Lauch control method and electronic vehicle using the same

Abstract

An electric vehicle may include a first motor for driving a front wheel, a second motor for driving a rear wheel, a third motor connected to the first motor and the second motor in the oscillation control, a first power transmission device connecting the first motor and the third motor in the oscillation control, and a second power transmission device connecting the second motor and the third motor in the oscillation control.

Description

Technology Field

[0001] The present disclosure relates to a oscillation control method and an electric vehicle using the same. Background Technology

[0002] To address the power shortage during high-speed driving of electric vehicles, motors can be applied to both the front and rear wheels of the electric vehicle. However, if two motors are applied to the front and rear wheels, the output of the front motor may not be fully utilized due to vehicle instability. The problem to be solved

[0003] The present invention aims to provide an oscillation control method capable of fully utilizing the motor torque of an electric vehicle and an electric vehicle utilizing the same. means of solving the problem

[0004] An electric vehicle according to one feature of the invention may include a first motor for driving a front wheel, a second motor for driving a rear wheel, a third motor connected to the first motor and the second motor in the oscillation control, a first power transmission device connecting the first motor and the third motor in the oscillation control, and a second power transmission device connecting the second motor and the third motor in the oscillation control.

[0005] The electric vehicle can enter the launch control when the accelerator pedal and the brake pedal of the electric vehicle are pressed simultaneously.

[0006] While the accelerator pedal and the brake pedal are pressed simultaneously, the third motor can regenerate the torque of the first motor and the second motor.

[0007] The electric vehicle may further include a battery that is charged by regenerative control of the third motor.

[0008] After entering the above oscillation control, if the brake pedal is not pressed, the torque of the third motor can increase at a predetermined slope.

[0009] In the above-mentioned oscillation control, the brake hydraulic pressure of the electric vehicle can be maintained at a constant level.

[0010] According to another feature of the invention, a starting control method for an electric vehicle comprising a first motor driving a front wheel, a second motor driving a rear wheel, and a third motor located between the first motor and the second motor may include the step of simultaneously pressing an accelerator pedal and a brake pedal; the step of connecting the first motor, the second motor, and the third motor when the accelerator pedal and the brake pedal are simultaneously pressed by a first power transmission device and a second power transmission device; the step of regeneratively controlling the torque of the first motor and the second motor by the third motor; and the step of increasing the torque of the third motor at a predetermined slope when the brake pedal is not pressed.

[0011] The above oscillation control method may further include a step of charging the battery by regenerative control of the third motor.

[0012] The above-described oscillation control method may further include a step in which the brake hydraulic pressure of the electric vehicle is maintained at a constant level during the oscillation control.

[0013] An electric vehicle according to another feature of the invention may include 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, a power transmission control unit that controls the first power transmission device and the second power transmission device to connect all of the first to third motors in the oscillation control, and an oscillation control unit that detects the entry into the oscillation control and notifies the power transmission control unit of the entry into the oscillation control.

[0014] The above-mentioned oscillation control unit can detect entry into the oscillation control when the accelerator pedal and the brake pedal of the electric vehicle are pressed simultaneously.

[0015] The electric vehicle may further include a motor control unit that controls 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 pressed simultaneously.

[0016] The motor control unit above can control the third motor such that if the brake pedal is not pressed after entering the oscillation control, the torque of the third motor increases at a predetermined slope.

[0017] The electric vehicle may further include a brake control unit that receives the oscillation control entry from the oscillation control unit and controls the brake hydraulic pressure of the electric vehicle at a constant level. Effects of the invention

[0018] A oscillation control method capable of fully utilizing the motor torque of an electric vehicle and an electric vehicle using the same are provided. Brief explanation of the drawing

[0019] FIG. 1 is a diagram schematically showing a part of the configuration of an electric vehicle according to one embodiment. FIG. 2 is a diagram showing a configuration involved in the oscillation control of an electric vehicle according to one embodiment. FIG. 3 is a flowchart illustrating the oscillation control of an electric vehicle according to one embodiment. Figure 4 is a graph showing the torque of motor 1, motor 2, and motor 3 according to oscillation control. FIG. 5 is a graph comparing the launch capability of an electric vehicle according to one embodiment with that of a conventional one. Specific details for implementing the invention

[0020] This specification describes an electric vehicle comprising a middle motor along with a front wheel motor and a rear wheel motor. The embodiments of this specification utilize three drive motors to utilize maximum torque more quickly in a standstill-start situation, thereby securing 0-100 km / h acceleration performance.

