WO2024024088A1 - Auxiliary power supply device - Google Patents

Abstract

In the present invention, by controlling the charging operation of a charging unit provided in a second conduction path that branches from a first conduction path, the current that flows from a power path into the first conduction path is kept to an upper limit current value or less.　This auxiliary power supply (60) comprises: a first conduction path (61) over which current supplied from a power path (30) flows; a second conduction path (62) and a third conduction path (63) that branch from the first conduction path (61); a charging unit (64) that performs at least the charging operation of supplying a charging current to a power storage unit (40) on the basis of power supplied from the second conduction path (62); and a control unit (65) that controls the charging unit (64). The control unit (65) causes the charging unit (64) to perform the charging operation so as to keep the current that flows into the first conduction path (61) from the power path (30) to the upper limit current value or less.

Description

Auxiliary power supply

The present disclosure relates to an auxiliary power supply device.

In a configuration where there are multiple wires (branch sections) branching from one wire (main section) and power is supplied to the load from each branch section, a current that is a superimposition of the current flowing through each branch section flows through the main section. become. In such a configuration, heat generation in the main body increases depending on the number of loads and the current value required by the loads, and it is necessary to increase the diameter of the electric wire in the main body in order to suppress overheating.

Therefore, it is conceivable to apply a configuration like the power supply control device disclosed in Patent Document 1. The power supply control device of Patent Document 1 is connected to a power source and is configured to supply power to a plurality of loads through a plurality of electric wires, respectively. Each of the wires has a predetermined upper limit of allowable temperature. The control unit of the power supply control device protects the electric wire by stopping power supply to the load when the temperature of the electric wire is equal to or higher than the upper limit temperature.

Japanese Patent Application Publication No. 2016-12972

For example, a configuration can be considered in which charging current is supplied to the power storage element via a branch part, and current is supplied to the load via another branch part. However, when the configuration of the power supply control device of Patent Document 1 is applied to each branch part with such a configuration, the charging time of the power storage element becomes longer by cutting off the charging current to the power storage element. It is difficult to apply the cutoff configuration to loads where it is not desired to cut off the current supply. Therefore, there is a need for a configuration that can control the current flowing through the main body without interrupting the current flowing through the branch portion.

The present disclosure discloses that by controlling the charging operation of the charging unit provided in the second conductive path branching from the first conductive path, the current flowing from the power path to the first conductive path can be suppressed to below the upper limit current value. purpose.

An auxiliary power supply device according to the present disclosure includes:
An auxiliary power supply device used in a power supply system including a power supply unit, a power path that is a route through which power is supplied from the power supply unit, and a power storage unit,
a first conductive path that is electrically connected to the power path and through which a current supplied from the power path flows;
a second conductive path and a third conductive path branching from the first conductive path;
a charging unit that is provided between the second conductive path and the power storage unit and performs at least a charging operation to supply charging current to the power storage unit based on the power supplied from the second conductive path;
a control unit that controls the charging unit;
has
The control unit causes the charging unit to perform the charging operation so as to suppress a current flowing from the power path into the first conductive path to a maximum current value or less.

The technology according to the present disclosure suppresses the current flowing into the first conductive path from the power path to below the upper limit current value by controlling the charging operation of the charging unit provided in the second conductive path branching from the first conductive path. Can be done.

FIG. 1 is a block diagram schematically illustrating a power supply system including an auxiliary power supply device according to a first embodiment. FIG. 2 is an explanatory diagram illustrating a state in which current flows from the power supply unit to the power storage unit and the load in the block diagram of FIG. 1. FIG. 3 is an explanatory diagram illustrating changes in each current value with respect to elapsed time in the auxiliary power supply device of the first embodiment. FIG. 4 is an explanatory diagram illustrating changes in each current value with respect to elapsed time in the auxiliary power supply device of the second embodiment. FIG. 5 is a block diagram schematically illustrating a power supply system including the auxiliary power supply device of the third embodiment. FIG. 6 is an explanatory diagram illustrating the cutoff characteristics of the fuse in the power supply system of the fourth embodiment.

