Power supply controller

Abstract

To provide a power supply controller that suppresses unnecessary supply of power of a second power supply to a steering system.SOLUTION: A PU determines that a control of a steering system is requested, when a logical OR between a condition of the fact that a start switch is on, and another condition of the fact that an absolute value of a vehicle speed V is a threshold value Vth or more is determined to be true (S16). Then, the PU sets a control mode to a backup standby mode (S18). The backup standby mode is a mode of executing backup, when it is detected that it is abnormal to feed power from a low voltage battery.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Patent Document 1 below describes a power supply device that supplies power to an actuator of a vehicle steering system. This power supply device includes an auxiliary power supply that supplies power to the actuator of the steering system when the power supply from the main power supply is abnormal.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the case of the above device, for example, when the main power supply is removed during vehicle maintenance, the auxiliary power supply may be used unnecessarily, such as the power of the auxiliary power supply being supplied to the steering system.

Means for Solving the Problems

[0005] Hereinafter, means for solving the above problems and their effects will be described. 1. A power control device applied to a vehicle having a first power source and a second power source that supply power to a steering system, wherein the second power source is a backup power source that supplies power to the steering system when there is an abnormality in the power supply to the steering system by the first power source, and is configured to execute a backup process, a determination process, and a permission process. The backup process is a process of supplying power of the second power source to the steering system when an abnormality in the power supply to the steering system by the first power source is detected. The determination process is a process of determining whether control of the steering system is required. The permission process is a process of permitting the backup process when it is determined that control of the steering system is required.

[0006] In the above configuration, since the backup process is permitted when it is determined that control of the steering system is required, it is possible to suppress the unnecessary supply of power of the second power source to the steering system. 2. The power control device according to item 1 above, wherein the permission process is a process of setting the control mode to a backup standby mode when it is determined that control of the steering system is required, and the backup process is a process of supplying power of the second power source to the steering system when an abnormality in the power supply is detected in the backup standby mode.

[0007] In the above configuration, in addition to the condition that there is an abnormality in the power supply, the condition that it is determined that control of the steering system is required can be easily included in the execution condition of the process of supplying power of the second power source to the steering system.

[0008] 3. The power control device according to item 1 or 2 above, wherein the vehicle includes a rotating electric machine as a thrust generating device, and the determination process includes a process of determining that control of the steering system is required when it indicates that the rotating electric machine is in a drivable state.

[0009] When the rotating electric machine is in a drivable state, since the vehicle can travel, it is a state where control of the steering system is required. Therefore, in the above configuration, it is possible to accurately determine whether control of the steering system is required.

[0010] 4. The power supply control device according to any one of 1 to 3 above, wherein the determination process includes a process of determining that control of the steering system is required when the vehicle speed is equal to or higher than a predetermined value. When the vehicle speed is equal to or higher than a predetermined value, it is necessary to control the displacement direction of the vehicle, and thus the state in which control of the steering system is required. Therefore, with the above configuration, it is possible to accurately determine whether control of the steering system is required.

[0011] 5. The vehicle includes a rotating electric machine as a thrust generating device, and the determination process includes a process of determining that control of the steering system is required when the vehicle speed is equal to or higher than a predetermined value regardless of whether the rotating electric machine is in a drivable state. The power supply control device according to any one of 1 to 4 above.

[0012] When the rotating electric machine is not in a drivable state, the vehicle cannot be driven by the thrust of the rotating electric machine. However, even in that case, for example, when the vehicle stops on a slope, the vehicle may be displaced due to the influence of gravity. And in that case, since it is necessary to control the displacement direction of the vehicle, the state in which control of the steering system is required. Therefore, with the above configuration, it is possible to accurately determine whether control of the steering system is required.

[0013] 6. The steering system includes a steering actuator that cuts off the power transmission between the steering shaft and the steered wheels and steers the steered wheels, and the first power supply and the second power supply are configured to supply power to the steering actuator. The power supply control device according to any one of 1 to 5 above.

[0014] In the case of the above configuration, the steering angle of the steered wheels cannot be changed by operating the steering shaft. Therefore, the utility value of making it possible to supply the power of both the first power supply and the second power supply to the steering actuator is particularly large.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment will be described with reference to the drawings. 「Configuration of Vehicle」 FIG. 1 shows the power transmission system of the vehicle according to this embodiment.

