储能型准Z源光伏发电系统级联模型预测控制

Sequential model predictive control for photovoltaic generation systems based on BES-qZSI

针对传统有限集模型预测控制(FCS-MPC)存在权重因子整定繁琐的问题,提出一种级联模型预测控制(SMPC)策略,实现了电池储能型准Z源逆变器(BES-qZSI)光伏并网系统的无权重因子模型预测控制.首先,建立了三相BES-qZSI光伏并网系统的离散化状态空间模型;其次,采用分层优化建立了级联的电抗器电流价值函数、并网电流价值函数和开关频率约束价值函数,通过对其逐级评估寻求最优开关状态,从而避免了传统FCS-MPC所需的综合价值函数及其权重因子,使得控制器设计大为简化.此外,将光伏电池的最大功率点跟踪(MPPT)与电抗器电流控制结合,将储能电池荷电状态(SOC)管理与其过流保护结合,进一步简化了控制结构,改善了控制性能.研究结果表明:SMPC策略控制的BES-qZSI光伏并网系统的控制器不仅设计简化,而且展现了良好的动、静态性能.

Aiming at the problem of cumbersome adjusting for the weighting factors of traditional finite control set-model predictive control(FCS-MPC),a sequential model predictive control(SMPC)was proposed to implement the model predictive control without weighting factor for battery energy stored quasi-Z source inverter(BES-qZSI)based photovoltaic grid-tied system.Firstly,the discrete state-space model of three-phase BES-qZSI based photovoltaic grid-tied system was built.Then,by employing the hierarchical optimization idea,the inductor current cost function,the output current cost function and the switching frequency cost function were respectively established and evaluated in sequence to get the optimal switching state,that the aggregated objective function and its weighting factors required for conventional FCS-MPC were no longer needed,so the controller design was greatly simplified.Moreover,both the integration of PV cell maximum power point tracing(MPPT)control with inductor current control,and the integration of battery state of charges(SOC)management with its over current protection further simplified the controller structure and improved the control performance.The study result shows that the SMPC controller design is more simplifier than that of traditional FCS-MPC,and the BES-qZSI photovoltaic grid-tied system exhibits good dynamic and static performances.