JP2013110914A - Electric vehicle chargeable from external power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of shortening charging time when an electric vehicle mounted with a main battery and an auxiliary battery is charged from an external power supply.SOLUTION: The present specification discloses the electric vehicle chargeable from the external power supply. The electric vehicle includes a main battery for supplying power to a motor, and the auxiliary battery for supplying power to an auxiliary. In the electric vehicle, when being charged from the external power supply, forced-charging to the main battery and charging to the auxiliary battery are performed after completion of normal charging to the main battery.

Description

  The present invention relates to an electric vehicle that can be charged from an external power source.

  2. Description of the Related Art There is known an electric vehicle that can travel by charging power from an external power source to a main battery and driving a motor using the power. In many cases, this type of electric vehicle has an auxiliary battery that outputs a low voltage to supply power to an auxiliary machine with a low rated voltage, separately from a main battery that outputs a high voltage to drive a motor. I have. Patent Document 1 describes a technique for charging both a main battery and an auxiliary battery with electric power supplied from an external power source.

JP 2010-36594 A

  In the technique of Patent Literature 1, when charging from an external power source, charging of the auxiliary battery is first executed by rapid charging control, and when the charging of the auxiliary battery is completed, the main battery is focused. Therefore, the power used for charging the main battery is reduced until the charging of the auxiliary battery is completed, and the time until the charging of the main battery is completed is prolonged. When charging from an external power source, for example, there is a power loss due to various factors such as a power loss in the charging device.If the charging time is prolonged, the power loss increases accordingly and the charging efficiency decreases. It will end up.

  In this specification, the technique which solves the said subject is provided. The present specification provides a technique capable of shortening the charging time when an electric vehicle equipped with a main battery and an auxiliary battery is charged from an external power source.

  The present specification discloses an electric vehicle that can be charged from an external power source. The electric vehicle includes a main battery for supplying electric power to the motor and an auxiliary battery for supplying electric power to the auxiliary machine. In such an electric vehicle, when charging from an external power source, after the normal charging to the main battery is completed, the charging to the main battery and the charging to the auxiliary battery are performed.

  In the present specification, charging the main battery in a state where the electric power that can be supplied from the external power source to the electric vehicle is utilized to the maximum is referred to as normal charging to the main battery. The normal charging of the main battery may be performed by so-called constant voltage charging control, or may be performed by constant power charging control. Further, in this specification, the charging to the main battery is performed after the normal charging to the main battery, and the charging to the main battery is performed in a state where the power that can be supplied from the external power source to the electric vehicle is sufficient. That's it. Push-in charging to the main battery may be performed by so-called constant current charging control or constant power charging control.

  In the above-described electric vehicle, when the main battery is normally charged, the auxiliary battery is not charged. Therefore, most of the electric power that can be supplied from the external power source can be used for charging the main battery. Normal charging of the main battery can be performed in a short time. After that, at the time of push-in charging to the main battery, the auxiliary battery is charged using the remaining power that can be supplied from the external power source. Even if the auxiliary battery is charged in parallel with the push-in charging to the main battery, the charging time is not prolonged. According to the above-described electric vehicle, since charging to both the main battery and the auxiliary battery can be completed in a short time, the influence of power loss during charging can be reduced and charging efficiency can be improved.

  The electric vehicle includes a charging device that converts electric power supplied from an external power source and outputs electric power supplied to the main battery and the auxiliary battery, and a step-down circuit provided between the charging device and the auxiliary battery. In addition, when charging from an external power supply, the power output from the charging device is increased, the auxiliary battery side voltage of the step-down circuit is adjusted low, and then the power output from the charging device is decreased to It is preferable to adjust the auxiliary battery side voltage higher. For example, when charging from an external power supply, first, the power output from the charging device is adjusted to a predetermined first power, and the auxiliary battery side voltage of the step-down circuit is adjusted to a predetermined first voltage. Next, the power output from the charging device is adjusted to a second power lower than the first power, and the auxiliary battery side voltage of the step-down circuit is adjusted to a second voltage higher than the first voltage.

