Contact welding diagnostic device

Abstract

To provide a contactor deposition diagnostic device capable of suppressing erroneous determination of contactor deposition even when a motor rotates during diagnosis of the contactor deposition.SOLUTION: This contactor deposition diagnostic device comprises: a high-voltage battery 4 that is a main power source; an inverter 3 that receives power from the high-voltage battery 4 to drive a motor 2; a negative electrode side contactor 41 and a positive electrode side contactor 42 that cut electrical connection between the high-voltage battery 4 and the inverter 3; and a contactor disposition diagnostic unit 5 that switches disconnection of the negative electrode side contactor 41 and the positive electrode side contactor 42 at the time of activating a vehicle 1, diagnoses deposition of the negative electrode side contactor 41 and the positive electrode side contactor 42 on the basis of a change of a voltage applied to the inverter 3 at the time, and cuts off the negative electrode side contactor 41 and the positive electrode side contactor 42 when the rotational speed of the motor 2 is equal to or higher than a first rotational speed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a welding diagnosis device for a contactor. [Background technology]

[0002] Patent Document 1 describes a method of diagnosing a welding abnormality in either one of the positive contactors, including the positive contactor and precharge contactor, or the negative contactor, at the timing when a start-up command is output to start the vehicle, and diagnosing a welding abnormality in the other of the positive contactor and the negative contactor at the timing when a stop-up command is output to stop the vehicle.

[0003] In diagnosing contactor welding abnormalities, there is a method of using at least one contactor on each of the positive and negative sides, and diagnosing whether welding has occurred based on voltage fluctuations when one or both of the contactors are turned on and off.

[0004] For example, when starting the vehicle, if the positive contactor is turned off and the negative contactor is turned on and the voltage between the positive and negative terminals of the inverter rises, it is determined that the positive contactor is welded. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-169087 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in such a welding abnormality diagnosis method, when the motor rotates during the diagnosis of contactor welding, a voltage in the opposite direction to the voltage applied from the high-voltage battery is applied due to the counter electromotive force of the motor. Therefore, for example, even though the negative contactor is welded, the terminal voltage between the positive and negative electrodes of the inverter does not rise to the voltage for welding determination, and there is a risk of misjudging that the contactor is normal.

[0007] For example, when starting a vehicle on an uphill road, if the motor rotates in a way that it is dragged by the driving wheels due to the vehicle slipping down, such a phenomenon occurs. Also, in a vehicle that does not have a parking lock function and brakes the driving wheels only with the side brake, such an event is likely to occur.

[0008] Therefore, an object of the present invention is to provide a contactor welding diagnosis device that can suppress misjudgment of contactor welding even when the motor rotates during the diagnosis of contactor welding.

Means for Solving the Problems

[0009] To solve the above problems, the present invention provides a contactor welding diagnosis device for a vehicle including a high-voltage battery as a main power source, an inverter that is supplied with power from the high-voltage battery and drives a motor, and a contactor that disconnects and connects the electrical connection between the high-voltage battery and the inverter. The contactor welding diagnosis device includes a contactor welding diagnosis unit that switches the disconnection and connection of the contactor when the vehicle starts and diagnoses the welding of the contactor based on the change in the voltage applied to the inverter at that time. The contactor welding diagnosis unit is In the contact welding diagnosis, when the voltage applied to the inverter becomes equal to or higher than the welding determination voltage value, it is determined that the contact is welded, and the welding determination voltage value is set according to the rotational speed of the motor. as follows.

Effects of the Invention

[0010] Thus, according to the present invention, even when the motor rotates during the diagnosis of contactor welding, misjudgment of contactor welding can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

[0012] A welding diagnosis apparatus for a contact according to an embodiment of the present invention is a welding diagnosis apparatus for a contact of a vehicle including a high-voltage battery as a main power source, an inverter that is supplied with power from the high-voltage battery and drives a motor, and a contact that disconnects and connects an electrical connection between the high-voltage battery and the inverter. When starting the vehicle, the welding diagnosis unit for the contact that switches the disconnection and connection of the contact and diagnoses the welding of the contact based on the change in the voltage applied to the inverter at that time is provided. The welding diagnosis unit for the contact is configured to disconnect the contact when the rotational speed of the motor is equal to or higher than a first rotational speed during the execution of the welding diagnosis for the contact.

[0013] Thereby, the welding diagnosis apparatus for a contact according to an embodiment of the present invention can suppress an erroneous determination of the welding of the contact even when the motor rotates during the diagnosis of the welding of the contact. EXAMPLE

[0014] Hereinafter, with reference to the drawings, a welding diagnosis apparatus for a contactor according to an embodiment of the present invention will be described in detail.

