Motor drive device

• US 8,045,301 B2
• Filed: 06/28/2007
• Issued: 10/25/2011
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tanaka, Takashi, Tanaka, Nobutaka, Shiba, Kenjiro
• Primary Examiner(s): COLON SANTANA, EDUARDO
• Application Number:
  US12/306,180
• Publication Number:
  US 20090251831A1
• Time in Patent Office: 1,580 Days
• Field of Search: 318/701, 318/706, 318/707, 318/800, 318/430, 318/432, 318/700, 361/23, 361/30, 361/31, 361/1, 363/50, 363/52, 363/53, 363/55, 363/56.01, 363/56.02, 363/56.03, 363/56.04, 180/65.265, 180/65.275, 290/40.C
• US Class Current: 361/23
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 9/18 fed from dc supply lines
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 29/032 Preventing damage to the motor, e.g. setting individual current limits for different drive conditions

Abstract

When an upper arm of U-phase has failed because of short-circuit, lower arms of V-phase and W-phase as the opposite arms are switching-operated. When only the lower arm of V-phase is turned on, a route of motor current passing through an IGBT element from a V-phase coil is formed, and therefore, the motor current returning to the short-circuited phase decreases. Further, by the switching operation of the arm opposite to the short-circuited arm, an AC current is induced in a motor generator. Therefore, it is possible to continuously drive the motor generator while preventing increase in the current passing through the short-circuited phase, without adding a new device structure. This ensures running of the vehicle in the limp mode.

Claims

1. A motor drive device, comprising:

a three-phase AC motor;

a power source capable of supplying DC power to first and second power supply lines;

a power converting device performing power conversion between said first and second power lines and said three-phase AC motor; and

a controller controlling said power converting device such that an output of said three-phase AC motor attains to a target output;

wherein

said three-phase AC motor has coils of the first to third phases electrically connected,

said power converting device includes first to third circuits connected to coils of first to third phases, respectively, of said three-phase AC motor;

each of said first to third circuits has first and second switching elements connected in series a connection node to the coil of respective phase of said three-phase AC motor; and

said controller includes

a short-circuit detecting unit detecting a switching element failed because of short-circuit, from said first to third circuits, and

a motor drive control unit causing, in response to detection of a short-circuited switching element by said short-circuit detecting unit, switching operation of at least one switching element belonging to a circuit different from the circuit to which said short-circuited switching element belongs and arranged, in positional relation, opposite to said short-circuited switching element with said connecting node of each of said first to third circuits interposed, and stopping switching operation of remaining switching element, thereby controlling current flowing through coils of respective phases of said three-phase AC motor.

2. The motor drive device according to claim 1, wherein said motor drive control unit controls, in response to detection of a short-circuit failure of said first switching element of said first circuit, currents flowing through coils of respective phases of said three-phase AC motor by a switching operation of said second switching element of said second and third circuits.

3. The motor drive device according to claim 2, wherein said short-circuit detecting unit detects said short-circuited switching element, based on amplitude of currents flowing through coils of respective phases of said three-phase AC motor.

4. The motor drive device according to claim 3, wherein said short-circuit detecting unit determines that said first switching element of said first circuit is short-circuited, in response to a current flowing through the coil of said first phase of said three-phase AC motor being offset exceeding amplitude of a steady operation of said three-phase AC motor in a direction of a first polarity.

5. The motor drive device according to claim 2, wherein said short-circuit detecting unit detects said short-circuited switching element based on amplitude of an inter-phase voltage of said three-phase AC motor.

6. The motor drive device according to claim 1, wherein said short-circuit detecting unit holds prescribed upper and lower threshold values set in advance based on the amplitude of the inter-phase voltage of said three-phase AC motor in said steady operation state, and detects said short-circuited switching element based on a magnitude relation between the amplitude of the inter-phase voltage of said three-phase AC motor and said upper and lower threshold values.

7. The motor drive device according to claim 2, wherein said short-circuit detecting unit detects said short-circuited switching element, based on a voltage between terminals of said first and second switching elements forming each of said first to third circuits.

8. The motor drive device according to claim 1, wherein said motor drive control unit controls, in response to detection of a short-circuit failure of said first switching element of each of said first and second circuits, currents flowing through coils of respective phases of said three-phase AC motor by a switching operation of said second switching element of said third circuit.

9. The motor drive device according to claim 1, wherein said motor drive control unit controls, in response to detection of a short-circuit failure of said first switching element of said first circuit and of said second switching element of said second circuit, currents flowing through coils of respective phases of said three-phase AC motor by a switching operation of said first and second switching elements of said third circuit.

10. The motor drive device according to claim 1, wherein said three-phase AC motor is coupled to a drive shaft of a vehicle.