  According to the electric vehicle described above, when charging from the external power source, first, the power output from the charging device is increased, and the auxiliary battery side voltage of the step-down circuit is adjusted to be low, thereby charging the auxiliary battery. Without any problem, the main battery can be charged normally. Thereafter, the electric power output from the charging device is lowered, and the auxiliary battery side voltage of the step-down circuit is adjusted to be high, so that the charging to the main battery can be performed while charging the auxiliary battery. The charging device and the step-down circuit are also used in a conventional electric vehicle that charges a main battery and an auxiliary battery from an external power source. According to the above electric vehicle, the charging time can be shortened by controlling the operation of the existing charging device and step-down circuit without adding a new device or the like for reducing the charging time to the electric vehicle. it can.

1 is a block diagram of a power system of a hybrid vehicle 10 according to a first embodiment. It is a figure which shows distribution of the electric power supplied from the external power supply 48 in a prior art. It is a figure which shows distribution of the electric power supplied from the external power supply 48 in 1st Example. It is a block diagram of the electric power system of the hybrid vehicle 100 of 2nd Example.

(First embodiment)
A hybrid vehicle 10 of the present embodiment will be described with reference to the drawings. FIG. 1 is a block diagram of a power system of the hybrid vehicle 10.

  The hybrid vehicle 10 can travel using the power of an engine (not shown) or can travel using the power of the main battery 12. When traveling using the power of the engine, a part of the power generated by the engine is directly transmitted to drive wheels (not shown), while the remaining power of the engine is used to generate power by the first motor 14. Then, the driving wheel is rotated by driving the second motor 16 with the electric power generated by the first motor 14. When starting the engine, the electric power from the main battery 12 is supplied to the first motor 14 so that the first motor 14 functions as a cell motor. When traveling using the power of the main battery 12, the driving wheels are rotated by driving the second motor 16 with the power from the main battery 12.

  The main battery 12 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The hybrid vehicle 10 can generate power with the first motor 14 using the power of the engine, and charge the main battery 12 with the power generated by the first motor 14. Further, when the traveling hybrid vehicle 10 decelerates, the regenerative power generation can be performed by the second motor 16, and the power generated by the second motor 16 can be charged to the main battery 12.

  The voltage of the main battery 12 is detected by the voltage sensor 18. The current flowing through the main battery 12 is detected by the current sensor 20. The current sensor 20 of the present embodiment can detect the magnitude of the forward current (discharge current) from the main battery 12, and can also detect the magnitude of the reverse current (charge current) to the main battery 12. it can.

  The main battery 12 is connected to the power system via an SMR (System Main Relays) 22. The SMR 22 includes main switches 24 and 26, a precharge switch 28, and a precharge resistor 30. The precharge switch 28 and the precharge resistor 30 are connected in series, and they are connected in parallel to the main switch 26. The SMR 22 constitutes a so-called precharge circuit.

  The first DC / DC converter 32 boosts the voltage of the power supplied from the main battery 12 to a voltage suitable for driving the first motor 14 and the second motor 16 as necessary. The first DC / DC converter 32 can also step down the voltage of the power generated by the first motor 14 or the second motor 16 to a voltage suitable for charging the main battery 12. The first DC / DC converter 32 can be called a step-up circuit or a step-down circuit. In this embodiment, the voltage of the main battery 12 is about 300V, and the voltage used for driving the first motor 14 and the second motor 16 is about 600V. Between the SMR 22 and the first DC / DC converter 32, a first smoothing capacitor 34 for smoothing the low-voltage side voltage of the first DC / DC converter 32 is provided.

  The three-phase inverter 36 converts the DC power supplied from the main battery 12 into three-phase AC power for driving the first motor 14 and the second motor 16. The three-phase inverter 36 can also convert three-phase AC power generated by the first motor 14 and the second motor 16 into DC power for charging the main battery 12. Between the first DC / DC converter 32 and the three-phase inverter 36, a second smoothing capacitor 38 that smoothes the high-voltage side voltage of the first DC / DC converter 32, and a discharge resistor 40 that discharges the second smoothing capacitor 38. Is provided.

