基于改进型统一电能质量调节器结构的微电网控制策略

摘要

A control strategy based on improved structure of unified power quality conditioner(UPQC)is proposed for 380 V three-phase four-wire microgrids.The strategy can effectively compensate voltage sags,voltage swells and voltage distortion, as well as voltage power quality problems caused by nonlinear and unbalanced loads in the microgrid.Grid-side converters (including series converter and parallel converter) can compensate grid voltage and current,which not only solves the coupling interference from series and parallel converters,but also achieves proper load power distribution in the microgrid.An improved minimum-energy compensation method is proposed by improving the UPQC structure at the point of common coupling, overcoming the disadvantages of traditional compensation algorithm and ensuring no phase mutation of load voltage.It not only improves voltage compensation ability and range of distributed generators,but also reduces the capacity and cost of converters. MATLAB/Simulink simulation results verify the effectiveness of the proposed method.%在电压等级为380 V的微电网应用中，针对主电网三相四线制结构，提出了一种基于改进型统一电能质量调节器(UPQC)结构的微电网控制策略。该策略可以有效补偿主电网电压跌落、过电压和电压畸变，以及由微电网中非线性和不平衡负荷带来的电能质量问题。并网变流器(包括串并联变流器)在补偿电网电压和电流的同时，不仅解决了串并联变流器耦合带来的干扰，而且实现了微电网合理的功率分配。通过改进微电网公共连接点的UPQC结构，提出了改进型最小能量电压跌落补偿法，克服了传统补偿算法的缺陷，确保负载电压不会发生相位突变，不仅提高了分布式电源补偿电压的能力和范围，而且降低了变流器的容量和成本。通过MATLAB/Simulink 仿真验证了所述控制策略的有效性。