KR20170068714A - Method for estimating charging time of echo-friendly vehicle - Google Patents

Abstract

Determining whether a battery charging expected time has been corrected based on a voltage of the battery, a current supplied to the battery from an OBC (On Board Charger) in the vehicle, or an output power of the OBC at a time when charging starts; If it is determined that the correction is not required in the correction determination step, it is assumed that the maximum output power specification of the OBC is provided based on the charged amount of the battery at the time when the charging is started, A first arithmetic operation step of performing arithmetic operation; And a second calculation step of calculating a second battery charge estimation time by applying a preset correction value to the first battery charge estimation time when it is determined that the correction is necessary in the correction determination step, Provides a prediction method.

Description

[0001] METHOD FOR ESTIMATING CHARGING TIME OF ECHO-FRIENDLY VEHICLE [0002]

The present invention relates to a method of calculating the charging time of an environmentally friendly vehicle, and more particularly, to a charging method of an environmentally friendly vehicle which can correct an error in the estimated charging time when the SOC of the charging target battery is low, Time prediction method.

In recent years, electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) have been developed to replace precautionary measures and limited fluid energy to prevent the ever-increasing environmental pollution with new energy sources.

Electric vehicles (EV) and plug-in hybrid vehicles (PHEV) drive the motor with the power of the battery, ensuring more than a certain vehicle speed.

More specifically, the electric vehicle travels by using the electric power of the battery. When the driver operates the pedal, the controller controls the gate frequency of the inverter according to the amount of pedal depression of the pedal, thereby controlling the DC power of the battery by PWM (Pulse Width Modulation) So that current is supplied to the drive motor. Here, the driving motor generates a constant torque in accordance with the amount of current supplied from the inverter so that the electric vehicle can travel.

An electric vehicle can be charged using a commercial AC power source (220V in Korea) and a DC power source (maximum 500V in fast charging) at a constant charging time. Generally, in order to charge a high-voltage battery that supplies electric power for generating electric power of an electric vehicle, a battery is connected to a charger and a charge current supplied from the charger is utilized. Here, the battery charging method includes a slow charging method in which a low-speed charging is performed through a current applied from a general power source, and a rapid charging method in which a high-current is applied to charge in a short time. That is, the charged amount of the battery is determined by the current and time applied to the battery.

The time required to charge the high voltage battery is about 20 minutes for rapid charging and at least about 5 hours to at least 10 hours for slow charging. This may vary depending on the specifications of the charging power source. Even if the capacity of the slow charger is high, since the charging time becomes long when the external power supply specification is low, it is required to accurately indicate the time required for charging so that the driver can accurately recognize the charging end time.

As a method of predicting the charging time at the time of a slow charging, a method of predicting the charging time based on the initial actual charging amount (kW) of the battery at the start of charging is monitored. Generally, since the output (kW) of an on-borar charger (OBC) installed in a vehicle is almost constant in the case of a constant charge, the estimated time according to the charging power can be inferred.

However, even if the charging current (SoC) of the battery to be charged is low and the voltage thereof is low, even if the charging current is supplied at the maximum output current that can be provided by the OBC, the battery is charged to a power that does not meet the OBC maximum output power specification . Therefore, when the battery voltage is low, the estimated charging time can be calculated on the basis of the supply of power lower than the maximum output power that the OBC can provide at the start of charging. Accordingly, when the battery voltage increases and the charging power increases as the charging progresses, an error occurs that the actual charging time is shorter than the expected charging time.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

KR 10-2015-0074436 A KR 10-2013-0032493 A

Accordingly, it is an object of the present invention to provide a charging time predicting method of an environmentally friendly vehicle which can accurately predict a charging time by correcting the occurrence of an error in the expected charging time when the SOC of the charging target battery is low, To be a technical challenge.

According to an aspect of the present invention,

Determining whether a battery charging expected time has been corrected based on a voltage of the battery, a current supplied to the battery from an OBC (On Board Charger) in the vehicle, or an output power of the OBC at a time when charging starts;

If it is determined that the correction is not required in the correction determination step, it is assumed that the maximum output power specification of the OBC is provided based on the charged amount of the battery at the time when the charging is started, A first arithmetic operation step of performing arithmetic operation; And

A second calculation step of calculating a second battery charge estimation time by applying a predetermined correction value to the first battery charge estimation time when it is determined that the correction is necessary in the correction determination step;

The present invention also provides a method for estimating a charging time of an environmentally friendly vehicle.

According to an embodiment of the present invention, the step of determining whether the battery is being charged may include determining that it is necessary to correct the estimated battery charge time if the voltage of the battery is less than a predetermined reference voltage level.

