Vehicle-mounted power supply network

Abstract

A vehicle-mounted power supply network according to the present invention supplies power to a load mounted on a vehicle via a plurality of nodes in the vehicle, the plurality of nodes including a first node that transmits power and a second node that receives power transmitted from the first node. The first node and the second node are connected through a power line to which power is supplied and a signal line for transmitting information related to power, and the first node and the second node are respectively provided with a current measuring part for measuring the value of current entering and exiting the node through the power line; a current input / output unit for inputting and outputting a current proportional to the current value between the signal line and the node; and a potential measurement unit that measures the potential of the signal line, the signal line is terminated at a termination potential via a resistor, and when the potential of the signal line is different from the termination potential, it is diagnosed that an abnormality has occurred in a certain location in the in-vehicle power supply network.

Description

Technical Field

[0001] The invention relates to a power supply network, in particular to a vehicle-mounted power supply network suitable for electric vehicles. Background Art

[0002] Since the beginning of this century, the electrification of automotive auxiliary equipment such as electric power steering and electric brakes has made progress. In recent years, the electrification of main machines has also been developing, represented by hybrid vehicles and electric vehicles. In addition, autonomous driving is also developing. In the future, even if a car breaks down, it will be required that the car itself will act autonomously and automatically without human intervention. Based on the above background, the high performance and reliability (continuity of operation in the event of a failure) of the on-board power supply network that supports the electrification and automation of the car are required to be improved.

[0003] In order to allow the vehicle power supply network with a multi-stage daisy chain / ring topology via the electronic control units (regional ECUs) configured on the vehicle body to continue to operate when a fault occurs, it is necessary to detect in which section (between which regional ECUs) the fault occurs, cut off and bypass the processing of the section. The "fault" in this manual refers to "power short circuit" where the wiring is short-circuited to the power source, and "ground short circuit" where the wiring is short-circuited to the ground potential (GND).

[0004] In order to identify the section where the fault occurred, a differential current method is disclosed, for example, in Patent Document 1, which detects whether the transmission current and the reception current are consistent on the power transmission side and the reception side of the section. According to this technology, when there is no fault in the section, the transmission current and the reception current are consistent, but when a fault occurs, the transmission current and the reception current are inconsistent, so the occurrence of the fault can be detected. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-90257 Summary of the invention Technical problem to be solved by the invention

[0006] However, in Patent Document 1, since the current is detected by a current transformer and abnormality is determined by a relay, its application range is limited to the mainstream AC current in commercial power supplies and cannot be applied to the mainstream DC current in current vehicle power supply networks.

[0007] The present invention is accomplished in view of the above technical problems, and its object is to provide an on-vehicle power supply network using direct current, which can quickly detect the occurrence of a fault. Technical means for solving technical problems

[0008] In order to achieve the above-mentioned purpose, the vehicle power supply network involved in the present invention supplies power to the load mounted on the vehicle via multiple nodes in the vehicle, and the multiple nodes include a first node that sends power and a second node that receives power sent from the first node. The first and second nodes are connected by a power line that is powered and a signal line that transmits information related to power. The first and second nodes respectively have a current measuring unit that measures the current value entering and leaving the node via the power line; a current input and output unit that inputs and outputs a current proportional to the current value between the signal line and the node; and a potential measuring unit that measures the potential of the signal line. The signal line is terminated at a terminal potential via a resistor. When the potential of the signal line is different from the terminal potential, it is diagnosed that an abnormality has occurred in a certain part of the vehicle power supply network. Effects of the Invention

