ENERGY DISTRIBUTION DEVICE

Abstract

A power distribution device is provided: a first and a second power distribution device. The first power distribution device comprises: a first shutdown unit; and a first control unit that controls the first shutdown unit based on a first shutdown characteristic. The second power distribution device comprises: a second shutdown unit; and a second control unit that controls the second shutdown unit based on a second shutdown characteristic. The first shutdown characteristic and the second shutdown characteristic are initially set such that the first shutdown time is longer than the second shutdown time.The first control unit performs a shutdown characteristic change process of modifying the first shutdown characteristic such that the first shutdown time is longer than the second shutdown time when the onboard device is modified or added and the second shutdown characteristic is changed and the first shutdown time is shorter than the second shutdown time.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a power distribution device. STATE OF THE ART

[0002] There is an on-board power distribution device having a function of distributing power from a power source to a plurality of on-board devices, which is intended to cope with an additional connection of a new on-board device (see, for example, JP2023-014748 A and JP2022-000363 A).

[0003] In the power distribution device described in JP2023-014748 A, conditions are set for a smoke emission characteristic of an electric wire on an upstream side, a melting characteristic of a fuse on the upstream side, and a power control characteristic of a switch on a downstream side. When a sum of currents flowing through a plurality of on-board devices approaches the power control characteristic of the downstream side switch, power allocation to the on-board devices is adjusted according to priority. In a power distribution device described in JP2022-000363 A, an extension section with a fuse is provided in a relay device to which a main line power wiring is connected, and a relay device is further connected via the extension section.

[0004] In the power distribution device described in JP2023-014748 A, the operation of an on-board device with a low priority is sacrificed compared to an on-board device with a high priority. In the power distribution device described in JP2022-000363 A, it is necessary to change the extension section in the relay device each time an on-board device is added or changed, which increases the burden of designing a power protection function.In the power distribution device described in JP2022-000363 A, in a situation where a plurality of relay devices are connected in series or parallel, when an on-board device on a downstream side is added or changed, a condition for electrical wire protection is not met not only in a relay device on the downstream side but also in a relay device on the upstream side. In this case, problems such as simultaneous opening or erroneous opening of a switch or fuse on the upstream side and a switch or fuse on the downstream side occur. SUMMARY OF THE INVENTION

[0005] The present disclosure is intended to provide a power distribution device capable of establishing electric wire protection from an upstream side to a downstream side without requiring redesign of an electric wire protection function when an on-board device is changed or added.

[0006] According to an illustrative aspect of the present disclosure, a power distribution device comprises: a first power distribution device configured to distribute power supplied from a power supply device; and a second power distribution device configured to distribute power distributed from the first power distribution device to an on-board device.The first power distribution device includes: a first disconnection unit configured to connect or disconnect a first electric wire that supplies power from the power supply device to the second power distribution device; and a first control unit configured to control the first disconnection unit based on a first disconnection characteristic indicating a relationship between a heat amount of the first electric wire and a first disconnection time, which is a time from a start of power supply to the first electric wire to the disconnection of the first disconnection unit.The second power distribution device includes: a second disconnection unit configured to connect or disconnect a second electric wire that supplies power from the first power distribution device to the on-board device; and a second control unit configured to control the second disconnection unit based on a second disconnection characteristic indicating a relationship between a heat amount of the second electric wire and a second disconnection time, which is a time from a start of power supply to the second electric wire to the disconnection of the second disconnection unit. The first disconnection characteristic and the second disconnection characteristic are initially set such that the first disconnection time is longer than the second disconnection time.The first control unit executes a first shutdown characteristic changing process of changing the first shutdown characteristic such that the first shutdown time is longer than the second shutdown time when the on-board device is changed or added and the second shutdown characteristic is changed and the first shutdown time is shorter than the second shutdown time.

[0007] According to the present disclosure, electric wire protection can be established from an upstream side to a downstream side without requiring redesign of an electric wire protection function when an on-board device is changed or added. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a power distribution device according to an embodiment of the present disclosure. Fig. 2 is a graph showing a relationship between an energy supply time and a change in a heat amount of an electric wire. Fig. 3 is a logarithmic graph showing a relationship between an exciting current of an electric wire and a cut-off time of a cut-off unit. Fig. 4 is a flowchart showing a process for changing a shutdown characteristic of a shutdown unit on an upstream side after an on-board load on a downstream side is changed or added. DESCRIPTION OF THE EMBODIMENTS

[0008] Hereinafter, the present disclosure will be described with reference to a preferred embodiment. The present disclosure is not limited to the embodiment shown below, and the embodiment shown below can be appropriately changed within a scope that does not deviate from the spirit of the present disclosure. In the embodiment to be described below, some configurations may not be described or shown in the drawings, and for details of the omitted techniques, publicly known or well-known techniques are appropriately applied as long as there is no contradiction with the contents to be described below.

