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KR-102962208-B1 - SYSTEM FOR CONTROLLING MOTORS OF VEHICLE HAVING ELECTRIC-AXLE AND METHOD THEREOF

KR102962208B1KR 102962208 B1KR102962208 B1KR 102962208B1KR-102962208-B1

Abstract

The present invention aims to provide a motor control system and method for a commercial vehicle having an electrified axle, wherein in a low-power demand section, the torque of a first motor included in the rear-wheel electrified axle is controlled to follow a target torque, while simultaneously controlling the torque of a second motor included in the rear-wheel electrified axle to a level that compensates for the torque error of the first motor, and in a high-power demand section, the torques of the first motor and the second motor included in the rear-wheel electrified axle are controlled with a constant duty ratio that alternates with each other, thereby not only satisfying the driver's requested torque but also increasing the maximum torque usage time of the first motor and the second motor.

Inventors

  • 오준

Assignees

  • 현대자동차주식회사
  • 기아 주식회사

Dates

Publication Date
20260508
Application Date
20210413

Claims (12)

  1. A first motor and a second motor included in the rear-wheel electrified axle; Accelerator pedal position sensor for detecting the degree of accelerator pedal depressure; A wheel speed sensor that detects changes in wheel speed; and A controller that determines the driver's requested torque based on the detection signals of the accelerator pedal position sensor and the wheel speed sensor, controls the torque of the first motor to follow a target torque to satisfy the driver's requested torque, while simultaneously controlling the torque of the second motor to a level that compensates for the torque error of the first motor, or controls the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other; Composed of including, A motor control system for a commercial vehicle having an electrified axle, characterized in that the above controller is configured to determine the maximum torque cycle of the first motor and the second motor as the time before the temperature of each motor reaches the maximum reference temperature when controlling the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other.
  2. In claim 1, The above controller is: A vehicle controller that determines the driver's requested torque based on the detection signal of the accelerator pedal position sensor and then applies a motor torque command to the motor controller to satisfy the driver's requested torque; A motor controller that, based on the above motor torque command, controls the torque of the first motor to follow a target torque while simultaneously controlling the torque of the second motor to a level that compensates for the torque error of the first motor, or controls the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other; A motor control system for a commercial vehicle having an electrified axle characterized by being composed of
  3. In claim 1, The above controller is, A motor control system for a commercial vehicle having an electrified axle, characterized by being configured to control the torque of the first motor to follow a target torque to satisfy the driver's requested torque in a low-power demand range, while simultaneously controlling the torque of the second motor to a level that compensates for the torque error of the first motor.
  4. In claim 1, The above controller is, A motor control system for a commercial vehicle having an electrified axle, characterized by being configured to control the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other in a high-output demand range.
  5. In claim 4, A motor control system for a commercial vehicle having an electrified axle, characterized in that the above controller controls the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other, such that the sum of the torque of the first motor and the torque of the second motor becomes the driver's requested torque.
  6. In claim 1, A motor control system for a commercial vehicle having an electrified axle, characterized in that, when the above-described rear-wheel electrified axle is composed of a rear-wheel first electrified axle including the above-described first motor and a rear-wheel second electrified axle including the above-described second motor, the above-described first motor is adopted as a high-precision model with greater precision than the second motor to output a target torque to satisfy the driver's requested torque, and the above-described second motor is adopted as a low-precision model with lower precision than the first motor to output a torque that compensates for the torque error of the first motor.
  7. In claim 1, A motor control system for a commercial vehicle having an electrified axle, characterized in that, when the above-described rear-wheel electrified axle is composed of a single electrified axle including the above-described first motor and second motor, the first motor is adopted as a high-precision model with greater precision than the second motor to output a target torque to satisfy the driver's requested torque, and the second motor is adopted as a low-precision model with lower precision than the first motor to output a torque that compensates for the torque error of the first motor.
  8. A step of detecting the degree of accelerator pedal depressure using an accelerator pedal position sensor; A step of detecting a change in wheel speed from a wheel speed sensor; A step of determining the driver's requested torque in the controller based on the detection signals of the accelerator pedal position sensor and the wheel speed sensor; A step of controlling the torque of a first motor included in a rear-wheel electrified axle to follow a target torque to satisfy the driver's demand torque according to the magnitude of the determined driver's demand torque, while simultaneously controlling the torque of a second motor included in the rear-wheel electrified axle to a level that compensates for the torque error of the first motor, or controlling the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other; Includes, A motor control method for a commercial vehicle having an electrified axle, characterized in that when controlling the torque of the first motor and the torque of the second motor with a constant duty cycle that alternates with each other, the maximum torque period of the first motor and the second motor is determined as the time before the temperature of each motor reaches the maximum reference temperature.
  9. In claim 8, A motor control method for a commercial vehicle having an electrified axle, characterized in that when the magnitude of the driver's demanded torque is determined to be at a level requiring low output of the motor, the torque of the first motor included in the rear-wheel electrified axle is controlled to follow a target torque to satisfy the driver's demanded torque, while the torque of the second motor included in the rear-wheel electrified axle is controlled to a level that compensates for the torque error of the first motor.
  10. In claim 8, A motor control method for a commercial vehicle having an electrified axle, characterized in that when the magnitude of the driver's requested torque is determined to be at a level requiring high output of the motor, a step of controlling the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other is performed.
  11. In claim 10, A motor control method for a commercial vehicle having an electrified axle, characterized by controlling the torque of the first motor and the torque of the second motor with a constant duty ratio that alternates with each other, such that the sum of the torque of the first motor and the torque of the second motor becomes the driver's requested torque.
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Description

