JP6375977B2 - Power supply - Google Patents

Description

  The present invention relates to a power supply device that is mounted on a vehicle or the like and outputs a voltage supplied from a battery by stepping up and down.

  There is a power supply system described in Patent Document 1 that includes a main battery and an auxiliary battery, and transmits and receives electric power between the main battery and the auxiliary battery via a DCDC converter.

  In the power supply system described in Patent Document 1, the control power supply that supplies power to the control circuit that controls the DCDC converter supplies power to the control circuit by stepping down the power supplied from the auxiliary battery. Yes.

JP 2006-94690 A

  In the power supply system described in Patent Document 1, since power is supplied from the auxiliary battery to the control power supply, power can be supplied from the auxiliary battery to the control power supply when the capacity of the auxiliary battery decreases. Disappear. In this case, since power is not supplied from the control power supply to the control circuit, the switching element of the power conversion circuit cannot be driven. As a result, power cannot be supplied from the main battery to the auxiliary battery.

  The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide a power supply device that can transfer power between batteries even when the capacity of any of a plurality of batteries decreases. It is to provide.

  The present invention is a power supply device applied to a power supply system including a main battery and an auxiliary battery having a lower rated voltage than the main battery, and is connected between the main battery and the auxiliary battery, A function of stepping down power supplied from the main battery and supplying it to the auxiliary battery side; and a function of stepping up electric power supplied from the auxiliary battery and supplying it to the main battery side by a switching element. A power conversion circuit that performs the step-down and step-up, a control circuit that controls the switching element of the power conversion circuit, and a high-voltage side control that steps down a voltage supplied from the main battery and supplies power to the control circuit And a low-voltage side control power source for stepping down a voltage supplied from the auxiliary battery and supplying power to the control circuit.

  With the above configuration, when the power supply from the high-voltage control power supply cannot be supplied to the control circuit, such as when the capacity of the main battery is reduced, the power can be supplied from the low-voltage control power supply to the control circuit. Therefore, electric power can be supplied from the auxiliary battery to the main battery side via the power conversion circuit.

  On the other hand, even when the power supply from the low-voltage control power supply cannot be supplied to the control circuit, such as when the capacity of the auxiliary battery is reduced, the power can be supplied from the high-voltage control power supply to the control circuit. Therefore, electric power can be supplied from the main battery to the auxiliary battery side via the power conversion circuit.

1 is a circuit diagram of a power supply system according to a first embodiment. The electric path in the case of supplying electric power from the main battery to the auxiliary machine battery side in 1st Embodiment is shown. The electric path in the case of supplying electric power from the auxiliary battery to the main battery in the first embodiment is shown. It is a circuit diagram of the power supply system concerning a 2nd embodiment. The electric path in the case of supplying electric power from the main battery to the auxiliary machine battery side in 2nd Embodiment is shown. The electric path in the case of supplying electric power from the auxiliary machine battery to the main battery side in 2nd Embodiment is shown.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, in each embodiment, the part which is mutually the same or equivalent is attached | subjected the same code | symbol in a figure, and uses the description for the part of the same code | symbol.

<First Embodiment>
A circuit diagram of the power supply system according to the present embodiment is shown in FIG. The power supply system according to the present embodiment is mounted on a vehicle, and a high-voltage circuit provided with a main battery 10 and a low-voltage circuit provided with an auxiliary battery 11 are connected to a DCDC converter that is a power supply device. 12 is used to transfer power between the high voltage circuit and the low voltage circuit.

  The main battery 10 is a lithium ion battery in which a plurality of battery cells are connected in series. The rated voltage of the main battery 10 is 288V, for example. The auxiliary battery 11 is a lead battery, and the rated voltage is, for example, 12V. Note that the types and rated voltages of the main battery 10 and the auxiliary battery 11 are not limited to these, and it is sufficient that the rated voltage of the main battery 10 is higher than the rated voltage of the auxiliary battery 11. Further, the maximum capacity of the main battery 10 is designed to be relatively larger than the maximum capacity of the auxiliary battery 11.

