Power control unit

Abstract

To provide a power control device that can charge regenerative power. [Solution] The power control device according to the embodiment comprises a first system, a second system, an inter-system switch, and a controller. The first system is connected to a first load with a main power supply. The second system is connected to a second load with a backup power supply via a charge / discharge control unit. The inter-system switch connects the first system and the second system. The controller normally turns on the inter-system switch and controls the charge / discharge control unit so that it does not perform charging or discharging. When the controller detects the generation of regenerative power from the second load, it controls the charge / discharge control unit so that the regenerative power is supplied to the backup power supply.

Description

[Technical Field]

[0001] The present invention relates to a power supply control device. [Background Art]

[0002] Conventionally, a redundant power supply system is known that includes: a first system in which a main power supply is connected to a first load; a second system in which a backup power supply is connected to a second load; and an inter-system switch connecting the first system and the second system (see, for example, Patent Document 1). Patent Document 1 discloses a technology for continuing the traveling of a vehicle by supplying power from a backup power supply to a load when an abnormality occurs in the main power supply. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2023-11357 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, although Patent Document 1 discloses a technology related to power supply to a backup target load, it does not assume that regenerative power is generated in the backup target load. Therefore, when regenerative power is generated in the load, the generated regenerative power is not charged to the backup power supply.

[0005] The present invention has been made in view of the foregoing, and an object of the present invention is to provide a power supply control device capable of charging regenerative power generated in a backup target load to a backup power supply. [Means for Solving the Problem]

[0006] To solve the above-mentioned problems and achieve the objective, the power control device according to the present invention comprises a first system, a second system, an inter-system switch, and a controller. The first system has a main power supply connected to a first load. The second system has a backup power supply connected to a second load via a charge / discharge control unit. The inter-system switch connects the first system and the second system. The controller normally turns on the inter-system switch and controls the charge / discharge control unit so that it does not perform charging or discharging. When the controller detects the generation of regenerative power from the second load, it controls the charge / discharge control unit so that the regenerative power is supplied to the backup power supply. [Effects of the Invention]

[0007] According to the present invention, when regenerative power is generated in the second load, which is the load to be backed up, the charge / discharge control unit is controlled so that the regenerative power is supplied to the backup power supply, thereby enabling the backup power supply to be charged with the regenerative power generated in the second load. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an explanatory diagram of the configuration and operation of the power control device according to the embodiment. [Figure 2] Figure 2 is an explanatory diagram of the configuration and operation of the power control device according to the embodiment. [Figure 3] Figure 3 is an explanatory diagram of the configuration and operation of the power control device according to the embodiment. [Figure 4] Figure 4 is an explanatory diagram of the configuration and operation of the power control device according to the embodiment. [Figure 5] Figure 5 illustrates the operation of the power control device when regenerative power is generated. [Figure 6] Figure 6 illustrates the operation of the power control device when regenerative power is generated. [Figure 7] Figure 7 illustrates the operation of the power control device when regenerative power is generated. [Figure 8] Figure 8 illustrates the operation of the power control device when regenerative power is generated. [Figure 9] Figure 9 is a flowchart showing the processing procedure for the regenerative power operation of the power control device according to the embodiment. [Figure 10] Figure 10 is an explanatory diagram of the configuration and operation of a modified power control device. [Figure 11] Figure 11 is an explanatory diagram of the configuration and operation of a modified power control device. [Modes for carrying out the invention]

[0009] The power control device according to the embodiment will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the embodiments shown below. The following description will focus on the case where the vehicle on which the power control device according to the embodiment is installed is an electric vehicle or a hybrid vehicle.

[0010] The vehicle on which the power control device according to this embodiment is installed may be an engine-powered vehicle that runs on an internal combustion engine. The power control device according to this embodiment is a device that is installed in a vehicle equipped with an autonomous driving function and supplies power to the load. Furthermore, although the following example shows the power control device backing up the power supply to the load used for driving during autonomous driving, it may also be configured to back up the power supply to the load used for driving during normal driving (manual driving).

[0011] [Configuration of the power control unit] The configuration and operation of the power control device 1 according to the embodiment will be described with reference to Figures 1 to 4. Figures 1 to 4 are explanatory diagrams of the configuration and operation of the power control device 1 according to the embodiment. As shown in Figure 1, the power control device 1 according to the embodiment is connected to the main power supply 10, the first load 101, the general load 102, the second load 103, and the automatic operation control device 100.

[0012] A power control device 1 includes a first system 110 and a second system 120. The first system 110 is a power supply system that supplies power from a main power supply 10 to a first load 101 and a general load 102. The second system 120 is a power supply system that supplies power from a backup power supply 20, which will be described later, to a second load 103. Note that the main power supply 10 is a first power supply, and the backup power supply 20 is a second power supply.

[0013] The first load 101 is a load used for traveling of a vehicle (running, turning, stopping, etc.), and includes a load for automatic driving. The first load 101 includes, for example, a steering motor that operates during automatic driving, an electric brake device, an in-vehicle camera, and the like. The general load 102 is a load that is not directly involved in automatic driving, and includes a display, an air conditioner, an audio device, a video device, various lights, and the like.

[0014] The second load 103 is a load used for traveling of a vehicle (running, turning, stopping, etc.), and has a part of the automatic driving functions included in the first load 101. The second load 103 includes, for example, devices minimum required for FOP (Fail Operation, evacuation travel control) such as a steering motor, an electric brake device, and a radar. The first load 101, the general load 102, and the second load 103 operate by power supplied from the power control device 1.

[0015] An automatic driving control device 100 is a control device used for travel control of a vehicle, and is a device that controls travel operations such as automatic driving control of the vehicle by operating loads that control traveling of the vehicle such as the first load 101 and the second load 103. The automatic driving control device 100 can implement FOP by the second load 103 when a power failure such as a ground fault occurs in the first system 110 during automatic driving of the vehicle. Further, the automatic driving control device 100 can implement FOP by the first load 101 when a power failure such as a ground fault occurs in the second system 120.