[0009] Fig. 1 is a block diagram showing a power distribution device 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the power distribution device 10 includes a first power distribution device 11, a second power distribution device 12, and a third power distribution device 13. The power distribution device 10 distributes power supplied from an on-board power supply device 1 to a plurality of on-board devices (on-board loads 2A, 2B, 2B', 2C, sensors 3A, 3C, an electronic control unit (ECU) 4, and the like).

[0010] The power supply device 1 is a storage battery such as a lithium-ion battery, a power converter such as a direct current (DC / DC) converter, and a generator such as an alternator. The on-board loads 2A, 2B, 2B', and 2C are motors, air conditioners, lighting devices, and the like. The sensors 3A and 3C are various on-board sensors such as a camera, a lidar (light detection and ranging) (LiDAR), a millimeter-wave radar, an ultrasonic sensor, a global positioning system (GPS) sensor, an acceleration and gyro sensor, a wheel speed sensor, and an air pressure sensor. The ECU 4 is an electronic control device including a microcomputer, a CAN (control area network) bus transceiver, an AD converter, and the like.

[0011] The first power distribution device 11 is connected to the power supply device 1 by an electrical wire 14. The second power distribution device 12 is connected to the first power distribution device 11 by an electrical wire 15. The third power distribution device 13 is connected to the first power distribution device 11 by an electrical wire 16. That is, the second power distribution device 12 and the third power distribution device 13 are connected to the power supply device 1 via the first power distribution device 11.

[0012] The on-board load 2A is connected to the first power distribution device 11 by an electric wire 17A. The sensor 3A is connected to the first power distribution device 11. The on-board load 2B is connected to the second power distribution device 12 by an electric wire 17B. The ECU 4 is connected to the second power distribution device 12. The on-board load 2C is connected to the third power distribution device 13 by an electric wire 17C. The sensor 3C is connected to the third power distribution device 13.

[0013] Here, there is a case where the on-board devices connected to the first to third power distribution devices 11 to 13 are changed or added after delivery of a vehicle, for example, the on-board load 2B connected to the second power distribution device 12 is changed to the on-board load 2B' after delivery of the vehicle. In this case, characteristics of an electric wire protection function of the first to third power distribution devices 11 to 13 are automatically changed. This point will be described in detail later.

[0014] The first power distribution device 11 comprises a shutdown unit 111, a detection unit 112, and a control unit 113. The second power distribution device 12 comprises a shutdown unit 121, a detection unit 122, and a control unit 123. The third power distribution device 13 comprises a shutdown unit 131, a detection unit 132, and a control unit 133.

[0015] The disconnection units 111, 121, and 131 are relays such as semiconductor relays and mechanical relays. The disconnection unit 111 connects or disconnects the electrical wire 14 and the electrical wire 15, and connects or disconnects the electrical wire 14 and the electrical wire 16. The disconnection unit 121 connects or disconnects the electrical wire 15 and the electrical wire 17B. The disconnection unit 131 connects or disconnects the electrical wire 16 and the electrical wire 17C.

[0016] The sensor 3A is connected to a contact on an upstream side of the shutdown unit 111. Therefore, when the shutdown unit 111 is in a disconnected state, the sensor 3A is supplied with power from the power supply device 1. The ECU 4 is connected to a contact on an upstream side of the shutdown unit 121. Therefore, when the shutdown unit 121 is in a disconnected state and the shutdown unit 111 is in a connected state, the ECU 4 is supplied with power from the power supply device 1. The sensor 3C is connected to a contact on an upstream side of the shutdown unit 131. Therefore, when the shutdown unit 131 is in a disconnected state and the shutdown unit 111 is in a connected state, the sensor 3C is supplied with power from the power supply device 1.

[0017] On the other hand, the on-board load 2A is connected to a contact on a downstream side of the disconnect unit 111 through the electric wire 17A. Therefore, when the disconnect unit 111 is in a disconnected state, power is not supplied from the power supply device 1 to the on-board load 2A. The on-board load 2B is connected to a contact on a downstream side of the disconnect unit 121 through the electric wire 17B. Therefore, when the disconnect unit 121 is in a disconnected state, power is not supplied from the power supply device 1 to the on-board load 2B regardless of a state of the disconnect unit 111. The on-board load 2C is connected to a contact on a downstream side of the disconnect unit 131 through the electric wire 17C.Therefore, when the shutdown unit 131 is in a disconnected state, power is not supplied from the power supply device 1 to the on-board load 2C regardless of a state of the shutdown unit 111. .

[0018] The detection unit 112 detects a voltage and a current of the shutdown unit 111 and transmits the detected values ​​to the control unit 113. The detection unit 122 detects a voltage and a current of the shutdown unit 121 and transmits the detected values ​​to the control unit 123. The detection unit 132 detects a voltage and a current of the shutdown unit 131 and transmits the detected values ​​to the control unit 133.