[0017] To the wheels 12 of the vehicle 10 shown in FIG. 1, the power of the motor generator 14 as an in-vehicle thrust generating device is applied. The output voltage of the inverter 16 is applied to each terminal of the motor generator 14. To the input terminals of the inverter 16, a high-voltage battery 20 as a DC voltage source is connected via the system main relay 18. The terminal voltage of the high-voltage battery 20 may be, for example, several tens to several hundreds of V.

[0018] The voltage of the high-voltage battery 20 is stepped down by the DCDC converter 22 and applied to the low-voltage battery 24. The terminal voltage of the low-voltage battery 24 is smaller than the terminal voltage of the high-voltage battery 20. The low-voltage battery 24 is a lead-acid battery.

[0019] The steering device 30 includes a steering wheel 32, a steering shaft 33, and a reaction force motor 34. The reaction force motor 34 is configured to apply a reaction force against the operation of the steering wheel 32 to the steering wheel 32.

[0020] The steering device 30 includes a steering motor 40. The steering motor 40 is configured to steer the wheels 12 as steering wheels. The reaction force ECU 50 and the steering ECU 60 are control devices that control the steering wheel 32 and the wheels 12, respectively. The reaction force ECU 50 and the steering ECU 60 are configured to be supplied with power from the power supply circuit 70.

[0021] "Details of the power supply system" Fig. 2 shows the configurations of the reaction force ECU 50, the steering ECU 60, and the power supply circuit 70. The low-voltage battery 24 is capable of supplying power via the main power line Lb and is also capable of supplying power via the start switch 26 and the start-up line Lig. The start switch 26 is a switch that enables the vehicle to run. The start switch 26 can be switched from either the on state or the off state to the other by the operation of the vehicle user. As an example, the start switch 26 may be a switch that is interlocked with the on / off of the system main relay 18.

[0022] The reaction force ECU 50 includes a reaction force main control device 50a and a reaction force sub-control device 50b. The reaction force main control device 50a and the reaction force sub-control device 50b each include an inverter 52 and a microcomputer 54. The inverter 52 applies an AC voltage to the terminals of the reaction force motor 34 provided in the reaction force actuator. The microcomputer 54 operates the inverter 52 to control the steering wheel 32 as the control target. Note that the inverter 52 provided in the reaction force main control device 50a and the inverter 52 provided in the reaction force sub-control device 50b may be configured to apply AC voltages to different stator coils of the reaction force motor that share the rotor.

[0023] The steering ECU 60 includes a main steering control device 60a and a sub-steering control device 60b. The main steering control device 60a and the sub-steering control device 60b each include an inverter 62 and a microcomputer 64. The inverter 62 applies an alternating voltage to the terminals of the steering motor 40 provided in the steering actuator. Note that the inverter 62 included in the main steering control device 60a and the inverter 62 included in the sub-steering control device 60b may be configured to apply alternating voltages to different stator coils of the steering motor that share a rotor.

[0024] The power supply circuit 70 includes a device that controls the state of the auxiliary power supply 100 as a control target. The auxiliary power supply 100 is a power storage device that stores the charge from the low-voltage battery 24. The auxiliary power supply 100 is, for example, a capacitor.

[0025] The power supply circuit 70 includes a switching element 72 that opens and closes between the inverters 52 of the reaction force main control device 50a and 62 of the steering main control device 60a and the main power line Lb. The power supply circuit 70 includes a switching element 74 that opens and closes between the main power line Lb and the auxiliary power supply 100 via the switching element 72. The power supply circuit 70 includes a diode 78 that connects the auxiliary power supply 100 to the microcomputer 54 of the reaction force main control device 50a and the microcomputer 64 of the steering main control device 60a. The diode 78 is a rectifying element with the positive terminal side of the auxiliary power supply 100 as the anode and the sides of the microcomputer 54 of the reaction force main control device 50a and the microcomputer 64 of the steering main control device 60a as the cathode. The power supply circuit 70 includes a diode 80 that connects the startup line Lig to the microcomputer 54 of the reaction force main control device 50a and the microcomputer 64 of the steering main control device 60a. The diode 80 is a rectifying element with the low-voltage battery 24 side as the anode and the diode 80 side as the cathode. The power supply circuit 70 includes a switching element 76 that opens and closes between the inverters 52 of the reaction force main control device 50a and 62 of the steering main control device 60a and the auxiliary power supply 100. Specifically, the switching element 76 is configured to open and close between the anode side of the diode 78 and the auxiliary power supply 100.

