On-vehicle control device

Abstract

To suppress overheat of a charger when charging a battery using external power.SOLUTION: An on-vehicle control device mounted on a vehicle comprising a battery, a charger for charging the battery using external power and a current sensor for detecting a charging current value controls the charger in such a manner that a charging current value detected by the current sensor falls within a predetermined range from a charging command current value in a case where a voltage of the battery or a reflection value reflected with the voltage of the battery is less than a predetermined value when charging the battery by the charger using the external power.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle control device, and more particularly to an in-vehicle control device mounted on a vehicle equipped with a battery and a charger. [Background technology]

[0002] A conventional in-vehicle control device of this type has been proposed that, when it is determined that the battery is in a chargeable execution state in which charging from an external power source is executable, calculates the upper limit power that can be supplied from the power supply port based on the battery's SOC and battery temperature (see, for example, Patent Document 1). This device prevents the battery from entering an overvoltage state or an overcharge state, while enabling external power supply during external charging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-014820 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while the above-mentioned on-board control device can prevent the battery from overvoltage or overcharge, it can still cause the charger to overheat. When the battery voltage is low, the charging current value may exceed the charging command current value. In this case, an excessive current flows through the charger, causing it to overheat.

[0005] The main purpose of the in-vehicle control device of the present disclosure is to prevent the charger from overheating when charging the battery using external power. [Means for solving the problem]

[0006] The in-vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The in-vehicle control device of the present disclosure includes: A battery, a charger that charges the battery using external power; a current sensor for detecting a charging current value; An on-board control device that is mounted on a vehicle and controls the charger, When the battery is charged by the charger using external power, if the voltage of the battery or a value reflecting the voltage of the battery is less than a predetermined value, the charger is controlled so that the charging current value detected by the current sensor is within a predetermined range from the charging command current value. It is characterized by:

[0008] In the on-board control device disclosed herein, when a battery is charged by a charger using external power, if the battery voltage or a value reflecting the battery voltage is below a predetermined value, the charger is controlled so that the charging current value detected by the current sensor is within a predetermined range from the charging command current value. This prevents excessive current from flowing through the charger and prevents the charger from overheating. Here, the "value reflecting the battery voltage" can be the ratio of the remaining capacity to the total capacity of the battery (storage rate). The "predetermined range from the charging command current value" can be both the upper and lower limits, or only the upper limit. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of an electric vehicle 20 equipped with an on-board control device according to an embodiment of the present disclosure and a charging stand 80.

[0023] FIG. [Figure 2] 4 is a flowchart showing an example of a charging current adjustment process executed by a vehicle ECU 60. [Figure 3] 10 is an explanatory diagram showing an example of the relationship between the charge storage rate SOC of the battery 36, the current command Ic*, and the upper limit value (Ic*+Iref) of the charging current Ic. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with an on-board control device according to one embodiment of the present disclosure, and a charging stand 80. As shown in the figure, the electric vehicle 20 of the embodiment includes a driving motor 32, an inverter 34, a battery 36 as a power storage device, a drive power line 38, a system main relay 40, a charger 50, a vehicle connector 52 connected to a charging power line 51, a charging relay 54, and a vehicle electronic control unit (hereinafter referred to as "vehicle ECU") 60. The vehicle ECU 60 corresponds to the on-board control device.

[0011] The motor 32 is configured as, for example, a synchronous generator motor, and the rotor of the motor 32 is connected to a drive shaft DS that is connected to the drive wheels DW via a differential gear. The inverter 34 is connected to the motor 32 and also to a drive power line 38. The motor 32 is rotationally driven by switching control of a plurality of switching elements (not shown) of the inverter 34.

[0012] Battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to drive power line 38. System main relay 40 is provided on drive power line 38 and connects and disconnects inverter 34 and battery 36.

[0013] Charger 50 is connected by charging power line 51 to a portion of drive power line 38 closer to inverter 34 than system main relay 40, and is also connected to vehicle connector 52. Charger 50 charges battery 36 by adjusting the voltage of the charging power (charging voltage Vchg) supplied from charging stand 80. Vehicle connector 52 is configured to be connectable to stand connector 82 of charging stand 80 at home, a charging station, or the like. A charging relay 54 is provided on charging power line 51 between charger 50 and vehicle connector 52, and charging relay 54 connects and disconnects the vehicle connector 52 side and the drive power line 38 side.