  The high voltage circuit provided with the main battery 10 is provided with a high voltage load 13, and the main battery 10 and the high voltage load 13 are connected via a system main relay 14. Examples of the high-voltage load 13 include a power control unit that supplies electric power to a motor that drives a vehicle. The system main relay 14 connects and disconnects the main battery 10 and the high voltage load 13. When the vehicle is stopped, the main battery 10 and the high voltage load 13 are disconnected by the system main relay 14. .

  The low voltage circuit 15 provided with the auxiliary battery 11 is provided with a low voltage load 15. Examples of the low-pressure load 15 include various lighting devices and electronic devices such as an ECU, a navigation device, an audio, and an anti-theft device. In order to continue supplying power to the built-in memory, dark current needs to flow to these electronic devices.

  The DCDC converter 12 includes a power conversion circuit 20, a driver 21, a high-voltage control power supply 22, and a low-voltage control power supply 23. The power conversion circuit 20 is a well-known circuit including a switching element such as an IGBT, and has a function of stepping down power supplied from the main battery 10 and supplying it to the low voltage circuit, and is supplied from the auxiliary battery 11. It has a function of boosting power and supplying it to a high voltage circuit. The driver 21 is a control circuit including a microcomputer, and transmits a control signal to the switching element of the power conversion circuit 20. In the power conversion circuit 20, the switching element is opened / closed by the control signal transmitted from the driver 21, and the supplied power is stepped up or stepped down and output. Electric power is supplied to the driver 21 from one of the high-voltage side control power supply 22 and the low-voltage side control power supply 23.

  The high voltage side control power supply 22 has a function of stepping down the power supplied from the main battery 10 and supplying it to the driver 21. On the other hand, the low-voltage side control power source 23 has a function of stepping down the power supplied from the auxiliary battery 11 and supplying it to the driver 21. Both the high-voltage side control power source 22 and the low-voltage side control power source 23 are provided with a transformer, and are constant voltage power sources that step down input power to, for example, 5V.

  When power is exchanged through the power conversion circuit 20, the capacities of the main battery 10 and the auxiliary battery 11 are monitored, and power is exchanged on the condition that one capacity falls below a predetermined value. Just start. Further, the required power of the high-voltage load 13 and the low-voltage load 15 may be monitored, respectively, and when the required power exceeds a predetermined value, power transfer may be started. These monitoring operations are performed if the driver 21, the high-voltage side control power source 22, and the low-voltage side control power source 23 acquire detection values of voltage sensors and current sensors provided in various places of the power supply system, and are performed based on the detection values. Good.

  FIG. 2 shows an electrical path when the capacity of the auxiliary battery 11 is reduced while the vehicle is stopped, and power supply from the auxiliary battery 11 to the low voltage load 15 becomes impossible. In this case, the electric power supplied from the auxiliary battery 11 is insufficient for starting the ECU, and the vehicle cannot be started.

  Therefore, the high-voltage side control power supply 22 steps down the power supplied from the main battery 10 and supplies it to the driver 21 based on the driver's operation on the main switch. The power conversion circuit 20 is driven by the control signal transmitted from the driver 21, and steps down the power supplied from the main battery 10 and supplies it to the auxiliary battery 11 and the low-voltage load 15. Thereby, ECU which is the low voltage | pressure load 15 can be started.

  At this time, the system main relay 14 is turned off to give priority to the auxiliary charging to the auxiliary battery 11 and the supply of electric power to the low voltage load 15. This is because, when the vehicle is started and power generation by the engine is started, it is possible to supply power to the main battery 10 and the auxiliary battery 11, and thereby supply power to the high voltage load 13. It is. Therefore, the system main relay 14 is turned on after the vehicle is started.

  On the other hand, FIG. 3 shows an electrical path when the capacity of the high-voltage battery is reduced and power supply from the main battery 10 to the high-voltage load 13 becomes impossible.

  Since the high voltage side control power supply 22 detects a decrease in the capacity of the main battery 10, the supply of power to the driver 21 is stopped. On the other hand, the low-voltage control power supply 23 steps down the power supplied from the auxiliary battery 11 and supplies it to the driver 21. The power conversion circuit 20 is driven by the control signal transmitted from the driver 21, and steps down the power supplied from the main battery 10 and supplies it to the auxiliary battery 11 and the low-voltage load 15.

