Research on Improved Droop Control Based on Virtual Impedance Compensation Strategy

With the application of new power equipment such as hydropower, photovoltaic, and wind power, as well as the promotion of the “oil to electricity” policy for large equipment such as the petroleum, mining, and automotive industries, the demand for megawatt level high-power power sources is becoming increasingly urgent. However, due to hardware limitations such as reactors, transformers, and IGBT, the development of large-capacity individual power supplies is constrained, while multiple power modules can be expanded in series and parallel according to power requirements, providing a new approach for the design of large-capacity power supplies. Focus on the problem of current inequality and bus voltage fluctuations during load disturbances in the parallel operation of high-power DC power sources, an improved droop control algorithm based on a high-pass filter virtual impedance compensation strategy was proposed. The simulation and experimental results show that the improved droop control algorithm achieves current sharing control when high-power DC power sources are operated in parallel, and effectively improves the dynamic characteristics under load disturbances.