JP7021661B2 - Power supply controller - Google Patents

Description

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

A power supply device that has two storage batteries and controls the discharge of the storage batteries by turning the switch on and off is known. For example, the power supply device of Patent Document 1 includes a first storage battery, a second storage battery, and an electric load. A first switch is provided on the first electric path connecting the first storage battery and the electric load, and a second switch is provided on the second electric path connecting the second storage battery and the electric load. There is. Then, based on the storage state of each storage battery, the first switch is turned on to supply power to the electric load from the first storage battery, and the second switch is turned on to supply power to the electric load from the second storage battery. Switching to the state is performed.

JP-A-2015-93554

By the way, when the electric load does not tolerate the power failure, the two switches are turned on after providing an overlapping period in which the two switches are temporarily turned on together so that the supply to the electric load is not interrupted. It is desirable that the state switch be switched. When the two switches are turned on together, a situation occurs in which the two storage batteries are connected via the first electric path and the second electric path. At this time, if there is a potential difference between the two storage batteries, a large current flows in the first electric path and the second electric path, and there is a possibility that the first switch and the second switch may malfunction.

The present invention has been made in view of the above problems, and a main object thereof is to provide a control device for a power supply device capable of appropriately switching a switch.

The first means is to connect the first storage battery (11) and the second storage battery (12), which are connected in parallel to the electric load (14, 15), and the first storage battery and the electric load, respectively. A first switch (SW1, SW3) provided in the path, a connection point on the electric load side of the first switch in the first electric path, and a second electric path connecting the second storage battery. It is applied to a power supply device including two switches (SW2 and SW4), and switches from a state in which one of the first switch and the second switch is turned on to a state in which the other is turned on when the electric load is energized. When the switch switching is performed, the control device (21) performs the switch switching after providing an overlapping period in which both of the switches are temporarily turned on, and the switch switching is performed. A determination unit for determining whether or not the potential difference between the first voltage, which is the voltage of the first storage battery, and the second voltage, which is the voltage of the second storage battery, is larger than a predetermined value, and the determination unit determines the potential difference. When it is determined that the value is smaller than the value, the switch switching is performed as the first control after the overlap period is provided, while the determination unit determines that the potential difference is larger than the predetermined value. Instead of the first control, a second control for suppressing energization between the storage batteries through the first switch and the second switch between the first storage battery and the second storage battery due to the potential difference is performed. It is equipped with a switch control unit.

In a dual power supply system in which a first storage battery and a second storage battery are connected in parallel with respect to an electric load, a switch is provided for each electric path in order to control whether one of the storage batteries supplies the electric load. Is provided. Then, the state in which the first switch is turned on and the electric power is supplied from the first storage battery to the electric load is switched between the state in which the second switch is turned on and the electric power is supplied from the second storage battery to the electric load.

When switching the switches, the first control provides an overlapping period in which both switches are temporarily turned on at the same time in order to suppress power failure. If the potential difference between the first storage battery and the second storage battery is large when both switches are temporarily turned on at the same time, a large current that causes each switch to fail may flow through the first switch and the second switch. There is.

Therefore, when the potential difference between the first voltage, which is the voltage of the first storage battery, and the second voltage, which is the voltage of the second storage battery, is larger than a predetermined value, the first switch and the second switch are replaced with the first control. The second control for suppressing the energization between the storage batteries is carried out. When the potential difference between the first voltage and the second voltage is large, it is possible to suppress the flow of a large current to the first switch and the second switch by performing the second control.

In the second means, when the determination unit determines that the potential difference is larger than the predetermined value, the switch control unit performs a process of prohibiting the switch switching as the second control.

When the determination unit determines that the potential difference is larger than the predetermined value, the switch switching of the first switch and the second switch is prohibited as the second control. That is, even when the switch is switched, if the determination unit determines that the potential difference is large, the switch is not switched and the state of each switch is maintained. As a result, when the potential difference is large, the switch is not switched and the first switch and the second switch are not turned on at the same time, thereby suppressing the flow of a large current to the first switch and the second switch. Can be done.

The third means includes a potential difference reduction processing unit that performs a potential difference reduction processing for reducing the potential difference when the determination unit determines that the potential difference is larger than a predetermined value.

When the determination unit determines that the potential difference is larger than the predetermined value and the switch switching is prohibited, the potential difference reduction process is performed so that the potential difference between the first voltage and the second voltage becomes smaller. As a result, the potential difference can be easily eliminated, and the switch switching prohibition period can be shortened.

The fourth means has a third switch (SW1, SW2) provided in parallel with the first switch (SW3) and the second switch (SW4), and is at least one of the first storage battery and the second storage battery. On the other hand, it is applied to the power supply device that discharges or charges a second electric load (14) different from the first electric load (15), which is the electric load, via the third switch. When the determination unit determines that the potential difference is larger than a predetermined value, the potential difference reduction processing unit turns on the third switch and switches to at least one of the first storage battery and the second storage battery. On the other hand, the potential difference is reduced by causing discharge or charging with the second electric load.

Discharge or charge is performed between at least one of the first storage battery and the second storage battery and the second electric load via the third switch. When the determination unit determines that the potential difference is larger than the predetermined value and the switch switching is prohibited, discharge or charge the battery between at least one of the first storage battery and the second storage battery and the second electric load. This reduces the potential difference. For example, when the first voltage is higher than the second voltage and the battery is discharged with respect to the second electric load, the third switch is controlled so that the battery is discharged from the first storage battery. When the first voltage is higher than the second voltage and the battery is charged from the second electric load, the third switch is controlled so that the second storage battery is charged. As a result, the potential difference can be easily eliminated, and the switch switching prohibition period can be shortened.

