JP2023047162A - Vehicle power source device - Google Patents

Abstract

To provide a vehicle power source device capable of achieving both switchover between serial connection and parallel connection to a power source during charging and discharging operation and reception and supply of electric power between power sources while a vehicle is stopped.SOLUTION: A vehicle power source device 30 comprises: a first electric storage device 31 and a second electric storage device 32; a first switch SW1 connected to a low voltage side of the first electric storage device and a high voltage side of the second electric storage device; a second switch SW2 connected to a high voltage side of the first electric storage device and between a low voltage side of the second electric storage device and the first switch; a third switch SW3 connected in between the low voltage side of the second electric storage device, the low voltage side of the first electric storage device and the first switch; and a DC-DC converter 18 which has first terminals H1 and L1 connected to both edges of the first electric storage device and second terminals H2 and L2 connected to both edges of the second electric storage device.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle power supply device.

Japanese Unexamined Patent Application Publication No. 2002-200002 describes a vehicle power supply device capable of switching the connection state of the power supply. In this vehicle power supply device, a first power storage device connected between a first node and a second node, a first switch connected between the second node and a third node, and a third node. a second power storage device connected between the fourth node, a second switch connected between the first node and the third node, and a DC-DC converter connected to the second node. The DC-DC converter changes the potential of the second node by allowing the second node to be connected to the third node or the fourth node. The resulting output power is supplied to the motor. When the load on the motor is small and the drive voltage required by the motor is small, the first switch is opened and the second switch is closed to connect the first power storage device and the second power storage device in parallel to the motor. do. On the other hand, when the load on the motor is large and the drive voltage required by the motor is large, the first switch is closed and the second switch is opened to connect the first power storage device and the second power storage device in series with the motor. connect to.

JP 2012-152079 A

In the vehicle power supply device of Patent Document 1, the connection of the first power storage device and the second power storage device to the electric motor is switched between parallel connection and series connection according to the magnitude of the load on the electric motor while power supply to the electric motor is maintained. can be switched with Further, by operating the DC-DC converter only when switching the connection between the first power storage device and the second power storage device, an increase in switching loss can be suppressed. However, the vehicle power supply device of Patent Document 1 is not configured to receive power between the first power storage device and the second power storage device while the vehicle is stopped.

In view of the above, it is an object of the present invention to provide a vehicle power supply device capable of switching between series/parallel connection of power sources during charging and discharging and receiving power between power sources while the vehicle is stopped.

The present invention provides a first power storage device and a second power storage device, a first switch connected to a low potential side of the first power storage device, a high potential side of the second power storage device, and a power storage device of the first power storage device. a second switch connected between a high potential side, a low potential side of the second power storage device and the first switch; a low potential side of the second power storage device; and a low potential of the first power storage device. a third switch connected between the side and the first switch; first terminals connected to both ends of the first power storage device; second terminals connected to both ends of the second power storage device; and a DC-DC converter comprising:

According to the vehicle power supply device described above, the first power storage device and the second power storage device can be connected in parallel by setting the first switch to the disconnected state and the second switch and the third switch to the connected state. By connecting the first switch and disconnecting the second switch and the third switch, the first power storage device and the second power storage device can be connected in series. In switching between series/parallel connection, safe switching can be realized even during charging/discharging by shutting off all switches. The DC-DC converter also has first terminals connected to both ends of the first power storage device and second terminals connected to both ends of the second power storage device. By operating the DC-DC converter with the first power storage device and the second power storage device connected in parallel, it is possible to suppress the inrush current from flowing between the first power storage device and the second power storage device, thereby ensuring safety. switching can be achieved. Furthermore, while the vehicle is stopped, by operating the DC-DC converter with the first power storage device and the second power storage device connected in parallel, electric power is received between the first power storage device and the second power storage device. can be made By receiving this electric power, it is possible to obtain effects such as raising the temperature of each power source while the vehicle is stopped and improving the efficiency of the power source. That is, according to the vehicle power supply device described above, it is possible to provide a vehicle power supply device capable of switching between series/parallel connection of power sources during charging and discharging and receiving power between power sources while the vehicle is stopped.

1 is a diagram showing an in-vehicle system including a vehicle power supply device according to a first embodiment; FIG. The figure which shows the switching control which connects each battery in series. FIG. 4 is a diagram showing switching control in the course of switching each battery from series connection to parallel connection; The figure which shows the switching control which connects each battery in parallel. FIG. 4 is a diagram showing switching control in the course of switching each battery from parallel connection to series connection; 4 is a flowchart of voltage difference control between the first node and the third node executed for the DC-DC converter; 7 is an example of a time chart when the voltage difference control shown in FIG. 6 is executed; 4 is a flowchart of temperature increase control for each battery executed for the DC-DC converter; 9 is an example of a time chart when the boost control shown in FIG. 8 is executed; The figure which shows the vehicle-mounted system containing the vehicle power supply device which concerns on 2nd Embodiment. The figure which shows the vehicle-mounted system containing the vehicle power supply device which concerns on 3rd Embodiment.