  The hybrid vehicle 10 includes an auxiliary battery 44 that supplies electric power to an auxiliary machine 42 such as a power steering and an air conditioner. The auxiliary battery 44 is a secondary battery such as a lead battery. In this embodiment, the voltage of the auxiliary battery 44 is 13V to 14.5V. A second DC / DC converter 46 is provided between the SMR 22 and the auxiliary battery 44 to step down the voltage between the main battery 12 and the auxiliary battery 44. The second DC / DC converter 46 steps down the voltage on the main battery 12 side and outputs it to the auxiliary battery 44 side. As will be described later, the output voltage on the low voltage side of the second DC / DC converter 46 can be changed by the control device 60. The second DC / DC converter 46 can also be called a step-down circuit.

  The hybrid vehicle 10 is a so-called plug-in hybrid vehicle in which the main battery 12 and the auxiliary battery 44 can be charged from an external power supply 48. The external power supply 48 is a general commercial 100V power supply. In the present specification, charging from the external power supply 48 is also referred to as plug-in charging.

  Charging from the external power supply 48 is performed via an EVSE (Electric Vehicle Supply Equipment) 50. The EVSE 50 acquires power from the external power supply 48 via a household AC 100V outlet. By connecting the charging plug 52 extending from the EVSE 50 to the connector 54 of the hybrid vehicle 10, electric power is supplied from the EVSE 50 to the charging device 56.

  The charging device 56 is connected between the SMR 22 and the first DC / DC converter 32 via a charging relay 58. The charging device 56 includes a transformer, a rectifier, a stabilization circuit, and the like, converts AC power from the EVSE 50 into desired DC power, and supplies it to the power system of the hybrid vehicle 10.

  The control device 60 controls operations of the first DC / DC converter 32, the three-phase inverter 36, the second DC / DC converter 46, the charging device 56, and the like.

  Below, the operation | movement at the time of charging the hybrid vehicle 10 from the external power supply 48 is demonstrated. When charging the main battery 12 from the external power supply 48, normal charging is first performed, and then push-in charging is performed.

  In normal charging of the main battery 12, the operation of the charging device 56 is controlled so that the output power of the charging device 56 becomes a predetermined value (for example, 3 kW). Thereby, normal charging to the main battery 12 is performed.

  In the hybrid vehicle 10 of the present embodiment, the auxiliary battery 44 is not charged while the main battery 12 is normally charged as described above. Specifically, the low-voltage side voltage (voltage on the auxiliary battery 44 side) of the second DC / DC converter 46 is set to a voltage at which the auxiliary battery 44 is not charged, for example, the voltage lower limit value (for example, 13 V) of the auxiliary battery 44. Adjust to. As a result, while the main battery 12 is normally charged, the auxiliary battery 44 is not charged.

  When the normal charging to the main battery 12 is completed, the inrush charging to the main battery 12 is then performed. In the present embodiment, the operation of the charging device 56 is feedback-controlled so that the power charged to the main battery 12 becomes a target value (for example, 0.5 kW). The power charged in the main battery 12 can be calculated from the detection value of the voltage sensor 18 and the detection value of the current sensor 20.

  In the hybrid vehicle 10 of the present embodiment, the auxiliary battery 44 is charged in parallel with the above-described push charging to the main battery 12. Specifically, when indentation charging to the main battery 12 starts, the low voltage side voltage (voltage on the auxiliary battery 44 side) of the second DC / DC converter 46 is changed to a voltage at which the auxiliary battery 44 is charged, for example, The voltage is adjusted to the upper limit voltage (for example, 14.5V) of the auxiliary battery 44. As a result, the auxiliary battery 44 is charged in parallel with the push-in charging to the main battery 12.

