| 主权项 |
1. A power supply current monitoring apparatus for a load drive apparatus, the load drive apparatus including a battery and two systems configured to work in cooperation with each other to drive a load, each system including a drive circuit connected in parallel with the battery, an input capacitor connected between the battery and the drive circuit, and a power supply relay connected between the drive circuit and a power blanching point, at which power of the battery is divided between the systems, to open and close a power supply path from the battery to the drive circuit, the power supply current monitoring apparatus configured to monitor a magnitude of a power supply current flowing through the power supply relay toward the drive circuit in each system, the power supply current monitoring apparatus comprising:
a failure determinator that determines whether a short-circuit failure occurs based on a voltage across a current detector through which the power supply currents flows, the short-circuit failure defined as a failure occurring when a high potential side and a low potential side of the drive circuit is short-circuited, and a power supply relay controller that opens and closes the power supply relay, wherein when the failure determinator detects the power supply current exceeding a predetermined first threshold once in one of the systems, a repetitive monitoring process is performed, the one of the systems being defined as a temporary abnormal system having a possibility that the short-circuit failure occurs therein, and the other of the systems being defined as a normal system having no possibility that the short-circuit failure occurs therein, the repetitive monitoring process determines that the short-circuit failure actually occurs in the temporary abnormal system when a predetermined condition is satisfied by repeating a monitoring cycle a predetermined number of times, the monitoring cycle turns OFF the power supply relay of the temporary abnormal system and then monitors the magnitude of the power supply current when a predetermined cycle time elapses from a start time by turning ON the power supply relay of the temporary abnormal system, the start time being a time at which the power supply current exceeds the first threshold, the repetitive monitoring process includes a mask procedure to stop monitoring the magnitude of the power supply current in the normal system, and the mask procedure is performed at least for a predetermined time period after the power supply relay of the temporary abnormal system is turned OFF in each the monitoring cycle. |
