KR20100064642A - Control method for batter soc of hev - Google Patents

Abstract

PURPOSE: A method for controlling charge/discharge amount of a battery is provided to correct a current motor torque by selecting a correction motor torque according to a motor torque control line diagram using a goal SOC. CONSTITUTION: A method for controlling charge/discharge amount of a battery comprises the following steps; deciding a goal SOC; setting a motor torque control line diagram according the goal SOC; producing a correction motor torque about a current SOC in the motor torque control line diagram; and correcting the motor torque by adding the correction motor torque to the current motor torque.

Description

Control method for batter SOC of HEV of hybrid vehicle

The present invention relates to a method for controlling a battery charge / discharge amount of a hybrid vehicle, and more particularly, to predict vehicle driving conditions and driving conditions, set a target SOC according thereto, and then control to follow the target SOC to efficiently use energy. It relates to a battery charge and discharge amount control method of a hybrid vehicle.

In general, a hybrid vehicle refers to a vehicle driven by two power sources, and uses a battery as an energy storage device of the hybrid vehicle.

The remaining capacity control of the battery provided in the hybrid vehicle is an important parameter that determines fuel efficiency and exhaust performance of the hybrid vehicle, and the amount of assist and the regenerative braking amount may be determined according to the battery state of charge (SOC). to be.

The most important thing in controlling the battery remaining capacity is to allow the battery to be operated at the highest efficiency point, and the charge and discharge efficiency varies depending on the battery remaining capacity.

The remaining battery capacity is divided into three areas according to the characteristics of the charge / discharge efficiency, and an area corresponding to ± 5% of the battery remaining capacity based on 55% to 60% is a normal area, and the upper part of the normal area An area corresponding to 65% or more of the remaining battery capacity, which is a step, is an overcharge area, and an area that is 55% or less, which is a lower level of the normal area, is an overdischarge area.

Meanwhile, the battery charge / discharge control strategy of the existing hybrid vehicle is regarded as a passive state variable rather than an active control variable. Therefore, a strategic method of maintaining and controlling the SOC within a given operating area has been mainly adopted.

Representative hybrid vehicle SOC maintenance control methods include maximum SOC control, thermostat control, and baseline control.

In the above three SOC maintenance strategies, the maximum and minimum limit ranges of SOC values, which are state variables, are set. If the SOC values are within the limit ranges, no control strategy is performed.

Therefore, it is not a method of utilizing electric energy through active battery SOC control strategy. However, the above method can be seen as the most realistic alternative because it cannot predict the future situation of the vehicle, but if it is possible to predict the driving situation using GPS and navigation system, a control strategy different from existing technologies is possible.

The present invention has been made in view of the above, and when the vehicle driving conditions and driving conditions are predicted and the target SOC value is set accordingly, the motor torque control diagram that is variable according to the target SOC value is determined. The purpose of the present invention is to provide a method of controlling the charge / discharge amount of a hybrid vehicle in which a battery can be operated at the highest efficiency point according to the direction in which the driver is directed by deriving the motor torque for the current SOC according to the motor torque control diagram.

The above object is a method for controlling a charge / discharge amount of a battery of a hybrid vehicle,

Determining a target SOC; Setting a motor torque control diagram according to the target SOC; Deriving a corrected motor torque for a current SOC from the motor torque control diagram; Compensating the motor torque by adding the corrected motor torque to the current motor torque is achieved by the method of controlling the charge and discharge of the battery of the hybrid vehicle.

Preferably, the target SOC is determined while varying according to the driving time under the condition that prediction of the future situation of the vehicle is possible using any one selected from GPS, navigation, and intelligent transportation system.

As the target SOC approaches the limit maximum and minimum ranges, the amount of correction motor torque output from the motor increases as the slope increases.

According to another embodiment of the present invention, determining the target SOC further includes a minimum SOC and a maximum SOC.

In addition, the target SOC, the minimum SOC and the maximum SOC are determined by varying according to the driving time under the condition that the prediction of the future situation of the vehicle is possible using any one selected from GPS, navigation, and intelligent transportation system.

The motor torque control diagram is determined by varying every moment according to input values of the target SOC, the maximum SOC, and the minimum SOC, and is set to different inclinations according to the position between the maximum SOC and the minimum SOC based on the target SOC.

Accordingly, according to the method of controlling the battery charge / discharge amount of the hybrid vehicle according to the present invention, after setting a predictable target SOC for the future situation of the vehicle, the corrected motor torque is set by the motor torque control diagram which is set every minute according to the target SOC. By selecting and correcting the current motor torque, the battery can be operated at the highest efficiency point to suit the driver's direction by controlling the battery SOC with active control variables.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to the present invention, when the vehicle driving conditions and driving conditions are anticipated and the target SOC value is set accordingly, the motor torque control diagram variable according to the target SOC value is determined, and the motor torque control diagram according to the current SOC is determined. The present invention relates to a method for controlling a battery charge / discharge amount of a hybrid vehicle capable of efficiently operating an SOC in accordance with a driver's direction by deriving a motor torque.

Here, the target SOC (target SOC) can be set according to the driving time under the condition that it is possible to predict the future situation of the vehicle by using GPS, navigation and Intelligent Transportation Systems (ITS).

The target SOC is a variable value, and the motor torque control diagram is determined according to the target SOC. In this motor torque control diagram, the corrected motor is selected by selecting the corrected motor torque of the Y-axis variable corresponding to the current SOC of the X-axis variable. By adding the torque to the current motor torque (ADD), the current motor torque can be corrected to control the SOC in the direction desired by the driver.