Below, embodiments of the present disclosure are listed and illustrated. Note that the features [1] to [8] exemplified below may be combined in any manner as long as there is no contradiction.

[1] An auxiliary power supply device used in a power supply system including a power supply unit, a power path that is a path through which power is supplied from the power supply unit, and a power storage unit,
a first conductive path that is electrically connected to the power path and through which a current supplied from the power path flows;
a second conductive path and a third conductive path branching from the first conductive path;
a charging unit that is provided between the second conductive path and the power storage unit and performs at least a charging operation to supply charging current to the power storage unit based on the power supplied from the second conductive path;
a control unit that controls the charging unit;
has
The control unit causes the charging unit to perform the charging operation so as to suppress the current flowing from the power path into the first conductive path to an upper limit current value or less. The auxiliary power supply device.

The auxiliary power supply device in [1] above controls the current flowing from the power path into the first conductive path to an upper limit current value by controlling the charging operation of the charging section provided in the second conductive path branching from the first conductive path. It can be kept below. Therefore, the current flowing into the first conductive path can be suppressed below the upper limit current value without controlling the current in the third conductive path branching from the first conductive path.

[2] The auxiliary power supply device described in [1] has the following features. The auxiliary power supply device includes a current sensor that detects the current value of the first conductive path. The control unit controls the charging operation of the charging unit based on the detection result of the current sensor so that the current flowing from the power path to the first conductive path is equal to or less than the upper limit current value.

In the above auxiliary power supply device [2], the current value of the first conductive path can be directly grasped by the current sensor, and the current flowing into the first conductive path can be set to the upper limit current value by controlling the charging operation of the charging section. It becomes easier to increase the accuracy of keeping the value below.

[3] The auxiliary power supply device described in [1] has the following features. The auxiliary power supply device includes a second current sensor that detects a current value of the second conductive path, and one or more third current sensors that are arranged to be able to detect a current flowing from the first conductive path to the third conductive path. and has. The control unit controls the charging unit to control a current flowing from the power path to the first conductive path to be equal to or less than the upper limit current value, based on the detection result of the second current sensor and the detection result of the third current sensor. The above-mentioned charging operation is controlled.

In the auxiliary power supply device of [3] above, the current flowing in the first conductive path is indirectly grasped using the second current sensor provided in the second conductive path and the third current sensor provided in the third conductive path. can do.

[4] The auxiliary power supply device according to any one of [1] to [3] has the following features. The control unit adjusts the current value of the second conductive path to the above on condition that the sum of a predetermined target current value smaller than the upper limit current value and the current value of the third conductive path is equal to or less than the upper limit current value. When performing the first control to approach the target current value and causing the charging unit to perform the charging operation in a state where the sum of the target current value and the current value of the third conductive path exceeds the upper limit current value, A second control is performed to limit the current value of the second conductive path to a value lower than the target current value while suppressing the current flowing into the first conductive path to below the upper limit current value.

In the above auxiliary power supply device [4], in a state where the sum of the predetermined target current value smaller than the upper limit current value and the current value of the third conductive path is equal to or less than the upper limit current value, the first conductive path is connected to the upper limit current value. It is permitted to flow a current of the target current value so as not to exceed the target current value. Therefore, when the conditions for such a state are met, by performing the first control (control that brings the current value of the second conductive path closer to the target current value), the second conductive path is supplied with the desired target current value. Can conduct current. When the sum of the target current value and the current value of the third conductive path exceeds the upper limit current value, it is necessary to reduce the current value of the first conductive path so as not to exceed the upper limit current value. Therefore, by performing second control (control that limits the current value of the second conductive path to a value lower than the target current value and suppresses the current flowing into the first conductive path to below the upper limit current value), the first conductive path The current can be suppressed below the upper limit current value.

[5] The auxiliary power supply device according to any one of [1] to [4] has the following features. When the sum of a predetermined target current value smaller than the upper limit current value and the current value of the third conductive path is smaller than the upper limit current value, the control unit changes the current value of the first conductive path to the upper limit current value. Control is performed to increase the target current value so that it approaches the target current value.

