张斌 许伟奇 戴乾军

摘 要关键词：三相八开关容错逆变器;有限控制集模型预测控制;扩张状态观测器;永磁同步电机;开关频率

DOI：10.15938/j.emc.2019.06.000

中图分类号文献标志码：A 文章编号：1007 -449X（2019）06 -0000 -00

Abstract：The operation mode of driving system under fault conditions is studied aiming at the single bridge arm fault and unbalanced bus voltage dividing of PNC threelevel inverter， a drive control strategy is proposed for three phases eightswitch faulttolerant inverter （TPESFTI） with current feedback characteristics， and its topology and output voltage model are constructed.Combined model predictive control theory with extended state observer （ESO） technology， a finite control set model predictive control is proposed for PMSM systems Driven by three phase eightswitch faulttolerant inverter. Considering the influence of system parameter changes on the back EMF， an observer is designed by extended state observer（ESO） technology to realize the realtime estimation of the back EMF. At the same time， the nonlinear constraint term of the objective function in FCSMPC is used to reduce the switching frequency of the inverter. The simulation results show that the control strategy can ensure the reliable and stable operation of TPESFTI drive PMSM system， which can not only effectively suppress the adverse effect resulting from the unbalance of DC link capacitor voltages on the system and reduce switching loss， but also with good dynamic performance as well as strong load resistance and robustness .

Keywords： threephase eightswitch faulttolerant inverter; finite control set model predictive control; extended state observe; permanent magnet synchronous; switch frequency

0 引 言

1981年Naba A等[1]学者对三电平逆变器（neutral point clamped， NPC）进行深入地研究分析，并获得了其拓扑结构和空间电压矢量。与常规三相两电平相比，三相NPC型三电平逆变器具备优良的谐波频谱，较小的功率管承电压力和开关损耗以及高效性等显著优势;因此，在交流电机驱动领域应用最为广泛[2-11]。由于NPC型三电平逆变器结构需要更多的功率管器件，从而会导致其可靠性降低，一旦某桥臂故障（即短路和断路）时将会使驱动系统停止运行，甚至会影响其他系统的安全运行，并且造成不可估量的经济损失[12]。在某些交流传动控制领域中对驱动系统的可靠性要求较高，即使逆变器发生故障时，系统仍能持续稳定运行。因此，为了提高三电平逆变器驱动系统的可靠性，将对其容错控制技术的研究具有更重要意义。

近些年来，海内外学者对三电平逆变器的容错控制进行深入研究，目前，NPC型三电平逆变器的容错控制技术成为热门的研究课题[13-21]。NPC型三电平逆变器的任何一桥臂发生短路或断路时，最常用的两种容错控制拓扑结构为：“三桥臂”和“四桥臂”[20]。文献[13-18]采用的是三橋臂容错拓扑结构的方法;其实质是逆变器的某一桥臂故障时，在不需要增添冗余主桥臂基础上，将连接故障桥臂相和直流母线两电容中点，即为三相八开关逆变器（threephases eightswitch Inverter，TPESI）的容错控制策略。……