(First embodiment)
As shown in FIG. 1 , an in-vehicle system 1 is mounted on a vehicle and includes a circuit device 10 and a control device 13 . The circuit device 10 includes a drive inverter (M-INV) 15 that drives and controls a motor (M) 14, a power generation inverter (G-INV) 17 that controls power generation of a generator (G) 16, and a power supply device 30. and relays 19-22. It should be noted that the electric motor 14 and the generator 16 are examples of a rotating electric machine.

The M-INV15 and the G-INV17 are connected in parallel, and power can be supplied from the G-INV17 to the M-INV15. M-INV 15 and G-INV 17 are connected to power supply 30 via relays 19 and 20 . The power supply device 30 can be connected to the external power feeder 11 via the relays 21 and 22 .

The relays 19 and 21 are provided on the high potential wiring of the circuit device 10 . The relays 20 and 22 are provided on the low potential wiring of the circuit device 10 . Relays 19 and 20 are SMR relays and relays 21 and 22 are DC relays.

The power supply device 30 is a vehicle power supply device, and includes a first battery (BT1) 31, a second battery (BT2) 32, a first switch SW1, a second switch SW2, a third switch SW3, and a DC- A DC converter 18, a first voltage detection device 33, and a second voltage detection device 34 are provided. The first battery 31 and the second battery 32 are secondary batteries, more specifically, for example, lithium ion storage batteries with an output voltage of about several hundred volts, and a series connection of a plurality of cells (single batteries). It is an assembled battery comprising

The DC-DC converter 18 has first terminals H1, L1 and second terminals H2, L2. The first terminals H<b>1 and L<b>1 are connected to both ends of the first battery 31 . More specifically, the first terminal H1 is a first high potential terminal connected to the high potential side of the first battery 31 . The first terminal L1 is a first low potential terminal connected to the low potential side of the first battery 31 . The second terminals H2 and L2 are connected across the second battery 32 . More specifically, the second terminal H2 is a second high potential terminal connected to the high potential side of the second battery 32 . The second terminal L2 is a second low potential terminal connected to the low potential side of the second battery 32 . The DC-DC converter 18 can mutually convert power input or output from the first terminals H1, L1 and power input or output from the second terminals H2, L2.

The power supply device 30 can charge the first battery 31 and the second battery 32 with electric power supplied from the external power feeder 11 . The power supply device 30 can supply the power charged in the first battery 31 and the second battery 32 to the M-INV 15 as driving power for the electric motor 14 . Also, the power supply device 30 can charge the first battery 31 and the second battery 32 with the power generated by the generator 16 via the G-INV 17 .

The power supply device 30 includes a first node n1, a second node n2, a third node n3, and a fourth node n4. The first node n1 is a connection point between the high potential side of the first battery 31, the second switch SW2, and the first terminal H1. The second node n2 is a connection point between the low potential side of the first battery 31, the first switch SW1, the third switch SW3, and the first terminal L1. The third node n3 is a connection point between the high potential side of the second battery 32, the first switch SW1, the second switch SW2, and the second terminal H2. A fourth node n4 is a connection point between the low potential side of the second battery 32, the third switch SW3, and the second terminal L2. The power supply device 30 is connected to the high potential wiring of the circuit device 10 at the first node n1, and is connected to the low potential wiring of the circuit device 10 at the fourth node n4.

The first switch SW1 is connected to the low potential side of the first battery 31 at the second node n2, and is connected to the high potential side of the second battery 32 at the third node n3. The first switch SW1 is an RC-IGBT in which an IGBT and a free wheel diode are connected in anti-parallel, and is connected so that the direction of the current from the third node n3 to the second node n2 is forward. In other words, the forward direction of the first switch SW1 is the direction of current flowing from the high potential side of the second battery 32 to the low potential side of the first battery 31 . That is, the first switch SW1 is installed so that the conducting direction of its free wheel diode is the direction of the current flowing from the low potential side of the first battery 31 to the high potential side of the second battery 32 .

The second switch SW2 is connected to the high potential side of the first battery 31 at the first node n1, and is connected between the low potential side of the second battery 32 and the first switch SW1 at the third node n3. The second switch SW2 is an RC-IGBT in which an IGBT and a free wheel diode are connected in anti-parallel, and is connected so that the direction of the current from the first node n1 to the third node n3 is the forward direction. That is, the forward direction of the second switch SW2 is the direction of current flowing from the high potential side of the first battery 31 to between the high potential side of the second battery 32 and the first switch SW1. That is, the second switch SW2 is configured such that the direction of conduction of the freewheeling diode is the direction of the current flowing from between the low potential side of the second battery 32 and the first switch SW1 toward the high potential side of the first battery 31. is set up.

