| 摘要 |
<P>PROBLEM TO BE SOLVED: To accomplish reduction in both the turn-off delay in alternating-current switches and cost of the alternating-current power supply device. <P>SOLUTION: Each of the alternating-current switches 2a, 2b, and 2c connected in series with the power lines 3a, 3b, and 3c of the alternating-current power supply device comprises an inverse-parallel connection circuit of two thyristors and a series circuit of IGBT and a diode connected in inverse-parallel with one of the two thyristors. At normal power supply times, one thyristors S1a, S1b, and S1c and the IGBTs Qa, Qb, and Qc are on-controlled. At overcurrent or IGBT failure times, the other thyristors S2a, S2b, and S2c are on-controlled. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