  FIG. 2 shows the distribution of power supplied from the external power supply 48 via the EVSE 50 when charging the auxiliary battery 44 in parallel with the normal charging of the main battery 12 as in the prior art. Yes. A part of the power supplied from the EVSE 50 includes power consumption in the charging device 56 and the second DC / DC converter 46 (“system loss” in FIG. 2) and power consumption in the auxiliary device 42 (“auxiliary consumption” in FIG. 2). )). The remaining electric power supplied from the EVSE 50 is used for charging the main battery 12 and the auxiliary battery 44. The more power used for charging the main battery 12, the shorter the normal charging is. However, if the auxiliary battery 44 is charged in parallel with the normal charging of the main battery 12, the power used for charging the main battery 12 is reduced, and the charging time is prolonged accordingly. . By prolonging the charging time, the above system loss and auxiliary machine consumption are increased, and the charging efficiency is lowered.

  FIG. 3 shows the distribution of the power supplied from the external power supply 48 via the EVSE 50 when charging the auxiliary battery 44 in parallel with the push-in charging to the main battery 12 as in this embodiment. ing. Unlike the normal charging, in the inrush charging, the power used for charging the main battery 12 is originally small, and there is a surplus power that can be supplied from the EVSE 50. Therefore, even if charging to the auxiliary battery 44 is performed in parallel with the push-in charging to the main battery 12, the charging time is not prolonged. Since charging can be completed in a short time, the above system loss and auxiliary machine consumption can be reduced, and charging efficiency can be improved.

  As in this embodiment, the auxiliary motor battery 44 is charged by plug-in charging from the EVSE 50, so that the first motor 14 and the second motor 16 can generate regenerative power while the hybrid vehicle 10 is traveling. The opportunity to charge the auxiliary battery 44 with the reduced power is reduced. Thereby, the cruising range of the hybrid vehicle 10 can be extended.

(Second embodiment)
Hereinafter, the hybrid vehicle 100 of the present embodiment will be described with reference to FIG. The hybrid vehicle 100 of the present embodiment has substantially the same configuration as the hybrid vehicle 10 of the first embodiment. Hereinafter, the features of the hybrid vehicle 100 of the present embodiment that are different from the hybrid vehicle 10 of the first embodiment will be described.

  In the hybrid vehicle 100 of the present embodiment, the charging device 56 is connected between the main battery 12 and the SMR 22 via the charging relay 58. With such a configuration, it is possible to charge the main battery 12 while the SMR 22 is cut off, that is, with the main battery 12 disconnected from the power system.

  In the hybrid vehicle 100 of the present embodiment, the output of the charging device 56 is connected between the second DC / DC converter 46 and the auxiliary battery 44 via the third DC / DC converter 70. With this configuration, the auxiliary battery 44 can be charged even when the SMR 22 is cut off and the main battery 12 is disconnected from the power system, and therefore the second DC / DC converter 46 cannot operate. Is possible.

  In the hybrid vehicle 100 of the present embodiment, the third DC / DC converter 70 controls the charging of the auxiliary battery 44 in the plug-in charging. That is, when the main battery 12 is normally charged, the low-voltage side voltage (voltage on the auxiliary battery 44 side) of the third DC / DC converter 70 is set to a voltage at which the auxiliary battery 44 is not charged, for example, auxiliary equipment. It adjusts to the voltage lower limit value (for example, 13V) of the battery 44. As a result, while the main battery 12 is normally charged, the auxiliary battery 44 is not charged.

  In addition, when the inrush charging to the main battery 12 is performed, the low-voltage side voltage (the voltage on the auxiliary battery 44 side) of the third DC / DC converter 70 is changed to a voltage at which the auxiliary battery 44 is charged, for example, an auxiliary battery. It adjusts to the voltage upper limit (for example, 14.5V) of the machine battery 44. As a result, the auxiliary battery 44 is charged in parallel with the push-in charging to the main battery 12.

  Points to be noted regarding the technology described in the embodiments will be described. The hybrid vehicles 10 and 100 according to the embodiment include a main battery 12 and an auxiliary battery 44. The main battery 12 is a battery that stores electric power to be supplied to motors (first motor 14 and second motor 16) that output driving force for traveling. The auxiliary battery 44 is a battery that stores electric power supplied to the auxiliary machine. Auxiliary equipment is a general term for electric devices whose driving voltage is lower than that of a motor, and examples thereof include power steering and air conditioners. The output voltage of the auxiliary battery 44 (13V to 14.5V in the embodiment) is lower than the output voltage of the main battery 12 (300V in the embodiment).

