四桥臂电压质量调节器及其在微电网中的应用

低压配电网电压跌落、骤升、不平衡、谐波等扰动影响微电网的正常并网运行，为抑制以上配电网电压扰动影响，采用具有综合补偿电压扰动能力的四桥臂电压质量调节器（VQR）。针对VQR的补偿目标，采用一种基于新型谐振PVPI控制器的电压电流双环控制策略，通过提取跌落后电压基波正序分量，将输出补偿量分为跌落（或骤升）补偿部分和用于抵消负序、零序及谐波电压分量部分，利用PVPI控制实现对两部分补偿指令信号的零稳态误差控制。仿真结果证明所提出的四桥臂电压质量调节器有效地补偿了配电网电压扰动的影响，提高了微电网故障穿越能力。

Four-Leg VQR and Its Application in Microgrid

Distribution grid faults such as voltage sags, swells, unbalance and harmonics, affect the normal operation of the micro-grid. To address the issue, a novel four-leg configuration voltage quality regulator（ VQR ） is used to constrain disturbances to the distribution grid voltage. To realize the compensation of the VQR, a double-loop control strategy based on the PVPI control is adopted. Through extraction of the positive sequence component, the compensation value of VQR is divided into two parts： the fundamental positive sequence component of voltage sag or swell and the fundamental negative and zero sequence component and harmonics. The PVPI controller is used to track the reference voltage without zero steady-state error. Simulation results verify that the proposed control strategy can suppress voltage disturbances and improve faults ride-through performance of the micro-grid.