Vehicle Controls

Abstract

The present invention provides a vehicle control device capable of improving the marketability of an electric vehicle. A vehicle control device according to one embodiment of the present invention includes a driving control unit that drives a motor to control the driving force of the electric vehicle when the electric vehicle having a battery and a motor is running. The driving control unit changes a carrier frequency when driving the motor according to a gear ratio set according to a gear shift operation performed by a driver of the electric vehicle.

Description

Technical Field

[0001] The present invention relates to a vehicle control device for controlling the operation of an electric vehicle. Background Art

[0002] In recent years, hybrid electric vehicles (HEV) that effectively improve the fuel consumption rate (fuel efficiency) of vehicles by using both an engine and an electric motor have been widely used in practice. In addition, electric vehicles (EV) that use only electric motors as a driving force source and do not emit exhaust gas have also been used in practice. For example, Patent Document 1 discloses various controls in such electric vehicles such as HEVs and EVs.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-117876 Summary of the invention

[0006] Technical issues

[0007] However, such electric vehicles are generally required to have improved marketability. It is desirable to provide a vehicle control device that can improve the marketability of electric vehicles.

[0008] Technical Solution

[0009] A vehicle control device according to an embodiment of the present invention includes a driving control unit that drives a motor to control the driving force of an electric vehicle having a battery and a motor when the electric vehicle is running. The driving control unit changes a carrier frequency when driving the motor according to a gear ratio set according to a shift operation performed by a driver of the electric vehicle.

[0010] Technical Effects

[0011] According to the vehicle control device of one embodiment of the present invention, the marketability of an electric vehicle can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a block diagram showing a schematic configuration example of an electric vehicle including a vehicle control device according to an embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram showing an example of a carrier synchronization number table according to an implementation mode.

[0014] Figure 3 This is a schematic diagram showing an example of a carrier frequency setting process according to the embodiment.

[0015] Explanation of symbols

[0016] 1…Electric vehicle (EV); 10a…Motor; 10b…Rotation angle sensor; 11…Battery; 121…Vehicle speed sensor; 122…Acceleration sensor; 13…Shift operation unit; 141…Accelerator pedal sensor; 142…Brake pedal sensor; 15…Vehicle control unit; 151…Travel control unit; 151a…Motor control unit (inverter); 151b…Switch control unit; 151c…Carrier frequency setting unit; 152…Battery control unit; V…Vehicle speed; a…Acceleration; θm…Rotation angle; Nr…Number of revolutions; Nmin…Minimum threshold; Ns…Number of gear steps; Rg…Speed ​​ratio; Ii…Suppression information; SW…Switch element; fc…Carrier frequency; Nc…Carrier synchronization number; Tb…Carrier synchronization number table DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the description will be given in the following order.

[0018] 1. Embodiment (Example of setting process of carrier frequency when driving motor of electric vehicle)

[0019] 2. Modifications

[0020] <1. Implementation Method>

[0021] [Overview of the composition]

[0022] Figure 1 This is a block diagram showing a schematic configuration example of an electric vehicle 1 including a vehicle control device (a vehicle control unit 15 described later) according to an embodiment of the present invention.

[0023] like Figure 1 As shown, the electric vehicle 1 mainly includes a motor 10a (electric motor), a rotation angle sensor 10b, a battery 11, a vehicle speed sensor 121, an acceleration sensor 122, a shift operation unit 13, an accelerator pedal sensor 141, a brake pedal sensor 142 and a vehicle control unit 15.

[0024] (A. Motor 10a, rotation angle sensor 10b)

[0025] The motor 10a is provided as a driving force source in the electric vehicle 1. That is, the electric vehicle 1 is configured as an electric vehicle (EV) having the motor 10a as a driving force source.

[0026] The rotation angle sensor 10b is, for example, mounted on the motor 10a and is a sensor that outputs the rotation angle θm of the motor 10a to the vehicle control unit 15 (see Figure 1 ) Such a rotation angle sensor 10b is constituted by using, for example, a resolver type rotation angle sensor.

