JP7532105B2 - Control device and control method for power supply system - Google Patents

Description

The present invention relates to a control device and a control method for a power supply system.

Conventionally, a technology has been proposed that, if a relay connected to a battery becomes stuck, controls the relay or a motor generator connected to the battery to prevent a voltage drop in the battery (see, for example, Patent Document 1).

International Publication No. 2014/017198

However, the conventional technology left room for improvement in terms of preventing current from concentrating in the switch part that constitutes the relay when the relay becomes stuck.

The present invention has been made in consideration of the above, and aims to provide a control device and control method for a power supply system that can prevent current from concentrating in a switch that constitutes a relay when the relay becomes stuck.

In order to solve the above problems and achieve the object, the present invention provides a control device for a power supply system in which a first battery, a second battery, and a generator are connected in parallel, a first relay is interposed between the first battery and the generator, a second relay is interposed between the second battery and the generator, and the first relay and the second relay each include a plurality of switch units connected in parallel, the control device comprising a detection unit, a switch control unit, and a power generation control unit. The detection unit detects a stuck-on state in the plurality of switch units. When a stuck-on state is detected by the detection unit, the switch control unit turns on all of the plurality of switch units that are connected in parallel to at least the switch unit in which the stuck-on state is detected. The power generation control unit controls the generator according to the position of the switch unit in which the stuck-on state is detected among the plurality of switch units.

According to the present invention, if the relay becomes stuck, it is possible to prevent current from concentrating in the switch portion that constitutes the relay.

FIG. 1 is a block diagram showing an example of the configuration of a power supply system including a control device according to an embodiment. FIG. 2 is an explanatory diagram illustrating an example of a circuit configuration of the first relay. FIG. 3 is an explanatory diagram illustrating an example of a circuit configuration of the second relay. FIG. 4 is a block diagram showing the configuration of a power supply system including a control device. FIG. 5 is a flowchart showing a process executed by the control device when the switch is stuck on. FIG. 6 is a flowchart showing a process executed by the control device when the switch is stuck off.

Below, an embodiment of a control device and a control method for a power supply system disclosed in the present application will be described in detail with reference to the attached drawings. Note that the present invention is not limited to the embodiment described below.

The following description will be given with an example of the control device controlling a power supply system mounted on a vehicle such as an HEV (Hybrid Electric Vehicle), μHEV (Micro Hybrid Electric Vehicle), or PHEV (Plug-in Hybrid Electric Vehicle). Note that the object controlled by the control device is not limited to a power supply system mounted on a vehicle, and may be a power supply system mounted on any device.

(Overall configuration of power supply system including control device)
First, a power supply system including a control device according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of a power supply system including a control device according to an embodiment.

As shown in FIG. 1, the power supply system 1 includes a battery pack 10, a generator 11, a lead battery 12, an auxiliary device 13, and a control device 30. The battery pack 10 includes a LIB (Lithium-Ion rechargeable Battery) 15, a first relay 16, a second relay 18, and a monitoring device 20.

In this way, the power supply system 1 is a dual power supply system equipped with two batteries, the lead battery 12 and the LIB 15. Note that the power supply system 1 is not limited to a dual power supply system with duplicated batteries, and the number of batteries may be three or more.

The generator 11 is a device that generates electric power using the rotation of an engine (not shown) as a power source. In addition, when the vehicle decelerates, it generates regenerative electric power by regenerative braking. The generator 11 is also called an alternator or generator. The generator 11 may also function as a starting device (starter) that starts the engine. In other words, the generator 11 may be an ISG (Integrated Starter Generator).

The generator 11 may also generate power in response to, for example, an instruction from the control device 30. Then, for example, the generator 11 supplies the generated power to the lead battery 12 or the LIB15 to charge the lead battery 12 or the LIB15.

The lead battery 12 is a secondary battery that uses lead for the electrodes. The lead battery 12 serves as the main power source for the auxiliary equipment 13 mounted on the vehicle, for example. The lead battery 12 is an example of a first battery.

The auxiliary equipment 13 is an electrical device (load) mounted on the vehicle. For example, the auxiliary equipment 13 is a navigation device, an audio device, an air conditioner, etc., but these are examples and are not limited to these. The auxiliary equipment 13 can receive power from the lead battery 12 or the LIB 15.

The LIB15 of the battery pack 10 is a secondary battery that charges or discharges, and serves as an auxiliary power source for the lead battery 12, for example. Therefore, the LIB15 serves as an auxiliary power source for the auxiliary device 13. The LIB15 is an example of a second battery.

The first battery, which is the lead battery 12, and the second battery, which is the LIB15, may be other types of secondary batteries. Also, the LIB15 may be used as the main power source, and the lead battery 12 may be used as the auxiliary power source.

The lead battery 12, LIB15, generator 11, and auxiliary equipment 13 are connected in parallel. For example, the generator 11 and the lead battery 12 are connected via a first path (current path) L1. LIB15 is connected to the generator 11 via a second path (current path) L2 connected to the first path L1 and the first path L1. The auxiliary equipment 13 is connected to the lead battery 12 via a third path (current path) L3 connected to the first path L1 and the first path L1. The auxiliary equipment 13 is also connected to LIB15 via the third path L3, the first path L1, and the second path L2.

The first relay 16 and the second relay 18 are switches (relays) that control the shorting and opening of the circuit. The first relay 16 is interposed between the lead battery 12 and the generator 11. Specifically, the first relay 16 is connected to a first path L1 that connects the generator 11 and the lead battery 12. More specifically, the first relay 16 is interposed in the first path L1 between a position where the second path L2 is connected and a position where the third path L3 is connected. The detailed configuration of the first relay 16 will be described later with reference to FIG. 2.

