KR20220163586A - Lauch control method and electronic vehicle using the same - Google Patents

Abstract

The present invention relates to a takeoff control method and an electric vehicle using the same. The electric vehicle may comprise: a first motor which drives a front wheel; a second motor which drives a rear wheel; a third motor, in takeoff control, connected to the first motor and the second motor; a first power transmission device, in the takeoff control, connecting the first motor and the third motor; and a second power transmission device, in the takeoff control, connecting the second motor and the third motor. Provided are the takeoff control method capable of sufficiently utilizing motor torque of the electric vehicle, and the electric vehicle using the same.

Description

Launch control method and electric vehicle using the same

The present disclosure relates to an oscillation control method and an electric vehicle using the same.

In order to improve the power shortage phenomenon in high-speed driving of an electric vehicle, a motor may be applied to each of the front and rear wheels of the electric vehicle. However, when two motors are applied to the front and rear wheels, the output of the front-wheel motors may not be fully utilized due to vehicle instability.

An oscillation control method capable of fully utilizing the motor torque of an electric vehicle and an electric vehicle using the same are provided.

In an electric vehicle according to one feature of the invention, a first motor driving front wheels, a second motor driving rear wheels, a third motor connected to the first motor and the second motor in starting control, in the starting control, A first power transmission device connecting the first motor and the third motor, and a second power transmission device connecting the second motor and the third motor in the start control may be included.

The electric vehicle may enter the start control when the accelerator pedal and the brake pedal of the electric vehicle are simultaneously stepped on.

While the accelerator pedal and the brake pedal are simultaneously depressed, the third motor may regenerate and control torque of the first motor and the second motor.

The electric vehicle may further include a battery charged by regeneration control of the third motor.

After entering the start control, if the brake pedal is not depressed, the torque of the third motor may increase with a predetermined slope.

In the start control, the brake hydraulic pressure of the electric vehicle may be maintained constant.

According to another feature of the present invention, a start control method of an electric vehicle including a first motor driving front wheels, a second motor driving rear wheels, and a third motor positioned between the first motor and the second motor , step in which the accelerator pedal and the brake pedal are simultaneously depressed, the first power transmission device and the second power transmission device, when the accelerator pedal and the brake pedal are simultaneously depressed, the first motor, the second motor, and the third motor Connecting, regenerating the torque of the first motor and the second motor by the third motor, and increasing the torque of the third motor at a predetermined slope when the brake pedal is not depressed. can include

The oscillation control method may further include charging a battery by controlling regeneration of the third motor.

The start control method may further include maintaining a constant brake hydraulic pressure of the electric vehicle in the start control.

An electric vehicle according to another feature of the invention includes first to third motors, a first power transmission device connected between the first motor and the third motor, and a first power transmission device connected between the second motor and the third motor. 2 power transmission unit, in the start control, control the first power transmission unit and the second power transmission unit to connect all of the first to third motors, and detect the entry of the start control; An oscillation control unit notifying the power transmission control unit of entering the oscillation control may be included.

The start control unit may detect the entry of the start control when the accelerator pedal and the brake pedal of the electric vehicle are simultaneously stepped on.

The electric vehicle includes a motor control unit for controlling the first to third motors so that the third motor regenerates and controls the torque of the first motor and the second motor while the accelerator pedal and the brake pedal are simultaneously depressed. can include more.

The motor control unit may control the third motor so that the torque of the third motor increases with a predetermined slope when the brake pedal is not depressed after entering the start control.

The electric vehicle may further include a brake control unit that receives the start control entry from the start control unit and constantly controls brake hydraulic pressure of the electric vehicle.

Provided is an oscillation control method capable of fully utilizing the motor torque of an electric vehicle and an electric vehicle using the same.

1 is a diagram schematically showing some configurations of an electric vehicle according to an embodiment.
2 is a diagram showing a configuration involved in starting control of an electric vehicle according to an embodiment.
3 is a flowchart illustrating start control of an electric vehicle according to an exemplary embodiment.
4 is a graph showing torques of motor 1, motor 2, and motor 3 according to oscillation control.
5 is a graph comparing the oscillation capability of an electric vehicle according to an embodiment with the conventional one.

