control unit

Abstract

Suppresses back electromotive force. [Solution] The control unit 20 includes a switch 21 which is electrically connected to a power supply 11 on one side and to an equipment 12 on the other side and switches between on and off states according to the operating voltage, and a control device 22 which controls the operation of the switch 21 by controlling the operating voltage, and the control device 22 is capable of adjusting the rate of change of the operating voltage.

Description

Technical Field

[0004] ,

[0006] , , , , ,

[0005] , , , , ,

[0001] The present invention relates to a control unit.

Background Art

[0002] Conventionally, various techniques related to power supply from a power source to a device have been proposed. For example, Patent Document 1 discloses a technique related to control of power supply from a power source to a brake device as a technique for suppressing an increase in the size and cost of a system.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the power supply from a power source to a device may be controlled using a switch that is electrically connected to the power source on one side and to the device on the other side and whose on / off state is switched according to the operating voltage. In this case, a counter electromotive force may occur when the on / off state of the switch is switched. Here, in order to suppress damage caused by the counter electromotive force, it is conceivable to add an electronic component for suppressing the counter electromotive force. However, in that case, problems such as an increase in cost and compression of the mounting space may occur. Therefore, a new proposal for suppressing the counter electromotive force is desired.

[0005] Therefore, in view of such problems, an object of the present invention is to provide a control unit capable of suppressing a counter electromotive force.

Means for Solving the Problems

[0006] To solve the above problems, the control unit comprises a switch that is electrically connected to a power supply on one side and to the equipment on the other side, and whose on / off state switches according to the operating voltage, and a control device that controls the operation of the switch by controlling the operating voltage, wherein the control device is capable of adjusting the rate of change of the operating voltage. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress back electromotive force. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the general configuration of a control system according to an embodiment of the present invention. [Figure 2] This is a time chart showing an example of the changes in operating voltage and drain-source voltage for a comparative example. [Figure 3] This is a schematic diagram showing an example of the general configuration of the adjustment circuit of a control device according to an embodiment of the present invention. [Figure 4] This is a schematic diagram showing an example of the general configuration of the adjustment circuit of a control device according to an embodiment of the present invention. [Figure 5] This is a time chart showing an example of the transition between the operating voltage and the drain-source voltage according to an embodiment of the present invention. [Modes for carrying out the invention]

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0010] <Outline configuration of the control system> A schematic configuration of the control system 1 according to an embodiment of the present invention will be described.

[0011] Figure 1 is a schematic diagram showing the general configuration of control system 1. Control system 1 is mounted on a vehicle, for example. The following description will mainly focus on an example where control system 1 is mounted on a vehicle. However, control system 1 may also be mounted on devices other than vehicles (for example, other mobile devices, or various equipment fixed to the ground).

[0012] Control system 1 is a system for controlling the supply of power from a power source to various devices. As shown in Figure 1, control system 1 comprises a power source 11, multiple devices 12, multiple cables 13, a fuse 14, a relay 15, a DC-DC converter 16, and a control unit 20.

[0013] Power source 11 is, for example, an auxiliary battery in a vehicle. In this case, power source 11 is a battery with a voltage lower than the voltage of the power supplied to the vehicle's drive motor, and it stores the power supplied to each of the auxiliary devices 12.

[0014] Device 12 corresponds, for example, to an auxiliary device of a vehicle. In the example in Figure 1, four devices 12 are provided: devices 12a, 12b, 12c, and 12d. However, the number of devices 12 is not limited to the example in Figure 1; there may be one, two, three, or five or more.

[0015] For example, in a vehicle, the types of equipment 12 are classified from the perspective of functional safety. For example, a level indicating the degree to which each type of equipment 12 contributes to the functional safety of the vehicle (i.e., the degree to which equipment 12 affects the functional safety of the vehicle) is assigned to each type of equipment 12. For example, equipment 12 related to brakes and steering has a high level, while equipment 12 related to power windows and lamps has a low level. Note that the types of equipment 12, such as 12a, 12b, 12c, and 12d, are not particularly limited.

