On-vehicle power distribution system

Abstract

Provided is an on-vehicle power distribution system in which a plurality of electronic control units are hierarchically connected to each other with a plurality of loads connected thereto at the lowest level, wherein: an upper-level controller provides, to a lower-level controller, information for setting a first threshold value and a second threshold value in accordance with a power distribution state of a load in a vehicle; and the lower-level controller compares a current consumption value of a load that has been detected by a lower-level semiconductor switch which supplies / cuts off power to the load with the first threshold value and the second threshold value, when the current consumption value exceeds the first threshold value, the lower-level controller cuts off the power supply to the load connected to the corresponding lower-level semiconductor switch, and, when the current consumption value exceeds the second threshold value, which is equal to or less than the first threshold value, the lower-level controller notifies the upper-level controller of threshold value exceedance information.

Description

In-vehicle power distribution system

[0001] The present invention relates to a hierarchical in-vehicle power distribution system extending from a battery to a terminal load.

[0002] In the power distribution systems for equipment components in next-generation vehicles, relays and fuses used in power distribution are expected to be replaced with intelligent power devices (IPDs) to address power path fail-operation, predict failures, and perform predictive maintenance. IPDs have basic functions of energizing / shutting off, overcurrent protection and diagnostic functions using thresholds for overtemperature, overvoltage, and shutdown, and voltage / current monitoring functions.

[0003] For example, Patent Document 1 discloses a configuration in which an IPD monitors the current consumption of a load, and the monitoring results are collected in a higher-level electronic control unit (ECU, etc.), thereby calculating the total current consumption value of the load, and when the total current consumption approaches the current capacity of the higher-level electric wire, the IPD is shut off according to the priority of the load.

[0004] JP 2023-14748 A

[0005] Here, consider the case where, to reduce costs, a higher-level wire with a current capacity lower than the total rated current of multiple loads is selected, or an IPD (higher-level IPD) that is mounted on a higher-level electronic control unit and distributes power to lower-level electronic control units is downsized (with a lower rated current). In this case, an IPD connected to a load normally sets its tripping threshold based on the rated current of the connected load, so with only the IPD's tripping threshold, there is a possibility that an overcurrent caused by an abnormality in some of the loads will exceed the current capacity of the higher-level wire.

[0006] For this reason, as described in Patent Document 1, it is necessary to aggregate the current consumption values ​​of the loads at a higher level and constantly monitor whether the current consumption value exceeds the allowable current capacity of the higher-level wires. This requires constantly notifying the higher-level electronic control unit of the current consumption value monitored by the IPD connected to the load, which poses a problem of increased communication volume between the higher-level electronic control unit and the lower-level electronic control unit, as well as increased noise associated with the communication.

[0007] Furthermore, when the upper electronic control unit that aggregates the current consumption values ​​of the loads calculates the sum of the current consumption values, detects whether the rated current threshold of the upper IPD has been exceeded or whether the current capacity of the upper electric wire has been exceeded, and further diagnoses abnormalities in the load from the obtained current consumption values, there is a problem that the amount of calculation and power consumption of the upper electronic control unit increases.

[0008] These two issues are expected to have a greater impact as the number of electrical components (loads) increases with the sophistication of products used in Autonomous Driving (AD) / Advanced Driver Assistance Systems (ADAS), and the number of IPDs connected to loads is on the rise.

[0009] In view of the above circumstances, there has been a demand for an in-vehicle power distribution system that can reduce the amount of communication between a higher-level electronic control unit and a lower-level electronic control unit, as well as the amount of calculations performed by the higher-level electronic control unit.

[0010] In order to solve the above problems, one aspect of the present invention provides an in-vehicle power distribution system in which multiple electronic control units are connected in a hierarchical manner, with multiple loads connected to the lowest level. The upper electronic control unit includes an upper semiconductor switch that supplies or cuts off power to the lower electronic control unit, and an upper controller that controls the upper semiconductor switch. The lower electronic control unit is connected between the upper electronic control unit and the load, and includes a lower semiconductor switch that supplies or cuts off power to the load, and a lower controller that controls the lower semiconductor switch. The lower controller compares the current consumption value of the load detected by the lower semiconductor switch with a first threshold and a second threshold, and if the current consumption value exceeds the first threshold, cuts off the power supply to the load connected to the corresponding lower semiconductor switch, and if the current consumption value exceeds a second threshold (anomaly diagnosis threshold) that is equal to or less than the first threshold, notifies the upper controller of threshold-exceeding information. The upper controller provides the lower controller with information for setting the first threshold and the second threshold according to the state of power distribution of the loads of the vehicle, and receives threshold exceedance information from the lower controller.

[0011] According to at least one aspect of the present invention, it is possible to provide an in-vehicle power distribution system that can reduce the amount of communication between a host electronic control unit and a host electronic control unit, and the amount of calculation by the host electronic control unit. Problems, configurations, and effects other than those described above will become apparent from the following description of the preferred embodiment of the present invention.

[0012] FIG. 1 is a diagram showing an example of the configuration of an in-vehicle power distribution system according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of the hardware configuration of an MCU provided in each ECU of the in-vehicle power distribution system according to the first embodiment of the present invention. FIG. 3 is a diagram showing an example of setting of an upper power supply protection threshold and an abnormality diagnosis threshold stored in an IPD control unit of a higher-level MCU in the first embodiment of the present invention. FIG. 4 is a flowchart showing an example of a procedure for threshold switching processing and a procedure for processing when a current monitor value exceeds a threshold in the first embodiment of the present invention. FIG. 5 is a flowchart showing an example of a procedure for processing taking into account the priority of a load when a current consumption value exceeds the upper power supply protection threshold in the first embodiment of the present invention. FIG. 6 is a flowchart showing an example of a procedure for processing when a current consumption value exceeds the abnormality diagnosis threshold in the first embodiment of the present invention. FIG. 7 is a diagram showing a specific example of the configuration of an in-vehicle power distribution system according to the first embodiment of the present invention. FIG. 8 is a diagram showing a specific example of an upper power supply protection threshold and an abnormality diagnosis threshold stored in the IPD control unit of a higher-level MCU in the first embodiment of the present invention. 10 is a diagram showing an example of setting a threshold value for protecting a higher-level power supply and a threshold value for diagnosing an abnormality stored in an IPD control unit of an n-th lower-level MCU in a second embodiment of the present invention. FIG. 11 is a flowchart showing an example of a procedure for processing when a current monitor value exceeds a threshold value for detecting an operation mode error in a third embodiment of the present invention.

[0013] Hereinafter, examples of modes for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. Three exemplary embodiments will be described. The drawings may be more schematic than the actual configuration for clarity of explanation, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in the claims, the electronic control unit is specifically referred to as an "ECU (Electronic Control Unit)," the controller as an "MCU (Micro Controller Unit)," the semiconductor switch as an "IPD," and the state of power distribution as an "operating mode" (representing the form of power management). However, these names are merely examples and are not intended to limit the interpretation of the present invention.

[0014] In this specification and the accompanying drawings, identical or similar components are given the same reference numerals, and redundant explanations may be omitted or only explanations focusing on the differences may be given. Furthermore, when there are multiple identical or similar components, they may be described using the same reference numerals with different subscripts. Note that when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description. The number of each component may be singular or plural unless otherwise specified.