[0016] Specifically, when a power failure occurs during automatic driving, the automatic driving control device 100 performs evacuation traveling control of the vehicle, causes the vehicle to travel to a safe location and stop. When the automatic driving control device 100 normally completes evacuation traveling, it transmits an evacuation traveling completion notification indicating this to the power supply control device 1.

[0017] The main power supply 10 includes a DC / DC converter (hereinafter referred to as "DC / DC 11") and a lead battery (hereinafter referred to as "PbB 12"). Note that the battery of the main power supply 10 may be any secondary battery other than PbB 12.

[0018] The DC / DC 11 is connected to the high-voltage battery 210. The DC / DC 11 steps down the voltage of the high-voltage battery 210 and outputs the stepped-down voltage to the first system 110. The high-voltage battery 210 is a battery having a higher voltage than PbB 12, and is a battery for driving a vehicle mounted on an electric vehicle or a hybrid vehicle. Specifically, the high-voltage battery 210 is connected to the traveling motor 300 and supplies electric power to the traveling motor 300. In addition, regenerative electric power generated by the traveling motor 300 is supplied to the high-voltage battery 210, and the high-voltage battery 210 is charged.

[0019] Note that when the main power supply 10 is mounted on a vehicle provided with an engine such as an engine vehicle or a hybrid vehicle, an alternator (generator) is provided instead of or in addition to the DC / DC 11. The DC / DC 11 charges PbB 12, supplies power to the first load 101 and the general load 102, supplies power to the second load 103, and charges the backup power supply 20. The alternator supplies the generated electric power to the first system 110 such as the main power supply 10, whereby charging of the main power supply 10 and power supply to each load are performed.

[0020] The power control device 1 comprises a backup power supply 20, an inter-system switch 41, a system relay 42, a charge / discharge control unit 5, a controller 3, a power failure detection circuit 4, a first voltage sensor 51, a second voltage sensor 52, a ground connection switch 61, and a diode 62. The backup power supply 20 is a backup power supply for when the main power supply 10 is unable to supply power. The backup power supply 20 is equipped with a lithium-ion battery (hereinafter referred to as "LiB21"). The battery of the backup power supply 20 may be any secondary battery other than LiB21.

[0021] The inter-system switch 41 is installed in the inter-system line 130 that connects the first system 110 and the second system 120. The inter-system switch 41 is a switch that can connect and disconnect the first system 110 and the second system 120.

[0022] In this embodiment, electrically connecting the first system 110 and the second system 120 by the inter-system switch 41 is referred to as conducting the inter-system switch 41 or turning on the inter-system switch 41.

[0023] Furthermore, in this embodiment, disconnecting the electrical connection between the first system 110 and the second system 120 using the inter-system switch 41 is referred to as shutting off the inter-system switch 41 or turning off the inter-system switch 41.

[0024] The system relay 42 is a switch that can connect and disconnect the backup power supply 20 to the second system 120. The system relay 42 is always connected when the power supply (vehicle power supply, IG, power supply of power control device 1, etc.) is ON, and is always disconnected when it is OFF. In this embodiment, electrically connecting the backup power supply 20 and the second system 120 by the system relay 42 is referred to as conducting the system relay 42 or turning on the system relay 42.

[0025] In this embodiment, disconnecting the electrical connection between the backup power supply 20 and the second system 120 using the system relay 42 is referred to as shutting off the system relay 42 or turning off the system relay 42.

[0026] The charge / discharge control unit 5 controls the discharge from the backup power supply 20 and the charging of the backup power supply 20. Specifically, the charge / discharge control unit 5 includes a battery switch 43 and a DC / DC converter (DC / DC) 23. The battery switch 43 is a switch that can connect and disconnect the system relay 42 and the second system 120. In other words, the battery switch 43 is a switch that connects the backup power supply 20 to the second system 120. The DC / DC converter 23 is connected in parallel with the battery switch 43 and is normally inactive, but operates during charging to adjust the voltage input to the LiB 21. Specifically, the controller 3, described later, operates the DC / DC converter 23 to charge the backup power supply 20 when the State of Charge (SOC) of the backup power supply 20 decreases. Also, since the DC / DC converter 23 does not supply current when it is not operating, when the battery switch 43 is off and the DC / DC converter 23 is not operating, the charge / discharge control unit 5 enters a cutoff state where no current flows. While DC / DC23 is basically a unidirectional DC-DC converter capable of supplying current only in the direction of charging the backup power supply 20, it may also be a bidirectional DC-DC converter capable of supplying current in both directions, including the direction of discharging from the backup power supply 20.

[0027] The first voltage sensor 51 is provided in the first system 110. The first voltage sensor 51 detects the voltage of the first system 110 and outputs the detection result to the controller 3. The second voltage sensor 52 is provided in the second system 120. The second voltage sensor 52 detects the voltage of the second system 120 and outputs the detection result to the controller 3.

[0028] The ground connection switch 61 is a switch that can connect and disconnect the second system 120 and ground. Specifically, one end of the ground connection switch 61 is connected to the second system 120, and the other end is connected to ground via the diode 62.

[0029] Diode 62 has its anode connected to the ground connection switch 61 and its cathode connected to ground. Although Figure 1 shows an example where only one diode 62 is connected, in reality, a number of diodes of the same orientation that can drop the voltage by the amount of the second threshold voltage Th2 (see Figure 5) described later are connected in series.

[0030] Controller 3 includes a microcomputer with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various circuits. Controller 3 may also be composed of hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0031] Controller 3 controls the operation of power control device 1 by having the CPU execute a program stored in ROM, using RAM as a working area. Controller 3 controls the power failure detection circuit 4, inter-system switch 41, system relay 42, battery switch 43, DC / DC 11, 23 and ground connection switch 61.

[0032] Furthermore, the controller 3 obtains a status value indicating the charge status of the backup power supply 20 via the status monitoring line 22. The status value indicating the charge status of the backup power supply 20 is, for example, the SOC of the LiB21.

[0033] LiB21 has maximum charge when its SOC is 100%. LiB21 has no charge when its SOC is 0%. Controller 3 monitors the charge level of the backup power supply 20 based on the SOC of LiB21.

