交直流混合微电网互联变流器新型控制策略

交直流混合微电网是未来电网的发展方向之一。为实现两侧微电网的功率相互支撑，提出了一种新型的互联变流器控制策略。采用双级式互联变流器，解决了在直流微电网电压等级较低时与交流微电网互联的问题，且直流微网电压在较大范围内变化时也可正常运行。针对双级式互联变流器的特点，推导得到交流微网频率与电容电压的数学关系，在功率控制环节采用电压偏差-功率下垂控制策略，实现了两侧子网的功率支撑。PSCAD仿真结果验证了控制策略的有效性。

A New Control Strategy of Interlinking Converter in Hybrid AC/DC Microgrid

The hybrid AC/DC microgrid is one of the development directions of power grid in the future. In order to support each others power in the microgrid on both sides， a new control strategy of interlinking converter is proposed in this paper. A two-stage interlinking converter is used to solve the problem of interconnection between DC and AC microgrids when the voltage level of DC microgrid is low， and the DC microgrid can operate normally even when the voltage varies in a large range. According to the characteristics of the two-stage interlinking converter， mathematical relationship between the frequency of AC microgrid and the voltage of DC capacitor is derived. The droop control of voltage error-power is adopted in the power control loop， and the power support of the subnetworks on both sides can be realized without communication. PSCAD simulation result verifies the effectiveness of the control strategy.