JP4752487B2 - Power supply device for vehicle and vehicle - Google Patents

Description

  The present invention relates to a vehicle power supply device and a vehicle, and more particularly to a vehicle power supply device and a vehicle including a voltage conversion device that is connected between two power storage devices having different output voltages and performs voltage conversion.

Regarding control of a conventional quick charger for a battery, for example, Japanese Patent Laid-Open No. 8-84438 (Patent Document 1) discloses a technique for preventing overheating of a transformer by limiting a charge output current when the temperature of the transformer reaches a predetermined value. It discloses about.
JP-A-8-84438

  In recent years, electric vehicles and hybrid vehicles in which a high-voltage battery exceeding 100 volts is mounted as a power storage device and a motor is mounted for driving have appeared. In such an automobile, as in the conventional vehicle, many loads driven by a 12-volt battery are used, and charging from the high voltage battery to the low voltage battery is performed using a DC / DC converter.

  Since vehicles have a wide operating temperature range, devices such as DC / DC converters are often provided with cooling devices to prevent overheating.

  In such a vehicle, the charging of the 12-volt auxiliary battery may be insufficient if the current is simply limited as in the technique disclosed in Japanese Patent Laid-Open No. 8-84438 (Patent Document 1). Conceivable.

  For example, even if the output power of the DC / DC converter is limited, the temperature of the DC / DC converter does not drop easily if an abnormality occurs in the cooling device that cools the output power. If this situation is left unattended, the auxiliary battery may not be sufficiently charged and the battery voltage may be reduced. Therefore, it is desirable to promptly detect and notify the occurrence of a failure even when the cooling device is abnormal.

  An object of the present invention is to provide a vehicle power supply device capable of quickly detecting an abnormality of a cooling device that cools a voltage conversion device, and a vehicle including the same.

  In summary, the present invention provides a power supply device for a vehicle, connected between first and second power storage devices having different output voltages, and charging the second power storage device from the first power storage device. A voltage conversion device that performs voltage conversion when performing, a cooling device that cools the voltage conversion device, a temperature detection unit that detects the temperature of the voltage conversion device, and an output restriction on the voltage conversion device according to the output of the temperature detection unit And a control device that determines an abnormality of the cooling device based on a predetermined determination condition. The predetermined determination condition includes that the time during which the output restriction is performed is a predetermined time or more.

  Preferably, the predetermined determination condition further includes that the second power storage device is in an insufficiently charged state.

  Preferably, when the control device determines that there is an abnormality in the operation of the cooling device, the control device performs a protection process for preventing a temperature rise of the voltage conversion device.

  More preferably, the vehicle power supply device further includes a connection device provided on a path for electrically connecting the first power storage device and the voltage conversion device. The control device controls the connection device to be in an open state as a protection process.

  Preferably, the output restriction is performed by decreasing the maximum output restriction value in a plurality of stages with respect to the temperature rise of the voltage conversion device. The control device determines that there is an abnormality in the operation of the cooling device when the state in which the maximum output limit value is the smallest among the plurality of stages of maximum output limit values continues for a predetermined period.

  Preferably, the cooling device includes an air cooling fan and an air passage that guides air blown by the air cooling fan to the voltage conversion device.

  Preferably, the power supply voltage of the first power storage device is higher than the power supply voltage of the second power storage device. A vehicle on which a vehicle power supply device is mounted includes a rotating electrical machine that receives power from a first power storage device and drives wheels, and an auxiliary device that receives power from a voltage conversion device and a second power storage device.

  In another aspect, the present invention is a vehicle on which any one of the above vehicle power supply devices is mounted.

  ADVANTAGE OF THE INVENTION According to this invention, the abnormality of the cooling device which cools a voltage converter is detected rapidly, and there exists an effect of helping to keep the state of a vehicle always good.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a block diagram showing a configuration of a vehicle 100 to which the present invention is applied. Vehicle 100 may be an electric vehicle, a hybrid vehicle, a fuel cell vehicle, or the like as long as it uses a main battery and an auxiliary battery.

  Referring to FIG. 1, vehicle 100 includes a high voltage battery 10, system main relays SMRB and SMRG, a boost converter 12, an inverter 14, and a motor M1.

  The high voltage battery 10 is a main battery of the motor M1 for driving the vehicle. For example, a nickel hydride battery, a lithium ion battery, or a large capacity capacitor for electric storage such as an electric double layer capacitor can be used.

  System main relay SMRB is provided between the positive electrode of high voltage battery 10 and power supply line PL1. System main relay SMRG is provided between the negative electrode of high voltage battery 10 and ground line SL.

