中文摘要：

详细推导了中点钳位型三电平并网逆变器的状态空间模型，并在此基础上提出了一种有限集最优预测（finite set optimal predictive，FSOP）控制方法。该方法将三电平并网逆变器的27个开关矢量组成一个有限集，然后在有限集中选择使罚函数最优的开关矢量，其中的罚函数是由输出电流误差、中点不平衡电压和器件开关次数组成的加权和。文中给出了FSOP控制方法的流程图，并通过仿真和实验评估了该方法的控制性能。仿真和实验结果表明：与传统方法相比，FSOP控制方法的控制目标灵活，通过调整罚函数的加权系数就可以灵活方便地优化逆变器的综合性能；FSOP控制方法避免了传统方法中控制器加调制器的级联结构，在跟踪输出电流参考信号、平衡中点电压方面具有较快的响应速度。

英文摘要：

A state space model for the neutral point clamped three-level grid-connected inverter is derived in detail, based on which a finite set optimal predictive （FSOP） control method is proposed. The proposed FSOP method is used to select the optimal switching vector from a finite set according to a cost function. The finite set is composed of 27 switching vectors, and the cost function is composed of the error of output current, the neutral point unbalanced voltage and the switching time of devices. The flow chart of FSOP control is given and the control performance is assessed by simulation and experiment. Experimental results show that the proposed FSOP method has a flexible control purpose, and the synthetic performance of the inverter can be optimized just by adjusting the weighting coefficients of factors in the cost function. FSOP control has bypassed the structure of controller plus modulator in the traditional control method and has a quick response in tracking the output current reference signals and balancing the neutral point voltage.