[0015] In the following embodiment, various information is described in a table format, but the information may be in a data format other than a table format. Also, various names such as "XX information," "XX table," "XX list," and "XX list" are interchangeable.

[0016] First Embodiment First, an onboard power distribution system according to a first embodiment of the present invention will be described with reference to Figures 1 to 9. This embodiment is an example of an onboard power distribution system in which a plurality of ECUs are hierarchically connected, and an IPD control unit is provided in a host ECU (host MCU). This description will cover a method for changing two thresholds, namely, a host power supply protection threshold (Type (1)) and an abnormality diagnosis threshold (Type (2)), of a lower IPD mounted in a lower ECU, and the operation when an abnormality occurs in a load connected to the end and the current consumption value exceeds the threshold.

[0017] [Configuration of an In-Vehicle Power Distribution System] Figure 1 is a diagram showing an example of the configuration of an in-vehicle power distribution system according to a first embodiment of the present invention. The in-vehicle power distribution system 1 shown in Figure 1 is configured such that a battery 10, a host ECU 20, subordinate ECUs 30-1 to 30-n, and terminal loads 40-1 to 40-n are hierarchically connected. The host ECU 20 includes a host IPD 21 that supplies / cuts off power to the subordinate ECUs 30-1 to 30-n, and a host MCU (Micro-Control Unit) 22 that controls the operation of the host IPD 21.

[0018] The host MCU 22 includes an IPD control unit 23. The IPD control unit 23 issues necessary instructions 30a-1 to 30a-n to the subordinate MCUs 32-1 to 32-n of the subordinate ECUs 30-1 to 30-n to control the operation of the subordinate IPDs 31-1 to 31-n installed in the subordinate ECUs 30-1 to 30-n. The instructions 30a-1 to 30a-n are instructions to change two thresholds, the host power supply protection threshold and the abnormality diagnosis threshold, and / or instructions to supply / cut off power to the subordinate IPDs 31-1 to 31-n. The host MCU 22 also monitors the current consumption value of the load using the host IPD 21 and issues instructions to supply / cut off power to the host IPD 21. When the subordinate IPD is turned on, power is supplied to the load, and when the subordinate IPD is turned off, power is cut off.

[0019] Each of the subordinate ECUs 30-1 to 30-n includes a subordinate IPD 31-1 to 31-n that supplies or cuts off power to the loads 40-1 to 40-n connected downstream, and a subordinate MCU 32-1 to 32-n that controls the operation of the subordinate IPDs 31-1 to 31-n. The subordinate MCUs 32-1 to 32-n compare the current consumption values ​​of the loads 40-1 to 40-n monitored by the subordinate IPDs 31-1 to 31-n with the two thresholds. If the current consumption value exceeds either threshold, the subordinate MCU 32-1 to 32-n transmits a threshold exceedance flag 30b-1 to 30b-n to the host MCU 22 of the host ECU 20.

[0020] As an example, the subordinate ECU 30-1 includes subordinate IPDs 31-1 to 31-4 and a subordinate MCU 32-1. The subordinate IPD 31-1 has one end connected to the load 40-1 and the other end connected to the host IPD 21, and supplies / cuts off power to the load 40-1. The subordinate IPD 31-3 has one end connected to the subordinate IPD 31-2 and the other end connected to the host IPD 21, and supplies / cuts off power to the load 40-2. The subordinate IPD 31-4 has one end connected to the subordinate IPD 31-2 and the other end connected to the host IPD 21, and supplies / cuts off power to the load 40-3. The subordinate IPD 31-2 has one end connected to the subordinate IPDs 31-3 and 31-4 and the other end connected to the host IPD 21, and supplies / cuts off power to the subordinate IPDs 31-3 and 31-4. The subordinate MCU 32-1 monitors the current consumption values ​​of the loads 40-1 to 40-3 through the subordinate IPDs 31-1 to 31-4, and controls the power supply / cutoff of the subordinate IPDs 31-1 to 31-4 based on the monitoring results.

[0021] As an example, the subordinate ECU 30-n includes a subordinate IPD 31-n and a subordinate MCU 32-n. One end of the subordinate IPD 31-n is connected to a load 40-n, and the other end is connected to the subordinate IPD 21, and supplies / cuts off power to the load 40-n. The subordinate MCU 32-n monitors the current consumption value of the load 40-n through the subordinate IPD 31-n, and controls the supply / cut-off of power to the subordinate IPD 31-n based on the monitoring result.

[0022] In FIG. 1, the lower ECUs 30-1 to 30-n are denoted as "lower ECU_1" to "lower ECU_N." In addition, in the upper ECU 20, the upper IPD 21 is denoted as "IPD_1." Furthermore, in the upper ECU 20, the upper MCU 22 is denoted as "MCU_1." Furthermore, in the lower ECUs 30-1 to 30-n, the lower IPDs 31-1 to 31-n are denoted as "IPD_2" to "IPD_N." N=n+1. Furthermore, in the lower ECUs 30-1 to 30-n, the lower MCUs 32-1 to 32-n are denoted as "MCU_2" to "MCU_N." N=n+1. Furthermore, the loads 40-1 to 40-n are denoted as "load 1" to "load n."

[0023] [Hardware Configuration of ECU] Here, the hardware configuration of the MCUs provided in the upper ECU 20 and the lower ECUs 30-1 to 30-n of the in-vehicle power distribution system 1 will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of the hardware configuration of each ECU provided in the in-vehicle power distribution system 1. The example shown in FIG. 2 can be considered to correspond to the hardware configuration of the MCU mounted in each ECU. The calculator 50 is an example of hardware used as a computer. In the MCU of each ECU shown in FIG. 1, the calculator 50 (computer) executes a program to realize the function of the MCU of each ECU. This realizes power distribution control performed by the ECUs in cooperation with each other.

[0024] The computer 50 includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, and a RAM (Random Access Memory) 53, all connected to a system bus. The computer 50 further includes a non-volatile storage 54 and a communication interface 55.

[0025] The CPU 51 reads out program code of software that realizes each function according to this embodiment from the ROM 52, loads it into the RAM 53, and executes it. Variables, parameters, etc. generated during the calculation processing of the CPU 51 are temporarily written to the RAM 53, and these variables, parameters, etc. are read out as appropriate by the CPU 51. The CPU 51 executes the program code read out from the ROM 52, thereby realizing the function of the MCU of each ECU. However, another processor such as an MPU (Micro Processing Unit) may be used instead of the CPU 51.

[0026] The nonvolatile storage 54 is an example of a recording medium, and is capable of storing data used by a program, data obtained by executing a program, and the like. For example, the nonvolatile storage 54 of the upper MCU 22 stores a setting table 60 (see FIG. 3 ) that registers a threshold value for upper power supply protection (Type (1)) and a threshold value for abnormality diagnosis (Type (2)). The nonvolatile storage 54 may also store an operating system (OS) and programs executed by the CPU 51. The nonvolatile storage 54 may be a hard disk drive (HDD), a solid state drive (SSD), an optical or magnetic disk medium, a semiconductor memory card, or the like.