[0009] According to the present invention, the occurrence of a failure can be detected quickly in an on-vehicle power supply network using a direct current. Other features related to the present invention will become apparent from the description of this specification and the accompanying drawings. In addition, other problems, structures and effects than those described above will be further clarified by the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram showing a basic configuration of an in-vehicle power supply network according to the first embodiment of the present invention. Figure 2 This is a diagram showing an example of the time elapse of the diagnosis performed from the occurrence of a fault in the vehicle-mounted power supply network to the identification of the fault site. Figure 3 It is a graph showing the relationship between the type of failure that occurs and the potential of the sensing line. Figure 4 This is a diagram showing the configuration of an in-vehicle power supply network according to the second embodiment in which the terminal is a Thevenin terminal. Figure 5 This is a diagram showing a configuration in which a Thevenin terminal is built into the ECU 200 - 1 . Figure 6 This is a diagram showing a configuration in which a Thevenin terminal is built into the ECU 200 - 2 . Figure 7 This is a diagram showing the configuration of an in-vehicle power supply network according to a third embodiment in which network communications within the in-vehicle power supply network are multiplexed. Figure 8 This is a graph showing the change in potential when the potential is transmitted using the recessive voltage of CAN. Fig. 9 This is a diagram showing an example of a configuration adopted when a potential is transmitted using a recessive voltage of CAN. Fig.10This diagram shows the configuration of the vehicle-mounted power supply network according to the fourth embodiment in which the power line is branched and the ECU 200 - 3 is added. Fig.11 This is a diagram showing the configuration of the vehicle-mounted power supply network of the fifth embodiment, showing the detailed configuration of the current measuring unit and the current input / output unit. Fig.12 It means in Fig.11 A diagram of the structure of the current amplifier circuit is added to the structure. Fig.13 This is a diagram showing the configuration of an in-vehicle power supply network according to a sixth embodiment in which power supply is made redundant. Fig.14 It is a diagram showing a modified example of the in-vehicle power supply network involved in the sixth embodiment. Fig.15 It is a diagram showing another modified example of the in-vehicle power supply network involved in the sixth embodiment. Fig.16 This is a diagram showing the structure of an in-vehicle power supply network according to the seventh embodiment applied to four ECUs mounted on a vehicle. Fig.17 It means in Fig.16 A graph showing the relationship between the location where a fault occurs and the opening and closing conditions of the switch in a structure. Fig.18 This is a variation of the in-vehicle power supply network involved in the seventh embodiment. Fig.19 This is a diagram showing the structure of an in-vehicle power supply network according to the eighth embodiment applied to four ECUs mounted on a vehicle. Fig. 20 It means in Fig.19 A graph showing the relationship between the location where a fault occurs and the opening and closing conditions of the switch in a structure. Fig.21 This is a variation of the in-vehicle power supply network involved in the eighth embodiment. Fig. 22 This figure shows the types of switches using semiconductors. DETAILED DESCRIPTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] [Example 1] Figure 1 This is a diagram showing a basic configuration of an in-vehicle power supply network according to the first embodiment of the present invention. The vehicle-mounted power supply network 1 involved in the first embodiment supplies power to a load (not shown) mounted on the vehicle from a power source not shown in the figure via a plurality of ECUs. The vehicle-mounted power supply network 1 includes an ECU 200-1 that sends power and an ECU 200-2 that receives power sent from the ECU 200-1. The ECU 200-1 and the ECU 200-2 are connected by a power line 20 for receiving power and a sensing line 21 for transmitting information related to power.

[0013] ECU200-1 includes a current measuring unit 201-1 that measures the current Iout sent through the power line 20; and a current input / output unit 202-1 that allows a current Is1=K×Iout proportional to the measured current Iout to flow through the sensing line 21. Here, K is a specified proportional constant. ECU200-2 also includes: a current measuring unit 203-2 that measures the current Iin received through the power line 20; and a current input unit 204-2 that receives a current Is2=K×Iin proportional to the current Iin from the sensing line 21. Figure 1 In the above, the current flows from ECU 200-1 to ECU 200-2, but conversely, the current may flow from ECU 200-2 to ECU 200-1. In this case, the current flowing through the sensing line 21 is output from the current input unit 204-2 of ECU 200-2 and input to the current input / output unit 202-1 of ECU 200-1. Therefore, these distinctions will not be made later, and they will be collectively referred to as current input / output units.

[0014] The sensing line 21 is terminated at a potential VAG via a resistor R. A potentiometer capable of measuring a potential at any position and a CPU (Central Processing Unit) for controlling the voltage source, ECU, and operation of the potentiometer are connected to the power supply network 1 (not shown).

[0015] Here, let the potential of the sensing line 21 be Vs, and the current flowing through the resistor R be i. i=(VAG-Vs) / R···(1) According to formula (1), we can get Vs=VAG-R×i···(2) According to Kirchhoff's law for the current at point A, i+K×Iout-K×Iin=0···(3) According to formula (3), we can get i=K×Iin-K×Iout···(4) Substituting equation (4) into equation (2), we get Vs=VAG-R×K(Iin-Iout)···(5.

[0016] It can be seen from equation (5) that the potential Vs of the sensing line 21 includes information about the difference between the receiving current and the sending current (Iin-Iout), and the two are equal, that is, when Iin=Iout, Vs=VAG.

[0017] Here, the value of K is set to a range suitable for information sharing with respect to the values ​​of Is1 and Is2 for the actual target Iin and Iout. For example, if K=10 -3 , then relative to the Iin and Iout of several A, the values ​​of Is1 and Is2 are in the range of several mA. If K = 10 -4 , then relative to the tens of A of Iin and Iout, the values ​​of Is1 and Is2 are in the range of several mA. If K = 10 -5 , then the values ​​of Is1 and Is2 are in the range of several mA for Iin and Iout of several hundred A, achieving a range where the noise generated by Is1 and Is2 will not be a problem. The values ​​of VAG and R are set so that the value of Vs is in a range that is easy to measure. For example, when measuring using a circuit with the positive power supply voltage Vcc of the entire circuit set to 5V, it is preferably set to about VAG = Vcc / 2 = 2.5 [V].

