| 摘要 |
PURPOSE:To realize gradual transfer from electric brake to foot brake by gradually lowering the duty ratio of an inverter upon abnormal temperature rise of a resistor which consumes power to be generated when an AC rotating machine is in generative brake state. CONSTITUTION:Three-phase AC power produced from an AC three-phase rotating machine 3 driven through an engine 1 is inverted through an inverter 6 in order to charge a battery 8 and then an DC/DC converter 9 converts the battery power in order to drive an auxiliary machine(not shown). A series circuit of a switch circuit 15 and a resistor 7 is connected to DC terminals of the inverter 6. Under electric brake mode, the switch circuit 15 is switched in order to consume the generated power through the resistor 7. Temperature of the resistor 7 is then detected 22 and inputted to a resistor control 23. When the temperature exceeds a predetermined level, duty ratio of the switch circuit 15 is lowered gradually through a control circuit 25 thus gradually transferring the electric brake to foot brake. According to the invention, safe and smooth operation is realized. |