[0016] In control system 1, the DC-DC converter 16, the power supply 11, and each device 12 are electrically connected via the control unit 20, and the power supply from the DC-DC converter 16 or the power supply 11 to each device 12 is controlled by the control unit 20. Furthermore, the control unit 20 and each device are electrically connected via cables 13. In the example shown in Figure 1, six cables 13 are provided: cables 13a, 13b, 13c, 13d, 13e, and 13f. Specifically, the cables 13 are harnesses and have an inductance component. The electrical connection relationships in control system 1 will be described below.

[0017] The power supply 11 is electrically connected to the control unit 20 via a relay 15 and a cable 13e. The relay 15 and the cable 13e are connected in series with each other. As shown in Figure 1, when the relay 15 is ON, the power supply 11 can supply power to the control unit 20. On the other hand, when the relay 15 is OFF, the power supply 11 cannot supply power to the control unit 20.

[0018] The control unit 20 comprises a plurality of switches 21 and a control device 22. In the example shown in Figure 1, four switches 21 are provided: switches 21a, 21b, 21c, and 21d. Switching the on / off state of the switches 21 switches whether or not power is supplied at the location where the switches 21 are installed. When a switch 21 is in the on state, current can pass through the switch 21 (i.e., it is in a conductive state). On the other hand, when a switch 21 is in the off state, current cannot pass through the switch 21 (i.e., it is in a non-conductive state). The on / off state of each switch 21 is controlled by the control device 22.

[0019] Each switch 21 is a semiconductor switch such as a field effect transistor (FET). Specifically, each switch 21 includes a gate terminal G, a drain terminal D, and a source terminal S. The on / off state of each switch 21 is switched according to the operating voltage applied to the gate terminal G. For example, when an operating voltage is applied to the gate terminal G of the switch 21, the switch 21 turns on, and a current flows from the drain terminal D to the source terminal S of the switch 21. Such a current is also called a drain current. The control device 22 controls the operation of each switch 21 by controlling the operating voltage of each switch 21.

[0020] Note that hereinafter, an example of a fail-safe in which the switch 21 is in the on state when the operating voltage is applied and the switch 21 is in the off state when the operating voltage is not applied will be mainly described. However, the switch 21 may be in the off state when the operating voltage is applied and the switch 21 may be in the on state when the operating voltage is not applied.

[0021] One side of each switch 21 is electrically connected to the power supply 11, and the other side of each switch 21 is electrically connected to the device 12. Specifically, the source terminal S of the switch 21a and the drain terminals D of the switches 21b, 21c, and 21d are electrically connected to the power supply 11 via the cable 13e and the relay 15. The drain terminal D of the switch 21a is electrically connected to the device 12a via the cable 13a and the fuse 14 (i.e., a safety device that cuts off the current when the passing current becomes excessively high). The source terminal S of the switch 21b is electrically connected to the device 12b via the cable 13b. The source terminal S of the switch 21c is electrically connected to the device 12c via the cable 13c. The source terminal S of the switch 21d is electrically connected to the device 12d via the cable 13d.

[0022] By controlling the on / off state of switch 21a, the power supply from the DCDC converter 16 or power supply 11 to device 12a can be controlled. Similarly, by controlling the on / off state of switch 21b, the power supply from the DCDC converter 16 or power supply 11 to device 12b can be controlled. Furthermore, by controlling the on / off state of switch 21c, the power supply from the DCDC converter 16 or power supply 11 to device 12c can be controlled. Finally, by controlling the on / off state of switch 21d, the power supply from the DCDC converter 16 or power supply 11 to device 12d can be controlled.

[0023] A DC-DC converter 16 is electrically connected between cable 13a and fuse 14 via cable 13f. The DC-DC converter 16 is a voltage converter that converts voltage. The DC-DC converter 16 is electrically connected to a high-voltage battery (not shown) that stores power supplied to the vehicle's motor. When switch 21a is in the ON position, the DC-DC converter 16 is electrically connected to the power supply 11. For example, in this state, the DC-DC converter 16 can reduce the voltage of the power supplied from the high-voltage battery and supply that power to the power supply 11.

[0024] <Operation of the control unit> The operation of the control unit 20 according to an embodiment of the present invention will be described.