[0027] It should be noted that the rotation angle θm of the motor 10a thus detected is, for example, Figure 1 The information in brackets is converted into the number of revolutions Nr of the motor 10a in the vehicle control unit 15, for example. Then, the information of the number of revolutions Nr obtained in this way is output to the travel control unit 151 (carrier frequency setting unit 151c) described later in the vehicle control unit 15 (see Figure 1 ).

[0028] (B. Battery 11)

[0029] The battery 11 is used to store power used in the electric vehicle 1 and is composed of various secondary batteries such as lithium ion batteries. In addition to power (charged power) obtained by charging from outside the electric vehicle 1, the battery 11 also stores regenerative power provided by the motor 10a, for example.

[0030] (C. Vehicle speed sensor 121, acceleration sensor 122)

[0031] The vehicle speed sensor 121 is a sensor for detecting the speed (vehicle speed V) of the electric vehicle 1 when it is traveling. Figure 1 As shown, the vehicle speed V detected by the vehicle speed sensor 121 is output to the vehicle control unit 15 (such as the travel control unit 151 described later).

[0032] The acceleration sensor 122 is a sensor for detecting the acceleration a of the electric vehicle 1 when it is traveling. Figure 1 As shown, the acceleration a detected by the acceleration sensor 122 is output to the vehicle control unit 15 (such as the travel control unit 151 described later).

[0033] (D. Shift operation unit 13)

[0034] The shift operation unit 13 is an operation unit for the driver of the electric vehicle 1 to perform a shift operation, and is composed of a shift lever or the like. Figure 1 As shown in FIG. 1 , information set according to the shift operation of the shift operation unit 13 is output to the travel control unit 151 (carrier frequency setting unit 151c) described later in the vehicle control unit 15. Examples of such information include the number of gear steps Ns (“1st gear”, “2nd gear”, “3rd gear”, etc.) set according to the shift operation, information on the speed ratio Rg corresponding to the number of gear steps Ns, and suppression information Ii (see FIG. 1 ). Figure 1 ). It should be noted that the suppression information Ii is information indicating whether the setting mode of the speed ratio Rg is set to the manual mode or the automatic mode, and is information indicating whether the so-called "M" gear stage (manual mode) is set.

[0035] Here, the above-mentioned number of gear steps Ns (speed ratio Rg) corresponds to a specific example of "speed ratio set according to shift operation" in the present invention.

[0036] (E. Accelerator pedal sensor 141, brake pedal sensor 142)

[0037] The accelerator pedal sensor 141 is a sensor for detecting the amount of depression (accelerator opening) of an accelerator pedal (not shown) by the driver of the electric vehicle 1. The brake pedal sensor 142 is a sensor for detecting the amount of depression (brake stroke) of a brake pedal (not shown) by the driver of the electric vehicle 1.

[0038] Thus, the accelerator opening detected by the accelerator pedal sensor 141 and the brake stroke detected by the brake pedal sensor 142 are respectively as follows: Figure 1 The signal is output to the vehicle control unit 15 (such as the travel control unit 151 described later).

[0039] (F. Vehicle control unit 15)

[0040] The vehicle control unit 15 is a part that controls various actions or performs various calculations in the electric vehicle 1. Specifically, the vehicle control unit 15 is configured to include a microprocessor that performs calculations, a ROM (Read Only Memory) that stores programs for the microprocessor to execute various processes, a RAM (Random Access Memory) that stores various data such as calculation results, a backup RAM that stores the stored content, and an input / output I / F (Interface).

[0041] exist Figure 1 In the illustrated example, such a vehicle control unit 15 includes a travel control unit 151 and a battery control unit 152 .

[0042] Here, the vehicle control unit 15 corresponds to a specific example of the “vehicle control device” in the present invention.

[0043] (F-1. Travel Control Unit 151)

[0044] The travel control unit 151 is used to control the travel operation of the electric vehicle 1 and perform overall control related to the travel of the electric vehicle 1. Figure 1 In the example shown, the motor control unit 151a is provided, and when the electric vehicle 1 is running, the motor 10a is driven to control the driving force of the electric vehicle 1. Figure 1 In the example shown, a switch control unit 151b and a carrier frequency setting unit 151c are further provided.