[0026] The power supply circuit 70 includes an auxiliary microcomputer 90. The auxiliary microcomputer 90 includes a PU 92 and a storage device 94. The PU 92 is a software processing device such as a CPU and a GPU. The storage device 94 may be an electrically rewritable non-volatile memory and a storage medium such as a disk medium. The PU 92 executes various processes by executing the programs stored in the storage device 94.

[0027] That is, PU92 detects the voltage and current of the auxiliary power supply 100 to monitor the state of the auxiliary power supply 100. By opening and closing the switching element 72, PU92 controls the power supply from the low-voltage battery 24 to the inverters 52 and 62. Also, by opening and closing the switching element 74, PU92 controls the power transfer between the auxiliary power supply 100 and the low-voltage battery 24, and the power transfer between the inverters 52 and 62 and the auxiliary power supply 100. Further, by opening and closing the switching element 76, PU92 controls the power supply from the auxiliary power supply 100 to the microcomputer 54 of the reaction force main control device 50a and the microcomputer 64 of the steering main control device 60a. Additionally, by opening and closing the switching element 82, PU92 controls the power supply from the auxiliary power supply 100 to the inverter 52 of the reaction force main control device 50a and the inverter 62 of the steering main control device 60a.

[0028] "Backup Control" The auxiliary power supply 100 is a backup power supply used when the low-voltage battery 24 cannot perform sufficient functions to follow the control of the steering system. PU92 executes a process of switching the control mode according to the state of the low-voltage battery 24.

[0029] FIG. 3 shows the procedure of the above switching process. The series of processes shown in FIG. 3 is realized by PU92 repeatedly executing a program stored in the storage device 94, for example, at a predetermined cycle. Hereinafter, the step numbers of each process are represented by numbers preceded by "S".

[0030] In the series of processes shown in FIG. 3, PU92 first acquires the vehicle speed V detected by the vehicle speed sensor 110 shown in FIG. 1 (S10). Also, PU90 acquires the state of the start switch (S12). Then, PU92 determines whether the logical sum of the following conditions (A) and (B) is true (S14).

[0031] Condition (A): A condition indicating that the start switch is in the on state. Condition (B): A condition that the absolute value of the vehicle speed V is greater than or equal to the threshold value Vth. The threshold value Vth is set to a value greater than zero.

[0032] When PU92 determines that the logical sum of the above conditions (A) and (B) is true (S14: YES), it determines that there is a control request for the steering system (S16). That is, when the start switch is in the ON state, since the vehicle can run, PU92 determines that there is a request for steering control. Also, regardless of the state of the start switch, when the absolute value of the vehicle speed V is greater than or equal to the threshold value Vth, PU92 determines that there is a request for steering control. That is, even if the start switch is not in the ON state, for example, when the vehicle is displaced due to a slope, PU92 determines that there is a request for steering control. Then, PU92 sets the control mode to the backup standby mode (S18). The backup standby mode is a mode that executes backup when an abnormality is detected in the power supply from the low-voltage battery 24.

[0033] On the other hand, when PU92 determines that the logical sum is false (S14: NO), it sets the control mode to the non-backup mode (S20). In other words, PU92 sets the control mode to a mode in which the process of switching the switching elements 76, 82 to the ON state is not executed regardless of whether there is an abnormality in the power supply from the low-voltage battery 24.

[0034] Note that when PU92 completes the processes of S18 and S20, it temporarily ends the series of processes shown in FIG. 3. FIG. 4 shows the procedure of the process regarding the use of the auxiliary power supply 100. The process shown in FIG. 4 is realized by PU92 repeatedly executing the program stored in the storage device 94, for example, at a predetermined cycle.

[0035] In the series of processes shown in FIG. 4, PU92 first determines whether the control mode is the backup mode (S30). If PU92 determines that the control mode is not the backup mode (S30: NO), it determines whether the control mode is the backup standby mode (S32). If PU92 determines that the control mode is the backup standby mode (S32: YES), it acquires the terminal voltage Vb of the low-voltage battery 24 (S34). Then PU92 determines whether the terminal voltage Vb is less than or equal to the threshold value Vth (S36). This process is a process for determining whether power supply from the low-voltage battery 24 to the steering system can be performed normally. If PU36 determines that it is less than or equal to the threshold value Vth (S36: YES), it determines that there is an abnormality that power supply from the low-voltage battery 24 to the steering system cannot be performed normally (S38). In other words, PU92 determines that there is an abnormality in the low-voltage battery 24.

[0036] Then PU92 sets the control mode to the backup mode (S40). Then, PU92 controls the power of the auxiliary power supply 100 to a state where it can be supplied to the reaction force main control device 50a and the steering main control device 60a (S42). That is, PU92 controls the switching elements 72, 76, 82 to the on state.

