KR101636153B1 - Charging the electric vehicle based on the torque control method - Google Patents

Abstract

The present invention relates to a charging-amount-based torque control method for an electric vehicle in which a charge state of a battery (current SOC; SOC _n ) is detected by controlling the magnitude of a torque according to a charged state of the battery to prevent the vehicle from suddenly stopping. Confirming whether the detected state of charge (SOC _n ) of the battery is a predetermined minimum state of charge (SOC _minimum ); Maintaining a torque intensity (T_req) required for a torque value of the motor when the detected charging state of the battery is greater than a predetermined minimum charging state as a result of the checking; Comparing a charged state of the detected battery with a predetermined minimum threshold value when the detected state of charge of the battery is smaller than a predetermined minimum state of charge; And controlling the motor torque while gradually decreasing the motor output proportionally to the battery charge state when the detected charge state of the battery is greater than the minimum limit value.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a charging torque control method for an electric vehicle (EV), and more particularly, And a control method.

In general, unlike an internal combustion engine, an electric vehicle drives a driving motor with electric energy stored in a high-voltage battery and rotates the wheels through a power transmitting device. As a non-polluting automobile, The development of low-pollution, pollution-free automobiles has been demanded as it emerges as a problem for all of us.

As shown in FIG. 1, such an electric vehicle shows a phenomenon in which the voltage is lowered as the state of charge (SOC) of the battery is lowered, and the torque intensity of the motor is naturally lowered as the voltage is lowered. When the voltage or charging state can no longer be output, the motor output is shut off to protect the battery.

For example, the, state of charge of the current battery, as shown in Fig. 2; if (Current SOC SOC _n) to detect and (S11), the state of charge of the detection of the battery (SOC _n) is a preset minimum state of charge (SOC _minimum) (S12). If the detected charge state of the battery is greater than the predetermined minimum charge state, the torque intensity of the motor is maintained at the _required torque intensity T _required (S13). Otherwise, if the detected charging state of the battery is smaller than the predetermined minimum charging state, the output of the motor is shut off (S14).

On the other hand, a conventional technique for controlling a vehicle based on a battery charging state in a hybrid vehicle is disclosed in the following Patent Document 1: Korean Patent Laid-Open Publication No. 10-2014-0079157 (published on June 26, 2014).

The conventional art disclosed in Patent Document 1 detects a required torque of a driver, calculates a sinking speed torque of the driving motor, detects a state of charge (SOC) of the battery, detects a state of charge of the battery, Based on the torque, selectively controls the engagement of the engine clutch according to the vehicle condition and the running condition.

Korean Patent Publication No. 10-2014-0079157 (published on June 26, 2014)

However, since the conventional electric vehicle and the related art as described above detect the charged state of the battery and shut off the torque of the motor when the charged state of the battery reaches the minimum charged state, there is a disadvantage that the vehicle can stop suddenly during operation have.

If the vehicle suddenly stops unintentionally while the vehicle is in operation, there is a danger that it could lead to a major accident.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the conventional electric automobile and the related art, and it is an object of the present invention to prevent the vehicle from suddenly stopping by controlling the torque magnitude according to the charged state of the battery And to provide a charge amount based torque control method for an electric vehicle.

It is another object of the present invention to provide a charging-amount-based torque control method of an electric vehicle in which the torque of a motor can be stably controlled by controlling the magnitude of the torque gradually in accordance with the charged state of the battery.

In order to achieve the object described above, the amount of charge based on the torque control method for an electric vehicle comprises: (a) the state of charge of a battery according to the present invention; detecting (Current SOC SOC _n); (b) confirming whether the detected state of charge (SOC _n ) of the battery is a predetermined minimum state of charge (SOC _minimum ); (c) maintaining a torque intensity (T_req) required for a torque value of the motor when the detected charge state of the battery is greater than a predetermined minimum charge state as a result of the check; (d) comparing the detected state of charge of the battery with a predetermined minimum threshold value when the detected state of charge of the battery is less than a predetermined minimum state of charge; (e) controlling the motor torque while gradually decreasing the motor output proportionally to the battery charge state when the detected state of charge of the battery is greater than the minimum threshold value.

Further, the charging-amount-based torque control method of an electric vehicle according to the present invention may further include the step of (f) blocking the motor torque when the detected state of charge of the battery is less than the minimum limit value.

In the step (e), the motor torque output is controlled based on the following formula.

Motor torque (Torque Value = T_req × (1- (SOC Minimum - SOC n) / (SOC Minimum - SOC Low _ Limit)

Wherein T_req is the motor torque, the minimum SOC _Minimum charge, _n is the current battery charge state SOC, SOC _{_ Low Limit} required represents a minimum limit value respectively.

According to the present invention, it is possible to prevent the vehicle from suddenly stopping by controlling the magnitude of the torque in accordance with the charged state of the battery.

According to the present invention, there is also an advantage that the torque of the motor can be stably controlled by controlling the magnitude of the torque gradually in accordance with the charged state of the battery.

1 is a conceptual diagram of torque control applied to a general electric vehicle,
2 is a flowchart showing a torque control method in a general electric vehicle,
3 is a configuration diagram of an electric vehicle to which the present invention is applied;
Fig. 4 is a conceptual diagram of torque control in the present invention,
FIG. 5 is a flowchart illustrating a method of controlling a charge amount state based torque of an electric vehicle according to a preferred embodiment of the present invention. FIG.