The fifth means is a third electric path connecting the first storage battery and the second storage battery, and in parallel with the first switch (SW3) and the second switch (SW4) in the third electric path. The power supply having the provided third switch (SW1, SW2) and having the third electric path as a large current path capable of energizing a current larger than that of the first electric path and the second electric path. When applied to the apparatus and the determination unit determines that the potential difference is larger than a predetermined value, the potential difference reduction processing unit turns on the third switch to turn on the third switch and the first storage battery and the first storage battery through the third electric path. The potential difference is reduced by conducting electricity between the second storage batteries.

The first storage battery and the second storage battery are connected by a third electric path, and the third electric path has a large current capable of passing a larger current than the first electric path and the second electric path. It is a current path. Therefore, even a large current due to the potential difference between the first storage battery and the second storage battery can be passed through the third current path. Therefore, when the determination unit determines that the potential difference is larger than the predetermined value and the switch switching is prohibited, the third switch is turned on to conduct conduction between the first storage battery and the second storage battery. As a result, a current flows from the storage battery on the high voltage side to the storage battery on the low voltage side via the third electric path, so that the potential difference can be easily eliminated and the switch switching prohibition period can be shortened.

The sixth means includes a rotary electric machine (14) connected to the third electric path to enable power running and power generation, and the rotary electric machine with respect to the first storage battery and the second storage battery by turning on / off the third switch. The third switch is turned on when the determination unit determines that the potential difference is larger than a predetermined value, which is applied to the power supply device capable of discharging or charging the battery. Then, the potential difference is reduced by conducting conduction between the first storage battery and the second storage battery through the third electric path.

The current due to charging and discharging between the rotary electric machine and the first storage battery and the second storage battery becomes a large current. Therefore, the third electric path needs to be a large current path capable of passing a larger current than the first electric path and the second electric path. By making the first storage battery and the second storage battery conductive by the third electric path, which is a large current path, the potential difference can be easily eliminated and the switch switching prohibition period can be shortened.

The seventh means is a third electric path connecting the first storage battery and the second storage battery, and in parallel with the first switch (SW3) and the second switch (SW4) in the third electric path. It has a third switch (SW1, SW2) provided, and the third electric path can be energized with a current larger than that of the first electric path and the second electric path, and the first electric path and the first electric path and the second electric path can be energized. The switch control unit is applied to the power supply device having a large current path having a path resistance lower than that of the second electric path, and the switch control unit determines that the potential difference is larger than the predetermined value by the determination unit. As two controls, the first switch, the second switch, and the third switch are turned on.

The third electric path is a large current path through which a larger current can flow than the first electric path and the second electric path. Further, in order to allow a large current to flow, the third electric path is formed of, for example, a bus bar or the like, and is configured to have a lower path resistance than the first electric path and the second electric path.

Therefore, when the determination unit determines that the potential difference is larger than the predetermined value, the first switch to the third switch are turned on. When all the switches are turned on, a current flows from the storage battery on the high voltage side to the storage battery on the low voltage side through the third electric path having a low path resistance. As a result, it is possible to suppress the flow of a large current to the first switch and the second switch.

The eighth means is that the first switch and the second switch are semiconductor switching elements (30) having a diode (31) connected in parallel, and the cathode of the diode is the first element on the storage battery side. (30A) and a second element (30B) whose diode cathode is on the electric load side are connected in series, and the switch control unit has the potential difference of the predetermined value by the determination unit. When it is determined to be larger, as the second control, of the first switch and the second switch, one of the switches connected to the storage battery on the high voltage side has the first element and the second element. Is turned on, and only the first element is turned on in the other switch connected to the storage battery on the low voltage side.

Each switch is configured by connecting a plurality of semiconductor switching elements in series. In each switch, the semiconductor switching element is connected so that the diodes connected in parallel to the semiconductor switching element are oriented in opposite directions in order to prevent dark current. Specifically, each switch has a first element in which the cathode of the diode parallel to the semiconductor switching element is on the storage battery side, and a second element in which the cathode of the diode is on the second load side.

When the determination unit determines that the potential difference is larger than the predetermined value, as the second control, the first element and the second switch of one of the first switch and the second switch connected to the storage battery on the high voltage side. The element is on and only the first element of the other switch connected to the storage battery on the low voltage side is on. That is, one switch connected to the storage battery on the high voltage side is in a state where current can flow in both directions, whereas the other switch connected to the storage battery on the low voltage side is electric from the storage battery. The current is flowing only on the load side. As a result, while the current flowing from each storage battery to the electric load can be suppressed, the current flowing from the storage battery on the high voltage side to the storage battery on the low voltage side can be suppressed. As a result, it is possible to suppress the flow of a large current to the first switch and the second switch.

Schematic configuration diagram of the power supply device according to the first embodiment Switch switching flowchart Flowchart for performing potential difference reduction processing in the switch switching prohibited state Flow chart for controlling switch switching in the second embodiment Flow chart for controlling switch switching in the third embodiment The figure which shows the current when the 2nd control is carried out Schematic block diagram of the power supply device in another embodiment Schematic block diagram of the power supply device in another embodiment

<First Embodiment>
Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings. In the present embodiment, in a vehicle traveling with an engine (internal combustion engine) as a drive source, it is embodied as an in-vehicle power supply device that supplies electric power to various devices of the vehicle. In each of the following embodiments, the parts that are the same or equal to each other are designated by the same reference numerals, and the description thereof will be used for the parts having the same reference numerals.

As shown in FIG. 1, the in-vehicle power supply device is a power supply device having a lead storage battery 11 and a lithium ion storage battery 12. From each of the storage batteries 11 and 12, power can be supplied to the starting device 13 for starting the engine, the rotary electric machine 14, and various electric loads 15 and 16. Further, each of the storage batteries 11 and 12 can be charged by the rotary electric machine 14. The lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the rotary electric machine 14, and the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the electric load 15. In the present embodiment, the lead storage battery 11 corresponds to the "first storage battery", the lithium ion storage battery 12 corresponds to the "second storage battery", the rotary electric machine 14 corresponds to the "second electric load", and the electric load 15 corresponds to the "second electric load". Corresponds to "first electric load".