[0027] A communication device such as a network interface card (NIC) is used as the communication interface 55. The communication interface 55 can transmit and receive various data to and from an external device via a communication network such as a CAN or a dedicated line connected to a terminal of the NIC. The external device can be, for example, an MCU or sensor of another ECU, or a communication device capable of communicating via OTA (Over The Air).

[0028] [Setting of Upper Power Supply Protection Threshold and Abnormality Diagnosis Threshold] Here, the setting of the upper power supply protection threshold and the abnormality diagnosis threshold stored in the IPD control unit 23 of the upper MCU 22 will be described with reference to Fig. 3. Fig. 3 is a diagram showing a setting table 60 for the upper power supply protection threshold and the abnormality diagnosis threshold stored in the IPD control unit 23.

[0029] In the setting table 60 shown in FIG. 3, two thresholds, a higher-level power supply protection threshold (Type (1)) and an abnormality diagnosis threshold (Type (2)) linked to an operation mode, are set for each of the lower-level IPDs 31-1 to 31-n (IPD_2 to N). For example, the setting table 60 is stored in a memory (an example of a storage unit) (not shown) provided in the IPD control unit 23. The memory of the IPD control unit 23 can be considered to be substantially a memory mounted in the MCU. For example, the ROM 52, RAM 53, or non-volatile storage 54 shown in FIG. 2 can be used as the memory.

[0030] In recent years, power saving has become an issue due to the increase in electrical equipment (loads) associated with the sophistication of AD / ADAS products. One method of power saving is to switch the vehicle's operating mode depending on the vehicle's state, external conditions, etc., and supply the necessary power only to the necessary loads 40-1 to 40-n when necessary. The current consumption values ​​of the loads 40-1 to 40-n vary depending on the switching of the operating mode. Therefore, the upper MCU 22 issues an instruction to change the two thresholds to the lower MCUs 32-1 to 32-n, thereby setting optimal thresholds suited to the vehicle's state. Note that information such as thresholds written in memory is determined during initial design, but may be updated via OTA depending on the vehicle's state.

[0031] The upper power supply protection threshold (Type (1)) is set so that the sum of the upper power supply protection thresholds set in the lower IPDs 31-1 to 31-n (in operation mode A: Th1.A-2 + Th1.A-3 + ... + Th1.A-N) falls within the rated current of the upper IPD 21 and the allowable current of the upper electric wires 20a of the lower ECUs 30-1 to 30-n. If an abnormality occurs in some of the loads 40-1 to 40-n and current consumption increases, by shutting off the corresponding lower IPDs 31-1 to 31-n, the sum of the current consumptions of the loads 40-1 to 40-n falls below the rated current of the upper IPD 21 and the allowable current of the upper electric wires 20a of the lower ECUs 30-1 to 30-n. This eliminates the need to shut off the power supply to the upper IPD 21, allowing it to continue supplying power to other normal loads.

[0032] As described above, the abnormality diagnosis threshold (Type(2)) can be set to a threshold appropriate for the vehicle state (power distribution pattern based on the operating mode). This allows for easy diagnosis of abnormalities and signs of failure in the loads 40-1 to 40-n using a threshold appropriate for the vehicle state. The abnormality diagnosis threshold (Type(2)) usually takes a value equal to or less than the upper power supply protection threshold (Type(1)). Desirably, the abnormality diagnosis threshold (Type(2)) should be a value smaller than the upper power supply protection threshold (Type(1)). The abnormality diagnosis threshold (Type(2)) may be used to detect signs of failure before the lower IPDs 31-1 to 31-n are shut off due to an excess of the upper power supply protection threshold (Type(1)).

[0033] [Processing for Switching Threshold Values ​​and Processing When a Monitored Current Value Exceeds a Threshold Value] Next, processing for switching threshold values ​​and processing when a monitored current value exceeds a threshold value performed by the in-vehicle power distribution system 1 will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of the procedure for switching threshold values ​​and processing when a monitored current value exceeds a threshold value performed by the in-vehicle power distribution system 1. The processing of this flowchart is performed by a calculator 50 (computer) executing a program.

[0034] While the vehicle is traveling, the IPD control unit 23 of the host MCU 22 in the host ECU 20 determines whether or not there is an operation mode change (step S100). If an operation mode change is necessary (YES in step S100), the IPD control unit 23 reads two threshold values ​​corresponding to the operation mode after the change from memory and instructs the subordinate MCUs 32-1 to 32-n of the subordinate ECUs 30-1 to 30-n to change the threshold values ​​(step S101).

[0035] Next, in the subordinate ECUs 30-1 to 30-n, the subordinate MCUs 32-1 to 32-n compare the changed thresholds with the current consumption values ​​(current monitor values) monitored by the subordinate IPDs 31-1 to 31-n (step S102). For example, in the case of the subordinate IPD 31-1 (IPD_2), when the operation mode is switched to A, the subordinate MCU 22 reads from memory two thresholds, the upper power supply protection threshold "Th1.A-2" and the abnormality diagnosis threshold "Th2.A-2" associated with the operation mode A, and notifies the lower MCU 32-1 of the two thresholds. The subordinate MCU 32-1 then compares the current consumption value monitored by the subordinate IPD 31-1 (IPD_2) with the upper power supply protection threshold "Th1.A-2" and the abnormality diagnosis threshold "Th2.A-2."

[0036] If switching of the operating mode is not required (NO judgment in step S100), the subordinate MCUs 32-1 to 32-n continue to compare the current consumption value monitored by the subordinate IPDs 31-1 to 31-n with the two threshold values ​​already set in the subordinate MCUs 32-1 to 32-n (step S102).

[0037] After step S102 is completed, the subordinate MCUs 32-1 to 32-n compare the current consumption value monitored by the subordinate IPDs 31-1 to 31-n with the two thresholds to determine whether the current consumption value exceeds the thresholds (step S103). If the thresholds are not exceeded (NO in step S103), the subordinate MCUs 32-1 to 32-n return to the determination process in step S100 and determine whether the operating mode should be switched.

[0038] If the threshold is exceeded (YES in step S103), the slave MCUs 32-1 to 32-n determine whether the threshold that the current consumption value has exceeded is the abnormality diagnosis threshold (step S104).

[0039] If the threshold value that the current consumption value has exceeded is the abnormality diagnosis threshold value (Type (2)) (YES determination in step S104), the corresponding subordinate MCU 32-1 to 32-n notifies the upper MCU 22 of the abnormality (step S105). That is, the corresponding subordinate MCU 32-1 to 32-n notifies the upper MCU 22 of the threshold excess flag 30b-1 to 30b-n for the abnormality diagnosis threshold value.

[0040] If the threshold value that the current consumption value exceeds is not the abnormality diagnosis threshold value, that is, if the corresponding threshold value is the upper power supply protection threshold value (Type (1)) (NO in step S104), the corresponding lower MCU 32-1 to 32-n shuts off the corresponding lower IPD 31-1 to 31-n (step S106). This stops the power supply to the load whose current consumption value exceeds the upper power supply protection threshold value. After step S105 or S106 is completed, the series of processes ends.

[0041] At this time, the corresponding lower MCUs 32-1 to 32-n may notify the upper MCU 22 of the over-threshold flags 30b-1 to 30b-n for the upper power supply protection thresholds, thereby enabling the upper MCU 22 to recognize that the lower IPD is shut off by the lower MCU in the lower ECU.

