一种用于T型三电平逆变器的新型最优开关序列模型预测电压控制OA

A novel optimal switching sequence model predictive voltage control(OSS-MPVC)is proposed for applications requiring constant voltage output.First,it is revealed that the 27 voltage vectors generated by a T-type three-phase three-level inverter can be divided into zero voltage vectors,small voltage vectors,medium voltage vectors,and long voltage vectors.By utilizing small voltage vectors,neutral-point(NP)voltage balancing can be achieved.Based on this principle,48 switching sequences are constructed.To reduce the computational burden,a simplified three-step optimization process is adopted.In Step 1,the candidate sector is identified by exploiting the uniqueness of the medium voltage vectors.In Step 2,the number of the candidate switching sequences is reduced from 8 to 4 based on the voltages of the upper and lower DC link capacitors.In Step 3,the optimal switching sequence is selected from the 4 candidates by minimizing a cost function.Finally,the feasibility of the novel OSS-MPVC strategy is evaluated through experiments in terms of code execution time,steady-state performance,dynamic performance,and NP balancing performance.