The lead storage battery 11 is a well-known general-purpose storage battery. The lithium ion storage battery 12 is a high-density storage battery having a smaller power loss in charging / discharging, a higher output density, and a higher energy density than the lead storage battery 11. The lithium ion storage battery 12 is preferably a storage battery having higher energy efficiency during charging / discharging than the lead storage battery 11. Further, the lithium ion storage battery 12 is configured as an assembled battery each having a plurality of cell cells. The rated voltage of the lithium ion storage battery 12 is the same as that of the lead storage battery 11, for example, 12V.

The lithium ion storage battery 12 is housed in a storage case and is configured as a battery unit U integrated with a substrate. In FIG. 1, the battery unit U is shown surrounded by a broken line. The battery unit U has external terminals P1, P2, and P3, of which the lead-acid battery 11, the starting device 13, and the electric load 16 are connected to the external terminal P1 via wiring, and the external terminal P2 is connected to the external terminal P2 via wiring. The rotary electric machine 14 is connected to the external terminal P3, and the electric load 15 is connected to the external terminal P3 via wiring. The external terminal P1 is connected to the lead storage battery 11 via the fuse 17, and the external terminal P3 is connected to the electric load 15 via the fuse 18. The battery unit U and the lead storage battery 11 correspond to a "power supply device".

The rotary electric machine 14 is a generator with a motor function having a three-phase AC motor and an inverter as a power conversion device, and is configured as an ISG (Integrated Starter Generator) integrated with mechanical and electrical power. The rotary electric machine 14 has a power generation function of generating power (regenerative power generation) by rotating an engine output shaft or an axle, and a power running function of applying a rotational force to the engine output shaft. Due to the power running function of the rotary electric machine 14, it is possible to apply a rotational force to the engine when restarting the automatically stopped engine during idling stop. The rotary electric machine 14 supplies the generated power to the storage batteries 11 and 12 and the electric load 15.

The electric load 15 includes a constant voltage required load that requires that the voltage of the supplied power be constant. Here, the fact that the voltage of the supplied power is constant means that the power failure is not tolerated, and includes the fact that the voltage fluctuates within a predetermined range. Specific examples of the electric load 15 which is a constant voltage required load include various ECUs such as a navigation device, an audio device, and an engine ECU. In this case, by suppressing the voltage fluctuation of the supplied power, unnecessary resets and the like are suppressed in each of the above-mentioned devices, and stable operation can be realized. The electric load 15 may include a traveling system actuator such as an electric steering device or a brake device.

The electric load 16 is a general electric load other than the constant voltage required load. It can be said that the electric load 16 is a load to which a power failure is tolerated as compared with the electric load 16. Specific examples of the electric load 16 include a seat heater, a heater for a defroster of a rear window, a headlight, a wiper of a front window, a blower fan of an air conditioner, and the like.

Next, the battery unit U will be described. As an electric path in the battery unit U, an electric path L1 connecting the external terminals P1 and P2, that is, connecting the lead storage battery 11 and the rotary electric machine 14, is provided, and the switch SW1 is provided in the electric path L1. Further, as an electric path in the battery unit U, an electric path L2 connecting the connection point N1 on the electric path L1 and the lithium ion storage battery 12 is provided, and a switch SW2 is provided in the electric path L2. The connection point N1 is provided on the external terminal P2 side (rotary electric machine 14 side) of the switch SW1 in the electric path L1.

Further, in the battery unit U of the present embodiment, in addition to the electric paths L1 and L2, the connection point N2 (the point between the external terminal P1 and the switch SW1) on the electric path L1 and the external terminal P3 are connected. It has an electrical path L3. The electric path L3 is a path connecting the lead storage battery 11 and the electric load 15. A switch SW3 is provided in the electric path L3 (specifically, between the connection point N2- and the connection point N4).

Further, in the battery unit U, the connection point N3 of the electric path L2 (the point between the switch SW2 and the lithium ion storage battery 12) and the connection point N4 on the electric path L3 (the point between the switch SW3 and the external terminal P3) , Is provided with an electric path L4 for connecting the above. The electric path L4 is a path connecting the connection point N4 on the electric load 15 side of the switch SW3 in the electric path L3 and the lithium ion storage battery 12. A switch SW4 is provided in the electric path L4 (specifically, between the connection point N3 and the connection point N4).

The electric path L3 corresponds to the "first electric path", and the electric path L4 corresponds to the "second electric path". The switch SW3 corresponds to the "first switch", and the switch SW4 corresponds to the "second switch". The electric paths L1 and L2 correspond to the "third electric path", and the switches SW1 and SW2 correspond to the "third switch".

The electric paths L1 and L2 are connected to the rotary electric machine 14 and the storage batteries 11 and 12, and are large current paths through which a larger current flows than the electric paths L3 and L4. Specifically, the electric paths L1 and L2 allow a current of three times or more of the electric paths L3 and L4 to flow, and allow a current of 200 A or more to flow. Further, the electric paths L1 and L2 are formed of, for example, a bus bar or the like so that the path resistance thereof is low in order to allow a large current to flow. On the other hand, the electric paths L3 and L4 are formed of, for example, a copper pattern on a printed circuit board. Therefore, the electric paths L1 and L2 are configured to have a lower path resistance than the electric paths L3 and L4.

In each switch SW1 and SW2, a set of two semiconductor switching elements are arranged in parallel in order to cope with a large current. The semiconductor switching element is a MOSFET, and the parasitic diodes of the two sets of MOSFETs are connected in series so as to be opposite to each other.