The third switch SW3 is connected between the low potential side of the first battery 31 and the first switch SW1 at the second node n2, and is connected to the low potential side of the second battery 32 at the fourth node n4. The third switch SW3 is an RC-IGBT in which an IGBT and a free wheel diode are connected in anti-parallel, and is connected so that the direction of the current from the second node n2 to the fourth node n4 is the forward direction. That is, the forward direction of the third switch SW3 is the direction of current flowing from between the low potential side of the first battery 31 and the first switch SW1 toward the low potential side of the second battery 32 . That is, the third switch SW3 is installed so that the conduction direction of the freewheeling diode is the direction of the current flowing from the low potential side of the second battery 32 to between the low potential side of the first battery 31 and the first switch SW1. It is

With the above circuit configuration, the power supply device 30 can switch the connection state of the first battery 31 and the second battery 32 between parallel connection and series connection by on/off control of the first to third switches SW1 to SW3. can be done.

A first terminal H1 of the DC-DC converter 18 is connected to the high potential side of the first battery 31 at the first node n1. The second terminal H2 is connected between the high potential side of the second battery 32 and the first switch SW1 at the third node n3. The first terminal H1 and the second terminal H2 are connected to the second switch SW2 at the first node n1 and the third node n3.

A first terminal L1 of the DC-DC converter 18 is connected between the low potential side of the first battery 31 and the first switch SW1 at the second node n2. The second terminal L2 is connected to the low potential side of the second battery 32 at the fourth node n4.

The first voltage detection device 33 is connected in parallel with the first battery 31 between the first node n1 and the second node n2, and can detect the voltage VB1 between the first node n1 and the second node n2. The second voltage detection device 34 is connected in parallel with the second battery 32 between the third node n3 and the fourth node n4, and can detect the voltage VB2 between the third node n3 and the fourth node n4.

The control device 13 includes a control section 40 and a detection section 50 . The control unit 40 includes a switch (SW) control unit 41 , a converter (CNV) control unit 42 , an inverter (INV) control unit 43 and a relay (RL) control unit 44 . The detection unit 50 includes a voltage detection unit 51 , a current detection unit 52 , a temperature detection unit 53 , a load detection unit 54 and a feed (CB) voltage detection unit 55 . The control device 13 is mounted in the vehicle as an ECU including, for example, a CPU, ROM, RAM, I/O, etc. The CPU implements each of these functions by executing programs installed in the ROM.

The SW control unit 41 performs ON/OFF control of the first switch SW1, the second switch SW2 and the third switch SW3. A CNV control unit 42 controls the DC-DC converter 18 . The INV control unit 43 performs on/off control of the semiconductor switching elements included in the M-INV15 and G-INV17. The RL control unit 44 performs ON/OFF control of the relays 19-22.

The voltage detection unit 51 acquires the voltage VB1 between the first node n1 and the second node n2 detected by the first voltage detection device 33, and obtains the voltage VB1 between the third node n3 and the second node n3 detected by the second voltage detection device 34. A voltage VB2 between the fourth node n4 is obtained. The current detection unit 52 acquires detected values or estimated values of the drive current of the electric motor 14 and the generated current of the generator 16 . The temperature detector 53 acquires the temperature of the external power feeder 11 . For example, the temperature of the external power feeder 11 detected by a temperature sensor provided in the external power feeder 11 is acquired. The load detector 54 acquires a detected value or an estimated value of the load of the electric motor 14 based on the drive current detected by the current detector 52, for example. The CB voltage detector 55 acquires the voltage of the external power feeder 11 . For example, the output voltage of the external power feeder 11 detected by a voltage sensor provided in the external power feeder 11 is acquired.

The SW control unit 41 switches the connection state between the first battery 31 and the second battery 32 between parallel connection and series connection by performing on/off control of the first switch SW1, the second switch SW2, and the third switch SW3. to switch. 2 to 4 show control when switching the connection state of the first battery 31 and the second battery 32 from series connection to parallel connection. 2 to 4 show control when switching the connection state of the first battery 31 and the second battery 32 from series connection to parallel connection. 4 and 5 show control when switching the connection state of the first battery 31 and the second battery 32 from parallel connection to series connection.

As shown in FIG. 2, when the first switch SW1 is controlled to be on and the second switch SW2 and the third switch SW3 are controlled to be off, the first battery 31 and the second battery 32 are connected in series. . During discharging of the batteries 31 and 32, a current Ia indicated by arrows in FIG. 2 flows. A current Ia is conducted through the IGBT.

FIG. 3 shows a state in which the first switch SW1 is turned off from the state in FIG. All of the first to third switches SW1 to SW3 are off, and currents Ib and Ic indicated by arrows in FIG. 3 flow. The current Ib flows through the freewheeling diode of the second switch SW2. The current Ic flows through the freewheeling diode of the third switch SW3. Even if all of them are in the OFF state, currents Ib and Ic flow through the freewheeling diodes in the second switch SW2 and the third switch SW3, so it is possible to suppress a momentary interruption of the discharge current.

