基于改进下垂法的逆变器并联控制技术

针对低压微电网下并联逆变器在容量比和线路阻抗比不一致的条件下无法实现功率合理输出的问题,结合传统下垂方法提出了一种改进的控制策略。首先通过添加虚拟阻抗解决了传统下垂控制在低压微电网下不适用的问题,并且用无功功率输出比例关系和电压幅值限制的约束条件确定了最佳虚拟阻抗值。再通过添加电压降落补偿项、积分和微分环节以及电压动态反馈环节实现了逆变器功率的合理精确输出。通过仿真验证,该策略不仅能够完成功率的合理输出,同时在增加负载时响应迅速,具有较高的动态响应速度。

Parallel Control Technology of Inverters Based on Improved Droop Control

An improved control strategy in combination with the traditional droop method is proposed to solve the problem that the parallel inverters in low-voltage microgrid cannot achieve reasonable power output when the capacity ratio and line impedance ratio are inconsistent. Firstly, the problem that traditional droop control is unapplicable under low-voltage microgrid was solved by adding virtual impedance, and the optimal virtual impedance value was determined by the restriction conditions of the proportional relation of reactive power output and the voltage amplitude limit. Then, a reasonable and accurate output of inverter power was realized by adding voltage drop compensation items, integral and differential links, and voltage dynamic feedback links. Through simulation verification, this strategy can not only achieve reasonable power output, but also responds quickly when increasing the load, and has a high dynamic response speed.