[0015] In FIG. 1, a vehicle 1 equipped with a welding diagnosis apparatus for a contactor according to an embodiment of the present invention includes a motor 2, an inverter 3, a high-voltage battery 4, and a contactor welding diagnosis unit 5.

[0016] The motor 2 is, for example, a synchronous motor including a rotor in which a plurality of permanent magnets are embedded and a stator around which a stator coil is wound. When three-phase AC power is applied to the stator coil of the motor 2, a rotating magnetic field is formed in the stator, and the rotor rotates by this rotating magnetic field to generate a driving force.

[0017] In addition, the motor 2 is driven so as to use the rotational resistance during power generation for braking the vehicle 1. Thereby, the motor 2 has a function of being able to generate electric power by regeneration. In this way, the motor 2 also functions as a generator and can generate electric power for charging the high-voltage battery 4.

[0018] The rotating shaft of the motor 2 is connected to the driving wheels 6 via a reduction gear, a driving shaft, etc. (not shown). The motor 2 drives the driving wheels 6 via a reduction gear, a driving shaft, etc.

[0019] A rotation speed sensor 21 for detecting the rotation speed of the motor 2 is provided on the motor 2. The rotation speed sensor 21 outputs the rotation in the rotation direction when the vehicle 1 is moving forward as a positive rotation speed.

[0020] The inverter 3 supplies three-phase AC power to the motor 2. Further, the inverter 3 converts the three-phase AC power generated by the motor 2 into DC power to charge the high-voltage battery 4.

[0021] A smoothing capacitor 31 is connected between the positive and negative electrodes of the input terminals connecting the inverter 3 and the high-voltage battery 4. The smoothing capacitor 31 smooths the voltage of the DC power generated between the positive and negative electrodes.

[0022] The high-voltage battery 4 is composed of, for example, a nickel storage battery, a lithium storage battery, etc., and is configured by connecting a plurality of cells in series. The high-voltage battery 4 supplies power to the motor 2 via the inverter 3.

[0023] A negative electrode side contactor 41 as a contactor is provided on the negative electrode side between the inverter 3 and the high-voltage battery 4. A positive electrode side contactor 42 as a contactor is provided on the positive electrode side between the inverter 3 and the high-voltage battery 4. A circuit in which a precharge contactor 43 and a precharge resistor 44 are connected in series is connected to the positive electrode side contactor 42 in parallel with the positive electrode side contactor 42.

[0024] The negative electrode side contactor 41 and the positive electrode side contactor 42 take either an on state in which the inverter 3 and the high-voltage battery 4 are electrically connected or an off state in which the inverter 3 and the high-voltage battery 4 are electrically disconnected according to the control of the contactor welding diagnosis unit 5.

[0025] The precharge contactor 43 takes either an on state in which the precharge resistor 44 is connected in parallel to the positive electrode side contactor 42 or an off state in which the precharge resistor 44 is electrically disconnected from the positive electrode side contactor 42 according to the control of the contactor welding diagnosis unit 5.

[0026] For example, the precharge contactor 43 is controlled to take an on state before the motor 2 operates and an off state after the positive electrode side contactor 42 takes an on state.

[0027] The contactor welding diagnosis unit 5 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input port, and an output port.

[0028] In the ROM of the contact welding diagnosis unit 5, there is stored a program for causing the computer unit to function as the contact welding diagnosis unit 5, together with various control constants, various maps, and the like. That is, by the CPU executing the program stored in the ROM, the computer unit functions as the contact welding diagnosis unit 5.

[0029] Connected to the input port of the contact welding diagnosis unit 5 are various sensors including the aforementioned inverter 3, the rotational speed sensor 21, and a vehicle speed sensor 51. The vehicle speed sensor 51 detects the speed of the vehicle 1.

[0030] On the other hand, connected to the output port of the contact welding diagnosis unit 5 are various controlled objects including the aforementioned negative electrode side contact 41, positive electrode side contact 42, and precharge contact 43.

[0031] In this embodiment, the contact welding diagnosis unit 5 performs a contact welding diagnosis for diagnosing whether the negative electrode side contact 41 and the positive electrode side contact 42 are welded.

[0032] The contact welding diagnosis unit 5 performs a contact welding diagnosis of the negative electrode side contact 41 and the positive electrode side contact 42, for example, when the vehicle 1 is started.

