并网逆变器双优化三矢量模型预测电流控制

Double optimization three-vector-based model predictive current control for grid connected inverter

两电平并网逆变器双矢量模型预测电流控制,在单个控制周期中逆变器输出期望电压矢量覆盖范围较小、直交轴电流脉动较大,导致电流跟踪精度不高,并网电流谐波含量较高。针对此问题,采用一种并网逆变器双优化三矢量模型预测电流控制策略,在单个控制周期内采用两次价值函数优化选择出最优矢量组合,应用无差拍控制计算出每个最优矢量的作用时间,并在其出现过调制时进行重新分配。采用矢量插入的控制方式,改变矢量作用顺序,减小电流脉动,提高动态响应速度。搭建了系统仿真模型进行仿真分析。研究结果表明:所提方法有效地减小了系统直交轴电流脉动,降低了入网谐波含量,提高了系统动态响应速度和稳定性。

The dual vector model of the two-level grid connected inverter predicts the current control.In a single control cycle,the expected voltage vector coverage of the inverter output is small and the D-axis and Q-axis current ripple is large,resulting in low current tracking accuracy and large harmonic content of the grid connected current.To solve the problem,an improved double optimization three vector model predictive current control strategy for grid connected inverter is adopted.The optimal vector combination is selected by twice value function optimization in a single control cycle,the action time of each optimal vector is calculated by deadbeat control,and redistributed when it is over modulated.The vector insertion control mode is adopted,changing the action sequence of the vector can reduce the current ripple and improve the dynamic response speed.Finally,system simulation model is built.The simulation results show the proposed method effectively reduces the D-axis and Q-axis current ripple,reduces the network harmonic content,and improves the dynamic response speed and stability of the system.