微电网在孤网运行时，至少需要一个电源工作在主控模式下，如恒压恒频（V/f）或带下垂特性的控制方式，从而平衡微电网的功率和电压。主控模式下，当逆变器电源输出的功率越限时，需转为非主控模式，如恒功率（PQ）或倒下垂控制方式，而由另外一个微电网逆变器电源接替主控任务。本文提供了一种具有滞回特性的微电网逆变器电源，可等效增大主控电源的控制能力。若采用多个该型逆变器电源，可设置不同的门槛值，使得各个逆变器电源之间可以按照预先设定的阈值平衡微电网的负荷波动，有更好的调节特性，且不需要通讯支持。%For the isolated micro-grid, there should be at least one invertor which works in master mode, such as constant-voltage constant-frequency mode or droop control mode, to hold on the voltage and frequency stability of micro-grid. If the converter in master mode output power over-limited, it will change to slave mode, such as constant-power mode or inverse-droop control mode. Meanwhile another converter with reversed power will change to master mode. This paper proposedan invertor with hysteresis characteristic, which is equivalent to increase control ability of master inverter. If a micro-grid with more than one inverters like this, they can balance the load fluctuations according to the pre-set threshold. The micro-grid will have better adjustment feature and not need communication support.
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