[0019] The control unit 113 includes a timer for measuring an energization time for the electric wires 15 and 16, and a memory for storing information such as a disconnection characteristic of the disconnection unit 111. The control unit 113 determines connection and disconnection of the disconnection unit 111 based on the energization time measured by the timer, the detected value of the detection unit 112, and the disconnection characteristic of the disconnection unit 111 stored in the memory, and transmits a control signal to the disconnection unit 111. The control unit 113 can calculate a temperature (heat quantity) of the connected electric wires 15 and 16 based on information obtained by the detection unit 112.

[0020] The control unit 123 includes a timer for measuring an energization time for the electric wire 17B and a memory for storing information such as a disconnection characteristic of the disconnection unit 121. The control unit 123 determines connection and disconnection of the disconnection unit 121 based on the energization time measured by the timer, the detected value of the detection unit 122, and the disconnection characteristic of the disconnection unit 121 stored in the memory, and transmits a control signal to the disconnection unit 121. The control unit 123 can calculate a temperature (heat amount) of the connected electric wire 17B based on information obtained by the detection unit 122.

[0021] The control unit 133 includes a timer for measuring an energization time for the electric wire 17C and a memory for storing information such as a disconnection characteristic of the disconnection unit 131. The control unit 133 determines connection and disconnection of the disconnection unit 131 based on the energization time measured by the timer, the detected value of the detection unit 132, and the disconnection characteristic of the disconnection unit 131 stored in the memory, and transmits a control signal to the disconnection unit 131. The control unit 133 can calculate a temperature (heat quantity) of the connected electric wire 17C based on information obtained by the detection unit 132.

[0022] Fig. 2 is a graph showing a relationship between an energization time and a change in a heat amount of the electric wire 15 and the like. Fig. 3 is a logarithmic graph showing a relationship between an excitation current of the electric wires 15 and 17B and a cut-off time (time from start of power supply to disconnection) of the cut-off units 111 and 121. A vertical axis of the graph is a logarithmic scale.

[0023] As shown by a one-dot chain line and a two-dot chain line in the graph of Fig. 2, the shutdown characteristic of the shutdown unit 111 is defined by a curve line indicating a relationship between a heat amount of the electric wire 15 and a shutdown time of the shutdown unit 111. As shown by a solid line and a dashed line in the graph of Fig. 2, the shutdown characteristic of the shutdown unit 121 is defined by a curve line indicating a relationship between a heat amount of the electric wires 17B and 17B' and a shutdown time of the shutdown unit 121. Although not shown in the graph of Fig. 2, the shutdown characteristic of the shutdown unit 131 is defined by a curve line indicating a relationship between a heat amount of the electric wire 17C and a shutdown time of the shutdown unit 131.

[0024] The control unit 113 of the first power distribution device 11 reads, from the shutdown characteristic of the shutdown unit 111, a shutdown time (threshold) corresponding to a temperature (heat amount) of the electric wires 15 and 16 calculated based on detected values ​​of excitation currents detected by the detection unit 112, and, when a power supply time measured by the timer exceeds the threshold, determines a shutdown of the shutdown unit 111 and transmits a shutdown signal to the shutdown unit 111.The control unit 123 of the second power distribution device 12 reads, from the shutdown characteristic of the shutdown unit 121, a shutdown time (threshold) corresponding to a temperature (heat amount) of the electric wire 17B calculated based on a detected value of an excitation current detected by the detection unit 122, and, when an energization time measured by the timer exceeds the threshold, determines a shutdown of the shutdown unit 121 and transmits a shutdown signal to the shutdown unit 121.The control unit 133 of the third power distribution device 13 reads, from the shutdown characteristic of the shutdown unit 131, a shutdown time (threshold) corresponding to a temperature (heat amount) of the electric wire 17C calculated based on a detected value of an excitation current detected by the detection unit 132, and, when an energization time measured by the timer exceeds the threshold, determines a shutdown of the shutdown unit 131 and transmits a shutdown signal to the shutdown unit 131.

[0025] As in Fig. 1, the control unit 113 of the first power distribution device 11, the control unit 123 of the second power distribution device 12, and the control unit 133 of the third power distribution device 13 are communicatively connected. The control unit 123 of the second power distribution device 12 transmits a detected value of an open-circuit voltage of the shutdown unit 121, which is detected by the detection unit 122, to the control unit 113 of the first power distribution device 11. The control unit 133 of the third power distribution device 13 transmits a detected value of an open-circuit voltage of the shutdown unit 131, which is detected by the detection unit 132, to the control unit 113 of the first power distribution device 11.

[0026] The control unit 113 of the first power distribution device 11 compares the detected value of the open-circuit voltage of the shutdown unit 121 received from the control unit 123 of the second power distribution device 12 with a detected value of an open-circuit voltage of the shutdown unit 111 received from the detection unit 112. The control unit 113 of the first power distribution device 11 determines that the shutdown unit 111 is located upstream of the shutdown unit 121 when the open-circuit voltage of the shutdown unit 111 is higher than the open-circuit voltage of the shutdown unit 121.

