Interlock device

Abstract

To lock a cover when a voltage of a circuit installed in a power control unit does not sufficiently decrease.SOLUTION: An interlock device for locking a cover for opening and closing a power control unit that is provided in an electric vehicle includes: a coil connected in parallel to a capacitor installed in the power control unit and generating electromagnetic force with electrical charge accumulated in the capacitor; and a lock mechanism for locking the cover while the cover is closed so that the cover cannot be open from the outside when the coil generates electromagnetic force.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an interlock device. [Background technology]

[0002] In electric vehicles such as hybrid vehicles or electric vehicles, high-voltage circuits such as inverters are installed in a power control unit, which is housed in a closed space isolated from the passenger compartment and luggage compartment. Electric vehicles have measures in place to ensure the safety of workers who perform maintenance or inspections of high-voltage equipment. For example, in electric vehicles, if the cover of the housing that houses the high-voltage equipment is opened, the power supply to the high-voltage equipment is forcibly stopped.

[0003] Furthermore, high-voltage circuits such as inverters generally include capacitors, which continue to store electric charge even after the power supply is stopped. For this reason, high-voltage circuits provided in electric vehicles discharge the electric charge stored in the capacitor after the power supply is stopped by using a passive discharge resistor connected in parallel to the capacitor and an active discharge circuit controlled by an ECU (Electronic Control Unit) or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-014577 [Patent Document 2] Japanese Patent Publication No. 2022-181191 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it takes a certain amount of time for the passive discharge resistor and active discharge circuit to discharge the electric charge. Therefore, even if the electric charge is discharged by the passive discharge resistor and active discharge circuit, the electric charge still accumulates in the capacitor immediately after the power control unit cover is opened. For this reason, after opening the cover, workers must perform a voltage test to confirm safety before performing maintenance or inspection of the high-voltage circuit inside the power control unit.

[0006] Furthermore, since a high voltage is applied to a passive discharge resistor, it is made of a high-voltage-resistant material. Therefore, in order to meet the voltage-resistant specifications, a passive discharge resistor must be configured with many components connected in series, resulting in a large size. Furthermore, if a passive discharge resistor is miniaturized using a high-voltage-resistant material, it becomes expensive.

[0007] The present invention has been made in consideration of the above, and aims to provide an interlock device that can lock a cover when the voltage of a circuit provided inside a power control unit has not dropped sufficiently. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the interlock device of the present invention is an interlock device that locks a cover that opens and closes a power control unit provided in an electric vehicle, and includes a coil that is connected in parallel to a capacitor provided inside the power control unit and generates an electromagnetic force by the charge stored in the capacitor, and a locking mechanism that, when the electromagnetic force is generated from the coil, locks the cover in a closed state so that it cannot be opened from the outside. [Effects of the Invention]

[0009] According to the present invention, the cover can be locked when the voltage of the circuit provided inside the power control unit has not dropped sufficiently. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of an electric vehicle. [Figure 2] FIG. 2 is a diagram showing the configuration of the power control unit when the cover is locked. [Figure 3] FIG. 3 is a diagram showing the configuration of the power control unit when the cover is unlocked. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings as appropriate. However, more detailed description than necessary may be omitted. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0012] FIG. 1 is a diagram showing the configuration of an electric vehicle 10 according to an embodiment.

[0013] The electric vehicle 10 includes a first motor generator 20, a second motor generator 22, a secondary battery 24, an auxiliary battery 26, an ECU 28, and a power control unit 30.

[0014] The first motor generator 20 receives three-phase driving power from the power control unit 30 and rotates a rotating shaft. The rotating shaft of the first motor generator 20 is connected to an axle via a transmission, a differential, etc. This allows the first motor generator 20 to rotate the wheels and run the electric vehicle 10.