[0018] So, at this time, VAG=Vcc / 2···(6) Substituting equation (6) into equation (5), we get Vs=(Vcc / 2)-R×K(Iin-Iout)···(5)'.

[0019] At this time, if R=103, the voltage range becomes Vs=(Vcc / 2)±several V for the current difference (Iin-Iout) of several A.

[0020] As mentioned above, Figure 1 The structure is opposite to that of ECU200-2. When the current flows from ECU200-2 to ECU200-1, the directions (signs) of Iout and Iin are simply opposite, and the above operation is established.

[0021] Figure 2It is a diagram showing an example of the time lapse of the diagnosis performed from the occurrence of a fault in the vehicle power supply network to the determination of the fault location. Specifically, the process of fault occurrence → fault detection → cut-off switching → network communication → determination of the fault location is shown. First, in stage 1, the occurrence of the fault is detected as an abnormality in the potential Vs1 and Vs2 of the sensing line 21 connected to ECU200-1 and ECU200-2. Then, the power line 20 is cut off and switched to prevent and protect the power line 20 and the circuits in ECU200-1 and ECU200-2 from heating, destruction, and fire caused by overcurrent. Next, in stage 2, the potentials Vs1 and Vs2 of the sensing line 21 respectively measured through network communication are exchanged between ECU200-1 and ECU200-2. In this way, by sharing the potentials Vs1 and Vs2 of the sensing line 21 detected by both, as described below, the fault location can be determined in stage 3.

[0022] Figure 3 This is a graph showing the relationship between the type of fault that occurs and the potential of the sensing line, which is used in the diagnosis of determining the fault location in stage 3. The vertical axis is the potential Vs1 of the sensing line 21 measured by ECU200-1, and the horizontal axis is the potential Vs2 of the sensing line 21 measured by ECU200-2. When there is no fault in the vehicle power supply network 1 and everything is normal, both Vs1 and Vs2 take values ​​that are approximately equal to VAG (=Vcc / 2).

[0023] When the power line is short-circuited to the ground, the impedance of the entire system decreases, so the current flowing into the sensing line 21 increases. Therefore, Vs1 and Vs2 both take values ​​greater than Vcc / 2 in region (1). When the power line is short-circuited to the power supply, the impedance of the entire system increases, so the current flowing into the sensing line 21 decreases. Therefore, Vs1 and Vs2 both take values ​​smaller than Vcc / 2 in region (2).

[0024] If the Vs1 detection circuit of ECU200-1 fails, Vs2 in region (3) is approximately equal to Vcc / 2, and Vs1 takes a value different from Vcc / 2. If the Vs2 detection circuit of ECU200-2 fails, Vs1 in region (4) is approximately equal to Vcc / 2, and Vs2 takes a value different from Vcc / 2.

[0025] At a position closer to the ECU 200 - 1 than the position connected to the sensing line 21 , for example, Figure 1When the sensing line is disconnected at point B, since Vs1 is not terminated by resistor R, it is disconnected from Is1 to Vcc, and Vs2 is terminated by resistor R. Therefore, when the current input / output unit 204-2 is driven by a single-side power supply (Vcc to 0V), it is 0V, and when it is driven by a double-side power supply (Vcc to -Vcc), it is -Is2×R (area (5)) which is proportional to Is2. When the potential VAG is closer to the ECU 200-2 side than the position connected to the sensing line 21, for example, Figure 1 When the sensing line is broken at point C, since Vs1 is terminated by resistor R, the value becomes Is1×R which is proportional to Is1. Since Vs2 is not terminated by resistor R, the current input / output unit 204-2 is 0 V when driven by a single-sided power supply (Vcc~0V) and is -Vcc when driven by two power supplies (Vcc~-Vcc) (area (6)).

[0026] According to the principle described above, by simply measuring the potential of the sensing line 21 connected between ECU200-1 and ECU200-2, the location of the fault in the vehicle power supply network 1 using DC current can be quickly determined, and the fault location can be cut off in a manner that bypasses the fault location to protect the entire system.

[0027] [Example 2] Figure 4 1 is a diagram showing the structure of the vehicle power supply network 1 involved in Example 2. The vehicle power supply network 1 involved in this embodiment is different from the vehicle power supply network 1 involved in Example 1 in that the terminal of the sensing line 21 is a Thevenin terminal. In this embodiment, the sensing line 21 is terminated at the ground potential GND and the positive power supply voltage Vcc by a resistor 2R, respectively, thereby becoming a circuit equivalent to terminating at the potential Vcc / 2 with a resistor R according to the Thevenin theorem. According to this embodiment, as shown in Example 1, there is no need to set a power supply (voltage source) for the terminal potential VAG=Vcc / 2 separately from the positive power supply voltage Vcc, so the circuit structure can be simpler.

