KR101417666B1 - Method for removing motor torque ripple of electric vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a vibration control method of an electric vehicle using a brake acceleration sensor, and more particularly, to a vibration control method of an electric vehicle using a brake acceleration sensor, And more particularly, to a vibration control method for an electric vehicle.
That is, the present invention relates to a brake control system for a vehicle that extracts a vibration component from a detection signal of a brake acceleration sensor at a low-speed traveling of an electric vehicle, stores the vibration component in a memory for each rotor position, A vibration control method of an electric vehicle using a brake acceleration sensor capable of improving a reduction performance of a motor vibration at low speed by compensating a torque to a motor command torque.

Description

TECHNICAL FIELD [0001] The present invention relates to a vibration control method for an electric vehicle using a brake acceleration sensor,

The present invention relates to a vibration control method for an electric vehicle using a brake acceleration sensor, and more particularly, to a vibration control method for an electric vehicle that uses a brake acceleration sensor to reduce a motor torque ripple To a vibration control method for an electric vehicle using a brake acceleration sensor.

Generally, an electric vehicle is divided into a pure electric vehicle that uses only a high-voltage battery as a power source and a hybrid electric vehicle that uses engine power as an auxiliary power without using engine power at all.

The power transmission structure and operation of the electric vehicle are briefly described as follows: an inverter that converts DC power output from a high-voltage battery into AC power; a motor that generates AC power from AC power supplied from the inverter; And a speed reducer which is connected and connected to the driving wheel so as to transmit the rotational force to the driving wheel side. Power from the output shaft of the speed reducer is transmitted to the driving wheel to drive the electric vehicle.

In the case of an electric vehicle in which the motor is directly connected to the driving wheel through a speed reducer, vehicle vibration occurs due to motor torque ripple generated when the motor is driven.

As a conventional vibration control method for reducing such motor torque ripple, a vibration component is extracted from a detection signal of a speed sensing sensor for detecting a motor speed (rpm) or a vehicle speed (rpm) A method of reducing vibration by utilizing it for compensation is widely used.

That is, a method is employed in which a vibration component is extracted from a motor speed or a vehicle speed (driving wheel speed) signal detected by a speed sensing sensor, and the vibration component is inversely compensated by a motor torque command.

However, since the speed sensor for detecting the motor speed by detecting the position of the rotor of the motor or sensing the rotation speed of the driving wheel is limited in its resolution, the motor speed or the driving speed of the driving wheel, There is a limitation in extracting the vibration component from the detection signal of the speed sensing sensor that detects the speed of the motor vehicle and the speed of the vehicle. Therefore, there is a problem in that the vibration due to the motor torque ripple can not be reduced at low speeds of the electric vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a brake acceleration sensor that extracts a vibration component from a detection signal of a brake acceleration sensor, And an object of the present invention is to provide a vibration control method for an electric vehicle using a brake acceleration sensor that can improve a reduction performance of a motor vibration at a low speed by compensating a compensation torque obtained by control (Iterative Learning Control) to a motor command torque.

According to an aspect of the present invention, there is provided a method for controlling a vehicle, comprising: extracting a vibration component of a motor torque from a deceleration detection signal of a vehicle and tire radius information; Storing the extracted vibration component in a memory for each rotor position of the motor; Performing repetitive learning control for compensating torque extraction based on stored vibration component data; Compensating the compensation torque obtained through the iterative learning control to the motor command torque; The present invention provides a vibration control method for an electric vehicle using a brake acceleration sensor.

The step of extracting the vibration component of the motor torque includes the steps of estimating the motor torque based on the deceleration detection signal of the brake acceleration sensor and the tire radius information, And passing through the path to extract a vibration component.

As a preferred embodiment of the present invention, the iterative learning control comprises the steps of: storing the vibration component e by the rotor position? In the first rotation period (i = 1) of the motor rotor; Once storing the compensation torque [ΔT _i (θ)] multiplied by the gain (Gain) is stored in each vibration component E position (θ) and; Previous rotation period (i) the rotor position (θ) by compensating the torque of [ΔT _i (θ)] and the vibration component [e _i (θ)], the vibration component of the next rotation cycle _{(i + 1) [e i} + 1 (&thetas;)&thetas;) by a gain; And a control unit.

Preferably, the gain is: in the previous rotation period (i) of the current rotor position (θ) the compensation torque [ΔT _i (θ)] parameter (α) for determining how much to reflect the computed at, before rotation period ( i) the current rotor vibration component generated in the position _{(θ) [e i (θ} )] and how you want to determine the variable (Γ), reflecting, then the rotation period (i + 1) are vibration components of the [e _{i + 1} (&thetas;)] to be reflected.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

According to the present invention, a vibration component of a motor torque is extracted from a detection signal (deceleration signal) of a brake acceleration sensor at the time of an electric vehicle running at a low speed, and the compensation torque obtained by performing the iterative learning control By compensating for the torque, it is possible to improve the performance of reducing the motor vibration when the electric vehicle is running at low speed (for example, when running at low speed or when decelerating).

1 is a torque diagram showing that motor torque ripple is generated periodically in accordance with a rotor position,
2 is a control block diagram showing a vibration control method of an electric vehicle using a brake acceleration sensor according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention extracts a vibration component from a motor torque estimated on the basis of a detection signal (deceleration) of a brake acceleration sensor and a radius of a tire in order to reduce vibration caused by motor torque ripple during low-speed driving of an electric vehicle, And the motor torque command is used to compensate the compensating torque obtained by performing the iterative learning control based on the motor torque command, thereby reducing the traveling vibration due to the motor torque ripple.