  Boost converter 12 boosts the voltage between power supply line PL1 and ground line SL and outputs the boosted voltage between power supply line PL2 and ground line SL. Inverter 14 receives the DC voltage between power supply line PL2 and ground line SL as a power supply voltage, and is controlled to generate a three-phase AC current. Then, the motor M1 is driven by the inverter 14, and a differential gear and wheels (not shown) are rotated by the motor M1.

  Vehicle 100 further includes a 12-volt auxiliary battery 18, a voltage sensor 19 that monitors the voltage between terminals of auxiliary battery 18, a load 20 that is driven by auxiliary battery 18, power supply line PL 1, and ground line SL. And a DC / DC converter 16 that steps down the voltage between the two and supplies the auxiliary battery 18 with the voltage.

  Examples of the load 20 include an electric power steering, a brake hydraulic pump, a headlamp, an air conditioner fan motor, a power source of various ECUs (Electric Control Units), a power source for driving a system main relay, and the like.

  What is particularly important as the role of the auxiliary battery 18 is power supply voltage supply to the ECU when the vehicle is started and power supply to a relay driving coil (not shown) to the system main relays SMRB and SMRG. When the vehicle is started and the system main relays SMRB and SMRG are turned on and the operation of the DC / DC converter 16 is started, the load 20 is mainly supplied with power from the DC / DC converter 16.

  Vehicle 100 further includes a temperature sensor 22 that measures temperature T of DC / DC converter 16, a current sensor 23 that measures output current I output from the DC / DC converter, and a cooling device for DC / DC converter 16. A cooling device 24 and a control device 30 are included.

  Control device 30 performs switching control of system main relays SMRB and SMRG, boosting control of boost converter 12 and switching control of inverter 14, and receives a temperature T from temperature sensor and a current I from current sensor 23 to receive DC / The output of the DC converter is limited and the cooling device 24 cools the DC / DC converter. The control device 30 includes a plurality of ECUs such as an engine control ECU, a hybrid control ECU, a control unit in the IPM (intelligent power module) of the inverter 14 and the boost converter 12, and a battery control ECU. It may be realized by communication.

FIG. 2 is a conceptual diagram for explaining the cooling device 24 of FIG.
Referring to FIG. 2, vehicle 100 includes a front seat 50 and a rear seat 52 in the vehicle interior. The high voltage battery 10 and the DC / DC converter 16 described in FIG. 1 are disposed behind the rear seat 52 in the vehicle interior. The cooling device 24 sucks air from an air intake hole provided in a panel between the rear window and the rear seat 52 and blows air to the DC / DC converter 16 and the high voltage battery 10 by the fans 53 and 54, respectively. To cool both.

  Normally, the passenger compartment is air-conditioned and kept below 30 ° C. In such a case, the DC / DC converter 16 can be kept at an appropriate temperature by sucking the air in the passenger compartment and cooling it. The control device 30 switches the rotational speed of the fan 53 between high, medium, and low according to the temperature T of the DC / DC converter 16 detected by the temperature sensor 22.

  However, vehicles are often left under hot weather and the interior of the vehicle is hot. In such a case, in addition to the DC / DC converter 16 being at a high temperature, the air in the passenger compartment is also considerably hot until the vehicle is started and the air conditioning is activated in the room for a while. Yes. If such high-temperature air is blown to the DC / DC converter 16, the temperature may be increased.

  FIG. 3 is a diagram for explaining the output restriction executed by the DC / DC converter 16.

  Referring to FIG. 3, when the temperature is lower than T1, the maximum outputable current of the DC / DC converter is set to I1. When the temperature rises to the range of T1 to T2, this maximum current that can be output is limited to I2. When the temperature range further rises to between T2 and T3, the maximum outputtable current is further reduced to I3, and when the temperature exceeds T3, the maximum outputtable current is limited to zero.

  In the map of FIG. 3, a region where the temperature is lower than T1 is referred to as region A, a region where the temperature is between T1 and T2 is referred to as region B, and a region where the temperature is between T2 and T3 is referred to as region C.

  Normally, the temperature T and the current I of the DC / DC converter operate well at, for example, the point P1. However, if the cooling device does not work sufficiently, the temperature rises and the operating point moves from point P1 to point P2 as shown in the locus of FIG. When the operating point moves to P2, the amount of heat generation decreases due to the current limitation of the DC / DC converter, and the temperature starts to decrease. Go back and forth. If the load current decreases at P2, the operating point moves from point P2 to point P4.

  As described above, normally, even in a state where the maximum output current is required in the environment where the automobile is used, the operating point temporarily moves to the region C due to the heat generated by the DC / DC converter. However, if the operating point enters the region C, the output current is limited, the temperature of the DC / DC converter is lowered, and then the load current is reduced and the air conditioning is effective so that the cooling device operates normally. As a result, the operating point sequentially returns to region B and region A.