[0033] The contact welding diagnosis unit 5 determines that a contact other than the one that is in the on state is welded, for example, when the voltage between the positive electrode side and the negative electrode side of the input terminal of the inverter 3 exceeds a predetermined welding determination voltage value when either the negative electrode side contact 41 or the positive electrode side contact 42 is in the on state.

[0034] During the execution of the contact welding diagnosis, when the motor rotation speed becomes equal to or higher than a predetermined first rotation speed, the contact welding diagnosis unit 5 stops the contact welding diagnosis and turns off the negative electrode side contact 41 and the positive electrode side contact 42. The first rotation speed is the lower limit value of the motor rotation speed at which a counter electromotive voltage from the motor 2 that affects the contact welding diagnosis is generated, and is, for example, 100 rpm.

[0035] During the execution of the contactor welding diagnosis, when the speed of the vehicle 1 becomes equal to or higher than a predetermined first vehicle speed, the contactor welding diagnosis unit 5 stops the contactor welding diagnosis and turns off the negative-side contactor 41 and the positive-side contactor 42. The first vehicle speed is the lower limit value of the vehicle speed at which a counter electromotive voltage from the motor 2 that affects the contactor welding diagnosis is generated, and is, for example, 1 km / h.

[0036] Thus, in this embodiment, during the execution of the contactor welding diagnosis, when the motor rotation speed becomes equal to or higher than a predetermined first rotation speed, the contactor welding diagnosis unit 5 turns off the negative-side contactor 41 and the positive-side contactor 42.

[0037] When there is a possibility that the contactor welding diagnosis cannot be normally performed due to the counter electromotive voltage generated by the rotation of the motor 2, the contactor is turned off and the start of the vehicle 1 is stopped.

[0038] This can prevent misjudgment of the contactor welding and prevent the vehicle 1 from starting with the contactor welded.

[0039] Also, during the execution of the contactor welding diagnosis, when the speed of the vehicle 1 becomes equal to or higher than a predetermined first vehicle speed, the contactor welding diagnosis unit 5 turns off the negative-side contactor 41 and the positive-side contactor 42.

[0040] Since the drive wheel 6 and the motor 2 are directly connected, if there is a vehicle speed (higher than zero), rotation of the motor 2 will occur, and a counter electromotive voltage will be generated due to the rotation of the motor 2. As a result, when the negative contactor 41 and the positive contactor 42 are in the on state, a current will flow from the inverter 3 side to the high-voltage battery 4 side, and the way the voltage changes between the positive and negative sides of the input terminals of the inverter 3 will be different from normal. For this reason, welding of the contactor cannot be detected, and there is a risk that the vehicle 1 will start with the contactor welded. Therefore, when a counter electromotive voltage is generated in the contactor, by turning off the contactor, false determination of contactor welding can be suppressed.

[0041] As another aspect of the present embodiment, during the execution of the contactor welding diagnosis, when the speed of the vehicle 1 is equal to or higher than the first vehicle speed, or the motor rotation speed is equal to or higher than the first rotation speed, and a counter electromotive voltage of the motor 2 is generated, the contactor welding diagnosis unit 5 sets a welding determination voltage value according to the speed of the vehicle 1 or the motor rotation speed.

[0042] Note that the welding determination voltage value is set to a lower value as the speed of the vehicle 1 is higher, and is set to a lower value as the motor rotation speed is higher.

[0043] During the execution of the contactor welding diagnosis, when the speed of the vehicle 1 becomes equal to or higher than a second vehicle speed that is higher than the first vehicle speed, the contactor welding diagnosis unit 5 stops the contactor welding diagnosis and turns off the negative contactor 41 and the positive contactor 42.

[0044] During the execution of the contactor welding diagnosis, when the motor rotation speed becomes equal to or higher than a second rotation speed that is higher than the first rotation speed, the contactor welding diagnosis unit 5 stops the contactor welding diagnosis and turns off the negative contactor 41 and the positive contactor 42.

[0045] Regarding the welding diagnosis determination process by the welding diagnosis device for the contactor according to another aspect of the present embodiment configured as described above, it will be described with reference to FIG. 2. Note that the welding diagnosis determination process described below starts when the contactor welding diagnosis is started, is executed at a preset time interval, and the execution stops when the contactor welding diagnosis ends.

[0046] In step S101, the contactor welding diagnosis unit 5 determines whether the speed of the vehicle 1 is equal to or higher than the first vehicle speed, or whether the motor rotation speed is equal to or higher than the first rotation speed.

