一种基于节点比较法的三相四桥臂并网逆变器模型预测控制方法

三相四桥臂并网逆变器在三相四线制系统中得到了广泛的应用。建立了三相四桥臂LCL型并网逆变器的精确模型，采用模型预测控制并综合考虑跟踪误差与开关损耗，求出最合适的开关序列，其效果优于传统控制方法。为了解决运算量大的问题，使用球形译码算法，把代价函数匹配为球形译码的标准形式，同时引入一种新的初始半径选取方法，即节点比较法，进而减小计算量。仿真结果表明，所提方法中电流波形的跟踪误差和谐波失真均满足要求，并有较好的动态响应。

Node Comparison Method Based Model Predictive Control Method for Three-phase Four-leg Grid-connected Inverter

Three-phase four-leg grid-connected inverters have been widely applied to the three-phase four-wire system. In this paper, an accurate model of a three-phase four-leg LCL-type grid-connected inverter is established, and the optimal switching sequence is obtained by using the model predictive control and taking into account the tracking error and switching loss comprehensively, which is superior to the traditional control method. To solve the problem of computation burden, a sphere decoding algorithm is used to match the cost function to the standard form of sphere decoding. Meanwhile, a novel method of initial radius selection(i.e., node comparison method) is introduced to reduce the computation burden. Simulation results show that the tracking error and harmonic distortion of current waveform obtained using the proposed method can meet the requirements, with a good dynamic response.