  Incidentally, the low-pressure load 15 includes electronic devices such as an ECU, a navigation device, an audio, and an anti-theft device. A dark current needs to flow to these electronic devices in order to continue supplying power to the built-in memory. At this time, generally, dark current is supplied from the auxiliary battery 11 to the low-voltage load 15. However, the auxiliary battery 11 has a relatively small maximum capacity with respect to the main battery 10, and the capacity decreases due to the supply of dark current, and the deterioration proceeds.

  Therefore, in the present embodiment, the high-voltage side control power supply 22 supplies power to the driver 21 when the main switch of the vehicle is turned off, and the dark voltage from the main battery 10 via the power conversion circuit 20 is supplied. Start supplying current. The electric path for supplying the dark current is the same as the electric path shown in FIG.

  With the above configuration, the power supply system according to the present embodiment has the following effects.

  When the capacity of the auxiliary battery 11 is reduced, the power supplied from the main battery 10 is stepped down by the high-voltage control power supply 22 and the power conversion circuit 20 is driven by the power supplied from the high-voltage control power supply 22 doing. Therefore, when the capacity of the auxiliary battery 11 is reduced, it is possible to avoid a situation in which the power conversion circuit 20 cannot be driven. In addition, by supplying the power supplied from the main battery 10 to the low voltage circuit side via the power conversion circuit 20, the auxiliary battery 11 can be supplemented and the low voltage load 15 can be activated.

  When the capacity of the main battery 10 is reduced, the power supplied from the auxiliary battery 11 is stepped down by the low-voltage side control power source 23 and the power conversion circuit 20 is driven by the power supplied from the low-voltage side control power source 23 doing. Therefore, when the capacity | capacitance of the main battery 10 falls, the situation where the drive of the power converter circuit 20 becomes impossible can be avoided. In addition, by supplying power supplied from the auxiliary battery 11 to the high voltage circuit side via the power conversion circuit 20, it is possible to perform auxiliary charging to the main battery 10.

  The dark current is supplied to the low-voltage load 15 by the power of the main battery 10 having a large maximum capacity relative to the auxiliary battery 11. For this reason, the auxiliary battery 11 does not cause a decrease in capacity due to supply of dark current, and can suppress deterioration due to a decrease in capacity.

Second Embodiment
FIG. 4 shows a circuit diagram of the power supply system according to this embodiment. The power supply system according to the present embodiment is mounted on the vehicle of the first embodiment, and the high voltage circuit provided with the main battery 10 and the low voltage circuit provided with the auxiliary battery 11 are a power supply device. Are connected via the first DCDC converter 16, and exchange power between the high voltage circuit and the low voltage circuit.

  The high voltage circuit provided with the main battery 10 is provided with a high voltage load 13, and the main battery 10 and the high voltage load 13 are connected via a system main relay 14.

  In addition, the high voltage circuit and the low voltage circuit are connected via a second DCDC converter 17 which is a power supply device. The second DCDC converter 17 is connected to the high-voltage load 13 side with respect to the system main relay 14.

  The first DCDC converter 16 includes a first power conversion circuit 24, a first driver 25, and a high-voltage control power supply 26. The first power conversion circuit 24 is a well-known circuit including a switching element such as an IGBT, and has a function of stepping down the power supplied from the main battery 10 and supplying it to the low voltage circuit, and the supply from the auxiliary battery 11. A function of boosting the electric power to be supplied to the high voltage circuit. The first driver 25 is a control circuit including a microcomputer, and transmits a control signal to the switching element of the first power conversion circuit 24. In the first power conversion circuit 24, the switching element is opened and closed by the control signal transmitted from the first driver 25, and the supplied power is boosted or lowered to be output. Electric power is supplied to the first driver 25 from the high-voltage control power supply 26.

  The second DCDC converter 17 includes a second power conversion circuit 27, a second driver 28, and a low-voltage side control power supply 29.

  The second power conversion circuit 27 is a well-known circuit including a switching element such as an IGBT, and has only a function of boosting the power supplied from the auxiliary battery 11 and supplying the boosted power to the high voltage circuit. The second driver 28 is a control circuit including a microcomputer, and transmits a control signal to the switching element of the second power conversion circuit 27. In the second power conversion circuit 27, the switching element is opened / closed by the control signal transmitted from the second driver 28, and the supplied power is boosted or lowered to be output. Electric power is supplied to the second driver 28 from the low-voltage control power supply 29.