[0021] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components are assigned identical or similar reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "part" for components used in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not have distinct meanings or roles in themselves. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0022] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0023] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly mechanically, physically, or electrically connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0024] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0025] FIG. 1 is a diagram schematically showing a part of the configuration of an electric vehicle according to one embodiment.

[0026] As illustrated in FIG. 1, the electric vehicle (1) includes three motors 1-3 (10, 20, 30) and two power transmission devices (41, 42). A power transmission device (41) is located between motor 1 (10) and motor 3 (30), and during launch control, motor 1 (10) and motor 3 (30) are connected to each other by the connection of the power transmission device (41). A power transmission device (42) is located between motor 2 (20) and motor 3 (30), and during launch control, motor 2 (20) and motor 3 (30) are connected to each other by the connection of the power transmission device (42). The connection between the motors means that torque generated by one motor can be transmitted to another motor. The power transmission device (41, 42) is blocked during normal control rather than oscillation control, so that motor 1 (10) and motor 3 (30) are not connected to each other, and motor 2 (20) and motor 3 (30) are not connected to each other.

[0027] The power transmission device (41) and the power transmission device (42) may be implemented in a clutch manner. For example, the connecting member (411) and the connecting member (412) may be connected in a clutch manner, and the connecting member (421) and the connecting member (422) may be connected in a clutch manner. However, the invention is not limited thereto, and various types of connection methods may be applied.

[0028] The electric vehicle (1) further includes an axle (71) connected to a motor 1 (10) and an axle (72) connected to a motor 2 (20), and front wheels (61, 62) are connected to both ends of the axle (71), and rear wheels (63, 64) are connected to both ends of the axle (72). Motor 1 (10) drives the front wheels (61, 62) through the axle (71), and motor 2 (20) drives the rear wheels (63, 64) through the axle (72).

[0029] The electric vehicle (1) further includes brakes (81, 82) coupled to the front wheels (61, 62), brakes (83, 84) coupled to the rear wheels (63, 64), and a hydraulic cylinder (80), and the hydraulic cylinder (80) supplies hydraulic pressure to the brakes (81-84) according to brake control.

[0030] FIG. 2 is a diagram showing a configuration involved in the oscillation control of an electric vehicle according to one embodiment.

[0031] FIG. 3 is a flowchart illustrating the oscillation control of an electric vehicle according to one embodiment.

[0032] Figure 4 is a graph showing the torque of motor 1, motor 2, and motor 3 according to oscillation control.

[0033] As illustrated 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 pressed by the driver.

[0034] The launch control unit (113) can detect a launch control usage input (S1). The launch control unit (113) can detect a launch operation by receiving an accelerator pedal detection signal (APS) and a brake pedal detection signal (BPS). The launch control unit (113) can recognize that a launch control is required through mechanical / electrical signals generated according to the driver's operation. For example, after the recognition unit of the AVN interface of the electric vehicle (1) is activated, if the accelerator pedal (91) and the brake pedal (92) are pressed simultaneously, the launch control unit (113) detects this and enters launch control. Specifically, the launch controller (113) determines whether the accelerator pedal detection signal (APS) is greater than or equal to a predetermined threshold value (a%) and whether the brake pedal detection signal (BPS) is greater than or equal to a predetermined threshold value (b%) (S2). If the result of the S2 determination is “Yes,” the launch control unit (113) enters launch control. In the graph of Figure 4, time point T0 is the point of entry for oscillation control.

[0035] If the S2 judgment result is “No,” the S2 step can be continuously repeated to monitor whether to enter.

