JP7294155B2 - Control device - Google Patents

Description

The present invention relates to a control device for a power supply system that includes a first storage battery and a second storage battery.

2. Description of the Related Art Conventionally, as a device for determining abnormality of a current sensor that detects charging/discharging current of a storage battery, a device for estimating an operating current flowing through an electric load connected to the storage battery is known (for example, Patent Document 1). In this device, if the difference between the current value detected by the current sensor and the estimated operating current value is greater than or equal to a predetermined value, it is determined that the current sensor is abnormal.

Japanese Patent No. 6437100

Abnormalities in a power supply system including a storage battery include, in addition to current sensor abnormalities, overcurrent abnormalities in which overcurrent flows in electrical paths, and these abnormalities must be distinguished and determined. In the conventional device, if the current value detected by the current sensor is larger than a predetermined threshold value, it is determined that there is an overcurrent abnormality. For example, in a power supply system including a first storage battery and a second storage battery connected in parallel to a power generation device having a power generation function, the power generation device and the first storage battery are connected, and the power generation device and the second storage battery are connected. When using the first storage battery that has been cut off, it is determined whether or not there is an overcurrent abnormality in the electrical path on the side of the first storage battery. When it is determined that there is an overcurrent abnormality due to a ground fault or the like, if the storage battery used is switched from the first storage battery to the second storage battery, the influence of the ground fault or the like also affects the second storage battery. Therefore, when it is determined that there is an overcurrent abnormality on the first storage battery side, the second storage battery is protected by maintaining the disconnection state between the power generation device and the second storage battery, and the first storage battery is protected. A measure was taken to protect the first storage battery by blowing a fuse provided in the electrical path on the side.

The abnormality of the current sensor includes a fixed upper limit abnormality in which the current value detected by the current sensor is fixed at the upper limit of the detection range of the current sensor. Therefore, when a fixed upper limit anomaly occurs as an anomaly of the current sensor, it is impossible to distinguish between an overcurrent anomaly and an anomaly of the current sensor based on the current value detected by the current sensor. For example, when an abnormality occurs in the first current sensor that detects the charge/discharge current of the first storage battery, it is erroneously determined that there is an overcurrent abnormality on the side of the first storage battery, and the connection between the power generator and the second storage battery is cut off. If this state is maintained, there is concern that the second storage battery will be in an over-discharged state.

The present invention has been made in view of the above circumstances, and an object of the present invention is to discriminate between an overcurrent abnormality and a current sensor abnormality in a power supply system including a first storage battery and a second storage battery. It is an object of the present invention to provide a control device capable of taking measures to cope with an abnormality.

A first means for solving the above problems includes a first storage battery and a second storage battery connected in parallel to a power generation device having a power generation function, and the power generation device, the first storage battery, and the second storage battery. A first switch and a first fuse are provided in a first electrical path on the first storage battery side of a connection point between the power generation device and the first storage battery and the second storage battery, A second switch and a second fuse are provided in a second electrical path closer to the second storage battery than the connection point, and a first current sensor for detecting current flowing in the first electrical path and the second electrical path. and a second current sensor that detects the current flowing through the power supply system, and in a first state in which one of the first switch and the second switch is closed and the other switch is open a first determination unit for determining whether or not the detected current detected by the current sensor on the one switch side is greater than a first threshold; When it is determined that the current sensor has increased, the current sensor on the one switch side detects it at a predetermined timing after a predetermined period of time from the determination until the fuse on the one switch side melts. a second determination unit that determines whether or not the detected current is greater than a second threshold; and if the second determination unit determines that the detected current is greater than the second threshold, the first switch and switching the state of the second switch to a second state in which the one switch is open and the other switch is closed, and the second determination unit determines that the detected current is smaller than the second threshold. a state control unit that maintains the states of the first switch and the second switch in the first state when the determination is made.

In a power supply system that includes a first storage battery and a second storage battery that are connected in parallel to a power generation device, for example, a first switch provided in a first electrical path on the first storage battery side is closed, and a switch on the second storage battery side is closed. When the first storage battery is used with the second switch provided on the second electrical path opened, it is determined whether or not the first electrical path on the side of the first storage battery has an overcurrent abnormality.