[0028] exist Figure 4 In the embodiment, although a Thevenin resistor is provided on the sensing line 21 between ECU 200-1 and ECU 200-2, Figure 5 , Figure 6 As shown, the terminal unit may be built into either ECU 200 - 1 or ECU 200 - 2 . Figure 5 This is an embodiment in which the terminal unit is built into the ECU 200-1. Figure 6 This is an embodiment in which the terminal unit is built into the ECU 200 - 2 .

[0029] [Example 3] Figure 71 is a diagram showing the structure of the vehicle-mounted power supply network 1 according to the third embodiment in which internal network communications are multiplexed. In the vehicle-mounted power supply network 1 according to this embodiment, network transceivers 206-1 and 206-2 are built into ECU 200-1 and ECU 200-2, respectively. These network transceivers 206-1 and 206-2 can be used as Figure 2 The communication lines Vs1 and Vs2 described in are used to share between ECU200-1 and ECU200-2 in phase 2.

[0030] As a method for bidirectional communication for sharing Vs1 and Vs2, the following method can be cited. ■Baseband transmission: ●TDMA (Time Division Multiple Access) ■Modulated wave transmission: ●TDMA (Time Division Multiple Access) ●FDMA (Frequency Division Multiple Access) ●CDMA (Code Division Multiple Access)

[0031] Figure 8 , Fig. 9 The diagrams respectively show the change of potential and the structure when the potential Vs is transmitted as the voltage at the recessive state using CAN (Control Area Network) in the network communication using the sensing line 21 using the network transceivers 206-1 and 206-2. The voltage at the recessive state of CAN is usually about 2.5V, but by setting the voltage at the recessive state to Vs, Vs can be shared as Vs1 and Vs2 in the ECU 200-1 and ECU 200-2 connected to the sensing line 21.

[0032] exist Fig. 9 In the dominant state, for the CANH terminals of the CAN transceivers 206-1 and 206-2, the transistor connected to Vcc is turned on, and the transistor connected to the CANL terminal and GND is turned on. In addition, for the CANH terminals of the CAN transceivers 206-1 and 206-2, the transistor connected to Vcc is turned off, and the transistor connected to the CANL terminal and GND is turned off, and the voltage is usually about 2.5V. However, according to the current Is1 from the current input and output unit 202-1, the current Is2 from the current input and output unit 204-2 and the terminal resistance, according to formula (5)', the potential is Vs.

[0033] In this case, if Figure 8 As shown, the differential voltage is less than 0.5V when recessive and exceeds 0.9V when dominant, so Vs can be transmitted without affecting the CAN communication itself.

[0034] According to the present embodiment, the voltage Vs of ECU 200-1 and ECU 200-2 during the recessive state can be used to perform Figure 2 The detection→cut-off switching in phase 1 uses CAN for network communication in phase 2 and for determining the fault location in phase 3.

[0035] [Example 4] Fig.10 This is a diagram showing the structure of the vehicle power supply network involved in the fourth embodiment in which the power line 20 is branched and ECU200-3 is added. Kirchhoff's law about the current entering and exiting ECU200-1, ECU200-2, and ECU200-3 via the sensing line 21 having the same topology as the power line 20 is also valid as Kirchhoff's law about the current entering and exiting ECU200-1, ECU200-2, and ECU200-3 via the power line 20, so in the case of branching as in this embodiment, the action shown in the first embodiment is also valid. In addition, in this embodiment, the case where the power line 20 is branched into two is shown, but even in the case of branching into several lines, Kirchhoff's law about the current entering and exiting from multiple ECUs via the sensing line 21 having the same topology as the power line 20 is also valid as Kirchhoff's law about the current entering and exiting from multiple ECUs via the power line 20, so the action shown in the first embodiment is also valid.

[0036] [Example 5] Fig.11 This is a diagram showing the configuration of the vehicle-mounted power supply network according to the fifth embodiment, showing the detailed configuration of the current measurement units 201 - 1 and 203 - 2 and the current input / output units 202 - 1 and 204 - 2 .