[0034] Furthermore, the controller 3 detects a failure of the main power supply 10 or the backup power supply 20 based on the detection results input from the first voltage sensor 51 and the second voltage sensor 52. For example, the controller 3 detects a failure of the first system 110 or the second system 120. A failure of the main power supply 10 includes short circuits such as ground faults in the first system 110, open circuits in the first system 110, and overvoltage or undervoltage abnormalities due to abnormalities in upstream components that supply power such as the main power supply 10. A failure of the backup power supply 20 includes short circuits such as ground faults in the second system 120 and open circuits in the second system 120. When the controller 3 detects a failure of the first system 110 or the second system 120, it notifies the automatic operation control device 100 of this fact.

[0035] Specifically, if controller 3 detects a failure of the main power supply 10 or the backup power supply 20, it outputs an automatic operation prohibition signal to the automatic operation control device 100 indicating that automatic operation is not possible. If controller 3 does not detect a failure of the main power supply 10 or the backup power supply 20, it outputs an automatic operation permission signal to the automatic operation control device 100 indicating that automatic operation is possible.

[0036] Furthermore, if the controller 3 detects a failure of the main power supply 10 or the backup power supply 20, it stores diagnostic information indicating this in the non-volatile memory. Then, at the next startup, if the diagnostic information is stored in the non-volatile memory, the controller 3 prohibits automatic operation by the automatic operation control device 100.

[0037] Specifically, the controller 3 prohibits automatic driving by the automatic driving control device 100 by outputting an automatic driving prohibition signal to the automatic driving control device 100 indicating that automatic driving is not possible. This prevents the power control device 1 from mistakenly performing automatic driving by the automatic driving control device 100 even if the failure of the main power supply 10 or backup power supply 20 has not been resolved at the next startup after the emergency run is completed.

[0038] Furthermore, the controller 3 detects the generation of regenerative power in the second load 103 based on the detection result of the second voltage sensor 52. Specifically, the controller 3 determines that regenerative power is being generated in the second load 103 when it detects a voltage increase by the second voltage sensor 52 while power is being supplied to the second load 103 from the main power supply 10, that is, when a voltage higher than the voltage generated when the second load 103 is in a normal operating state (including a standby state where the load is not actually moving) is generated. Regenerative power is generated, for example, when the steering motor is driven by an external force (manual operation by the driver). Regenerative power is also generated when motors that drive door windows, electric doors, or wipers are driven by an external force, in addition to the steering motor. In other words, the regenerative power in this disclosure is the regenerative power generated in loads other than the driving motor 300, such as the first load 101 or the second load 103. As will be described in detail later, in this disclosure, the regenerative power generated by loads other than the driving motor 300 is controlled to charge the main power supply 10 or the backup power supply 20. The regenerative power generated by the driving motor 300 is supplied to the high-voltage battery 210 via a device different from the power control device 1. Thus, in this disclosure, the power control device 1 can charge the main power supply 10 or the backup power supply 20 with regenerative power generated by loads other than the driving motor 300. In order to determine the operating state of the second load 103 in more detail, the control state of each load (whether it is in standby mode or driving mode) may be obtained from a control device (not shown, such as a steering control device) that controls each load, and it may be determined that regeneration is occurring when a voltage rise is detected while in standby mode. Alternatively, the control device that controls each load may be configured to obtain the state of each load as being in a regenerative state.

[0039] The generation of regenerative power may also be detected by, for example, a current sensor. For example, the current sensor may be placed in place of or alongside the second voltage sensor 52, and may detect the current value and direction of the current flowing through the path of the second system 120. For example, the controller 3 detects the generation of regenerative power when the current sensor detects that current is flowing from the second load 103.

[0040] Furthermore, although this disclosure uses the case where regenerative power is generated at the second load 103 as an example, regenerative power can also be generated at the first load 101. The generation of regenerative power at the first load 101 can be detected in the same way as described for the second load 103, and can be detected, for example, based on the detection result of the first voltage sensor 51.

[0041] When the controller 3 detects the generation of regenerative power, it controls the charge / discharge control unit 5 so that the regenerative power is supplied to the backup power supply 20. Specifically, the controller 3 performs the operations shown in Figures 5 to 8, which will be described later, based on the voltage value of the regenerative power (the value detected by the second voltage sensor 52). In this way, in this disclosure, when regenerative power is generated at the second load 103 (or the first load 101), the controller 3 controls the charge / discharge control unit 5 so that the regenerative power is supplied to the backup power supply 20, thereby charging the backup power supply 20 with regenerative power.

[0042] The power failure detection circuit 4 is a hardware circuit that detects power failures in the first system 110 and the second system 120. For example, the power failure detection circuit 4 has a comparator. In this case, the comparator compares the voltage detected by the first voltage sensor 51 or the second voltage sensor 52 with a threshold reference voltage and detects when the voltage exceeds the reference voltage. The power failure detection circuit 4 detects power failures in an overvoltage state where the voltage detected by the voltage sensor is above the overvoltage threshold, and in an undervoltage state where the voltage is below the undervoltage threshold.

[0043] Next, the basic operation of the power control device 1 will be explained using Figures 1 to 4.

[0044] [Normal operation of the power control device] First, let's explain the normal operation using Figure 1. When there is no failure in the main power supply 10 and backup power supply 20, the controller 3 controls the inter-system switch 41 and the battery switch 43 as shown in Figure 1. Specifically, the controller 3 shuts off the battery switch 43 and conducts the inter-system switch 41. As a result, power is supplied from the main power supply 10 to the first load 101, the general load 102, and the second load 103. The controller 3 also turns on the system relay 42 when the system starts up (IG is on) and turns off the system relay 42 when the system shuts down (IG is off). When there is no failure in the main power supply 10 and backup power supply 20, the controller 3 outputs an automatic operation permission signal to the automatic operation control device 100.

[0045] [Operation of the power control unit in the event of a power failure] Next, the operation of the power control device 1 when a power failure occurs will be explained with reference to Figures 2 to 4. The controller 3 detects the occurrence of a power failure by comparing the parameters related to the failure of the first system 110 or the second system 120 with a threshold value and determining that the parameters have exceeded the threshold value.