  However, when there is an abnormality in the cooling device, for example, when a leak occurs in the blower path or the blower fan breaks down, the operating point may stay in the region C for a long time. If this state continues for a long time, power may be taken out from the auxiliary battery 18 and the auxiliary battery voltage may decrease. The auxiliary battery 18 plays an important role particularly at the time of startup. In such a case, it is necessary to detect that there is an abnormality in the cooling device and warn the driver of this.

  FIG. 4 is a flowchart showing a control structure of a cooling device abnormality detection program executed by the control device 30 of FIG. The processing of this flowchart is called and executed from a predetermined main routine every predetermined time or every time a predetermined condition is satisfied.

  Referring to FIGS. 1 and 4, when the process is started, in step S <b> 1, control device 30 determines whether or not DC / DC converter 16 is operating. If not in operation, the process proceeds to step S13, and the control is moved to the main routine.

  On the other hand, if the DC / DC converter is operating, the process proceeds to step S2. In step S2, the temperature T of the DC / DC converter 16 is acquired from the temperature sensor 22 and the temperature is measured. Then, the process proceeds to step S3, and the output current I is measured by the current sensor 23.

  After step S3, in step S4, control device 30 determines whether temperature T and current I are in region C of the map shown in FIG.

  If the operating point is not in the area C of the map, the process proceeds to step S10. If the operating point is in the area C, the process proceeds to step S5.

  In step S5, it is determined whether or not the time at which the operating point is determined to be in the region C continues for a predetermined time. If there is an operating point in the region C for a predetermined time, it is highly likely that the cooling device has an abnormality.

  The cooling device may be abnormal when the determination in step S5 is YES. However, in this embodiment, the processing after step S6 is further performed. On the other hand, if the determination of the C region is not continuous for a predetermined time in step S5, the process returns to step S2 to perform the region determination again.

  Note that conditions may also be set for the shift lever position when the process proceeds from step S5 to step S6. For example, when the shift lever position is the P (parking) position, whether or not the state of the region C continues for a longer time (for example, 30 minutes or more) may be used as a condition for determining the failure of the cooling device.

  In step S6, it is determined whether or not voltage VB2 of auxiliary battery 18 is below a predetermined threshold value. If voltage VB2 is not below the threshold value, the process proceeds to step S10. If voltage VB2 is below the threshold value, the process proceeds to step S7.

  In step S7, it is determined whether or not the period of “VB2 <threshold value” continues for a predetermined time.

  If the period satisfying this condition is not continuous for a predetermined time, the process returns to step S6 and monitoring of the battery voltage is continued.

  On the other hand, if the period in which “VB2 <threshold value” is satisfied continues for a predetermined time, the process proceeds to step S8.

  In step S8, the control device 30 determines that an abnormality has occurred in the cooling device 24 that is cooling the DC / DC converter 16, and turns on the warning lamp. In step S9, the system main relays SMRB and SMRG are set to the open state by shifting to a state in which vehicle travel is not permitted, that is, the READYOFF state. Then, the process proceeds to step S13, and the control is moved to the main routine.

  When the process proceeds from step S4 or step S6 to step S10, a temporary determination is made that the cooling system of the DC / DC converter is normal. Then, the process proceeds to step S11.

  In step S11, it is determined whether or not the normal tentative determination performed in step S10 has continued for three trips. Note that one trip refers to a process in which the driver turns on the ignition key switching to run the vehicle, stops the vehicle, and turns off the ignition key switch.

  In step S11, when the normal tentative determination continues for three trips, the process proceeds to step S12, and the control device 30 determines that the cooling device 24 that cools the DC / DC converter 16 is normal and turns off the warning lamp.

  On the other hand, if the normal tentative determination has been made in step S11 but the three trips have not been continued yet, the process proceeds to step S13 as it is even if it is determined that the cooling system is abnormal and the warning lamp is turned on. Is returned to once.

  In the flowchart of FIG. 4, the vehicle is shifted to the driving disapproval state immediately after the warning lamp is turned on. For example, the warning lamp is turned on in advance when YES is obtained in step S5. It is also possible to shift to a running non-permitted state after leaving.

  Based on the above description, the embodiment of the present invention will be described again in general. Referring to FIG. 1 again, the vehicle power supply device disclosed in the present embodiment is connected between main high-voltage battery 10 and auxiliary battery 18 having different output voltages, and from battery 10 to battery 18. The DC / DC converter 16 that performs voltage conversion when charging is performed, the cooling device 24 that cools the DC / DC converter 16, the temperature sensor 22 that detects the temperature of the DC / DC converter 16, and the output of the temperature sensor 22 And a control device 30 that limits the output of the DC / DC converter 16 according to the above and determines whether the cooling device is abnormal based on a predetermined determination condition. The predetermined determination condition includes that the time during which the output restriction is performed is a predetermined time or more. Preferably, the predetermined determination condition further includes that auxiliary battery 18 is in an insufficiently charged state.