[0037] In the current measuring unit 201-1 and the current input-output unit 202-1, the current Iout output from the ECU 200-1 is measured by the shunt resistor Rsout. At this time, the voltage difference across the shunt resistor Rsout is IoutxRsout. The voltage across the shunt resistor Rsout is connected to the +input terminal and -input terminal of the operational amplifier OA via the input resistor Ri, respectively. The output of the operational amplifier OA is output to the sensing line 21 via another shunt resistor Rso. Here, the shunt resistor Rso is set to measure the output current from the operational amplifier OA, and the voltage difference across the shunt resistor Rso is Is1xRso. The voltage across the shunt resistor Rso is connected to the +input terminal and -input terminal of the operational amplifier OA via the feedback resistor Rf, respectively. Here, considering the potential difference [(Vin+)-(Vin-)] between the +input terminal and the -input terminal of the operational amplifier OA, it becomes (Vin+)-(Vin-)=(Rf×Iout×Rsout-Ri×Is1×Rso) / (Rf+Ri)···(7).

[0038] Here, since the gain of the operational amplifier OA is ideally infinite, it operates in such a way that the voltage outputted from the output terminal becomes (Vin+)-(Vin-)→0. Therefore, if the left side of equation (7) = 0, then Is1=Rf×Iout×Rsout / Ri×Rso···(8) K=Is1 / Iout=Rf×Rsout / (Ri×Rso)···(9).

[0039] The same is true for the current measuring unit 203-2 and the current input / output unit 204-2 on the ECU 200-2 side. K=Is2 / Iin=Rf×Rsin / (Ri×Rso)···(10).

[0040] Fig.12 is Fig.11 Based on the structure shown, an embodiment of a current amplifier circuit is added to the post-stage of the operational amplifier OA. The output current of the operational amplifier OA is usually about 25 mA, but by adding a current amplifier circuit, a current exceeding this current can be output to the sensing line 21. Even in this case, since the output currents Is1 and Is2 are also measured by the shunt resistor Rso and fed back to the operational amplifier OA, the operations shown in equations (7) to (10) are performed.

[0041] [Example 6] Fig.13This is an embodiment of ECU200-1 and 200-2 for implementing the present invention. ECU200-1 is connected to other ECU200-2 via switches SW1 and SW2 and via power line 20, and is further connected to load 40-1 via switch SW11. In addition, it is also connected to control function 210-2 of other ECU200-2 via switch SW12. Control function 210-1 controls switches SW1, SW2, SW11, and SW12 according to the potentials Vs1 and Vs2 of the sensing lines. Control function 210-1 is powered from the connection point of switches SW1 and SW2 and an external power supply via diode OR (DOR). With the power supply structure as described above, power is supplied from an external power supply even when switches SW1 and SW2 are cut off in the event of a fault, so switches SW1, SW2, SW11, and SW12 can continue to be controlled.

[0042] ECU200-2 is also connected to other ECUs through switches SW3 and SW4 and via power line 20, and is further connected to loads 40-3 and 40-4 through switches SW21 and SW22. Control function 210-2 controls switches SW3, SW4, SW21, and SW22 according to the potentials Vs1 and Vs2 of the sensing lines. Control function 210-2 is powered from the connection point of switches SW3 and SW4 and an external power supply (ECU200-1) via diode OR (DOR). With the power supply structure as described above, even if switches SW3 and SW4 are cut off during a fault, power is provided from an external power supply (ECU200-1), so switches SW3, SW4, SW21, and SW22 can continue to be controlled.

[0043] Fig.14 This is an embodiment in which power is supplied to the control function 210-2 in the ECU 200-2 from the power line 20-12 connected to the ECU 200-1 and the power line 20-23 connected to another power source via the diode OR (DOR). With the power supply structure as described above, even if the switches SW3 and SW4 are disconnected in the event of a failure, power is supplied from the power line 20-12 or the power line 20-23, so that the switches SW3, SW4, SW21, and SW22 can continue to be controlled.

[0044] Fig.15 This is an embodiment in which power is supplied to the control function 210-2 in the ECU 200-2 from the connection point of the switches SW3 and SW4 and the external power supply (ECU 200-3) via a diode OR (DOR). With the power supply structure as described above, even if the switches SW3 and SW4 are cut off in the event of a failure, the switches SW3, SW4, SW21, and SW22 can continue to be controlled because power is supplied from the external power supply (ECU 200-3) of a different system from the ECU 200-1 supplied with power via SW3.

[0045] [Example 7] Figure 16 to Figure 22 An embodiment in which the power supply network described above is mounted on a vehicle is shown. Fig.16 This is an embodiment in which power is supplied from power source 100-1 to ECU200-1, power is supplied from power source 100-2 to ECU200-3, ECU200-1 and ECU200-3 are connected via power line 20-13, power is further supplied from ECU200-1 to ECU200-2 via power line 20-12, and power is further supplied from ECU200-3 to ECU200-4 via power line 20-34. In order to simplify the description, only the components that need to be particularly described are marked with reference numerals for description.