[0046] This section describes the case where the parameter related to the failure of the main power supply 10 is the voltage of the first system 110, and the parameter related to the failure of the backup power supply 20 is the voltage of the second system 120. In the following, the voltage of the first system 110 detected by the first voltage sensor 51 will be referred to as the first system voltage V1. The voltage of the second system 120 detected by the second voltage sensor 52 will be referred to as the second system voltage V2.

[0047] The parameter related to the failure of the main power supply 10 may be the current flowing through the first system 110 or the current flowing through the second system 120. In this case, the power control device 1 includes a current sensor for detecting the current flowing through the first system 110 and a current sensor for detecting the current flowing through the second system 120. The controller 3 then detects the occurrence of a ground fault when the current flowing through the first system 110 or the current flowing through the second system 120 exceeds an overcurrent threshold.

[0048] For example, if a ground fault 200 occurs in the first system 110 (see Figure 3), or if a ground fault 201 occurs in the second system 120 (see Figure 4), the power control device 1 will allow an overcurrent to flow towards the ground fault point. As a result, the voltages of the first system V1 and the second system V2 will fall below the ground fault threshold. The ground fault threshold is, for example, the same value as the low voltage threshold used in the power failure detection circuit 4 described above. Note that the ground fault threshold may be a different value from the low voltage threshold.

[0049] When the voltages of the first system V1 and the second system V2 fall below the ground fault threshold, the controller 3 tentatively determines that a ground fault 200 or ground fault 201 has occurred in the first system 110 or the second system 120. Subsequently, the controller 3 outputs an automatic operation prohibition signal to the automatic operation control device 100.

[0050] Then, when controller 3 tentatively determines that ground fault 200 or ground fault 201 has occurred, it turns on battery switch 43 and then turns off inter-system switch 41. As a result, the connection between the first system 110 and the second system 120 is severed, so power is supplied from the main power supply 10 to the first system 110 and from the backup power supply 20 to the second system 120. Hereafter, the tripping of the inter-system switch 41 based on the result of the tentative determination will also be referred to as pre-tripping.

[0051] Furthermore, the controller 3 can also tentatively determine that a ground fault has occurred in either the first system 110 or the second system 120 if at least one of the first system voltage V1 and the second system voltage V2 falls below the ground fault threshold.

[0052] This preliminary determination may be performed by the power failure detection circuit 4 equipped with a comparator, or by both the controller 3 and the power failure detection circuit 4. In the latter case, the comparator compares the second system voltage V2 with a low voltage threshold. When the detected voltage falls below the low voltage threshold, the comparator outputs a failure detection signal indicating a preliminary determination, thereby turning off the inter-system switch 41 and turning on the battery switch 43.

[0053] Next, the controller 3 makes a preliminary determination that a ground fault has occurred in either the first system 110 or the second system 120, and then makes a final determination to determine which system has the ground fault. When the controller 3 turns off the inter-system switch 41 and turns on the battery switch 43, the system voltage of the system without a ground fault returns to a normal state, while the system voltage of the system with a ground fault continues to decrease.

[0054] Controller 3 determines that a ground fault 200 has occurred in the first system 110 if, after pre-tripping, the voltage V1 of the first system remains below the ground fault threshold for a predetermined period of time, and the voltage V2 of the second system recovers to a normal threshold (higher than the ground fault threshold) for a predetermined period of time. In other words, Controller 3 determines that the second system 120 is normal. The predetermined period here is, for example, 100 ms. However, the predetermined period is not limited to 100 ms. Also, the normal threshold is a value higher than the ground fault threshold.

[0055] When controller 3 determines that a ground fault 200 has occurred in the first system 110, it continues the switch control state from the provisional determination (inter-system switch 41 off, battery switch 43 on), as shown in Figure 3, thereby performing fail-safe control to supply power from the backup power supply 20 to the second load 103, and notifies the automatic driving control device 100 of this. As a result, the automatic driving control device 100 can operate the second load 103 with the power supplied from the backup power supply 20, allowing the vehicle to move to a safe location and stop. Fail-safe control may also include the interruption of the inter-system switch 41, the conduction of the battery switch 43 based on the provisional determination, and notification to the automatic driving control device 100 when the determination is finalized.

[0056] Furthermore, after pre-tripping, the controller 3 determines that a ground fault 201 has occurred in the second system 120 if the first system voltage V1 recovers to above the normal threshold for a predetermined period of time or longer, and the second system voltage V2 remains below the ground fault threshold for a predetermined period of time or longer. In other words, the controller 3 determines that the first system 110 is normal.

[0057] If the controller 3 determines that a ground fault 201 has occurred in the second system 120, it performs fail-safe control, as shown in Figure 4, by turning off the battery switch 43, which was turned on in the preliminary determination, and supplying power from the main power supply 10 to the first load 101 and the general load 102. The controller 3 then notifies the automatic driving control device 100 of this. As a result, the automatic driving control device 100 operates the first load 101 with the power supplied from the main power supply 10, and drives the vehicle to a safe location and stops.

[0058] Furthermore, if, after pre-cutting, both the first system voltage V1 and the second system voltage V2 recover to above the normal threshold for a predetermined period of time or longer, the controller 3 determines that it was a transient voltage drop and that no ground faults 200 and 201 occurred. In other words, the controller 3 determines that both the first system 110 and the second system 120 are normal.

[0059] In this case, the controller 3 performs a recovery process. The recovery process involves turning on the inter-system switch 41 from the pre-shutdown state shown in Figure 2, then turning off the battery switch 43, and returning to the normal operation state shown in Figure 1. This allows the controller 3 to suppress a decrease in the amount of stored energy in the backup power supply 20.

[0060] In the above, a ground fault was used as an example of a power failure, but a power failure may also be an overvoltage (short circuit). If the power failure is an overvoltage, the controller 3 will make a preliminary determination that an overvoltage has occurred in the first system 110 or the second system 120 and perform a pre-shutdown if at least one of the first system voltage V1 and the second system voltage V2 exceeds the overvoltage threshold. After the pre-shutdown, the controller 3 will make a final determination that an overvoltage (short circuit) has occurred in the first system 110 if the first system voltage V1 remains above the overvoltage threshold for a predetermined period of time and the second system voltage V2 remains below the overvoltage threshold for a predetermined period of time. In other words, the controller 3 will determine that the second system 120 is normal.