[0027] The control unit 113 of the first power distribution device 11 compares the detected value of the open-circuit voltage of the shutdown unit 131 received from the control unit 133 of the third power distribution device 13 with the detected value of the open-circuit voltage of the shutdown unit 111 received from the detection unit 112. The control unit 113 of the first power distribution device 11 determines that the shutdown unit 111 is located upstream of the shutdown unit 131 when the open-circuit voltage of the shutdown unit 111 is higher than the open-circuit voltage of the shutdown unit 131.A method of determining an upstream and downstream relationship between the shutdown unit 111 and the shutdown units 121 and 131 is not limited to the method based on the open-circuit voltage, and may be replaced by other methods such as storing information indicating the upstream and downstream relationship in advance.

[0028] The control units 113, 123 and 133 are communicable with an on-board communication device 18, which is Fig. 1. The communication device 18 is communicatively connected to a data center DC via a wireless communication network, such as a mobile phone network. The control units 113, 123, and 133 can transmit, to the communication device 18, an acquisition request for information related to a change in the on-board loads 2A, 2B, and 2C (hereinafter, load change information). The communication device 18 can transmit, to the data center DC, the acquisition request for the load change information received from the control units 113, 123, and 133. The data center DC stores load change information related to the shutdown characteristics of the shutdown units 111, 121, and 131, and can transmit the load change information to the communication device 18 in response to the received acquisition request.The communication device 18 can transmit the load change information received from the data center DC to the control units 113, 123, 133.

[0029] The control units 113, 123, and 133 can communicate with a service terminal ST in a wired or wireless manner. The control units 113, 123, and 133 can transmit a request for the load change information to the service terminal ST. The service terminal ST stores load change information related to the shutdown characteristics of the shutdown units 111, 121, and 131 and can transmit the load change information to the control units 113, 123, and 133 in response to the received request.

[0030] Here, a case will be described where the on-board load 2B connected to the cut-off unit 121 of the second power distribution device 12 is changed to the on-board load 2B'. An example is assumed where a state where the on-board load 2B, which is a small lighting device illuminating with a relatively small current, is connected to the cut-off unit 121 through the electric wire 17B of a standard corresponding to the small current, is changed to a state where the on-board load 2B', which is a large lighting device illuminating with a relatively large current, is connected to the cut-off unit 121 through the electric wire 17B' of a standard corresponding to the large current.

[0031] In this assumed example, as shown by a solid line in the graph of Fig. 3, a relationship between an exciting current and a shutdown time of the shutdown unit 121 corresponding to the on-board load 2B before a change is initially set according to an exciting current which is a relatively small current (I2). As shown by a dashed line in the graph of Fig. 3, a relationship between an exciting current and a cut-off time of the cut-off unit 121 corresponding to the changed on-board load 2B' is set according to an exciting current which is a relatively large current (I2').

[0032] A smoke emission characteristic of the electric wire 15 shown in the graph of Fig. 2 is indicated by a dotted line (a relationship between a heat quantity and a time from a start of power supply to smoke emission (hereinafter referred to as smoke emission time)) is initially set. A curve line indicating a relationship between an exciting current and a shutdown time of the shutdown unit 111 before a change, which is indicated by a one-dot chain line in the graph of Fig. 3 is initially set to fall between a curve line indicating a relationship between an exciting current and a shutdown time of the shutdown unit 121 before a change, and a curve line indicating a relationship between an exciting current of the electric wire 15 and a time until smoke is emitted. Although not shown in the graph of Fig. As shown in Figure 3, the curve indicating the relationship between the exciting current and the off-time of the shutdown unit 111 before the change is initially set to fall between a curve indicating a relationship between an exciting current and a off-time of the shutdown unit 131 and a curve indicating the relationship between the exciting current of the electric wire 15 and the time until smoke is emitted. That is, the relationship between the exciting current and the off-time of the shutdown units 111, 121, and 131 is initially set such that the off-time of the shutdown unit 111 is shorter than the smoke emission time of the electric wire 15 and longer than the off-time of the shutdown units 121 and 131.

[0033] On the other hand, the curve line indicating the relationship between the exciting current and the turn-off time of the turn-off unit 111 before the change indicated by the one-dot chain line in the graph of Fig. 3, a curve line indicating a relationship between an exciting current and a cut-off time of the cut-off unit 121 after the change when the exciting current is I3 (>I2'>I2), and does not fall between the curve line indicating the relationship between the exciting current and the cut-off time of the cut-off unit 121 after the change and the curve line indicating the relationship between the exciting current of the electric wire 15 and the time until smoke is emitted. That is, when the excitation current is equal to or greater than I3, the shutdown time of the shutdown unit 111 is shorter than the shutdown time of the shutdown unit 121. Therefore, when the excitation current is I3, the shutdown unit 111 and the shutdown unit 121 are turned off at the same time, resulting in a situation where not only the on-board load 2B' but also the ECU 4 cannot be operated at the same time when an abnormality occurs in the on-board load 2B'.