FIG. 4 shows a state in which the second switch SW2 and the third switch SW3 are switched to the ON state from the state in FIG. The first switch SW1 is in an off state, and the second switch SW2 and the third switch SW3 are in an on state. In this state, the first battery 31 and the second battery 32 are connected in parallel, and currents Id and Ie indicated by arrows in FIG. 4 flow. The current Id is passed through the IGBT of the second switch SW2. The current Ie is passed through the IGBT of the third switch SW3.

Conversely, when switching from the state of parallel connection shown in FIG. 4 to the state of series connection shown in FIG. 2, the second switch SW2 and the third switch SW3 are first switched off as shown in FIG. to turn off all of the first to third switches SW1 to SW3. During discharging of the batteries 31 and 32, a current If indicated by arrows in FIG. 5 flows. The current If flows through the freewheeling diode of the second switch SW2. Even if all of them are in the OFF state, the current If flows through the freewheeling diode in the second switch SW2, so it is possible to suppress the momentary interruption of the discharge current. When the first switch SW1 is turned on from the state shown in FIG. 5, the series connection state shown in FIG. 2 can be obtained.

The SW control unit 41 controls the first to third switches SW1 to SW3 in the order shown in FIGS. do. When switching the connection state between the first battery 31 and the second battery 32 from parallel connection to series connection, the first to third switches SW1 to SW3 are controlled in the order shown in FIGS. Therefore, even if the connection state between the first battery 31 and the second battery 32 is switched during discharging, it is possible to suppress the momentary interruption of the discharge current.

The SW control unit 41 may be configured to switch the connection state between the first battery 31 and the second battery 32 based on various parameters acquired by the detection unit 50 as well. For example, the connection state is switched based on the detected load, which is the load of the electric motor 14 detected by the load detection unit 54, or the detected supply voltage, which is the load of the external power feeder 11 detected by the CB voltage detection unit 55. may be

Specifically, the SW control unit 41 connects the first battery 31 and the second battery 32 in series when the detected load is equal to or greater than a predetermined load threshold, and connects the first battery 31 and the second battery 32 in series when the detected load is smaller than the load threshold. , the first to third switches SW1 to SW3 may be configured to connect the first battery 31 and the second battery 32 in parallel. Further, the SW control unit 41 connects the first battery 31 and the second battery 32 in series when the detected power supply voltage exceeds a predetermined power supply voltage threshold, and connects the first battery 31 and the second battery 32 in series when the detected load is equal to or lower than the power supply voltage threshold. , the first to third switches SW1 to SW3 may be configured to connect the first battery 31 and the second battery 32 in parallel.

In this case, the load threshold is preferably set based on, for example, the depression amount of the accelerator pedal of the vehicle and the required driving force. Specifically, it is preferable to decrease the load threshold as the depression amount and the required driving force increase. The connection state of the first battery 31 and the second battery 32 can be appropriately switched according to the required driving force.

Moreover, it is preferable that the supply voltage threshold is, for example, the system voltage of the power supply device 30 when the first battery 31 and the second battery 32 are connected in parallel. Specifically, when the rated voltages of the first battery 31 and the second battery 32 are 400V, the system voltage during parallel connection is 400V. If the feed voltage threshold is set to 400V, it is possible to control the series connection when the detected feed voltage is 800V and the parallel connection when the detected feed voltage is 400V. The connection state of the first battery 31 and the second battery 32 can be appropriately switched according to the detected supply voltage and the load of the rotating electric machine.

By controlling the DC-DC converter 18, the converter control unit 42 controls the voltages of the first terminals H1 and L1 and the voltages of the second terminals H2 and L2. As shown in FIG. 4, when the first battery 31 and the second battery 32 are connected in parallel, the voltage between the first node n1 and the second node n2 is VB1, and the voltage between the third node n3 and the third node n3 is VB1. Assuming that the voltage between node n4 and node n4 is VB2, operating DC-DC converter 18 can reduce the difference between voltage VB1 and voltage VB2.

By reducing the absolute value of the voltage difference (VB1-VB2) between the voltages VB1 and VB2: Abs (VB1-VB2), the connection between the first battery 31 and the second battery 32 is switched from series connection to parallel connection. At this time, it is possible to suppress the inrush current from flowing between the first node n1 and the third node n3. Abs(VB1-VB2) corresponds to the voltage difference across the first switch SW1.

If voltage control is performed by always operating the DC-DC converter 18 during the parallel connection shown in FIG. Therefore, when the voltage difference Abs (VB1-VB2) across the first switch SW1 is larger than the predetermined operating voltage threshold value X1, the converter control unit 42 reduces the voltage difference Abs (VB1-VB2). to operate the DC-DC converter 18. Then, when the voltage difference Abs (VB1-VB2) is smaller than the predetermined stop voltage threshold value X2, the converter control unit 42 stops the DC-DC converter 18.