[0061] As described above, Figures 1 to 4 illustrate the power supply operation from the power source to each load under normal conditions and in the event of a power failure. In this disclosure, when regenerative power is generated at the second load 103, the regenerative power can be used to charge the main power source 10 or the backup power source 20. This point will be explained using Figures 5 to 8.

[0062] [Operation of the power control device when regenerative power is generated] Figures 5 to 8 illustrate the operation of the power control device 1 when regenerative power is generated. Figures 5 to 8 illustrate the case when regenerative power is generated at the second load 103 while the vehicle is in a normal state (automatic operation or vehicle startup state without automatic operation) where the power failure described in Figures 2 to 4 has not occurred. Figure 5 shows the case where the regenerative power voltage V2 (second system voltage V2) is greater than or equal to the first threshold Th1, less than the second threshold Th2, and greater than or equal to the voltage of LiB21. Figure 6 shows the case where the regenerative power voltage V2 is greater than or equal to the first threshold Th1, less than the second threshold Th2, and less than the voltage of LiB21. Figure 7 shows the case where the regenerative power voltage V2 is less than the first threshold Th1. Figure 8 shows the case where the regenerative power voltage V2 is greater than or equal to the second threshold Th2.

[0063] Note that the first threshold Th1 is a value higher than the voltage of PbB12 and lower than the voltage of LiB21. The second threshold Th2 is a value higher than the first threshold Th1, and is a value higher than PbB12 and LiB21 by a predetermined value or more. That is, the second threshold Th2 is a value that causes an overvoltage state. For the second threshold Th2, the overvoltage threshold used in the power failure detection circuit 4 can be used. Note that since the voltages of LiB21 and PbB12 may fluctuate up and down, the magnitude relationship may differ depending on the case, but each voltage to be compared with the voltage V2 basically has the following magnitude relationship.

[0064] Th2 > LiB voltage > PbB voltage > Th1

[0065] As shown in Figures 5 to 8, the controller 3 performs different operations depending on the following cases (1) to (4) for the regenerative power voltage V2. Hereinafter, operations in each of cases (1) to (4) will be described. (1) Th1≦V2<Th2, and LiB voltage≦V2 (2) Th1≦V2<Th2, and LiB voltage>V2 (3) Th1>V2 (4) Th2≦V2

[0066] (1) Th1≦V2<Th2, and LiB voltage≦V2 First, with reference to Figure 5, the operation in case (1), that is, when the regenerative power voltage V2 is not less than the first threshold Th1, less than the second threshold Th2, and not less than the voltage of LiB21, will be described.

[0067] The controller 3 controls the charging / discharging control unit 5 such that the regenerative power is supplied to the backup power supply 20 when a voltage V2 of the regenerative power is not less than a first threshold Th1 and less than a second threshold Th2. Further, when the voltage V2 of the regenerative power is not less than the voltage of the backup power supply 20, that is, the voltage of the LiB 20 (LiB voltage), the controller 3 stops the operation of the DC / DC 23 and turns on the battery switch 43. Accordingly, the controller 3 can charge the LiB 21 with the regenerative power generated in the second load 103 via the battery switch 43.

[0068] Note that when the SOC of the LiB 21 is in a state close to full charge (the SOC is not less than a threshold value), the controller 3 may stop the operation of the DC / DC 23 (maintain the stopped state of the operation) and turn off the battery switch 43. Accordingly, the regenerative power is charged into the PbB 12 via the inter-system switch 41.

[0069] In addition, when the temperature of the LiB 21 is out of a predetermined range, there is a risk that the LiB 21 deteriorates due to charging, and therefore the controller 3 may stop the operation of the DC / DC 23 and turn off the battery switch 43. That is, when the temperature of the LiB 21 is in a low temperature state lower than a low temperature threshold or in a high temperature state not lower than a high temperature threshold, the controller 3 stops the operation of the DC / DC 23 and turns off the battery switch 43, thereby performing control such that the regenerative power is not charged into the LiB 21.

[0070] (2)Th1≦V2<Th2, and LiB voltage>V2 Next, the operation in case (2), that is, when the voltage V2 of the regenerative power is not less than the first threshold Th1, less than the second threshold Th2, and less than the voltage of the LiB 21 will be described with reference to FIG. 6.

[0071] Controller 3 controls the charge / discharge control unit 5 so that regenerative power is supplied to the backup power supply 20 when the regenerative power voltage V2 is greater than or equal to the first threshold Th1 and less than the second threshold Th2. Furthermore, if the regenerative power voltage V2 is less than the LiB voltage, Controller 3 turns off the battery switch 43 and operates the DC / DC 23 to boost the regenerative power voltage to the LiB 21 voltage or higher. As a result, Controller 3 can charge the LiB 21 via the DC / DC 23 with the regenerative power generated at the second load 103.

[0072] In addition, the controller 3 may control the charge / discharge control unit 5 in the same manner as in (1) so as not to charge the LiB21 according to the SOC and temperature of the LiB21.

[0073] (3)Th1>V2 Next, using Figure 7, we will explain the operation in case (3), that is, when the regenerative power voltage V2 is less than the first threshold Th1. Note that the state in Figure 7 includes the state in which no regenerative power is generated.

[0074] When the regenerative power voltage V2 is less than the first threshold Th1, the controller 3 turns on the inter-system switch 41 and controls the charge / discharge control unit 5 so that the regenerative power is not supplied to the backup power supply 20. Specifically, the controller 3 turns off the battery switch 43 and stops the operation of the DC / DC 23. As a result, if the regenerative power voltage V2 is higher than that of PbB12, PbB12 is charged. This allows the controller 3 to charge PbB12 with regenerative power. In other words, when the voltage V2 is less than the first threshold Th1, it is difficult to accurately determine the generation of regenerative power. In this state, either no regenerative power is generated or only a small amount is generated, so the normal switch state is maintained, and if regenerative power is generated, it is automatically charged to PbB12.