[0025] As described above, the control device 22 of the control unit 20 controls the operation of each switch 21 by controlling the operating voltage of each switch 21. Here, the control unit 20 switches the on / off state of each switch 21. For example, when the vehicle is running, basically all switches 21 are in the on state, and power can be supplied to all equipment 12 from the DC-DC converter 16 or power supply 11. However, in certain cases, the control device 22 switches the on / off state of some switches 21 from the on state to the off state.

[0026] The control device 22 switches the on / off state of some switches 21 from the on state to the off state, for example, when there is insufficient power in the control unit 20. For example, if the amount of power supplied from the DC-DC converter 16, or the amount of power stored in the power supply 11, is less than the amount of power required to operate all the equipment 12, the control device 22 determines that there is insufficient power in the control unit 20 and switches the on / off state of some switches 21 from the on state to the off state. In this case, the control device 22 prioritizes supplying power to equipment 12 that have a high level of contribution to the functional safety of the vehicle, compared to supplying power to equipment 12 with a low level of contribution. In other words, the control device 22 switches the on / off state of switches 21 that are electrically connected to equipment 12 with a low level of contribution from all the equipment 12, for example, from the on state to the off state. This helps to suppress a decrease in the functional safety of the vehicle.

[0027] Furthermore, the control device 22 switches the on / off state of some switches 21 from the on state to the off state when, for example, an abnormality occurs in the device on which the control unit 20 is installed. For example, if any abnormality occurs in the vehicle on which the control unit 20 is installed, the control device 22 switches the on / off state of switches 21 that are electrically connected to the equipment 12 associated with the abnormality from the on state to the off state. Also, for example, if an abnormality occurs that necessitates moving the vehicle to a safe distance and stopping it quickly, the control device 22 switches the on / off state of switches 21 that are electrically connected to the equipment 12 that have a low level of contribution to the functional safety of the vehicle from the on state to the off state. This allows the vehicle to be moved to a safe distance while ensuring a minimum level of functional safety.

[0028] Furthermore, the control device 22 switches the on / off state of the switch 21, which is electrically connected to the equipment 12, from the on state to the off state if, for example, an abnormality occurs in the equipment 12 or the cable 13 electrically connected to the equipment 12. For example, if an abnormality occurs in the equipment 12a, the control device 22 switches the on / off state of the switch 21a from the on state to the off state. Also, for example, if an abnormality (e.g., overheating) occurs in the cable 13a electrically connected to the equipment 12a, the control device 22 switches the on / off state of the switch 21a from the on state to the off state. This prevents malfunction or damage to the equipment 12 that may occur due to power being supplied to the malfunctioning equipment 12.

[0029] As described above, in certain cases, the on / off state of switch 21 is switched from the on state to the off state. As mentioned above, the switching of the on / off state of switch 21 is achieved by controlling the operating voltage of switch 21. The switching of the on / off state of switch 21 in a comparative example will be described below.

[0030] Figure 2 is a time chart showing an example of the changes in the operating voltage V_G and drain-source voltage V_DS for a comparative example. In Figure 2, the horizontal axis T represents time, and the vertical axis represents the operating voltage V_G and drain-source voltage V_DS, showing the changes in the operating voltage V_G and drain-source voltage V_DS.

[0031] The operating voltage V_G is the voltage applied to the gate terminal G and is also called the gate voltage. The drain-source voltage V_DS is the voltage between the drain terminal D and the source terminal S, and the drain current changes according to the drain-source voltage V_DS.

[0032] In the example in Figure 2, before time point T1, the operating voltage V_G is not applied, and switch 21 is in the off state. Then, at time point T1, for example, when the vehicle system starts up, the application of the operating voltage V_G begins, and the on / off state of switch 21 is switched from the off state to the on state. Subsequently, at time point T2, for example, the specific case described above occurs, the application of the operating voltage V_G ends, and the on / off state of switch 21 is switched from the on state to the off state.