When it is determined that the detected current, which is the current flowing through the first electric path and detected by the first current sensor, is greater than the first threshold value, it is determined that there is an overcurrent abnormality on the first storage battery side or the first current It is conceivable that an upper limit fixing error has occurred in the sensor. In other words, when the upper limit fixing abnormality occurs as the abnormality of the first current sensor, the overcurrent abnormality on the first storage battery side and the abnormality of the first current sensor are distinguished based on the detected current detected by the first current sensor. I can't judge. When an abnormality occurs in the first current sensor, it is erroneously determined that there is an overcurrent abnormality in the first storage battery, and when the second switch is maintained in an open state, the connection between the power generation device and the second storage battery is established. is maintained in an interrupted state, the second storage battery is in an over-discharged state.

In this regard, in the above configuration, when it is determined that the detected current detected by one of the current sensors is greater than the first threshold value, it is determined whether or not the fuse corresponding to this current sensor is blown. I made it Specifically, whether or not the detected current exceeds the second threshold at a predetermined timing after a predetermined period required for the fuse to melt after it is determined that the detected current has exceeded the first threshold. determined whether or not When an abnormality occurs in one of the current sensors, the detected current at a predetermined timing becomes larger than the second threshold. Further, when an overcurrent abnormality occurs in one of the storage batteries, the corresponding fuse blows and the detected current at a predetermined timing becomes smaller than the second threshold. Therefore, an overcurrent abnormality and an abnormality of the current sensor can be discriminated and determined, and appropriate measures corresponding to each abnormality can be implemented.

When it is determined that one of the current sensors is abnormal, by switching the states of the first switch and the second switch, it is possible to control the other storage battery using the other current sensor in which no abnormality has occurred, For example, it is possible to prevent the other storage battery from being overdischarged. Further, when it is determined that one of the storage batteries has an overcurrent abnormality, maintaining the states of the first switch and the second switch prevents the other storage battery from being affected by the overcurrent abnormality. can be suppressed.

In a second means, the power supply system is applied to a vehicle equipped with an engine and supplies power to a starter that imparts rotational force to the engine when the engine is started, and the connection point is a first connection point. wherein, in the first electric path, the first switch is provided between the first connection point and the first storage battery, and the starter is provided between the first switch and the first storage battery. is connected to a second connection point, and the state control unit determines that the one switch is the second switch when the second determination unit determines that the detected current is greater than the second threshold Under the condition that the states of the first switch and the second switch are switched to the second state.

If the power supply system supplies power to the starter of the vehicle, this starter may be connected to the first storage battery. In this case, the states of the first switch and the second switch are switched based on the determination that the first current sensor is abnormal, and when the first switch is opened, the power generation device charges the first storage battery. is stopped. As a result, when the remaining capacity of the first storage battery becomes less than the capacity required to operate the starter, the starter cannot be operated using the first storage battery. In the above configuration, when it is determined that the first current sensor is abnormal, the states of the first switch and the second switch are not switched, and the first switch is maintained in the closed state. Therefore, even if the first current sensor becomes abnormal, the starter can be preferably operated.

The whole block diagram of a power supply system. FIG. 4 is a diagram showing blowing characteristics of a fuse; 4 is a flowchart showing the procedure of control processing; 5 is a time chart showing control processing when an overcurrent abnormality occurs on the second storage battery side; 5 is a time chart showing control processing when an abnormality occurs in the second current sensor; 4 is a time chart showing control processing when an abnormality occurs in the first current sensor; FIG. 10 is a view for explaining measures to be taken when an overcurrent abnormality occurs on the second storage battery side; FIG. 5 is a diagram for explaining measures to be taken when an abnormality occurs in the second current sensor; FIG. 5 is a diagram for explaining measures to be taken when an abnormality occurs in the first current sensor; FIG. 10 is a diagram for explaining measures to be taken when an overcurrent abnormality occurs on the first storage battery side;

(First embodiment)
A first embodiment in which a control device according to the present invention is applied to a power supply system 100 mounted on a vehicle that runs using an engine as a drive source will be described below with reference to the drawings.

As shown in FIG. 1 , a power supply system 100 is a system that supplies electric power to a rotating electrical machine 10 , a starter motor (hereinafter referred to as starter) 16 , and a load 18 . The power supply system 100 includes a first storage battery 12 , a second storage battery 14 and a control device 40 .