[0014] Although not shown, the vehicle ECU 60 includes a microprocessor having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the vehicle ECU 60 via the input ports. Examples of signals input to the vehicle ECU 60 include a rotational position θm of the rotor of the motor 32 from a rotational position sensor (e.g., a resolver) 32a that detects the rotational position of the rotor of the motor 32. Examples of signals input to the vehicle ECU 60 include a voltage Vb of the battery 36 from a voltage sensor 36a attached between the terminals of the battery 36, a current Ib of the battery 36 from a current sensor 36b attached to the output terminal of the battery 36, and a temperature Tb of the battery 36 from a temperature sensor 36c attached to the battery 36. Another example of a signal input to the vehicle ECU 60 is a connection signal from a connection sensor 53 provided in the vehicle connector 52. Since the vehicle ECU 60 also functions as a drive control device for the vehicle, information necessary for driving control is also input to the vehicle ECU 60. Examples of this information include a start signal from a start switch, a shift position from a shift position sensor that detects the operating position of the shift lever, an accelerator opening from an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal, a brake pedal position from a brake pedal position sensor that detects the amount of depression of the brake pedal, and vehicle speed from a vehicle speed sensor.

[0015] Various control signals are output from the vehicle ECU 60 via the output port. The signals output from the vehicle ECU 60 include, for example, signals to a plurality of switching elements of the inverter 34. Examples of such signals include a switching control signal, a control signal to the system main relay 40, a drive control signal to the charger 50, and a control signal to the charging relay 54. The vehicle ECU 60 calculates the state of charge (SOC) of the battery 36 based on the current Ib of the battery 36 from the current sensor 36b. The vehicle ECU 60 is capable of wireless communication with a station electronic control unit (hereinafter referred to as "station ECU") 86 of the charging station 80 at home, at a charging station, or the like.

[0016] The charging stand 80 includes a stand connector 82, a power converter 84, and a stand ECU 86. The stand connector 82 is configured to be connectable to the vehicle connector 52 of the electric vehicle 20. The power converter 84 is connected to the stand connector 82 and an external power source 90 configured as an AC power source such as a household power source or a commercial power source. When the vehicle connector 52 and the stand connector 82 are connected and a command to charge the battery 36 is issued, the power converter 84 converts AC power from the external power source 90 into DC power and adjusts the power (voltage and current) before supplying it to the electric vehicle 20.

[0017] Although not shown, the stand ECU 86 includes a microprocessor having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the stand ECU 86 via the input port. Examples of the signals input to the stand ECU 86 include the output voltage Vout of the power converter 84 from a voltage sensor 84a attached between the output terminals of the power converter 84, and the output current Iout of the power converter 84 from a current sensor 84b attached to the output terminal of the power converter 84. Various control signals are output from the stand ECU 86 via the output port. Examples of signals output from the stand ECU 86 include a control signal to the power converter 84. The stand ECU 86 is capable of wireless communication with the vehicle ECU 60 of the electric vehicle 20.

[0018] In the electric vehicle 20 of this embodiment configured as described above, when the vehicle connector 52 and the stand connector 82 are connected while the vehicle is parked at home, a charging station, or the like with the system off, a connection signal is sent from the connection sensor 53 to the vehicle ECU 60, and the vehicle ECU 60 detects the connection between the vehicle connector 52 and the stand connector 82. When the user subsequently issues a command for external charging to charge the battery 36 using power from an external power source 90 (charging stand 80), the vehicle ECU 60 first turns on the system main relay 40 and the charging relay 54. The vehicle ECU 60 then sends a current command Ic* for external charging to the stand ECU 86, and the stand ECU 86 controls the power converter 84 so that the output current Iout of the power converter 84 becomes the current command Ic*. In this manner, external charging is performed. Then, when the charger 50 adjusts the charging power and the power storage percentage SOC of the battery 36 reaches a predetermined percentage Sch (for example, approximately 80% to 95%), the vehicle ECU 60 transmits a command to end external charging to the station ECU 86, and upon receiving this command, the station ECU 86 stops the power converter 84. In this way, external charging is terminated. Thereafter, the vehicle ECU 60 turns off the system main relay 40 and the charging relay 54.

[0019] Next, the operation of the electric vehicle 20 of this embodiment configured as described above, in particular the process of adjusting the charging current Ic by the vehicle ECU 60 during external charging, will be described. Figure 2 is a flowchart showing an example of the charging current adjustment process executed by the vehicle ECU 60.

[0020] When the charging current adjustment process is executed, vehicle ECU 60 first inputs current command Ic* as a charging current command value (step S100), and controls charger 50 so that battery 36 is charged by current command Ic* (step S110).

