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为提高单相动态电压恢复器(dynamic voltage restorer,DVR)的补偿性能,提出一种基于等效基波及奇次谐波谐振器组的数字控制方法。采用可等效为一组谐振器的延时模块,能够有效抑制电网基波和谐波扰动。给出一种包含两个控制参数和一组零相移陷波滤波器的结构及其设计方法,使系统在保证稳定性的同时,获得较大的谐振增益。其中,延时环节衰减系数可增加谐振器组鲁棒性;控制器比例增益可解决零相移陷波器中使用延时带来的问题;零相移陷波器组既能对消LC谐振峰,也能解决等效谐振器组高增益在高频处的稳定性问题。同时,引入电源电压和负载电流双前馈来保证响应速度,增加了对扰动的抑制能力。所提控制策略结构简单,谐波补偿能力强,动态响应快,易于实现。在2kW单相DVR实验装置上的实验结果验证了该控制方法的正确性。
In order to improve the compensation performance of single-phase dynamic voltage restorer (DVR), a digital control method based on equivalent fundamental and odd harmonic resonators is proposed. Using a delay module that is equivalent to a set of resonators, it effectively suppresses fundamental and harmonic disturbances in the grid. A structure containing two control parameters and a set of zero-phase-shift notch filters is presented and the design method is given. The system can obtain larger resonance gain while guaranteeing stability. Among them, the delay time attenuation coefficient can increase the robustness of the resonator group; the proportional gain of the controller can solve the problem caused by the delay in the zero-phase shift notch filter; the zero-phase shift notch filter group can not only cancel the LC resonance The peak also solves the stability problem of the high gain of the equivalent resonator set at high frequencies. At the same time, the introduction of dual power supply voltage and load current feed-forward to ensure that the response speed, an increase of the ability to inhibit the disturbance. The proposed control strategy has the advantages of simple structure, strong harmonic compensation capability, fast dynamic response and easy implementation. The experimental results on the 2kW single-phase DVR experimental device verify the correctness of the control method.