The rotary electric machine 10 has functions of power running drive and regenerative drive, and is specifically an MG (Motor Generator) or an ISG (Integrated Starter Generator). The rotary electric machine 10 performs power input/output between the first storage battery 12 and the second storage battery 14 . The rotating shaft of the rotating electric machine 10 is drivingly connected to an engine output shaft (not shown) by a belt or the like. causes the engine output shaft to rotate. The rotary electric machine 10 is driven by electric power input from at least one of the first storage battery 12 and the second storage battery 14 during power running, and applies rotational force to the engine output shaft. During regenerative driving, the rotating electric machine 10 generates power by rotating the engine output shaft, and outputs power to at least one of the first storage battery 12 and the second storage battery 14 . In addition, in this embodiment, the rotary electric machine 10 corresponds to "a power generation device having a power generation function".

The first storage battery 12 and the second storage battery 14 are chargeable and dischargeable storage batteries, and are assembled batteries in which a plurality of battery cells are connected in series. The first storage battery 12 is, for example, a lead storage battery, which is a well-known general-purpose storage battery. On the other hand, the second storage battery 14 is, for example, a lithium ion storage battery. Therefore, the second storage battery 14 is a high-density storage battery with less power loss during charging and discharging and higher output density and energy density than the first storage battery 12 .

The first storage battery 12 and the second storage battery 14 are connected in parallel with the rotating electric machine 10 . Hereinafter, in the electric path connecting the rotating electrical machine 10 and the first storage battery 12 and the second storage battery 14, the first storage battery side of the first connection point P1 between the rotating electrical machine 10 and the first storage battery 12 and the second storage battery 14 is referred to as a first electrical path L1, and the electrical path closer to the second storage battery than the first connection point P1 is referred to as a second electrical path L2.

A first switch SW1 and a first fuse 26 are provided in the first electrical path L1. The first switch SW1 includes a first switching element 21 and a second switching element 22 connected in series, and a first current sensor 24 is connected between the first and second switching elements 21 and 22. configured as follows.

In this embodiment, N-channel MOSFETs (hereinafter simply MOSFETs) are used as the first and second switching elements 21 and 22 . Therefore, a parasitic diode 23 is connected in parallel to the first and second switching elements 21 and 22 . The first and second switching elements 21 and 22 are connected in series so that the anodes of the parasitic diodes 23 are connected to each other.

The first current sensor 24 detects a first current IA flowing through the first electrical path L1. The first fuse 26 is a fuse having predetermined fusing characteristics. As shown in FIG. 2, the fuse blows when a current greater than the current threshold Ith flows over a predetermined blowing period TB. The fusing characteristic means these current threshold value Ith and fusing period TB. In this embodiment, the blowing period TB corresponds to "a predetermined period required until the fuse blows".

In the first electrical path L1, the first switch SW1 is connected between the first connection point P1 and the first storage battery 12, and the first fuse 26 connects the first switch SW1 and the first storage battery 12. connected between That is, the first switch SW1 and the first fuse 26 are connected in series in the first electrical path L1.

The starter 16 is connected to the second connection point P2 between the first fuse 26 and the first storage battery 12 . The starter 16 has its rotary shaft drivingly connected to the engine output shaft, and provides initial torque to the engine by power supply from the first storage battery 12 when the engine is started.

Also, the load 18 is connected to a third connection point P3 between the first switch SW1 and the first fuse 26. As shown in FIG. That is, load 18 is connected to first storage battery 12 via first fuse 26 . The load 18 is, for example, a power steering device that controls steering of the vehicle, a room lamp, and a body control ECU that controls an air conditioner, doors, and the like.

A second switch SW2 and a second fuse 36 are provided on the second electrical path L2. The second switch SW2 includes a third switching element 31 and a fourth switching element 32 connected in series, and a second current sensor 34 is connected between the third and fourth switching elements 31 and 32. configured as follows.

In this embodiment, MOSFETs are used as the third and fourth switching elements 31 and 32 . Therefore, a parasitic diode 33 is connected in parallel to the third and fourth switching elements 31 and 32 . The third and fourth switching elements 31 and 32 are connected in series so that the anodes of the parasitic diodes 33 are connected to each other.

The second current sensor 34 detects a second current IB flowing through the second electrical path L2. First and second currents IA and IB detected by first and second current sensors 24 and 34 are input to control device 40 .

In the second electrical path L2, the second switch SW2 is connected between the first connection point P1 and the second storage battery 14, and the second fuse 36 is connected between the second storage battery 14 and ground. ing. That is, the second switch SW2 and the second fuse 36 are connected in series via the second storage battery 14 .