In the above auxiliary power supply device [5], when the sum of the predetermined target current value that is smaller than the upper limit current value and the current value of the third conductive path is smaller than the upper limit current value, the current value of the first conductive path is the upper limit. There is room to increase the target current value within a range that does not exceed the current value. Therefore, in such a case, by performing control to increase the target current value so that the current value of the second conductive path approaches the target current value, the current value of the first conductive path can be kept below the upper limit current value. Charging current can be increased.

[6] The auxiliary power supply device according to any one of [1] to [5] has the following features. The power supply system includes a cutoff section that cuts off energization of the first conductive path when a current value of the power path reaches a cutoff current value. The upper limit current value is less than the breaking current value.

In the above auxiliary power supply device [6], since the upper limit current value is less than the cutoff current value, it is possible to prevent the cutoff part from being cut off by suppressing the current flowing into the first conductive path below the upper limit current value. .

[7] The auxiliary power supply device according to any one of [1] to [5] has the following features. The control unit changes the upper limit current value based on the current value of the first conductive path.

In the auxiliary power supply device of [7] above, by changing the upper limit current value, it becomes easier to appropriately change the state of the current in the first conductive path depending on the load connected to the third conductive path.

[8] The auxiliary power supply device described in [7] has the following features. In the power supply system, a fuse is provided in the power path. The above-mentioned fuse is based on the cut-off characteristic that determines the allowable time for each current value, and when a current of any value flows for more than the allowable time corresponding to the above-mentioned value in the above-mentioned cut-off characteristic, the above-mentioned first conductive conductor It operates to cut off the electricity to the road. The control unit is configured to control, in the interrupting characteristic, the permissible time corresponding to the elapsed time while a predetermined elapsed time has elapsed since the current value of the first conductive path became a current value equal to or higher than a predetermined lower limit current value. The upper limit current value is made smaller than the corresponding current value.

In the above auxiliary power supply device [8], based on the cutoff characteristics of the fuse, when the current value of the first conductive path reaches one of the current values, how long (allowable time) will the current flow at that current value? This makes it possible to determine whether the energization of the first conductive path is interrupted. Therefore, when the current value of the first conductive path becomes a current value equal to or higher than a predetermined lower limit current value that causes the interruption characteristic, the permissible time corresponding to the elapsed time is By making the upper limit current value smaller than the corresponding current value, it is possible to prevent the fuse from interrupting the energization of the first conductive path.

<First embodiment>
[Power system configuration]
The power supply system 10 shown in FIG. 1 includes a power supply section 20, a power path 30, a power storage section 40, loads 51 and 52, and an auxiliary power supply device 60. The power supply system 10 is mounted on, for example, a vehicle. The power supply system 10 is used as a power supply for operating loads 51 and 52 mounted on a vehicle.

The power supply unit 20 functions as a main power supply that continuously supplies power to the loads 51 and 52. The power supply unit 20 is a DC power supply that generates a DC voltage. The power supply section 20 is configured by a battery such as a lead battery, for example. A high potential side terminal of the power supply unit 20 is electrically connected to the power path 30, and a low potential side terminal of the power supply unit 20 is electrically connected to ground. The power supply section 20 applies a predetermined voltage to the power path 30. The power path 30 is a path to which power is supplied from the power supply section. Note that in this specification, a voltage is a voltage with respect to ground unless otherwise specified.

In the present disclosure, "to be electrically connected" desirably refers to a configuration in which they are connected in a mutually conductive state (a state in which current can flow) so that the potentials of both objects to be connected are equalized. However, the configuration is not limited to this. For example, "to be electrically connected" may refer to a configuration in which both connection objects are connected in a state where they can be electrically conductive, with an electrical component interposed between the two connection objects.

A fuse 32 is provided in the power path 30. The fuse 32 corresponds to the "blocking section" of the present disclosure. The fuse 32 cuts off the energization of the first conductive path 61 when the current value of the power path 30 reaches a cutoff current value. The breaking current value is, for example, a fixed value.