[0045] The motor control unit 151a is used to drive the motor 10a to control various operations. In this example, the motor control unit 151a is configured using an inverter (see Figure 1 ). Specifically, the motor control unit 151a controls, for example, the driving action of the wheels of the electric vehicle 1 performed by the motor 10a, the regeneration action in the motor 10a, etc. Figure 1 The illustrated embodiment includes a plurality of switch elements SW constituted by IGBTs (Insulated Gate Bipolar Transistors) and the like.

[0046] The switch control unit 151b is used to control the switching between the on state and the off state of each switch element SW in the inverter (on / off control). Specifically, the switch control unit 151b performs pulse width modulation (PWM: Pulse Width Modulation) control when performing the on / off control of each switch element SW. In addition, such PWM control is performed based on the carrier frequency fc provided by the carrier frequency setting unit 151c described later (see Figure 1 ).

[0047] It should be noted that, when the on / off control of each switching element SW is performed, various controls are performed in detail, for example, as described below. That is, first, based on the torque command corresponding to the accelerator opening detected by the accelerator pedal sensor 141 and the brake stroke detected by the brake pedal sensor 142, the voltage command (Vu, Vv, Vw) is controlled in a manner following an arbitrary current command (id, iq). Then, by comparing the voltage command (Vu, Vv, Vw) with a carrier (carrier frequency fc described below), a gate command (control signal) for on / off control of each switching element SW in the inverter is generated.

[0048] The carrier frequency setting unit 151c is used to set the carrier frequency fc, which is the frequency that determines the cycle of the above-mentioned PWM control. Figure 1 As shown, the carrier frequency setting unit 151c sets the carrier frequency fc based on the gear level number Ns (speed ratio Rg) and suppression information Ii provided from the above-mentioned shift operating unit 13, and the number of revolutions Nr of the motor 10a, and the number of revolutions Nr of the motor 10a is obtained based on the rotation angle θm provided from the above-mentioned rotation angle sensor 10b.

[0049] In addition, at this time, the carrier frequency setting unit 151c changes the carrier frequency fc when driving such a motor 10a according to the gear stage number Ns (speed ratio Rg) set according to the gear shift operation performed by the driver of the electric vehicle 1 as described above. Further, in the present embodiment, the carrier frequency setting unit 151c changes the carrier frequency fc according to the gear stage number Ns (speed ratio Rg) and the number of revolutions Nr of the motor 10a described above.

[0050] It should be noted that the details of the carrier frequency fc setting process performed by the carrier frequency setting unit 151c will be described later ( Figure 2 and Figure 3 ).

[0051] (F-2. Battery control unit 152)

[0052] The battery control unit 152 is used to perform various controls (charging control, etc.) on the battery 11 (see Figure 1 ).

[0053] [Actions and functions / effects]

[0054] Next, the operation and effects of the electric vehicle 1 according to the present embodiment will be described.

[0055] (A. Vehicle Control Processing of the Present Embodiment)

[0056] The following, except Figure 1 In addition, refer to Figure 2 and Figure 3 An example of the control process (such as the process of setting the carrier frequency fc described above) in the electric vehicle 1 according to the present embodiment will be described in detail.

[0057] (A-1. Regarding electromagnetic noise generated from the motor 10a)

[0058] First, as described above, in the motor 10a (electric motor) driven by PWM control, electromagnetic noise is generated according to the on / off frequency (carrier frequency fc) of the switching element SW in the motor control unit 151a (inverter). Specifically, for example, in the motor winding of the motor 10a, a current ripple corresponding to the carrier frequency fc is generated. In addition, the sound (electromagnetic noise generated from the motor 10a) changes according to the carrier frequency fc.

[0059] (A-2. Details of Carrier Frequency fc Setting Process)

[0060] Here, in the electric vehicle 1 of the present embodiment, the vehicle control unit 15 (the carrier frequency setting unit 151c in the travel control unit 151) performs such a carrier frequency fc setting process as described below, thereby changing the electromagnetic noise generated from the motor 10a.