[0075] Furthermore, if, in the case of (3), the controller 3 operates the DC / DC23 to charge the LiB21 with regenerative power, the amount of power consumed to operate the DC / DC23 may exceed the amount of power charged by regenerative power. In other words, in the case of (3), operating the charge / discharge control unit 5 may result in a negative power balance, so charging of the LiB21 is not performed.

[0076] (4) Th2 ≤ V2 Next, using Figure 8, we will explain the operation in case (4), that is, when the regenerated power voltage V2 is equal to or greater than the second threshold Th2.

[0077] When the regenerative power voltage V2 is equal to or greater than the second threshold Th2, the controller 3 turns off the inter-system switch 41 and the battery switch 43, stopping the operation of the DC / DC23. The controller 3 also turns on the ground connection switch 61. Since a number of diodes 62 capable of dropping the voltage by the amount of the second threshold Th2 is connected between the ground connection switch 61 and ground, the regenerative power flows to ground through the diodes 62. In other words, the diodes 62 only allow regenerative power with a voltage V2 equal to or greater than the second threshold Th2 to pass to the ground. Note that the power supplied from LiB21 to the second load 103 has a voltage less than the second threshold Th2, so it does not flow to ground and is supplied to the second load 103. In short, the controller 3 directs the generated regenerative power to ground via the ground connection switch 61. This allows the controller 3 to prevent damage to PbB12 and LiB21 from being caused by overvoltage regenerative power being supplied to them. Furthermore, the diode 62 allows only regenerative power, where the voltage V2 is equal to or greater than the second threshold Th2, to pass to the ground, thus preventing power supplied from the backup power supply 20 to the second load 103 from flowing to ground. In other words, the power control device 1 can stably supply power from the backup power supply 20 to the second load 103.

[0078] Furthermore, the diode 62 may be configured to drop the voltage of LiB21 rather than being configured to drop the voltage of the second threshold Th2.

[0079] In Figure 8, an example is shown where the battery switch 43 is in the OFF state, but it may also be kept in the ON state. In this case, the regenerative power, whose voltage has dropped due to discharge to ground via the diode 62, may be used to charge the backup power supply 20 via the ON battery switch 43 or DC / DC 23.

[0080] Furthermore, the second threshold Th2 may be a voltage lower than the voltage used to detect overvoltage in power failure, as described in Figures 2-4. In this case, if the voltage V2 is higher than the second threshold Th2 and equal to the threshold for detecting power failure, as described in Figures 2-4, the processing for power failure, as described in Figures 2-4, may be performed.

[0081] Next, the processing procedure for the regenerative power operation of the power control device 1 according to the embodiment will be described using Figure 9. Figure 9 is a flowchart showing the processing procedure for the regenerative power operation of the power control device 1 according to the embodiment. The flowchart shown in Figure 9 is repeated from when the vehicle's IG is turned on until it is turned off.

[0082] As shown in Figure 9, the controller 3 first determines whether or not regenerative power has been detected based on the value detected by the second voltage sensor 52 (step S101). If the controller 3 has detected regenerative power (step S101: Yes), it determines whether or not the regenerative power voltage V2 is greater than or equal to the first threshold Th1 (step S102).

[0083] If the regenerative power voltage V2 is greater than or equal to the first threshold Th1 (step S102: Yes), the controller 3 determines whether the voltage V2 is greater than or equal to the second threshold Th2 (step S103).

[0084] If the regenerative power voltage V2 is greater than or equal to the second threshold Th2 (step S103: Yes), the controller 3 performs the process in step S104 and terminates the process. That is, in step S104, the controller 3 turns off the inter-system switch 41, turns off the battery switch 43, stops the operation of DC / DC23, and turns on the ground connection switch 61, thereby sending the regenerative power to the ground.

[0085] On the other hand, in step S103, if the regenerative power voltage V2 is less than the second threshold Th2 (step S103: No), the controller 3 determines whether the voltage V2 is equal to or greater than the LiB voltage (step S105). If the regenerative power voltage V2 is equal to or greater than the LiB voltage (step S105: Yes), the controller 3 performs the process in step S106 and terminates the process. That is, in step S106, the controller 3 charges the LiB21 with regenerative power via the battery switch 43 by turning on the inter-system switch 41, turning on the battery switch 43, stopping the operation of the DC / DC23, and turning off the ground connection switch 61.

[0086] On the other hand, in step S105, if the regenerative power voltage V2 is less than the LiB voltage (step S105: No), the controller 3 performs the process in step S107 and terminates the process. That is, in step S107, the controller 3 turns on the inter-system switch 41, turns off the battery switch 43, operates the DC / DC 23, and turns off the ground connection switch 61, thereby boosting the regenerative power using the DC / DC 23 to charge the LiB 21.

[0087] Furthermore, in step S102, if the regenerative power voltage V2 is less than the first threshold Th1 (step S102: No), the controller 3 performs the process in step S108 and terminates the process. That is, in step S108, the controller 3 turns on the inter-system switch 41, turns off the battery switch 43, stops the operation of DC / DC23, and turns off the ground connection switch 61. As a result, if the regenerative power voltage V2 is higher than PbB12, PbB12 is charged.

[0088] Furthermore, if the controller 3 does not detect regenerative power in step S101 (step S101: No), it performs the process in step S108 and terminates the process. That is, in step S108, the controller 3 turns on the inter-system switch 41, turns off the battery switch 43, stops the operation of DC / DC23, and turns off the ground connection switch 61. As a result, the controller 3 supplies power from PbB12 to each load, including the second load 103. Note that if the generation of regenerative power is detected based on the voltage V2, step S101 may be omitted. In this case, the determination in step S102 effectively becomes the process of detecting the generation of regenerative power.

[0089] As described above, the power control device 1 according to this embodiment comprises a first system 110, a second system 120, an inter-system switch 41, and a controller 3. The first system 110 has a main power supply 10 connected to a first load 101. The second system 120 has a backup power supply 20 connected to a second load 103 via a charge / discharge control unit 5. The inter-system switch 41 connects the first system 110 and the second system 120. The controller 3 normally turns on the inter-system switch 41 and controls the charge / discharge control unit 5 so that it does not perform charging or discharging. When the controller 3 detects the generation of regenerative power from the second load 103, it controls the charge / discharge control unit 5 so that the regenerative power is supplied to the backup power supply 20.

