Power supply apparatus capable of detecting abnormality in current flowing in drive circuit

• US 20050286181A1
• Filed: 06/07/2005
• Published: 12/29/2005
• Est. Priority Date: 06/25/2004
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ochiai, Kiyoe
• Granted Patent: US 7,372,686 B2
• Time in Patent Office: Days
• US Class Current: 361/23
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: H02H 7/0833 for electric motors with control arrangements
• CPC Class Codes: H02H 7/1227 responsive to abnormalities in the output circuit, e.g. short circuit
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A current detection unit samples motor current at every cycle corresponding to a cycle of the highest processing speed of a CPU. A current integral calculation unit integrates the value of the sampled motor current over a sampling period to calculate and output a current integral to an abnormality determination unit. The abnormality determination unit determines whether the current integral is larger than a threshold. When the abnormality determination unit determines that the current integral is larger than the threshold, it generates a detection signal indicating an abnormality in the motor current and outputs the signal to a relay drive unit and a notification unit. The relay drive unit receives the detection signal to generate a signal for turning off a system relay. The notification unit receives the detection signal to generate and output a signal to display means provided outside a power supply apparatus.

Claims

1. A power supply apparatus comprising:

a power supply;

a drive circuit receiving electric power from said power supply to drive a load circuit; and

an abnormal current detection circuit detecting an abnormality in drive current flowing in said drive circuit,

said abnormal current detection circuit detecting that a current integral of said drive current is larger than a predetermined threshold to determine that said drive current is abnormal.

2. The power supply apparatus according to claim 1, further comprising a switch performing a switching operation to electrically connect/disconnect said power supply and said drive circuit to/from each other, wherein

when said abnormal current detection circuit determines that said drive current is abnormal, said abnormal current detection circuit controls said switching operation to electrically disconnect said power supply and said drive circuit from each other.

3. The power supply apparatus according to claim 1, wherein

said predetermined threshold is lower than a current integral of said drive current that causes said drive circuit to be broken.

4. The power supply apparatus according to claim 1, wherein

said abnormal current detection circuit includes:

current detection means for sampling said drive current at every predetermined calculation cycle;

current integral calculation means for integrating said sampled drive current over a plurality of said predetermined calculation cycles consumed for the sampling to calculate the current integral of said drive current; and

abnormality determination means for determining whether the current integral of said drive current is larger than said predetermined threshold, detecting that the current integral of said drive current is larger than said predetermined threshold and determining that said drive current is abnormal.

5. The power supply apparatus according to claim 4, wherein

said predetermined calculation cycle includes a cycle of a highest operating speed at which said abnormal current detection circuit can operate.

6. The power supply apparatus according to claim 4, wherein

said load circuit includes an AC motor, said abnormal current detection circuit includes mode determination means for determining a control mode of said AC motor,

said mode determination means determines a control mode of said AC motor when said drive current that is out of a normal operating range flows, and

said abnormality determination means adjusts said predetermined threshold to an appropriate threshold that is appropriate for said determined control mode, determines whether the current integral of said drive current is larger than said appropriate threshold, detects that the current integral of said drive current is larger than said appropriate threshold, and determines that said drive current is abnormal.

7. The power supply apparatus according to claim 6, wherein

said mode determination means determines the control mode among control modes with respective carrier frequencies different from each other.

8. The power supply apparatus according to claim 7, wherein

said abnormality determination means adjusts said threshold according to the carrier frequency of said determined control mode.