This specification is a description of an electric vehicle including an intermediate motor together with a front wheel motor and a rear wheel motor. In the embodiment of the present specification, it is possible to secure zero-back performance by utilizing maximum torque more quickly in a stop/start situation using three driving motors.

Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings, but the same or similar reference numerals are given to the same or similar components, and overlapping descriptions thereof will be omitted. The suffixes "module" and/or "unit" for components used in the following description are given or used interchangeably in consideration of ease of writing the specification, and do not themselves have a meaning or role distinct from each other. In addition, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the embodiment disclosed in this specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in this specification, the technical idea disclosed in this specification is not limited by the accompanying drawings, and all changes included in the spirit and technical scope of the present invention , it should be understood to include equivalents or substitutes.

Terms including ordinal numbers, such as first and second, may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

When a component is referred to as being “connected” or “connected” to another component, it may be directly, mechanically, physically, or electrically connected or connected to the other component, but other components in the middle It should be understood that elements may be present. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

1 is a diagram schematically showing some configurations of an electric vehicle according to an embodiment.

As shown in FIG. 1 , the electric vehicle 1 includes three motors 1-3 (10, 20, 30) and two power transmission units 41 and 42. The power transmission device 41 is located between the motor 1 (10) and the motor 3 (30), and the motor 1 (10) and the motor 3 (30) are connected to the power transmission device (41) during launch control. connected to each other by The power transmission device 42 is located between the motor 2 (20) and the motor 3 (30), and in the start control, the motor 2 (20) and the motor 3 (30) are connected to each other by the connection of the power transmission device (42). . The connection between the motors means that the torque generated by one motor can be transmitted to another motor. The power transmission devices 41 and 42 are blocked during normal control rather than oscillation control, so motor 1 (10) and motor 3 (30) are not connected to each other, and motor 2 (20) and motor 3 (30) may not be connected to each other.

The power transmission device 41 and the power transmission device 42 may be implemented in a clutch method. For example, the connecting member 411 and the connecting member 412 may be connected in a clutch method, and the connecting member 421 and the connecting member 422 may be connected in a clutch method. However, the invention is not limited thereto, and various connection methods may be applied.

The electric vehicle 1 further includes an axle 71 connected to motor 1 10 and an axle 72 connected to motor 2 20, and front wheels 61 and 62 are connected to both ends of the axle 71, , Rear wheels 63 and 64 are connected to both ends of the axle 72 . Motor 1 (10) drives the front wheels (61, 62) through an axle (71), and motor 2 (20) drives the rear wheels (63, 64) through an axle (72).

The electric vehicle 1 further includes brakes 81 and 82 coupled to front wheels 61 and 62, brakes 83 and 84 coupled to rear wheels 63 and 64, and a hydraulic cylinder 80, and a hydraulic cylinder ( 80) supplies hydraulic pressure according to brake control to the brakes 81 to 84.

2 is a diagram showing a configuration involved in starting control of an electric vehicle according to an embodiment.

3 is a flowchart illustrating start control of an electric vehicle according to an exemplary embodiment.

4 is a graph showing torques of motor 1, motor 2, and motor 3 according to oscillation control.

As shown in FIG. 2 , the accelerator pedal sensor 111 is connected to the accelerator pedal 91 and generates an accelerator pedal detection signal APS according to the degree to which the accelerator pedal 91 is pressed by the driver. The brake pedal sensor 112 is connected to the brake pedal 92 and generates a brake pedal detection signal BPS according to the degree to which the brake pedal 92 is depressed by the driver.

The oscillation control unit 113 may detect an oscillation control use input (S1). The oscillation control unit 113 may detect an oscillation operation by receiving an accelerator pedal detection signal (APS) and a brake pedal detection signal (BPS). The launch control unit 113 may recognize that launch control is a necessary condition through a mechanical/electrical signal generated according to the driver's manipulation. For example, after the recognition unit of the AVN interface of the electric vehicle 1 is activated, when the accelerator pedal 91 and the brake pedal 92 are simultaneously depressed, the start control unit 113 detects this and enters start control. Specifically, the oscillation controller 113 determines whether the accelerator pedal detection signal APS is greater than or equal to a predetermined threshold value (a%) and the brake pedal detection signal BPS is greater than or equal to a predetermined threshold value (b%) (S2 ). If the result of S2 determination is “Yes”, the oscillation control unit 113 enters oscillation control. In the graph of FIG. 4 , time T0 is the entry point for oscillation control.