Note that the operating voltage threshold value X1 is a voltage value that, when a rush current flows between the first node n1 and the third node n3, does not affect the semiconductor switching elements forming each switch. is preferably set to a value obtained by simulation, experiment, or the like. Also, the stop voltage threshold X2 may be set to be equal to or less than the operating voltage threshold X1 (X2≦X1), and preferably smaller than the operating voltage threshold X1 (X2<X1).

FIG. 6 shows a flowchart of the voltage difference control process executed by the converter control section 42 for the DC-DC converter 18. As shown in FIG. The processing shown in FIG. 6 is repeatedly executed at predetermined intervals when switching the connection between the first battery 31 and the second battery 32 from series connection to parallel connection.

First, in step S101, the voltage VB1 detected by the first voltage detection device 33 and the voltage VB2 detected by the second voltage detection device 34 are obtained. After that, the process proceeds to step S102.

In step S102, it is determined whether or not the voltage difference Abs (VB1-VB2) exceeds the operating voltage threshold value X1. If Abs(VB1-VB2)>X1, the process proceeds to step S103, where the DC-DC converter 18 is turned on and operated, and then the process ends. If Abs(VB1-VB2).ltoreq.X1, the process proceeds to step S104.

In step S104, it is determined whether or not the voltage difference Abs (VB1-VB2) is less than the stop voltage threshold value X2. If Abs(VB1-VB2)<X2, the process proceeds to step S105, the DC-DC converter 18 is controlled to be turned off and stopped, and then the process ends. If Abs(VB1-VB2)≧X2, the process ends.

FIG. 7 shows a time chart of the voltage difference Abs (VB1-VB2) and the on/off state of converter control when the processing shown in FIG. 6 is executed. Note that the horizontal axis t indicates the time axis.

At time t0, the voltage difference is X2<Abs(VB1-VB2)≦X1, and the DC-DC converter 18 is controlled to be off. During the period from time t0 to just before t1, the voltage difference gradually increases, but since X2≤Abs(VB1-VB2)≤X1, negative determinations are made in steps S102 and S104 shown in FIG. Converter 18 is kept off.

At time t1, the voltage difference is Abs(VB1-VB2)>X1. Therefore, an affirmative determination is made in step S102, and the DC-DC converter 18 is switched from the OFF state to the ON state. As a result, the voltage difference gradually decreases during the period from time t1 to just before t2, but since X2≦Abs(VB1−VB2)≦X1, negative determinations are made in steps S102 and S104 shown in FIG. The DC-DC converter 18 is kept on.

At time t2, the voltage difference is Abs(VB1-VB2)<X2. Therefore, a negative determination is made in step S102, and an affirmative determination is made in step S104, and the DC-DC converter 18 is switched from the ON state to the OFF state.

Further, the converter control unit 42 may be configured to be able to detect temperature rise and deterioration of the first battery 31 and the second battery 32 by operating the DC-DC converter 18 while the vehicle is stopped. . Lithium ion storage batteries such as the first battery 31 and the second battery 32 may not be able to obtain sufficient output if the battery temperature is too low.

As shown in FIG. 4, when the first battery 31 and the second battery 32 are connected in parallel, the DC-DC converter 18 is operated to transfer electric power between the first battery 31 and the second battery 32. , the temperature of the first battery 31 and the second battery 32 can be raised. For example, when the temperature of the first battery 31 and the second battery 32 decreases while the vehicle is stopped, the DC-DC converter is configured to receive power between the first battery 31 and the second battery 32. 18, it is possible to prevent the temperature of the first battery 31 and the second battery 32 from dropping too much and not being able to obtain sufficient output.

Converter control unit 42 acquires the first temperature, which is the temperature of first battery 31 , and the second temperature, which is the temperature of second battery 32 , from temperature detection unit 53 . Then, when at least one of the first temperature and the second temperature is lower than a predetermined operating temperature threshold Y1, converter control unit 42 operates DC-DC converter 18 to Temperature increase control is performed to increase the temperatures of the first battery 31 and the second battery 32 by receiving electric power with the battery 32 . Then, when both the first temperature and the second temperature are higher than the predetermined stop temperature threshold value Y2, the temperature increase control by the DC-DC converter 18 is terminated.

The operating temperature threshold value Y1 is preferably set to a value determined by the output capability at low temperatures of the cells forming the assembled battery of each battery. Specifically, the stop temperature threshold Y2 may be set to be equal to or higher than the operating temperature threshold Y1 (Y2≧Y1), and is preferably set to be greater than the operating temperature threshold Y1 (Y2>Y1).

