| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor drive system presenting equal effects to monitoring at two positions by monitoring a discharge current from a short-circuit detection capacitor of small capacity which is connected to a DC link capacitor in a three-level inverter in parallel, with a current sensor at one position in place of monitoring a discharge current from the DC link capacitor with current sensors at two positions in the case of DC short-circuiting, and a DC short-circuit detection device for the motor drive system.SOLUTION: In a DC short-circuit detection device 20, between P and C, a first charging circuit is provided which includes a connection point P1 where a short-circuit detection capacitor CP2 and a forward diode D1 are connected in series from a P pole side. In C and B, a second charging circuit is provided which includes a connection point P2 where a forward diode D2 and a short-circuit detection capacitor CN2 are connected in series from a C pole side. Further, between the second connection point and the first connection point, a discharging circuit is provided in which a third diode and a current sensor CT are connected in series from the side of the second connection point.SELECTED DRAWING: Figure 2 |
