Based on state - space method to study the inverter fed permanent magnet synchronous machine , the sorts of the switch fault are given and the causes for the faults are analyzed . it investigates the currents and torque of the drive system fed by six - step inverter and pwm inverter under the different fault condition , and the valuable results are got 2 在利用状态空间法深入分析永磁同步电动机变频调速系统稳态特性的基础上，分析了逆变器开关元件发生故障的类型及其原因，仿真分析了六阶梯波逆变器、 pwm逆变器各种故障状态下的系统动态特性，得出了一些有价值的结论。
The feasibility of the scheme as well as the digital control system is validated on a small power prototype . furthermore , the method of improving the quality of output voltage and increasing the utilization ratio of the dc input voltage through adding channels is analyzed and experimentally verified . at last , optimal design methodology of the multi - channel pwm staircase inverter is shown 在研究二通道单边脉宽调制阶梯波合成逆变器的基础上，本文分析了通过增加通道数提高输出电压波形质量和输入直流电压利用率的方法，给出了多通道脉宽调制阶梯波合成逆变器的优化设计思想。
Three - level converter is a novel technology that is produced and developed in 1980 ' s . three - level ladder output voltage is accomplished by dc - side division voltage and different switch combination , and the capacity of converter system and endure voltage are efficiently improved , and the output voltage harmonics and switch loss are reduced 三电平换流器是20世纪80年代产生并发展起来的一种新兴变流技术，它通过对直流侧的分压和开关动作的不同组合，实现三电平阶梯波输出电压，能有效地提高换流器系统地容量和耐压，减少输出电压谐波和开关损耗。