The second relay 18 is interposed between the LIB 15 and the generator 11. Specifically, the second relay 18 is connected to a second path L2 that connects the generator 11 and the LIB 15. The detailed configuration of the second relay 18 will be described later with reference to FIG. 3. The opening and closing of the first relay 16 and the second relay 18 may be controlled by the control device 30 or may be controlled by the monitoring device 20.

The monitoring device 20 monitors the state of the battery pack 10. The monitoring device 20 is realized by a microcomputer or a monitoring integrated circuit (IC), etc.

For example, the monitoring device 20 monitors the state of LIB15. In detail, the monitoring device 20 detects the charge/discharge current and battery voltage of LIB15 based on the output of a current sensor and a voltage sensor (not shown) connected to LIB15. The monitoring device 20 also calculates the SOC (State Of Charge) of LIB15 based on the current and voltage of LIB15. The monitoring device 20 then outputs a signal indicating the detected current and voltage of LIB15, the calculated SOC, etc. to the control device 30.

The monitoring device 20 also monitors the state of the first relay 16. For example, the monitoring device 20 detects the potential difference across the shunt resistor 173 (see FIG. 2; described below) included in the first relay 16, and measures the current flowing through the shunt resistor 173 by calculating the current value from the voltage value based on the detected potential difference. The monitoring device 20 then outputs a signal indicating the voltage and current of the first relay 16 (more precisely, the potential difference (voltage) and current across the shunt resistor 173) to the control device 30.

The monitoring device 20 also determines the on/off state of the switch section 17 (see FIG. 2; described later) that constitutes the first relay 16 based on the terminal voltages and currents of the first relay 16, and outputs signals indicating the terminal voltages and currents of the first relay 16 and the determination results to the control device 30.

The monitoring device 20 also monitors the state of the second relay 18. For example, the monitoring device 20 detects the potential difference across the shunt resistor 193 (see FIG. 3, described below) included in the second relay 18, and measures the current flowing through the shunt resistor 193 by calculating the current value from the voltage value based on the detected potential difference. The monitoring device 20 then outputs a signal indicating the voltage and current of the second relay 18 (more precisely, the potential difference (voltage) and current across the shunt resistor 193) to the control device 30.

The monitoring device 20 also determines the on/off state of the switch section 19 (see FIG. 3, described below) constituting the second relay 18 based on the terminal voltages and currents of the second relay 18, and outputs signals indicating the terminal voltages and currents of the second relay 18 and the determination results to the control device 30. Note that, although the on/off state of the first and second relays 16, 18 is determined by the monitoring device 20 in the above description, this is not limited to the above, and may be determined by the control device 30, for example.

The monitoring device 20 can also control the on/off states of the first and second relays 16, 18 in response to an on signal or an off signal (described later) of the first and second relays 16, 18 input from the control device 30. Note that in the above description, the monitoring device 20 controls the on/off states of the first and second relays 16, 18, but this is not limited thereto. For example, a relay control device (not shown) may be provided in the battery pack 10, and the relay control device may control the on/off states of the first and second relays 16, 18.

The control device 30 controls the entire power supply system 1. In other words, the control device 30 is a host ECU (Electronic Control Unit). For example, signals indicating the states of the LIB 15, the first relay 16, and the second relay 18 are input to the control device 30 from the monitoring device 20. The control device 30 also detects the charge/discharge current and battery voltage of the lead battery 12 based on the output of a current sensor and a voltage sensor (not shown) connected to the lead battery 12. The control device 30 may also calculate the SOC of the lead battery 12 based on the current and voltage of the lead battery 12.

The control device 30 acquires the vehicle status and the like from time to time, and opens and closes the first relay 16 and the second relay 18 based on the vehicle status, the state of the LIB 15, the state of the lead battery 12, the states of the first and second relays 16 and 18, and controls the charging and discharging of the lead battery 12 and the LIB 15. The control device 30 also controls the operation of the generator 11 according to the vehicle status and the like. The control device 30 may also control the operation of the auxiliary equipment 13 and the like according to the vehicle status and the like.

The control device 30 is configured to prevent current from concentrating in the switch section 17 (see FIG. 2) constituting the first relay 16 or the switch section 19 (see FIG. 3) constituting the second relay 18 in the event of sticking in the first relay 16 or the second relay 18, as will be described later.

(Configuration of the first relay)
Next, the configuration of the first relay 16 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing an example of a circuit configuration of the first relay 16. As shown in Fig. 2, the first relay 16 is configured by connecting a plurality of switch units 17 in parallel.

Note that while FIG. 2 shows an example in which there are three switch units 17, this is not limiting. That is, for example, the first relay 16 may have two switch units 17 connected in parallel, or four or more switch units 17 connected in parallel. Below, the three switch units 17 may be referred to as "first switch unit 17a," "second switch unit 17b," and "third switch unit 17c," but when there is no need to distinguish between them, they will be referred to as "switch unit 17."

The switch unit 17 includes a pair of transistors 171 and 172 and a shunt resistor 173. Note that the transistors 171 and 172 may be, for example, MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors), but are not limited to this.

A pair of transistors 171, 172 are connected in series. For example, one end of transistor 171 is connected to generator 11, and the other end is connected to transistor 172. One end of transistor 172 is connected to transistor 171, and the other end is connected to lead battery 12.

Transistors 171 and 172 each have a switching element and a body diode, and the switching element and the body diode are connected in parallel. The body diodes of transistors 171 and 172 are arranged in the opposite direction. For example, the body diode of transistor 171 has an anode connected to transistor 172 and a cathode connected to generator 11. The body diode of transistor 172 has an anode connected to transistor 171 and a cathode connected to lead battery 12. This prevents current from flowing between the pair of transistors 171 and 172 when switch unit 17 is turned off (more precisely, when the switching elements of transistors 171 and 172 are turned off).