Further, each switch SW3 and SW4 has a semiconductor switching element (PWM30) having a diode 31 (parasitic diode) connected in parallel. The diodes 31 of a pair of MOSFETs 30 of each switch SW3 and SW4 are connected in series so as to be opposite to each other. Specifically, in each switch SW3 and SW4, the first element 30A in which the cathode of the diode 31 is on the storage battery 11 and 12 side and the second element 30B in which the cathode of the diode 31 is on the electric load 15 side are connected in series. It is connected and configured. By configuring the diodes 31 to face each other in opposite directions in this way, for example, when the switch SW3 is turned off, the current flowing through the diode 31 is completely cut off.

As the semiconductor switching element used for each of the switches SW1 to SW4, it is also possible to use an IGBT, a bipolar transistor, or the like instead of the MOSFET. When an IGBT or a bipolar transistor is used, a diode instead of the diode 31 (parasitic diode) may be connected in parallel. Further, the switch element used for each of the switches SW1 to SW4 may be a mechanical switch instead of a semiconductor switching element.

The battery unit U includes a control device 21 that controls each of the switches SW1 to SW4. The control device 21 is composed of a microcomputer including a CPU, a ROM, a RAM, an input / output interface, and the like. The control device 21 controls the switches SW1 to SW4 and the like based on the storage state and the like of the storage batteries 11 and 12. For example, the control device 21 selectively uses the lead storage battery 11 and the lithium ion storage battery 12 to charge and discharge. Further, an ECU 22 which is a higher-level control device is connected to the control device 21. The control device 21 is connected to the ECU 22 or the like by a communication network such as CAN so that they can communicate with each other, and various data can be shared with each other.

Further, the battery unit U is provided with a voltage detector 23 for detecting the voltage of the external terminal P2 and a voltage detector 24 for detecting the voltage output from the lithium ion storage battery 12. The voltage detector 23 detects the voltage output from the lead storage battery 11 to the battery unit U, that is, the first voltage V1, which is the voltage of the lead storage battery 11. The voltage detector 24 detects the second voltage V2, which is the voltage of the lithium ion storage battery 12. The control device 21 acquires the voltage measured by each of the voltage detectors 23 and 24. The second voltage V2 may be calculated based on the SOC of the lithium ion storage battery 12 or the like, instead of being detected by the voltage detector 24.

The control device 21 controls to switch the switch to be turned on by the switches SW3 and SW4 based on the storage state of each of the storage batteries 11 and 12. Since the electric load 15 is a constant voltage required load, it is necessary to ensure that the power supply to the electric load 15 is not interrupted when the switches SW3 and SW4 are switched. Therefore, when performing switch switching for switching from a state in which one of the switch SW3 and the switch SW4 is turned on to a state in which the other is turned on, an overlapping period is provided in which both switches SW3 and SW4 are temporarily turned on. Then, the switch is switched. When both switches SW3 and SW4 are temporarily turned on at the same time, if the potential difference ΔV between the lead storage battery 11 and the lithium ion storage battery 12 is large, a large current that causes a problem in each switch SW3 and SW4 is generated in the switch SW3. And there is a risk of flowing to the switch SW4.

Therefore, when the switch is switched, it is determined whether the potential difference ΔV between the first voltage V1 and the second voltage V2 is larger than a predetermined value. Then, different control is performed depending on whether the potential difference ΔV is smaller than the predetermined value or the potential difference ΔV is larger than the predetermined value. Specifically, when the potential difference ΔV is smaller than a predetermined value, the first control is to switch from the state in which one is turned on to the state in which the other is turned on, after providing an overlapping period in which both are temporarily turned on. To carry out as. When the potential difference ΔV is larger than the predetermined value, the second control for suppressing the energization between the storage batteries 11 and 12 through the switch SW3 and the switch SW4 is performed instead of the first control. Specifically, as the second control, the switch switching of the switches SW3 and SW4 is prohibited, and the potential difference reduction process is executed.

The control when switching each switch SW3 and SW4 will be specifically described. FIG. 2 is a flowchart of switch switching. The process according to this flowchart is periodically executed by the control device 21.

In S11, it is determined whether or not the switch to be turned on can be switched among the switches SW3 and SW4. Specifically, it is determined whether the switches SW3 and SW4 can be switched based on the vehicle information. For example, when the engine is started by the starting device 13, when the engine is started by the rotary electric machine 14, and when the torque assist is performed by the rotary electric machine 14, sudden changes in voltage are likely to occur, and the switches SW3 and SW4 are not suitable for switching. Therefore, when the vehicle information such as the drive signal of the starting device 13 and the drive signal of the rotary electric machine 14 is acquired, it is determined that the switches SW3 and SW4 cannot be switched (S11: No), and the flowchart. Ends the processing of. On the other hand, when such vehicle information is not acquired, it is determined that the switches SW3 and SW4 can be switched (S11: Yes), and the process proceeds to S12.

In S11, instead of the control device 21 acquiring the vehicle information, the ECU 22 may acquire the vehicle information and notify the control device 21 whether or not the switches SW3 and SW4 can be switched based on the vehicle information. .. When the ECU 22 notifies that the switches SW3 and SW4 can be switched, it is determined that the switches SW3 and SW4 can be switched (S11: Yes), and the process proceeds to S12. When the ECU 22 notifies that the switches SW3 and SW4 cannot be switched, it is determined that the switches SW3 and SW4 cannot be switched (S11: No), and the processing of the flowchart is terminated.

In S12, it is determined whether or not the condition for switching the switch to be turned on by each of the switches SW3 and SW4 is satisfied based on the charging status of each of the storage batteries 11 and 12. When the switching condition is not satisfied (S12: No), that is, when switching of the switches SW3 and SW4 is unnecessary, the processing of the flowchart is terminated. If the switching condition is satisfied (S12: Yes), that is, if the switches SW3 and SW4 need to be switched, the process proceeds to S13.

In S13, the first voltage V1 detected by the voltage detector 23 is acquired. In S14, the second voltage V2 detected by the voltage detector 24 is acquired.