According to an embodiment of the present invention, the determining whether or not the correction is performed may include determining that correction of the estimated battery charge time is required when the output current of the OBC is less than or equal to a preset reference current level.

In one embodiment of the present invention, the correction determining step determines that the estimated battery charging time is required when the output power of the OBC calculated based on the power input to the OBC from the slow charger is equal to or less than a predetermined reference power level And a step of judging.

In one embodiment of the present invention, the predetermined correction value can be preset according to the magnitude of the voltage of the battery at the time when charging is started.

According to another aspect of the present invention,

When the voltage of the battery is lower than a predetermined reference voltage level, the current supplied to the battery in an OBC (On Board Charger) in the vehicle is smaller than a predetermined reference current level, or the output power of the OBC The estimated charging time calculated based on the assumption that the maximum output power specification of the OBC is provided on the basis of the charged amount of the battery at the time when the charging is started, And estimating a charging time of the environmentally friendly vehicle.

According to the method for predicting the charging time of an environmentally friendly vehicle having the above-mentioned problem, the correction value is determined by considering the battery voltage and the specification of the OBC at the start of charging, and when the correction is required, It is possible to provide the driver with a more accurate estimation result of the charging time by calculating the estimated charging time calculated based on the assumption that the power specification is provided. Accordingly, the method of estimating the charging time of the environmentally friendly vehicle can further improve the convenience of the driver of the environmentally friendly vehicle.

1 is a configuration diagram showing a charging system to which a method for predicting a charging time of an environmentally friendly vehicle according to an embodiment of the present invention is applied.
2 is a flowchart showing a charging time predicting method of an environmentally friendly vehicle according to an embodiment of the present invention.
FIG. 3 is a graph showing the results of actual measurement of various parameters at the time of battery full charging to explain a charging time predicting method of an environmentally friendly vehicle according to an embodiment of the present invention.

Hereinafter, a charging time predicting method of an environmentally friendly vehicle according to various embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a configuration diagram showing a charging system to which a method for predicting a charging time of an environmentally friendly vehicle according to an embodiment of the present invention is applied.

Referring to FIG. 1, a charging system to which a method for predicting a charging time of an environmentally friendly vehicle according to an embodiment of the present invention is applied is a charging system that receives a voltage from a slow charging device, which is a kind of Electric Vehicle Supply Equipment (EVSE) (On Board Charger) 10, a vehicle battery 30 to be charged, and a control unit (for example, a battery management system (BMS)) 50.

The OBC 10 is mounted on an environmentally friendly vehicle such as a hybrid car or an electric car, and is connected to an external slow charging device through a constant charging port to charge the battery 20 of the vehicle. The OBC 10 may be implemented including high voltage switches, inductors, capacitors, isolated transformers, relays, and the like.

Here, the slow charger is a kind of electric vehicle supply equipment (EVSE), and the EVSE may be a charging equipment provided in a home or a charging stand provided in an automobile charging station such as a gas station. Accordingly, it should be understood that the slow charger described in the present specification and claims includes both an in-car control box (ICCB) or a charging circuit interrupt device (CCID) as a charging stand capable of charging a hybrid vehicle or an electric vehicle something to do.

The OBC 10 is connected to the slow charger through the slow charge port and receives the commercial AC power from the EVSE and converts it into the DC power. To this end, the OBC 10 receives a control pilot (CP) signal from the slow charger to check the voltage level.

In the embodiment of the present invention, the maximum output current specification and maximum output power specification that the OBC 10 can provide to the battery 30 are determined.

The control unit 50 receives power from the OBC 10 and determines whether the vehicle battery 30 is charged according to a predetermined program. The controller 50 may be a battery management system (BMS) for checking and managing the state of the battery. The control unit 50 may calculate the average value of the voltage level of the CP signal by sampling the CP signal received by the OBC 10 to determine whether to charge the battery. In particular, in an embodiment of the present invention, the controller 50 may calculate the current provided to the OBC 10 from the slow charger using the CP signal duty. For this calculation, the control unit 50 may be implemented with one or more processors operated by the set program, and the set program may be configured to perform each step of the method of predicting the charging time of the environmentally friendly vehicle according to an embodiment of the present invention It may be programmed.

The vehicle battery 30 is mounted on a hybrid vehicle or an electric vehicle and supplies power to the drive motor. The vehicle battery 30 may be a battery pack configured in a pack form by connecting cells in series according to the required capacity of the battery. Therefore, it should be understood that the vehicle battery 30 of the present specification and claims means all batteries including a battery pack used in a hybrid vehicle or an electric vehicle.

Hereinafter, a method for estimating the charging time of the environmentally friendly vehicle according to the embodiment of the present invention will be described in detail with reference to FIG. 2 and FIG.