The control device 40 generates a control signal SD and outputs the control signal SD to each switching element 21 , 22 , 31 , 32 to control each switching element 21 , 22 , 31 , 32 . The open/closed states of the first and second switches SW1 and SW2 are switched by the control signal SD. Specifically, by controlling the first and second switching elements 21 and 22 to be in an open state, the first switch SW1 is switched to an open state, and the first and second switching elements 21 and 22 are to a closed state. By being controlled, the first switch SW1 is switched to the closed state. The same applies to the second switch SW2.

Also, the control device 40 is connected to an IG switch 41 and a notification unit 42 and controls them. The IG switch 41 is a vehicle activation switch. The notification unit 42 is a device that notifies the driver visually or audibly, and is, for example, a display or speaker installed in the vehicle compartment.

The control device 40 has a well-known microcomputer comprising a CPU, ROM, RAM, flash memory, and the like. The CPU refers to the arithmetic programs and control data in the ROM, and implements various functions for controlling the vehicle. For example, the control device 40 determines an overcurrent abnormality in the first electrical path L1 on the side of the first storage battery 12 based on the first current IA, and determines the second electrical path on the side of the second storage battery 14 based on the second current IB. Determine an overcurrent anomaly for L2.

The determination of the overcurrent abnormality on the first storage battery 12 side is performed when the first storage battery 12 is used with the first switch SW1 closed and the second switch SW2 open. In this determination, it is determined whether or not the first current IA detected by the first current sensor 24 has become larger than the current threshold value Ith. However, when it is determined that the first current IA is greater than the current threshold value Ith, it is conceivable that there is an overcurrent abnormality on the side of the first storage battery 12 or that an upper limit fixation abnormality has occurred in the first current sensor 24. . Here, the fixed upper limit abnormality of the first current sensor 24 refers to the first current detected by the first current sensor 24 even though the current flowing through the first electrical path L1 is within the detection range of the first current sensor 24. An abnormality in which the current IA is fixed at the upper limit of the detection range of the first current sensor 24 .

That is, when the upper limit fixing abnormality occurs as the abnormality of the first current sensor 24, based on the first current IA detected by the first current sensor 24, the overcurrent abnormality on the first storage battery 12 side and the first current sensor 24 It cannot be determined by distinguishing it from the abnormality of When an abnormality occurs in the first current sensor 24, it is erroneously determined that there is an overcurrent abnormality in the first storage battery 12, and the second switch SW2 is kept open. Since the connection with the storage battery 14 is maintained in a disconnected state, the second storage battery 14 is in an over-discharged state.

In this embodiment, when it is determined that the currents IA, IB detected by one of the current sensors 24, 34 are greater than the current threshold value Ith, the fuses 26, 36 corresponding to the current sensors 24, 34 are is fused or not. Specifically, the currents IA, IB are set at a predetermined timing after the blowing period TB required for blowing the fuses 26, 36 has passed after it is determined that the currents IA, IB have become larger than the current threshold value Ith. has become larger than the current threshold value Ith. In this embodiment, the first current IA and the second current IB correspond to "detected current", and the current threshold Ith corresponds to "first threshold and second threshold".

FIG. 3 shows a flowchart of the control processing of this embodiment. The control device 40 repeatedly performs the control process at predetermined control cycles during the engine driving period in which the IG switch 41 is switched to the closed state.

When the control process is started, first, in step S10, it is determined whether or not the first storage battery 12 is being used. If the second storage battery 14 is used with the first switch SW1 open and the second switch SW2 closed, a negative determination is made in step S10. In this case, in step S11, it is determined whether or not the provisional determination flag F2 for determining an overcurrent abnormality on the second storage battery 14 side is turned on.

If a negative determination is made in step S11, it is determined in step S12 whether or not the second current IB has become larger than the current threshold value Ith.

If the second current sensor 34 does not have a fixed upper limit abnormality and the second storage battery 14 side does not have an overcurrent abnormality, the second current IB becomes smaller than the current threshold value Ith, and NO is determined in step S12. judge. In this case, the control process ends.

On the other hand, when the upper limit fixing abnormality occurs in the second current sensor 34, or when the overcurrent abnormality occurs on the side of the second storage battery 14, the second current IB becomes larger than the current threshold Ith, and an affirmative determination is made in step S12. . In this case, in step S13, the provisional determination flag F2 is switched to the ON state, and the control process ends.

