Relay control system

Abstract

The relay is turned off at a more appropriate time. [Solution] A relay control system comprising a first control device that operates using power from a battery and transmits a relay disconnection request, and a second control device that turns off the relay when it receives a disconnection request from the first control device, wherein the second control device turns off the relay when communication with the first control device is interrupted for a first hour and the battery voltage is below a predetermined voltage. As a result, the relay can be turned off at a more appropriate timing.

Description

Technical Field

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[0001] The present disclosure relates to a relay control system.

Background Art

[0002] Conventionally, as this type of relay control system, there has been proposed a system including a first control device (EV-ECU) that transmits a disconnection request for a relay (SMR), and a second control device (battery ECU) that turns off the relay when receiving the disconnection request via communication with the first control device (see, for example, Patent Document 1). In this system, when the communication between the first control device and the second control device is interrupted, the second control device turns off the relay after a predetermined time has elapsed since the interruption. Thereby, the relay can be turned off when the communication between the first control device and the second control device is interrupted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above relay control system, the relay is disconnected when the communication between the first control device and the second control device is interrupted. However, the interruption of the communication between the first control device and the second control device may occur when the voltage of the battery that supplies power to the first control device temporarily decreases. Also, it may be temporary and be resolved after a while. Therefore, turning off the relay at a more appropriate timing has been recognized as an important issue.

[0005] The main object of the relay control system of the present disclosure is to turn off the relay at a more appropriate timing.

Means for Solving the Problems

[0006] The relay control system of this disclosure employs the following means to achieve the main objective described above.

[0007] The relay control system of this disclosure is A relay control system comprising: a first control device that operates using power from a battery and transmits a relay disconnection request; and a second control device that turns off the relay when it receives the disconnection request from the first control device via communication, The second control device shall turn off the relay if the communication with the first control device is interrupted for a first hour and the battery voltage is below a predetermined voltage. This is the gist of it.

[0008] In the relay control system of this disclosure, the second control unit turns off the relay when communication with the first control unit is interrupted for a first hour and the battery voltage falls below a predetermined voltage. As a result, the relay can be turned off at a more appropriate timing.

[0009] In the relay control system of this disclosure, the second control device may turn off the relay if the communication with the first control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, and the interruption in communication with the first control device continues for a second hour, which is longer than the first hour. This allows the relay to be turned off at a more appropriate timing.

[0010] In this case, the second control device may be equipped with a notification device for notifying information, and the second control device may control the notification device to notify that the relay will be turned off if the communication with the first control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, and the interruption in communication with the first control device continues for a second hour. This way, the vehicle user can be notified that the relay has been turned off, thereby improving user convenience.

[0011] Furthermore, in the relay control system of this disclosure, if the communication with the first control device is interrupted for a first hour, and the battery voltage is below the predetermined voltage, the second control device may send a request to the first control device via the communication to send the shut-off request. If the communication with the first control device is still interrupted after a third hour has elapsed since the transmission of the request, the second control device may turn off the relay. This allows the relay to be turned off at a more appropriate timing.

[0012] Furthermore, in the relay control system of this disclosure, if the second control device is interrupted for a first hour and the battery voltage is below a predetermined voltage, and the interruption in communication with the first control device continues for a second hour longer than the first hour, the second control device may send a request to the first control device via communication to send the shut-off request. If the communication with the first control device is still interrupted after a third hour has elapsed since the transmission of the request, the second control device may turn off the relay. This allows the relay to be turned off at a more appropriate timing. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing the configuration of an electric vehicle equipped with a control device according to an embodiment of the disclosure. [Figure 2] This flowchart shows an example of a processing routine executed by the battery ECU. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of an electric vehicle equipped with a relay control system according to an embodiment of this disclosure. As shown in the figure, the electric vehicle 20 includes a motor 32, an inverter 34, a battery 36, a battery electronic control unit (hereinafter referred to as "battery ECU") 37, a system main relay (relay) SMR, an auxiliary battery (battery) 40, a DC / DC converter 48, a step-up / step-down converter 50, an airbag electronic control unit (hereinafter referred to as "ARGECU") 68, and an electronic control unit (hereinafter referred to as "ECU") 70. In this embodiment, the relay control system mainly consists of the battery ECU 37 and the ECU 70. In Figure 1, solid arrows indicate direct lines as signal wiring that exchange signals one-to-one. Dashed arrows indicate communication lines (for example, communication lines for CAN communication) as signal wiring that can exchange signals with multiple devices.