[0047] If it is determined that the speed of the vehicle 1 is equal to or higher than the first vehicle speed, or the motor rotation speed is equal to or higher than the first rotation speed, the contactor welding diagnosis unit 5 executes the process of step S102. If it is determined that the speed of the vehicle 1 is not equal to or higher than the first vehicle speed and the motor rotation speed is not equal to or higher than the first rotation speed, the contactor welding diagnosis unit 5 ends the welding diagnosis determination process.

[0048] In step S102, the contactor welding diagnosis unit 5 determines whether the speed of the vehicle 1 is equal to or higher than the second vehicle speed, or whether the motor rotation speed is equal to or higher than the second rotation speed.

[0049] If it is determined that the speed of the vehicle 1 is equal to or higher than the second vehicle speed, or the motor rotation speed is equal to or higher than the second rotation speed, the contactor welding diagnosis unit 5 executes the process of step S103. If it is determined that the speed of the vehicle 1 is not equal to or higher than the second vehicle speed and the motor rotation speed is not equal to or higher than the second rotation speed, the contactor welding diagnosis unit 5 executes the process of step S104.

[0050] In step S103, the contactor welding diagnosis unit 5 stops the contactor welding diagnosis and sets the negative electrode side contactor 41 and the positive electrode side contactor 42 to the off state. After executing the process of step S103, the contactor welding diagnosis unit 5 ends the welding diagnosis determination process.

[0051] In step S104, the contactor welding diagnosis unit 5 sets the welding determination voltage value according to the vehicle speed or the motor rotation speed. After executing the process of step S104, the contactor welding diagnosis unit 5 ends the welding diagnosis determination process.

[0052] The operation by such a welding diagnosis determination process will be described with reference to FIGS. 3 and 4. FIG. 3 is a time chart showing the change in voltage between the positive electrode side and the negative electrode side of the input terminal of the inverter 3 when there is no counter electromotive voltage of the motor 2. Here, the case where the negative electrode side contactor 41 is welded is shown.

[0053] In the figure, the solid lines of the positive electrode side contactor and the negative electrode side contactor indicate the control states, and the dotted lines indicate the actual states. That is, the state of the negative electrode side contactor 41 is off in terms of control, but is actually on because it is welded.

[0054] At time t1, when the positive electrode side contactor 42 is turned on for contactor welding diagnosis, since the negative electrode side contactor 41 is welded, the voltage value between the positive electrode and the negative electrode rises, and at time t2, it is determined that the negative electrode side contactor 41 is welded because the voltage exceeds the welding determination voltage value.

[0055] FIG. 4 is a time chart showing the change in voltage between the positive electrode side and the negative electrode side of the input terminal of the inverter 3 when there is a counter electromotive voltage of the motor 2. Here, the case where the negative electrode side contactor 41 is welded is shown.

[0056] Similar to FIG. 3, in the figure, the solid lines of the positive electrode side contactor and the negative electrode side contactor indicate the control states, and the dotted lines indicate the actual states. That is, the state of the negative electrode side contactor 41 is off in terms of control, but is actually on because it is welded.

[0057] From time t10, the motor rotation speed or vehicle speed increases, and when the motor 2 rotates, a counter electromotive voltage is generated in the motor 2. As the rotation of the motor 2 continues to increase until time t11, the counter electromotive voltage of the motor 2 also increases. Along with this, the welding determination voltage value also decreases according to the motor rotation speed or vehicle speed.

[0058] At time t12, when the positive electrode side contact 42 is turned on for contact welding diagnosis, since the negative electrode side contact 41 is welded, the voltage value between the positive electrode and the negative electrode increases. At time t13, when the voltage value exceeds the welding determination voltage value, it is determined that the negative electrode side contact 41 is welded.

[0059] In this way, even when the counter electromotive voltage of the motor 2 is generated, the contact welding diagnosis can be normally carried out.

[0060] In this way, in another aspect of this embodiment, during the implementation of the contact welding diagnosis, the contact welding diagnosis unit 5 sets the welding determination voltage value according to the vehicle speed or motor rotation speed when the speed of the vehicle 1 is equal to or higher than the first vehicle speed, or the motor rotation speed is equal to or higher than the first rotation speed.

[0061] Thereby, the welding determination voltage value is set to a value corresponding to the vehicle speed or motor rotation speed of the vehicle 1, and even when the counter electromotive voltage of the motor 2 is generated, the contact welding diagnosis can be normally carried out.

[0062] Also, the welding determination voltage value is set to a lower value as the vehicle speed of the vehicle 1 is higher, and is set to a lower value as the motor rotation speed is higher.