The loads 51 and 52 are, for example, in-vehicle electrical equipment. The loads 51 and 52 may be actuators such as motors, for example. Alternatively, the loads 51 and 52 may be an ECU or actuator in an electric parking brake system, an ECU or actuator in a shift-by-wire control system, or the like. Alternatively, it may be an in-vehicle electrical device other than these.

The power storage unit 40 functions as an auxiliary power source for the loads 51 and 52. Power storage unit 40 is a DC power supply that outputs DC voltage, and is, for example, an electric double layer capacitor. Power storage unit 40 is charged and discharged via charging unit 64, which will be described later.

The auxiliary power supply device 60 supplies power supplied from the power supply section 20 to the power storage section 40 and the loads 51 and 52. The auxiliary power supply device 60 includes a first conductive path 61 , a second conductive path 62 , a third conductive path 63 , a charging section 64 , a control section 65 , and a current sensor 66 .

A current supplied from the power path 30 flows through the first conductive path 61. One end of the first conductive path 61 is electrically connected to the power path 30. The other end of the first conductive path 61 is electrically connected to the second conductive path 62 and the third conductive path 63.

The second conductive path 62 and the third conductive path 63 are branched from the first conductive path 61. One end of the second conductive path 62 is electrically connected to the other end of the first conductive path 61 . The other end of the second conductive path 62 is electrically connected to the charging section 64.

The third conductive path 63 includes a power source side conductive path 63A and load side conductive paths 63B and 63C. The load side conductive paths 63B and 63C are branched from the power source side conductive path 63A. One end of the power source side conductive path 63A is electrically connected to the other end of the first conductive path 61. The other end of the power source side conductive path 63A is electrically connected to one end of the load side conductive path 63B and one end of the load side conductive path 63C.

The other end of the load-side conductive path 63B is electrically connected to the load 51. A switch element 63D is provided on the load side conductive path 63B. The switch element 63D is composed of a relay switch or a semiconductor switch such as a MOSFET. The switch element 63D is switched by the control unit 65 between an on state in which the load-side conductive path 63B is allowed to be energized and an off state in which the energization is cut off.

The other end of the load-side conductive path 63C is electrically connected to the load 52. A switch element 63E is provided on the load side conductive path 63C. The switch element 63E is composed of a relay switch or a semiconductor switch such as a MOSFET. The switch element 63E is switched by the control unit 65 between an on state in which the load-side conductive path 63C is allowed to be energized and an off state in which the energization is cut off.

The charging unit 64 is provided between the second conductive path 62 and the power storage unit 40. Charging unit 64 performs charging and discharging operations for power storage unit 40 . Charging unit 64 performs a charging operation of supplying charging current to power storage unit 40 based on the power supplied from second conductive path 62 . Charging section 64 operates under the control of control section 65, which will be described later. The charging unit 64 is configured as, for example, a DCDC converter. The charging unit 64 performs constant current operation and constant voltage operation. In constant current operation, the charging current is output as a target charging current (also referred to as a target current value) through feedback control. In constant voltage operation, the output voltage is output at the target charging voltage by feedback control. In constant voltage operation, the charging current is not necessarily constant. As a discharging operation, charging section 64 performs a voltage conversion operation of increasing or decreasing the voltage output from power storage section 40 and applying it to second conductive path 62 .

The control unit 65 controls the operation of supplying power from the power supply unit 20 to the power storage unit 40 and the loads 51 and 52. The control unit 65 is an information processing device having an information processing function, an arithmetic function, a control function, and the like. The control unit 65 is mainly composed of, for example, a microcomputer, and includes an arithmetic unit such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an A/D converter, etc. have. The control section 65 has a function of controlling the charging section 64 and the switch elements 63D and 63E.

The current sensor 66 detects the current value of the first conductive path 61. The current value detected by the current sensor 66 is a value (specifically, an analog voltage value) that can specify the current value of the first conductive path 61. The current sensor 66 is configured, for example, as a current detection circuit. The first conductive path 61 is electrically connected to the power path 30 and has the same potential as the power path 30 . Accordingly, current sensor 66 may detect current in power path 30 .

