JP2017099234A - Vehicle power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress extension of charging time.SOLUTION: A vehicle power supply device 10 comprises: an inlet 25 to which an external power supply 20 is connected when a high voltage battery 11 is charged using the external power supply 20; a main converter 33 which is provided between the high voltage battery 11 and low voltage battery 30 and supplies electric power from the high voltage battery 11 to the low voltage battery 30; a sub converter 34 which is provided between the inlet 25 and the low voltage battery 30 and supplies electric power from the inlet 25 to the low voltage battery 30; and a controller 42 which switches between a first supply mode in which electric power is supplied to the low voltage battery 30 through the main converter 33 and a second supply mode in which electric power is supplied to the low voltage battery 30 through the sub converter 34 during external charging in which the external power supply 20 is connected to the inlet 25. The controller 42 switches between the first supply mode and the second supply mode on the basis of the temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle power supply device including a first power storage unit and a second power storage unit.

  As electric vehicles that can be charged by an external power source, there are not only electric vehicles that include only a motor generator as a power source, but also hybrid electric vehicles that include a motor generator and an engine as a power source. These electric vehicles have a high voltage system including a high voltage battery for supplying electric power to the motor generator, and a low voltage system including a low voltage battery for supplying electric power to controllers and auxiliary machines. (See Patent Document 1). In addition, when a high voltage battery is charged by an external power supply, it is necessary to start a controller for charge control, so power is supplied from the high voltage system to the low voltage system via a power converter such as a converter. ing.

JP 2011-87408 A

  By the way, when the temperature of the power converter rises excessively when supplying power from the high voltage system to the low voltage system, it is necessary to stop the power converter from the viewpoint of protecting the power converter. Thus, stopping the power converter to cut off the power supply to the low voltage system is a factor that lowers the power supply voltage of the controller and a factor that stops the controller. Also, stopping the controller for charge control is a factor for stopping charging by an external power source, and a factor for extending the charging time of the high voltage battery.

  An object of the present invention is to suppress the extension of the charging time.

  The vehicle power supply device according to the present invention is a vehicle power supply device including a first power storage unit and a second power storage unit having a lower voltage than the first power storage unit, and is used when charging the first power storage unit using an external power source. A first power supply that is provided between the first power storage unit and the second power storage unit, and that supplies power from the first power storage unit to the second power storage unit. A converter, a second power converter provided between the power supply connection unit and the second power storage unit and supplying power from the power supply connection unit to the second power storage unit; and A first supply mode for supplying power to the second power storage unit via the first power converter and power to the second power storage unit via the second power converter during external charging to which a power source is connected A mode control unit that switches between the second supply mode and the mode control unit Switches between the second supply mode and the first supply mode based on temperature.

  According to the present invention, the mode control unit supplies power to the second power storage unit via the first power supply mode via the first power converter and the first supply mode for supplying power to the second power storage unit via the second power converter. The second supply mode is switched based on the temperature. Thereby, at the time of the external charging in which the external power supply is connected to the power supply connecting portion, the charging of the first power storage unit by the external power supply can be continued, and the extension of the charging time of the first power storage unit can be suppressed.

It is the schematic which shows the vehicle power supply device which is one embodiment of this invention. It is a flowchart which shows an example of the execution procedure of mode switching control. It is explanatory drawing which shows the electric power supply condition when the 1st supply mode is performed during external charging. It is explanatory drawing which shows the electric power supply condition when performing 2nd supply mode during external charging. It is the schematic which shows the structure of the vehicle power supply device which is other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a vehicle power supply device 10 according to an embodiment of the present invention. The illustrated vehicle power supply apparatus 10 is applied to an electric vehicle that can be charged by an external power supply. As such an electric vehicle, for example, there is an electric vehicle including only a motor generator as a power source, and there is a hybrid electric vehicle including a motor generator and an engine as power sources.

  As shown in FIG. 1, the vehicle power supply device 10 includes a high voltage battery (first power storage unit) 11. A high voltage system 13 that supplies power to the motor generator 12 is connected to the high voltage battery 11. The high voltage system 13 includes an inverter 15 connected to the high voltage battery 11 via an energization line 14 and a motor generator 12 connected to the inverter 15 via an energization line 16. Drive wheels 17 are connected to the motor generator 12 via a drive system (not shown). During vehicle acceleration in which the motor generator 12 is powered, the DC power is converted into AC power by the inverter 15, and power is supplied from the high voltage battery 11 to the motor generator 12. On the other hand, during vehicle deceleration for regenerating motor generator 12, AC power is converted into DC power by inverter 15, and power is supplied from motor generator 12 to high voltage battery 11.

