基于自调节下垂系数的微电网控制策略

Control strategy of micro-grid based on self-adjustable droop coefficient

在微电网中,当R?X时,传统的下垂控制方法并不完全适用。分析得出:在低压微电网中,电压幅值决定换流器输出的有功功率,但电压为局部变量,在线路阻抗不同和负荷需求突变的情况下,各DG有功功率不能合理分配;为此,提出一种自调节下垂系数的控制策略,下垂系数随线路阻抗和负荷的变化而自动调整,从而实现有功功率的合理分配;仿真分析结果表明:在DG并联运行时,线路阻抗不同和负荷变动的条件下,该方法可以实现有功功率的合理分配,提高了微电网系统的稳定性。

The traditional droop control method can not fully applicable in the case of R〉〉X in micro-grid. This paper presented that the active power of the inverter output was determined by the amplitude of voltage in low voltage micro grid. Whereas, the voltage is a local variable, the active power can not be distributed reasonably under the condition of different line impedance or mutational load demand. Thus, a self-adjustable droop coefficient control strategy was proposed in this paper, and the droop coefficient could be automatically adjusted with the change of line impedance and load. A simulation model on MATLAB/Simulink was established to verify the effectiveness of the proposed control strategy, and the simulation results show that the proposed strategy can achieve the reasonable distribution of active power on the condition of the different line impedance and mutational load demand when DGs are in parallel, which can improve the stability of micro-grid.