[0015] The motor 32 is configured as a synchronous regenerative motor and comprises a rotor with permanent magnets embedded in a rotor core and a stator with three-phase coils wound around a stator core. The rotor of this motor 32 is connected to a drive shaft 26 which is connected to the drive wheels 22a and 22b via a differential gear 24.

[0016] The inverter 34 is connected to the motor 32 and also to the high-voltage side power line (second power line) 38a. This inverter 34 is configured as a well-known inverter circuit having six transistors and six diodes. The motor 32 is rotationally driven by switching control of several switching elements (not shown) of the inverter 34. The inverter 34 is connected to the ECU 70 via a communication line.

[0017] The buck-boost converter 50 is connected to the high-voltage side power line 38a and the low-voltage side power line (first power line) 38b, and is configured as a well-known buck-boost converter circuit having two transistors and two diodes and a reactor that constitute the upper and lower arms. The buck-boost converter 50 adjusts the ratio of the on-times of the two transistors that constitute the upper and lower arms by the ECU 70, thereby boosting the power of the low-voltage side power line 38b and supplying it to the high-voltage side power line 38a, or lowering the voltage of the high-voltage side power line 38a and supplying it to the low-voltage side power line 38b. Although not shown, smoothing capacitors are attached to the positive and negative lines of the high-voltage side power line 38a. Smoothing capacitors 39 are attached to the positive and negative lines of the low-voltage side power line 38b.

[0018] Battery 36 is configured as a lithium-ion or nickel-metal hydride secondary battery, for example, with a rated voltage of several hundred volts. Battery 36 is managed by the battery ECU 37.

[0019] The battery ECU 37, although not shown in the diagram, is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and communication ports. The battery ECU 37 is connected to the system main relay SMR via a direct wire. The battery ECU 37 receives the voltage Vb from the voltage sensor 36a attached between the terminals of the battery 36 (voltage between the terminals of the battery 36), the current Ib from the current sensor 36b attached to the output terminal of the battery 36, and the voltage VL from the voltage sensor 40a that detects the voltage between the terminals of the auxiliary battery 40, via the communication line and input port. The battery ECU 37 outputs signals such as a signal to illuminate the warning light (notification device) 46 installed in the passenger compartment via the output port and communication line. The battery ECU 37 also outputs a drive signal to the system main relay SMR via the output port and direct wire.

[0020] The system main relay SMR is connected to the low-voltage side power line 38b. This system main relay SMR has a positive-side relay SMRB provided on the positive line of the low-voltage side power line 38b and a negative-side relay SMRG provided on the negative line of the low-voltage side power line 38b.

[0021] The auxiliary battery 40 is configured as, for example, a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or a lead-acid battery with a rated voltage of about a dozen volts, and is connected to the auxiliary-side power line 42 together with an auxiliary device (not shown), a DC / DC converter 48, a battery ECU 37, an ABG ECU 60, and an ECU 70.

[0022] The DC / DC converter 48 is connected to the low-voltage side power line 38b and the auxiliary-side power line 42. This DC / DC converter 48 steps down the power of the low-voltage side power line 38b and supplies it to the auxiliary-side power line 42, or steps up the power of the auxiliary-side power line 42 and supplies it to the low-voltage side power line 38b. The DC / DC converter 48 is connected to the ECU 70 via a communication line.

[0023] The ARG ECU 68 is configured as a microprocessor centered around a CPU, although not shown. In addition to the CPU, it includes a ROM that stores a processing program, a RAM that temporarily stores data, a flash memory that stores and holds data, an input / output port, and a communication port. The ARG ECU 68 controls an airbag (not shown) and determines a vehicle collision. The ARG ECU 68 is connected to the ECU 70 via a communication line.

[0024] Although not shown in the diagram, the ECU70 is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and communication ports. The ECU70 is connected to the inverter 34, DC / DC converter 48, buck-boost converter 50, and ARGECU60 via communication lines. The ECU70 is connected to the battery ECU37 via a direct line and communication lines. Signals from various sensors are input to the ECU70 via communication lines and input ports. Examples of signals input to the ECU70 include the rotational position θm from a rotational position detection sensor (e.g., resolver) 32a that detects the rotational position of the rotor of the motor 32. Another example is the voltage VL of the capacitor 39 (low-voltage side power line 38b) from a voltage sensor 39a attached between the terminals of the capacitor 39. Other signals that can be identified from the ECU 70 include the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 which detects the operating position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 which detects the amount the accelerator pedal 83 is pressed, the brake pedal position BP from the brake pedal position sensor 86 which detects the amount the brake pedal 85 is pressed, and the vehicle speed V from the vehicle speed sensor 87. Various control signals are output from the ECU 70 via communication lines and output ports. Examples of signals output from the ECU 70 include control signals to the transistors of the inverter 34, control signals to the DC / DC converter 48, and control signals to the step-up / step-down converter 50.