  The high voltage battery 11 is connected to an external charging system 21 to which power is supplied from an external power source 20. The external charging system 21 includes a charger 23 connected to the high voltage battery 11 via the energization line 22, and an inlet (power supply connection unit) 25 connected to the charger 23 via the energization line 24. ing. When charging the high voltage battery 11 using the external power source 20, the connector 27 of the charging cable 26 is connected to the inlet 25, and the plug 28 of the charging cable 26 is connected to the outlet 29 of the external power source 20. As described above, when the external power source 20 is connected to the inlet 25, the AC power is converted into DC power by the charger 23, and power is supplied from the external power source 20 to the high voltage battery 11 through the charger 23. The charger 23 is a so-called AC-DC converter constituted by a plurality of switching elements and the like, and has a function of converting AC power into DC power.

  The vehicle power supply device 10 includes a low voltage system 32 including a low voltage battery (second power storage unit) 30 and a vehicle body load 31. The low voltage battery 30 is designed to have a lower voltage than the high voltage battery 11. The low voltage system 32 is connected to the high voltage system 13 through the main converter 33 and is connected to the external charging system 21 through the sub-converter 34. That is, the high voltage system 13 is connected to the input terminal of the main converter 33 via the energization line 35, and the low voltage system 32 is connected to the output terminal of the main converter 33 via the energization line 36. The external charging system 21 is connected to the input terminal of the sub-converter 34 via an energization line 37, and the low voltage system 32 is connected to the output terminal of the sub-converter 34 via an energization line 38.

  As described above, the main converter 33 as the first power converter is provided between the high voltage battery 11 constituting the high voltage system 13 and the low voltage battery 30 constituting the low voltage system 32. By operating the main converter 33, power is supplied from the high voltage battery 11 to the low voltage battery 30. Further, a sub-converter 34 as a second power converter is provided between the inlet 25 constituting the external charging system 21 and the low voltage battery 30 constituting the low voltage system 32. By operating the sub-converter 34, power is supplied from the inlet 25 to the low voltage battery 30.

  When the control system is activated by a switch operation or the like, power is supplied from the high voltage system 13 to the low voltage system 32 via the main converter 33 (first supply mode). Further, at the time of external charging in which the external power source 20 is connected to the inlet 25, power is supplied from the external charging system 21 to the low voltage system 32 via the sub-converter 34 (second supply mode). That is, when the external power source 20 is not connected to the inlet 25, the first supply mode for operating the main converter 33 is executed, while when the external power source 20 is connected to the inlet 25, the sub-converter is operated. A second supply mode that activates 34 is executed. Thus, by supplying power from the sub-converter 34 to the low voltage system 32 during external charging, power can be supplied to the low voltage system 32 without going through the high voltage battery 11, and energy efficiency during external charging can be achieved. Can be improved.

  The main converter 33 and the sub-converter 34 are so-called DC-DC converters configured by switching elements, reactors, and the like, and have a function of stepping down DC power and supplying it to the low voltage system 32. The charger 23 and the sub-converter 34 are housed in one case 40, and the charger 23 and the sub-converter 34 constitute one in-vehicle charging unit 41. As described above, by incorporating the charger 23 and the sub-converter 34 into one case 40, the sharing of the cooling system or the like can be achieved, and the number of parts can be reduced and the cost can be reduced.

  The vehicle power supply device 10 includes a controller 42 that controls the charger 23, the main converter 33, the sub-converter 34, and the like. As described above, at the time of external charging in which the external power supply 20 is connected to the inlet 25, the second supply mode for operating the sub-converter 34 and supplying power to the low voltage system 32 is executed. That is, the controller 42 not only controls the charger 23 to charge the high voltage battery 11, but also controls the sub-converter 34 to stabilize the power supply voltage applied to the vehicle body load 31 such as the controller 42. By the way, external charging is often continued for a long time, and operating the sub-converter 34 for a long time has caused an excessive temperature rise of the sub-converter 34.

  As described above, when the temperature of the sub-converter 34 rises excessively, it is necessary to stop the sub-converter 34 from the viewpoint of protecting the internal elements. In this case, since the power supply to the low voltage system 32 is cut off, there is a risk that the power supply voltage of the controller 42 and the like will decrease as the low voltage battery 30 is discharged. There is a risk that it will be. Further, in the illustrated vehicle power supply device 10, since both the charger 23 and the sub-converter 34 are incorporated in the in-vehicle charging unit 41, the heat of the sub-converter 34 increases the temperature of the charger 23. There is a fear. Such a temperature rise of the charger 23 is a factor that restricts the function of the charger 23, and is a factor that restricts or stops external charging.