[0015] The second motor generator 22 receives three-phase driving power from the power control unit 30 and rotates a rotating shaft. The rotating shaft of the second motor generator 22 is connected to an axle different from the axle to which the first motor generator 20 is connected via a transmission, a differential, etc. This allows the second motor generator 22 to rotate the wheels and run the electric vehicle 10.

[0016] The secondary battery 24 is, for example, a lithium ion battery, and is supplied with power from a charging station or the like. The secondary battery 24 generates a DC voltage of, for example, several hundred volts. The secondary battery 24 supplies power to the power control unit 30.

[0017] The auxiliary battery 26 is a rechargeable battery such as a lead-acid battery. The auxiliary battery 26 is charged by receiving power from the secondary battery 24 via the power control unit 30. The auxiliary battery 26 generates a DC voltage of, for example, about 10 volts. The auxiliary battery 26 supplies power to electrical devices in the electric vehicle 10, such as the ECU 28, power windows, headlights, and air conditioner.

[0018] The ECU 28 is a semiconductor circuit or module configured with a processor or a dedicated circuit, and controls various devices provided in the electric vehicle 10.

[0019] The power control unit 30 houses a high-voltage circuit that operates at a high voltage for propelling the electric vehicle 10 in a closed space isolated from the passenger compartment and luggage compartment. The power control unit 30 receives power from the secondary battery 24 and charges the auxiliary battery 26. The power control unit 30 also outputs three-phase drive power for driving the first motor generator 20 to rotate and three-phase drive power for driving the second motor generator 22 to rotate.

[0020] The power control unit 30 is provided with a cover 32 that allows an operator to perform maintenance or inspection of the devices, circuits, etc. housed inside. The cover 32 is normally closed, isolating the devices, circuits, etc. housed inside from the outside. When an operator performs maintenance or inspection of the devices, circuits, etc. housed inside the power control unit 30, the operator opens the cover 32.

[0021] When an operator opens the cover 32, the ECU 28 forcibly stops the voltage supply from the secondary battery 24 to the power control unit 30. Furthermore, even after the operator opens the cover 32 and stops the power supply, the power control unit 30 locks the cover 32 from the inside until the internal voltage drops below a predetermined voltage. This allows the power control unit 30 to prevent an operator from performing maintenance or inspection of the devices and circuits housed inside if the internal voltage is higher than the predetermined voltage. Then, when the internal voltage drops below a safe voltage, the power control unit 30 releases the lock and allows the cover 32 to be opened.

[0022] Figures 2 and 3 are diagrams showing the internal configuration of the power control unit 30. More specifically, Figure 2 is a diagram showing the configuration of the power control unit 30 when the cover 32 is locked. Figure 3 is a diagram showing the configuration of the power control unit 30 when the cover 32 is unlocked.

[0023] The power control unit 30 includes a housing 40. A cover 32 can be attached and detached to the housing 40. When the cover 32 is attached, the housing 40 isolates the devices, circuits, etc. housed inside from the outside. When the cover 32 is opened and removed, the housing 40 has a partial opening. A worker can perform maintenance and inspection of the devices, circuits, etc. housed inside the power control unit 30 through the opening in the housing 40 that appears when the cover 32 is removed.

[0024] The power control unit 30 has a DC-DC converter 42, an input section 44, a boost section 46, a first inverter 48, a second inverter 50, an MGECU (Motor Generator Electronic Control Unit) 52, a capacitor 54, and an interlock device 56 inside a housing 40.

[0025] Power control unit 30 also includes a positive input terminal 66 , a reference voltage terminal 68 , and a high voltage output terminal 70 .

[0026] The positive input terminal 66 is connected to the positive voltage terminal of the secondary battery 24. The reference voltage terminal 68 is connected to the negative voltage terminal of the secondary battery 24.

[0027] The DC-DC converter 42 receives DC power from the secondary battery 24 via the positive input terminal 66 and the reference voltage terminal 68. The DC-DC converter 42 steps down the DC voltage generated by the secondary battery 24 to a DC voltage to be applied to the auxiliary battery 26, and supplies the DC voltage to the auxiliary battery 26. The DC-DC converter 42 functions as a charging device that transfers power from the secondary battery 24 to the auxiliary battery 26.

