基于可变虚拟电阻的下垂均流分析与电压补偿

为了解决不匹配的线路电阻和负载动态变化对电流分配和母线电压跌落的影响,提出了基于可变虚拟电阻的改进下垂法,实时采集各并联变换器的电压电流,建立变换器下垂系数与输出电流之间的数学模型,根据所建模型实时改变虚拟电阻,从而达到负载均流的目的。进一步根据不同负载变化情况下母线电压与期望值的误差动态调整母线电压,使母线电压稳定在期望值。最后通过仿真对比分析了传统下垂法和改进下垂法对负载均流和母线电压的调整效果。结果表明,改进下垂法有效降低了均流误差幅度和母线电压跌落幅度。

Droop Current Sharing Analysis and Voltage Compensation Based on Variable Virtual Resistance

In order to solve the influence of mismatched line resistance and load dynamic changes on current distribution and bus voltage sag, an improved droop method based on variable virtual resistance is proposed. The mathematical model of droop coefficient and output of the converter was established by collecting the voltage and current of each parallel converter in real time. According to the built model, virtual resistance was adjusted in real time so as to achieve the purpose of load current sharing. The bus voltage further dynamically adjusted according to the error of the bus voltage and the expected value under different load changes, so that the bus voltage was stabilized at the expected value. Finally, through the simulation comparison, the traditional droop method and the improved droop method were analyzed for the load current sharing and bus voltage adjustment effects. The results show that the improved droop method effectively reduces the current sharing error range and the bus voltage drop range.