[0046] Power is supplied from power source 100-1 to ECU200-1 via switch SW1, power is supplied to ECU200-2 via switch SW2 and power line 20-12, and connected to ECU200-3 via SW9 and power line 20-13. Power is supplied from ECU200-1 to ECU200-2 via switch SW3.

[0047] Power is supplied from power source 100-2 to ECU200-3 via switch SW5, power is supplied to ECU200-4 via SW5 and power line 20-34, and connected to ECU200-1 via switch SW10 and power line 20-13. Power is supplied from ECU200-3 to ECU200-4 via switch SW7.

[0048] Signal lines, namely sensing lines (not shown) for sharing current information are respectively provided on the power lines 20 - 12 , 20 - 13 , and 20 - 34 . Faults in the power lines 20 - 12 , 20 - 13 , and 20 - 34 are detected by the method provided by the present invention.

[0049] The power supply 100-1 is a DC / DC converter, and is connected to a host driving battery and a host (motor / generator) not shown. When the vehicle is a hybrid vehicle, the host is mechanically connected to the engine, and when the vehicle is an electric vehicle, the host driving battery is connected to a charger or a connection terminal of the charger. Normally, the regenerative power from the host driving battery or the host (motor / generator) is converted into an auxiliary driving voltage by the DC / DC converter of the power supply 100-1, and is provided to the ECU 200-1.

[0050] The power supply 100 - 2 is a battery for driving auxiliary machines, and is normally float-charged by the output of the power supply 100 - 1 via the ECU 200 - 1 and the ECU 200 - 3 .

[0051] Fig.17The operation of each switch in this embodiment is shown. Case 0 is when there is no fault (normal), all switches are turned on, and power is supplied to all loads. Power is supplied to the steering ECU 200-5 and the automatic driving ECU 200-6 via the diode OR, and power is also supplied to the electric brake ECU (BK ECU) 200-7 to 200-10 via each switch.

[0052] Case 1 is a case where the power line 20-12 fails. Figures 1 to 3 The principle of the present invention described above detects a fault, switches SW2 and SW3 are turned off, and the power line 20-12 is disconnected. At this time, the power supply to the ECU 200-2 is cut off, and the power supply to the load 40-21 is also cut off.

[0053] Case 2 is a case where a fault occurs in the power line 20-13. According to the principle of the present invention, the fault is detected, switches SW9 and SW10 are turned off, and the power line 20-13 is disconnected. At this time, since the power source 100-2, i.e., the battery, is disconnected from the power source 100-1, floating charging cannot be performed.

[0054] Case 3 is a case where a fault occurs in the power line 20-34. According to the principle of the present invention, the fault is detected, switches SW6 and SW7 are turned off, and the power line 20-13 is disconnected. At this time, the power supply to ECU200-4 is cut off, and the power supply to loads 40-41 and the electric brake ECU (BK ECU) 200-8 and 200-10 of the rear wheels is cut off. At this time, Fig.18 As shown, by connecting the power source 100-2, i.e., the battery, to the ECU 200-4, even if the power line 20-34 fails, power continues to be supplied to the ECU 200-4, the loads 40-41, and the electric brake ECUs (BK ECUs) 200-8 and 200-10 of the rear wheels. Fig.16 As shown, it is preferred that the power source 100 - 2 , ie, a battery, is connected to the ECU 200 - 3 .

[0055] Case 4 is a case where a fault occurs in the power line 100-1. By monitoring the output of the power source 100-1 or detecting a fault through the self-diagnosis function of the power source 100-1, the switch SW1 is turned off and the power source 100-1 is disconnected. At this time, the output of the floating-charged power source 100-2 supplies power to the entire vehicle power supply network.

[0056] Case 5 is a case where a fault occurs in the power line 100-2. By monitoring the output of the power source 100-2 or detecting a fault through the self-diagnosis function of the power source 100-2, the switch SW5 is turned off and the power source 100-2 is disconnected. At this time, the output of the power source 100-1 supplies power to the entire vehicle power supply network.

[0057] [Example 8] Fig.19 is relative to Fig.16 The structure is further an embodiment in which ECU 200 - 2 and ECU 200 - 4 are connected through power line 20 - 24 via switches SW4 and SW8 . Fig. 20 An operation example of the switch SW of this embodiment is shown. Fig. 20 is Fig.17 In addition to the illustrated operation example, a diagram showing control of switches SW4 and SW8 provided at both ends of power line 20-24 is added.

[0058] In the case where there is no faulty part (normal), it is not necessary for all switches to be turned off to supply power to all loads, but in this case there are two options, case 0A and case 0B. As shown in case 0A, when switches SW9 and SW10 are turned on and ECU200-1 and ECU200-3 are connected via power line 20-13, SW4 and SW8 connected to power line 20-24 connecting ECU200-2 and ECU200-4 can be turned on or off. As shown in case 0B, when switches SW4 and SW8 are turned on and ECU200-2 and ECU200-4 are connected via power line 20-24, SW9 and SW10 connected to power line 20-13 connecting ECU200-1 and ECU200-3 can be turned on or off. In the table, "*" means don't care, that is, it can be turned on or off.