On the other hand, if an affirmative determination is made in step S11, it is determined in step S14 whether or not a predetermined determination period TC (see FIG. 4) has elapsed since it was determined that the second current IB is greater than the current threshold value Ith.

Here, "after it is determined that the second current IB is greater than the current threshold value Ith" refers to the execution of the control process in which the provisional determination flag F2 is switched to the ON state in the control process that is repeatedly performed in each control cycle. From the timing, it means. Further, the determination period TC is set to a period longer than the fusing period TB. Note that, in the present embodiment, the timing at which the determination period TC has elapsed after it is determined that the second current IB is greater than the current threshold value Ith corresponds to the “predetermined timing”.

If a negative determination is made in step S14, the control process ends. On the other hand, if an affirmative determination is made in step S14, it is determined in step S16 whether or not the second current IB has become larger than the current threshold value Ith as re-determination of the second current IB.

When the second current sensor 34 has a fixed upper limit abnormality, the second current IB is kept larger than the current threshold value Ith, and an affirmative determination is made in step S16. In this case, in step S17, the provisional determination flag F2 is turned off. In subsequent step S18, the states of the first and second switches SW1 and SW2 are switched. That is, the first switch SW1 is switched to the closed state, and the second switch SW2 is switched to the open state. In subsequent step S20, the driver is notified of the abnormality of the second current sensor 34 using the notification unit 42, and the control process ends.

On the other hand, when an overcurrent abnormality occurs on the second storage battery 14 side due to a ground fault or the like, the second fuse 36 is blown and the second current IB becomes smaller than the current threshold value Ith, and a negative determination is made in step S16. In this case, in step S22, the states of the first and second switches SW1 and SW2 are maintained. That is, the first switch SW1 is kept open and the second switch SW2 is kept closed.

In subsequent step S24, the driver is notified of the overcurrent abnormality by using the notification unit 42, and the control process ends. In the notification of step S24, there is no usable storage battery as in the notification of step S20, and the power source of power supply system 100 is lost. Therefore, in the notification in step S24, the notification time and the notification intensity (for example, volume) are increased compared to the notification in step S20.

On the other hand, when the first storage battery 12 is in use with the first switch SW1 closed and the second switch SW2 open, an affirmative determination is made in step S10. In this case, in step S31, it is determined whether or not the provisional determination flag F1 for determining an overcurrent abnormality on the first storage battery 12 side is turned on. Hereinafter, for distinction, the provisional determination flag F1 for provisionally determining the overcurrent abnormality on the first storage battery 12 side will be referred to as the first provisional determination flag F1, and the temporary determination flag for provisionally determining the overcurrent abnormality on the second storage battery 14 side. The flag F2 is called a second provisional determination flag F2. In addition, in this embodiment, the processing of steps S12 and S32 corresponds to the "first determination unit".

If a negative determination is made in step S31, it is determined in step S32 whether or not the first current IA has become larger than the current threshold value Ith.

If the first current sensor 24 does not have a fixed upper limit abnormality and the first storage battery 12 side does not have an overcurrent abnormality, the first current IA becomes smaller than the current threshold value Ith, and NO is determined in step S32. judge. In this case, the control process ends.

On the other hand, when the upper limit fixing abnormality occurs in the first current sensor 24, or when the overcurrent abnormality occurs on the side of the first storage battery 12, the first current IA becomes larger than the current threshold Ith, and an affirmative determination is made in step S32. . In this case, in step S33, the first temporary determination flag F1 is switched to the ON state, and the control process ends.

On the other hand, if an affirmative determination is made in step S31, it is determined in step S34 whether or not a determination period TC has elapsed since it was determined that the first current IA is greater than the current threshold value Ith.

If a negative determination is made in step S34, the control process ends. On the other hand, if an affirmative determination is made in step S34, in step S36, as re-determination of the first current IA, it is determined again whether or not the first current IA has become larger than the current threshold value Ith. It should be noted that in the present embodiment, the processing of steps S16 and S36 corresponds to the "second determination section".

When the upper limit fixing abnormality occurs in the first current sensor 24, the state where the first current IA is larger than the current threshold value Ith is maintained, and an affirmative determination is made in step S36. In this case, in step S37, the first temporary determination flag F1 is turned off. In subsequent step S38, the states of the first and second switches SW1 and SW2 are maintained. That is, although the first current sensor 24 is abnormal, the first storage battery 12 is usable, so the first switch SW1 is kept closed and the second switch SW2 is kept open. Therefore, in the present embodiment, when it is determined in steps S16 and S36 that the current is greater than the current threshold Ith, the current determined to be greater than the current threshold Ith is the second current IB. , the states of the first and second switches SW1 and SW2 are switched. In subsequent step S40, the driver is notified of the abnormality of the first current sensor 24 by using the notification unit 42, and the control process ends.