[0034] Therefore, in the power distribution device 10 according to the present embodiment, when there is a change in the on-board loads 2B and 2C on the downstream side, not only the shutdown characteristics of the shutdown units 121 and 131 corresponding to the changed on-board loads 2B and 2C are changed, but also the shutdown characteristic of the shutdown unit 111 on the upstream side are changed. Specifically, first, the control units 113, 123, and 133 acquire detected values ​​of voltages and currents of the shutdown units 111, 121, and 131 from the detection units 112, 122, and 132 each time the power supply device 1 is reset. The control units 113, 123, and 133 determine whether a change process of the shutdown characteristics of the shutdown units 111, 121, and 131 is necessary according to an amount of change in the detected values ​​of the voltages and currents of the shutdown units 111, 121, and 131.In the above assumed example, since the detected values ​​of the voltages and currents of the shutdown unit 121 change when the on-board load 2B connected to the shutdown unit 121 is changed to the on-board load 2B', the control unit 123 determines that the change process of the shutdown characteristic of the shutdown unit 121 is necessary.

[0035] When the control units 113, 123, and 133 determine that the shutdown characteristics of the shutdown units 111, 121, and 131 need to be changed, the control units 113, 123, and 133 transmit a request for load change information to the data center DC or the service terminal ST and receive the load change information from the data center DC or the service terminal ST. The control units 113, 123, and 133 change the shutdown characteristics of the shutdown units 111, 121, and 131 according to the received load change information.

[0036] Next, the control unit 113 of the first power distribution device 11 changes the shutdown characteristic of the shutdown unit 111 so that the curve indicating the relationship between the exciting current and the shutdown time of the shutdown unit 111 falls between the curve indicating the relationship between the exciting current and the shutdown time of the shutdown units 121 and 131 after the change and the curve indicating the relationship between the exciting current of the electric wire 15 and the time until smoke is emitted. A process of changing the shutdown characteristic of the shutdown unit 111 on the upstream side after changing or adding the onboard loads 2B and 3B on the downstream side will be described below.

[0037] Fig. 4 is a flowchart showing a process for changing the shutdown characteristic of the shutdown unit 111 on the upstream side after the onboard loads 2B and 2C on the downstream side are changed or added. The process shown in this flowchart is started when the power supply device 1 is reset.

[0038] First, the control units 113, 123, and 133 obtain detected values ​​of voltages and currents of the shutdown units 111, 121, and 131 from the detection units 112, 122, and 132, and determine whether a change amount of the detected value from a previous reset of the power supply device 1 exceeds a threshold (step S1). If the determination in step S1 is YES, the process proceeds to step S2, and if the determination in step S1 is NO, the process proceeds to a normal process.

[0039] Next, the control units 113, 123, and 133 transmit a load change information acquisition request to the data center DC or the service terminal ST and acquire the load change information, such as the shutdown characteristics for the on-board load after the change (step S2). Next, the control units 113, 123, and 133 change the shutdown characteristics of the corresponding shutdown units 111, 121, and 131 based on the acquired load change information (step S3).

[0040] Next, the control unit 113 acquires detected values ​​of open-circuit voltages of the shutdown units 111, 121, and 131 detected by the detection units 112, 122, and 132, and determines upstream and downstream relationships of the shutdown units 111, 121, and 131 based on the acquired detected values ​​(step S4).

[0041] Next, the control unit 123 transmits a shutdown characteristic of the shutdown unit 121 to the control unit 113, and the control unit 133 transmits a shutdown characteristic of the shutdown unit 131 to the control unit 113 (step S5). Next, the control unit 113 calculates a heat quantity of the electric wires 15, 17B, 17B', and 17C (hereinafter referred to as the electric wire 15 or the like) when a virtual continuous current flows through the electric wires 15, 17B, 17B', and 17C using the following formulas (1) to (6) (step S6).

[0042] When energization of the electric wire 15 or the like is started, the control unit 113 calculates a heat generation amount X1 per unit length of the electric wire 15 or the like using the following formula (1). [Formula 1] X1=l2×Ron×Δt

[0043] Where I is a detected value of a current of the detection units 112, 122 and 132, R on electrical resistance per unit length of the electric wire 15 or the like, and Δt is a sampling time (for example, 5 msec.).

