JP4126936B2 - Relay control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a relay control device. In particular, the present invention controls a relay that is connected to a positive electrode and a negative electrode of a battery that is a power source of a motor, has two fixed contacts and a movable contact, and a permanent magnet is disposed in the vicinity of the fixed contact and the movable contact. The present invention relates to a control device.
[0002]
[Prior art]
Conventionally, an electric vehicle that travels by driving a motor is known. A system main relay (hereinafter referred to as SMR), which is a control relay for controlling power supply from the battery, is provided between the motor and the battery on the positive side and the negative side of the battery. ing.
[0003]
FIG. 3 is a circuit configuration diagram of a motor power supply device 12 conventionally used in an electric vehicle. The battery 20 is an assembled battery composed of a large number of battery cells, and has an output voltage of about 300V. The positive electrode of the battery 20 is connected to one end of the inverter 40 via the SMR 30. Further, the negative electrode of the battery 20 is connected to the other end of the inverter 40 via the SMR 32. A three-phase AC motor 50 is connected to the inverter 40 as a load. Therefore, when the SMR 30 and the SMR 32 are turned on, electric power is supplied to the inverter 40, and three-phase alternating current is generated by switching control of the inverter 40. The three-phase AC motor 50 is driven by the three-phase AC, and the vehicle travels.
[0004]
Specifically, when the driver gets into the vehicle and performs a key operation to start driving, the power control device (not shown) controls on / off of the SMR, and the positive and negative electrodes of the battery 20 are connected to the load side. Connected to the circuit. When the driver performs a key operation for stopping the operation, the power supply control device controls on / off of the SMR, and the positive and negative electrodes of the battery 20 are disconnected from the load side circuit.
[0005]
With respect to SMR, a configuration is known in which a permanent magnet is disposed in the vicinity of a fixed contact and a movable contact in order to eliminate an arc generated when the movable contact is separated from the fixed contact based on Fleming's left-hand rule.
[0006]
FIG. 4 is a diagram showing a configuration of the SMR in which permanent magnets are arranged in the vicinity of the fixed contact and the movable contact. The fixed contacts 112 and 122 include fixed contacts 110 and 120, respectively. The plunger 140 reciprocates by exciting or de-energizing an electromagnet (not shown). The plunger 140 is connected to a plate-shaped movable contact 130 having conductivity. The movable contact 130 includes movable contacts 114 and 124 corresponding to the fixed contacts 110 and 120, respectively. By controlling the reciprocating motion of the plunger 140, on / off of the fixed contact and the movable contact is controlled.
[0007]
The permanent magnets 150 and 160 are arranged so as to face each other with the fixed contacts 110 and 120 and the movable contacts 114 and 124 interposed therebetween. When the S pole and N pole of the permanent magnets 150 and 160 are taken as shown in FIG. 4 and the direction of the current is taken from the fixed contact 110 to the movable contact 114, the gap between the fixed contact 110 and the movable contact 114 is interrupted when the current is interrupted. And the arc 180 generated between the fixed contact 120 and the movable contact 124 are stretched away from each other by the action of the magnetic field generated from the permanent magnet.
[0008]
[Problems to be solved by the invention]
By the way, the electric vehicle travels by controlling the output torque of the motor according to the amount of depression of the accelerator (power running state). On the other hand, during deceleration, regenerative braking is used in addition to normal mechanical braking. In this case, the motor acts as a generator and generates negative torque (regenerative torque) (regenerative state). The electric power generated by the motor is used for charging the battery. That is, in the power running state and the regenerative state, the direction of the current flowing in the motor power supply circuit is reversed. Therefore, for example, if the direction of the current of the SMR in FIG. 4 is the power running state, the current is in the opposite direction in the regenerative state. For this reason, in the regenerative state, the arc 170 and the arc 180 are stretched in a direction approaching each other, and as a result of the arcs approaching each other, the fixed contact 110 and the fixed contact 120 may be short-circuited. It had been.