The shunt resistor 173 is connected in series between the transistor 171 and the transistor 172. As described above, the potential difference between both ends of the shunt resistor 173 is detected by the monitoring device 20, and the current flowing through the shunt resistor 173 is measured from the voltage value based on the detected potential difference. The shunt resistor 173 may be connected to a pull-down resistor. The shunt resistor 173 may also be connected to the generator 11 side of the transistor 171 or the lead battery 12 side of the transistor 172. In the above, the shunt resistor 173 is used to detect the current, but this is not limited to the above, and the current may be detected using other types of current sensors, such as a Hall current sensor.

(Configuration of the second relay)
Next, the configuration of the second relay 18 will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram showing an example of a circuit configuration of the second relay 18. As shown in Fig. 3, the second relay 18 is configured by connecting a plurality of switch units 19 in parallel.

Note that while FIG. 3 shows an example in which there are four switch units 19, this is not limiting. That is, for example, the second relay 18 may have two or three switch units 19 connected in parallel, or may have five or more switch units 19 connected in parallel. Below, the four switch units 19 may be referred to as "first switch unit 19a," "second switch unit 19b," "third switch unit 19c," and "fourth switch unit 19d," but when there is no need to distinguish between them, they will be referred to as "switch units 19."

The switch unit 19 includes a pair of transistors 191 and 192 and a shunt resistor 193. Note that the transistors 191 and 192 may be, for example, MOSFETs, but are not limited to these.

A pair of transistors 191 and 192 are connected in series. For example, one end of transistor 191 is connected to generator 11, and the other end is connected to transistor 192. One end of transistor 192 is connected to transistor 191, and the other end is connected to LIB15.

Transistors 191 and 192 each have a switching element and a body diode, and the switching element and the body diode are connected in parallel. The body diodes of transistors 191 and 192 are arranged in the opposite directions. For example, the body diode of transistor 191 has an anode connected to transistor 192 and a cathode connected to generator 11. The body diode of transistor 192 has an anode connected to transistor 191 and a cathode connected to LIB15. This prevents current from flowing between the pair of transistors 191 and 192 when switch unit 19 is turned off (more precisely, when the switching elements of transistors 191 and 192 are turned off).

The shunt resistor 193 is connected in series between the transistor 191 and the transistor 192. As described above, the potential difference between both ends of the shunt resistor 193 is detected by the monitoring device 20, and the current flowing through the shunt resistor 193 is measured from the voltage value based on the detected potential difference. The shunt resistor 193 may be connected to a pull-down resistor. The shunt resistor 193 may also be connected to the generator 11 side of the transistor 191 or the LIB15 side of the transistor 192. In the above, the current is detected using the shunt resistor 193, but this is not limited to the above, and the current may be detected using other types of current sensors, such as a Hall-type current sensor.

(Regarding adhesion)
Next, a description will be given of the sticking of the first relay 16 and the second relay 18. First, the sticking of the first relay 16 will be described with reference to FIG.

The first relay 16 may become stuck. More specifically, the multiple switch sections 17 that make up the first relay 16 may become stuck. Such sticking may be classified as "on sticking," in which the switch section 17 is stuck in the on state, or "off sticking," in which the switch section 17 is stuck in the off state.

When the above-mentioned stuck-on or stuck-off occurs in the switch section 17, for example, there is a risk that current will concentrate and flow in some of the multiple switch sections 17. To explain in detail, as an example, when the transistor 171 of the first switch section 17a is "stuck-on", even if an off signal is output from the control device 30 (see FIG. 1) or the monitoring device 20 (see FIG. 1) to the first relay 16, the transistor 171 of the first switch section 17a is not turned off. At this time, the transistor 172 of the first switch section 17a is turned off, but has a body diode. Therefore, as shown by the arrow A in FIG. 2, the current flows through the switching element of the transistor 171 and the body diode of the transistor 172. In this way, when the transistor 171 of the first switch section 17a is stuck-on and an off signal is output to the first relay 16, there is a risk that current will concentrate and flow in the first switch section 17a in which the stuck-on has occurred, among the multiple switch sections 17.

If the "stuck on" occurring in the transistor 171 of the first switch section 17a is due to, for example, a short circuit, the on resistance of the transistor 171 may increase. In such a case, when an on signal is output from the control device 30 or the monitoring device 20 to the first relay 16, it becomes difficult for current to flow through the transistor 171 of the first switch section 17a, and there is a risk that the current will concentrate and flow through the remaining second switch section 17b and third switch section 17c. In this way, when the transistor 171 of the first switch section 17a becomes stuck on and an on signal is output to the first relay 16, there is a risk that the current will concentrate and flow through the second switch section 17b and third switch section 17c that are normal among the multiple switch sections 17.

Next, as an example, if the transistor 171 of the first switch section 17a is "stuck off", the transistor 171 of the first switch section 17a will not be turned on even if an on signal is output from the control device 30 or the monitoring device 20 to the first relay 16. Therefore, in the first relay 16, no current flows through the first switch section 17a, but current flows through the remaining second switch section 17b and third switch section 17c. In this way, if the transistor 171 of the first switch section 17a is stuck off, there is a risk that current will flow concentratedly through the normal second switch section 17b and third switch section 17c among the multiple switch sections 17, rather than through the first switch section 17a that is stuck off.

Next, the sticking of the second relay 18 will be described with reference to FIG. 3. As an example, if the transistor 191 of the first switch section 19a is "stuck on", the transistor 191 of the first switch section 19a is not turned off even if an off signal is output from the control device 30 or the monitoring device 20 to the second relay 18. At this time, the transistor 192 of the first switch section 19a is turned off, but has a body diode. Therefore, as shown by the arrow B in FIG. 3, the current flows through the switching element of the transistor 191 and the body diode of the transistor 192. In this way, if the transistor 191 of the first switch section 19a is stuck on and an off signal is output to the second relay 18, there is a risk that the current will concentrate and flow in the first switch section 19a in which the stuck on state has occurred, among the multiple switch sections 19.