[0028] The input section 44 is provided between the positive input terminal 66 and the reference voltage terminal 68. The input section 44 removes noise output in the reverse direction from the power control unit 30 to the secondary battery 24 side.

[0029] Boost unit 46 receives DC power from secondary battery 24 via positive input terminal 66 and reference voltage terminal 68. Boost unit 46 boosts the DC voltage generated by secondary battery 24 to a motor drive voltage of a predetermined voltage value and outputs it from between high voltage output terminal 70 and reference voltage terminal 68. Boost unit 46 generates a DC motor drive voltage from high voltage output terminal 70 for driving first motor generator 20 and second motor generator 22.

[0030] First inverter 48 generates a three-phase drive voltage by switching the motor drive voltage generated between reference voltage terminal 68 and high voltage output terminal 70. First inverter 48 provides the generated three-phase drive voltage to first motor generator 20.

[0031] The second inverter 50 generates a three-phase drive voltage by switching the motor drive voltage generated between the reference voltage terminal 68 and the high voltage output terminal 70. The second inverter 50 supplies the generated three-phase drive voltage to the second motor generator 22.

[0032] The MGECU 52 is a semiconductor circuit or module configured with a processor or a dedicated circuit. The MGECU 52 is controlled by the ECU 28 and controls the switching of the first inverter 48 and the second inverter 50. In this way, the MGECU 52 controls the torque of the first motor generator 20 and the second motor generator 22. The MGECU 52 also controls the switching of the voltage step-up unit 46.

[0033] Capacitor 54 is connected between high voltage output terminal 70 and reference voltage terminal 68. The motor drive voltage output from booster 46 between high voltage output terminal 70 and reference voltage terminal 68 is applied to capacitor 54. Capacitor 54 stores a charge corresponding to the motor drive voltage. Such capacitor 54 can provide a stabilized motor drive voltage to first inverter 48 and second inverter 50.

[0034] The interlock device 56 includes a first terminal 76 , a second terminal 78 , a coil 80 , a movable member 82 , a support member 84 , and a resilient member 86 .

[0035] The first terminal 76 is connected to one terminal of the capacitor 54. In this example, the first terminal 76 is connected to the terminal of the capacitor 54 that is connected to the reference voltage terminal 68.

[0036] The second terminal 78 is connected to the terminal of the capacitor 54 that is not connected to the first terminal 76. In this example, the second terminal 78 is connected to the terminal of the capacitor 54 that is connected to the high-voltage output terminal 70.

[0037] One terminal of the coil 80 is connected to the first terminal 76, and the other terminal is connected to the second terminal 78. That is, the coil 80 is electrically connected in parallel to the capacitor 54. The coil 80 connected in this manner generates an electromagnetic force due to the charge stored in the capacitor 54. The coil 80 is provided at a fixed position relative to the housing 40 of the power control unit 30. For example, the coil 80 may be wound around a shaft fixed to the housing 40 of the power control unit 30 or the outer frame of the interlock device 56, for example.

[0038] The movable member 82 is provided inside the housing 40 of the power control unit 30 so as to be movable relative to the housing 40. In this example, the movable member 82 is, for example, a long, thin, rod-shaped member. The movable member 82 is provided so as to be movable back and forth such that a first tip region 82a moves toward and away from an end 80a of the coil 80 opposite the first terminal 76 and the second terminal 78. In this example, the movable member 82 is rotatable around a predetermined position in the longitudinal direction of the rod-shaped member.

[0039] The support member 84 is provided at a fixed position relative to the housing 40 of the power control unit 30. The support member 84 holds the movable member 82 so that it can move back and forth in a predetermined direction so that one first tip region 82a of the movable member 82 approaches and moves away from the end 80a of the coil 80. In this example, the support member 84 holds the movable member 82 rotatably around a predetermined position 82c in the longitudinal direction of the rod-shaped movable member 82 as the rotation axis.