[0009]
Then, an object of this invention is to provide the relay control apparatus which can solve said subject. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.
[0010]
[Means for Solving the Problems]
That is, the present invention includes two fixed contacts each having a fixed contact;
A movable contact having two movable contacts that are separable in a direction perpendicular to the arrangement direction of the two fixed contacts and arranged in a direction parallel to the arrangement direction of the fixed contacts ;
A drive unit for driving the movable contact;
Permanent magnets that are arranged to face each other with the fixed contact and the movable contact in between, and form a magnetic field in a direction perpendicular to a plane including the arrangement direction of the two fixed contacts and the arrangement direction of the two movable contacts. When,
Have
A relay control device for controlling a first control relay and a second control relay, which are connected to a positive electrode and a negative electrode of a battery, respectively, and open and close a connection between the battery and a motor driven by electric power supplied from the battery,
When the motor is in a power running state and a forward current that is the direction of the current in the power running state flows, the fixed state when the forward current flows between the first control relay and the second control relay. An arc generated between the fixed contact and the movable contact if a forward current flows through one control relay in which an arc generated between the contact and the movable contact extends in a direction away from each other by the action of the magnetic field. Opened before the other control relay that will be stretched in the direction approaching each other by the action of the magnetic field ,
When the motor is in a regenerative state and a reverse current, which is the direction of the current in the regenerative state, flows, the fixed state when the reverse current flows between the first control relay and the second control relay. An arc generated between the fixed contact and the movable contact if a reverse current flows through the other control relay in which an arc generated between the contact and the movable contact extends in a direction away from each other by the action of the magnetic field. Are opened before the one control relay that is stretched in the direction approaching each other by the action of the magnetic field .
[0011]
The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are the solution of the invention. It is not always essential to the means.
[0013]
FIG. 1 is a schematic configuration diagram of a motor power supply device 10 to which the relay control device 70 according to the embodiment is applied. Note that the same portions as those in the conventional example of FIG.
[0014]
The SMR 30 and the SMR 32 have the same configuration as the SMR of FIG. 4, the fixed contact 112 of the SMR 30 is connected to the positive side of the battery, and the fixed contact 122 of the SMR 32 is connected to the negative side of the battery. Here, regarding the direction of the current, the direction of the current in the power running state is referred to as a forward current, and the direction of the current in the regenerative state is referred to as a reverse current.
[0015]
An inverter control device 60 is connected to the inverter 40, and the inverter control device 60 controls the operation of the inverter 40. A position sensor 52 that detects the rotor position is attached to the three-phase AC motor 50. The position sensor 52 is composed of a hall element or the like. A current sensor 54 is attached to the current path from the inverter 40 to the three-phase AC motor 50. The detected values of the position sensor 52 and the current sensor 54 are supplied to the inverter control device 60.
[0016]
The inverter control device 60 is supplied with signals regarding the operation status of the accelerator and brake, and the inverter control device 60 determines the output torque command of the three-phase AC motor 50 from these signals. Then, the inverter 40 is controlled to control the drive current to the three-phase AC motor 50 so that the output torque of the three-phase AC motor 50 matches the determined output torque command. The phase of the motor drive current is controlled according to the detection value of the position sensor 52, and the motor drive current is feedback-controlled by the detection value of the current sensor 54. Inverter control device 60 transmits to relay control device 70 a signal indicating whether three-phase AC motor 50 is in a power running state or a regenerative state.
[0017]
When the forward operation of the SMR 30 or 32 is flowing according to the signal transmitted from the inverter control device 60 when the driver performs a key operation for stopping operation, the relay control device 70 The SMR 30 is turned off before the SMR 32, and when a reverse current is flowing, the SMR 32 is turned off before the SMR 30.