[0044] The control unit 113 calculates a heat release amount Y1 of the electric wire 15 or the like using the following formula (2). [Formula 2] Y1=Q / (Cth∗×Rth / Δt)

[0045] Where C th * is a pseudo heat capacity per unit length of the electric wire 15 or the like, R th is the thermal resistance per unit length of the electric wire 15 or the like, Δt is a sampling time (for example, 5 msec.), and Q is a heat quantity per unit length of the electric wire 15 or the like and is a value obtained by multiplying an electric wire temperature by the pseudo heat capacity C th* is received.

[0046] The control unit 113 calculates an electric wire temperature T n , using the following formula (3). [Formula 3] Tn=Tp+(X1−Y1) / Cth∗

[0047] Where T p a temperature of the electric wire 15 or the like at the time of a previous measurement.

[0048] That is, every time the sampling time Δt has passed, the control unit 113 calculates the electric wire temperature T n of the electric wire 15 or the like at a current measuring time by successively adding the heat generation amount X1 or subtracting the heat release amount Y1 to the temperature T p of the electric wire 15 or the like at the time of the previous measurement.

[0049] The following is a procedure for calculating the pseudo-heat capacity C th* As indicated by the curve line defined by the one-dot chain line in the graph of Fig. 2, when any current continuously flows through the electric wire 15 or the like, a heat amount of the electric wire 15 or the like increases. It should be understood that a temperature T2 of the electric wire 15 and the like at this time is expressed by the following formula (4). [Formula 4] T2=T1+l2×Ron×Rth{1−e(−t / Cth⋅Rth)}

[0050] T1 is an ambient temperature, C th is a heat capacity per unit length of the electric wire 15 or the like, and t is a elapsed time.

[0051] The control unit 113 calculates a temperature threshold ΔT max , which is expressed by the following formula (5), based on a continuous excitable current I maxfrom a fuse with a standard normally used for electrical wire 15 or the like. The continuous excitable current I max of the fuse can be obtained by actually passing a current through the fuse and measuring a current and a time until the fuse blows. [Formula 5] ΔTmax=Rth×Ron×lmax2

[0052] The temperature threshold ΔT max is an upper limit of a temperature rise ΔT with respect to the ambient temperature, and if the shutdown unit 111 is disconnected when the temperature rise ΔT, ΔT max exceeds, the disconnection unit 111 is disconnected with a characteristic equivalent to that of the fuse described above.

[0053] In the above formula (4), when T2-T1=ΔT, the following formula (4') is obtained. [Formula 6] ΔT=l2×Ron×Rth{1−e(−t / Cth⋅Rth)}

[0054] By appropriately changing the current I in the above formula (4'), increasing the elapsed time t for each current I, and plotting a time when the temperature rise ΔT exceeds the temperature threshold ΔT max reaches, a curve line is obtained showing the relationship between the excitation current and the turn-off time shown in the graph of Fig. 3. By multiplying the temperature threshold ΔT max with a mass and a specific heat of the electric wire 15 or the like, threshold values ​​of the heat quantity (cut-off threshold A, cut-off threshold A', cut-off threshold B and cut-off threshold B') shown in the graph of Fig. 2 are shown.

[0055] By setting a value of the temperature threshold ΔT max, which is calculated by the above formula (5), is substituted for ΔT in the above formula (4'), and modifying the formula so that a left side represents the heat capacity C th and further replacing the heat capacity C th with the pseudo-heat capacity C th *, the following formula (6) is obtained. [Formula 7] Cth∗=−tRthln(1−ΔTmaxRthRonl2)

[0056] As shown in the flowchart in Fig. 4, the control unit 113 calculates the shutdown time of each of the shutdown units 111, 121, and 131 when the virtual continuous current flows through the electric wire 15 or the like, based on the heat amount and the shutdown threshold of each of the shutdown units 111, 121, and 131 (step S7).

[0057] Next, the control unit 113 determines whether the shutdown time of the shutdown units 121 and 131 is longer than the shutdown time of the shutdown unit 111 (step S8). As shown in the graph of Fig. 2, in an initial setting, the shutdown time T1 of the shutdown unit 111 is longer than the shutdown time T2 of the shutdown unit 121, but after a change in the on-board load 2B, the shutdown time T1 of the shutdown unit 111 is expected to be shorter than a shutdown time T2' of the shutdown unit 121. As shown in the flowchart in Fig. 4, if the determination in step S8 is YES, the process proceeds to step S9, and if the determination in step S8 is NO, the process proceeds to a normal process.