  Therefore, the controller 42 executes mode switching control for switching the power supply path of the low voltage system 32 based on the outside air temperature or the like in order to maintain power supply to the low voltage system 32 during external charging. That is, the controller 42 operates the main converter 33 to supply power to the low voltage system 32 based on the outside air temperature and the like, and operates the sub-converter 34 to supply power to the low voltage system 32. The mode switching control for switching between the second supply mode to be performed is executed. As described above, the controller 42 functioning as the mode control unit includes an outside air temperature sensor 43 that detects the outside air temperature, a charger temperature sensor 44 that detects the temperature of the charger 23, and a main temperature sensor that detects the temperature of the main converter 33. 45, a sub-temperature sensor 46 for detecting the temperature of the sub-converter 34, and the like are connected. The controller 42 includes a microcomputer composed of a CPU, ROM, RAM, and the like, a drive circuit unit that generates a control current, and the like.

[Mode switching control]
Hereinafter, the mode switching control executed by the controller 42 will be described. Note that the mode switching control is executed with the connection of the external power supply 20 to the inlet 25. FIG. 2 is a flowchart showing an example of the procedure for executing the mode switching control. In FIG. 2, the temperature of the main converter 33 is described as “main temperature”, the temperature of the sub-converter 34 is described as “sub-temperature”, and the temperature of the charger 23 is described as “charger temperature”. In FIG. 2, “main” means the main converter 33, and “sub” means the sub-converter 34.

  As shown in FIG. 2, in step S10, it is determined whether or not the outside air temperature is equal to or higher than a predetermined temperature (first threshold value) T1. If it is determined in step S10 that the outside air temperature exceeds a predetermined temperature T1 (for example, 40 ° C.), that is, if it is estimated that the ambient temperature of the vehicle power supply device 10 is high, the process proceeds to step S11. The first supply mode for operating the converter 33 is executed. As described above, when the first supply mode is executed, the process proceeds to step S12, and it is determined whether or not the temperature of the main converter 33 is equal to or lower than a predetermined temperature (second threshold) T2. If it is determined in step S12 that the temperature of the main converter 33 is lower than the predetermined temperature T2, the temperature of the main converter 33 is within the normal range, so that the process proceeds to step S13 and the first operation for operating the main converter 33 is performed. The continuation of the supply mode is determined. On the other hand, if it is determined in step S12 that the temperature of the main converter 33 exceeds the predetermined temperature T2, the temperature of the main converter 33 exceeds the normal range, so that the process proceeds to step S14 and the second supply mode is changed from the first supply mode to the second supply mode. Switching to the supply mode is determined.

  On the other hand, if it is determined in step S10 that the outside air temperature is lower than the predetermined temperature T1, that is, if it is estimated that the ambient temperature of the vehicle power supply device 10 is normal temperature, the process proceeds to step S15, and the sub-converter 34 is turned on. The second supply mode to be activated is executed. As described above, when the second supply mode is executed, the process proceeds to step S16, and it is determined whether or not the temperature of the sub-converter 34 is equal to or lower than a predetermined temperature (third threshold value) T3. If it is determined in step S16 that the temperature of the sub-converter 34 is lower than the predetermined temperature T3, the process proceeds to step S17, and it is determined whether or not the temperature of the charger 23 is equal to or lower than the predetermined temperature (fourth threshold) T4. Is done. If it is determined in step S17 that the temperature of the charger 23 is lower than the predetermined temperature T4, the temperatures of the sub-converter 34 and the charger 23 are within the normal range. The continuation of the second supply mode using 34 is determined. On the other hand, if it is determined in step S16 that the temperature of the sub-converter 34 exceeds the predetermined temperature T3, or if it is determined in step S17 that the temperature of the charger 23 exceeds the predetermined temperature T4, the sub-converter 34 Alternatively, since the temperature of the charger 23 exceeds the normal range, the process proceeds to step S19, and switching from the second supply mode to the first supply mode is determined.

  In addition, even if it is a case where 1st supply mode or 2nd supply mode is performed through step S13, S14, S18, S19, it progresses to step S10 again and it is whether external temperature is more than predetermined temperature T1. Is determined. That is, even if the first supply mode is executed through steps S13 and S19, if it is determined in step S10 that the outside air temperature is lower than the predetermined temperature T1, the process proceeds to step S15. The first supply mode is switched to the second supply mode. Similarly, even if the second supply mode is executed through steps S14 and S18, if it is determined in subsequent step S10 that the outside air temperature is equal to or higher than the predetermined temperature T1, the process proceeds to step S11. The second supply mode is switched to the first supply mode.

