微电网的电流均衡/电压恢复自适应动态规划策略研究

含多类型分布式电源的微电网已经成为了未来电力系统的重要发展方向,其中风能和光能在降低化石能源消耗和二氧化碳排放等方面有着极大优势,考虑二者之间强互补性的协同调度已被广泛研究.但风/光协同调度的微电网多关注分钟级的调度或优化问题而非风/光波动下秒级的实时电流按容量比例精准分担,简称电流均衡,而精准电流均衡有助于可再生能源的高比例消纳.因此,本文提出了基于自适应动态规划的微电网电流均衡和电压恢复控制策略.首先,构建包含风电整流型电能变换器和光电升压型电能变换器的广义风光拓扑同胚升压变换器模型,其提供了后续控制器设计的模型基础.其次,本文将电流均衡和电压恢复问题转化为最优控制问题,基于此,每个能源主体的目标函数转化为获取最优控制变量和最小电压/电流控制偏差,进而转化为求解哈密顿?雅克比?贝尔曼(Hamilton-Jacobi-Bellman,HJB)方程问题.基于此,提出了基于贝尔曼准则的分布式自适应动态规划控制策略以求取HJB方程的数值解,最终实现电流均衡和电压恢复.最后仿真结果验证了所提分布式自适应动态规划控制策略的有效性.

Research on Current Sharing/Voltage Recovery Based Adaptive Dynamic Programming Control Strategy of Microgrids

Microgrids consisting of different distributed generators(DGs)have become one popular direction for future power systems.Therein,wind energy and solar energy have been regarded as the most promising contributors to reduce fuel consumption and CO₂ emission.Although wind energy and solar energy have been widely studied due to their strong complementarity,the microgrid with wind energy and solar energy coordination schedule system pays more attention on the minute level scheduling,rather than the second level current sharing under wind/solar disturbance.Therein,the accurate current sharing is useful for high proportion of renewable energy.To this end,the accurate real-time current sharing based on their capacity ratio for the microgrid is not achieved.Therefore,this paper proposes an accurate current sharing and voltage recovery control strategy based on adaptive dynamic programming approach in microgrids.Firstly,the generalized wind/solar topological homeomorphism boost converter model with the AC rectifier interface converter of the wind energy and DC boost interface converter of the solar energy is proposed to provide the model basis for subsequent controller design.Secondly,the accurate current sharing and voltage recovery problem is transformed into an optimal control problem.To this end the objective function of each source agent is switched to obtain the optimal controller and minimize the voltage/current control deviation,which is further switched to solve the Hamilton-Jacobi-Bellman(HJB)function.To this end,an adaptive dynamic programming control strategy based on the Bellman principle is proposed to solve the HJB function.The accurate current sharing and voltage recovery can be achieved.Finally,simulation results verify the effectiveness of the proposed distributed adaptive dynamic programming control strategy.