[Auxiliary power supply operation]
When supplying power from the power supply section 20 to the power storage section 40 and the loads 51, 52, the auxiliary power supply device 60 turns on the switch elements 63D, 63E as shown in FIG. A current flows through 63. The current value of the current flowing into the first conductive path 61 from the power supply section 20 is assumed to be Iin. The current flowing from the first conductive path 61 to the second conductive path 62 is assumed to be I2. The current flowing from the first conductive path 61 to the third conductive path 63 is assumed to be I3. The current of the first conductive path 61 is a superimposed current of the second conductive path 62 and the third conductive path 63. That is, Iin is the sum of I2 and I3.

Based on the detection result of the current sensor 66, the control unit 65 causes the charging unit 64 to perform a charging operation so as to suppress the current flowing from the power path 30 into the first conductive path 61 to below the upper limit current value. Specifically, the control unit 65 performs first control and second control described below. The control unit 65 performs first control to bring the current value of the second conductive path 62 closer to the target current value on the condition that the sum of the target current value and the current value of the third conductive path 63 is less than or equal to the upper limit current value. conduct. The target current value is a target current value of the current supplied to power storage unit 40 (current flowing through first conductive path 61). The target current value is smaller than the upper limit current value. When the sum of the target current value and the current value I3 of the third conductive path 63 is less than or equal to the upper limit current value, for example, the current value I2 of the second conductive path 62 is Charging operation is performed to reach the target current value.

In a state where the sum of the target current value smaller than the upper limit current value and the current value I3 of the third conductive path is less than the upper limit current value, the current of the target current value is controlled so that the first conductive path 61 does not exceed the upper limit current value. It is allowed to flow. Therefore, when the conditions for such a state are satisfied, by performing the first control (control for bringing the current value I2 of the second conductive path 62 closer to the target current value), the second conductive path 62 is set to the desired target value. Current can be passed at the current value.

When the control unit 65 causes the charging unit 64 to perform a charging operation in a state where the sum of the target current value and the current value I3 of the third conductive path 63 exceeds the upper limit current value, the control unit 65 controls the current value I2 of the second conductive path 62. A second control is performed to suppress the current Iin flowing into the first conductive path 61 to below the upper limit current value while limiting the current Iin to a value lower than the target current value. For example, if the sum of the target current value and the current value I3 of the third conductive path 63 exceeds the upper limit current value, for example, as in the time T2 to T3 shown in FIG. 3, I2 is set lower than the target current value. While limiting, Iin is kept below the upper limit current value. Thereby, the current Iin flowing into the first conductive path 61 can be suppressed below the upper limit current value without controlling the current value I3 of the third conductive path 63.

Since the upper limit current value is less than the cutoff current value of the fuse 32, by suppressing the current flowing into the first conductive path 61 below the upper limit current value, it is possible to prevent the fuse 32 from being cut off. By suppressing the current flowing into the first conductive path 61 below the upper limit current value without controlling the current in the third conductive path 63, there is no need to cut off the current flow to the third conductive path 63, and the third conductive path 63 It is possible to continue the operation of the loads 51 and 52 by continuing the power supply.

The following description relates to an example of the effect of this configuration.
The auxiliary power supply device 60 controls the current flowing into the first conductive path 61 from the power path 30 to an upper limit current value by controlling the charging operation of the charging unit 64 provided in the second conductive path 62 branching from the first conductive path 61. It can be kept below. Therefore, the current flowing into the first conductive path 61 can be suppressed below the upper limit current value without controlling the current in the third conductive path 63 branching from the first conductive path 61.

Furthermore, the auxiliary power supply device 60 includes a current sensor 66 that detects the current value of the first conductive path 61. As a result, the current value of the first conductive path 61 can be directly grasped by the current sensor 66, and the accuracy of suppressing the current flowing into the first conductive path 61 below the upper limit current value is increased by controlling the charging operation of the charging section. It becomes easier to increase.