In addition, if the second relay 18 is stuck on, the lead battery 12 may not be charged efficiently. To explain in detail, for example, when the control device 30 actively charges the lead battery 12, the control device 30 electrically connects the generator 11 and the lead battery 12 by turning on the first relay 16 and turning off the second relay 18. Here, if the second relay 18 is stuck on, the generator 11 is also electrically connected to the LIB 15 (see arrow B in FIG. 3). Since the internal resistance of the LIB 15 is smaller than the internal resistance of the lead battery 12, the current from the generator 11 flows to the LIB 15 side, and the lead battery 12 cannot be charged efficiently, and there is a risk that the lead battery 12 will be depleted (in other words, there is a risk that the battery will run out). Therefore, the control device 30 according to this embodiment is configured to prevent the lead battery 12 from being depleted, which will be described later.

Next, as an example, if the transistor 191 of the first switch section 19a is "stuck off," the transistor 191 of the first switch section 19a will not be turned on even if an on signal is output from the control device 30 or the monitoring device 20 to the second relay 18. Therefore, in the second relay 18, no current flows through the first switch section 19a, but current flows through the remaining second switch section 19b, third switch section 19c, and fourth switch section 19d. In this way, if the transistor 191 of the first switch section 19a is stuck off, there is a risk that current will flow concentratedly through the normal second to fourth switch sections 19b to 19d, rather than through the first switch section 19a that is stuck off.

(Configuration of the control device)
Therefore, the control device 30 is configured to suppress current concentration in the switch section 17 of the first relay 16 or the switch section 19 of the second relay 18 when sticking occurs in the first relay 16 or the second relay 18 as described above.

The configuration of the power supply system 1 including the control device 30 according to the embodiment will be described in detail below with reference to FIG. 4. FIG. 4 is a block diagram showing the configuration of the power supply system 1 including the control device 30 according to the embodiment. Note that in FIG. 4, only the components necessary to explain the features of this embodiment are shown as functional blocks, and descriptions of general components are omitted.

In other words, each component shown in FIG. 4 is a functional concept, and does not necessarily have to be physically configured as shown. For example, the specific form of distribution and integration of each functional block is not limited to that shown, and all or part of it can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

As shown in FIG. 4, the control device 30 of the power supply system 1 includes an input unit 31, an output unit 32, a control unit 40, and a memory unit 50. The control unit 40 includes a detection unit 41, a switch control unit 42, and a power generation control unit 43.

The input unit 31 receives signals indicating the current and voltage of the lead battery 12 from a current sensor and a voltage sensor connected to the lead battery 12, and outputs these signals to the control unit 40. The input unit 31 also receives signals indicating the current and voltage of the LIB 15, the calculated SOC, etc. from the monitoring device 20, and outputs these signals to the control unit 40.

The input unit 31 also receives signals from the monitoring device 20 indicating the potential difference (voltage) and current across the shunt resistor 173 of the first relay 16, and outputs these signals to the control unit 40. The input unit 31 also receives signals from the monitoring device 20 indicating the potential difference (voltage) and current across the shunt resistor 193 of the second relay 18, and outputs these signals to the control unit 40. The input unit 31 also receives signals from the monitoring device 20 indicating the terminal voltages and currents of the first and second relays 16, 18, and the on/off states of the first and second relays 16, 18, which are the above-mentioned judgment results, and outputs these signals to the control unit 40.

The output unit 32 outputs a signal for turning on (conducting) or off (cutting off) the first relay 16 to the monitoring device 20. An on signal for turning on the first relay 16 is a signal that turns on all of the switch units 17 of the first relay 16. An off signal for turning off the first relay 16 is a signal that turns off all of the switch units 17 of the first relay 16.

The output unit 32 outputs a signal for turning on (conducting) or off (cutting off) the second relay 18 to the monitoring device 20. An on signal for turning on the second relay 18 is a signal that turns on all of the switch units 19 of the second relay 18. An off signal for turning off the second relay 18 is a signal that turns off all of the switch units 19 of the second relay 18. As described above, the monitoring device 20 controls the on/off state of the first and second relays 16, 18 in response to the on or off signal of the first and second relays 16, 18 that is input.

The output unit 32 outputs a signal to the generator 11 to control the generator 11. The operation of the generator 11 is controlled by this signal, which will be described in detail later.

The memory unit 50 is a storage device such as a data flash, non-volatile memory, or a register, and stores various programs, information, etc.

The control unit 40 includes, for example, a computer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), input/output ports, and various other circuits.

The computer's CPU functions as the detection unit 41, switch control unit 42, and power generation control unit 43 of the control unit 40, for example, by reading and executing a program stored in the ROM.

In addition, at least some or all of the detection unit 41, switch control unit 42, and power generation control unit 43 of the control unit 40 can be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

The detection unit 41 can detect sticking in the multiple switch sections 17 of the first relay 16 and the multiple switch sections 19 of the second relay 18.

Specifically, the detection unit 41 can detect "stuck on" in the multiple switch units 17 of the first relay 16. For example, when an off signal is output to the first relay 16 and a signal indicating that a potential difference (voltage) is occurring across the shunt resistor 173 of the first relay 16 (e.g., a signal indicating the voltage of the generator 11) is input, the detection unit 41 can detect that the switch unit 17 including the shunt resistor 173 is stuck on because the switch unit 17 is not turned off (shut off).

In the above description, the detection unit 41 detects the stuck-on state based on the potential difference between both ends of the shunt resistor 173, but this is not limited to the above. That is, for example, the detection unit 41 may detect the stuck-on state of the switch unit 17 including the shunt resistor 173 when a signal indicating that a current is flowing through the shunt resistor 173 is input while an off signal is being output to the first relay 16, or may detect the stuck-on state using other methods.

