MOTOR DRIVING CIRCUIT, MOTOR DEVICE, AND ELECTRIC VEHICLE

摘要

A motor driving circuit has a supply line connected to a DC power source, an inverter whose input side is connected to the supply line and whose output side is connected to a motor, a power switch inserted in the supply line for switching the supply line between conducting and cut-off states, a voltage detector for detecting a voltage between the direct-current power source and the power switch, and an insulation resistance detector for first detecting, based on a result of detection by the voltage detector with the power switch in the cut-off state, an insulation resistance on the preceding-stage side of the power switch and subsequently detecting, based on a result of detection by the voltage detector with the power switch in the conducting state, an insulation resistance on the succeeding-stage side of the power switch.

主权项

1. A motor driving circuit, comprising:
a supply line connected to a direct-current power source; an inverter of which an input side is connected to the supply line, the inverter converting direct-current electric power inputted from the supply line into alternating-current electric power and outputting the alternating-current electric power to the motor connected to an output side of the inverter; a voltage detector for detecting a voltage between the direct-current power source and the inverter; and an insulation resistance detector for detecting an insulation resistance based on a result of detection by the voltage detector, wherein the inverter has a single-phase arm or multiple-phase arms, the arm or arms comprise, as switching devices connected in series with a positive terminal and a negative terminal of the direct-current power source, upper device and lower devices, the motor is connected between the upper and lower devices, and the insulation resistance detector, wherein
first performs a first detection operation to detect, based on a result of detection by the voltage detector with all the upper devices in an off state, an insulation resistance on a preceding-stage side of the power switch, andsubsequently performs a second detection operation to detect, based on the result of detection by the voltage detector with at least one of the upper devices in an on state, an insulation resistance on a succeeding-stage side of the upper devices.