System for controlling motors of a commercial vehicle having an electric axle and method thereof The present invention relates to a motor control system and method for a commercial vehicle having an electrified axle, and more specifically, to a motor control system and method for a commercial vehicle having an electrified axle in which two or more motors mounted on the electrified axle are adopted with different specifications to accurately satisfy the driver's required torque while simultaneously realizing cost reduction of the electrified axle. With the launch of eco-friendly passenger vehicles such as electric vehicles and hydrogen fuel cell vehicles, pure electric trucks or hydrogen fuel cell trucks equipped with electric axle assemblies are being developed as a type of eco-friendly commercial vehicle. Figure 1 attached is a schematic diagram illustrating the powertrain of a hydrogen fuel cell truck among commercial vehicles having an electrified axle. As illustrated in FIG. 1, a hydrogen fuel cell truck among commercial vehicles having an electrified axle includes a fuel cell (30) that generates electric energy and a battery (40) in which the electric energy generated from the fuel cell (30) is charged. In addition, the hydrogen fuel cell truck has a structure in which, in addition to the front wheel positioned at the front, a pair of rear wheels serving as driving wheels are arranged at the rear, and among the pair of rear wheels, a first electrified axle (10) is mounted on the front rear wheel and a second electrified axle (20) is mounted on the rear rear wheel. The above-mentioned rear first electric axle (10) may be configured to include an axle housing, a first motor (11) mounted within the axle housing and driven by electrical energy from a fuel cell (30) or a battery (40), a first axle shaft (12) connected to the output shaft of the first motor (11), and a first wheel (13) mounted on both ends of the first axle shaft (12). The above-mentioned second electric axle (20) may also be configured to include an axle housing, a second motor (21) mounted within the axle housing and driven by electrical energy from a fuel cell (30) or a battery (40), a second axle shaft (22) connected to the output shaft of the second motor (21), and second wheels (23) mounted on both ends of the second axle shaft (22). At this time, the first motor (11) and the second motor (21) are adopted with the same specifications and have the same capacity. For example, as shown in FIG. 2a, the first motor (11) and the second motor (21) are each adopted as high-performance, high-priced models that output a maximum torque of 1400 Nm. Meanwhile, depending on the type of truck, the hydrogen fuel cell truck may have a structure in which, in addition to the front wheels positioned at the front, one rear wheel serving as a driving wheel is arranged at the rear, and the one rear wheel serving as a driving wheel may be equipped with an electrified axle having a first motor (11) and a second motor (21) that output torque to a single axle shaft, and the first motor (12) and the second motor (21) of the electrified axle are also adopted as high-performance, high-priced models that each output a maximum torque of 1400 Nm, as shown in FIG. 2b. Here, referring to FIGS. 3 and 4, which include examples of torque control for the first and second motors adopted as high-performance, high-cost models, the following applies. When the vehicle controller, which is the higher-level controller, determines the driver's requested torque based on the amount the driver presses the accelerator pedal and issues a torque command corresponding to the determined driver's requested torque to the motor controller, the motor controller executes torque control for the first motor and the second motor. As an example of torque control for the first motor and the second motor, the torque of the first motor and the torque of the second motor are distributed and controlled in equal proportions so that the driver's requested torque can be satisfied by the sum of the torque output from the first motor and the torque output from the second motor. For example, as shown in FIG. 3, if the driver's requested torque in the low power demand range is 200 Nm, the torque of the first motor and the second motor is controlled to 100 Nm each, and if the driver's requested torque in the high power demand range is 2000 Nm, the torque of the first motor and the second motor is controlled to 1000 Nm each. As another example of torque control for the first motor and the second motor, the torque of the first motor and the torque of the second motor are controlled at different ratios or equal ratios so that the driver's requested torque can be satisfied by the torque of the first motor or the torque of the second motor, or by the sum of the torque of the first motor and the torque of the second motor. For example, as shown in FIG. 4, if the driver's requested torque in the low power demand range