| 摘要 |
PURPOSE:To enhance the reliability of a PWM inverter by connecting in series two controllable power sources via coupling reactors and providing terminals connecting both terminals of series circuit and 1-phase output terminals of neutral points of the reactors in number corresponding to the number of phases. CONSTITUTION:DC converters SPC1-SPC6 are connected in series through coupling reactors L14, L36, L52 for two, terminals A connected at both terminals of the respective series circuits and the neutral points B of the reactors are used as the output terminal of one phase, and the output terminals of the respective phases are connected to 3-phase motor M of six leads. When the choppers Ch1, Ch2 of the converters of the respective phases become impossible to be controlled in ON state during its operation, a current circulating the annular circuits of the respective phases increases, allowing the defect current to be detected by a current detector CT to operate a high speed protecting breaker HS, thereby breaking the defect current to prevent the burnout accident. |
