基于混合无源控制的变换器并联研究

Research on the parallel connection of converters based on hybrid passivity-based control

由于线路阻抗的不同和负载的变化,直流微电网中各功率单元会出现电流分配不均和直流母线电压的波动。针对以上问题,在传统无源控制的基础上增加外部电压闭环和线路阻抗补偿电路,提出了一种将无源控制与PI控制相结合的混合无源控制策略。该方法不仅能快速跟踪负载变化且没有静态误差,而且可以有效地提高由于线路阻抗的不同而引起的并联变换器的输出电流分配精度。通过仿真表明,混合无源控制策略相比于传统的无源控制,在负载发生变化时,直流母线电压可以保持稳定,同时也提高了分流精度。通过搭建硬件在环测试的RT-LAB实时仿真平台,进一步验证了混合无源控制策略的可行性。

Due to the difference between the line impedance and the change of the load,the uneven current distribution and the fluctuation of the DC bus voltage will be generated between the power units in the DC microgrid.In order to solve the above problems,this paper proposes a hybrid passivity-based control strategy that combines passivity-based control and PI control.On the basis of traditional passivity-based control,the external voltage closed-loop and line impedance compensation circuit are added.This method can not only track the interference quickly without static error,but also effectively improve the output current distribution accuracy of the parallel converter caused by the difference of the line impedance.Simulation shows that,compared with the traditional passive control,the hybrid passive control strategy can keep the DC bus voltage stable when the load changes,while also improving the shunt accuracy.The effectiveness of the control strategy is further verified by using the RT-LAB real-time simulation platform for hardware-in-the-loop testing.