Developent of high-reliability invertes to realize fault-mode operation under fault condition of power switching devices

本研究项目的目的是开发即使在电源开关设备发生故障时也能维持运行的容错逆变器。结果总结如下：1。采用两相三线连接的故障模式运行的有效性已被实验证实。为了实现故障模式运行时的稳定运行，提出了一种补偿直流中性点电压变化的新方法。阐明了死区时间对不平衡运行的影响。提出了一种补偿死区影响的方法。实验证明了该方法对减小脉动转矩的有效性。在切换到故障模式之前，逆变器必须维持故障电源设备的运行。这可能导致异常大电流。一些实验和模拟结果表明，电流一般不超过正常值的1.6倍。考虑到功率器件的额定余量，这是可以接受的。作为一种检测故障器件的简便方法，本文研究了基于两相电流差计算的故障器件检测方法。仿真结果证实了该方法的基本有效性。

The purpose of this research project is to develop fault-tolerant inverters that can sustain operation even when a fault occurs in-the power switching devices. The results are summarized as follows.1. Effectiveness of the proposed fault-mode operation using two-phase three wire connection has been confirmed experimentally.2. To realize stable operation during fault mode operation, a new method to compensate the variation of the DC neutral point voltage has been proposed.3. The effect of dead time on the unbalanced operation has been clarified. A method to compensate the effect of the dead time has been proposed. The effectiveness of the proposed method on the reduction of the pulsating torque has been demonstrated experimentally.4. Until the connection is change to the fault mode, the inverter must sustain the operation with faulted power devices. This may cause the abnormal large current. It is shown by some experimental and simulated results that the current does not exceed 1.6 times its normal value in general. This is acceptable considering the margin of the rating of the power devices.5. As a simple method to detect the fault devices, a method based on the calculation of the difference of the currents in two phases has been investigated. The basic effectiveness has been confirmed by some results of the simulation.