2 is a flowchart showing a charging time predicting method of an environmentally friendly vehicle according to an embodiment of the present invention.

As shown in FIG. 2, the charging time predicting method for an environmentally friendly vehicle according to an embodiment of the present invention is a method for predicting charging time of an environmentally friendly vehicle, such as a battery voltage, an OBC (On Board Charger) (S10) for determining whether to compensate for the estimated battery charging time in accordance with the current or the output power of the OBC; and determining whether or not the charging is started A first calculation step (S20) of calculating a first battery charge estimation time on the assumption that a maximum output power specification of the OBC is provided on the basis of a charged amount of the battery of the OBC; and a step A second calculation for calculating a second battery charge estimation time by applying a preset correction value to the first battery charge estimation time, Step S30 may be included.

The step S 10 of determining whether the correction of the battery charging time is necessary is performed when the voltage of the battery 30 is equal to or lower than a predetermined reference voltage level. A step S13 of determining that the estimated battery charge time is required to be corrected, and a step S13 of determining whether or not the output power of the OBC calculated based on the power input to the OBC from the slow battery charger is equal to or less than a preset reference power level. And a step of determining that correction is necessary (S15).

Although FIG. 2 shows that step S11, step S13, and step S15 are sequentially executed as an example of the present invention, the present invention is not limited to the steps of executing the form or steps including all these steps But is not limited to the order.

First, in step S11, the control unit 50 compares the voltage of the battery 30 at the start of charging with a predetermined reference voltage level A. The control unit 50 may already include a means for detecting the voltage of the battery 30 when the control unit 50 is a normal battery management system (BMS), and if the voltage of the battery 30 is detected And can be provided to the control unit 50.

Here, the reference voltage level A can be determined as the maximum voltage at which the OBC 10 can not provide the maximum output power, even if the maximum output current specification of the OBC 10 is provided. For example, if the maximum output current specification of the OBC 10 is 20 A and the maximum output power specification is 6.6 kW, if the voltage of the battery 30 is less than 330 V by discharging, The maximum output power that can be provided is less than 6.6 kW. Therefore, the reference voltage level A can be determined to be a value near to about 330 V. When the voltage of the battery 30 is equal to or lower than the reference voltage level A at the start of charging, the OBC 10 provides the maximum output power It can be judged that correction for the prediction of the charging time is necessary.

Next, step S13 is a step of comparing the magnitude of the current output to the battery from the OBC 10 with a preset reference current level B. The output current of the OBC 10 can be easily detected by the normal current detecting means provided at the output terminal of the OBC 10. [

Here, the reference current level B may be determined in consideration of a predetermined margin in the maximum output current specification of the OBC 10. If the maximum output current specification of the OBC 10 is 20 A and the maximum output power specification is 6.6 kW as in the above example, if the voltage of the battery 30 is less than 330 V by discharging, the OBC 10 It always outputs the current corresponding to the maximum output current specification. When the voltage of the battery 30 is higher than 330 V, the output current exceeds the maximum output power specification, so that the output current must be smaller than the maximum output current specification. Thus, the reference voltage level B can be determined at a margin of 20 A, which is the maximum output current specification (e.g., about 19.5 A). When the voltage of the battery 30 is higher than the reference current level B at the start of charging, the OBC 10 can not provide the maximum output power and it can be determined that correction for the charging time prediction is necessary have.

Next, in step S15, the output power of the OBC 10 is calculated in consideration of the power supplied to the OBC 10 in the slow charger, and the output power of the OBC 10 is set to a predetermined reference power level C .

As described above, the slow charging device upon charging by the slow charging charger outputs a control pilot signal to the OBC 10. The control pilot signal is a pulse width modulated signal. According to the IEC 61851-1 standard, the amount of current that can be supplied by the OBC 10 is expressed by Equation 1 below in an AC charge current range of 6A to 51A And may be displayed by adjusting the pulse width of the control pilot signal.

[Formula 1]

Charge current = duty ratio (%) of control pilot signal * 0.6

By multiplying the duty ratio of the control pilot signal by the output voltage of the slow charging device, the power supplied to the OBC 10 can be calculated and multiplied by the efficiency specification of the OBC 10, Can be calculated.

As described above, when the voltage of the battery 30 is not sufficient at the start of charging, even if the OBC 10 outputs power at the maximum output current specification, the battery can not be charged at the maximum output power specification. Therefore, the reference power level C is determined by taking into account the maximum output power specification of the OBC 10 or a certain margin thereof, so that the output power of the OBC 10 is equal to or lower than the reference power level C It can be judged that correction for the prediction of the charging time is necessary.

The results of actual measurement of the various parameters at the time of battery full charge charging are shown in Fig. 3 with respect to the above-described steps S11, S13, and S15.