[0040] The elastic member 86 applies a force to the movable member 82 in a direction that moves the first tip region 82a of the movable member 82 away from the end 80a of the coil 80. In this example, the elastic member 86 is a return spring. One end of the elastic member 86, which is a return spring, is fixed to the housing 40 of the power control unit 30 or the outer frame of the interlock device 56, and the other end is connected to the second tip region 82b of the rod-shaped movable member 82, which is opposite to the first tip region 82a. When no force is applied to the movable member 82 from any source other than the elastic member 86, the elastic member 86, which is a return spring, returns the position of the first tip region 82a to a predetermined position away from the end 80a of the coil 80.

[0041] Here, at least the first tip region 82a of the movable member 82 is made of metal. The entire movable member 82 may be made of metal. Therefore, when the coil 80 generates an electromagnetic force due to the charge stored in the capacitor 54, the first tip region 82a of the movable member 82 moves toward the end 80a of the coil 80 due to the electromagnetic force generated by the coil 80, as shown in FIG. 2. On the other hand, when the capacitor 54 does not store a charge and the coil 80 does not generate an electromagnetic force, the first tip region 82a of the movable member 82 moves away from the end 80a of the coil 80 due to the restoring force applied by the elastic member 86, as shown in FIG.

[0042] The cover 32 is also provided with an engagement portion 88. The engagement portion 88 is provided at a position that protrudes into the housing 40 when the cover 32 is attached to the housing 40.

[0043] Furthermore, a locking mechanism 90 is provided near the first tip region 82a of the movable member 82. For example, the locking mechanism 90 is provided at the end portion of the rod-shaped member on the first tip region 82a side.

[0044] The locking mechanism 90 moves to the first position when the first tip region 82a of the movable member 82 comes closest to the end 80a of the coil 80. In the first position, the locking mechanism 90 engages with an engaging portion 88 provided on the cover 32, and locks the cover 32 in the closed state so that it cannot be opened from the outside.

[0045] The locking mechanism 90 moves to the second position when the first tip region 82a of the movable member 82 moves away from the end 80a of the coil 80. In the second position, the locking mechanism 90 disengages from the engaging portion 88 provided on the cover 32, unlocking the cover 32 and allowing the cover 32 to be opened from the outside.

[0046] In this way, the locking mechanism 90 is provided on the movable member 82 so as to be movable back and forth between a first position in which the cover 32 is locked so that it cannot be opened from the outside when the cover 32 is closed, and a second position in which the cover 32 is unlocked so that it can be opened from the outside.

[0047] When an electric charge is accumulated in capacitor 54 and coil 80 is generating electromagnetic force, first tip region 82a of movable member 82 approaches end 80a of coil 80, moving locking mechanism 90 to the first position. Therefore, when an electric charge is accumulated in capacitor 54 and coil 80 is generating electromagnetic force, locking mechanism 90 locks cover 32 in a closed state so that cover 32 cannot be opened from the outside.

[0048] Furthermore, when no charge is stored in capacitor 54 and coil 80 is not generating electromagnetic force, first tip region 82a of movable member 82 moves away from end 80a of coil 80, moving locking mechanism 90 to the second position. Therefore, when no charge is stored in capacitor 54 and coil 80 is not generating electromagnetic force, locking mechanism 90 unlocks cover 32, allowing cover 32 to be opened from the outside.