[0059] Situations 1 to 3 and Fig.17 The cases shown are the same and the description thereof is omitted.

[0060] In the event of a failure of the power supply 100-1, there are two options, Case 4A and Case 4B. As shown in Case 4A, when switches SW9 and SW10 are turned on and ECU200-1 and ECU200-3 are connected via the power line 20-13, SW4 and SW8 connected to the power line 20-24 connecting ECU200-2 and ECU200-4 can be turned on or off. In addition, as shown in Case 4B, when switches SW4 and SW8 are turned on and ECU200-2 and ECU200-4 are connected via the power line 20-24, SW9 and SW10 connected to the power line 20-13 connecting ECU200-1 and ECU200-3 can be turned on or off. At this time, the output of the power source 100-2 supplies power to the entire vehicle power supply network.

[0061] Similarly, in the case where the power supply 100-2 fails, there are two options for pure cases 5A and 5B. As shown in case 5A, when switches SW9 and SW10 are turned on and ECU200-1 and ECU200-3 are connected through the power line 20-13, SW4 and SW8 connected to the power line 20-24 connecting ECU200-2 and ECU200-4 can be turned on or off. In addition, as shown in case 5B, when switches SW4 and SW8 are turned on and ECU200-2 and ECU200-4 are connected through the power line 20-24, SW9 and SW10 connected to the power line 20-13 connecting ECU200-1 and ECU200-3 can be turned on or off. At this time, the output of the power source 100-1 supplies power to the entire vehicle power supply network.

[0062] Case 6 is a case where a fault occurs in the power line 20-24. According to the principle of the present invention, the fault is detected, switches SW4 and SW8 are turned off, and the power line 20-24 is disconnected. Power is supplied to ECU 200-2 and ECU 200-4 through power lines 20-12 and 20-34, respectively.

[0063] As described above, by connecting ECU200-2 and ECU200-4 via the power line 20-24 via switches SW4 and SW8, even if any one of the power line 20-12, the power line 20-13, and the power line 20-34 fails, power can continue to be supplied to the load. Fig.21 As shown, the diode OR for supplying power from the power source 100 - 2 to the steering ECU 200 - 5 and the automatic driving ECU 200 - 6 can also be omitted.

[0064] In [Embodiment 7], since current flows bidirectionally only to the wiring of the power source 100-2 and the power line 20-13, when the switches SW5, SW9, and SW10 are implemented by semiconductor switches, as shown in FIG. Fig. 22 As shown in (b), it is necessary to connect elements with opposite polarities in order to control the bidirectional current. The other power lines 20-12 and 20-34 have current flowing in a single direction, so the other SWs are as follows. Fig. 22 (a) shows that it can be a single polarity element. In addition, in [Example 8], since the current only flows bidirectionally to the wiring of the power source 100-2 and all the power lines 20-12, 20-13, 20-34, and 20-24, when the switches SW2 to SW10 are implemented by semiconductor switches, as shown in Fig. 22 As shown in (b), it is necessary to connect elements with opposite polarities in order to be able to control bidirectional current.

[0065] According to the embodiments of the present invention described above, the following effects are achieved. (1) The vehicle-mounted power supply network involved in the present invention supplies power to a load mounted on the vehicle via multiple nodes in the vehicle, the multiple nodes include a first node that sends power and a second node that receives power sent from the first node, the first node and the second node are connected by a power line that is powered and a signal line that transmits information related to power, the first node and the second node each have a current measuring unit that measures the value of a current entering and leaving the node via the power line; a current input and output unit that inputs and outputs a current proportional to the current value between the signal line and the node; and a potential measuring unit that measures the potential of the signal line, the signal line terminates at a terminal potential via a resistor, and when the potential of the signal line is different from the terminal potential, it is diagnosed that an abnormality has occurred in a certain part of the vehicle-mounted power supply network.

[0066] By adopting the above configuration, the occurrence of a failure can be detected quickly in the vehicle-mounted power supply network using direct current.

[0067] (2) The current measurement unit and the current input / output unit are composed of an operational amplifier. This allows even a weak current output from the ECU to be reliably detected by amplification.

[0068] (3) The terminal potential and the resistor are formed by the Thevenin terminal. This eliminates the need to provide a power supply for the terminal potential and the positive power supply voltage separately, and can be expected to reduce the size and cost of the entire system.

[0069] (4) The potential measuring section of each of the first node and the second node measures the potential of the signal line on the node side relative to the position where the signal line ends at the terminal potential. Thus, each node can determine at which position of the signal line a fault has occurred.