  Note that the high-voltage side control power source 26 and the low-voltage side control power source 29 in the present embodiment are substantially the same as the high-voltage side control power source 22 and the low-voltage side control power source 23 in the first embodiment, and thus description thereof is omitted. To do.

  Next, an electrical path in the case where power is transferred using either the first DCDC converter 16 or the second DCDC converter 17 will be described with reference to FIGS. 5 and 6.

  FIG. 5 shows an electrical path when the capacity of the auxiliary battery 11 is reduced and power supply from the auxiliary battery 11 to the low voltage load 15 becomes impossible. In this case, the electric power supplied from the auxiliary battery 11 is insufficient to activate the ECU which is the low-voltage load 15, and the vehicle cannot be activated.

  Therefore, the high-voltage control power supply 26 steps down the power supplied from the main battery 10 and supplies it to the first driver 25 based on the operation of the main switch from the driver. The first power conversion circuit 24 is driven by the control signal transmitted from the first driver 25 to step down the power supplied from the main battery 10 and supply it to the auxiliary battery 11 and the low voltage load 15. Thereby, ECU which is the low voltage | pressure load 15 can be started. At this time, as in the first embodiment, the system main relay 14 is turned off in order to give priority to the auxiliary charging to the auxiliary battery 11 and the supply of electric power to the low voltage load 15.

  FIG. 6 shows an electrical path when the capacity of the main battery 10 is reduced and power supply from the main battery 10 to the high voltage load 13 becomes impossible.

  The low-voltage side control power supply 29 steps down the power supplied from the auxiliary battery 11 and supplies it to the second driver 28. The second power conversion circuit 27 is driven by the control signal transmitted from the second driver 28 and boosts and outputs the power supplied from the auxiliary battery 11. In this case, power may be supplied to the main battery 10 and the high voltage load 13 after the system main relay 14 is turned on, or power is supplied only to the high voltage load 13 without turning on the system main relay 14. It is good also as what supplies.

  In the present embodiment, as in the first embodiment, dark current is supplied from the main battery 10 to the low-voltage load 15 via the first DCDC converter 16 when the vehicle is not started. The electrical path in this case is the same as that shown in FIG.

With the above configuration, the power supply system according to the present embodiment has an effect similar to the effect exhibited by the power supply system according to the first embodiment.
<Modification>
In the second embodiment, the first power conversion circuit 24 is capable of bi-directional power transfer, but is not limited to this, and has at least a function to step down the power supplied from the main battery 10. Just do it.

  In the second embodiment, the second power conversion circuit 27 has only the function of boosting the power supplied from the auxiliary battery 11, but this is not restrictive and bidirectional power transfer is possible. It may be good.

  -In 2nd Embodiment, although the 2nd DCDC converter 17 is provided in the high voltage | pressure load 13 side rather than the system main relay 14, it is good also as what is provided in the main battery 10 side rather than the system main relay 14. FIG.

  In the second embodiment, the first DCDC converter 16 and the second DCDC converter 17 are provided. However, the number of DCDC converters is not limited to this, and three or more DCDC converters may be provided.

  In each of the above embodiments, the main battery 10 and the auxiliary battery 11 are provided. However, the number of batteries is not limited to this, and three or more batteries may be provided. In this case, a DCDC converter may be provided so that power can be exchanged between the batteries.

  In the above embodiment, the power supply system is mounted on the vehicle. However, the mounting target is not limited to the vehicle, and can be mounted on a moving body other than the vehicle. can do.

  DESCRIPTION OF SYMBOLS 10 ... Main battery, 11 ... Auxiliary battery, 20 ... Power conversion circuit, 21 ... Driver, 22 ... High voltage side control power supply, 23 ... Low voltage side control power supply, 24 ... First power conversion circuit, 25 ... First driver, 26 ... high voltage side control power supply, 27 ... second power conversion circuit, 28 ... second driver, 29 ... low voltage side control power supply.

