基于鲁棒电流下垂控制的不同容量逆变器并联控制研究

Power control of paralleled inverters with different power ratings based on robust current droop control

在低压微电网孤岛运行时,等效系统阻抗的特性和大小对于不同容量逆变器并联按其容量成比例精确分担负荷有很大的影响。本文详细分析了系统阻抗呈阻性时不同容量逆变器并联按其容量成比例分担负荷所需要满足的条件,并提出了鲁棒电流下垂控制策略,消除了系统阻抗对于有功电流精确分配的影响。对于逆变器输出阻抗,本文采用电容电压外环准PR调节器和电感电流内环比例调节器的双闭环控制,并且加入了一定的虚拟电阻,使得逆变器的等效输出阻抗呈阻性且可控。通过仿真和实验验证了所提控制策略的正确性和有效性。

When the low voltage micro-grid operate in islanded mode, the characteristics and the size of the equivalent system impedance affect greatly on the load sharing of multi-paralleled inverters with different capacity accurately according to its own capacity.The conditions needed are analyzed in detail in this paper, that multi-paralleled inverters with different capacity share the load accurately w,hen the system impedance is resistance, and proposed a robust current control strategy, eliminating the impact of system impedance on the active current precisely.As for the output impedance of the inverters, The double closed-loop controller are used in this paper, that the capacitor voltage outer loop with quasi proportional resonant regulator and the inductor current inner loop with proportional regulator. Introducing a virtual resistor make the equivalent output impedance of the inverters resistance and con-trolled. Simulation and experimental results verify the correctness and validity of the proposed control strategy.