In a state where the sum of a predetermined target current value smaller than the upper limit current value and the current value of the third conductive path is less than the upper limit current value, the current of the target current value is controlled so that the first conductive path does not exceed the upper limit current value. It is allowed to flow. Therefore, when the conditions for such a state are satisfied, the auxiliary power supply device 60 performs the first control (control that brings the current value of the second conductive path closer to the target current value) to increase the current value of the second conductive path. Current can be caused to flow at a desired target current value. When the sum of the target current value and the current value of the third conductive path exceeds the upper limit current value, it is necessary to reduce the current value of the first conductive path so as not to exceed the upper limit current value. Therefore, the auxiliary power supply device 60 performs second control (control that limits the current flowing into the first conductive path to below the upper limit current value while limiting the current value of the second conductive path to a value lower than the target current value). Accordingly, the current in the first conductive path can be suppressed to below the upper limit current value.

Further, since the upper limit current value of the auxiliary power supply device 60 is less than the cutoff current value, it is possible to prevent the fuse 32 from being cut off by suppressing the current flowing into the first conductive path 61 below the upper limit current value.

<Second embodiment>
The power supply system 10 of the second embodiment differs from the first embodiment in the operation of the auxiliary power supply device 60, but is common in other respects. Note that the same components as in the first embodiment are given the same reference numerals, and detailed explanations will be omitted.

Similar to the first embodiment, the auxiliary power supply device 60 turns on switch elements 63D and 63E as shown in FIG. 2 when supplying power from the power supply section 20 to the power storage section 40 and the loads 51 and 52. , current flows through each conductive path 61, 62, 63.

Based on the detection result of the current sensor 66, the control unit 65 causes the charging unit 64 to perform a charging operation so as to suppress the current flowing from the power path 30 into the first conductive path 61 to below the upper limit current value. Specifically, the control unit 65 sets the current value Iin of the first conductive path 61 when the sum of the target current value smaller than the upper limit current value and the current value I3 of the third conductive path 63 is smaller than the upper limit current value. Control is performed to increase the target current value so that it approaches the upper limit current value. When the sum of the target current value and the current value I3 of the third conductive path 63 is smaller than the upper limit current value, for example, as in the time T21 to T22 shown in FIG. 4, the current value Iin of the first conductive path 61 The target current value is increased so that the current value approaches the upper limit current value.

In a state where the sum of the target current value and the current value of the third conductive path 63 is smaller than the upper limit current value, there is room to increase the target current value within a range where the current value of the first conductive path 61 does not exceed the upper limit current value. . Therefore, in such a case, by performing control to increase the target current value so that the current value of the second conductive path 62 approaches the target current value, the current value of the first conductive path 61 can be made below the upper limit current value. It is possible to increase the charging current while suppressing the charging current.

<Third embodiment>
The power supply system 210 of the third embodiment includes a second current sensor 266A, a third current sensor 266B, 266C, and a second conductive path 62 and a third conductive path 63 (specifically, load-side conductive paths 63B, 63C), respectively. ) is different from the first embodiment in that the current is detected, but is the same in other respects. Note that the same components as in the first embodiment are given the same reference numerals, and detailed explanations will be omitted.

As shown in FIG. 5, the auxiliary power supply device 260 includes a second current sensor 266A and third current sensors 266B and 266C. The second current sensor 266A and the third current sensors 266B and 266C are configured, for example, as a current detection circuit. The second current sensor 266A detects the current value of the second conductive path 62. The current value detected by the second current sensor 266A is a value (specifically, an analog voltage value) that can specify the current value of the second conductive path 62. The third current sensors 266B and 266C are arranged in the third conductive path 63 so as to be able to detect the current flowing from the first conductive path 61 to the third conductive path 63. The third current sensor 266B detects the current value of the load-side conductive path 63B of the third conductive path 63. The current value detected by the third current sensor 266B is a value (specifically, an analog voltage value) that can specify the current value of the load-side conductive path 63B. The third current sensor 266C detects the current value of the load side conductive path 63C of the third conductive path 63. The current value detected by the third current sensor 266C is a value (specifically, an analog voltage value) that can specify the current value of the load-side conductive path 63C.

Add the current in the second conductive path 62 detected by the second current sensor 266A and the current in the third conductive path 63 (load-side conductive paths 63B, 63C) detected by the third current sensors 266B, 266C. The current thus generated becomes the current of the first conductive path 61. Therefore, the current flowing through the first conductive path 61 can be indirectly grasped using the second current sensor 266A and the third current sensors 266B and 266C.