[0025] In the electric vehicle 20 configured in this way, the system main relay SMR is turned on and the vehicle is driven by power from the motor 32. When turning on the system main relay SMR, the ECU 70 sends a connection request for the system main relay SMR to the battery ECU 37 via communication lines and direct wires. Upon receiving the connection request for the system main relay SMR via communication lines and direct wires, the battery ECU 37 supplies drive current to the direct wires connected to the system main relay SMR to turn on the system main relay SMR (turning on both the positive side relay SMRB and the negative side relay SMRG).

[0026] When ARGECU68 detects a vehicle collision, it transmits a collision detection signal to ECU70 via the communication line. Upon receiving the collision detection signal, ECU70 transmits a request to shut down the system main relay SMR to battery ECU37 via the communication line and the direct wire. Upon receiving the request to shut down the system main relay SMR, battery ECU37 stops supplying drive current to the direct wire connected to the system main relay SMR, thereby turning off the system main relay SMR (turning off at least one of the positive side relay SMRB and the negative side relay SMRG).

[0027] Next, we will describe the operation of the electric vehicle 20 configured in this way, in particular, the operation when a communication interruption occurs between the battery ECU 37 and the ECU 70. Figure 2 is a flowchart showing an example of a processing routine executed by the battery ECU. It is executed when both direct line communication and communication via communication lines between the battery ECU 37 and the ECU 70 are interrupted for a first time tref1. The first time tref1 can be twice or three times the signal transmission period in communication using communication lines, for example, a time of several tens of milliseconds to several seconds.

[0028] When this routine is executed, the battery ECU 37 receives the voltage VL of the auxiliary battery 40 from the voltage sensor 40a (S100). Next, the battery ECU 37 determines whether the voltage VL is less than a predetermined voltage Vref (S110). The predetermined voltage Vref is a voltage predetermined as the lower limit of the power supply voltage range when the auxiliary battery 40 is functioning normally. If a problem occurs with the auxiliary battery 40 or the auxiliary power line 42, such as in a vehicle collision, the voltage of the auxiliary battery 40 may drop. Therefore, S110 is a process to determine whether there is a high probability that a vehicle collision has occurred. If the voltage VL is equal to or greater than the predetermined voltage Vref, the battery ECU 37 determines that there is a low probability that a vehicle collision has occurred and terminates this routine.

[0029] In S110, when the voltage VL is below a predetermined voltage Vref, the battery ECU 37 determines whether or not it has received a request from the ECU 70 to shut down the system main relay SMR (S120). This routine is executed when communication between the battery ECU 37 and the ECU 70 is interrupted, but the interruption may be temporary and then resume. In S120, the ECU 37 determines whether or not it has received a request from the ECU 70 to shut down the system main relay SMR, anticipating such a resumption of communication. When the battery ECU 37 receives a shut-down request, it shuts down the system main relay SMR and sends a signal to illuminate the warning light 46 (S170), and then terminates this routine. Through this process, the system main relay SMR can be quickly shut down in response to instructions from the ECU 70, and the warning light 46 can be illuminated to inform the vehicle user that the system main relay SMR has been shut down.

[0030] If the battery ECU 37 does not receive a shutdown request for the system main relay SMR in S120, it determines whether the elapsed time tl since communication with the ECU 70 was interrupted is greater than or equal to the second time tref2 (S130). The second time tref2 is a predetermined time that is longer than the first time tref1. If the elapsed time tl is less than the second time tref2, the process returns to S100, and the processes from S100 to S130 are repeated until the voltage VL is determined to be greater than or equal to a predetermined voltage Vref in S110, or a shutdown request is received from the ECU 70 in S120. If the voltage VL is determined to be greater than or equal to a predetermined voltage Vref in S110, the routine is terminated as described above. If a shutdown request is received in S120, the system main relay SMR is turned off and a signal is sent to turn on the warning light 46 (S170), and the routine is terminated as described above.