1 is an explanatory diagram for explaining a conventional battery SOC control method.

In the figures, A to D represent 40, 48, 55, 62, and 70% SOC, respectively, and these values are fixed values and the diagrams are also fixed. At this time, the size of the motor torque is changed according to the state change amount of the SOC. However, the motor torque should be determined below the maximum motor torque value (± Tq Mot MAX) that the motor can produce at any motor speed in the physical sense. Of course, the A-D values are all changeable.

If the current SOC is in the range between B and C, the motor torque is 0, but this does not mean that the current motor torque is 0, but the correction motor torque is 0. Therefore, the motor torque to be corrected is 0, which means that the current motor torque is maintained as it is.

If the current SOC is between the C and D intervals, the torque to be motor assisted has a positive value, so that the corrected motor torque according to the SOC state is corrected by adding it to the current motor torque.

When the current SOC is in the A to B period, the torque to be generated by the motor has a negative value. Therefore, the correction motor torque according to the SOC state is corrected by subtracting the current motor torque from the above diagram.

The motor torque control diagram of FIG. 1 is implemented by the following equation.

Where u1 is the current SOC, u2 is the maximum motor torque, and A to D are constant.

2 is an explanatory diagram illustrating a method of controlling a battery SOC according to an exemplary embodiment of the present invention.

The target SOC is a value that varies depending on the driving time under the condition that it is possible to predict the future situation of the vehicle by using GPS, navigation, and ITS, and the motor torque control diagram is set at every moment according to the target SOC.

In the figure, either the right or left control line is selected based on a line passing through torque 0 (Nm) at SOC 55% (hereinafter referred to as C '), and on the right side of C' (in the direction of increasing SOC) If the target SOC is set at, the motor torque control diagram on the right side is selected based on the center line. If the target SOC is set on the left side (SOC reduction direction) based on C ', the motor torque control diagram on the left side based on the center line is selected. Is selected.

The motor torque control diagram is variable according to the target SOC. In the drawing, when the current SOC is in the C '~ C section, the corrected motor torque (-value) is added to the current motor torque to correct the current SOC in the C ~ D section. If present, correct the motor torque (+ value) by adding it to the current motor torque.

As shown, as the target SOC approaches the limit maximum and minimum SOC, the torque output from the motor also increases.

The motor torque control diagram of FIG. 2 is implemented by the following equation.

Where u1 is the target SOC, u2 is the maximum motor torque, u3 is the current SOC, and A to D are constant.

3 is an explanatory diagram for describing a method of controlling a battery SOC according to another exemplary embodiment of the present invention.

The target SOC, the maximum SOC, and the minimum SOC are values that vary depending on the driving time under the condition that the future of the vehicle can be predicted using GPS, navigation, and ITS, and the motor torque control diagram is shown in FIG. It is set every minute according to the target SOC, maximum SOC and minimum SOC.

The motor torque control diagram of FIG. 3 is determined based on three input values of the target SOC, the maximum SOC, and the minimum SOC, and different inclinations are set according to positions between the maximum SOC and the minimum SOC based on the target SOC. Compared to 2, it becomes more aggressive SOC control method.

For example, if the current SOC is between the minimum SOC and the target SOC, the corresponding motor torque (-value) in the motor torque control diagram is added to the current motor torque to compensate.

By setting the predictable target SOC for the future situation of the vehicle by this method, the motor torque is selected by the motor torque control diagram which is set every time according to the target SOC, and the current motor torque is corrected. The control variable can control the battery SOC.

Where u1 is the current SOC, u2 is the target SOC, u3 is the maximum SOC, u4 is the minimum SOC, and u5 is the maximum motor torque.

1 is an explanatory diagram for explaining a conventional battery SOC control method;

2 is an explanatory diagram for explaining a method of controlling a battery SOC according to an embodiment of the present invention;

3 is an explanatory diagram for explaining a method of controlling a battery SOC according to another embodiment of the present invention;

4 is a flowchart illustrating a method of controlling a battery charge / discharge amount of a hybrid vehicle according to an exemplary embodiment of the present invention.

Claims (6)

In the battery charge and discharge amount control method of a hybrid vehicle, Determining a target SOC; Setting a motor torque control diagram according to the target SOC; Deriving a corrected motor torque for a current SOC from the motor torque control diagram; And correcting the motor torque by adding the corrected motor torque to the current motor torque. The method according to claim 1, The target SOC is determined by varying according to the driving time under the condition that it is possible to predict the future situation of the vehicle by using any one selected from GPS, navigation and intelligent transportation system, the method of controlling the charge and discharge of the battery of the hybrid vehicle . The method according to claim 1, The target SOC is a method of controlling the charge / discharge amount of a hybrid vehicle, characterized in that the magnitude of the correction motor torque output from the motor increases as the slope increases as the limit maximum and minimum range is approached. The method according to claim 1, And determining the target SOC further includes a minimum SOC and a maximum SOC. The method according to claim 4, The target SOC, the minimum SOC and the maximum SOC is determined by varying according to the driving time under the condition that it is possible to predict the future situation of the vehicle using any one selected from GPS, navigation and intelligent transportation system hybrid vehicle characterized in that Battery charge and discharge control method. The method according to claim 4, The motor torque control diagram is determined by varying every moment according to the input values of the target SOC, the maximum SOC, and the minimum SOC, and is set to different slopes according to positions between the maximum SOC and the minimum SOC based on the target SOC. Battery charge and discharge control method of a hybrid vehicle.

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