| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a cooler. SOLUTION: In a controlling device for electric cars where the DC power of an electric train line 10 is converted to AC by an inverter 17 which is composed of a semiconductor element 18 being switched at a specific switching frequency for driving an AC electric motor 19. Regenerative power is sent to the electric train line 10 via the AC electric motor 19 when brakes are applied. A controlling means 21 is provided for reducing the switching frequency of a semiconductor element 18 when the temperature change rate of the semiconductor element 18 to time exceeds a setting value. |