[0021] Next, it is determined whether the power storage rate SOC of the battery 36 is less than a threshold value Sref (step S120). The threshold value Sref can be a value slightly higher than the power storage rate SOC, which is the upper limit at which a state occurs where the charging current Ic exceeds the current command Ic* and becomes excessively large because the voltage of the battery 36 is relatively low. Therefore, the processing of step S120 may use the battery voltage as the threshold value Vref (a value corresponding to the threshold value Sref). However, the voltage Vb of the battery 36 during charging is adjusted by the charger 50 and therefore differs from the actual battery voltage. For this reason, in this embodiment, processing is performed using the power storage rate SOC, which reflects the actual battery voltage.

[0022] If it is determined in step S120 that the power storage percentage SOC of the battery 36 is equal to or greater than the threshold value Sref, it is determined that the charging current Ic will not become excessively large and greatly exceed the current command Ic*, and it is determined whether charging has ended (step S160). If it is determined that charging has not ended, the process returns to the process of inputting the current command Ic* in step S100. Therefore, if the power storage percentage SOC of the battery 36 is equal to or greater than the threshold value Sref, the processes of steps S100, S110, S120, and S160 are repeatedly executed until charging is ended.

[0023] If it is determined in step S120 that the storage percentage SOC of the battery 36 is less than the threshold value Sref, the charging current Ic (the current Ib of the battery 36) is input (step S130), and it is determined whether the charging current Ic is greater than the current command Ic* plus the tolerance Iref (step S140). The tolerance Iref is an allowable range within which the charging current Ic may exceed the current command Ic*, and may be 3% or 5% of the current command Ic*. Therefore, the sum of the current command Ic* and the tolerance Iref (Ic*+Iref) is the upper limit of the charging current Ic. Figure 3 shows an example of the relationship between the storage percentage SOC of the battery 36, the current command Ic*, and the upper limit (Ic*+Iref) of the charging current Ic.

[0024] If it is determined in step S140 that the charging current Ic is greater than the sum of the current command Ic* and the tolerance value Iref, i.e., if it is determined that the charging current Ic exceeds the upper limit (Ic*+Iref), the charger 50 is controlled to reduce the charging current Ic (step S150), and the process returns to step S120, where it is determined whether the battery 36's power storage percentage SOC is less than the threshold value Sref. The charger 50 can be controlled to reduce the charging voltage. On the other hand, if it is determined in step S140 that the charging current Ic is equal to or less than the sum of the current command Ic* and the tolerance value Iref, i.e., if it is determined that the charging current Ic is equal to or less than the upper limit (Ic*+Iref), the process returns to step S120 without adjusting the current. Therefore, the charging current Ic is adjusted to be equal to or less than the sum of the current command Ic* and the tolerance value Iref (upper limit) until the battery 36's power storage percentage SOC becomes equal to or greater than the threshold value Sref. This makes it possible to prevent the charger 50 from overheating due to an excessive current flowing through the charger 50.

[0025] In the electric vehicle 20 according to the embodiment described above, when the charger 50 charges the battery 36 using power from the external power supply 90, if the power storage percentage SOC of the battery 36 is less than the threshold value Sref, the charger 50 is controlled so that the charging current Ic is equal to or less than the sum of the current command Ic* and the allowable value Iref. This makes it possible to prevent the charger 50 from overheating due to an excessive current flowing through it.

[0026] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the battery 36 corresponds to the "battery", the charger 50 corresponds to the "charger", the current sensor 36b corresponds to the "current sensor", and the vehicle electronic control unit (vehicle ECU) 60 corresponds to the "on-vehicle control device".

[0027] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0028] The present disclosure has been described above using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be embodied in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0029] The present disclosure is applicable to the manufacturing industry of in-vehicle control devices, etc. [Explanation of symbols]

[0030] 20 electric vehicle, 32 motor, 34 inverter, 36 battery, 36a voltage sensor, 36b current sensor, 36c temperature sensor, 38 drive power line, 40 system main relay, 50 charger, 51 charging power line, 52 vehicle connector, 53 connection sensor, 54 charging relay, 60 vehicle ECU, 80 charging stand, 82 stand connector, 84 power converter, 84a voltage sensor, 84b current sensor, 86 stand ECU, 90 external power supply.

Claims

1. A battery, a charger that charges the battery using external power; a current sensor for detecting a charging current value; An on-board control device that is mounted on a vehicle and controls the charger, When the battery is charged by the charger using external power, if the voltage of the battery or a value reflecting the voltage of the battery is less than a predetermined value, the charger is controlled so that the charging current value detected by the current sensor is within a predetermined range from the charging command current value.

1. An in-vehicle control device comprising:

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