单侧并联储能变流器并网谐振机理分析及抑制方法

Grid-connected Resonance Mechanism Analysis and Suppression Method of Unilateral Parallel Energy Storage Converter

为解决单侧并联储能变流器并网谐振问题,对谐振机理进行分析,设计抑制方法。通过研究系统待机与运行工况下的幅相参数,获取谐振特性。将谐振成因分为内因与外因,内因为并联系统输出电流随并机叠加,在并网阻抗上产生谐波压降,导致的电压谐波放大。外因为网侧所含背景电压谐波与并联系统阻抗频率在某些频段重叠。随并机数量增加,系统谐振点频率将降低。采用设计的电压谐波补偿单元进行功率解耦及动态多比例谐振控制器进行控制解耦两种方法,实现谐振抑制。通过仿真验证了谐振成因机理及抑制方法有效性。

In order to solve the problem of grid-connected resonance of unilateral parallel energy storage converter,the resonance mechanism is analyzed,and the suppression method is designed.By studying the amplitude and phase parameters of the system under standby and operating conditions,the resonance characteristics are obtained.The resonance causes are divided into internal and external causes.The internal cause is that the output current of the parallel system is superimposed with the parallel machine,and the harmonic voltage drop is generated on the grid-connected impedance,resulting in voltage harmonic amplification.The external cause is that the background voltage harmonics contained on the grid side overlap with the impedance frequency of the parallel system in some frequency bands.With the increase of the random number,the frequency of the system resonance point will decrease.The designed voltage harmonic compensation unit is used for power decoupling and the dynamic multi-proportional resonant controller is used for control decoupling to achieve resonance suppression.The mechanism of resonance and the effectiveness of the suppression method are verified by simulation.