三电平并网逆变器恒定开关频率的模型预测控制

传统的有限控制集模型预测控制存在开关频率不固定的缺点,这给并网逆变器输出滤波器的设计带来了很大的困难。针对这个问题,提出了一种三电平并网逆变器恒定开关频率的模型预测控制策略。该控制策略将预测最优开关序列控制用于三电平并网逆变器中,并对其寻优方式进行改进。改进的方式是通过找出使目标函数最小的中心矢量来对最优开关序列所在的小扇区进行定位。仿真和实验结果表明,所提控制策略不仅能够在实现定频控制的基础上有效减少计算量,而且具有良好的静态和动态性能。

Model predictive control with constant switching frequency of three-level grid-connected inverter

Traditional FCS-MPC(Finite Control Set Model Predictive Control) cannot provide a constant switching frequency, which brings huge difficulties to the design of output filter. To address this issue, a CSF-MPC(Constant Switching Frequency Model Predictive Control) for three-level grid-connected inverters is proposed. The proposed algorithm applies the predicted optimal switch sequence control to three-level grid-connected inverters, and improves its optimization strategy. This improved method is to locate the small sector where the optimal switching sequence is located by searching the center vector that minimizes the objective function. The simulative and experimental results show that the proposed strategy can not only provide fixed frequency with reduced computation cost, but also exhibit satisfactory static and dynamic performance.