[0033] In the comparative example shown in Figure 2, the operating voltage V_G changes instantaneously (i.e., rapidly) at time points T1 and T2. Specifically, at time point T1, the operating voltage V_G rises instantaneously. As a result, as shown in Figure 2, due to the inductance component of cable 13, the drain-source voltage V_DS rises sharply at time point T1 and then falls to a steady value, resulting in an overshoot phenomenon. Also, at time point T2, the operating voltage V_G drops instantaneously. As a result, as shown in Figure 2, due to the inductance component of cable 13, the drain-source voltage V_DS drops sharply at time point T2 and then rises to 0, resulting in an overshoot phenomenon. In the comparative example, at time points T1 and T2, when the on / off state of switch 21 is switched, the overshoot phenomenon occurs due to the instantaneous change in the operating voltage V_G, generating a large back electromotive force.

[0034] Therefore, in this embodiment, back electromotive force is suppressed by making the rate of change of the operating voltage V_G adjustable. Below, an example of a circuit provided to make the rate of change of the operating voltage V_G adjustable in this embodiment will be described.

[0035] Figures 3 and 4 are schematic diagrams showing an example of the general configuration of the adjustment circuit 23 of the control device 22. The adjustment circuit 23 shown in Figure 3 or Figure 4 is a schematic representation of a part of the control device 22's circuit and is a circuit that allows adjustment of the rate of change of the operating voltage V_G. Although Figures 3 and 4 only show an adjustment circuit 23 provided for one switch 21, the adjustment circuit 23 can be provided for, for example, all of the switches 21. Furthermore, the adjustment circuit 23 may be provided for only some of the switches 21.

[0036] In the example shown in Figure 3, the adjustment circuit 23 includes a power supply 23a, a variable resistor 23b, and a switch 23c. The power supply 23a, variable resistor 23b, and switch 23c are connected in series in that order. The terminal of switch 23c opposite to that of the variable resistor 23b is connected to the gate terminal G of switch 21. As shown in Figure 3, when switch 23c is ON, the power supply 23a is electrically connected to the gate terminal G of switch 21 via the variable resistor 23b, and an operating voltage V_G is applied to the gate terminal G. On the other hand, when switch 23c is OFF, the electrical connection between the power supply 23a and the gate terminal G of switch 21 is interrupted, and no operating voltage V_G is applied to the gate terminal G.

[0037] The variable resistor 23b is a resistor whose resistance value can be changed. The control device 22 can adjust the resistance value of the variable resistor 23b. By adjusting the resistance value of the variable resistor 23b, the control device 22 can adjust the rate at which the operating voltage V_G changes. Specifically, the control device 22 can adjust the rate at which the operating voltage V_G changes by adjusting the resistance value of the variable resistor 23b.

[0038] In the example shown in Figure 4, the adjustment circuit 23 includes a variable power supply 23d and a switch 23c. The variable power supply 23d and the switch 23c are connected in series in that order. The terminal of the switch 23c opposite to the variable power supply 23d is connected to the gate terminal G of the switch 21. As shown in Figure 3, when the switch 23c is ON, the variable power supply 23d is electrically connected to the gate terminal G of the switch 21, and an operating voltage V_G is applied to the gate terminal G. On the other hand, when the switch 23c is OFF, the electrical connection between the variable power supply 23d and the gate terminal G of the switch 21 is interrupted, and no operating voltage V_G is applied to the gate terminal G.

[0039] The variable power supply 23d is a power supply whose voltage can be changed. The control device 22 can adjust the voltage of the variable power supply 23d. By adjusting the voltage of the variable power supply 23d, the control device 22 can adjust the rate at which the operating voltage V_G changes. Specifically, when the control device 22 changes the operating voltage V_G, it can adjust the rate at which the operating voltage V_G changes by changing the voltage of the variable power supply 23d over time.

[0040] Figure 5 is a time chart showing an example of the changes in the operating voltage V_G and drain-source voltage V_DS according to this embodiment. In Figure 5, as in Figure 2, the horizontal axis T represents time, and the vertical axis represents the operating voltage V_G and drain-source voltage V_DS, showing the changes in the operating voltage V_G and drain-source voltage V_DS.

[0041] In Figure 5, the changes in the operating voltage V_G and drain-source voltage V_DS in the comparative example of Figure 2 described above are shown by the dashed lines.