[0031] Then, when the battery ECU 37 is not free from the condition where the voltage VL is below the predetermined voltage Vref and has not received a shutdown request from ECU 70, and the elapsed time tl exceeds the second time tref2, it determines that there is a very high possibility that some kind of malfunction has occurred in the communication line, direct line, or auxiliary battery 40 connected to ECU 70 due to a vehicle collision or the like, and sends a request to ECU 70 to send a shutdown request for the system main relay SMR (S140). When ECU 70 receives a request from battery ECU 37 to send a shutdown request for the system main relay SMR, it sends the shutdown request for the system main relay SMR to battery ECU 37 via communication through the direct line and communication line.

[0032] Then, the battery ECU 37 determines whether or not it has received a request from the ECU 70 to shut down the system main relay SMR (S150). When the interruption in communication between the battery ECU 37 and the ECU 70 via the direct line and the communication line is resolved, the battery ECU 37 can receive the request to shut down the system main relay SMR from the ECU 70. However, when the interruption in communication between the battery ECU 37 and the ECU 70 via the direct line and the communication line is not resolved, the battery ECU 37 cannot receive the request to shut down the system main relay SMR from the ECU 70. Therefore, S150 is a process to determine whether or not the interruption in communication between the battery ECU 37 and the ECU 70 via the direct line and the communication line has been resolved and restored.

[0033] If the battery ECU 37 does not receive a system main relay SMR shutdown request from the ECU 70 in S150, it determines that the communication interruption between the battery ECU 37 and the ECU 70 via the direct line and communication line has not been resolved, and determines in S160 whether the elapsed time tr since sending the request to send the system main relay SMR shutdown request is equal to or greater than the third time tref3. If the elapsed time tr is less than the third time tref3, the battery ECU 37 repeats S150 and S160 until it receives a shutdown request from the ECU 70 in S150, or until the elapsed time tr is equal to or greater than the third time tref3 in S160. When the battery ECU 37 receives a shutdown request from the ECU 70 in S150, it determines that the interruption in communication between the battery ECU 37 and the ECU 70 via the direct line and communication line has been resolved and that it has received a shutdown request from the ECU 70. It then immediately shuts down the system main relay SMR and sends a signal to illuminate the warning light 46 (S170), ending this routine. This process allows the system main relay SMR to be quickly shut down in response to instructions from the ECU 70, and the warning light 46 to illuminate, informing the vehicle user that the system main relay SMR has been shut down.

[0034] Furthermore, if the elapsed time tr is 3 hours (tref3) or longer in S160, the battery ECU 37 turns off the system main relay SMR and sends a signal to illuminate the warning light 46 (S170), and then terminates this routine. Through this process, the battery ECU 37 can turn off the system main relay SMR and illuminate the warning light 46 to inform the vehicle user that the system main relay SMR has been turned off, even if the communication interruption with the ECU 70 has not been resolved.

[0035] According to the relay control system of this embodiment described above, when communication with the ECU 70 is interrupted for the first hour tref1, the battery ECU 37 can turn off the system main relay SMR at a more appropriate timing by turning off the system main relay SMR when the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref.

[0036] Furthermore, if communication with the ECU 70 is interrupted for a first hour (tref1) and the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, the battery ECU 37 can turn off the system main relay SMR at a more appropriate timing by turning off the system main relay SMR when the interruption in communication with the ECU 70 continues for a second hour (tref2) which is longer than the first hour (tref1).

[0037] Furthermore, the battery ECU 37 is equipped with a warning light 46, and if communication with the ECU 70 is interrupted for a first hour (tref1) and the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, the battery ECU 37 will illuminate the warning light 46 to notify the user that the relay should be turned off if the interruption in communication with the ECU 70 continues for a second hour (tref2) which is longer than the first hour (tref1), thereby improving user convenience.

[0038] Furthermore, if communication with ECU70 is interrupted for 1 hour tref1, and the voltage VL of the auxiliary battery 40 is below a predetermined voltage Vref, the battery ECU37 sends a request to ECU70 to send a cutoff request via communication. If communication with ECU70 is still interrupted after 3 hours tref3 has elapsed since the request was sent, the system main relay SMR is turned off, thereby enabling the system main relay SMR to be turned off at a more appropriate timing.

[0039] Furthermore, if communication with the ECU 70 is interrupted for a first time (tref1) and the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, and the interruption of communication with the ECU 70 continues for a second time (tref2) which is longer than the first time (tref1), the battery ECU 37 sends a request to the ECU 70 to send a cutoff request via communication. If communication with the ECU 70 is still interrupted after a third time (tref3) has elapsed since the request was sent, the system main relay SMR is turned off, allowing the system main relay SMR to be turned off at a more appropriate timing.