[0042] [Processing When Current Consumption Value Exceeds Upper Power Supply Protection Threshold] Next, processing that takes into account the priority of a load when the monitored current consumption value (current monitor value) exceeds the upper power supply protection threshold will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the procedure for processing that takes into account the priority of a load when the current consumption value exceeds the upper power supply protection threshold.

[0043] First, when the current consumption value of a load exceeds the upper power supply protection threshold (Type (1)) (corresponding to a NO determination in step S104), the subordinate MCUs 32-1 to 32-n determine whether the priority of the load 40-1 to 40-n connected to the corresponding subordinate IPD 31-1 to 31-n is high (step S200). Whether the priority of a load is high is determined by comparing the priority with a predetermined value. As an example, priority information of the loads 40-1 to 40-n is read from the memory of the upper MCU 22 and stored in the memory of each of the subordinate MCUs 32-1 to 32-n. Note that a cloud environment can also be used to store information such as thresholds and priorities.

[0044] If the priority of the load is low (NO in step S200), the subordinate MCUs 32-1 to 32-n shut off the subordinate IPDs 31-1 to 31-n connected to the corresponding load (step S206). As described above, the corresponding subordinate MCUs 32-1 to 32-n may notify the upper MCU 22 of the over-threshold flags 30b-1 to 30b-n for the upper power supply protection thresholds. After step S206 is completed, this process ends.

[0045] On the other hand, if the load has a high priority (YES in step S200), the subordinate MCUs 32-1 to 32-n notify the superior MCU 22 that the corresponding load has a high priority (step S201). Next, the IPD control unit 23 of the superior MCU 22 reads out alternative thresholds from memory so that the high-priority load is not shut off. The IPD control unit 23 then instructs the subordinate MCUs 32-1 to 32-n to change the thresholds (the superior power supply protection threshold and the abnormality diagnosis threshold) of the subordinate IPDs 31-1 to 31-n connected to multiple loads, including the high-priority load, to the alternative thresholds (step S202).

[0046] The alternative thresholds, both the upper power supply protection threshold and the abnormality diagnosis threshold, are higher than the original thresholds. Note that the alternative threshold may be only the upper power supply protection threshold. In other words, the IPD control unit 23 of the upper MCU 22 adjusts at least the upper power supply protection thresholds of the multiple lower IPDs 31-1 to 31-n, including the lower IPD connected to the high-priority load, so that the operation of the load can continue.

[0047] As a result, when the current consumption value of a high-priority load exceeds the upper power supply protection threshold, not only is it immediately shut off, but the thresholds for other loads can be adjusted to shut off the other loads while the operation of the high-priority load continues. Alternatively, if the total current consumption value of a plurality of loads does not exceed the current capacity of the upper electric wire 20a, all loads continue to operate, allowing the operation of the high-priority load to continue.

[0048] After receiving the instruction to change the threshold, the subordinate MCUs 32-1 to 32-n determine whether there are any subordinate IPDs 31-1 to 31-n whose current consumption value exceeds the changed threshold (step S203). If there are no subordinate IPDs 31-1 to 31-n whose current consumption value exceeds the changed threshold (NO in step S203), the series of processes ends without shutting off the subordinate IPDs 31-1 to 31-n.

[0049] On the other hand, if there is a lower IPD 31-1 to 31-n whose current consumption value exceeds the changed threshold value (YES judgment in step S203), the corresponding lower MCU 32-1 to 32-n determines whether the changed threshold value whose current consumption value has exceeded is the threshold value for abnormality diagnosis (step S204).

[0050] If the changed threshold value that has been exceeded is the abnormality diagnosis threshold value (YES in step S204), the subordinate MCUs 32-1 to 32-n notify the superior MCU 22 of the threshold value exceedance flags 30b-1 to 30b-n for the changed abnormality diagnosis threshold value (step S205). After step S205 is completed, the series of processes ends.

[0051] If the changed threshold that has been exceeded is not the abnormality diagnosis threshold, that is, if the corresponding threshold is the upper power supply protection threshold (NO in step S204), the corresponding subordinate MCU 32-1 to 32-n returns to the determination process of step S200. Then, the subordinate MCU 32-1 to 32-n determines whether the priority of the load 40-1 to 40-n connected to the corresponding subordinate IPD 31-1 to 31-n is high, and performs the processes of steps S201 to S206 described above depending on the priority of the corresponding load. Note that it is desirable to limit the number of times (for example, once) that the return from step S204 to step S200 is performed from a safety standpoint.

[0052] [Processing When Current Consumption Value Exceeds Abnormality Diagnosis Threshold] Next, processing when the monitored current consumption value (current monitor value) exceeds the abnormality diagnosis threshold will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the procedure for processing when the current consumption value exceeds the abnormality diagnosis threshold.

[0053] In recent years, from the viewpoint of vehicle fail-operation, it has been considered to continue the vehicle's travel to a safe location by using an alternative function (load) when a certain function (load) malfunctions. The flowchart shown in Figure 6 includes a process for checking the operation of the alternative function (load) in advance so that the system can reliably transition to fail-operation control when a certain function (load) malfunctions.

[0054] First, when the current consumption value of the load exceeds the abnormality diagnosis threshold (when a failure sign is detected), the subordinate MCUs 32-1 to 32-n notify the upper MCU 22 of the abnormality (step S300). Here, the corresponding subordinate MCUs 32-1 to 32-n notify the upper MCU 22 of the threshold excess flags 30b-1 to 30b-n corresponding to the abnormality diagnosis threshold.

[0055] Next, the host MCU 22 determines whether or not there is an alternative function (load) that requires a prior operation check for the load 40-1 to 40-n in which the abnormality has occurred (step S301). For example, the correspondence between a certain function (load) and an alternative function (load) is stored in a memory (not shown). Similarly, the correspondence between an alternative function (load) and whether or not a prior operation check is required is stored in the memory. Here, if there is no alternative function (load) that requires a prior operation check for the load 40-1 to 40-n in which the abnormality has occurred (NO determination in step S301), the series of processes ends.

[0056] If the load 40-1 to 40-n in which an abnormality has occurred has an alternative function (load) that requires a prior operation check (YES in step S301), the upper MCU 22 increases the priority of the alternative function (load), changes the two thresholds (upper power supply protection threshold and abnormality diagnosis threshold) of the lower IPDs 31-1 to 31-n connected to the alternative function (load) if necessary, and performs a prior operation check of the alternative function (load) (step S302). In this way, by checking in advance whether the alternative function (load) is operational, the automotive power distribution system 1 can reliably transition to fail-operation control.

[0057] In this embodiment, it is desirable to increase at least one of the priority of the alternative function (load) and the threshold value (Type (1), Type (2)). This allows the automotive power distribution system 1 to reliably transition to fail-operation control.

[0058] For example, as shown in step S202 of FIG. 5, it is possible to increase two thresholds so that the alternative function (load) is not shut off in order to achieve fail-operation. The amount of increase in the thresholds should be set in advance. However, it is also possible to increase only the abnormality diagnosis threshold as the threshold for the alternative function (load). This prevents the current consumption value of the alternative function (load) from exceeding the changed abnormality diagnosis threshold, allowing for a transition to fail-operation control.