[0037] On the other hand, if PU92 determines that the control mode is the backup mode (S30: YES), it determines whether the state of the low-voltage battery 24 has returned to a state where power supply to the steering system can be performed normally (S44). PU92 may determine that the state of the low-voltage battery 24 has returned when, for example, the terminal voltage Vb becomes equal to or greater than a predetermined value greater than the threshold value Vth.

[0038] If PU92 determines that the state of the low-voltage battery 24 has returned (S44: YES), it releases the backup mode (S46). In other words, PU92 switches the control mode to the backup standby mode. On the other hand, if PU92 determines that the state of the low-voltage battery 24 has not returned (S44: NO), it proceeds to the process of S42.

[0039] When PU92 completes the processing of S42 and S46, or when a negative determination is made in the processing of S32 and S36, it temporarily ends the series of processing shown in FIG. 4. "Operations and Effects of the Present Embodiment" When the logical sum of the activation switch being in the ON state and the absolute value of the vehicle speed V being equal to or greater than the threshold value Vth is true, PU92 determines that control of the steering system is required. And in that case, PU92 sets the control mode to the backup standby mode. Thereby, when an abnormality occurs in the power supply from the low-voltage battery 24 to the steering system, PU92 can supply the power of the auxiliary power supply 100 to the steering system.

[0040] On the other hand, when the above logical sum is false, PU92 sets the control mode to the non-backup mode. Thereby, for example, during maintenance, PU92 sets the control mode to the non-backup mode. Therefore, even if the terminal voltage Vb detected by PU92 is equal to or lower than the threshold value Vth due to the removal of the low-voltage battery 24 during maintenance, PU92 does not set the control mode to the backup mode. Therefore, it is possible to suppress the control mode from being unnecessarily set to the backup mode. Therefore, since wasteful energy consumption can be reduced, it is possible to suppress the shortening of the product life.

[0041] According to the present embodiment described above, the following operations and effects can be obtained. (1) Even when the activation switch is in the OFF state, PU92 determines that control of the steering system is required when the absolute value of the vehicle speed V is equal to or greater than the threshold value Vth. Therefore, for example, after the vehicle stops on a slope and the activation switch is in the OFF state, even if the vehicle is displaced due to the influence of gravity, it can be determined that the control of the steering system is required. Therefore, in such a situation, when an abnormality occurs in the power supply from the low-voltage battery 24 to the steering system, the control of the steering system can be realized using the power of the auxiliary power supply 100.

[0042] (2) In the steering system, the power transmission between the steering shaft 33 and the wheel 12 is interrupted. Therefore, the wheel 12 cannot be steered depending on the operation of the steering wheel 32. Therefore, the utility value of using both the low-voltage battery 24 and the auxiliary power supply 100 as the power supply for the actuator for steering the wheel 12 as the steered wheel is particularly high.

[0043] <Corresponding relationship> The corresponding relationship between the matters in the above embodiment and the matters described in the column of "Means for Solving the Problems" is as follows. Below, the corresponding relationship is shown for each number of the solution means described in the column of "Means for Solving the Problems". [1] The first power supply corresponds to the low-voltage battery 24. The second power supply corresponds to the auxiliary power supply 100. The backup process corresponds to the processes of S34 to S42. The determination process corresponds to the processes of S14 and S16. The permission process corresponds to the process of S18. [2] "When an abnormality in the power supply is detected in the backup standby mode" corresponds to the case where an affirmative determination is made in the process of S32 and the case where an affirmative determination is made in the process of S36. [3] Corresponds to the above condition (A). [4, 5] Corresponds to the above condition (B). [6] The steering actuator corresponds to the actuator including the steering motor 40.

[0044] <Other embodiments> Note that this embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non-conflicting range.

[0045] "Regarding the determination process" · It is not essential that the determination process is a process for determining whether the logical sum of the above conditions (A) and (B) is true. For example, the determination process may be a process for determining whether the above condition (A) is satisfied. Also, for example, the determination process may be a process for determining whether the above condition (B) is satisfied.

[0046] "Regarding the backup process" The process for determining whether there is an abnormality in the power supply from the low-voltage battery 24 to the steering system is not limited to the process of determining whether the terminal voltage Vb is equal to or lower than the threshold value Vth. For example, it may be the process of determining whether the charging rate of the low-voltage battery 24 is equal to or lower than a threshold value. Also, for example, it may be the process of determining whether the internal resistance value of the low-voltage battery 24 is equal to or higher than a predetermined value.