[0040] In the embodiment described above, if communication with the ECU 70 is interrupted for a first time tref1 and the processing routine is executed, and in S110 the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, then S120 to S170 are executed. However, if the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, S170 may be executed without executing S120 to S160.

[0041] In the embodiment described above, when communication with the ECU 70 is interrupted for a first time tref1 and the processing routine is executed, and in S110 the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, if the elapsed time tl since the interruption of communication with the ECU 70 is 2nd time tref2 or more, S140 to S170 are executed. However, S140 to S160 may be omitted and S170 may be executed instead.

[0042] In the embodiment described above, the electric vehicle 20 is equipped with a warning light 46, and the warning light 46 is illuminated when the system main relay SMR is turned off in S170. However, the electric vehicle 20 may be equipped with a display that shows information or a speaker that outputs information by voice instead of, or together with, the warning light 46, when the system main relay SMR is turned off in S170, instead of illuminating the warning light 46, or the warning light 46 is illuminated and a message indicating that the system main relay SMR is being turned off is displayed on the display, or a voice message indicating that the system main relay SMR is being turned off is output from the speaker. Alternatively, in S170, only the process of turning off the system main relay SMR may be executed without illuminating the warning light 46.

[0043] In the embodiment described above, the battery ECU 37 sends a request to send a shutdown request when communication with the ECU 70 is interrupted for a first time tref1, the processing routine is executed, the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref, and the elapsed time tl since the interruption of communication with the ECU 70 is 2 hours tref2 or more. However, the battery ECU 37 may send a request to send a shutdown request without determining whether the elapsed time tl is 2 hours tref2 or more (without executing S130) when communication with the ECU 70 is interrupted for a first time tref1, the processing routine is executed, and the voltage VL of the auxiliary battery 40 is less than a predetermined voltage Vref.

[0044] In the embodiments described above, the control target in the relay control system of this disclosure is the system main relay SMR. However, it may be applied to relays attached to other wiring instead of the system main relay SMR.

[0045] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, ECU70 corresponds to the "first control device" and battery ECU37 corresponds to the "second control device".

[0046] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0047] Although the embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and it is of course possible to implement it in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0048] This disclosure can be used in industries such as the manufacturing of relay control systems. [Explanation of Symbols]

[0049] 20 Electric vehicle, 22a Drive wheel, 22b Drive wheel, 24 Differential gear, 26 Drive shaft, 32 Motor, 34 Inverter, 36 Battery, 36a Voltage sensor, 36b Current sensor, 37 Battery ECU, 38a High voltage side power line, 38b Low voltage side power line, 39 Capacitor, 39a Voltage sensor, 40 Auxiliary battery, 40a Voltage sensor, 42 Auxiliary side power line, 46 Warning light, 48 DC / DC converter, 50 Step-up / Step-down converter, 70 ECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 87 Vehicle speed sensor, SMR System main relay, SMRB Positive side relay, SMRG Negative side relay.

Claims

1. A relay control system comprising: a first control device that operates using power from a battery and transmits a relay disconnection request; and a second control device that turns off the relay when it receives the disconnection request from the first control device via communication, The second control device shall turn off the relay if, when communication with the first control device is interrupted for a first hour, the battery voltage falls below a predetermined voltage. Relay control system.

2. A relay control system according to claim 1, The second control device, when communication with the first control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, turns off the relay if the interruption in communication with the first control device continues for a second hour, which is longer than the first hour. Relay control system.

3. A relay control system according to claim 2, A notification device that provides information. Equipped with, The second control device controls the notification device so as to notify that the relay should be turned off if the communication with the first control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, and the interruption in communication with the first control device continues for a second hour. Relay control system.

4. A relay control system according to claim 1, If the second control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, it sends a request to the first control device via the communication to send the shut-off request. If the communication with the first control device is still interrupted after a third hour has elapsed since the transmission of the request, it turns off the relay. Relay control system.

5. A relay control system according to claim 1, If the second control device is interrupted for a first hour and the battery voltage is below the predetermined voltage, and the interruption in communication with the first control device continues for a second hour longer than the first hour, the second control device sends a request to the first control device via communication to send the shut-off request, and if the communication with the first control device is still interrupted after a third hour has elapsed since the transmission of the request, the second control device turns off the relay. Relay control system.

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