[0059] Furthermore, since it is sufficient that the priority of the alternative function (load) is relatively higher than that of the other functions (loads), the priority of the other functions (loads) may be lower than the priority of the alternative function (load). Alternatively, the power supply may be cut off starting from the function with the lowest priority among the other functions (loads).

[0060] Next, the host MCU 22 determines whether it is necessary to notify the details of the failure sign detection and the details of the preliminary operation check of the alternative function (load) to an external party (step S303). The external party may be an automobile dealer, a user, etc. For example, if it is necessary to notify information about these details (hereinafter referred to as an abnormality, etc.) to an external party, this information is set in advance and stored in a memory (not shown).

[0061] If it is necessary to notify the outside of such information on abnormalities, etc. (YES judgment in step S303), the upper MCU 22 notifies the information on abnormalities, etc. via OTA to a terminal installed at the automobile dealer or the vehicle user's terminal, etc. (step S304).

[0062] On the other hand, if there is no need to notify the outside of the information on the abnormality or the like (NO in step S303), or after the process of step S304 is completed, the series of processes is terminated.

[0063] In this way, in the automotive power distribution system according to this embodiment, the upper controller (upper MCU 22) instructs the lower controllers (lower MCUs 32-1 to 32-n) to supply or cut off power to the loads (loads 40-1 to 40-n) based on the threshold exceedance information (threshold exceedance flags 30b-1 to 30b-n) received from the lower controllers.

[0064] [Example 1] For example, consider a case where a vehicle is equipped with a long-distance camera, a medium-distance camera, and a short-distance camera as object detection functions (loads). These cameras may be separate or may be integrated into a triple-lens camera.

[0065] To save power, it is expected that the cameras and functions to be used will be limited (shut off or operating frequency suppressed (intermittent operation)) depending on the vehicle speed, road conditions, etc. For this reason, it is expected that operation modes such as long-distance detection mode and short-distance / medium-distance detection mode will be provided, and that each operation mode will be switched depending on conditions such as vehicle speed. For example, if the amount of power consumption differs depending on the camera or operating state, the abnormality diagnosis threshold of the IPD connected to the camera or operating state will be changed. In the long-distance detection mode, all cameras will be turned ON. In the short-distance / medium-distance detection mode, only the long-distance camera will be turned OFF.

[0066] For example, if the long-range camera fails in long-range detection mode, (Example 1) the long-range range can be covered with another sensor such as LiDAR (Light Detection and Ranging), (Example 2) the long-range range can be covered with a medium-range camera, etc. Also, if the medium-range camera fails in short / medium-range detection mode, (Example 3) the long-range camera can be used to cover the medium-range range.

[0067] [Example of an in-vehicle power distribution system] Here, an example of an in-vehicle power distribution system will be described using a specific example. Fig. 7 is a diagram showing a specific example of the configuration of an in-vehicle power distribution system. Fig. 8 is a diagram showing specific examples of the upper power supply protection threshold (Type (1)) and the abnormality diagnosis threshold (Type (2)) stored in the IPD control unit of the upper MCU.

[0068] 7 is comprised of a host ECU 20 and subordinate ECUs 30-1 and 30-2. The configurations of the host ECU 20 and subordinate ECU 30-1 are the same as those of the host ECU 20 and subordinate ECU 30-1 in the vehicle power distribution system 1 shown in FIG.

[0069] The subordinate ECU 30-2 includes subordinate IPDs 31-5 to 31-6 and a subordinate MCU 32-2. One end of the subordinate IPD 31-5 (IPD_6) is connected to a load 40-4 (load 4), and the other end is connected to the upper IPD 21 of the upper ECU 20 via the upper electric wire 20a. The subordinate IPD 31-5 transmits information on the monitored current consumption value of the load 40-4 to the subordinate MCU 32-2. The subordinate IPD 31-6 (IPD_7) is connected to a load 40-5 (load 5), and the other end is connected to the upper IPD 21 of the upper ECU 20 via the upper electric wire 20a. The subordinate IPD 31-6 transmits information on the monitored current consumption value of the load 40-5 to the subordinate MCU 32-2. The subordinate MCU 32-2 receives instructions 30a-2 from the IPD control unit 23 of the superior MCU 22, including instructions to change two thresholds, the superior power supply protection threshold and the abnormality diagnosis threshold, and instructions to supply / cut off power to the subordinate IPD. The subordinate MCU 32-2 also transmits an over-threshold flag 30b-2 to the IPD control unit 23 of the superior MCU 22 according to the comparison result between the current consumption value and the threshold.

[0070] 8, information is stored in a memory (not shown) provided in the IPD control unit 23, linking the operation mode with two thresholds (a threshold for protecting the upper power supply and a threshold for diagnosing an abnormality) for each IPD. The maximum current consumption of the assumed load is 5 A, and the maximum current consumption (allowable current) allowed in the upper electric wire 20a is 15 A.

[0071] Type (1): Upper power supply protection threshold (IPD_1 ≥ IPD_2 + IPD_4 + IPD_5 + IPD_6 + IPD_7) ⇒ Threshold to prevent the rating of the upper IPD_1 from being exceeded. Type (2): Abnormality diagnosis threshold (Type (1) ≥ Type (2)) ⇒ Threshold to detect early signs of failure.

[0072] As an example, in the setting table 60, the upper power supply protection thresholds (Type (1)) for operation mode A are "2 A" for IPD_2, "5 A" for IPD_4, "3 A" for IPD_5, "2 A" for IPD_6, and "3 A" for IPD_7. Also, the abnormality diagnosis thresholds (Type (2)) for operation mode A are "1.7 A" for IPD_2, "4.5 A" for IPD_4, "2.5 A" for IPD_5, "1.5 A" for IPD_6, and "2.5 A" for IPD_7.

[0073] 8, no threshold value is set for IPD_3, but it goes without saying that two threshold values ​​may be set. For example, by setting a threshold value for IPD_3, it is possible to simultaneously cut off the power supply to IPD_4 and IPD_5 by cutting off IPD_3 according to the comparison result between the current consumption value and the threshold value.

[0074] [Example of when Type (1): upper power supply protection threshold is exceeded at load 5 in operating mode A] (1) An abnormality occurs at load 5 while the load is operating at a total current consumption of 13 A. (2) The current consumption of load 5 increases from 1 A to 4 A, and the shutdown threshold of IPD_7 is 3 A, so IPD_7 shuts off. (3) The shutdown of IPD_7 keeps the total current consumption of the loads below 15 A, so the total current consumption does not exceed the shutdown threshold of IPD_1 (upper IPD), and IPD_1 is not shut off. (4) Since the upper power supply continues, the power supply to normal loads 1 to 4 also continues, preventing loads 1 to 4 from stopping.

[0075] [Example of when Type (2): abnormality diagnosis threshold is exceeded at load 5 in operating mode A] (1) An abnormality occurs in load 5 while the load is operating with a total current consumption of 13 A. (2) The current consumption of load 5 increases from 1 A to 2.7 A. (3) Because the abnormality diagnosis threshold of IPD_7 is 2.5 A, the lower MCU 32-2 notifies the upper MCU 22 of the threshold excess flag 30b-2 for the abnormality diagnosis threshold.