[0042] In the example in Figure 5, similar to Figure 2, before time point T1, no operating voltage V_G is applied, and switch 21 is in the off state. Then, at time point T1, the operating voltage V_G begins to rise, and the on / off state of switch 21 is switched from the off state to the on state. Subsequently, at time point T2, the operating voltage V_G begins to fall, and the on / off state of switch 21 is switched from the on state to the off state.

[0043] As described above, in this embodiment, the control device 22 can adjust the rate of change of the operating voltage V_G. Specifically, the control device 22 adjusts the rate of change of the operating voltage V_G so that it does not change instantaneously but changes gradually over time. Therefore, as shown in Figure 5, at time points T1 and T2, the operating voltage V_G changes gradually over time.

[0044] Specifically, from time point T1 onward, the operating voltage V_G gradually increases over time. As a result, as shown in Figure 5, an overshoot phenomenon occurs in which the drain-source voltage V_DS rises sharply at time point T1 and then falls to a steady value. However, the amount of increase in the drain-source voltage V_DS during this overshoot phenomenon is smaller than that of the comparative example in Figure 2. Furthermore, from time point T2 onward, the operating voltage V_G gradually decreases over time. As a result, as shown in Figure 2, an overshoot phenomenon occurs in which the drain-source voltage V_DS drops sharply at time point T2 and then rises to 0. However, the amount of decrease in the drain-source voltage V_DS during this overshoot phenomenon is smaller than that of the comparative example in Figure 2. Thus, in this embodiment, the amount of change in the drain-source voltage V_DS can be reduced at time points T1 and T2 when the on / off state of the switch 21 is switched, thereby suppressing back electromotive force.

[0045] As described above, in this embodiment, when switching the on / off state of switch 21, the operating voltage V_G gradually changes over time. Here, the time taken from the start to the end of the change in the operating voltage V_G is set according to, for example, the type of equipment 12 electrically connected to the switch 21 that is to be switched on / off. For example, the allowable time for stopping the power supply to equipment 12 differs depending on the type of equipment 12. Therefore, it is preferable for the control device 22 to adjust the rate of change of the operating voltage V_G of the switch 21 electrically connected to the equipment 12 according to the type of equipment 12. For example, it is preferable for the control device 22 to adjust the rate of change of the operating voltage V_G of the switch 21 electrically connected to the equipment 12 so that the time taken to switch the on / off state of switch 21 from the on state to the off state is less than or equal to the allowable time set for each piece of equipment 12.

[0046] <Effects of the control unit> The effects of the control unit 20 according to an embodiment of the present invention will be described below.

[0047] The control unit 20 includes a switch 21, which is electrically connected to the power supply 11 on one side and to the equipment 12 on the other side, and whose on / off state switches according to the operating voltage V_G, and a control device 22 that controls the operation of the switch 21 by controlling the operating voltage V_G, and the control device 22 is capable of adjusting the rate of change of the operating voltage V_G. As a result, the rate of change of the operating voltage V_G can be adjusted so that the operating voltage V_G does not change instantaneously but changes gradually over time. Therefore, the amount of change in the drain-source voltage V_DS at the time the on / off state of the switch 21 switches can be reduced, and thus back electromotive force can be suppressed.

[0048] Furthermore, according to this embodiment, back electromotive force can be suppressed while minimizing the need to add electronic components to suppress back electromotive force. Therefore, back electromotive force can be suppressed while avoiding problems such as increased costs and reduced mounting space caused by the addition of electronic components.

[0049] Preferably, in the control unit 20, the control device 22 adjusts the rate of change of the operating voltage V_G of the switch 21 electrically connected to the equipment 12, according to the type of equipment 12. This makes it possible to, for example, keep the time it takes to switch the on / off state of the switch 21 from the on state to the off state below the allowable time set for each piece of equipment 12.

[0050] Preferably, the control unit 20 includes a plurality of switches 21, each connected to a plurality of devices 12, and the control device 22 switches the on / off state of some of the switches 21 from the on state to the off state when there is insufficient power in the control unit 20. This can suppress, for example, a decrease in the functional safety of the vehicle.

[0051] Preferably, the control unit 20 includes a plurality of switches 21, each connected to a plurality of devices 12, and the control device 22 switches the on / off state of some of the switches 21 from the on state to the off state when an abnormality occurs in the device on which the control unit 20 is mounted. This allows, for example, the vehicle to be moved to a safe location while ensuring a minimum level of functional safety.