[0090] According to this disclosure, the power control device 1 controls the charge / discharge control unit 5 so that when regenerative power is generated in the first load 101 or the second load 103, the regenerative power is supplied to the backup power supply 20. As a result, the power control device 1 can charge the backup power supply 20 with the regenerative power generated in the first load 101 or the second load 103.

[0091] In the embodiment described above, the case where the power system consists of two systems, the first system 110 and the second system 120, was given as an example. However, the method is also applicable when the number of power systems is three or more. The case where the number of power systems is three or more will be explained below with reference to Figures 10 and 11.

[0092] Figures 10 and 11 illustrate the configuration and operation of a modified power control device 1. Figures 10 and 11 are explanatory diagrams of the configuration and operation of a modified power control device 1. Note that while Figures 10 and 11 show an example where there are three power systems, there may be four or more systems.

[0093] As shown in Figure 10, the modified power control device 1 comprises a first system 110, a second system 120, and a third system 140. Note that the controller 3 and the power failure detection circuit 4 are not shown in Figures 10 and 11. In the modified example, the controller 3 and the power failure detection circuit 4 may be provided for the second system 120 and the third system 140 respectively, and the second system 120 and the third system 140 may be controlled by one controller 3 and one power failure detection circuit 4.

[0094] The first system 110 is a power system in which the main power supply 10 is connected to the first load 101 and the general load 102. The second system 120 is a power system in which the backup power supply 20-1 is connected to the second load 103. The third system 140 is a power system in which the backup power supply 20-2 is connected to the third load 104. In other words, in this modified example, unlike the embodiment described above, the power control device 1 has multiple backup power supplies 20-1 and 20-2 connected to different power systems to supply power to each load.

[0095] Furthermore, the first system 110 and the second system 120 are connected by an inter-system line 130-1 equipped with an inter-system switch 41-1. The first system 110 and the third system 140 are connected by an inter-system line 130-2 equipped with an inter-system switch 41-2. Inter-system switch 41-1 is a switch capable of connecting and disconnecting the first system 110 and the second system 120. Inter-system switch 41-2 is a switch capable of connecting and disconnecting the first system 110 and the third system 140. Note that inter-system switch 41-1 is the first inter-system switch, and inter-system switch 41-2 is the second inter-system switch.

[0096] Furthermore, the second system 120 includes a system relay 42-1, a charge / discharge control unit 5-1, a second voltage sensor 52, a ground connection switch 61-1, and a diode 62-1. Furthermore, the third system 140 includes a system relay 42-2, a charge / discharge control unit 5-2, a third voltage sensor 53, a ground connection switch 61-2, and a diode 62-2. As in the embodiment described above, the value detected by the third voltage sensor 53 is referred to as the third system voltage V3.

[0097] The second load 103, like the implementation system described above, includes some of the functions for autonomous driving provided by the first load 101. The second load 103 includes, for example, the minimum necessary equipment for FOP, such as a steering motor, an electric brake system, and radar.

[0098] The third load 104, like the second load 103, includes some of the functions for autonomous driving provided by the first load 101. The second load 103 includes, for example, the minimum necessary equipment for FOP, such as a steering motor, electric brakes, and radar.

[0099] The following describes the normal operation of the modified power control device 1.

[0100] In the modified power control device 1 (controller 3, not shown), under normal conditions, the inter-system switches 41-1 and 41-2 are turned on, and the system relays 42-1 and 42-2 are also turned on. Furthermore, under normal conditions, the power control device 1 controls the charge / discharge control unit 5 so that it does not perform charging or discharging. As a result, the power control device 1 supplies power from the main power supply 10 to the first load 101, general load 102, second load 103, and third load 104. Specifically, the power control device 1 supplies power from the main power supply 10 to the first load 101 and general load 102 via the first system 110. The power control device 1 also supplies power from the main power supply 10 to the second load 103 via the inter-system switch 41-1. The power control device 1 also supplies power from the main power supply 10 to the third load 104 via the inter-system switch 41-2.

[0101] In the modified version, a fault is determined for each power system. Specifically, first, the power control device 1 provisionally determines that a ground fault has occurred in at least one of the first system 110, second system 120, and third system 140 when the voltages of the first system V1, second system V2, and third system V3 fall below the ground fault threshold. Subsequently, the power control device 1 outputs an automatic operation prohibition signal to the automatic operation control device 100.

[0102] Then, when the power control device 1 provisionally determines that a ground fault has occurred, it turns off the inter-system switches 41-1 and 41-2 and turns on the battery switches 43-1 and 43-2. ​​This disconnects the connection between the first system 110 and the second system 120, and the connection between the first system 110 and the third system 140. As a result, power is supplied from the main power supply 10 to the first system 110, from the backup power supply 20-1 to the second system 120, and from the backup power supply 20-2 to the third system 140.

[0103] Furthermore, the power control device 1 can also provisionally determine that a ground fault has occurred in at least one of the first system 110, second system 120, and third system 140 when at least one of the first system voltage V1, second system voltage V2, and third system voltage V3 falls below the ground fault threshold.

[0104] Next, the power control device 1 makes a preliminary determination that a ground fault has occurred, and then performs a final determination to determine which system has the ground fault. By turning off the inter-system switches 41-1 and 41-2 and turning on the battery switches 43-1 and 43-2, the system voltage of the system without a ground fault returns to a normal state, while the system voltage of the system with a ground fault continues to decrease. This final determination is performed for each system, but the details of the determination method are the same as in the embodiment described above, so the explanation is omitted.

[0105] If the power control device 1 determines, for example, that a ground fault has occurred only in the second system 120, it will keep the inter-system switch 41-1 in the off state and turn on the inter-system switch 41-2. This will disconnect the abnormal second system 120, connect the normal third system 140 to the first system 110, and supply power from the main power supply 10 to the third load 104.