[0076] As described above, the in-vehicle power distribution system (in-vehicle power distribution system 1) according to this embodiment is an in-vehicle power distribution system in which multiple electronic control units are connected hierarchically, with multiple loads connected to the lowest level. The upper electronic control unit (upper ECU 20) includes an upper semiconductor switch (upper IPD 21) that supplies or cuts off power to the lower electronic control units, and an upper controller (upper MCU 22) that controls the upper semiconductor switch. The lower electronic control units (lower ECUs 30-1 to 30-n) are connected between the upper electronic control units and the loads, and include lower semiconductor switches (lower IPDs 31-1 to 31-n) that supply or cut off power to the loads, and lower controllers (lower MCUs 32-1 to 32-n) that control the lower semiconductor switches. The lower-level controller compares the current consumption value of the load detected by the lower-level semiconductor switch with a first threshold and a second threshold, and if the current consumption value exceeds the first threshold (threshold for protecting the upper-level power supply), it cuts off the power supply to the load connected to the corresponding lower-level semiconductor switch, and if the current consumption value exceeds a second threshold (threshold for diagnosing abnormalities) that is equal to or less than the first threshold, it notifies the upper-level controller of threshold-exceeding information (threshold-exceeding flags 30b-1 to 30b-n). The upper-level controller provides the lower-level controller with information for setting the first threshold and the second threshold according to the state of power distribution of the vehicle load (instructions to change the thresholds or notifications of operating modes, which will be described later), and receives threshold-exceeding information from the lower-level controller.

[0077] In addition, in the automotive power distribution system according to this embodiment, the lower electronic control unit includes a plurality of lower semiconductor switches (lower IPDs 31-1 to 31-n), and the first threshold and the second threshold are set for each lower semiconductor switch.

[0078] Furthermore, in the in-vehicle power distribution system according to this embodiment, the upper controller (upper MCU 22) includes a storage unit (memory of the IPD control unit 23). The storage unit stores, for each lower semiconductor switch (lower IPD 31-1 to 31-n), information on the vehicle's power distribution state (operating mode), a first threshold value (threshold value for protecting the upper power supply), and a second threshold value (threshold value for diagnosing an abnormality), in association with each other. In response to switching of the power distribution, the upper controller reads the first threshold value and the second threshold value from the storage unit and notifies the lower controllers (lower MCUs 32-1 to 32-n) of the first threshold value and the second threshold value (instructions 30a-1 to 30a-n).

[0079] In the in-vehicle power distribution system according to this embodiment, the first threshold (higher power supply protection threshold) is set to a threshold that prevents the upper power line from exceeding the allowable current capacity, and the second threshold (abnormality diagnosis threshold) is set to a threshold that can detect load abnormalities according to the vehicle state (power distribution pattern based on the operating mode). As a result, according to this embodiment, even if an abnormality occurs in some loads, such as a sudden increase in current consumption due to the higher power supply protection threshold, the lower IPD connected to the corresponding load is shut off, thereby protecting the allowable current capacity in the upper power line and allowing power supply to other loads to continue. Therefore, it is possible to avoid stopping normal loads. Furthermore, according to this embodiment, the abnormality diagnosis threshold allows current consumption to be diagnosed using a threshold that matches the vehicle state (power distribution pattern based on the operating mode). Therefore, not only failures but also signs of failures can be easily detected (these are functional safety measures and improved reliability).

[0080] Furthermore, in this embodiment, since it is possible to prevent the upper electric wire from exceeding the allowable current capacity, there is no need to make the upper electric wire larger than necessary (for example, by reducing the diameter of the wire harness), and the upper IPD can also be made smaller. By making the upper electric wire and IPD smaller, it is possible to simplify the heat dissipation design. As a result, it is possible to reduce the cost of hardware resources (cost reduction).

[0081] In addition, in this embodiment, the lower ECU determines the current consumption of the load through the lower IPD based on the first threshold (threshold for protecting the upper power supply) and the second threshold (threshold for diagnosing an abnormality), and only a threshold excess flag, a threshold change instruction, or a power supply / cutoff instruction is transmitted and received between the upper ECU (the lower MCU that controls the lower IPD) and the lower ECU. Therefore, in this embodiment, the amount of communication between the lower ECU and the upper ECU and the amount of calculation by the upper ECU are reduced compared to conventional methods, and the above-mentioned effects can be achieved.

[0082] In other words, in this embodiment, regarding the diagnosis of an excess of the current capacity of the upper electric wire and the diagnosis of an abnormality of the load due to current consumption, the lower IPD is shut off or an abnormality is diagnosed when the current consumption value exceeds a threshold value. This eliminates the need for the upper ECU to constantly monitor the current consumption of the load, and makes it possible to reduce the amount of communication between the upper ECU and the lower ECU and noise associated with the communication (reduced communication amount and noise).

[0083] In this embodiment, since the host ECU does not need to collect the current consumption values ​​of the loads from the subordinate ECUs for diagnosis, the host ECU does not perform calculations using the collected current consumption values, which reduces the amount of calculations and power consumption of the host ECU (reduction in calculation amount and power consumption).

[0084] Furthermore, in this embodiment, a failure sign can be detected by determining whether the current consumption value exceeds a threshold for abnormality diagnosis. With this configuration, this embodiment can contribute to a reliable transition to fail-operation control, such as changing the priority and threshold of an alternative function (load) and enabling advance operation check of the alternative function (load). Furthermore, this embodiment can notify the dealer or vehicle user of the abnormality (failure sign, advance operation check of the alternative function (load)) via OTA, enabling early vehicle maintenance.

[0085] Second Embodiment Next, an in-vehicle power distribution system according to a second embodiment of the present invention will be described with reference to Figures 9 to 11. This embodiment is an example of an in-vehicle power distribution system in which a plurality of ECUs are hierarchically connected, and an IPD control unit is provided in a lower MCU. Here, we will explain how to change two thresholds, the upper power supply protection threshold (Type (1)) and the abnormality diagnosis threshold (Type (2)), of the lower IPD mounted on the lower ECU, and the operation when an abnormality occurs in a load connected to the end and the current consumption value exceeds the threshold.

[0086] [Configuration of an in-vehicle power distribution system] Figure 9 is a diagram showing an example of the configuration of an in-vehicle power distribution system according to a second embodiment of the present invention. The in-vehicle power distribution system 1A shown in Figure 9 shows a configuration in which IPD control units 33-1 to 33-n are provided in the subordinate MCUs 32-1 to 32-n. The in-vehicle power distribution system 1A has the same basic configuration as the in-vehicle power distribution system 1 in Figure 1, but since the subordinate MCUs 32-1 to 32-n are provided with IPD control units 33-1 to 33-n, the IPD control unit 23 of the superior MCU 22 has been eliminated.

[0087] Here, the upper power supply protection threshold and the abnormality diagnosis threshold are set and changed independently for each of the lower MCUs 32-1 to 32-n (IPD control units 33-1 to 33-n). For this reason, only vehicle operation mode information 30c-1 to 30c-n is notified from the upper MCU 22 to the lower MCUs 32-1 to 32-n. In FIG. 9, the IPD control units 33-1 to 33-n are represented as "IPD control unit 1" to "IPD control unit N."

