自适应电压补偿的微电网功率均分控制策略

Power Sharing Control Strategy of Microgrid Based on Adaptive Voltage Compensation

微电网在孤岛运行模式下,各并联逆变器额定容量和馈线阻抗存在差异,采用传统下垂控制策略时输出功率难以合理分配,降低了系统的稳定性。针对该问题,对低压微电网功率传输特性进行分析,得出影响功率合理分配的主导因素。提出一种自适应电压补偿的控制策略,通过虚拟阻抗的加入使输出功率合理解耦后,采用实际输出功率与预期输出功率的差,通过功率补偿系数和比例积分控制,进而调节各逆变器的参考电压。该控制策略能够实时跟踪分布式电源输出功率的变化而自动调整,及时调节因线路阻抗不匹配所带来的电压变化,提高了电能质量,减小了系统环流,实现了功率的合理分配。最后,通过仿真模型验证了该策略的有效性。

In the islanding operation mode of the microgrid,the rated capacity and feeder impedance of each parallel inverter are different. In case of adopting traditional droop control strategy,the output power is difficult to be distributed reasonably,which reduces stability of the system. As for this problem,the power transmission characteristics of the low-voltage microgrid are analyzed and the dominant factors affecting the reasonable distribution of power are obtained. A kind of control strategy of adaptive voltage compensation is proposed. After the output power is reasonably decoupled through the addition of virtual impedance,the difference between the actual and the expected output power is used to adjust the reference voltage of each inverter by way of power compensation coefficient and proportional integral control. The control strategy can track in real time the variation of the output power of distributed power sources and adjust automatically,adjust in time the voltage variation due to line impedance mismatch,which improves power quality,reduces system circulation and achieve reasonable power distribution. Finally,the effectiveness of the model is verified by a simulation model.