FIG. 8 shows a flowchart of the temperature increase control process executed by the converter control unit 42 for the DC-DC converter 18. As shown in FIG. The process shown in FIG. 8 is repeatedly performed at predetermined intervals in a state in which the first battery 31 and the second battery 32 are connected in parallel while the vehicle is stopped.

First, in step S201, the battery temperature Y is acquired. The battery temperature Y may be both the first temperature and the second temperature, or may be either one of them. After that, the process proceeds to step S202.

In step S202, it is determined whether the battery temperature Y is less than the operating temperature threshold value Y1. If Y<Y1, the process advances to step S203 to cause the DC-DC converter 18 to perform temperature increase control, and then the process ends. If Y≧Y1, the process proceeds to step S204.

In step S204, it is determined whether or not the battery temperature Y exceeds the stop temperature threshold value Y2. If Y>Y2, the process proceeds to step S205, and after stopping the temperature increase control of the DC-DC converter 18, the process ends. If Y.ltoreq.Y2, the process ends.

FIG. 9 shows the battery temperature Y, the ON/OFF state of the temperature increase control of the DC-DC converter 18, and the voltage difference between the first node n1 and the third node n3 when the process shown in FIG. 8 is executed. : (VB1-VB2) and a time chart of the current flowing between the first node n1 and the third node n3. Note that the horizontal axis t indicates the time axis.

At time t0, the battery temperature Y is Y>Y1, and the temperature increase control of the DC-DC converter 18 is turned off. The voltage difference is zero between the first node n1 and the third node n3, and the current is also zero. During the period from time t0 to just before t1, the battery temperature Y gradually decreases, but since Y≧Y1, negative determinations are made in steps S202 and S204 shown in FIG. is kept off.

At time t1, battery temperature Y<Y1. Therefore, an affirmative determination is made in step S202, and the temperature increase control of the DC-DC converter 18 is switched from the OFF state to the ON state. By turning on the temperature increase control of the DC-DC converter 18, the voltage difference between the first node n1 and the third node n3 is between -Vs and Vs during the period from time t1 to just before time t2. is controlled so that it changes periodically in a curve. As a result, the current flowing between the first node n1 and the third node n3 linearly and periodically changes between -Is and Is. Battery temperature Y gradually rises, but since Y1≦Y≦Y2, negative determinations are made in steps S202 and S204 shown in FIG.

At time t2, battery temperature Y becomes Y>Y2. Therefore, a negative determination is made in step S202 and an affirmative determination is made in step S204, and the temperature increase control of the DC-DC converter 18 is switched from the ON state to the OFF state.

(Second embodiment)
In the first embodiment, the circuit device 10 and the power supply device 30 in which the switches SW1 to SW3 are connected to any one of the nodes n1 to n4 have been exemplified and explained, but the present invention is not limited to this.

A circuit device 10a according to the second embodiment includes a power supply device 30a, as shown in FIG. In the power supply device 30a, the second switch SW2 is connected to the high potential side of the first battery 31 at the fifth node n5 connecting the relay 19 and the M-INV15 and G-INV17 instead of the first node n1. there is The third switch SW3 is connected to the low potential side of the second battery 32 at a sixth node n6 connecting the relay 20 and the M-INV15 and G-INV17 instead of the fourth node n4. Since other configurations are the same as those of the circuit device 10 according to FIG. 1, description thereof will be omitted.

(Third Embodiment)
A circuit device 10b according to the third embodiment includes a power supply device 30b, as shown in FIG. In the power supply device 30b, the second switch SW2 is connected to the high potential side of the first battery 31 at a seventh node n7 connecting the relay 21 and the external power feeder 11 instead of the first node n1. The third switch SW3 is connected to the low potential side of the second battery 32 at an eighth node n8 connecting the relay 22 and the external power feeder 11 instead of the fourth node n4. Since other configurations are the same as those of the circuit device 10 according to FIG. 1, description thereof will be omitted.

An in-vehicle system can be configured by combining the circuit devices 10a and 10b according to the second and third embodiments with the control device 13 shown in FIG. In the power supply devices 30a and 30b as well, the connection state between the first battery 31 and the second battery 32 can be switched between parallel connection and series connection according to the procedure described with reference to FIGS. 2 to 5 in the first embodiment. can be used, and similar effects can be obtained. Also, the control of the DC-DC converter 18 described with reference to FIGS. 6 to 9 can be executed, and the same effects can be obtained.

In each of the above-described embodiments, the switches SW1 to SW3 included in the power supply devices 30, 30a, and 30b are illustrated as semiconductor switching elements, but physical switches are used instead of the semiconductor switching elements. can also When semiconductor switching elements are used for the second switch SW2 and the third switch SW3, current flows through the free wheel diodes in the states shown in FIGS. is also preferred.