Hereinafter, a charging-amount-based torque control method for an electric vehicle according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

5 is a flowchart illustrating a charging-amount-based torque control method of an electric vehicle according to a preferred embodiment of the present invention.

A method for controlling charge-based torque of an electric vehicle according to a preferred embodiment of the present invention includes the steps of: (a) detecting (S101) a state of charge (current SOC; SOC _n ) of a battery; (b) confirming whether the detected state of charge (SOC _n ) of the battery is a predetermined minimum state of charge (SOC _minimum ) (S 102); (c) a step (S103) of maintaining the torque intensity of the motor at a required torque intensity (T_req) when the detected charging state of the battery is greater than a preset minimum charging state as a result of the check; (d) when the charged state of the battery detected is less than a minimum state of charge previously set, in step (S104) for comparing the state of charge and the pre-set minimum threshold (SOC _{_ Low Limit)} of the detected battery; (e) controlling the motor torque while gradually decreasing the motor output proportionally to the battery charge state when the detected state of charge of the battery is greater than the minimum threshold (S106); (f) closing the motor torque (Torque Value = 0) when the detected state of charge of the battery is smaller than the minimum limit value (S105).

The method of controlling the charge-based torque of the electric vehicle according to the preferred embodiment of the present invention will now be described in detail.

FIG. 3 is a block diagram of an electric vehicle to which the present invention is applied. The electric vehicle includes various instrument panels 1, a handle 2, an EPS (Electric Power Steering) 3, a brake pump 4, a brake 5, A selector switch / lever 7, an electric vehicle control unit (EVCU) 8, an air conditioner compressor 9, a heater 10, a quick charger 11, an electro mechanical brake (EMB) 12, a battery control unit (BCU) 13, a motor 14, a motor control unit (MCU) 15, a power electronics unit (PEU) 16, a battery management system (BMS) 17, Device 20, and a 12V battery 21.

In the electric vehicle according to the present invention, the charge amount of the battery is detected through interlocking between the electric vehicle control unit 8, the motor control unit 15 and the battery management system 17, and the torque of the motor is controlled based on the detection will be.

First, the charging-amount-based torque control method of an electric vehicle according to the present invention detects the state of charge (current SOC; SOC _n ) of the battery in step S101. In step S102, it is checked whether the detected state of charge (SOC _n ) of the battery is a predetermined minimum state of charge (SOC _minimum ) (SOC _n <SOC _Minimum ).

If it is determined in step S102 that the detected state of charge of the battery is greater than the preset minimum charge state, the process proceeds to step S103 and maintains the torque intensity T_req required for the torque value of the motor.

Alternatively, if the detected state of charge of the battery is smaller than the preset minimum charge state (SOC _n <SOC _Minimum), and moves to step S104 by comparing the minimum threshold (SOC _{_ Low Limit)} set in advance and the charging state of the detected battery (SOC _{n> _} SOC _{Low Limit?).}

If the detected state of charge of the battery is smaller than the minimum threshold value as a result of the comparison at step S104, the process proceeds to step S105 to cut off the motor torque (torque value = 0).

On the other hand, if the detected charge state of the battery is greater than the minimum limit value, the process proceeds to step S106, and the motor torque is controlled while gradually decreasing the motor output proportionally to the battery charge state, as shown in FIG.

Here, as a method of gradually reducing the motor output in proportion to the battery charging state, it is preferable to calculate the motor torque output value based on Equation (1) to control the motor torque.

[Equation 1]

Motor torque (Torque Value = T_req × (1- (SOC Minimum - SOC n) / (SOC Minimum - SOC Low _ Limit)

Wherein T_req is the motor torque, the minimum SOC _Minimum charge, _n is the current battery charge state SOC, SOC _{_ Low Limit} required represents a minimum limit value respectively.

As described above, according to the present invention, the charging state of the battery is detected, and if the detected state of charging the battery is the minimum charging state, the torque limit output of the motor is not immediately cut off as before, The motor torque is stably controlled by gradually reducing the output of the motor in consideration of the relation with the minimum limit value according to the state of charge of the battery. This solves the problem that the motor torque output is interrupted when the battery charging state reaches the minimum charging state and the vehicle suddenly stops.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

8: Electric vehicle control unit (EVCU) 15: Motor control unit (MCU)
17: Battery Management System (BMS)

Claims (3)

(a) detecting a state of charge (Current SOC; SOC _n ) of the battery;
(b) confirming whether the detected state of charge (SOC _n ) of the battery is a predetermined minimum state of charge (SOC _minimum );
(c) maintaining a torque intensity (T_req) required for a torque value of the motor when the detected charge state of the battery is greater than a predetermined minimum charge state as a result of the check;
(d) comparing the detected state of charge of the battery with a predetermined minimum threshold value when the detected state of charge of the battery is less than a predetermined minimum state of charge;
(e) controlling the motor torque while gradually decreasing the motor output proportionally to the battery charge state when the detected charge state of the battery is greater than the minimum limit value; And
(f) blocking the motor torque when the detected state of charge of the battery is smaller than the minimum limit value,
Wherein the step (e) controls the motor torque output based on the following equation.
<Formula>
Motor torque value (Torque Value = T_req x 1- (SOC _Minimum - SOC _n ) / (SOC _Minimum - SOC _{Low_Limit} )
Where T_req is the required motor torque, SOC _Minimum is the minimum charge state, SOC _n is the current battery charge state, and SOC _{Low_Limit} is the minimum threshold.
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