The detection unit 41 can detect "stuck on" in the multiple switch units 19 of the second relay 18. For example, when an off signal is output to the second relay 18 and a signal indicating that a potential difference (voltage) is occurring across the shunt resistor 193 of the second relay 18 (e.g., a signal indicating the voltage of the generator 11) is input, the detection unit 41 can detect that the switch unit 19 including the shunt resistor 193 is stuck on because the switch unit 19 is not turned off (shut off).

The detection unit 41 may detect the on-stuck state by other methods, such as detecting the on-stuck state of the switch unit 19 including the shunt resistor 193 when a signal indicating that a current is flowing through the shunt resistor 193 is input while an off signal is being output to the second relay 18.

The detection unit 41 can detect "stuck off" in the multiple switch units 17 of the first relay 16. For example, when an on signal is output to the first relay 16 and a signal indicating that a potential difference (voltage) is occurring across the shunt resistor 173 of the first relay 16 is not input, i.e., when the potential difference is zero, the detection unit 41 can detect that the switch unit 17 including the shunt resistor 173 is not on (conducting), and therefore the switch unit 17 is stuck off.

In the above description, the detection unit 41 detects the stuck-off state based on the potential difference between both ends of the shunt resistor 173, but this is not limited to the above. That is, for example, the detection unit 41 may detect the stuck-off state of the switch unit 17 including the shunt resistor 173 by other methods, such as detecting the stuck-off state of the switch unit 17 including the shunt resistor 173 when an on signal is output to the first relay 16 and a signal indicating that a current is flowing through the shunt resistor 173 is not input, i.e., when the current value is zero.

The detection unit 41 can detect "stuck off" in the multiple switch units 19 of the second relay 18. For example, when an on signal is output to the second relay 18 and a signal indicating that a potential difference exists across the shunt resistor 193 of the second relay 18 is not input (i.e., the potential difference is zero), the detection unit 41 can detect that the switch unit 19 is stuck off because the switch unit 19 including the shunt resistor 193 is not on (conducting).

The detection unit 41 may detect the switch unit 19 including the shunt resistor 193 being stuck in the off state by other methods, such as detecting the switch unit 19 being stuck in the off state when an on signal is output to the second relay 18 and a signal indicating that a current is flowing through the shunt resistor 193 is not input (i.e., when the current value is 0).

When a sticking is detected, the detection unit 41 outputs a sticking detection signal to the switch control unit 42 and the power generation control unit 43, which indicates the positions of the switch unit 17 and the switch unit 19 where the sticking is detected and the type of sticking, i.e., whether the sticking is an on-sticking or an off-sticking.

The switch control unit 42 controls the switch unit 17 of the first relay 16 and the switch unit 19 of the second relay 18 based on the sticking detection signal. Similarly, the power generation control unit 43 controls the generator 11 based on the sticking detection signal. In detail, the power generation control unit 43 controls the generator 11 according to the type of sticking and the position of the switch unit 17, 19 in which the on sticking is detected among the multiple switch units 17, 19.

As a result, in this embodiment, if the first relay 16 or the second relay 18 becomes stuck, it is possible to prevent current from concentrating in the switch units 17 and 19 that constitute the first and second relays 16 and 18. This will be explained in detail below.

(When the switch portion 17 of the first relay 16 is stuck on)
First, a description will be given of a case where the switch section 17 of the first relay 16 is stuck on. The switch control section 42 turns on all of the multiple switch sections 17, 19 that are connected in parallel to at least the switch section 17 in which the stuck on state has been detected.

Specifically, in the example of FIG. 2 described above, if the first switch section 17a (transistor 171) is stuck on, there is a risk that current will concentrate and flow through the first switch section 17a where the stuck on state has occurred. Therefore, the switch control section 42 outputs an on signal to the first relay 16 via the output section 32, and turns on all of the second switch section 17b and the third switch section 17c that are connected in parallel with the first switch section 17a where the stuck on state has occurred. To be precise, the switch control section 42 turns on all of the switch sections 17, including the first switch section 17a where the stuck on state has occurred.

As a result, the current flowing through the first relay 16 is dispersed to the second switch section 17b and the third switch section 17c, making it possible to prevent current from concentrating in the first switch section 17a where the stuck-on state has occurred. Furthermore, since the current is prevented from concentrating in the first switch section 17a, for example, heat generation is suppressed, and as a result, the occurrence of breakdowns due to heat generation can also be suppressed.

When the switch unit 17 is stuck on, the switch control unit 42 can control the second relay 18 based on the vehicle conditions and the state of the LIB 15, in the same way as when the switch unit 17 is not stuck on, but is not limited to this.

As described above, the on-resistance of the transistor 171 of the first switch section 17a may increase due to the transistor 171 being stuck on. In this case, when an on signal is output to the first relay 16, it is difficult for current to flow through the first switch section 17a, and there is a risk that the current will flow concentratedly through the second and third switch sections 17b and 17c.

Therefore, when a stuck-on state is detected in the switch section 17 included in the first relay 16, in other words, when the position where the stuck-on state is detected is the switch section 17 of the first relay 16, the power generation control section 43 executes power generation control for the generator 11 to suppress the amount of power generation.

For example, when the generator 11 supplies power to the lead battery 12 for charging, or when the generator 11 supplies power to the auxiliary device 13, the power generation control unit 43 suppresses the amount of power generated by the generator 11 so that the current allowed by the second and third switch units 17b and 17c that are not stuck on flows through the second and third switch units 17b and 17c.

In other words, the power generation control unit 43 suppresses the amount of power generation by the generator 11 so that the current flowing through the remaining switch units 17, excluding the switch unit 17 in which the stuck-on state has occurred, is within the range of the current allowed by the remaining switch unit 17.