In S15, when the switch is switched, it is determined whether the potential difference ΔV between the first voltage V1 and the second voltage V2 is equal to or less than a predetermined value. The potential difference ΔV is an absolute value obtained by subtracting the second voltage V2 from the first voltage V1. The predetermined value is a value at which the current caused by the potential difference ΔV increases the possibility that the switches SW3 and SW4 will malfunction to some extent. The predetermined value is determined based on the path resistance of each electric path L3 and L4 and the minimum rated current of each electric path L3 and L4, and is, for example, 2V. Further, S15 corresponds to the "determination unit".

When it is determined in S15 that the potential difference ΔV is equal to or less than a predetermined value (S15: Yes), in S16, switch switching is performed as the first control. Specifically, from the state where one of the switches SW3 and SW4 is turned on, both are temporarily turned on together, and the other is turned on. For example, when switching from the switch SW3 to the switch SW4, the switch SW4 is turned on and the switch SW3 is turned off while the switch SW3 is on. That is, after providing an overlapping period in which both switches SW3 and SW4 are turned on, the switch to be turned on is switched from the switch SW3 to the switch SW4. Then, the processing of the flowchart is terminated. Note that S16 corresponds to the "switch control unit".

When it is determined in S15 that the potential difference ΔV is larger than the predetermined value (S15: No), in S17, the switch switching of the switch SW3 and the switch SW4 is prohibited as the second control. Even if the condition for switching the switches SW3 and SW4 is satisfied in S12, if it is determined in S15 that the potential difference ΔV is large, the switches SW3 and SW4 are not switched in S17. Holds the state of. For example, even when the condition for switching the switch to be turned on from the switch SW3 to the switch SW4 is satisfied, the on state of the switch SW3 and the off state of the switch SW4 are maintained until the potential difference ΔV becomes smaller than the predetermined value. .. Then, in S20, a potential difference reduction process for reducing the potential difference ΔV is executed. Note that S17 corresponds to the "switch control unit" and S20 corresponds to the "potential difference reduction processing unit".

The potential difference reduction process of S20 will be described with reference to FIG. FIG. 3 is a flowchart for carrying out the potential difference reduction process in a state where switch switching is prohibited. According to this S20, the potential difference ΔV is reduced by discharging or charging between at least one of the lead storage battery 11 and the lithium ion storage battery 12 and the rotary electric machine 14 via the switch SW1 and the switch SW2.

In S21, it is determined whether the rotary electric machine 14 is running power. Whether or not the rotary electric machine 14 is power running can be determined by acquiring the information of the rotary electric machine 14 from the ECU 22 or the like. When the rotary electric machine 14 is power running, the storage batteries 11 and 12 are discharged to the rotary electric machine 14.

In S21, when it is determined that the rotary electric machine 14 is power running (S21: Yes), in S22, it is determined whether the first voltage V1 is larger than the second voltage V2. When the first voltage V1 is larger (S22: Yes), in S23, the switch SW1 is turned on, the switch SW2 is turned off, and the process returns to FIG. 2 so that the lead-acid battery 11 is discharged. When the second voltage V2 is larger (S22: No), in S24, the switch SW2 is turned on, the switch SW1 is turned off, and the process returns to FIG. 2 so that the lithium ion storage battery 12 is discharged.

In S21, when it is determined that the rotary electric machine 14 is not power running (S21: No), in S25, it is determined whether the rotary electric machine 14 is generating power. Whether or not the rotary electric machine 14 is generating power can be determined by acquiring the information of the rotary electric machine 14 from the ECU 22 or the like. When the rotary electric machine 14 is generating power, the storage batteries 11 and 12 are charged from the rotary electric machine 14. When it is determined in S25 that the rotary electric machine 14 is not generating power (S25: No), the process returns to the process of FIG.

In S25, when it is determined that the rotary electric machine 14 is generating power (S25: Yes), in S26, it is determined whether the first voltage V1 is larger than the second voltage V2. When the first voltage V1 is larger (S26: Yes), in S27, the switch SW2 is turned on and the switch SW1 is turned off so that the lithium ion storage battery 12 is charged. return. When the second voltage V2 is larger (S26: No), in S28, the switch SW1 is turned on, the switch SW2 is turned off, and the process returns to FIG. 2 so that the lead-acid battery 11 is charged. ..

In this way, the switches SW1 and SW2 are controlled so that the storage battery on the high voltage side of the lead storage battery 11 and the lithium ion storage battery 12 is discharged and the storage battery is charged on the low voltage side. As a result, the potential difference ΔV between the lead storage battery 11 and the lithium ion storage battery 12 can be easily eliminated, and the switch switching prohibition period can be shortened.

Then, the process returns to the flowchart of FIG. When the potential difference reduction process of FIG. 3 is executed in S20, the process of the flowchart ends.

In the present embodiment, when it is determined that the potential difference ΔV is large when the switch is switched, the switch switching of the switch SW3 and the switch SW4 is prohibited. Then, while the switch switching is prohibited, the potential difference reduction process is performed so that the potential difference ΔV can be reduced. As a result, when the potential difference ΔV is large, it is possible to suppress the flow of a large current through the switch SW3 and the switch SW4. Further, by executing the potential difference reduction process, the potential difference ΔV can be easily eliminated, and the switch SW3 and the switch SW4 can be switched quickly.

As the potential difference reduction process of S20 in FIG. 2, instead of performing the process of the flowchart of FIG. 3, the switch SW1 and the switch SW2 are turned on, and the lead storage battery 11 and the lithium ion storage battery 12 pass through the electric path L1 and the electric path L2. The potential difference ΔV may be reduced by conducting electricity between them. The electric path L1 and the electric path L2 are large current paths capable of passing a large current as compared with the electric path L3 and the electric path L3. Therefore, even a large current due to the potential difference ΔV exceeding a predetermined value can be passed through the electric path L1 and the electric path L2.