[0058] The control unit 113 changes a time constant τ shown in the following formula (7) to change the shutdown characteristic of the shutdown unit 111 so that the shutdown characteristic of the shutdown unit 111 falls between the shutdown characteristics of the shutdown units 121 and 131 after the change and the smoke emission characteristic of the electric wire 15 (step S9). Consequently, as shown in the graph of Fig. 2, a shutdown time T1' of the shutdown unit 111 is longer than the shutdown time T2' of the shutdown unit 121. [Formula 8] τ=Cth⋅Rth=t2B,+twx ln(1−l15lsim)

[0059] T 2B' is a shutdown time of the shutdown unit 121 in a state where the on-board load 2B' is connected after the change through the electric wire 17B'. t w is a smoke emission time of the electric wire 15. I 15is an initially fixed value of an excitation current of the electric wire 15. I sim is the virtual continuous current. x is a real number in a range from 0 <x<∞. Wenn sich x 0 annähert, nähert sich die Abschalt-Charakteristik der Abschalteinheit 111 der geänderten Abschalt-Charakteristik der Abschalteinheit 121 an. Im Gegensatz dazu, wenn sich x ∞ annähert, nähert sich die Abschalt-Charakteristik der Abschalteinheit 111 der Rauchemissionscharakteristik des elektrischen Drahts 15 an.

[0060] The above formula (7) is obtained by converting the above formula (6) into the following formula (8) with ΔT max as a left side, and then converting the following formula (8) into a formula with the time constant τ as a left side, and then converting ΔT maxinto a value between a temperature threshold of the shutdown unit 121 after the change to the on-board load 2B' and a temperature threshold for the smoke emission characteristic of the electric wire 15. [Formula 9] ΔTmax=RthRonl2(1−e(−t / Cth⋅Rth))=RthRonl2(1−e−t / τ)

[0061] As shown in the flowchart in Fig. As shown in Figure 4, the control unit 113 determines whether the shutdown time of the shutdown unit 111 is longer than the shutdown time of the shutdown units 121 and 131 (step S10). If the determination in step S10 is YES, the process proceeds to a normal process, and if the determination in step S10 is NO, an alarm process is executed (step S11), and the process proceeds to the normal process.

[0062] As described above, in the power distribution device 10 according to the present embodiment, when the on-board loads 2B and 2C connected to the second power distribution device 12 and the third power distribution device 13 on the downstream side are changed or added, the shutdown characteristics of the shutdown units 121 and 131 of the second power distribution device 12 and the third power distribution device 13 are changed. In this situation, when the shutdown time of the shutdown unit 111 of the first power distribution device 11 on the upstream side is shorter than the shutdown time of the shutdown units 121 and 131, the control unit 113 of the first power distribution device 11 on the upstream side changes the shutdown characteristic of the shutdown unit 111 such that the shutdown time of the shutdown unit 111 is longer than the shutdown time of the shutdown units 121 and 131.Consequently, when the on-board loads 2B and 2C connected to the second power distribution device 12 and the third power distribution device 13 on the downstream side are added or changed, the electric wire 15 and the like can be protected from the upstream side to the downstream side without requiring redesign of the breaker units 111, 121, and 131. It is also possible to prevent simultaneous shutdown between the breaker unit 111 on the upstream side and the breaker units 121 and 131 on the downstream side.

[0063] In the power distribution device 10 according to the present embodiment, the shutdown characteristics of the upstream-side shutdown unit 111 and the downstream-side shutdown units 121 and 131 are initially set such that the shutdown time of the shutdown unit 111 and the shutdown units 121 and 131 is shorter than the smoke emission time, which is a time from a start of power supply to the smoke emission of the electric wire 15. The shutdown characteristics of the shutdown unit 111 and the shutdown units 121 and 131 are initially set such that the shutdown time of the shutdown unit 111 is longer than the shutdown time of the shutdown units 121 and 131.In contrast, in a situation where the on-board loads 2B and 2C connected to the second power distribution device 12 and the third power distribution device 13 on the downstream side are changed or added, and the shutdown characteristics of the shutdown units 121 and 131 are changed, if the shutdown time of the shutdown unit 111 is shorter than the shutdown time of the shutdown units 121 and 131, the control unit 113 changes the shutdown characteristic of the shutdown unit 111 such that the shutdown time of the shutdown unit 111 is longer than the shutdown time of the shutdown units 121 and 131 and shorter than the smoke emission time of the electric wire 15. Consequently, it is possible to simultaneously shut down the shutdown unit 111 on the upstream side and the shutdown units 121 and 131 on the downstream side, and reliably prevent the electric wire 15 from smoking.

[0064] In the power distribution device 10 according to the present embodiment, the upstream-side control unit 113 and the downstream-side control units 123 and 133 are communicatively connected to each other. The upstream-side control unit 113 receives the shutdown characteristics of the downstream-side shutdown units 121 and 131 from the downstream-side control units 123 and 133. The upstream-side control unit 113 calculates the shutdown time of the shutdown units 121 and 131 when a predetermined excitation current flows through the electric wires 17B, 17B', and 17C based on the received shutdown characteristics of the shutdown units 121 and 131.The upstream control unit 113 calculates, based on the shutdown characteristic of the shutdown unit 111, the shutdown time of the shutdown unit 111 when a predetermined excitation current flows through the electric wires 15 and 16. If the calculated shutdown time of the shutdown unit 111 is shorter than the calculated shutdown time of the shutdown units 121 and 131, the upstream control unit 113 changes the shutdown characteristic of the shutdown unit 111 such that the shutdown time of the shutdown unit 111 is longer than the shutdown time of the shutdown units 121 and 131. Consequently, it is possible to compare the shutdown time of the shutdown units 111, 121 and 131 after changing or adding the on-board loads 2B and 2C, and to change the shutdown characteristic of the shutdown unit 111 based on a comparison result.