  Preferably, when control device 30 determines that there is an abnormality in the operation of cooling device 24, it performs a protection process to prevent the temperature rise of DC / DC converter 16.

  More preferably, the vehicle power supply device further includes system main relays SMGB and SMRG provided on a path that electrically connects main high-voltage battery 10 and DC / DC converter 16. The control device 30 controls the system main relays SMGB and SMRG to be in an open state as a protection process.

  Preferably, the output restriction is performed by decreasing the maximum output restriction value in a plurality of stages as shown in the map of FIG. 3 with respect to the temperature rise of the voltage converter. The control device 30 operates the cooling device when a state in which the maximum output limit value is the smallest among the maximum output limit values in a plurality of stages, that is, a state where the operating point is in the region C of the map of FIG. It is judged that there is an abnormality.

  Preferably, as shown in FIG. 2, the cooling device 24 includes an air cooling fan 53 and an air passage that guides air blown by the air cooling fan 53 to the DC / DC converter 16.

  Preferably, the power supply voltage of high voltage battery 10 is higher than the power supply voltage of auxiliary battery 18. A vehicle 100 on which a vehicle power supply device is mounted includes a motor M1 that receives electric power from a high-voltage battery 10 and drives wheels, and a load 20 as an auxiliary machine that receives electric power from a DC / DC converter 16 and an auxiliary battery 18. Including.

  As described above, in this embodiment, when an abnormality occurs in the cooling system of the DC / DC converter, this abnormality can be detected and notified to the driver. As a result, it is possible to prevent the driver from traveling for a long time while the vehicle is abnormal. Further, since the cooling system abnormality can be detected, it is possible to prevent the battery voltage from being lowered without being able to charge the auxiliary battery.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram showing a configuration of a vehicle 100 to which the present invention is applied. It is a conceptual diagram for demonstrating the cooling device 24 of FIG. FIG. 6 is a diagram for describing output restriction executed by a DC / DC converter 16. It is the flowchart which showed the control structure of the abnormality detection program of the cooling device performed with the control apparatus 30 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 High voltage battery, 12 Boost converter, 14 Inverter, 16 DC / DC converter, 18 Auxiliary battery, 19 Voltage sensor, 20 Load, 22 Temperature sensor, 23 Current sensor, 24 Cooling device, 30 Control device, 50 Front seat , 52 Rear seat, 53, 54 fan, 100 vehicle, M1 motor, PL1, PL2 power line, SMRB, SMRG system main relay, SL ground line.

Claims (6)

A voltage conversion device connected between first and second power storage devices having different output voltages, and performing voltage conversion when charging the second power storage device from the first power storage device;
A cooling device for cooling the voltage converter;
A temperature detector for detecting the temperature of the voltage converter;
A control device that performs output limitation on the voltage conversion device according to the output of the temperature detection unit, and determines abnormality of the cooling device based on a predetermined determination condition,
The predetermined judgment condition is:
It said method comprising the time you are driving the voltage converter while the output limit line that There are not less than a predetermined time, and said second power storage device is insufficiently charged state,
When the control device determines that the operation of the cooling device is abnormal, the control device performs a protection process different from the output restriction in order to prevent a temperature rise of the voltage conversion device. A connection device provided on a path for electrically connecting the first power storage device and the voltage conversion device;
The vehicle power supply device according to claim 1, wherein the control device controls the connection device to be in an open state as the protection process. The output limitation is performed by decreasing the maximum output limitation value in a plurality of stages with respect to the temperature rise of the voltage converter.
2. The control device according to claim 1, wherein the control device determines that there is an abnormality in the operation of the cooling device when a state in which the maximum output limit value is the smallest among the plurality of stages of maximum output limit values continues for a predetermined period. The power supply device for vehicles as described. The cooling device is
An air cooling fan,
The vehicle power supply device according to claim 1, further comprising: an air passage that guides air blown by the air cooling fan to the voltage conversion device. The power supply voltage of the first power storage device is higher than the power supply voltage of the second power storage device,
A vehicle equipped with the vehicle power supply device is
A rotating electrical machine that receives electric power from the first power storage device and drives a wheel;
The vehicle power supply device according to claim 1, comprising: an auxiliary machine that receives electric power from the voltage conversion device and the second power storage device.   A vehicle equipped with the vehicle power supply device according to claim 1.

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