一种低延时鲁棒功率下垂控制方法

在分析多逆变器并联功率分配机理上,提出一种低延时鲁棒功率下垂控制方法。通过重新设计等效输出阻抗呈阻性,将下垂控制器中有功/无功功率进行解耦。在此基础上,对有功功率控制构造积分器1/s,设计Q-f/P-U'鲁棒下垂控制器及U'恢复机理,提高了逆变器输出功率对等效输出阻抗和线路阻抗的鲁棒性,解除了线路阻抗与功率制衡关系,实现了负荷功率按额定容量比精确分配。该策略未改变逆变器等效输出阻抗的相频特性,无需重新设计等效输出阻抗,降低了设计难度。同时,利用所提的低延时快速功率计算方法降低了功率计算引入的控制延时,提高了系统的动态性。仿真和实验均验证了所提方法的正确性和有效性。

A Low-Delay Robust Droop Control Method

On the basis of analyzing parallel multi-inverters’power distribution mechanism,this paper pro-poses a low-delay robust droop control method. Through redesigning the equivalent output impedance of the invert-ers as the pure resistance,it can decouple the active/reactive powers in the droop controller. Then,by construc-ting integrator 1/s in active power control,the Q-f/P-U'droop controller and U'recovery mechanism is proposed to improve the robust of the output power against the line impedance and equivalent output impedance. Thus the parallel multi-inverters can share the load power with regard to the ratio of their rated capacities accurately. In additional,considering the phase characteristic of equivalent output impedance is unchanged in this method,it does not need to design the equivalent output impedance again and reduces the design difficulty. Moreover,the system dynamic can be improved by the least-mean-square adaptive algorithm,which reduces the control hystere-sis of the power calculation. Finally,simulation and experimental results verify the validity of the proposed strategy.