[0065] In the power distribution device 10 according to the present embodiment, the first power distribution device 11 on the upstream side includes the detection unit 112 that detects the voltage and current of the shutdown unit 111, and the second power distribution device 12 and the third power distribution device 13 on the downstream side include the detection units 122 and 132 that detect the voltage and current of the shutdown units 121 and 131. The control unit 113 of the first power distribution device 11 receives detected values ​​of voltages and currents of the shutdown units 121 and 131, detected by the detection units 122 and 132, from the control units 123 and 133 of the second power distribution device 12 and the third power distribution device 13.Consequently, the control unit 113 of the first power distribution device 11 can determine the upstream and downstream relationships of the shutdown units 111, 121, and 131 by comparing the voltage of the shutdown unit 111 on the upstream side and the voltages of the shutdown units 121 and 131 on the downstream side. The control unit 113 of the first power distribution device 11 can calculate a heat quantity of the electric wire 15 or the like based on the currents of the shutdown units 111, 121, and 131.

[0066] The present disclosure has been described above based on the above-described embodiment, but the present disclosure is not limited to the above-described embodiment, and modifications may be made to the above-described embodiment, and publicly known or well-known techniques may be appropriately combined within a scope not deviating from the spirit of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-014 748 A [0002, 0003, 0004] JP 2022- 000 363 A [0002, 0003, 0004]

Claims

[1] Energy distribution device (10), comprising: a first power distribution device (11) configured to distribute power supplied from a power supply device (1); and a second power distribution device (12) configured to distribute power distributed by the first power distribution device (11) to an on-board device (2A, 2B, 2B', 2C, 3A, 3C, 4), wherein the first energy distribution device (11) comprises: a first disconnection unit (111) configured to connect or disconnect a first electrical wire (14, 15) supplying power from the power supply device (1) to the second power distribution device (12); and a first control unit (113) configured to control the first disconnection unit (111) based on a first disconnection characteristic indicating a relationship between a heat quantity of the first electric wire (14, 15) and a first disconnection time, which is a time from a start of the power supply to the first electric wire (14, 15) to the disconnection of the first disconnection unit (111), the second energy distribution device (12) comprises: a second disconnection unit (121) configured to connect or disconnect a second electrical wire (15, 17B) supplying power from the first power distribution device (11) to the on-board device; and a second control unit (123) configured to control the second disconnection unit (121) based on a second disconnection characteristic indicating a relationship between a heat quantity of the second electric wire (15, 17B) and a second disconnection time, which is a time from a start of the power supply to the second electric wire (15, 17B) to the disconnection of the second disconnection unit (121), wherein the first shutdown characteristic and the second shutdown characteristic are initially set such that the first shutdown time is longer than the second shutdown time, and the first control unit (113) executes a first shutdown characteristic changing process of changing the first shutdown characteristic such that the first shutdown time is longer than the second shutdown time when the on-board device is changed or added and the second shutdown characteristic is changed and the first shutdown time is shorter than the second shutdown time. [2] Energy distribution device (10) according to claim 1, wherein the first cut-off characteristic and the second cut-off characteristic are initially set such that the first cut-off time and the second cut-off time are shorter than a smoke emission time, which is a time from the start of the power supply to the smoke emission of the first electric wire (14, 15), and the first control unit (113) changes the first shutdown characteristic in the first shutdown characteristic changing process such that the first shutdown time is longer than the second shutdown time and shorter than the smoke emission time. [3] Energy distribution device (10) according to claim 1 or 2, wherein the first control unit (113) and the second control unit (123) are communicatively connected, and the first control unit (113) is configured to: Receiving the second shutdown characteristic from the second control unit (123); Calculating the first turn-off time when a predetermined excitation current flows through the first electric wire (14, 15) based on the first turn-off characteristic; Calculating the second turn-off time when the predetermined excitation current flows through the second electric wire (15, 17B) based on the second turn-off characteristic; and Executing the first shutdown characteristic change process when the calculated first shutdown time is shorter than the calculated second shutdown time. [4] Energy distribution device (10) according to claim 3, wherein the first power distribution device (11) has a first detection unit (112) configured to detect a voltage and a current of the first shutdown unit (111), the second power distribution device (12) has a second detection unit (112) configured to detect a voltage and a current of the second shutdown unit (121), and the first control unit (113) receives a detected value of the voltage and current of the second shutdown unit (121), which is detected by the second detection unit (122), from the second control unit (123).

Images