多能互补直流微网电压与能量分层协调控制策略

Research on Hierarchical Coordinated Control Strategy of Voltage and Energy for Multi-Energy Complementary DC Microgrid

直流微网内部的能量协调控制对电能质量和供电可靠性具有重要影响。尤其在孤岛状态下,当缺少交流主网支撑时,网内功率不平衡会引起直流母线电压失稳越限,造成供电质量严重下降,甚至导致系统崩溃。鉴于此,构建了多能互补直流微网模型,通过改进分层控制策略,利用直流母线电压变化因子决定不同控制层下各端变换器的工作状态,解决直流微网母线的电压稳定及能量优化协调控制问题,达到提高系统电能质量和供电可靠性的目的。最后,通过对各运行模式下直流母线电压与功率交换特性的关联例证分析,验证了控制策略在直流微网运行控制中的可行性与正确性。

Energy coordination control of DC microgrid would significantly impact the power quality and power supply reliability. Because of the islanding DC microgrid lacking support with the main grid, an abnormal DC voltage with power imbalance could seriously affect power supply quality, or e- ven cause the whole system collapse. Therefore, a multi-energy complementary DC microgrid model was built for resolving the voltage stability and energy optimal coordination control. Meanwhile, an improved hierarchical control strategy using the DC voltage variation range was utilized. Under any control level, the corresponding operation condition of converters would be autonomously chosen. So, DC microgrid power quality and supply reliability was improved. Finally, the characteristics of DC bus voltage and power exchange were analyzed in the simulations on a DC microgrid in different opera- tion modes. The simulations demonstrate the feasibility and validity of the proposed control strategies.