[0088] [Setting of upper power supply protection threshold and abnormality diagnosis threshold] Here, the setting of the upper power supply protection threshold and abnormality diagnosis threshold stored in the IPD control units 33-1 to 33-n of the lower MCUs 32-1 to 33-n will be described with reference to Figures 10 and 11.

[0089] Fig. 10 is a diagram showing a setting table 70-1 for the upper power supply protection threshold (Type(1)) and the abnormality diagnosis threshold (Type(2)) stored in the IPD control unit 33-1 of the first subordinate MCU 32-1. Fig. 11 is a diagram showing a setting table 70-n for the upper power supply protection threshold (Type(1)) and the abnormality diagnosis threshold (Type(2)) stored in the IPD control unit 33-n of the nth subordinate MCU 32-n.

[0090] As shown in the setting tables 70-1 and 70-n, in this embodiment, a memory is provided in the IPD control units 33-1 to 33-n, and two thresholds, a higher-level power supply protection threshold (Type (1)) and an abnormality diagnosis threshold (Type (2)) linked to the operating mode, are set for each of the lower-level IPDs 31-1 to 31-n (IPD_2 to N).

[0091] 3, all threshold information for the subordinate IPDs 31-1 to 31-n is stored in the host MCU 22 because the IPD control unit 23 is provided in the host MCU 22. However, as shown in the setting tables 70-1 and 70-n in Figures 10 and 11, only threshold information for the subordinate IPDs 31-1 to 31-n mounted in each of the subordinate ECUs 30-1 to 30-n is stored in memory. Figure 10 shows the information stored in the memory of the IPD control unit 33-1, and Figure 11 shows the information stored in the memory of the IPD control unit 33-n.

[0092] The threshold value switching process by the in-vehicle power distribution system 1A and the process when the current monitor value exceeds the threshold value are executed according to the flowchart shown in Fig. 4, as in the first embodiment. However, in the in-vehicle power distribution system 1A, the threshold value switching is determined and executed by the IPD control units 33-1 to 33-n of the subordinate MCUs 32-1 to 32-n, not by the superior MCU 22.

[0093] Therefore, in the in-vehicle power distribution system 1A, when the operating mode is switched (YES in step S100), the IPD control units 33-1 to 33-n of the subordinate MCUs 32-1 to 32-n receive information about the operating mode from the superior MCU 22 and read threshold values ​​from memory based on that information (step S101).Then, the IPD control units 33-1 to 33-n compare the current consumption values ​​of the subordinate IPDs 31-1 to 31-n with the two threshold values ​​(step S102).

[0094] This is just one example, and if there is no need to receive information such as operating mode from the upper MCU 22, the IPD control units 33-1 to 33-n of the lower MCUs 32-1 to 32-n can independently perform threshold switching processing and processing when the threshold is exceeded.

[0095] As described above, in the in-vehicle power distribution system (in-vehicle power distribution system 1A) according to this embodiment, the lower-level controllers (lower-level MCUs 32-1 to 32-n) include a storage unit (memory of the IPD control units 33-1 to 33-n). The storage unit stores, for each lower-level semiconductor switch (lower-level IPD 31-1 to 31-n), information on the vehicle's power distribution state (operating mode), a first threshold value (threshold value for protecting the upper-level power supply), and a second threshold value (threshold value for diagnosing anomalies), in association with each other. The lower-level controller reads and sets the first threshold value and the second threshold value from the storage unit based on information on the power distribution state of the loads provided by the upper-level controller (upper-level MCU 22).

[0096] The use of the in-vehicle power distribution system according to the present embodiment configured as described above eliminates the need for communication of threshold information between the upper MCU of the upper ECU and the lower MCU of the lower ECU. Therefore, this embodiment reduces the amount of communication between the upper MCU and the lower MCU compared to the first embodiment, while enabling the diagnosis of an excess of the current capacity in the upper electric wire and the diagnosis of an abnormality in the load due to current consumption.

[0097] Third Embodiment Next, an in-vehicle power distribution system according to a third embodiment of the present invention will be described with reference to Fig. 12. In this embodiment, an upper power supply protection threshold (Type (1)) is applied to the "load rated current threshold," and an abnormality diagnosis threshold (Type (2)) is applied to the "operation mode misconfiguration detection threshold." Below, a method for changing two thresholds, the load rated current threshold and the operation mode misconfiguration detection threshold, of a lower IPD mounted on a lower ECU when an IPD control unit is provided in the upper ECU in an in-vehicle power distribution system will be described, as well as an operation when the operation mode of a load connected to the end is misconfigured and the current consumption value exceeds the threshold.

[0098] The in-vehicle power distribution system of this embodiment has the same basic configuration as the in-vehicle power distribution system 1 shown in Figure 1, but is designed to be configured in such a way that the total rated current of the loads 40-1 to 40-n does not exceed the current capacity of the upper electric wire 20a.

[0099] In addition, the setting of the two threshold information in this embodiment has the same basic configuration as the setting table 60 including the two threshold information shown in Figure 3, but since the total rated current of the loads 40-1 to 40-n does not exceed the current capacity of the upper electric wire 20a, the value of the rated current of the load is set as the threshold of Type (1).

[0100] The power consumption of the entire vehicle is increasing, and there is a demand for reduction in the power consumption (power saving) of each electrical component (load). For this reason, in this embodiment, it is considered that the operation mode is switched according to the external environment (weather and road conditions), and low-priority sensors are switched to power-saving operation (reduced current consumption).

[0101] For example, the load 40-1 (load 1) is an in-vehicle camera, and operation mode A is used for driving on an ordinary road, and operation mode B is used for driving on an expressway. In this case, when driving on an expressway, there is a greater distance to the vehicle ahead, so intermittent operation (image capture) is sufficient compared to when driving on an ordinary road. Therefore, operation mode B has a longer processing cycle and lower current consumption than operation mode A.

[0102] Suppose that when the subordinate MCU 32-1 controls the operation mode of the load 40-1 (load 1), the subordinate MCU 32-1 mistakenly sets operation mode A instead of operation mode B. In this case, there is a concern that the current consumption of the load 40-1 (load 1) will be higher than expected, which may increase the power consumption of the entire vehicle. Therefore, a threshold value (Type (2)) is set for detecting an erroneous setting of the load operation mode.

[0103] [Processing When Current Consumption Value Exceeds Threshold for Detecting Misconfiguration of Operation Mode] FIG. 12 is a flowchart showing an example of the procedure for processing when the monitored current consumption value (current monitor value) exceeds the threshold for detecting misconfiguration of operation mode.

[0104] First, when the load current consumption value exceeds the threshold for detecting an incorrect setting of the operating mode, the lower MCUs 32-1 to 32-n notify the upper MCU 22 of the operating mode currently set in the lower MCUs 32-1 to 32-n and that the current consumption value has exceeded the threshold for detecting an incorrect setting of the operating mode (step S400).

[0105] Next, the host MCU 22 that has received the notification determines whether there is a difference between the operation mode received from the subordinate MCUs 32-1 to 32-n and the operation mode instructed by the host MCU 22 (step S401). If there is a difference between these operation modes (YES in step S401), the host MCU 22 transmits information about the operation mode to the subordinate MCUs 32-1 to 32-n and instructs them to reset the operation mode (step S402).