On the other hand, when an overcurrent abnormality occurs on the first storage battery 12 side due to a ground fault or the like, the first fuse 26 is blown and the first current IA becomes smaller than the current threshold value Ith, and a negative determination is made in step S36. In this case, in step S42, the states of the first and second switches SW1 and SW2 are maintained. That is, the first switch SW1 is kept closed and the second switch SW2 is kept open. In subsequent step S44, the driver is notified of the overcurrent abnormality by using the notification unit 42, and the control process ends. Incidentally, in the present embodiment, the processes of steps S18, S22, S38, and S42 correspond to the "state control unit".

4 to 6 show an example of control processing. FIG. 4 shows changes in the second current IB when an overcurrent abnormality occurs on the second storage battery 14 side, and FIG. 5 shows changes in the second current IB when an abnormality occurs in the second current sensor 34. 6 shows transition of the first current IA when an abnormality occurs in the first current sensor 24. As shown in FIG.

4 and 5, (A) shows the transition of the second current IB, (B) shows the transition of the second temporary determination flag F2, and (C) shows the determination of abnormality of the second current sensor 34. It shows the transition of the abnormality determination flag F4 indicating the result. Further, in FIG. 6, (A) shows transition of the first current IA, (B) shows transition of the first provisional determination flag F1, and (C) shows determination of abnormality of the first current sensor 24. It shows the transition of the abnormality determination flag F3 indicating the result. In FIGS. 4-6 (B) and (C), the state determined to be abnormal is indicated by "on", and the state not determined to be abnormal is indicated by "off". Further, in FIGS. 4 to 6, (D) shows the transition of the state of the first switch SW1, and (E) shows the transition of the state of the second switch SW2.

As shown in FIG. 4, when the second current IB becomes greater than the current threshold Ith at time t1, it is provisionally determined that there is an overcurrent abnormality on the second storage battery 14 side, and the second provisional determination flag F2 is switched to the ON state.

In the control process shown in FIG. 4, the second fuse 36 is blown at time t2 when the blowing period TB has passed from time t1, and the second current IB becomes smaller than the current threshold Ith. Therefore, at time t3 when the determination period TC has passed from time t1, the second current IB becomes smaller than the current threshold Ith. In the present embodiment, the second current IB at time t3 is compared with the current threshold Ith, and if the second current IB is smaller than the current threshold Ith, the overcurrent abnormality on the second storage battery 14 side is officially determined. be. In this final determination, the second provisional determination flag F2 is kept on, and the abnormality determination flag F4 is kept off.

In this case, the first switch SW1 is kept open and the second switch SW2 is kept closed. That is, the used storage battery is maintained in the second storage battery 14 . As a result, as indicated by the dashed line in FIG. 7 , by switching the storage battery to be used to the first storage battery 12 , it is possible to suppress the first storage battery 12 from being affected by a ground fault or the like. The second switch SW2 is kept closed while the engine is running, and is switched to an open state when the engine is stopped.

Further, as shown in FIG. 5, when an abnormality occurs in the second current sensor 34, the current actually flowing through the second electrical path L2 is smaller than the current threshold value Ith, so the second fuse 36 is not blown. On the other hand, since the second current sensor 34 is abnormal, the second current IB at time t3 becomes greater than the current threshold Ith. In the present embodiment, if the second current IB is greater than the current threshold Ith at time t3, it is determined that the second current sensor 34 is abnormal. As a result, the second provisional determination flag F2 is switched off, and the abnormality determination flag F4 is switched on.

In this case, the first switch SW1 is switched to the closed state, and the second switch SW2 is switched to the open state. That is, the storage battery to be used is switched to the first storage battery 12 . As a result, the first storage battery 12 can be controlled using the first current sensor 24 in which no abnormality has occurred, as indicated by the dashed line in FIG.

