基于有源阻尼的微网VSIs并联系统多重谐振抑制方法

A Multiple Resonance Suppression Method for the Micro-Grid VSIs Parallel System Based on Active Damping

针对微网多机组LCL-VSIs并联系统中存在的谐振峰值偏移问题,提出了一种基于有源阻尼的微网VSIs并联系统多重谐振抑制方法。首先,建立微电网单模块、多模块LCL-VSIs系统数学模型,并指出VSI单元中存在内部谐振、并联谐振和串联谐振三部分。分析不同数目机组单元并联运行时对应谐振频率的变化规律。在此基础上,采取电容电流反馈的方式实现有源阻尼多重谐波抑制,并对无差拍电压矢量直接加以修正以保证高带宽。为了验证所提有源阻尼方法的可行性和有效性,搭建了30k W微网VSIs并联系统实验样机。实验结果表明,可对多机组VSIs并联谐振偏移问题有效抑制,并具有足够宽的稳定域度保证了可实现性。

With respect to resonance peak shift in the micro-grid multi-set LCL-VSIs parallel system, this paper proposes a multiple resonance suppression method for the micro-grid VSIs parallel system based on active damping. Firstly, micro-grid single-module and multimodule LCL - VSIs system mathematical models are established, and it is pointed out that internal resonance, parallel resonance, and series resonance exist in the VSI set. Furthermore, the paper discusses the change rule of corresponding resonance frequencies in the parallel operation of different numbers of sets. On this basis, multiple resonance suppression of active damping is realized by means of capacity current feedback, and dead-beat voltage vector is directly modified to assure a high bandwidth. Finally, to verify the feasibility and effectiveness of the proposed active damping method, we build up an experimental prototype for the 30 kW microgrid VSIs parallel system. Test results show that this approach can effectively suppress resonance shift in the muhi-set VSIs parallel system, and its stability domain is wide enough to ensure its realizability.