This makes it possible to prevent excessive current from concentrating and flowing in normal switch sections 17 (second and third switch sections 17b and 17c in this case) that are not stuck on. Furthermore, since excessive current is prevented from concentrating and flowing in normal switch sections 17 (second and third switch sections 17b and 17c), for example, heat generation is reduced, and as a result, the occurrence of breakdowns due to heat generation can also be prevented.

(When the switch portion 19 of the second relay 18 is stuck on)
Next, a description will be given of a case where the switch section 19 of the second relay 18 is stuck on. The switch control section 42 turns on all of the switch sections 17, 19 that are connected in parallel to at least the switch section 19 in which the stuck on state has been detected.

Specifically, in the example of FIG. 3 described above, if the first switch section 19a (transistor 191) is stuck on, there is a risk that current will concentrate and flow through the first switch section 19a where the stuck on state has occurred. Therefore, the switch control section 42 outputs an on signal to the second relay 18 via the output section 32, and turns on all of the second to fourth switch sections 19b to 19d that are connected in parallel with the first switch section 19a where the stuck on state has occurred. To be precise, the switch control section 42 turns on all of the switch sections 19, including the first switch section 19a where the stuck on state has occurred.

As a result, the current flowing through the second relay 18 is distributed among the second to fourth switch sections 19b to 19d, making it possible to prevent current from concentrating in the first switch section 19a where the stuck-on state has occurred. Furthermore, since current is prevented from concentrating in the first switch section 19a, it becomes less likely to generate heat, for example, and as a result, it is possible to prevent the occurrence of breakdowns caused by heat.

Furthermore, as described above, if the second relay 18 is stuck on, the lead battery 12 cannot be charged efficiently. That is, even if the first relay 16 is turned on and the second relay 18 is turned off, the generator 11 and the LIB 15 are electrically connected by the second relay 18 that is stuck on. Since the internal resistance of the LIB 15 is smaller than the internal resistance of the lead battery 12, the current from the generator 11 flows to the LIB 15 side, and the lead battery 12 cannot be charged efficiently, which may result in the lead battery 12 being depleted (the battery running out).

Therefore, when the power generation control unit 43 detects that the switch unit 19 included in the second relay 18 is stuck on, in other words, when the position where the stuck on is detected is the switch unit 19 of the second relay 18, the power generation control unit 43 executes power generation control for the generator 11 so that the voltage of the LIB 15 is higher than the voltage of the lead battery 12.

As an example, the power generation control unit 43 controls the generator 11 so that the SOC of the LIB 15 is maintained at a relatively high value. Note that the above-mentioned relatively high value refers to a value higher than the target SOC (the target SOC under normal conditions) that is the target when the switch unit 19 is not stuck on, for example, but is not limited to this and may be set to any value.

That is, in the case of LIB15, the voltage increases as the SOC increases. Therefore, by maintaining the SOC at a relatively high value, the power generation control unit 43 is able to maintain the voltage of LIB15 at a high value. When the voltage of LIB15 is maintained at a voltage higher than that of the lead battery 12, the current from the generator 11 tends to flow to the lead battery 12, which has a lower voltage, and as a result, it is possible to prevent the lead battery 12 from running out (running down).

In addition, if the stuck-on state of the transistor 191 of the first switch section 19a is caused by, for example, a short circuit, the on resistance of the transistor 191 may increase. In this case, when an on signal is output to the second relay 18, it is difficult for current to flow through the first switch section 19a, and there is a risk that the current will flow concentratedly through the second to fourth switch sections 19b to 19d.

Therefore, for example, when charging the LIB15, if the power generation control unit 43 detects that the switch unit 19 included in the second relay 18 is stuck on, in other words, if the location where the stuck on is detected is the switch unit 19 of the second relay 18, the power generation control unit 43 may execute power generation control for the generator 11 to suppress the amount of power generation.

For example, when supplying power from the generator 11 to the LIB 15 for charging, the power generation control unit 43 suppresses the amount of power generation by the generator 11 so that the current allowed by the second to fourth switch units 19b to 19d that are not stuck on flows through the second to fourth switch units 19b to 19d.

In other words, the power generation control unit 43 suppresses the amount of power generation by the generator 11 so that the current flowing through the remaining switch units 19, excluding the switch unit 19 in which the stuck-on state has occurred, is within the range of the current allowed by the remaining switch unit 19.

In this way, the power generation control unit 43 may charge the LIB 15 until the SOC reaches a relatively high value while suppressing the amount of power generation by the generator 11, thereby maintaining the SOC in a relatively high state.

This makes it possible to prevent excessive current from concentrating and flowing through normal switch sections 19 (second to fourth switch sections 19b to 19d in this case) that are not stuck on, and also prevents depletion of the lead battery 12. Furthermore, since excessive current is prevented from concentrating and flowing through normal switch sections 19 (second to fourth switch sections 19b to 19d), for example, heat generation is suppressed, and as a result, the occurrence of breakdowns due to heat generation can also be suppressed.

(When the switch unit 17 of the first relay 16 is stuck off)
Next, a description will be given of a case where the switch unit 17 of the first relay 16 is stuck off. When the switch control unit 42 detects that the switch unit 17 is stuck off, the switch control unit 42 turns on all of the multiple switch units 17 included in the first relay 16, and turns off all of the multiple switch units 19 included in the second relay 18.

When the power generation control unit 43 detects that the switch unit 17 included in the first relay 16 is stuck off, the power generation control unit 43 executes power generation control to suppress the amount of power generated by the generator 11. This makes it possible to prevent excessive current from concentrating and flowing through the switch unit 17 of the first relay 16.

Specifically, as described above, when the first switch section 17a is stuck off, the first switch section 17a is not turned on even if an on signal is output from the switch control section 42 to the first relay 16. Therefore, there is a risk that current will concentrate and flow through the remaining second and third switch sections 17b and 17c.