[0106] If the determination in step S401 is NO, or after step S402 is completed, the host MCU 22 determines whether or not it is necessary to notify the automobile dealer, the user, etc. of the abnormality in which the operation mode is erroneously set in the subordinate MCUs 32-1 to 32-n (step S403). For example, if it is necessary to notify the outside of such an abnormality, this fact is set in advance and stored in a memory (not shown).

[0107] For example, if there is a difference in the operating mode between the upper MCU 22 and the lower MCUs 32-1 to 32-n, an abnormality in the lower MCUs 32-1 to 32-n or an abnormality in the information transmission between the upper MCU 22 and the lower MCUs 32-1 to 32-n may be suspected. Therefore, in step S403, a confirmation is made as to whether these possible abnormalities should be notified to an external party (such as an automobile dealer or a user). On the other hand, if there is no difference in the operating mode between the upper MCU 22 and the lower MCUs 32-1 to 32-n (NO in step S401), the current consumption of the load is higher than expected, and therefore an abnormality in the load may be suspected. Therefore, in step S403, a confirmation is made as to whether the possible load abnormality should be notified to an external party.

[0108] If it is necessary to notify the abnormality information to the outside (YES judgment in step S403), the upper MCU 22 notifies the abnormality information via OTA to a terminal installed at the automobile dealer or a terminal of the vehicle user, etc. (step S404).

[0109] If there is no need to notify the abnormality information to the outside (NO in step S403), or after the process of step S404 is completed, the series of processes ends.

[0110] As described above, by using the in-vehicle power distribution system according to this embodiment, two threshold values ​​that match the vehicle state (power distribution based on the operating mode) can be set for the lower IPDs 31-1 to 31-n. As a result, this embodiment not only enables supply protection of the upper power supply and detection of load abnormalities as in the first and second embodiments, but also makes it possible to protect the rated current of the load and detect abnormalities in the MCU, for example.

[0111] As described above, the present invention is not limited to the above-described embodiments, and various other modifications and applications are possible without departing from the spirit of the invention as defined in the claims. For example, the above-described embodiments have been described in detail and specifically to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the components described. Furthermore, it is possible to replace part of the configuration of one embodiment with a component of another embodiment. It is also possible to add a component of another embodiment to the configuration of one embodiment. It is also possible to add, replace, or delete other components from part of the configuration of each embodiment.

[0112] Furthermore, some or all of the above-described configurations, functions, processing units, etc. may be implemented in hardware, for example, by designing them as integrated circuits, etc. As the hardware, a broad processor device such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may be used.

[0113] In addition, in this specification, processing steps describing chronological processing include not only processing that is performed chronologically in the order described, but also processing that is not necessarily performed chronologically but is performed in parallel or individually (for example, processing by objects).

[0114] REFERENCE SIGNS LIST 1, 1A...In-vehicle power distribution system, 10...Battery, 20...Host ECU, 21...Host IPD, 22...Host MCU, 23...IPD control unit (host), 20a...Host electric wire, 30-1 to 30-n...Lower ECU, 31-1 to 31-n...Lower IPD, 32-1 to 32-n...Lower MCU, 33-1 to 33-n...IPD control unit (host), 30a-1 to 30a-n...Threshold change instruction and power supply / cut-off instruction, 30b-1 to 30b-n...Threshold excess flag, 30c-1 to 30c-n...Operation mode notification, 40-1 to 40-n...Load, 50...Calculator, 60, 60A, 70-1, 70-n...Setting table

Claims

1. An in-vehicle power distribution system in which a plurality of electronic control units are connected hierarchically, with a plurality of loads connected to the lowest level, wherein the upper electronic control unit comprises an upper semiconductor switch that supplies or cuts off power to the lower electronic control unit, and an upper controller that controls the upper semiconductor switch, the lower electronic control unit is connected between the upper electronic control unit and the load, and comprises a lower semiconductor switch that supplies or cuts off power to the load, and a lower controller that controls the lower semiconductor switch, the lower controller compares the current consumption value of the load detected by the lower semiconductor switch with a first threshold and a second threshold, and if the current consumption value exceeds the first threshold, cuts off the power supply to the load connected to the corresponding lower semiconductor switch, and if the current consumption value exceeds the second threshold that is equal to or less than the first threshold, notifies the upper controller of threshold exceedance information, the upper controller provides the lower controller with information for setting the first threshold and the second threshold according to the state of power distribution of the load in the vehicle, and receives the threshold exceedance information from the lower controller. Automotive power distribution system.

2. The in-vehicle power distribution system according to claim 1, wherein the lower electronic control unit comprises a plurality of the lower semiconductor switches, and the first threshold value and the second threshold value are set for each of the lower semiconductor switches.

3. The automotive power distribution system according to claim 2, wherein the first threshold is set so that the sum of the first thresholds of the plurality of loads is equal to or less than the allowable current capacity of the electric wire between the upper electronic control unit and the lower electronic control unit, and when the current consumption value of the load connected to the lower semiconductor switch exceeds the first threshold, the lower controller controls the lower semiconductor switch to cut off the power supply to the load.

4. The automotive power distribution system according to claim 2, wherein the second threshold is set to be equal to or lower than the first threshold for detecting an abnormality in the load, and when the current consumption value of the load connected to the lower semiconductor switch exceeds the second threshold, the lower controller notifies the upper controller of the threshold exceedance information.

5. The in-vehicle power distribution system according to claim 2, wherein the upper controller comprises a memory unit, wherein the memory unit stores, for each lower semiconductor switch, information on the state of the power distribution of the vehicle and the first threshold value and the second threshold value in association with each other, and the upper controller reads out the first threshold value and the second threshold value from the memory unit in response to switching of the power distribution and notifies the lower controller of the first threshold value and the second threshold value.

6. The automotive power distribution system according to claim 5, wherein, when the current consumption value of the load connected to the lower semiconductor switch exceeds the first threshold and the priority of the load connected to the lower semiconductor switch whose current consumption value has exceeded the first threshold is higher than a predetermined value, the upper controller adjusts at least the first threshold of the plurality of lower semiconductor switches, including the lower semiconductor switch connected to the load, so that the operation of the load with a higher priority can continue.

7. The in-vehicle power distribution system according to claim 5, wherein the upper controller instructs the lower controller to supply or cut off power to the load based on the threshold excess information received from the lower controller.

8. The automotive power distribution system according to claim 7, wherein, when a current consumption value of the load connected to the lower semiconductor switch exceeds the second threshold, the upper controller increases at least one of the threshold and a priority of an alternative load for the load connected to the semiconductor switch that has exceeded the second threshold.

9. The in-vehicle power distribution system according to claim 8, wherein the upper controller, upon receiving the notification of the threshold exceedance information, performs a prior operation check on the alternative load.

10. The automotive power distribution system according to claim 2, wherein the lower controller comprises a memory unit, wherein the memory unit stores, for each lower semiconductor switch, information on the state of power distribution of the vehicle and the first threshold value and the second threshold value in association with each other, and the lower controller reads out and sets the first threshold value and the second threshold value from the memory unit based on information on the state of power distribution of the load provided by the upper controller.

11. The in-vehicle power distribution system according to claim 2, wherein information on the first threshold and the second threshold is updated over the air.

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