[0036] The oscillation controller (113) transmits a signal (PCS) to the power transmission control unit (114) in synchronization with the entry into oscillation control to indicate the entry into oscillation control. When the power transmission control unit (114) receives the signal (PCS), it can transmit a power signal (PS) instructing the power transmission device (41, 42) to connect the power. The power transmission device (41, 42) operates and connects according to the power signal (PS) (S3). Then, motor 1 (10), motor 2 (20), and motor 3 (30) are all directly connected. This is called the “direct connection state.”

[0037] The oscillation controller (113) transmits a signal (BCS) to the brake control unit (115) in synchronization with the entry into oscillation control to indicate the entry into oscillation control. When the brake control unit (115) receives the signal (BCS), it can transmit a brake control signal (BS) to the hydraulic cylinder (80) instructing the brake hydraulic control to stop. The hydraulic cylinder (80) stops the brake hydraulic control according to the brake control signal (BS) (S4). Then, since the hydraulic pressure applied to the brakes (81-84) is constant, the braking force applied to the front wheels (61, 62) and rear wheels (71, 72) can be maintained constant.

[0038] The oscillation controller (113) signals the entry into oscillation control by transmitting a signal (MCS1) to the motor control unit (116) to indicate the entry into oscillation control in synchronization with the entry into oscillation control. When the motor control unit (116) receives the signal (MCS1), it generates signals (MS1, MS2) to control the sum of the torques of motor 1 (10) and motor 2 (20) to a predetermined positive torque, generates a signal (MS3) to regenerate motor 3 (30) to a predetermined negative torque, and transmits the signals (MS1-MS3) to motor 1-motor 3 (10, 20, 30) (S5). The motor control unit (116) can receive torque detection signals (TS1, TS2, TS3) indicating the torque of motor 1 (10), motor 2 (20), and motor 3 (30) from each of motor 1 (10), motor 2 (20), and motor 3 (30).

[0039] For example, a 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 a predetermined negative torque may be -6000 Nm. That is, when entering oscillation control according to one embodiment, the power transmission device (41, 42) is connected, so that a direct connection state is formed where all motors 1 and 3 (10, 20, 30) are connected, and motors 1 (10) and 2 (20) operate at the maximum torque required for oscillation, and motor 3 (30) regenerates the torque provided from motors 1 (10) and 2 (20) to create a stopping condition for the electric vehicle (1). According to the regenerative control, the power conversion unit (93) can convert the power supplied from motor 3 (30) to charge the battery (95).

[0040] Conventionally, in launch control, the vehicle is brought to a stop using hydraulic pressure, and the motor operates in advance at the maximum torque capable of generating launch. However, since there is a limit to the hydraulic pressure, there is a limit to how long the vehicle can be kept stationary. Consequently, there is also a limit to the maximum torque the motor can generate in launch control. In other words, there is a limit to the launch capability.

[0041] In contrast, in the present invention, the brake hydraulic pressure is maintained at a constant level, and by using one of the three motors (motor 3) for regenerative braking, the remaining two motors (motor 1 and motor 2) can be controlled to maximum torque.

[0042] 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 oscillation controller (113).

[0043] As a result of the S6 judgment, the brake pedal detection signal (BPS) is 0%, and the oscillation controller (113) transmits a signal (MCS2) instructing the motor control unit (116) to start oscillation. The motor control unit (116) generates a signal (MS3) that increases the torque of motor 2 (20) to the maximum slope according to the signal (MCS2) and transmits it to motor 3 (30) (S7). In the graph of FIG. 4, time point T1 is the time point for the start of oscillation.

[0044] The motor control unit (116) determines whether the torque of the motor 3 (30) has reached a maximum value (S8).

[0045] When the torque of motor 3 (30) reaches its maximum value as a result of the judgment of S8, the motor control unit (116) performs normal control (S9). Normal control refers to the motor control operation after the oscillation control has ended. Under normal control conditions, the brake hydraulic pressure is controlled according to the brake pedal. In the graph of FIG. 4, time point T2 is the time when the torque of motor 3 (30) reaches its maximum value.

[0046] If, as a result of the judgment of S8, the torque of motor 3 (30) has not reached the maximum value, the motor control unit (116) maintains a control signal (MS3) that increases the torque of motor 3 (30) to the maximum slope.