[0063] Thereby, an appropriate welding determination voltage value corresponding to the counter electromotive voltage of the motor 2 can be set, and even when the counter electromotive voltage of the motor 2 is generated, the contact welding diagnosis can be normally carried out.

[0064] Further, during the execution of the contactor welding diagnosis, when the speed of the vehicle 1 becomes equal to or higher than the second vehicle speed, or when the motor rotation speed becomes equal to or higher than the second rotation speed, the contactor welding diagnosis unit 5 stops the contactor welding diagnosis and turns off the negative-side contactor 41 and the positive-side contactor 42.

[0065] When the back electromotive force of the motor 2 is too high, the voltage between the positive electrode side and the negative electrode side of the input terminal of the inverter 3 becomes too low, making it difficult to execute the contactor welding diagnosis. Therefore, the contactor is turned off. This can prevent the vehicle 1 from running with the contactor welded.

[0066] In this embodiment, an example in which the contactor welding diagnosis unit 5 makes various determinations and calculations based on various sensor information has been described. However, the present invention is not limited to this. The vehicle 1 is provided with a communication unit capable of communicating with an external device such as an external server, and various determinations and calculations are performed by the external device based on the detection information of various sensors transmitted from the communication unit. The determination result and calculation result are received by the communication unit, and various controls may be performed using the received determination result and calculation result.

[0067] Although embodiments of the present invention have been disclosed, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. It is intended that all such modifications and equivalents be included in the following claims.

Explanation of Reference Numerals

[0068] 1 Vehicle 2 Motor 3 Inverter 4 High-voltage battery 5 Contactor welding diagnosis unit 6 Driving wheel 21 Rotation speed sensor 41 Negative-side contactor (contactor) 42 Positive-side contactor (contactor) 43 Precharge contactor 44 Precharge resistor 51 Vehicle speed sensor

Claims

1. A high-voltage battery as the main power source, an inverter that is supplied with power from the high-voltage battery and drives a motor, a contactor that disconnects and connects the electrical connection between the high-voltage battery and the inverter, and a contactor welding diagnosis device for a vehicle comprising: a contactor welding diagnosis unit that switches the disconnection and connection of the contactor when the vehicle starts, and performs contactor welding diagnosis for diagnosing welding of the contactor based on a change in voltage applied to the inverter at that time, the contactor welding diagnosis unit determines that the contactor is welded when the voltage applied to the inverter in the contactor welding diagnosis is equal to or higher than a welding determination voltage value, and sets the welding determination voltage value according to the rotational speed of the motor. A contactor welding diagnosis device for a contactor.

2. The contactor welding diagnosis device according to claim 1, wherein the contactor welding diagnosis unit sets the welding determination voltage value to a lower value as the rotational speed of the motor is higher.

3. During the implementation of the contactor welding diagnosis, when the rotational speed of the motor is equal to or higher than a first rotational speed, the contactor welding diagnosis unit sets the welding determination voltage value according to the rotational speed of the motor, and when the rotational speed of the motor is equal to or higher than a second rotational speed higher than the first rotational speed, the contactor welding diagnosis device according to claim 1 or claim 2, which disconnects the contactor.

4. A high-voltage battery as the main power source, an inverter that is supplied with power from the high-voltage battery and drives a motor, a contactor that disconnects and connects the electrical connection between the high-voltage battery and the inverter, and a contactor welding diagnosis device for a vehicle comprising: a contactor welding diagnosis unit that switches the disconnection and connection of the contactor when the vehicle starts, and performs contactor welding diagnosis for diagnosing welding of the contactor based on a change in voltage applied to the inverter at that time, the motor is directly connected to drive wheels that drive the vehicle, the contactor welding diagnosis unit determines that the contactor is welded when the voltage applied to the inverter in the contactor welding diagnosis is equal to or higher than a welding determination voltage value, and sets the welding determination voltage value according to the speed of the vehicle. A contactor welding diagnosis device for a contactor.

5. The contact welding diagnosis unit is the contact welding diagnosis apparatus according to claim 4, which sets the welding determination voltage value to a lower value as the speed of the vehicle is higher.

6. The contact welding diagnosis unit sets the welding determination voltage value according to the speed of the vehicle when the speed of the vehicle is equal to or higher than a first vehicle speed during the execution of the contact welding diagnosis, and cuts the contact when the speed of the vehicle is equal to or higher than a second vehicle speed higher than the first vehicle speed. The contact welding diagnosis apparatus according to claim 4 or claim 5.

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