If it is “No” as a result of S2 determination, it is possible to continuously repeat step S2 to monitor entry.

The oscillation controller 113 is synchronized with the entry into the oscillation control and transmits a signal PCS to the power transmission control section 114 to notify the entry of the oscillation control. Upon receiving the signal PCS, the power transmission control unit 114 may transmit a power signal PS instructing power connection to the power transmission devices 41 and 42 . The power transmission devices 41 and 42 operate according to the power signal PS and are connected (S3). Then, motor 1 (10), motor 2 (20), and motor 3 (30) are all directly connected. This is referred to as “direct connection”.

The oscillation controller 113 is synchronized with the oscillation control entry and transmits a signal BCS to the brake control section 115 to inform the oscillation control entry. Upon receiving the signal BCS, the brake control unit 115 may transmit a brake control signal BS instructing to stop controlling the brake hydraulic pressure to the hydraulic cylinder 80 . The hydraulic cylinder 80 stops controlling the brake hydraulic pressure according to the brake control signal BS (S4). Then, since the hydraulic pressure applied to the brakes 81 to 84 is constant, the braking force applied to the front wheels 61 and 62 and the rear wheels 71 and 72 can be kept constant.

The oscillation controller 113 is synchronized with the entry into the oscillation control and transmits a signal MCS1 informing the motor controller 116 of the entry into the oscillation control to inform the entry of the oscillation control. Upon receiving the signal MCS1, the motor control unit 116 generates signals MS1 and MS2 for controlling the sum of the torques of the motor 1 10 and the motor 2 20 to a predetermined amount of torque, and A signal MS3 for regenerating control 3 (30) with a predetermined negative torque is generated, and the signals (MS1-MS3) are transmitted to motor 1-motor 3 (10, 20, 30) (S5). The motor controller 116 transmits torque detection signals TS1, TS2, and TS3 indicating torques of the motor 1 (10), the motor 2 (20), and the motor 3 (30) to the motor 1 (10) and the motor 2 ( 20), and motor 3 (30).

For example, the predetermined positive torque may be 6000 Nm, which is the sum of the maximum torques of the two motors 1 10 and 2 20, and the predetermined negative torque may be -6000 Nm. That is, when starting control is entered according to an embodiment, the power transmission devices 41 and 42 are connected, and the motor 1 and motor 3 (10, 20, and 30) are all connected to a direct connection state, and the motor 1 (10) And motor 2 (20) operates with the maximum torque required for oscillation, and motor 3 (30) regenerates the torque provided from motor 1 (10) and motor 2 (20) to control the stopping condition of electric vehicle (1). can be made According to the regeneration control, the power converter 93 can charge the battery 95 by converting the power supplied from the motor 3 30 .

Conventionally, in start control, the vehicle is stopped with brake hydraulic pressure, and the motor is operating in advance with the maximum torque that can be generated when starting. However, there is a limit to maintaining the vehicle in a stopped state due to a limit in brake hydraulic pressure. Then, there is a limit to the maximum torque that the motor can produce in the start control. That is, there is a limit to the oscillation capability.

Unlike this, in the present invention, the brake hydraulic pressure is maintained constant, and one of the three motors (motor 3) is used for regenerative braking, so that the remaining two motors (motor 1 and motor 2) can be controlled with maximum torque.

The oscillation controller 113 determines whether the brake pedal detection signal BPS is 0% (S6). That is, whether the driver has released the brake pedal is monitored by the launch controller 113 .

As a result of determining S6, the brake pedal detection signal BPS is 0%, and the oscillation controller 113 transmits a signal MCS2 instructing the start of oscillation to the motor controller 116. The motor controller 116 generates a signal MS3 for increasing the torque of the motor 2 20 with the maximum slope according to the signal MCS2 and transmits the signal MS3 to the motor 3 30 (S7). In the graph of FIG. 4 , time T1 is an oscillation start time.

The motor control unit 116 determines whether the torque of the motor 3 (30) has reached the maximum value (S8).