[0047] In this way, even when in a standby state for launch, the torque energy of motor 1 (10) and motor 3 (30) is recovered through motor 3 (30), and the rate of change of torque output from motor 1-motor 3 (10, 20, 30) is significantly faster than the existing brake hydraulic conditions, so the launch capability is improved.

[0048] FIG. 5 is a graph comparing the launch capability of an electric vehicle according to one embodiment with that of a conventional one.

[0049] The slope of the brake hydraulic pressure rise during acceleration in a conventional vehicle shown in Fig. 5 is 2200 Nm / s. As indicated by the thick solid line in Fig. 5, the motor torque during acceleration control in a conventional vehicle is controlled to be below the brake hydraulic pressure.

[0050] In contrast, the present invention utilizes the regenerative braking of motor 2 to utilize the torque of the motor beyond the brake hydraulic pressure during launch. As shown in FIG. 5, the torque rise slope of motor 2 is 4000 Nm / s.

[0051] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modified and improved forms by those skilled in the art to which the present invention pertains also fall within the scope of the present invention. Explanation of the symbols

[0052] 1: Electric vehicle 10, 20, 30: Motor 1-3 41, 42: Power transmission device

Claims

Claim 1 An electric vehicle comprising: a first motor for driving the front wheels; a second motor for driving the rear wheels; a third motor connected to the first motor and the second motor in the oscillation control; a first power transmission device connecting the first motor and the third motor in the oscillation control; and a second power transmission device connecting the second motor and the third motor in the oscillation control. Claim 2 In claim 1, the electric vehicle enters the launch control when the accelerator pedal and the brake pedal of the electric vehicle are pressed simultaneously. Claim 3 An electric vehicle according to paragraph 2, wherein while the accelerator pedal and the brake pedal are pressed simultaneously, the third motor regenerates the torque of the first motor and the second motor. Claim 4 An electric vehicle according to paragraph 3, further comprising a battery charged by regenerative control of the third motor. Claim 5 In paragraph 3, an electric vehicle in which, after entering the above-mentioned oscillation control, if the above-mentioned brake pedal is not pressed, the torque of the above-mentioned third motor rises at a predetermined slope. Claim 6 In claim 1, the electric vehicle in which the brake hydraulic pressure of the electric vehicle is maintained at a constant level in the above-mentioned oscillation control. Claim 7 A method for controlling the launch of an electric vehicle comprising a first motor driving a front wheel, a second motor driving a rear wheel, and a third motor located between the first motor and the second motor, the method comprising: a step of simultaneously pressing an accelerator pedal and a brake pedal; a step of connecting the first motor, the second motor, and the third motor when the accelerator pedal and the brake pedal are simultaneously pressed by a first power transmission device and a second power transmission device; a step of regeneratively controlling the torque of the first motor and the second motor by the third motor; and a step of increasing the torque of the third motor at a predetermined slope when the brake pedal is not pressed. Claim 8 A oscillation control method according to claim 7, further comprising the step of charging a battery by regenerative control of the third motor. Claim 9 A method for controlling a oscillation according to claim 7, wherein, in the above-mentioned oscillation control, the brake hydraulic pressure of the electric vehicle is maintained at a constant level. Claim 10 An electric vehicle comprising: 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; a power transmission control unit that controls the first power transmission device and the second power transmission device to connect all of the first to third motors in the oscillation control; and an oscillation control unit that detects the entry into the oscillation control and notifies the power transmission control unit of the entry into the oscillation control. Claim 11 In claim 10, the above-mentioned oscillation control unit detects the entry into the oscillation control when the accelerator pedal and the brake pedal of the electric vehicle are pressed simultaneously. Claim 12 An electric vehicle according to claim 11, further comprising a motor control unit that controls 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 pressed simultaneously. Claim 13 In claim 12, the motor control unit controls the third motor such that when the brake pedal is not pressed after entering the oscillation control, the torque of the third motor rises at a predetermined slope. Claim 14 An electric vehicle according to claim 10, further comprising a brake control unit that receives the entry of the oscillation control from the oscillation control unit and controls the brake hydraulic pressure of the electric vehicle at a constant level.

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