摘要
高比例新能源接入的直流微电网已经成为研究的热点之一。针对直流母线电压控制问题,首先基于反馈线性化的方法对DC/DC双向换流器在升压和降压两种工作模式下分别进行了非线性建模,并分析了非线性系统一阶零动态的稳定性。然后针对所建立的非线性数学模型,提出了一种应用于DC/DC双向换流器的时间-状态协调最优控制策略。该控制策略分别选取时间最短和二次性能最优为性能指标,设计了时间最优控制器和最优状态调节器。为进一步实现两种控制器间互补协调,基于模糊控制理论引入自适应权重系数,以协调两种控制器间分配的比例,从而实现兼顾状态转移时间和状态调节过程双重优化目标的目的。最后,在MATLAB/SIMULINK中搭建了直流微电网仿真模型,验证了所提控制策略的有效性和可行性。
DC microgrid with high proportion of renewable energy sources becomes a hot spot in field of microgrid. To maintain stability of DC bus voltage, nonlinear modeling of DC/DC bidirectional converter under two working modes was carried out. And then stability of the first-order zero dynamics of nonlinear system was analyzed. Based on the nonlinear mathematical model, a optimal coordinated time-state control strategy for DC/DC bidirectional converter was proposed. The control strategy took time and quadratic function as performance index, and designed time optimal controller and optimal state regulator respectively. In order to further realize coordination between the two controllers, an adaptive weight coefficient based on fuzzy control theory was introduced to coordinate proportion between the two controllers. The proposed strategy took both state transition time and state adjustment process into account and achieved double optimization goals. Finally, a DC microgrid simulation model was built in MATLAB/SIMULINK to verify effectiveness and feasibility of the proposed control strategy.
出处
《电网技术》
EI
CSCD
北大核心
2018年第1期41-47,共7页
Power System Technology
基金
国家863高技术基金项目(2015AA050104)
国家自然科学基金项目(51577068,51607069)~~