[0052] Preferably, in the control unit 20, the control device 22 switches the on / off state of the switch 21 electrically connected to the equipment 12 from the on state to the off state when an abnormality occurs in the equipment 12 or the cable 13 electrically connected to the equipment 12. This prevents malfunction or damage to the equipment 12 that may occur due to power being supplied to the malfunctioning equipment 12.

[0053] Preferably, in the control unit 20, the control device 22 can adjust the rate of change of the operating voltage V_G when switching the on / off state of the switch 21 from the on state to the off state (for example, the rate of change in the decrease of the operating voltage V_G starting from time T2 in the example of Figure 5). This makes it possible to suppress the back electromotive force when switching the on / off state of the switch 21 from the on state to the off state.

[0054] Preferably, in the control unit 20, the control device 22 can adjust the rate of change of the operating voltage V_G when switching the on / off state of the switch 21 from the off state to the on state (for example, the rate of change in the rise of the operating voltage V_G starting from time T1 in the example of Figure 5). This makes it possible to suppress the back electromotive force when switching the on / off state of the switch 21 from the off state to the on state.

[0055] In the example shown in Figure 5 above, an example was described in which both the rate of change of the operating voltage V_G when switching the on / off state of switch 21 from the on state to the off state, and the rate of change of the operating voltage V_G when switching the on / off state of switch 21 from the off state to the on state, are adjusted. However, the control device 22 may only be able to adjust one of the rates of change of the operating voltage V_G when switching the on / off state of switch 21 from the on state to the off state, or the rate of change of the operating voltage V_G when switching the on / off state of switch 21 from the off state to the on state.

[0056] Preferred embodiments of the present invention have been described above with reference to the attached drawings. However, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications or alterations within the scope of the claims also fall within the technical scope of the present invention. [Explanation of symbols]

[0057] 1. Control System 11 Power supply 12 Equipment 12a equipment 12b equipment 12c equipment 12d equipment 13 Cables 13a cable 13b cable 13c cable 13d cable 13e cable 13f cable 14 fuses 15 Relay 16 DC-DC converters 20 Control Units 21 switches 21a switch 21b switch 21c switch 21d switch 22 Control device 23 Adjustment circuit 23a power supply 23b Variable resistor 23c switch 23d Variable Power Supply D drain terminal G gate terminal S Source terminal V_DS Drain-source voltage V_G Operating Voltage

Claims

1. One side is electrically connected to the power supply (11), and the other side is electrically connected to the equipment (12), and the switch (21) switches between on and off states according to the operating voltage (V_G), A control device (22) controls the operation of the switch (21) by controlling the operating voltage (V_G), Equipped with, The control device (22) is capable of adjusting the rate of change of the operating voltage (V_G). Control unit.

2. The control device (22) adjusts the rate of change of the operating voltage (V_G) of the switch (21) that is electrically connected to the equipment (12), according to the type of equipment (12). The control unit according to claim 1.

3. The control unit (20) comprises a plurality of switches (21) each connected to a plurality of the devices (12), The control device (22) switches the on / off state of some of the switches (21) from the on state to the off state when there is insufficient power in the control unit (20). The control unit according to claim 1.

4. The control unit (20) comprises a plurality of switches (21) each connected to a plurality of the devices (12), The control device (22) switches the on / off state of some of the switches (21) from the on state to the off state when an abnormality occurs in the device on which the control unit (20) is mounted. The control unit according to claim 1.

5. The control device (22) switches the on / off state of the switch (21) electrically connected to the device (12) from the on state to the off state when an abnormality occurs in the device (12) or the cable (13) electrically connected to the device (12). The control unit according to claim 1.

6. The control device (22) is capable of adjusting the rate of change of the operating voltage (V_G) when switching the on / off state of the switch (21) from the on state to the off state. A control unit according to any one of claims 1 to 5.

7. The control device (22) is capable of adjusting the rate of change of the operating voltage (V_G) when switching the on / off state of the switch (21) from the off state to the on state. A control unit according to any one of claims 1 to 5.

Images