[0061] Figure 2 Schematically shows an example of a carrier synchronization number table Tb used in the setting process of the carrier frequency fc of this embodiment. In the carrier synchronization number table Tb, the correspondence between the above-mentioned gear stage number Ns (speed ratio Rg) and the carrier synchronization number Nc is shown. The carrier synchronization number Nc is a parameter that becomes the basis for setting the carrier frequency fc. It should be noted that in this Figure 2 In the example of the carrier synchronization number table Tb shown, as the number of gear stages Ns increases, the carrier synchronization number Nc gradually decreases.

[0062] also, Figure 3 Schematically shows an example of the setting process of the carrier frequency fc of this embodiment. Figure 3 , an example of the correspondence between the number of revolutions Nr of the motor 10a and the number of gear stages Ns (speed ratio Rg) and the set carrier frequency fc is shown. Figure 3 The embodiment shown is an example in which, when the speed Nr = 3000 [rpm], the gear level number Ns changes from the "1st gear" state to the "2nd gear" state, when the speed Nr = 5000 [rpm], the gear level number Ns changes from the "2nd gear" state to the "3rd gear" state, and when the speed Nr = 8000 [rpm], the gear level number Ns changes from the "3rd gear" state to the "4th gear" state.

[0063] Here, the carrier frequency setting unit 151c changes the carrier frequency fc according to the gear step number Ns (speed ratio Rg) set according to the shift operation performed by the driver of the electric vehicle 1 as described above (see Figure 3 Specifically, in this example, the carrier frequency setting unit 151c controls the carrier frequency fc so that it decreases as the speed ratio Rg becomes lower (as the number of gear steps Ns increases from "1st gear" to "4th gear"). In this way, when the driver performs a gear shift operation, the carrier frequency fc is changed in a large switching manner, thereby generating a sense of change in the sound (electromagnetic noise generated by the motor 10a) as if a gear shift has occurred.

[0064] At this time, the carrier frequency setting unit 151c changes the carrier frequency fc according to the gear ratio Rg only when the setting mode of the gear ratio Rg is set to the manual mode (in the manual mode) according to the shift operation performed by the driver (see Figure 3)。That is, the setting process of the carrier frequency fc corresponding to the gear ratio Rg is performed only when, for example, the state set to the "M" gear range (manual mode) is shown in the above-described suppression information Ii. This is because in normal control (state other than the "M" gear range: automatic mode), it is preferable to set the carrier frequency fc in consideration of the system efficiency etc. in the electric vehicle 1 rather than the gear shift operation performed by the driver.

[0065] In addition, as described above, while the carrier frequency setting unit 151c changes the carrier frequency fc according to such a gear ratio Rg (number of gear steps Ns), it also changes the carrier frequency fc according to the rotational speed Nr of the motor 10a (refer to Figure 3 the arrow P2 in). Specifically, in this example, the carrier frequency setting unit 151c controls the carrier frequency fc to increase as the rotational speed Nr of the motor 10a increases (linearly increases in the Figure 3 example). Thus, when the number of gear steps Ns (gear ratio Rg) is fixed by the gear shift operation performed by the driver, according to the change (increase or decrease) in the rotational speed Nr of the motor 10a, the carrier frequency fc also changes (increases or decreases), and the electromagnetic noise generated from the motor 10a fluctuates.

[0066] At this time, the carrier frequency setting unit 151c changes the carrier frequency fc according to the rotational speed Nr only when the rotational speed Nr of the motor 10a is equal to or higher than a predetermined minimum threshold Nmin (in the Figure 3 example, when Nr ≥ 500 [rpm]). This is because when the rotational speed Nr is very low (when Nr < Nmin), it is difficult to perform synchronous PWM control, and the controllability may deteriorate. It should be noted that when the rotational speed Nr is very low like this, it is preferable to perform asynchronous PWM control.

[0067] (B. Function / Effect)

[0068] Thus, in the electric vehicle 1 of the present embodiment, the traveling control unit 151 (carrier frequency setting unit 151c) changes the carrier frequency fc when driving the drive motor 10a according to the gear ratio Rg (number of gear steps Ns) set according to the gear shift operation performed by the driver of the electric vehicle 1. Thereby, in the electric vehicle 1 having the motor 10a as a driving force source, it is possible to generate a sense of change in the sound (electromagnetic noise generated from the motor 10a) corresponding to the gear shift operation performed by the driver. Therefore, in the present embodiment, the marketability of the electric vehicle 1 can be improved.