  As described above, when the outside air temperature exceeds the predetermined temperature T1, that is, when the ambient temperature of the in-vehicle charging unit 41 is high, the first supply mode for operating the main converter 33 is executed. Here, FIG. 3 is an explanatory diagram showing a power supply state when the first supply mode is executed during external charging. The black arrows shown in FIG. 3 are arrows indicating the power supply status. As shown in FIG. 3, when the ambient temperature of the in-vehicle charging unit 41 is high, electric power is supplied from the main converter 33 to the low voltage system 32 by executing the first supply mode. Thereby, while maintaining the power supply to the low voltage system 32, the sub-converter 34 can be stopped to stop the heat generation, and the temperature increase of the in-vehicle charging unit 41, that is, the charger 23 can be suppressed. Thus, since the output restriction of the charger 23 can be avoided by suppressing the temperature rise of the charger 23, the charging of the high voltage battery 11 can be continued, and the charging time of the high voltage battery 11 can be continued. Can be shortened. Thereby, a user's convenience can be improved and the merchantability of an electric vehicle can be improved.

  On the other hand, when the outside air temperature is lower than the predetermined temperature T1, that is, when the ambient temperature of the in-vehicle charging unit 41 is low, the second supply mode for operating the sub-converter 34 is executed. Here, FIG. 4 is an explanatory diagram showing a power supply state when the second supply mode is executed during external charging. The black arrows shown in FIG. 4 are arrows indicating the power supply status. As shown in FIG. 4, when the ambient temperature of the in-vehicle charging unit 41 is low, power is supplied from the sub-converter 34 to the low voltage system 32 by executing the second supply mode. Thus, when the ambient temperature of the in-vehicle charging unit 41 is low, that is, when it is difficult for the charger 23 to excessively rise in temperature, the sub-converter 34 is actively operated by executing the second supply mode. I am letting. Thereby, electric power can be supplied from the external charging system 21 to the low voltage system 32 without going through the high voltage battery 11, and energy efficiency at the time of external charging can be improved.

  In addition, when the temperature of the main converter 33 exceeds the normal range under the state where the first supply mode is being executed, the first supply mode is switched to the second supply mode. Thereby, since the main converter 33 can be stopped, the main converter 33 can be protected while maintaining the power supply to the low voltage system 32 and continuing external charging. Further, when the temperature of the sub-converter 34 exceeds the normal range under the state where the second supply mode is being executed, the second supply mode is switched to the first supply mode. Thereby, since the sub-converter 34 can be stopped, the sub-converter 34 can be protected while maintaining the power supply to the low voltage system 32 and continuing external charging. In addition, when the temperature of the charger 23 exceeds the normal range under the state where the second supply mode is being executed, the second supply mode is switched to the first supply mode. Thereby, the heat generation of the sub-converter 34 can be stopped, and the temperature increase of the in-vehicle charging unit 41, that is, the charger 23 can be suppressed. That is, since the output limitation of the charger 23 due to the temperature rise can be suppressed, the charging of the high voltage battery 11 can be continued, and a significant extension of the charging time can be avoided.

[Other embodiments]
In the example shown in FIG. 1, the vehicle power supply device 10 includes the charger 23. However, the present invention is not limited to this, and the charger 23 is connected from the vehicle power supply device 10 by using a charging facility outside the vehicle. May be omitted. Here, FIG. 5 is a schematic diagram showing a configuration of a vehicle power supply device 50 according to another embodiment of the present invention. 5, parts that are the same as the parts shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 5, the vehicle power supply device 50 is provided with an external charging system 51 that supplies power from the external power supply 20 to the high voltage battery 11. The external charging system 51 energizes the high voltage battery 11. It has an inlet 25 connected via a line 52. When charging the high voltage battery 11 using the external power source 20, the connector 27 of the charging cable 26 extending from the charging facility 53 outside the vehicle is connected to the inlet 25. Thus, by connecting the charging cable 26 to the inlet 25, the external power source 20 is connected to the inlet 25 via the charging facility 53.

  As described above, even if the vehicle power supply device 50 does not have the charger 23, the mode switching control is executed based on the outside air temperature or the like as shown in the flowchart of FIG. An effect can be obtained. That is, when the outside air temperature or the temperature of the sub-converter 34 is low, the second supply mode for operating the sub-converter 34 is executed. Thereby, electric power can be supplied from the external charging system 51 to the low voltage system 32 without going through the high voltage battery 11, and the energy efficiency at the time of external charging can be improved. On the other hand, when the outside air temperature or the temperature of the sub-converter 34 is high, the first supply mode for operating the main converter 33 is executed. As a result, even if the temperature of the sub-converter 34 rises excessively during external charging, the power supply to the low voltage system 32 can be continued using the main converter 33, so the controller during external charging The power supply voltage such as 42 can be stabilized. Thereby, since external charge can be continued appropriately, the charge of the high voltage battery 11 can be continued and extension of charge time can be suppressed.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. The electric vehicle shown in the figure is an electric vehicle including only the motor generator 12 as a power source, but is not limited thereto, and may be a hybrid electric vehicle including a motor generator and an engine as power sources.