  The hybrid vehicles 10 and 100 can charge the main battery 12 and the auxiliary battery 44 using an external power source. As a device for charging, an ACDC converter (charging device 56) that converts AC power supplied from the outside of the vehicle into DC power having a voltage higher than the output voltage of the main battery 12, and the output voltage of the ACDC converter are stepped down. A step-down converter (second DC / DC converter 46 or third DC / DC converter 70) is provided. The output of the ACDC converter is connected to the main battery 12 and the high voltage side of the step-down converter. The low voltage side of the step-down converter is connected to the auxiliary battery 44. Hybrid vehicles 10 and 100 charge only main battery 12 by setting the output voltage on the low voltage side of the step-down converter to the first voltage lower than the output voltage of auxiliary battery 44 during the first period from the start of charging. To do. After charging for a predetermined period in that state, the hybrid vehicles 10, 100 set the output voltage on the low voltage side of the step-down converter to a second voltage higher than the output voltage of the auxiliary battery 44 and compensate with the main battery 12. The machine battery 44 is charged.

  In addition, the hybrid vehicles 10 and 100 set the low voltage side output voltage of the step-down converter to the first voltage lower than the voltage of the auxiliary battery 44 during the first period, and the power output by the charging device 56 is large. Is set to the first power (3 kW in the embodiment). In the period following the first period, the low-voltage side output voltage of the step-down converter is set to a second voltage higher than the output voltage of the auxiliary battery 44, and the magnitude of the power output by the charging device 56 is set to the first level. The second power is set lower than the power (in the embodiment, 0.5 kW for the main battery charge + the power for the auxiliary battery charge, for example, 1.0 kW). The first period corresponds to the normal charging period in the embodiment, and the period following the first period corresponds to the indentation charging period in the embodiment. The first power output by the charging device 56 in the first period is preferably the maximum value that can be output by the charging device 56, but is not limited thereto.

  In the above embodiment, the case where the electric vehicle is the hybrid vehicle 10 or 100 has been described as an example. However, the technology disclosed in the present specification is also applied to the case where the electric vehicle is an electric vehicle that does not include an engine. It is also possible to do.

  In the above embodiment, the case where the normal charging to the main battery 12 is performed by the constant power charging control has been described. However, the normal charging to the main battery 12 may be performed by the constant voltage charging control.

  In the above embodiment, the case where the inrush charging to the main battery 12 is performed by the constant power charging control has been described. However, the intrusion charging to the main battery 12 may be performed by the constant current charging control.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

10, 100 Hybrid vehicle 12 Main battery 14 First motor 16 Second motor 18 Voltage sensor 20 Current sensor 22 SMR
24, 26 Main switch 28 Precharge switch 30 Precharge resistor 32 First DC / DC converter 34 First smoothing capacitor 36 Three-phase inverter 38 Second smoothing capacitor 40 Discharge resistor 42 Auxiliary machine 44 Auxiliary battery 46 Second DC / DC converter 48 External power supply 50 EVSE
52 Charging Plug 54 Connector 56 Charging Device 58 Charging Relay 60 Control Device 70 Third DC / DC Converter

Claims (2)

An electric vehicle that can be charged from an external power source,
A main battery for supplying power to the motor;
It has an auxiliary battery for supplying power to the auxiliary machine,
An electric vehicle that performs push-in charging to a main battery and charging to an auxiliary battery after normal charging to the main battery is completed when charging from an external power source. A charging device that converts electric power supplied from an external power source and outputs electric power supplied to the main battery and the auxiliary battery; and
It further includes a step-down circuit provided between the charging device and the auxiliary battery,
When charging from an external power supply, the power output from the charging device is increased, the auxiliary battery side voltage of the step-down circuit is adjusted low, and then the power output from the charging device is decreased to the auxiliary battery side voltage of the step-down circuit. The electrically powered vehicle according to claim 1, wherein

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