[0069] In addition, in the present embodiment, the travel control unit 151 changes the carrier frequency fc according to the above-mentioned speed ratio Rg (number of gear stages Ns), and also changes the carrier frequency fc according to the number of revolutions Nr of the motor 10a, so as to be described below. That is, the sense of change of the electromagnetic noise generated from the motor 10a can be generated not only in accordance with the shift operation performed by the driver, but also in accordance with the number of revolutions Nr of the motor. As a result, in the present embodiment, the marketability of the electric vehicle 1 can be further improved.

[0070] <2. Modifications>

[0071] As mentioned above, although embodiment was given and this invention was demonstrated, this invention is not limited to this embodiment, Various deformation|transformation is possible.

[0072] For example, the configuration (form, shape, arrangement, number, etc.) of each component in the electric vehicle 1 is not limited to the contents described in the above embodiment. That is, the configuration of each component may be other forms, shapes, arrangements, numbers, etc. In addition, the values, ranges, size relationships, etc. of the various parameters described in the above embodiment are not limited to those described in the above embodiment, but may be other values, ranges, size relationships, etc.

[0073] Specifically, for example, in the above embodiment, the case where one motor (motor 10a) is provided in the electric vehicle 1 is described as an example, but the present invention is not limited to this example. That is, for example, a plurality of (two or more) motors may be provided in the electric vehicle 1. In addition, in the above embodiment, the electric vehicle 1 constituted by EV is described as an example, but the present invention is not limited to this example, and for example, the present invention may also be applied to an electric vehicle constituted by HEV (a hybrid vehicle having an engine and a motor as a driving force source).

[0074] In addition, in the above-mentioned embodiment, specific examples are given to illustrate the control process of the electric vehicle 1, but it is not limited to these specific examples. That is, other methods can also be used to perform the control process of the electric vehicle 1, etc. Specifically, for example, various methods for driving control in the electric vehicle 1 (methods for setting the carrier frequency, etc.) are not limited to the methods described in the above-mentioned embodiment. In detail, in the above-mentioned embodiment, a method for changing the carrier frequency fc according to the number of revolutions Nr of the motor 10a together with the speed ratio Rg (number of gear stages Ns) is described, but it is not limited to this method. That is, for example, depending on the situation, the carrier frequency fc can also be changed only according to the speed ratio Rg (number of gear stages Ns). In addition, such a method for setting the carrier frequency, etc. is not limited to the case of a stepped transmission, for example, it can also be applied in the case of a continuously variable transmission (CVT: Continuously Variable Transmission).

[0075] Furthermore, the series of processes described in the above embodiments can be performed by hardware (circuit) or by software (program). In the case of being performed by software, the software is composed of a program group for causing the computer to perform each function. For example, each program can be pre-installed in the above computer for use, or can be installed from a network or storage medium to the above computer for use.

[0076] In addition, the various examples described so far may be applied in any combination.

[0077] It should be noted that the effects described in this specification are merely exemplary and are not limiting, and other effects may also be present.

Claims

1. A vehicle control device, characterized in that: have: a travel control unit that drives the motor to control the driving force of the electric vehicle when the electric vehicle having a battery and a motor travels, The travel control unit changes a carrier frequency when driving the motor according to a speed ratio, the speed ratio being set in accordance with a shift operation performed by a driver of the electric vehicle. When the speed ratio setting mode is set to manual mode, the carrier frequency is changed according to the speed of the motor only when the speed of the motor is above a predetermined threshold value, and the carrier frequency is not changed if the speed of the motor is lower than the predetermined threshold value.

2. The vehicle control device according to claim 1, characterized in that: The travel control unit controls the carrier frequency so as to decrease as the speed ratio becomes lower.

3. The vehicle control device according to claim 1, characterized in that: The travel control unit controls the carrier frequency so as to increase as the number of revolutions of the motor increases.

4. The vehicle control device according to claim 1, characterized in that: The travel control unit changes the carrier frequency according to the speed ratio only when the setting mode of the speed ratio is set to the manual mode according to the shift operation.

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