Therefore, in S15, when it is determined that the potential difference ΔV is larger than the predetermined value, and in S17, when the switch switching is prohibited, the switch SW1 and the switch SW2 are turned on to move between the lead storage battery 11 and the lithium ion storage battery 12. Make it conductive. As a result, the current flows from the storage battery on the high voltage side to the storage battery on the low voltage side via the electric path L1 and the electric path L2, so that the potential difference ΔV can be easily eliminated and the switch switching prohibition period can be shortened.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

When switching the switches SW3 and SW4, the first control provides an overlapping period in which both switches SW3 and SW4 are temporarily turned on at the same time in order to suppress power failure. When both switches SW3 and SW4 are temporarily turned on at the same time, if the potential difference ΔV between the lead-acid battery 11 and the lithium-ion storage battery 12 is large, the switches SW3 and SW4 may fail in each switch SW3 and SW4. There is a risk that a large current will flow.

Therefore, when the potential difference ΔV between the first voltage V1 which is the voltage of the lead storage battery 11 and the second voltage V2 which is the voltage of the lithium ion storage battery 12 is larger than a predetermined value, the switch SW3 and the switch SW3 and The second control for suppressing the energization between the storage batteries 11 and 12 through the switch SW4 is performed. When the potential difference ΔV is large, it is possible to suppress the flow of a large current to the switch SW3 and the switch SW4 by performing the second control.

When the determination unit determines that the potential difference ΔV is larger than the predetermined value, the switch switching of the switch SW3 and the switch SW4 is prohibited as the second control. That is, even when the switch is switched, if the determination unit determines that the potential difference ΔV is large, the switch is not switched and the states of the switches SW3 and SW4 are maintained. As a result, in a state where the potential difference ΔV is large, in order to switch between the switch SW3 and the switch SW4, the switch SW3 and the switch SW4 are not turned on in duplicate, thereby suppressing a large current from flowing through the switch SW3 and the switch SW4. can do.

When the determination unit determines that the potential difference ΔV is larger than the predetermined value and the switch switching is prohibited, the potential difference reduction process is performed so that the potential difference ΔV becomes small. As a result, the potential difference ΔV can be easily eliminated, and the switch switching prohibition period can be shortened.

When it is determined by the determination unit that the potential difference ΔV is larger than the predetermined value and the switch switching is prohibited, at least one of the lead storage battery 11 and the lithium ion storage battery 12 and the rotary electric machine 14 are discharged or charged. This reduces the potential difference ΔV. For example, when the first voltage V1 is higher than the second voltage V2 and the rotary electric machine 14 is discharged, the switch SW1 is turned on so that the lead storage battery 11 discharges. When the first voltage V1 is higher than the second voltage V2 and is being charged from the rotary electric machine 14, the switch SW2 is turned on so that the lithium ion storage battery 12 is charged. As a result, the potential difference ΔV can be easily eliminated, and the switch switching prohibition period can be shortened.

If the determination unit determines that the potential difference ΔV is larger than the predetermined value and the switch switching is prohibited, the switches SW1 and SW2 are turned on to conduct conduction between the lead storage battery 11 and the lithium ion storage battery 12. It may be configured. As a result, the current flows from the storage battery on the high voltage side to the storage battery on the low voltage side via the electric paths L1 and L2, so that the potential difference ΔV can be easily eliminated and the switch switching prohibition period can be shortened.

Further, the current due to charging and discharging between the rotary electric machine 14, the lead storage battery 11 and the lithium ion storage battery 12 becomes a large current. Therefore, the electric path L1 and the electric path L2 need to be a large current path capable of passing a larger current than the electric path L3 and the electric path L4. By conducting the lead storage battery 11 and the lithium ion storage battery 12 through the electric path L1 and the electric path L2, which are large current paths, the potential difference ΔV can be easily eliminated and the switch switching prohibition period can be shortened.

<Second Embodiment>
In the second embodiment, when the determination unit determines that the potential difference ΔV is larger than a predetermined value, the switch SW1, the switch SW2, the switch SW3, and the switch SW4 are turned on as the second control. FIG. 4 is a flowchart of switch switching in the second embodiment. The process according to this flowchart is periodically executed by the control device 21. In FIG. 4, the processes of S11 to S16 are the same as the processes of S11 to S16 of FIG. 2, and therefore the description thereof will be omitted.

When it is determined in S15 that the potential difference ΔV is larger than the predetermined value (S15: No), in S30, all the switches SW1 to SW4 are turned on as the second control. The electric path L1 and the electric path L2 are large current paths capable of passing a large current as compared with the electric path L3 and the electric path L4. Further, in order to pass a large current, the path resistance is smaller than that of the electric path L3 and the electric path L4. Therefore, when all the switches SW1 to SW4 are turned on, a current due to the potential difference ΔV flows through the electric path L1 and the electric path L2 having a small path resistance, and a large current is suppressed from flowing through the electric path L3 and the electric path L4. can. Then, the processing of the flowchart is terminated. Note that S30 corresponds to the "switch control unit".

<Third Embodiment>
In the third embodiment, when the determination unit determines that the potential difference ΔV is larger than a predetermined value, as a second control, the second switch of the switch SW3 and the switch SW4 connected to the storage battery on the high voltage side is connected. The configuration is such that the 1st element 30A and the 2nd element 30B are turned on, and only the 1st element 30A of the other switch connected to the storage battery on the low voltage side is turned on. FIG. 5 is a flowchart of switch switching in the third embodiment. The process according to this flowchart is periodically executed by the control device 21. In FIG. 5, the processes of S11 to S16 are the same as the processes of S11 to S16 of FIG. 2, and therefore the description thereof will be omitted.

