基于扰动观测器的孤立交直流混合微电网双向AC/DC换流器电压波动控制策略研究

针对孤立交直流混合微电网中双向AC/DC换流器在外界扰动下出现电压波动的问题,设计了一种应用于双向AC/DC换流器的母线电压扰动观测器,以实现在分布式电源出力和负荷功率变化等外界扰动情况下对系统扰动量的快速跟踪,且无需增加额外的电压或电流传感器,保证了交直流混合微电网内分布式电源和负荷的即插即用功能。进一步地提出了基于扰动观测器的孤立交直流混合微电网双向AC/DC换流器电压波动控制策略,以有效抑制暂态电压波动和冲击,提高了孤立混合微电网在不同扰动下的动态响应性能和鲁棒稳定性。在PSCAD/EMTDC平台上搭建了孤立交直流混合微电网仿真模型,通过在不同暂态过程下的仿真测试验证了所提方法的有效性和正确性。

Research on voltage fluctuation control strategy of the bidirectional AC/DC converter in islanding AC and DC hybrid microgrid based on disturbance observer

In view of the voltage fluctuation problem of the bidirectional AC/DC converter in islanding AC and DC hybrid microgrid during external disturbance, a disturbance observer of the bus voltage of the bidirectional AC/DC converter is designed in this paper. With this observer, the system disturbance under the circumstance of external impact such as the abrupt change of distributed generation output and load power can be tracked quickly without additional voltage or current sensors, which ensures the plug and play function of the distributed generation and load in the hybrid microgrid. A voltage fluctuation control strategy of the bidirectional AC/DC converter based on the disturbance observer is proposed further to effectively suppress transient voltage fluctuation and impact, which can improve the dynamic response performance and robust stability of the islanding hybrid microgrid under different external disturbance. The simulation model of the islanding AC and DC hybrid microgrid is established in PSCAD/EMTDC to verify the validity and effectiveness of the proposed method with several transient process cases. This work is supported by National Key Research and Development Program of China (No. 2017YFB0903601), National Natural Science Foundation of China (No. 51777088), and Science and Technology Project of State Grid Hubei Electric Power Company Limited Economic Research Institute (No. SGHBJY00PSWT1700080).