Further, in each of the above-described embodiments, the case where the power supply device has a circuit configuration included in the circuit devices 10, 10a, and 10, such as the power supply devices 30, 30a, and 30b, has been described as an example. The power supply may also include a control device such as the control device 13 shown. That is, a device including the power supply devices 30, 30a, 30b and each component included in the control device 13 may be used as the power supply device.

According to each of the above embodiments, the following effects can be obtained.

A vehicle power supply device 30 includes a first battery 31 as a first power storage device, a second battery 32 as a second power storage device, a first switch SW1, a second switch SW2, and a third switch SW3. and a DC-DC converter 18 . The first switch SW1 is connected to the low potential side of the first battery 31 and the high potential side of the second battery 32 . The second switch SW2 is connected between the high potential side of the first battery 31, the low potential side of the second battery 32, and the first switch. The third switch SW3 is connected between the low potential side of the second battery 32, the low potential side of the first battery 31, and the first switch. The DC-DC converter 18 has first terminals H1 and L1 connected to both ends of the first battery 31 and second terminals H2 and L2 connected to both ends of the second battery 32 .

A semiconductor switching element having a free wheel diode may be used for at least one of the first switch SW1, the second switch SW2, and the third switch SW3. In this case, the semiconductor switching element used as the first switch SW1 is installed so that the direction of current flowing from the high potential side of the second battery 32 to the low potential side of the first battery 31 is the forward direction. is preferred. The semiconductor switching element used as the second switch SW2 is configured such that the direction of the current flowing from the high potential side of the first battery 31 to between the low potential side of the second battery 32 and the first switch SW1 is the forward direction. preferably installed. The semiconductor switching element used as the third switch SW3 is configured such that the forward direction of the current flows from between the low potential side of the first battery 31 and the first switch SW1 toward the low potential side of the second battery 32. preferably installed. When the connection state of the first battery 31 and the second battery 32 is switched between parallel connection and series connection, a current flows through the freewheeling diode, thereby effectively suppressing a momentary interruption of the discharge current.

The power supply device may be configured to be connectable to an in-vehicle rotary electric machine (for example, the electric motor 14 or the generator 16) and the external power supply device 11, like the power supply devices 30, 30a, and 30b. In this case, the power supply device may further include each unit included in the control device 13 . For example, a load detection unit 54 that detects the load of the rotary electric machine as the detected load, a CB voltage detection unit 55 that detects the voltage of the external power supply machine 11 as the detected supply voltage, a first switch SW1, a second switch SW2, and A switch control unit 41 that controls the connection state of the third switch SW3, and a converter control unit 42 that controls the voltages of the first terminals H1 and L1 and the voltages of the second terminals H2 and L2 may be provided. .

In this case, when the detected load is equal to or higher than the predetermined load threshold, the switch control unit 41 switches the first switch SW1, the second switch SW2, and the switch SW1 so as to connect the first battery 31 and the second battery 32 in series. , the third switch SW3, and when the detected load is smaller than the load threshold, the first switch SW1, the second switch SW2, and the first switch SW1, the second switch SW2, and the first switch SW1, the second switch SW2, and the first battery 31 and the second battery 32 are connected in parallel. , the connection state of the third switch SW3. The connection state between the first battery 31 and the second battery 32 can be appropriately switched according to the detected load of the rotating electric machine.

Further, when the detected supply voltage exceeds a predetermined supply voltage threshold, the switch control unit 41 switches the first switch SW1, the second switch SW2, and the switch SW1 so as to connect the first battery 31 and the second battery 32 in series. , third switch SW3, and when the detected supply voltage is equal to or lower than the supply voltage threshold, the first switch SW1 and the second switch SW1 connect the first battery 31 and the second battery 32 in parallel. It may be configured to control the connection state of SW2 and the third switch SW3. The connection state between the first battery 31 and the second battery 32 can be appropriately switched according to the detected supply voltage.

Further, when the switch control unit 41 switches the connection between the first battery 31 and the second battery 32 from the series connection to the parallel connection, the converter control unit 42 causes the voltage difference between both ends of the first switch SW1 to reach a predetermined operating voltage. It may be configured to operate the DC-DC converter 18 to reduce the voltage difference when it is larger than the threshold X1. It is possible to prevent the semiconductor switching elements forming each switch from being damaged due to the inrush current flowing due to the voltage difference between both ends of the first switch SW1.

Further, when the switch control unit 41 switches the connection between the first battery 31 and the second battery 32 from the series connection to the parallel connection, the converter control unit 42 causes the voltage difference between both ends of the first switch SW1 to reach the predetermined stop voltage. It may be configured to stop the DC-DC converter 18 when it is smaller than the threshold value X2. It is possible to avoid a situation in which the DC-DC converter 18 is always operated during parallel connection and the power consumption is reduced due to the loss of the DC-DC converter 18 .

