基于叠加频率的直流微电网改进下垂控制策略研究

RESEARCHON IMPROVED DROOP CONTROL STRATEGYOF DC MICROGRID BASED ON SUPERIMPOSED FREQUENCY

提出一种基于叠加频率的直流微电网改进下垂控制策略。首先,通过在变换器输出电压上叠加交流电压,构造交流电压频率和输出电流之间的下垂特性;同时,利用交流电压产生的无功功率调节各变换器输出电压,实现电流的精确分配;然后,通过引入虚拟电阻和电压二次补偿措施,实现母线电压恢复同时提高系统稳定性。该文所提控制策略无需通信网络,有效提高了微电网即插即用性能。最后,通过仿真验证了控制策略的可行性和有效性。

This paper proposes an improved droop control strategy for DC microgrid based on superimposed frequency. First,the AC voltage is superimposed on the output voltage of the converter to construct the droop characteristics between the AC voltage frequency and the output current. At the same time,the reactive power generated by the AC voltage is used to adjust the output voltage of each DG converter to achieve accurate current distribution;Then,through the introduction of virtual resistance and voltage secondary compensation measures,the bus voltage is restored and the system stability is improved. This control strategy does not require a communication network,and effectively improves the plug-and-play performance of the microgrids. Finally,the feasibility and effectiveness of the control strategy are verified through simulation.