In S15, when it is determined that the potential difference ΔV is larger than the predetermined value (S15: No), in S41, it is determined whether the first voltage V1 is larger than the second voltage V2. When the first voltage V1 is larger than the second voltage V2 (S41: Yes), in S42, as the second control, the first element 30A and the second element 30B of the switch SW3 are turned on, and the first element 30A of the switch SW4 is turned on. Turn on. That is, in the switch SW3 connected to the lead storage battery 11 which is the storage battery on the high voltage side, both MOSFETs 30 are turned on. On the other hand, in the switch SW4 connected to the lithium ion storage battery 12 which is the storage battery on the low voltage side, only the first element 30A in which the cathode of the diode 31 faces the storage battery side is turned on. Then, the processing of the flowchart is terminated. Note that S42 corresponds to the "switch control unit".

When the first voltage V1 is smaller than the second voltage V2 (S41: No), in S43, as the second control, the first element 30A and the second element 30B of the switch SW4 are turned on, and the first element 30A of the switch SW3 is turned on. Turn on. That is, in the switch SW4 connected to the lithium ion storage battery 12 which is the storage battery on the high voltage side, both MOSFETs 30 are turned on. On the other hand, in the switch SW3 connected to the lead storage battery 11 which is the storage battery on the low voltage side, only the first element 30A in which the cathode of the diode 31 faces the storage battery side is turned on. Then, the processing of the flowchart is terminated. Note that S43 corresponds to the "switch control unit".

In the switch connected to the storage battery on the low voltage side, the current flow when only the first element 30A is turned on will be described with reference to FIG. FIG. 6 is a diagram showing a current when the second control is performed in the third embodiment. In FIG. 6, the alternate long and short dash line indicates the path through which the current flows. FIG. 6 shows a case where the first voltage V1 is larger than the second voltage V2, that is, the case where the processing of S42 of FIG. 5 is performed.

In S42 of FIG. 5, the control device 21 turns on the first element 30A and the second element 30B of the switch SW3 and turns on the first element 30A of the switch SW4 as the second control. In the switch SW3 connected to the lead storage battery 11 which is the storage battery on the high voltage side, both MOSFETs 30 are turned on, and a current can flow in both directions. Therefore, a current flows from the lead storage battery 11 to the electric load 15 side.

On the other hand, in the switch SW4 connected to the lithium ion storage battery 12 which is the storage battery on the low voltage side, only the first element 30A in which the cathode of the diode 31 faces the storage battery side is turned on, and the lithium ion storage battery 12 is turned on. Therefore, the current flows only to the electric load 15 side. Specifically, since the first element 30A is on, a current flows, while the second element 30B is off, so a current flows through the diode 31. ing. Therefore, depending on the orientation of the diode 31 of the second element 30B, a current flows from the lithium ion storage battery 12 to the connection point N4 (electric load 15) side, but no current flows from the connection point N4 to the lithium ion storage battery 12 side. Therefore, even if a current tries to flow from the lead storage battery 11 to the lithium ion storage battery 12 due to the potential difference ΔV, the current does not flow.

Similarly, in the case of S43, the switch SW4 connected to the lithium ion storage battery 12 on the high voltage side is in a state where a current can flow in both directions. In the switch SW3 connected to the lead storage battery 11 on the low voltage side, a current flows through the diode 31 in the second element 30B. Therefore, the current flows only from the lead storage battery 11 to the electric load 15 (connection point N4) side. Therefore, even if a current tries to flow from the lithium ion storage battery 12 to the lead storage battery 11 due to the potential difference ΔV, the current does not flow.

In the third embodiment, when the determination unit determines that the potential difference ΔV is larger than a predetermined value, the second control of the switch SW3 and the switch SW4 is one of the switches connected to the storage battery on the high voltage side. The 1st element 30A and the 2nd element 30B are turned on, and only the 1st element 30A of the other switch connected to the storage battery on the low voltage side is turned on. That is, one switch connected to the storage battery on the high voltage side is in a state where current can flow in both directions, whereas the other switch connected to the storage battery on the low voltage side is electric from the storage battery. The current is flowing only on the load side. As a result, while the current flowing from the storage batteries 11 and 12 to the electric load 15 can be passed, the current flowing from the storage battery on the high voltage side to the storage battery on the low voltage side can be suppressed. It is possible to suppress the flow of a large current due to the potential difference ΔV between the storage batteries 11 and 12.

<Other embodiments>
The present invention is not limited to the above embodiment, and may be implemented as follows, for example. Incidentally, the configuration of the following alternative example may be applied individually to the configuration of the above embodiment, or may be applied in any combination.

-Although the lithium ion storage battery 12 is used in the above embodiment, another high-density storage battery may be used. For example, a nickel-metal hydride battery may be used. In addition, it is also possible to use the same storage battery (for example, a lead storage battery, a lithium ion storage battery, etc.).

-The lithium ion storage battery 12 may be referred to as a "first storage battery", and the lead storage battery 11 may be referred to as a "second storage battery". In this case, the switch SW4 corresponds to the "first switch" and the switch SW3 corresponds to the "second switch".

The electric device connected to the external terminal P2 may be an electric load or the like that requires a constant voltage, instead of the rotary electric machine 14.

-It is also possible to embody the present invention by using the switch SW1 as the "first switch" and the switch SW2 as the "second switch". In this case, the electric path L1 corresponds to the "first electric path", the electric path L2 corresponds to the "second electric path", and the rotary electric machine 14 corresponds to the "electric load".

Specifically, in the switch SW1 and the switch SW2, when the potential difference ΔV is larger than a predetermined value, a state in which one of the switch SW1 and the switch SW2 is turned on and the other is turned on after providing an overlapping period. The first control for switching the switch to is not carried out, and another second control is carried out. In this case, it is desirable to carry out the control of the first embodiment or the third embodiment as the second control.

Further, the configuration of the present invention may be used for switch switching of switches SW1 and SW2 and switch switching of switches SW3 and SW4, respectively. In this case, it is desirable that the predetermined value used for determining the potential difference ΔV in the switch SW1 and the switch SW2 is larger than the predetermined value used for determining the potential difference ΔV in the switch SW3 and the switch SW4.