[0047] "About the first power source" The low-voltage battery 24 as the first power supply does not necessarily have to be a lead-acid battery. The first power supply may be, for example, a secondary battery such as a nickel-metal hydride secondary battery.

[0048] "About the second power source" The destinations to which the power of the auxiliary power supply 100 serving as the second power supply is supplied do not necessarily have to be limited to the reaction force main control device 50a and the steering main control device 60a. For example, the destinations to which the power of the auxiliary power supply 100 is supplied may also include the reaction force sub-control device 50b and the steering sub-control device 60b. Also, for example, the destinations to which the power of the auxiliary power supply 100 is supplied may be limited to the reaction force sub-control device 50b and the steering sub-control device 60b.

[0049] It is not essential that the destinations of the power supply from auxiliary power supply 100 as the second power supply include both the reaction motor 34 that constitutes the reaction actuator and the microcomputer 54. For example, of the two that constitute the reaction actuator, the reaction motor 34 and the microcomputer 54, the power may be supplied to only one of them, such as only the reaction motor 34.

[0050] It is not essential that the destinations of the power supply from auxiliary power supply 100 as the second power supply include both steering motor 40 constituting the steering actuator and microcomputer 64. For example, of the two components constituting the steering actuator, steering motor 40 and microcomputer 64, the power may be supplied to only one of them, such as steering motor 40 only.

[0051] ·It is not essential that the auxiliary power source 100 as the second power source is a capacitor. The second power source may be, for example, a secondary battery such as a lithium-ion secondary battery. "Others" ·It is not essential that the reaction force ECU 50 includes the reaction force main control device 50a and the reaction force sub-control device 50b. For example, the reaction force ECU 50 may include only the reaction force main control device 50a. Also, for example, the reaction force ECU 50 may include three or more control devices.

[0052] ·It is not essential that the steering ECU 60 includes the steering main control device 60a and the steering sub-control device 60b. For example, the steering ECU 60 may include only the steering main control device 60a. Also, for example, the steering ECU 60 may include three or more control devices.

[0053] ·The DC voltage source that supplies power to the motor generator 14 as the rotating electrical machine is not limited to the high-voltage battery 20. For example, it may be a fuel cell. ·It is not essential that the thrust generation device of the vehicle is a rotating electrical machine. For example, it may be an internal combustion engine. In that case, the start switch in the above condition (A) may be an ignition switch.

[0054] ·Power transmission between the steering shaft 33 and the wheel 12 as the steered wheel may be possible.

Explanation of Reference Numerals

[0055] 10…Vehicle 12…Wheel 14…Motor Generator 16…Inverter 18…System Main Relay 20…High-Voltage Battery 24…Low-Voltage Battery 26…Start Switch 70…Power Supply Circuit 100…Auxiliary Power Source

Claims

1. Applied to a vehicle equipped with a first power source and a second power source that supply power to a steering system, wherein the second power source is a backup power source that supplies power to the steering system when there is an abnormality in the power supply to the steering system by the first power source, configured to execute a backup process, a determination process, and a permission process, wherein the backup process is a process of supplying power of the second power source to the steering system when an abnormality in the power supply to the steering system by the first power source is detected, wherein the determination process is a process of determining whether control of the steering system is requested, and wherein the permission process is a process of permitting the backup process when it is determined that control of the steering system is requested. A power control device.

2. The permission process is a process of setting a control mode to a backup standby mode when it is determined that control of the steering system is requested, and the backup process is a process of supplying power of the second power source to the steering system when an abnormality in the power supply is detected in the backup standby mode. The power control device according to claim 1.

3. The vehicle includes a rotating electric machine as a thrust generating device, and the determination process includes a process of determining that control of the steering system is requested when it indicates that the rotating electric machine is in a drivable state. The power control device according to claim 1.

4. The determination process includes a process of determining that control of the steering system is requested when the vehicle speed is equal to or higher than a predetermined value. The power control device according to claim 1.

5. The vehicle includes a rotating electric machine as a thrust generating device, and the determination process includes a process of determining that control of the steering system is requested when the vehicle speed is equal to or higher than a predetermined value regardless of whether the rotating electric machine is in a drivable state. The power control device according to claim 1.

6. The steering system includes a steering actuator that steers the steered wheels while interrupting the power transmission between the steering shaft and the steered wheels, and the first power source and the second power source are configured to supply power to the steering actuator. The power control device according to claim 1.

Images