Similarly, as shown in FIG. 6, when an abnormality occurs in the first current sensor 24, the current actually flowing through the first electrical path L1 is smaller than the current threshold Ith, so the first fuse 26 is not blown. . On the other hand, since the first current sensor 24 is abnormal, the first current IA at time t3 becomes greater than the current threshold Ith. In the present embodiment, when the first current IA is greater than the current threshold Ith at time t3, it is determined that the first current sensor 24 is abnormal. As a result, the first provisional determination flag F1 is switched off, and the abnormality determination flag F3 is switched on.

In this case, the first switch SW1 is kept closed and the second switch SW2 is kept open. That is, the storage battery used cannot be switched to the second storage battery 14 . As a result, as indicated by the dashed line in FIG. 9, the electric power is stored in the first storage battery 12 by the power generation function of the rotating electric machine 10, and the starter 16 and the load 18 are driven by the electric power stored in the first storage battery 12. becomes possible.

It should be noted that the transition when the overcurrent abnormality occurs in the first storage battery 12 is substantially the same as the transition when the overcurrent abnormality occurs in the second storage battery 14, so description of the time chart is omitted. As shown in FIG. 10, when an overcurrent abnormality occurs on the first storage battery 12 side, the first fuse 26 is blown. When the connection between the ground fault portion and the first storage battery 12 is cut off by fusing the first fuse 26, the first storage battery 12 becomes usable. In this embodiment, the starter 16 is connected to the second connection point P2 between the first fuse 26 and the first storage battery 12 on the first electrical path L1. Therefore, when the first storage battery 12 becomes usable due to the melting of the first fuse 26, the electric power currently stored in the first storage battery 12 can be used to operate the starter 16.

According to this embodiment detailed above, the following effects can be obtained.

In the power supply system 100 of the present embodiment, the first storage battery 12 and the second storage battery 14 are connected in parallel to the rotating electric machine 10, and the electric paths L1 and L2 provided with the storage batteries 12 and 14 are supplied with current Sensors 24,34 and fuses 26,36 are provided. In this embodiment, when it is determined that the currents IA and IB detected by one of the current sensors 24 and 34 are greater than the current threshold value Ith, it is determined whether the corresponding fuses 26 and 36 are blown. was determined.

Specifically, at a predetermined timing after the fusing period TB required for fusing the fuses 26 and 36 from the above determination has passed, that is, at time t3 after the determination period TC has passed since the above determination, the currents IA and IB are equal to the current threshold. It is determined whether or not it has become larger than Ith. When an abnormality occurs in one of the current sensors 24, 34, the currents IA, IB at time t3 become larger than the current threshold value Ith. Further, when an overcurrent abnormality occurs in one of the storage batteries 12, 14, the corresponding fuses 26, 36 are fused, causing the currents IA, IB at time t3 to become smaller than the current threshold value Ith. Therefore, an overcurrent abnormality and an abnormality of the current sensors 24 and 34 can be distinguished and determined.

- In the present embodiment, since an overcurrent abnormality and an abnormality of the current sensors 24 and 34 can be distinguished and determined, appropriate measures corresponding to each abnormality can be implemented. Specifically, when it is determined that the second current sensor 34 is abnormal, by switching the states of the first switch SW1 and the second switch SW2, the first current sensor 24 that is not abnormal is used for the first current sensor. 1 storage battery 12 can be controlled. As a result, for example, it is possible to prevent the first storage battery 12 from being over-discharged while the vehicle is running, thereby preventing the vehicle from running. Further, when an overcurrent abnormality on the second storage battery 14 side is determined, by maintaining the states of the first switch SW1 and the second switch SW2, it is possible to It is possible to suppress the impact. In other words, the safety of the vehicle and the driver can be ensured by implementing these appropriate measures.

In addition, in the present embodiment, since an overcurrent abnormality and an abnormality of the current sensors 24 and 34 can be distinguished and determined, the content of each abnormality can be notified to the driver. Therefore, for example, when an overcurrent abnormality occurs and the power supply from both the first storage battery 12 and the second storage battery 14 is stopped, the driver can be prompted to perform appropriate processing to stop the vehicle. can.

In the present embodiment, when it is determined that the current sensors 24 and 34 are abnormal, when it is determined that the second current sensor 34 is abnormal, the states of the first switch SW1 and the second switch SW2 are switched, while the first current sensor 24, the states of the first switch SW1 and the second switch SW2 are maintained. Therefore, even if an abnormality occurs in the first current sensor 24, the power generation function of the rotating electric machine 10 maintains the state in which electric power is stored in the first storage battery 12, and power is supplied to the load 18 while the vehicle is running. It can be carried out. Thereby, the function of the load 18 can be maintained during running. In addition, since the state in which electric power is stored in the first storage battery 12 is maintained, power can be supplied to the starter 16 . Thereby, the starter 16 can be preferably operated based on the electric power of the first storage battery 12 .