In the above embodiment, the present invention is used for a power supply device having four switches, but the present invention may be used for a power supply device having any combination of two switches, switch SW1 and switch SW2, or switch SW3 and switch SW4. .. In this case, it is desirable to carry out the control of the third embodiment as the second control.

-A power supply device that supplies power to a constant voltage required load without causing a power failure may be embodied as follows. As shown in FIG. 7, it is a power supply device including two switches SW3 and SW4, and each switch SW3 and SW4 may be configured to include one MOSFET 30. At this time, the cathode of the diode 31 faces the electric load 15 side (external terminal P2 side). In such a configuration, a current flows from the switch in the off state to the electric load 15 via the diode 31.

Further, as shown in FIG. 8, it is a power supply device provided with four electric paths L1 to L4, and switches SW1 and SW2 are provided in the two electric paths L1 and L2, respectively, and the two electric paths are provided. The diodes D1 and D2 may be provided in L3 and L4. The cathodes of the diodes D1 and D2 face the electric load 15 side (external terminal P3 side). In such a configuration, electric power can be supplied to the electric load 15 from the higher voltage of the lead storage battery 11 and the lithium ion storage battery 12.

The control unit (control device) and its method described in the present disclosure are provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be realized by a dedicated computer. Alternatively, the controls and methods thereof described in the present disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

11 ... Lead storage battery, 12 ... Lithium ion storage battery, 15 ... Electric load, 21 ... Control device, L3 ... Electric path, L4 ... Electric path, SW3 ... Switch, SW4 ... Switch, U ... Battery unit.

Claims (8)

The first storage battery (11) and the second storage battery (12), which are connected in parallel to the electric load (14, 15), respectively,
The first switch (SW1, SW3) provided in the first electric path connecting the first storage battery and the electric load, and
The second switch (SW2, SW4) provided in the second electric path connecting the connection point on the electric load side of the first electric path and the second storage battery in the first electric path.
When the switch is switched from the state in which one of the first switch and the second switch is turned on to the state in which the other is turned on when the electric load is energized. It is a control device (21) that performs the switch switching after providing an overlapping period in which both switches are temporarily turned on.
When the switch is switched, a determination unit for determining whether or not the potential difference between the first voltage, which is the voltage of the first storage battery, and the second voltage, which is the voltage of the second storage battery, is larger than a predetermined value. ,
When the determination unit determines that the potential difference is smaller than the predetermined value, the switch switching is performed as the first control after providing the overlap period, while the potential difference is smaller than the predetermined value by the determination unit. When it is determined that the voltage is too large, instead of the first control, the energization between the storage batteries through the first switch and the second switch between the first storage battery and the second storage battery due to the potential difference is performed. The switch control unit that executes the second control to suppress,
A control device for a power supply unit. The power supply device according to claim 1, wherein the switch control unit performs a process of prohibiting the switch switching as the second control when the determination unit determines that the potential difference is larger than the predetermined value. Control device. The control device for a power supply device according to claim 2, further comprising a potential difference reduction processing unit that performs a potential difference reduction processing for reducing the potential difference when the determination unit determines that the potential difference is larger than a predetermined value. It has a third switch (SW1, SW2) provided in parallel with the first switch (SW3) and the second switch (SW4).
For at least one of the first storage battery and the second storage battery, the electric load is a second electric load (14) different from the first electric load (15) via the third switch. It is applied to the power supply device that discharges or charges the battery.
When the determination unit determines that the potential difference is larger than a predetermined value, the potential difference reduction processing unit turns on the third switch with respect to at least one of the first storage battery and the second storage battery. The control device for a power supply device according to claim 3, wherein the potential difference is reduced by discharging or charging the battery with the second electric load. A third electric path connecting the first storage battery and the second storage battery, and a third switch provided in parallel with the first switch (SW3) and the second switch (SW4) in the third electric path. It is applied to the power supply device having (SW1, SW2) and having the third electric path as a large current path capable of energizing a current larger than that of the first electric path and the second electric path.
When the determination unit determines that the potential difference is larger than a predetermined value, the potential difference reduction processing unit turns on the third switch and between the first storage battery and the second storage battery through the third electric path. The control device for a power supply device according to claim 3, wherein the potential difference is reduced by conducting the current. A rotary electric machine (14) connected to the third electric path and capable of power running and power generation is provided, and by turning on / off the third switch, discharge between the first storage battery and the rotary electric machine with respect to the second storage battery or It is applied to the power supply device that enables charging,
When the determination unit determines that the potential difference is larger than a predetermined value, the potential difference reduction processing unit turns on the third switch and passes between the first storage battery and the second storage battery through the third electric path. The control device for a power supply device according to claim 5, wherein the potential difference is reduced by conducting the current. A third electric path connecting the first storage battery and the second storage battery, and a third switch provided in parallel with the first switch (SW3) and the second switch (SW4) in the third electric path. (SW1, SW2), the third electric path can be energized with a current larger than that of the first electric path and the second electric path, and can be energized from the first electric path and the second electric path. It is also applied to the power supply device with a large current path with low path resistance.
When the determination unit determines that the potential difference is larger than the predetermined value, the switch control unit turns on the first switch, the second switch, and the third switch as the second control. The control device for the power supply device according to claim 1. The first switch and the second switch are semiconductor switching elements (30) having a diode (31) connected in parallel, and the first element (30A) whose cathode of the diode is on the storage battery side and the said. The cathode of the diode is configured by connecting in series with the second element (30B) on the electric load side.
When the determination unit determines that the potential difference is larger than the predetermined value, the switch control unit is connected to the storage battery on the high voltage side of the first switch and the second switch as the second control. The power supply according to claim 1, wherein one of the switches turns on the first element and the second element, and the other switch connected to the storage battery on the low voltage side turns on only the first element. Device control device.

Images