直流微电网电压等级的选择及其稳定控制策略研究

针对直流微电网电压等级的选择与确定，在已有直流标准和直流工程电压等级基础上，考虑微电网容量和供电半径，进行运行损耗计算，从而选择最优的直流母线电压等级。针对直流微电网电压稳定控制，并网运行时采用储能DC/DC变流器控制直流母线电压稳定，AC/DC逆变器控制直流微电网并网功率。孤岛运行时采用储能DC/DC变流器控制直流母线电压稳定。在PSCAD/EMTDC中搭建直流微电网仿真模型，进行不同运行模式下的电压稳定控制策略仿真验证。结果表明，所采用的电压稳定控制策略，在光伏发电功率和负荷功率波动的情况下，能很好地控制直流微电网电压稳定。

Research on the voltage level selection and its stability control strategy of DC microgrid

In order to select and determine the DC microgrid voltage level, on the basis of the voltage level for existed DC standards and DC projects, considering the capacity and power supply radius of the microgrid, this paper calculates run loss of the DC microgrid to select the optimal voltage level of the DC bus. For the voltage stability control of DC microgrid, in grid-connected operation, the battery DC/DC converter is used to control the voltage stability of DC bus, and the AC/DC converter is used to control the grid power of DC microgrid. In islanded operation, the battery DC/DC converter is used to control the voltage stability of DC bus, too. The simulation model of DC microgrid in PSCAD/EMTDC is established to verify the voltage stability control strategy on different operation modes. The results show that the control strategy can control DC microgrid voltage stability in the case of PV power and load power fluctuations. This work is supported by Key Special Project of Smart Grid Technology and Equipment of National Key R & D Plan (No. 2016YFB0900601).