[0106] Furthermore, if the power control device 1 determines, for example, that a ground fault has occurred only in the third system 140, it will keep the inter-system switch 41-2 in the off state and turn on the inter-system switch 41-1. This will disconnect the abnormal third system 140, connect the normal second system 120 to the first system 110, and supply power from the main power supply 10 to the second load 103.

[0107] Next, using Figure 11, the operation of the modified power control device 1 during regenerative power generation will be explained. In Figure 11, the explanation will be given using the example of regenerative power generation at the third load 104.

[0108] When the power control device 1 detects the generation of regenerative power at the third load 104 based on the value detected by the third voltage sensor 53 (referred to as voltage V3), it controls the device to charge the regenerative power if the voltage V3 is greater than or equal to the first threshold Th1 and less than the second threshold Th2. In Figure 11, it is assumed that the regenerative power voltage V3 is higher than the voltage of LiB21-1 and 21-2.

[0109] In this case, the power control device 1 decides which of the LiB21-1 and 21-2 to charge with regenerative power based on their State of Charge (SOC). Specifically, the power control device 1 charges the LiB21-1 with regenerative power to the one with the lower SOC. In Figure 11, it is assumed that the SOC of LiB21-1 is 60% and the SOC of LiB21-2 is 80%.

[0110] In the example shown in Figure 11, the power control device 1 controls the regenerative power generated at the third load 104 to charge LiB21-1 because LiB21-1 has a lower State of Charge (SOC) than LiB21-2. Specifically, the power control device 1 turns on battery switch 43-1 and off battery switch 43-2. ​​As a result, the regenerative power is charged to LiB21-1 via the inter-system switch 41-2, the first system 110, and the inter-system switch 41-1. In other words, when there are multiple backup power supplies 20-1 and 20-2, the power control device 1 prioritizes charging the one with the lower SOC using regenerative power.

[0111] Furthermore, if the voltage V3 of the regenerative power generated at the third load 104 is equal to or greater than the second threshold Th2, the power control device 1 turns off the inter-system switch 41-2, turns on the battery switch 43-2, and turns on the ground connection switch 61-2. This allows the overvoltage regenerative power to flow to the ground via the ground connection switch 61-2, and also allows power to be supplied from the backup power supply 20-2 to the third load 104, which has been disconnected from the first system 110.

[0112] Note that the first load 101 and the second load 103 in Figures 1 to 8, the first load 101 and the second load 103 in Figures 10 and 11, and the first load 101 and the third load 104 may all be the same load. In that case, although each load is connected to only one system in each figure, a configuration in which one load is connected to multiple systems is also possible.

[0113] Figure 11 shows the case where regenerative power is generated at the third load 104, but the same approach to charging regenerative power as described above can also be used when regenerative power is generated at the second load 103.

[0114] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0115] 1 Power supply control device 3 Controllers 4. Power failure detection circuit 5. Charge / Discharge Control Unit 10 Main power 11 DC / DC 20 Backup power supply 22 Status monitoring lines 23 DC / DC 41 Inter-system switches 42 System Relays 43 Battery Switch 51. First voltage sensor 52 Second Voltage Sensor 53 Third Voltage Sensor 61 Ground connection switch 62 diodes 100 Automatic Driving Control System 101 1st load 102 General load 103 2nd load 104 Third load 110 1st system 120 2nd system 130 Inter-system lines 140 3rd system 210 High-voltage battery 300 Motor for driving

Claims

1. The first system is connected to the first load, A second system in which the backup power supply is connected to the second load via the charge / discharge control unit, A system-to-system switch connecting the first system and the second system, A controller that normally turns on the inter-system switch and controls the charge / discharge control unit so that it does not perform charging or discharging, Equipped with, The aforementioned controller, When the generation of regenerative power from the second load is detected, the charge / discharge control unit is controlled so that the regenerative power is supplied to the backup power supply. Power supply control device.

2. The charge / discharge control unit, The system includes a battery switch that connects the charging and discharging path between the backup power supply and the second system, and a DC-DC converter provided in parallel with the battery switch. The aforementioned controller, If the regenerative power voltage is equal to or greater than the backup power supply voltage, the operation of the DCDC converter is stopped and the battery switch is turned on. If the regenerative power voltage is less than the backup power supply voltage, the battery switch is turned off and the DCDC converter is operated to boost the regenerative power voltage to equal to or greater than the backup power supply voltage. The power control device according to claim 1.

3. The aforementioned controller, If the voltage of the regenerated power is equal to or greater than a first threshold and less than a second threshold that is higher than the first threshold, the charge / discharge control unit is controlled so that the regenerated power is supplied to the backup power supply. If the voltage of the regenerated power is equal to or greater than the second threshold, the inter-system switch is turned off. The power control device according to claim 1.

4. The system further includes a ground connection switch connected to the path between the charge / discharge control unit and the second load, and connecting the path to ground. The aforementioned controller, If the regenerative power voltage is equal to or greater than the second threshold, the inter-system switch is turned off and the ground connection switch is turned on. The power control device according to claim 3.

5. The system further comprises a diode provided between the ground connection switch and the ground, which allows the regenerative power, whose voltage is equal to or greater than the second threshold, to pass to the ground side. The power control device according to claim 4.

6. The aforementioned controller, If the voltage of the regenerated power is less than the first threshold, the inter-system switch is turned on, and the charge / discharge control unit is controlled so that the regenerated power is not supplied to the backup power supply. The power control device according to claim 3.

7. The aforementioned main power supply is It is connected to the high-voltage battery to which the drive motor is connected. The regenerative power generated by the aforementioned drive motor is supplied to the aforementioned high-voltage battery. The second load is, This is a load other than the aforementioned drive motor. The power control device according to claim 1.

8. A third system different from the second system, wherein the backup power supply is connected to the third load via a charge / discharge control unit, A second inter-system switch, which is different from the first inter-system switch that connects the first system and the second system, and which connects the first system and the third system, Furthermore, The aforementioned controller, When regenerative power is detected in either the second load or the third load, the regenerative power is used to charge the backup power supply connected to the second system and the backup power supply connected to the third system that has the lower remaining charge. The power control device according to claim 1.

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