The auxiliary power supply device 260 performs the same control as in the first embodiment or the same control as in the second embodiment based on the detection results of the second current sensor 266A and the third current sensors 266B and 266C. That is, the auxiliary power supply device 260 causes the charging unit 64 to perform a charging operation so as to suppress the current flowing from the power path 30 into the first conductive path 61 to below the upper limit current value. This produces the same effects as the first embodiment or the second embodiment.

<Fourth embodiment>
The power supply system of the fourth embodiment differs from the first embodiment in the method of setting the upper limit current value, but is the same in other respects. Note that the same components as in the first embodiment are given the same reference numerals, and detailed explanations will be omitted.

The control unit 65 changes the upper limit current value based on the current value Iin of the first conductive path 61. By changing the upper limit current value, it becomes easier to appropriately change the state of the current in the first conductive path 61 depending on the loads 51, 52, etc. connected to the third conductive path 63.

The fuse 32 disconnects the first conductive path 61 when a current of any value flows for longer than the allowable time associated with any of the values in the interrupting characteristic, based on the interrupting characteristic that determines the allowable time for each current value. It operates to cut off the power supply. The cutoff characteristic determines how much current value continues to flow for how long when the path (power path 30) is cut off. For example, as shown in FIG. 6, the larger the current value flowing through the fuse 32 is, the shorter the allowable time is set.

The control unit 65 controls the current value Iin of the first conductive path 61 to correspond to a permissible time corresponding to the elapsed time in the cutoff characteristic while a predetermined elapsed time has elapsed since the current value Iin of the first conductive path 61 became a current value equal to or higher than a predetermined lower limit current value. Control is performed to make the upper limit current value smaller than the current value. The lower limit current value is, for example, the lower limit current value of the current value associated with the allowable time in the interrupting characteristic. The lower limit current value is, for example, a reference value larger than the rated current of the fuse 32. For example, the control unit 65 includes a timer (not shown), and measures the time elapsed since the current value Iin of the first conductive path 61 reaches a predetermined lower limit current value. Assuming that the elapsed time is t1, it can be seen from the interruption characteristics shown in FIG. 6 that the current value (also referred to as fusing current value) corresponding to the allowable time t1 is Ia. Therefore, the upper limit current value is set to the current value Ib smaller than the fusing current value Ia while the elapsed time t1 elapses after the current value Iin of the first conductive path 61 becomes a current value equal to or higher than the lower limit current value. Thereby, it is possible to prevent the fuse 32 from cutting off the electricity to the first conductive path 61 .

<Other embodiments>
The present disclosure is not limited to the embodiments described above and illustrated in the drawings. For example, the features of the embodiments described above or below can be combined in any combination without contradicting each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. Furthermore, the embodiment described above may be modified as follows.

In the first to fourth embodiments described above, a configuration in which two loads 51 and 52 are provided in the power supply system 10 is illustrated, but a configuration in which one or three or more loads are provided may be used. Specifically, although a configuration in which the third conductive path 63 branches into two and is connected to the loads 51 and 52 is illustrated, a configuration in which the third conductive path 63 does not branch and is connected to one load is also possible. , the third conductive path 63 may be branched into three or more branches, and a load may be connected to each branch. By providing a current sensor on each of the branched conductive paths, the sum of the current values detected by the respective current sensors can be understood as the current flowing through the third conductive path 63.

In the third embodiment, the third current sensors 266B and 266C are provided in the load side conductive paths 63B and 63C, respectively, but instead of these current sensors, a current sensor is provided in the power source side conductive path 63A. There may be. Even with such a configuration, the value of the current flowing through the third conductive path 63 can be detected, and the value of the current flowing through the first conductive path 61 can be determined together with the value of the current flowing through the second conductive path 62.