[0018]
FIG. 2 is a flowchart showing on / off control of the SRM by the relay control device 70. First, operation stop is commanded by a key operation of the driver (S10). Based on the signal transmitted from the inverter control device 60, it is determined whether or not the three-phase AC motor 50 is in a power running state (S20), and the three-phase AC motor 50 is in a power running state and forward current is flowing. In this case, the SMR 30 in a state where the arcs are separated from each other by the permanent magnet is turned off before the SMR 32 (S30), and the SMR 32 is turned off after a predetermined time (S40).
[0019]
On the other hand, when the three-phase AC motor 50 is not in the power running state (in the regenerative state), the SMR 32 arcs are separated from each other, contrary to the power running state. Therefore, when the motor is in a regenerative state and a reverse current is flowing, the SMR 32 is turned off before the SMR 30 (S50), and the SMR 30 is turned off after a predetermined time has elapsed (S60). To do.
[0020]
In this way, depending on whether the motor is in a power running state or a regenerative state, the SMR in which the arcs are separated from each other is turned off before the other SMR, so that the current between the contacts can be reduced. Therefore, it is possible to avoid the short circuit of the arc generated in the SMR, thereby improving the SMR blocking ability.
[0021]
In the above embodiment, the determination of whether the motor is in the power running state or the regenerative state is made based on the signal from the inverter control device 60. In addition, the current flowing through the SMR 30 and the SMR 32 is detected. A current sensor (not shown) may be provided to determine the current direction based on the detection result of the current sensor.
[0022]
As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.
[0023]
【The invention's effect】
As is clear from the above description, according to the present invention, the short circuit between the fixed contacts is prevented by approaching the arc generated between the two fixed contacts and the movable contact by the magnetic field from the permanent magnet. The relay interruption capability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a motor power supply device 10 to which a relay control device 70 according to an embodiment is applied.
FIG. 2 is a flowchart showing ON / OFF control of SRM by the relay control device 70;
FIG. 3 is a circuit configuration diagram of a motor power supply device 12 conventionally used in an electric vehicle.
FIG. 4 is a diagram showing a configuration of an SMR in which permanent magnets are arranged in the vicinity of a fixed contact and a movable contact.
[Explanation of symbols]
10 Motor power supply device, 20 Battery, 40 Inverter, 50 Three-phase AC motor, 52 Position sensor, 54 Current sensor, 60 Inverter control device, 70 Relay control device, 110, 120 Fixed contact, 112, 122 Fixed contact, 114 , 124 Movable contact, 130 Movable contact, 140 Plunger, 150,160 Permanent magnet, 170,180 arc.

Claims (1)

Two fixed contacts each having a fixed contact;
A movable contact having two movable contacts that are separable in a direction perpendicular to the arrangement direction of the two fixed contacts and arranged in a direction parallel to the arrangement direction of the fixed contacts ;
A drive unit for driving the movable contact;
Permanent magnets that are arranged to face each other with the fixed contact and the movable contact in between, and form a magnetic field in a direction perpendicular to a plane including the arrangement direction of the two fixed contacts and the arrangement direction of the two movable contacts. When,
Have
A relay control device for controlling a first control relay and a second control relay, which are connected to a positive electrode and a negative electrode of a battery, respectively, and open and close a connection between the battery and a motor driven by electric power supplied from the battery,
When the motor is in a power running state and a forward current that is the direction of the current in the power running state flows, the fixed state when the forward current flows between the first control relay and the second control relay. An arc generated between the fixed contact and the movable contact if a forward current flows through one control relay in which an arc generated between the contact and the movable contact extends in a direction away from each other by the action of the magnetic field. Opened before the other control relay that will be stretched in the direction approaching each other by the action of the magnetic field ,
When the motor is in a regenerative state and a reverse current, which is the direction of the current in the regenerative state, flows, the fixed state when the reverse current flows between the first control relay and the second control relay. An arc generated between the fixed contact and the movable contact if a reverse current flows through the other control relay in which an arc generated between the contact and the movable contact extends in a direction away from each other by the action of the magnetic field. Is opened before the one control relay that is stretched in the direction approaching each other by the action of the magnetic field .

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