具有电压自恢复特性的独立直流微电网控制策略研究

Control Strategy With Voltage Self-recovery Characteristic for Autonomous DC Microgrid

针对传统下垂控制在母线电压稳定和负荷电流准确分配中存在的问题,提出一种具有电压自恢复特性的独立直流微电网改进下垂控制策略。该策略通过主动测量方法获取线路阻抗信息,并将其以负补偿形式引入下垂系数中用以抑制线路阻抗不一致对电流分配造成的不利影响;同时结合虚拟母线电压信息,利用平移补偿原理实现母线电压稳定运行在额定值。所提控制策略不仅能够在稳态和动态过程中实现负荷电流的准确分配以及母线电压的稳定,而且还能实现二者之间的解耦控制,且其无需互联通信,满足即插即用,极大提高了系统可靠性和可扩展性。最后通过仿真和实验验证了文中理论分析的正确性以及控制策略的有效性。

Aiming at the problems of traditional droop control in bus voltage stability and load current accurate sharing,an improved droop control strategy for autonomous DC microgrid with voltage self-recovery characteristic is proposed.The strategy obtains the line impedance information through the active identification method and introduces it into the droop coefficient in the form of negative compensation to suppress the adverse effect of line impedance inconsistency on current sharing.Besides,with the virtual bus voltage information,the translation compensation principle is utilized to realize the stable operation of bus voltage at the rated value.The proposed control method can not only simultaneously realize accurate load current sharing and the stability of bus voltage in the steady and the dynamic processes,but also can realize the decoupling control between the processes.Moreover,this method satisfies plug and play without interconnection communication,thus greatly improving the reliability and scalability of the system.Finally,simulation and experiment verify the correctness of the theoretical analysis and the effectiveness of the control strategy.