3, even if the output current of the OBC 10 is 20 A, which is the maximum output current specification, when the voltage of the battery 30 is low at the initial stage of charging (about 310 V in the example of FIG. 3) Is smaller than the maximum output power specification. This state is maintained for about 500 seconds when the voltage of the battery rises to about 330 V. Conventionally, since the charging time is predicted in consideration of the output power of the OBC 10 (about 6.2 kW in the example of FIG. 3) and the remaining capacity of the battery at the start of charging, The charging time can be predicted longer than the actual charging time because the case of outputting the output power specification can not be considered.

Accordingly, the present invention has a step of checking whether the predicted charge time needs to be corrected through the step of determining whether or not the correction is made as described above.

If it is determined in step S10 that the correction is not necessary, the output power of the OBC 10 is applied based on the charged amount of the battery 30 at the time when the charging is simply started, (S20). At this time, the charging power at the start of charging may be the maximum output power specification of the OBC 10.

For example, if the required charging capacity of the battery is 27 kWh at the start of charging and the maximum output power specification of the OBC 10 is 6.6 kW, then in step S20, 27 kWh / 6.6 kW 4.1h (about 4 hours 6 minutes) '.

If it is determined that the correction has been made in the step of determining whether the correction has been made (S10), the maximum output power of the OBC 10 is applied as calculated in step S20, Can be applied to correct the predicted charging time.

Here, the correction value may be a value previously set based on the voltage of the battery 30 at the start of charging. For example, it is possible to determine an appropriate correction value for each voltage value of the battery 30 at the start of charging by using an experimental method, and to preliminarily program it in the control unit 50 for application.

For example, in the example of FIG. 3, in the state where the chargeable capacity of the battery is 27 kWh, the estimated charging time calculated by the maximum output power specification (6.6 kW) of the OBC 10 is 241 minutes and the actual charging time is 253 minutes . That is, the difference was 5%. Thus, if the initial charging battery voltage is about 310 V, the correction value can be predetermined to 5% in advance.

Accordingly, in step S30, the charging time is first calculated using the chargeable battery capacity at the charging start time and the maximum output power specification of the OBC 10, the correction value 5% is applied to the calculated charging time, The charging time can be predicted. The finally estimated charging time may be displayed to the driver charging the vehicle.

As described above, in the method of predicting the charging time of the environmentally friendly vehicle according to the embodiment of the present invention, it is determined whether the correction value is applied in consideration of the voltage of the battery 30 and the specification of the OBC 10 at the start of charging, It is possible to provide the driver with a more accurate estimation result of the charging time by calculating the estimated charging time calculated based on the assumption that the OBC maximum output power specification is provided.

Although the present invention has been shown and described with respect to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as hereinafter claimed It will be apparent to those of ordinary skill in the art.

10: On Board Charger (OBC) 30: Battery
50:

Claims (6)

Determining whether a battery charging expected time has been corrected based on a voltage of the battery, a current supplied to the battery from an OBC (On Board Charger) in the vehicle, or an output power of the OBC at a time when charging starts;
If it is determined that the correction is not required in the correction determination step, it is assumed that the maximum output power specification of the OBC is provided based on the charged amount of the battery at the time when the charging is started, A first arithmetic operation step of performing arithmetic operation; And
A second calculation step of calculating a second battery charge estimation time by applying a predetermined correction value to the first battery charge estimation time when it is determined that the correction is necessary in the correction determination step;
And estimating a charging time of the environmentally friendly vehicle. The method according to claim 1,
Wherein the step of determining whether or not the correction is to be performed comprises the step of determining that a correction of the estimated battery charging time is necessary when the voltage of the battery is less than or equal to a predetermined reference voltage level. The method according to claim 1,
Wherein the determining whether or not the correction of the battery charging time is necessary includes determining that correction of the estimated battery charging time is necessary when the output current of the OBC is less than or equal to a preset reference current level. The method according to claim 1,
Wherein the step of determining whether or not the battery is fully charged includes determining that correction of the estimated battery charge time is required when the output power of the OBC calculated based on the power input to the OBC in the slow battery charger is equal to or lower than a predetermined reference power level Wherein said method comprises the steps of: The method according to claim 1,
Wherein the predetermined correction value is preset according to the magnitude of the voltage of the battery at the time when charging is started. When the voltage of the battery is lower than a predetermined reference voltage level, the current supplied to the battery in an OBC (On Board Charger) in the vehicle is smaller than a predetermined reference current level, or the output power of the OBC The estimated charging time calculated based on the assumption that the maximum output power specification of the OBC is provided on the basis of the charged amount of the battery at the time when the charging is started, And calculating a charging time of the environmentally friendly vehicle.

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