Therefore, when the power generation control unit 43 detects that the switch unit 17 of the first relay 16 is stuck in the off state, in other words, when the position where the stuck-off state is detected is the switch unit 17 of the first relay 16, the power generation control unit 43 suppresses the amount of power generation of the generator 11.

For example, when the generator 11 supplies power to the lead battery 12 for charging, or when the generator 11 supplies power to the auxiliary device 13, the power generation control unit 43 suppresses the amount of power generated by the generator 11 so that the current allowed by the second and third switch units 17b and 17c that are not stuck in off state flows through the second and third switch units 17b and 17c.

In other words, the power generation control unit 43 suppresses the amount of power generation by the generator 11 so that the current flowing through the remaining switch units 17, excluding the switch unit 17 in which the stuck-off state has occurred, is within the range of the current allowed by the remaining switch unit 17.

This makes it possible to prevent excessive current from concentrating and flowing in normal switch sections 17 (second and third switch sections 17b and 17c in this case) that are not stuck-off. Furthermore, since excessive current is prevented from concentrating and flowing in normal switch sections 17 (second and third switch sections 17b and 17c), for example, heat generation is reduced, and as a result, the occurrence of breakdowns due to heat generation can also be prevented.

As described above, the switch control unit 42 can turn off all of the switch units 19 of the second relay 18 to cut off the electrical connection between the LIB 15 and the lead battery 12. This can prevent, for example, unintended charging and discharging between the LIB 15 and the lead battery 12 from affecting the control that suppresses the amount of power generation.

(When the switch unit 19 of the second relay 18 is stuck off)
Next, a case where the switch unit 19 of the second relay 18 is stuck off will be described. When the switch control unit 42 detects that the switch unit 19 is stuck off, the switch control unit 42 turns on all of the switch units 17 included in the first relay 16, and turns off all of the switch units 19 included in the second relay 18. This makes it possible to prevent current from concentrating and flowing in the switch unit 19 of the second relay 18.

Specifically, as described above, if the first switch section 19a is stuck off, the first switch section 19a will not be turned on even if an on signal is output from the switch control section 42 to the second relay 18, and current may be concentrated and flow through the remaining second to fourth switch sections 19b to 19d.

The switch control unit 42 is configured to turn off all switch units 19 of second relays 18 in which the stuck-off state has occurred, thereby making it possible to prevent current from concentrating in the switch units 19 of the second relays 18. Furthermore, since current is prevented from concentrating in the switch units 19, they are less likely to generate heat, for example, and as a result, it is possible to prevent the occurrence of breakdowns caused by heat.

Even if the second relay 18 is turned off, the first relay 16 is turned on, so the lead battery 12 can function as the main power source.

(Processing procedure of the control device 30)
Next, a process performed by the control device 30 according to the embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are both flowcharts showing the process performed by the control device 30. For ease of understanding, Fig. 5 shows the process when the switch is stuck on, and Fig. 6 shows the process when the switch is stuck off.

First, referring to FIG. 5, the control unit 40 of the control device 30 determines whether or not a stuck-on state is detected in the multiple switch units 17, 19 (step S100). If the control unit 40 determines that a stuck-on state is not detected (step S100, No), the process ends.

On the other hand, when it is determined that the on-fixation is detected (step S100, Yes), the control unit 40 determines whether the detected on-fixation is the switch unit 17 of the first relay 16 (step S101). When it is determined that the on-fixation is the switch unit 17 of the first relay 16 (step S101, Yes), the control unit 40 turns on all of the switch units 17 of the first relay 16 (step S102). This electrically connects the generator 11 and the lead battery 12. Next, the control unit 40 executes power generation control for the generator 11 to suppress the amount of power generation (step S103). Note that, in FIG. 5, an example in which the process is executed in the order of step S102 and step S103 is shown, but this is not limited thereto. For example, the control unit 40 may execute the process in the order of step S103 and step S102, or may execute the process of step S102 and step S103 simultaneously.

When it is determined that the switch section 17 of the first relay 16 is not stuck on (step S101, No), i.e., when the switch section 19 of the second relay 18 is stuck on, the control section 40 turns on all of the switch sections 19 of the second relay 18 (step S104). This electrically connects the generator 11 and the LIB 15. Next, the control section 40 turns on all of the switch sections 17 of the first relay 16 (step S105). This electrically connects the generator 11 and the lead battery 12.

Next, the control unit 40 executes power generation control on the generator 11 so that the voltage of the LIB 15 is higher than the voltage of the lead battery 12 (step S106). The control unit 40 also executes power generation control on the generator 11 so as to suppress the amount of power generation (step S107).

Note that the order of steps S104 to S107 shown in FIG. 5 is merely an example and is not limited to this. In other words, the control unit 40 may execute the processes of steps S104 to S107 in any order, or may execute some or all of the processes of steps S104 to S107 simultaneously.

Next, referring to FIG. 6, the control unit 40 determines whether or not a stuck-off state has been detected in the multiple switch units 17 and 19 (step S200). If the control unit 40 determines that a stuck-off state has not been detected (step S200, No), the process ends.

On the other hand, if the control unit 40 determines that a stuck-off state has been detected (step S200, Yes), it determines whether the detected stuck-off state is the switch unit 17 of the first relay 16 (step S201). If the control unit 40 determines that the stuck-off state is the switch unit 17 of the first relay 16 (step S201, Yes), it turns on all of the switch units 17 of the first relay 16 (step S202). This electrically connects the generator 11 and the lead battery 12.

Next, the control unit 40 turns off all of the switch units 19 of the second relays 18 (step S203). This cuts off the electrical connection between the generator 11 and the LIB 15. Next, the control unit 40 executes power generation control for the generator 11 to suppress the amount of power generation (step S204).