  In the above description, the mode switching control is executed based on the outside air temperature, the temperature of the main converter 33, the temperature of the sub-converter 34, and the temperature of the charger 23. However, the present invention is not limited to this. For example, the mode switching control may be executed based on at least one of the outside air temperature, the main converter 33 temperature, the sub-converter 34 temperature, and the charger 23 temperature. Further, the mode switching control may be executed based on the temperature such as the passenger compartment temperature or the battery temperature without being limited to the above-described temperatures.

  Further, a predetermined temperature T1 compared with the outside air temperature, a predetermined temperature T2 compared with the temperature of the main converter 33, a predetermined temperature T3 compared with the temperature of the sub-converter 34, and a predetermined temperature compared with the temperature of the charger 23 Each temperature of T4 is a temperature that is appropriately set based on the temperature at which protection control intervenes for each device. Note that the predetermined temperatures T1 to T4 are temperatures that are appropriately set according to the specifications of each device, but may be the same temperature or different temperatures.

  In the above description, the batteries 11 and 30 are used as the first power storage unit and the second power storage unit. However, the present invention is not limited to this, and a capacitor may be used as the first power storage unit or the second power storage unit. In the illustrated example, the electric vehicle is provided with the inlet 25. However, the present invention is not limited to this, and the electric vehicle may be provided with a charging cable. In this case, the charging cable on the electric vehicle side functions as a power supply connecting portion. In the example shown in FIG. 1, the charger 23 and the sub-converter 34 are incorporated in one case 40, but the present invention is not limited to this, and the charger 23 and the sub-converter 34 may be provided separately. good.

DESCRIPTION OF SYMBOLS 10 Power supply device 11 for vehicles High voltage battery (1st electrical storage body)
20 External power supply 23 Battery charger 25 Inlet (power supply connection part)
30 Low voltage battery (second power storage unit)
33 Main converter (first power converter)
34 Sub-converter (second power converter)
40 Case 42 Controller (Mode control unit)
50 Vehicle power supply device T1 predetermined temperature (first threshold)
T2 Predetermined temperature (second threshold)
T3 Predetermined temperature (third threshold)
T4 Predetermined temperature (fourth threshold)

Claims (6)

A vehicle power supply device comprising a first power storage unit and a second power storage unit having a lower voltage than the first power storage unit,
When charging the first power storage unit using an external power supply, a power supply connecting portion to which the external power supply is connected;
A first power converter provided between the first power storage unit and the second power storage unit and supplying power from the first power storage unit to the second power storage unit;
A second power converter that is provided between the power supply connection unit and the second power storage unit and supplies power from the power supply connection unit to the second power storage unit;
A first supply mode for supplying power to the second power storage unit via the first power converter during external charging in which the external power source is connected to the power connection unit; and A mode control unit for switching between a second supply mode for supplying power to the second power storage unit;
Have
The mode control unit is a vehicle power supply device that switches between the first supply mode and the second supply mode based on temperature. The vehicle power supply device according to claim 1,
The mode control unit executes the first supply mode when the outside air temperature exceeds the first threshold, and executes the second supply mode when the outside air temperature falls below the first threshold. Power supply. The vehicle power supply device according to claim 1 or 2,
When the temperature of the first power converter exceeds a second threshold under the state where the first supply mode is being executed, the mode control unit changes from the first supply mode to the second supply mode. Switch to the vehicle power supply. In the vehicle power supply device according to any one of claims 1 to 3,
When the temperature of the second power converter exceeds a third threshold value in a state where the second supply mode is being executed, the mode control unit starts from the second supply mode to the first supply mode. Switch to the vehicle power supply. In the vehicle power supply device according to any one of claims 1 to 4,
A charger that is provided between the power supply connection unit and the first power storage unit and supplies power from the power supply connection unit to the first power storage unit;
The vehicle power supply device in which both the charger and the second power converter are accommodated in one case. The vehicle power supply device according to claim 5,
The mode control unit switches from the second supply mode to the first supply mode when the temperature of the charger exceeds a fourth threshold value under a state where the second supply mode is being executed. Vehicle power supply device.

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