As a result of the determination in S8, when the torque of the motor 3 (30) reaches the maximum value, the motor controller 116 performs normal control (S9). Normal control means a motor control operation after the oscillation control is finished. Under normal control conditions, the brake hydraulic pressure is controlled according to the brake pedal. In the graph of FIG. 4 , time T2 is the time when the torque of motor 3 (30) reaches its maximum value.

As a result of the determination in S8, if the torque of the motor 3 (30) has not reached the maximum value, the motor control unit 116 maintains the control signal (MS3) for increasing the torque of the motor 3 (30) with the maximum slope.

In this way, even in the start standby state, the torque energy of the motor 1 (10) and the motor 3 (30) is recovered through the motor 3 (30), and the motor 1-motor 3 (10, 20, Since the speed of change of the torque output from 30) is much faster, the oscillation capability is improved.

5 is a graph comparing the oscillation capability of an electric vehicle according to an embodiment with the conventional one.

In the conventional vehicle shown in FIG. 5, the brake hydraulic pressure rise gradient upon starting is 2200 Nm/s. As indicated by the thick solid line in FIG. 5 , the torque of the motor is controlled below the brake hydraulic pressure during start control in a conventional vehicle.

Unlike this, in the present invention, by using regenerative braking of motor 2, torque of the motor can be used more than the brake hydraulic pressure when starting. As shown in FIG. 5, the slope of the torque increase of Motor 2 is 4000 Nm/s.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art in the field to which the present invention belongs are also the rights of the present invention. belong to the range

1: EV
10, 20, 30: motor 1-3
41, 42: power transmission device

Claims (14)

A first motor that drives the front wheels;
a second motor that drives the rear wheels;
In oscillation control, a third motor connected to the first motor and the second motor;
In the start control, a first power transmission device connecting the first motor and the third motor; and
and a second power transmission device connecting the second motor and the third motor in the start control. According to claim 1,
When the accelerator pedal and the brake pedal of the electric vehicle are simultaneously depressed, the electric vehicle enters the start control. According to claim 2,
While the accelerator pedal and the brake pedal are simultaneously depressed, the third motor regenerates and controls torques of the first motor and the second motor. According to claim 3,
The electric vehicle further comprising a battery charged by regeneration control of the third motor. According to claim 3,
After entering the start control, if the brake pedal is not depressed, the torque of the third motor increases with a predetermined slope. According to claim 1,
In the start control, the electric vehicle's brake hydraulic pressure is maintained constant. A starting control method for an electric vehicle comprising a first motor driving front wheels, a second motor driving rear wheels, and a third motor positioned between the first motor and the second motor,
depressing the accelerator pedal and the brake pedal at the same time;
connecting the first motor, the second motor, and the third motor by the first power transmission device and the second power transmission device when the accelerator pedal and the brake pedal are simultaneously depressed;
regenerating, by the third motor, torques of the first motor and the second motor; and
and increasing the torque of the third motor at a predetermined slope when the brake pedal is not depressed. According to claim 7,
Further comprising the step of charging the battery by the regeneration control of the third motor, the oscillation control method. According to claim 7,
In the start control, the start control method further comprising maintaining a constant brake hydraulic pressure of the electric vehicle. first to third motors;
a first power transmission device connected between the first motor and the third motor;
a second power transmission device connected between the second motor and the third motor;
In starting control, a power transmission control unit controlling the first power transmission device and the second power transmission device to connect all of the first to third motors; and
And an oscillation control unit that detects the entry of the oscillation control and informs the power transmission control section of the entry of the oscillation control. According to claim 10,
The oscillation control unit,
When the accelerator pedal and the brake pedal of the electric vehicle are simultaneously depressed, the start control entry is sensed. According to claim 11,
Further comprising a motor control unit for controlling the first to third motors so that the third motor regenerates the torque of the first motor and the second motor while the accelerator pedal and the brake pedal are simultaneously depressed. electric car. According to claim 12,
The motor control unit,
If the brake pedal is not depressed after entering the start control, the electric vehicle controls the third motor so that the torque of the third motor increases with a predetermined slope. According to claim 10,
The electric vehicle further comprising a brake control unit receiving the start control entry from the start control unit and constantly controlling brake hydraulic pressure of the electric vehicle.

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