Note that, although FIG. 6 shows an example in which the process of step S204 is executed after the processes of step S202 and step S203, this is not limiting. That is, for example, the control unit 40 may execute the processes of step S202 and step S203 after the process of step S204, or may execute the processes of step S202 and step S203 and the process of step S204 simultaneously.

When it is determined that the switch unit 17 of the first relay 16 is not stuck off (step S201, No), i.e., when the switch unit 19 of the second relay 18 is stuck off, the control unit 40 turns on all of the switch units 17 of the first relay 16 (step S205) and turns off all of the switch units 19 of the second relay 18 (step S206). This electrically connects the generator 11 and the lead battery 12, while cutting off the electrical connection between the generator 11 and the LIB 15.

In the above-mentioned Figures 5 and 6, after a stuck-on or stuck-off state is detected, it is determined whether the first relay 16 or the second relay 18 is stuck, but this is for the sake of convenience and is not limited to this. That is, for example, the control unit 40 may individually detect the stuck-on and stuck-off state of the switch unit 17 of the first relay 16 and the stuck-on and stuck-off state of the switch unit 19 of the second relay 18, and execute control of the switch unit 17 and the generator 11 according to the detected stuck state.

As described above, in the embodiment, the power supply system 1 includes a lead battery 12 (an example of a first battery), a LIB 15 (an example of a second battery), and a generator 11 connected in parallel. A first relay 16 is interposed between the lead battery 12 and the generator 11. A second relay 18 is interposed between the LIB 15 and the generator 11. The first relay 16 and the second relay 18 each include a plurality of switch units 17, 19 connected in parallel. The control device 30 of the power supply system 1 configured in this manner includes a detection unit 41, a switch control unit 42, and a power generation control unit 43. The detection unit 41 detects the on-fixation in the plurality of switch units 17, 19. When the detection unit 41 detects the on-fixation, the switch control unit 42 turns on all of the plurality of switch units 17, 19 that are connected in parallel to at least the switch unit 17, 19 in which the on-fixation is detected. The power generation control unit 43 controls the generator 11 according to the position of the switch unit 17, 19 that is detected as stuck on among the multiple switch units 17, 19. This makes it possible to prevent current from concentrating on the switch units 17, 19 that constitute the first and second relays 16, 18 when the first relay 16 or the second relay 18 is stuck.

The first battery is a lead battery 12, and the second battery is a LIB 15. This makes it possible to prevent current from concentrating in the switch sections 17 and 19 of the first and second relays 16 and 18, for example, if the first relay 16 connected to the lead battery 12 or the second relay 18 connected to the LIB 15 becomes stuck.

In the above embodiment, the control device 30 detects whether the switches 17, 19 are stuck on or off, and controls the switches 17, 19 according to the detected stuck state, but this is not limited to the above. That is, for example, a device on the battery pack 10 side (e.g., the monitoring device 20) may have a sticking detection function (detection unit 41) and a control function (switch control unit 42) for the switches 17, 19 according to the detected stuck state. In other words, the device on the battery pack 10 side (the monitoring device 20) may be configured to have some or all of the functions of the control device 30.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

1 Power supply system 11 Generator 12 Lead battery (first battery)
15 LIB (Second battery)
16 First relay 17, 19 Switch section 18 Second relay 30 Control device 41 Detection section 42 Switch control section 43 Power generation control section

Claims (6)

a first battery, a second battery, and a generator are connected in parallel, a first relay is interposed between the first battery and the generator, and a second relay is interposed between the second battery and the generator;
A control device for a power supply system, wherein the first relay and the second relay each include a plurality of switch units connected in parallel,
a detection unit that detects whether the plurality of switches are stuck on;
a switch control unit that turns on, when the stuck-on state is detected by the detection unit, all of the plurality of switch units that are connected in parallel to at least the switch unit in which the stuck-on state has been detected; and
a power generation control unit that controls the generator in accordance with a position of the switch unit in which a stuck-on state is detected among the plurality of switch units ,
The power generation control unit is
When the detection unit detects that the switch unit included in the second relay is stuck on, power generation control is executed on the generator so that a voltage of the second battery is higher than a voltage of the first battery.
A power supply system control device comprising : The power generation control unit is
2. The control device for a power supply system according to claim 1, wherein, when the detection unit detects that the switch unit included in the second relay is stuck on, power generation control is executed for the generator to suppress an amount of power generation. The power generation control unit is
3. The control device for a power supply system according to claim 1, further comprising: a power generation control unit configured to control a power generation amount of the generator when the detection unit detects that the switch unit included in the first relay is stuck on. The detection unit is
Detecting a stuck-off state in the plurality of switches;
The switch control unit is
when the detection unit detects that the relay is stuck off, turning on all of the plurality of switch units included in the first relay and turning off all of the plurality of switch units included in the second relay;
The power generation control unit is
When the detection unit detects that the switch unit included in the first relay is stuck off, power generation control is executed to suppress the amount of power generation of the generator.
4. The control device for a power supply system according to claim 1, the first battery is a lead battery,
5. The control device for a power supply system according to claim 1 , wherein the second battery is a lithium ion battery. a first battery, a second battery, and a generator are connected in parallel, a first relay is interposed between the first battery and the generator, and a second relay is interposed between the second battery and the generator;
A control method for a power supply system in which the first relay and the second relay are each configured to include a plurality of switch units connected in parallel, comprising:
a detection step of detecting a stuck-on state in the plurality of switch units;
a switch control step of turning on, when a stuck-on state is detected by the detection step, all of the switch units connected in parallel to at least the switch unit in which the stuck-on state has been detected, among the plurality of switch units;
a power generation control step of controlling the generator in accordance with a position of the switch unit in which a stuck-on state is detected among the plurality of switch units,
The power generation control step includes:
When the switch unit included in the second relay is detected as being stuck on in the detection step, power generation control is executed for the generator so that a voltage of the second battery is higher than a voltage of the first battery.
A method for controlling a power supply system comprising :

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