[0070] (5) The first node and the second node exchange the potential of the signal line measured by each other via the network. Thus, each node can identify the cause of the failure by comparing the potential measured by itself with the received potential.

[0071] (6) When the potentials of the signal lines of the first node and the second node being exchanged are different, it is diagnosed that one of the signal line, the current measuring unit, and the current input / output unit is abnormal. By adopting the configuration of (5), such a diagnosis can be specifically performed.

[0072] (7) The first node and the second node encode the measured potential of the signal line, and superimpose it on the signal line for transmission. By adopting the multiplexed network communication shown in the third embodiment, information can be transmitted efficiently in this way.

[0073] (8) The node is an electronic control unit, and the electronic control unit includes a current measuring unit, a current input / output unit, a first switch for opening and closing the current flowing to the power line connected to the electronic control unit, a second switch for opening and closing the current flowing to the load connected to the electronic control unit, and a control circuit, and the control circuit controls the first switch and the second switch. Thus, the power line or load current supply path diagnosed as having a fault can be immediately cut off, and the power supply network can be quickly protected.

[0074] (9) The control circuit is supplied with power from a plurality of paths. Thus, even if the power supply is cut off from a part of the power supply, the power supply to the control circuit can be continued by appropriately controlling the switching circuit.

[0075] (10) When it is diagnosed that the signal line is abnormal, the control circuit of the electronic control unit connected to the signal line opens the first switch of the electronic control unit. Thus, similar to (9), the power supply network can be quickly protected after the fault is discovered.

[0076] The present invention is not limited to the above-mentioned embodiments, but also includes various variations. For example, the above-mentioned embodiments are detailed descriptions for the convenience of explaining the present invention, and the present invention is not limited to having all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments. In addition, the structure of other embodiments can also be added to the structure of a certain embodiment. In addition, a part of the structure of each embodiment can be deleted or added / replaced with other structures. Description of symbols

[0077] 20 ... power line, 21 ... sensing line, 40 ... load, 100 ... power source, 200 ... node (electronic control unit: ECU), 201, 203 ... current measuring unit, 202, 204 ... current input and output unit, 210 ... control function (control circuit).

Claims

1. A vehicle-mounted power supply network that supplies power to a load mounted on the vehicle via a plurality of nodes in the vehicle, wherein the vehicle-mounted power supply network is characterized in that: The plurality of nodes include a first node that sends power and a second node that receives power sent from the first node. The first node and the second node are connected via a power line for supplying power and a signal line for transmitting information related to the power. The first node and the second node each have a current measuring unit for measuring a current value entering and exiting the node via the power line; a current input / output section for inputting and outputting a current proportional to the current value between the signal line and the node; and a potential measuring section for measuring the potential of the signal line, The signal line is terminated at a terminal potential via a resistor, and when the potential of the signal line is different from the terminal potential, it is diagnosed that an abnormality has occurred in a certain part of the vehicle-mounted power supply network.

2. The vehicle-mounted power supply network according to claim 1, characterized in that: The current measuring unit and the current input / output unit are formed of operational amplifiers.

3. The vehicle-mounted power supply network according to claim 1, characterized in that: The terminal potential and the resistor are formed by a Thevenin terminal.

4. The vehicle-mounted power supply network according to claim 1, characterized in that: The potential measuring section of each of the first node and the second node measures the potential of the signal line on the side of the node relative to the position where the signal line ends at the terminal potential.

5. The vehicle-mounted power supply network according to claim 4, characterized in that: The first node and the second node exchange the potential of the signal line measured by each other via a network.

6. The vehicle-mounted power supply network according to claim 5, characterized in that: When the potentials of the signal lines of the first node and the second node that are exchanged are different, it is diagnosed that one of the signal line, the current measurement unit, and the current input / output unit is abnormal.

7. The vehicle-mounted power supply network according to claim 5, characterized in that: The first node and the second node encode the measured potential of the signal line, and transmit the encoded potential by superimposing it on the signal line.

8. The vehicle-mounted power supply network according to claim 1, characterized in that: The node is an electronic control unit, The electronic control unit includes: the current measuring unit, the current input / output unit, a first switch for opening and closing the current of the power line connected to the electronic control unit, a second switch for opening and closing the current of the load connected to the electronic control unit, and a control circuit. The control circuit controls the first switch and the second switch.

9. The vehicle-mounted power supply network according to claim 8, characterized in that: The control circuit provides power from a plurality of paths.

10. The vehicle-mounted power supply network according to claim 8, characterized in that: When it is diagnosed that an abnormality has occurred in the signal line, the control circuit of the electronic control unit connected to the signal line opens the first switch of the electronic control unit.

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