The power supply device may also include a temperature detection unit 53 that detects the temperature of the first battery 31 as the first temperature and detects the temperature of the second battery 32 as the second temperature. In this case, converter control unit 42 receives power between first battery 31 and second battery 32 when at least one of the first temperature and the second temperature is lower than predetermined operating temperature threshold value Y1. may be configured to operate the DC-DC converter 18 to It is possible to avoid the situation where the temperature of the first battery 31 and the second battery 32 is too low to obtain sufficient output while the vehicle is stopped.

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

DESCRIPTION OF SYMBOLS 18... DC-DC converter 30... Vehicle power supply device 31... First battery 32... Second battery H1, L1... First terminal H2, L2... Second terminal SW1 to SW3... First to second 3 switches

Claims (8)

a first power storage device (31) and a second power storage device (32);
a first switch (SW1) connected to the low potential side of the first power storage device and the high potential side of the second power storage device;
a second switch (SW2) connected between the high potential side of the first power storage device, the low potential side of the second power storage device, and the first switch;
a third switch (SW3) connected between the low potential side of the second power storage device, the low potential side of the first power storage device, and the first switch;
A DC-DC converter (18 ), and a power supply device for a vehicle (30). A semiconductor switching element comprising a free wheel diode is used for at least one of the first switch, the second switch, and the third switch,
The semiconductor switching element used as the first switch has a forward direction of current flowing from the high potential side of the second power storage device to the low potential side of the first power storage device,
In the semiconductor switching element used as the second switch, the direction of current flowing from the high potential side of the first power storage device to between the low potential side of the second power storage device and the first switch is the forward direction,
The forward direction of the semiconductor switching element used as the third switch is the current direction from between the low potential side of the first power storage device and the first switch toward the low potential side of the second power storage device. The vehicle power supply device according to claim 1 . It is connectable to an in-vehicle rotating electric machine (14, 16) and an external power feeder (11),
a load detection unit (54) that detects the load of the rotating electrical machine as a detected load;
a power supply voltage detection unit (55) for detecting the voltage of the external power supply as a detected power supply voltage;
a switch control unit (41) that controls connection states of the first switch, the second switch, and the third switch;
The vehicle power supply device according to claim 1 or 2, further comprising a converter control section (42) that controls the voltage of the first terminal and the voltage of the second terminal. It can be connected to an in-vehicle rotating electric machine,
a load detection unit that detects the load of the rotating electrical machine as a detected load;
a switch control unit that controls connection states of the first switch, the second switch, and the third switch;
The switch control unit
When the detected load is equal to or greater than a predetermined load threshold, the first switch, the second switch, and the third switch are connected so as to connect the first power storage device and the second power storage device in series. control the connection state,
a connection state of the first switch, the second switch, and the third switch such that the first power storage device and the second power storage device are connected in parallel when the detected load is smaller than the load threshold value; The vehicle power supply device according to any one of claims 1 to 3, which controls the It can be connected to an external power supply,
a power supply voltage detection unit that detects the voltage of the external power supply as a detected power supply voltage;
a switch control unit that controls connection states of the first switch, the second switch, and the third switch;
The switch control unit
the first switch, the second switch, and the third switch to connect the first power storage device and the second power storage device in series when the detected power supply voltage exceeds a predetermined power storage voltage threshold; control the connection state of the
When the detected power supply voltage is equal to or lower than the power supply voltage threshold, the first switch, the second switch, and the third switch connect the first power storage device and the second power storage device in parallel. 5. The vehicle power supply device according to claim 1, wherein the connection state of the vehicle is controlled. a switch control unit that controls connection states of the first switch, the second switch, and the third switch;
A converter control unit that controls the voltage of the first terminal and the voltage of the second terminal,
When the switch control unit switches the connection between the first power storage device and the second power storage device from a series connection to a parallel connection, the converter control unit is configured such that the voltage difference between both ends of the first switch is a predetermined operating voltage. 6. The vehicle power supply device according to claim 1, wherein the DC-DC converter is operated so as to reduce the voltage difference when the voltage difference is greater than a threshold value. a switch control unit that controls connection states of the first switch, the second switch, and the third switch;
A converter control unit that controls the voltage of the first terminal and the voltage of the second terminal,
When the switch control unit switches the connection between the first power storage device and the second power storage device from a series connection to a parallel connection, the converter control unit reduces the voltage difference between both ends of the first switch to a predetermined stop voltage. 7. The vehicle power supply device according to claim 1, wherein the DC-DC converter is stopped when the difference is smaller than a threshold value. a temperature detection unit that detects the temperature of the first power storage device as a first temperature and detects the temperature of the second power storage device as a second temperature;
A converter control unit that controls the voltage of the first terminal and the voltage of the second terminal,
The converter control unit receives power between the first power storage device and the second power storage device when at least one of the first temperature and the second temperature is lower than a predetermined operating temperature threshold. The vehicle power supply device according to any one of claims 1 to 7, wherein the DC-DC converter is operated so as to

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