In the first embodiment, the control unit 65 sets the current value of the second conductive path 62 to the target current value on the condition that the sum of the target current value and the current value of the third conductive path 63 is equal to or less than the upper limit current value. Control (first control) was performed to bring the value closer to the value. However, instead of such control, the control unit 65 controls the current value Iin of the first conductive path 61 when the sum of the target current value and the current value I3 of the third conductive path 63 is smaller than the upper limit current value. Control may be performed to increase the target current value so that it approaches the upper limit current value.

It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the range equivalent to the claims. be done.

10...Power supply system 20...Power supply section 30...Power line 32...Fuse (cutoff section)
40... Power storage units 51, 52...Load 60...Auxiliary power supply device 61...First conductive path 62...Second conductive path 63...Third conductive path 63A...Power source side conductive path 63B, 63C...Load side conductive path 63D, 63E ...Switch element 64...Charging unit 65...Control unit 66...Current sensor 210...Power system 260...Auxiliary power supply device 266A...Second current sensor 266B, 266C...Third current sensor

Claims (8)

1. An auxiliary power supply device used in a power supply system including a power supply unit, a power path that is a route through which power is supplied from the power supply unit, and a power storage unit,
   a first conductive path that is electrically connected to the power path and through which a current supplied from the power path flows;
   a second conductive path and a third conductive path branching from the first conductive path;
   a charging unit that is provided between the second conductive path and the power storage unit and performs at least a charging operation to supply charging current to the power storage unit based on the power supplied from the second conductive path;
   a control unit that controls the charging unit;
   has
   The control unit causes the charging unit to perform the charging operation so as to suppress the current flowing from the power path into the first conductive path to an upper limit current value or less. The auxiliary power supply device.
2. comprising a current sensor that detects a current value of the first conductive path,
   The control unit controls the charging operation of the charging unit so that the current flowing from the power path to the first conductive path is equal to or less than the upper limit current value based on the detection result of the current sensor. Auxiliary power supply as described.
3. a second current sensor that detects a current value of the second conductive path;
   one or more third current sensors arranged to be able to detect a current flowing from the first conductive path to the third conductive path;
   has
   The control unit controls the charging unit to control the current flowing from the power path to the first conductive path to be equal to or less than the upper limit current value based on the detection result of the second current sensor and the detection result of the third current sensor. The auxiliary power supply device according to claim 1 , wherein the auxiliary power supply device controls the charging operation of the battery.
4. The control unit adjusts the current value of the second conductive path to the current value on the condition that the sum of a predetermined target current value smaller than the upper limit current value and the current value of the third conductive path is equal to or less than the upper limit current value. When performing the first control to approach the target current value and causing the charging unit to perform the charging operation in a state where the sum of the target current value and the current value of the third conductive path exceeds the upper limit current value, the first control Any one of claims 1 to 3, wherein second control is performed to limit the current value of the second conductive path to a value lower than the target current value while suppressing the current flowing into the first conductive path to below the upper limit current value. Auxiliary power supply device according to paragraph 1.
5. The control unit sets the current value of the first conductive path to the upper limit current when a sum of a predetermined target current value smaller than the upper limit current value and a current value of the third conductive path is smaller than the upper limit current value. The auxiliary power supply device according to claim 1 or 2, wherein control is performed to increase the target current value so as to approach the target current value.
6. The power supply system includes a cutoff unit that cuts off energization of the first conductive path when the current value of the power path reaches a cutoff current value,
   The auxiliary power supply device according to claim 1 or 2, wherein the upper limit current value is less than the cutoff current value.
7. The auxiliary power supply device according to claim 1 or 2, wherein the control unit changes the upper limit current value based on the current value of the first conductive path.
8. The power supply system is one in which a fuse is provided in the power path,
   Based on a cutoff characteristic that defines a permissible time for each current value, the fuse disables the first conductive current when a current of any value flows for longer than a permissible time corresponding to any value in the cutoff characteristic. operates to cut off electricity to the road,
   The control unit is configured to adjust the cutoff characteristic to the allowable time corresponding to the elapsed time while a predetermined elapsed time elapses after the current value of the first conductive path becomes a current value equal to or higher than a predetermined lower limit current value. The auxiliary power supply device according to claim 7, wherein the upper limit current value is smaller than a corresponding current value.

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