- In this embodiment, the determination period TC is set to be longer than the blowing period TB, and the determination period TC is determined based on the blowing characteristics of the fuses 26 and 36 . Therefore, the abnormality of the corresponding current sensors 24, 34 can be properly determined, and erroneous determination of the overcurrent abnormality of the storage batteries 12, 14 and the abnormality of the current sensors 24, 34 can be suppressed.

(Other embodiments)
The present invention is not limited to the description of the above embodiments, and may be implemented as follows.

- The kind of a 1st storage battery and a 2nd storage battery is not restricted to the said embodiment. For example, both the first storage battery and the second storage battery may be lithium ion storage batteries, or both may be lead storage batteries.

- Although the said embodiment demonstrated the form which the current threshold value Ith of the 1st current sensor 24 and the current threshold value Ith of the 2nd current sensor 34 are equal, it is not restricted to this. For example, these current thresholds Ith may be set to different values depending on the rated currents of the corresponding storage batteries 12 and 14 . Further, in each of the current sensors 24 and 34, the current threshold value Ith as the first threshold value used at time t1 and the current threshold value Ith as the second threshold value used at time t3 are equal to each other. can't For example, in each of the current sensors 24 and 34, the current threshold Ith as the second threshold may be set to a larger value than the current threshold Ith as the first threshold.

- In the above-described embodiment, the determination period TC of the first current sensor 24 and the determination period TC of the second current sensor 34 are equal, but this is not the only option. For example, these judgment periods TC may be set to periods different from each other according to the blowing periods TB of the corresponding fuses 26 and 36 .

- The controller and method described in the present disclosure can be performed by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program; may be implemented. Alternatively, the controller and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the control apparatus and techniques described in this disclosure can be implemented by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may also be implemented by one or more dedicated computers configured. The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible recording medium.

DESCRIPTION OF SYMBOLS 10... Rotary electric machine 12... 1st storage battery 14... 2nd storage battery 24... 1st current sensor 26... 1st fuse 34... 2nd current sensor 36... 2nd fuse 100... Power supply system L1... First electric path, L2... Second electric path, SW1... First switch, SW2... Second switch.

Claims (2)

A first storage battery (12) and a second storage battery (14) connected in parallel to a power generation device (10) having a power generation function are provided, and the power generation device is connected to the first storage battery and the second storage battery. A first switch (SW1) and a first switch (SW1) are connected to a first electrical path (L1) closer to the first storage battery than a connection point (P1) between the power generation device and the first storage battery and the second storage battery. A fuse (26) is provided, a second switch (SW2) and a second fuse (36) are provided in a second electrical path (L2) closer to the second storage battery than the connection point, and the first electrical Applied to a power supply system (100) comprising a first current sensor (24) that detects current flowing through a path and a second current sensor (34) that detects current flowing through the second electrical path,
In a first state in which one of the first switch and the second switch is closed and the other switch is open, the detected current detected by the current sensor of the one switch is a first threshold. a first determination unit that determines whether or not it has become larger than
When the first determination unit determines that the detected current is greater than the first threshold value, after a predetermined period of time required from the determination until the fuse on the one switch side melts has passed a second determination unit that determines, at a predetermined timing, whether or not the current detected by the current sensor on the one switch side has become larger than a second threshold;
When the second determination unit determines that the detected current is larger than the second threshold, the states of the first switch and the second switch are set to the open state of the one switch and the other switch is opened. When the second state is switched to the closed state, and the second determination unit determines that the detected current is smaller than the second threshold value, the states of the first switch and the second switch are changed to the first state. and a state controller that maintains the The power supply system is applied to a vehicle equipped with an engine, and supplies power to a starter (16) that imparts rotational force to the engine when the engine is started,
said connection point is a first connection point (P1);
In the first electrical path, the first switch is provided between the first connection point and the first storage battery,
The starter is connected to a second connection point (P2) between the first switch and the first storage battery,
When the second determination unit determines that the detected current is greater than the second threshold value, the state control unit controls the first switch and the first switch under the condition that the one switch is the second switch. 2. The control device according to claim 1, wherein the state of a second switch is switched to the second state.

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