基于多物理场耦合的并网逆变器容错控制研究

Research on Fault-tolerant Control of Grid-connected Inverter Based on Multi-physics Field Coupling

容错技术是多电平并网逆变器系统可靠运行的关键。针对桥臂故障此处提出了一种三电平混合FC+T型逆变器硬件容错结构,并提出一种应用于混合结构的多目标优化模型预测容错控制方法。该控制方法能够有效减小直流侧中点电压波动,并通过基于多物理场的协同仿真分析方法验证了该容错结构和控制策略的有效性。实验结果表明,重构后的三电平混合FC+T型逆变器在实现低谐波和中性点电位平衡控制的同时,功率损耗和结温也低于故障前的T型桥臂,实现了稳定容错运行。

Fault-tolerance technology is crucial for the reliable operation of multi-level grid-connected inverters.A three-level hybrid FC+T type inverter hardware fault-tolerant structure is proposed specifically designed for bridge arm faults.Additionally,a multi-objective optimization model-based predictive fault-tolerant control method is presented for the hybrid structure.The fluctuations in the midpoint voltage on DC side is effectively reduced by this control method.The effectiveness of the fault-tolerant structure and control strategy is verified through a collaborative simulation analysis based on multiple physical fields.Experimental results demonstrate that the reconstructed three-level hybrid FC+T type inverter achieves stable fault-tolerant operation by simultaneously achieving low harmonics,neutral point potential balance control and lower power loss and junction temperature compared to the pre-fault T-type bridge arm.