[0049] The elastic member 86 is adjusted to have a spring force such that the first tip region 82a separates from the end 80a of the coil 80 when the voltage generated by the capacitor 54 is lower than a predetermined voltage that is lower than a safe voltage determined, for example, by the specifications of the power control unit 30, and the first tip region 82a does not separate from the end 80a of the coil 80 when the voltage is equal to or higher than the predetermined voltage. Therefore, when the voltage generated by the capacitor 54 is lower than the predetermined voltage, the elastic member 86 applies a force to the movable member 82 that moves the locking mechanism 90 from the first position to the second position. In other words, when the voltage generated by the capacitor 54 is higher than the predetermined voltage, the elastic member 86 applies a force to the movable member 82 sufficient to keep the locking mechanism 90 in the first position. The spring force of the elastic member 86 is adjusted at the time of shipment or maintenance so as to apply such a force to the movable member 82.

[0050] As described above, the interlock device 56 of the power control unit 30 locks the cover 32 from the inside until the voltage of the capacitor 54 falls below a predetermined voltage, even after an operator opens the cover 32 and stops the power supply to the power control unit 30. In this way, the interlock device 56 can prevent an operator from performing maintenance or inspection of the equipment and circuits housed inside the power control unit 30 if the voltage of the capacitor 54 is higher than the predetermined voltage. Then, when the internal voltage falls below a safe voltage, the power control unit 30 releases the lock and allows the cover 32 to be opened.

[0051] Such interlock device 56 can lock the cover 32 in a closed state even if an operator attempts to open the cover 32, as long as the voltage of the high-voltage circuit provided inside the power control unit 30 has not dropped sufficiently. Then, the interlock device 56 can unlock the cover 32 after the voltage of the high-voltage circuit provided inside the power control unit 30 has dropped sufficiently. Such interlock device 56 can further improve the safety of operators performing maintenance or inspection of the high-voltage circuit inside the power control unit 30.

[0052] In the power control unit 30 having such an interlock device 56, the coil 80 is connected in parallel to the capacitor 54. Therefore, in the power control unit 30, the coil 80 acts as a passive discharge resistor, consuming the charge stored in the capacitor 54 and discharging the capacitor 54. Therefore, the power control unit 30 does not need to be provided with a passive discharge resistor, which is large or expensive, and can be made smaller and less expensive.

[0053] In this example, the coil 80 is provided in parallel with the capacitor 54 connected between the high voltage output terminal 70 and the reference voltage terminal 68. However, instead of the capacitor 54, the coil 80 may be connected in parallel with a circuit or element having another capacitance component that generates a high voltage within the power control unit 30.

[0054] Although the embodiments of the present invention have been described above, these embodiments have been presented as examples, and various modifications can be made to the embodiments, and are not intended to limit the scope of the invention. [Explanation of symbols]

[0055] 10 Electric vehicle, 20 First motor generator, 22 Second motor generator, 24 Second battery, 26 Auxiliary battery, 28 ECU, 30 Power control unit, 32 Cover, 40 Housing, 42 DC-DC converter, 44 Input section, 46 Boost section, 48 First inverter, 50 Second inverter, 52 MGECU, 54 Capacitor, 56 Interlock device, 76 First terminal, 78 Second terminal, 80 Coil, 82 Movable member, 84 Support member, 86 Elastic member, 88 Engagement section, 90 Locking mechanism

Claims

1. An interlock device that locks a cover that opens and closes a power control unit provided in an electric vehicle, a coil connected in parallel to a capacitor provided inside the power control unit, the coil generating an electromagnetic force by electric charges accumulated in the capacitor; a locking mechanism that locks the cover in a closed state so that the cover cannot be opened from the outside when the electromagnetic force is generated from the coil; An interlock device comprising:

2. a movable member provided with the locking mechanism; the locking mechanism is provided on the movable member so as to be reciprocable between a first position at which the cover is locked so that it cannot be opened from the outside when the cover is closed, and a second position at which the cover is unlocked so that it can be opened from the outside, The movable member moves the locking mechanism to the first position when the electromagnetic force is generated. The interlock device according to claim 1 .

3. The lock mechanism further includes an elastic member that applies a force to the movable member to move the lock mechanism from the first position to the second position when the voltage generated by the capacitor is smaller than a predetermined voltage. The interlock device according to claim 2 .

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