing speed, and thus for voltage sag and other occasions with faster response speed. The experimental results show that the phase-locked system not only has better harmonic and three-phase unbalance adaptability, but also can reflect the changes of amplitude and phase of the positive sequence voltage components of the three-phase system almost without delay, which can be widely used in Power electronics connected to the three-phase grid.