中文摘要：

为了进一步提高级联H桥型逆变器在开关器件故障时的容错能力，在详细分析了常见的短路和断路等故障对系统输出影响的基础上，提出了仅隔离故障开关管的思路。针对具体故障类型，对同一桥臂的另外一个开关管做出相应的处理，即常开或常闭，而另外一个未发生故障的桥臂仍然继续工作，此时单元的输出是两电平。与目前所采用的传统故障处理方法相比，在大多数故障形式下，该方法均能够提升输出合成电压的幅值，从而减少故障对系统的影响，提高级联H桥逆变器系统的可靠性。文中以六单元级联H桥系统为例进行分析，系统故障前后的仿真和实验结果表明所提出的方案是正确和有效的。

英文摘要：

To increase the fault tolerance for cascaded H-bridge multilevel inverter（CHMI）, a novel control method is presented for operating the inverter when one or more switch devices are damaged. To control the inverter with faulty switches, only the faulty switch is bypassed, the control signals for other switches in the faulty cell are modified according to the fault type. The power cell with faulty switch can still output a two level voltage. The influence of various faults on space vectors is analyzed and the maximum achievable output voltage of the inverter with faulty switch devices is calculated. Compared with existing control methods, this method generates higher voltage space vector magnitudes and reduces the influence of switch problems on motor operation in most fault modes, while maintaining a balanced line to line voltage, the reliability of the system is then enhanced. The simulated results agree with the theoretical analysis.