Claims (6)

A power supply device (12) applied to a power supply system comprising a main battery (10) and an auxiliary battery (11) having a lower rated voltage than the main battery,
Connected between the main battery and the auxiliary battery, and a function of stepping down the electric power supplied from the main battery and supplying the electric power to the auxiliary battery side, and increasing the electric power supplied from the auxiliary battery A power conversion circuit (20) having a function of supplying to the main battery side and performing the step-down and step-up by a switching element;
A control circuit (21) for controlling the switching element of the power conversion circuit;
A high-voltage side control power supply (22) for stepping down the voltage supplied from the main battery and supplying power to the control circuit;
A low-voltage side control power supply (23) that steps down the voltage supplied from the auxiliary battery and supplies power to the control circuit,
When the capacity of the main battery becomes smaller than a predetermined value,
Wherein the power supply from the low voltage-side control power source to the control circuit, and the power conversion circuit, and supplying power to the main battery side from the auxiliary battery, power supply. When the capacity of the auxiliary battery becomes smaller than a predetermined value,
The power is supplied from high-voltage-side control power source to the control circuit, and the power conversion circuit, and supplying power from the main battery to the auxiliary battery side power supply of claim 1 apparatus. A power supply device (12) applied to a power supply system comprising a main battery (10) and an auxiliary battery (11) having a lower rated voltage than the main battery,
Connected between the main battery and the auxiliary battery, and a function of stepping down the electric power supplied from the main battery and supplying the electric power to the auxiliary battery side, and increasing the electric power supplied from the auxiliary battery A power conversion circuit (20) having a function of supplying to the main battery side and performing the step-down and step-up by a switching element;
A control circuit (21) for controlling the switching element of the power conversion circuit;
A high-voltage side control power supply (22) for stepping down the voltage supplied from the main battery and supplying power to the control circuit;
A low-voltage side control power supply (23) that steps down the voltage supplied from the auxiliary battery and supplies power to the control circuit,
When the capacity of the auxiliary battery becomes smaller than a predetermined value,
The power is supplied from high-voltage-side control power source to the control circuit, and the power conversion circuit, and supplying power from the main battery to the auxiliary battery side power supply. The main battery has a larger maximum capacity and rated voltage than the auxiliary battery,
A load (15) connected to the auxiliary battery;
When supplying dark current to the load, power is supplied from the high-voltage control power supply to the control circuit, and the power conversion circuit steps down the power supplied from the main battery to reduce the dark current. The power supply device according to claim 1, wherein a current is supplied. A power supply device (12) applied to a power supply system comprising a main battery (10) and an auxiliary battery (11) having a lower rated voltage than the main battery,
Connected between the main battery and the auxiliary battery, and a function of stepping down the electric power supplied from the main battery and supplying the electric power to the auxiliary battery side, and increasing the electric power supplied from the auxiliary battery A power conversion circuit (20) having a function of supplying to the main battery side and performing the step-down and step-up by a switching element;
A control circuit (21) for controlling the switching element of the power conversion circuit;
A high-voltage side control power supply (22) for stepping down the voltage supplied from the main battery and supplying power to the control circuit;
A low-voltage side control power supply (23) that steps down the voltage supplied from the auxiliary battery and supplies power to the control circuit,
The main battery has a larger maximum capacity and rated voltage than the auxiliary battery,
A load (15) connected to the auxiliary battery;
When supplying dark current to the load, power is supplied from the high-voltage control power supply to the control circuit, and the power conversion circuit steps down the power supplied from the main battery to reduce the dark current. and supplying a current, power supply. As a circuit constituting the power conversion circuit,
A first power conversion connected between the main battery and the auxiliary battery, having a function of stepping down the electric power supplied from the main battery and supplying the electric power to the auxiliary battery side, and performing the step-down by a switching element A circuit (24);
Second power conversion connected between the main battery and the auxiliary battery, having a function of boosting the power supplied from the auxiliary battery and supplying the boosted power to the main battery side, and performing the boosting by a switching element A circuit (27),
As a circuit constituting the control circuit, a first control circuit (25) that controls the switching element of the first power conversion circuit and a second control circuit (28) that controls the switching element of the second power conversion circuit. ) And
The high-voltage side control power supply is configured to supply power to the first control circuit, and the low-voltage side control power supply is configured to supply power to the second control circuit. The power supply device according to any one of claims 1 to 5.

Images