下垂

说明：  下垂控制在逆变器型微电网控制中得到了广泛应用。当线路呈阻性时,有功功率和无功功率存在较强耦合,影响了下垂控制的性能。目前提出了两大类解决方法:一类方法通过控制参数的选取使逆变器的等效输出阻抗在基频段呈感性,但该方法的输出阻抗受制于控制参数并且存在较大缺陷;另一类方法用逆变器输出电流和虚拟阻抗计算电压降,从指令电压中减去该电压降,达到模拟实际阻抗的作用,效果更优,但对其机理缺乏阐述,且存在逆变器输出电压偏差问题。(Droop control is widely used in inverter based microgrid control. When the line is resistive, there is a strong coupling between active power and reactive power, which affects the performance of droop control. At present, two kinds of solutions are proposed: one is to make the equivalent output impedance of the inverter inductive in the fundamental frequency band by selecting the control parameters, but the output impedance of this method is subject to the control parameters and has great defects; the other is to calculate the voltage drop by using the output current and virtual impedance of the inverter and subtract the voltage drop from the command voltage to simulate the actual impedance, The effect is better, but its mechanism is lack of elaboration, and there is the problem of inverter output voltage deviation.)

PQ.slx, 30432 , 2021-01-31