As shown in FIG. 1, the motor torque ripple is repeatedly displayed at intervals of 360 degrees according to the rotor angular position of the motor. The reason why motor torque ripple occurs is a parameter at the time of motor design, .

Therefore, torque ripple according to the parameter at the time of designing the motor occurs periodically, and the torque ripple due to the current sensor offset also appears periodically as long as the offset value is maintained.

Conventionally, the vibration component of the motor torque is extracted using a speed sensor that detects the motor speed or senses the rotation speed of the driving wheel. However, as described above, due to the resolution limit of the speed sensor, There is a limitation in extracting the vibration component from the detection signal of the speed detecting sensor at the low speed of the driving wheel (particularly, at the low speed when decelerating), and as a result, the vibration due to the motor torque ripple at low speed traveling of the electric vehicle can not be reduced.

In order to solve such a problem, the present invention extracts a ripple which is a vibration component of a motor torque by using a brake acceleration sensor in order to remove a motor torque ripple at a low-speed running of an electric automobile (particularly, (Ripple) included in the motor command torque can be easily removed by outputting the compensation torque to the actual motor command torque through the iterative learning control, thereby improving the vehicle vibration reduction performance at low speeds .

Hereinafter, a vibration control method for an electric vehicle using the brake acceleration sensor according to the present invention will be described in more detail with reference to FIG.

First, the vibration component of the motor torque is extracted from the tire same radius information, including the detection signal of the brake acceleration sensor, that is, the deceleration detection signal of the vehicle.

More specifically, the motor torque is estimated based on the deceleration detection signal and the tire radius information of the brake acceleration sensor, and then the estimated motor torque is passed through the band path to calculate only the vibration component (N / m) of the motor torque Can be extracted.

First, the motor torque [acceleration [m / s ^ 2] * mass_vehicle / tire radius / reduction ratio] is calculated using the product of the conversion factor and the acceleration [m / s ^ 2] measured by the brake acceleration sensor. And then a first-order high pass filter is applied to the obtained motor torque to extract a vibration component.

The extracted vibration components are classified by the rotor position of the motor and stored in the memory.

Next, based on the stored vibration component data, a step of extracting a compensation torque to compensate for an actual motor command torque includes the steps of repeating learning control for extracting compensation torque based on vibration component data extracted as described above and stored in a memory Is carried out.

Hereinafter, an iterative learning control process for extracting the compensation torque will be described.

First, in the state where the vibration component e is stored in the memory by the rotor position? In the first rotation cycle (i = 1) of the motor rotor, the gain is stored in the vibration component stored for each rotor position? And stores the multiplied compensation torque [? T _i (?)] In the memory.

Next, the compensation torque [? T _i (?)] And the vibration component [e _i (?)] Of the rotor position? Of the previous rotation cycle i and the vibration component e _{i + 1} (&thetas;)] is multiplied by the gain, and a new compensation torque is set as a sum of the sum and the sum.

Is a gain for determining a new compensation torque and? Is a compensation torque [? T _i (?) Calculated at the current rotor position (?) Of the previous rotation period (i) θ)], Γ is a variable for determining how much to reflect the vibration component [e _i (θ)] generated at the current rotor position (θ) of the previous rotation period (i), and Φ _{Ei + 1} (?)] Of the next rotation period (i + 1).

Finally, as described above, the motor torque vibration component extracted based on the detection signal of the brake acceleration sensor is output as a new compensation torque through the iterative learning control to compensate for the motor command torque, (Ripple) can be easily removed to improve vehicle vibration reduction performance at low speeds.

Claims (4)

Extracting a vibration component of the motor torque from the deceleration detection signal of the vehicle and the tire radius information;
Storing the extracted vibration component in a memory for each rotor position of the motor;
Performing repetitive learning control for compensating torque extraction based on stored vibration component data;
Compensating the compensation torque obtained through the iterative learning control to the motor command torque;
And a vibration acceleration sensor for detecting vibration of the electric vehicle.
The method according to claim 1,
The step of extracting the vibration component of the motor torque comprises:
Estimating a motor torque based on a deceleration detection signal of the brake acceleration sensor and tire radius information;
Passing the estimated motor torque through a bandpass to extract a vibration component;
And a vibration sensor for detecting vibration of the electric vehicle.
The method according to claim 1,
Wherein the iterative learning control comprises:
Storing a vibration component (e) for each rotor position (?) At an initial rotation period (i = 1) of the motor rotor;
Once storing the compensation torque [ΔT _i (θ)] multiplied by the gain (Gain) is stored in each vibration component E position (θ) and;
Previous rotation period (i) the rotor position (θ) by compensating the torque of [ΔT _i (θ)] and the vibration component [e _i (θ)], the vibration component of the next rotation cycle _{(i + 1) [e i} + 1 (&thetas;)&thetas;) by a gain;
And a vibration acceleration sensor for detecting vibration of the electric vehicle.
The method of claim 3,
The gain is:
(?) For determining how much to reflect the compensating torque? T _i (?) Calculated at the current rotor position? Of the previous rotation period (i) and the current rotor position (? whether θ) how reflect the vibration component [e _i (θ)] are vibration components _{[e i + 1 (θ)} ] of the variable (Γ) to determine how much reflected, and then the rotation period (i + 1) the called out by the And a parameter (?) For determining the vibration of the electric vehicle.

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