KR20190056490A - Fuel pump device for vehicles and method for controlling voltage thereof - Google Patents

Abstract

The present invention relates to a fuel pump device for a vehicle and a method for controlling the voltage thereof. A fuel pump device for a vehicle according to the present invention is a fuel pump device for a vehicle supplying a fuel amount required by an engine by using a motor pump, comprising: a motor generating torque with a size proportional to the amount of an applied current; and a control unit controlling voltage such that a current can be applied to the motor. The control unit controls voltage such that, when a torque ripple appears, a harmonic current generating torque in a direction opposite to the generated torque can be applied as well so as to offset a torque ripple component.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a fuel pump apparatus for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump apparatus for a vehicle and a voltage control method thereof, and more particularly to a fuel pump apparatus for a vehicle using a motor pump and a voltage control method for determining a fuel supply amount thereof.

Recently, the awareness of environmental preservation such as carbon dioxide abatement has widened, and efforts to apply environmentally friendly parts have been increasing in the automobile industry.

Fuel pumps that supply fuel to the engine may use BLDC motor pumps instead of DC motor pumps, though they are expensive for environmental cost impact and efficiency. BLDC motor (brushless dc motor) is a type that enhances durability by replacing wearable brush inside the motor with electronic device. It is environment-friendly product because it does not need maintenance such as brush replacement as compared with general DC motor can do.

Generally, a BLDC motor uses a PCU (Pump Control Unit) for controlling a voltage, and its driving principle is as follows. First, the voltage applied to the motor can be controlled by controlling the voltage through the PCU. Second, the amount of the controlled current can determine the value of the torque generated in the motor (proportional to the applied current value) to control the amount of fuel supplied to the engine. That is, the BLDC motor controls the amount of fuel to be supplied to the engine through the PCU.

Fig. 1A shows a top view of a vehicle under-body through which a fuel tank drawn from a fuel tank and a fuel tank passes, and Fig. 1B shows a bottom view.

As shown in FIG. 1A, a fuel pump 20 having a BLDC motor is located above the fuel tank 10. The fuel tube 30 is drawn out from the fuel tank 10 and the fuel tube 30 drawn out from the fuel tank 10 as shown in Fig. .

At this time, the BLDC motor in the fuel pump 20 may have an unstable torque value (for example, torque ripple), and this irregular torque value may cause vibration of the shaft inside the fuel pump 20 ≪ / RTI >

That is, when the fuel pump is driven to supply the fuel, the torque ripple component of the BLDC motor inside the fuel pump vibrates the shaft to generate mechanical vibration and noise. In severe cases, So that vibration and noise can be directly transmitted to the passenger while the fuel tube 30 is brought into contact with the vehicle body.

The inventors of the present invention have studied for a long time to solve vibration and noise problems, and after trial and error, have come to complete the present invention.

Embodiments of the present invention provide a vehicle fuel pump apparatus and a voltage control method thereof that can reduce a torque ripple involved in driving a BLDC motor to provide a quieter operating environment.

On the other hand, other unspecified purposes of the present invention will be further considered within the scope of the following detailed description and easily deduced from the effects thereof.

A fuel pump apparatus for a vehicle that supplies a fuel amount required for an engine using a motor pump according to an embodiment of the present invention includes a motor that generates a torque having a magnitude proportional to an amount of current applied thereto; And a control unit for controlling a voltage applied to the motor so that a current is applied to the motor, wherein the control unit controls the motor so that harmonic currents that generate torque in a direction opposite to the generated torque to cancel the torque ripple component So that the voltage can be controlled as much as possible.

The controller obtains a torque waveform generated by the motor to calculate an average torque, and can calculate the harmonic current using the difference between the torque waveform and the average torque.

A method of controlling a voltage of a vehicle fuel pump apparatus that supplies a fuel amount required for an engine using a motor pump according to an embodiment of the present invention includes the steps of controlling a voltage to be applied to the motor based on the amount of fuel to be supplied The motor generates a torque proportional to the amount of current applied; Deriving a harmonic current that generates torque in a direction opposite to the generated torque; And controlling the voltage so that the derived harmonic current is applied together with the motor.

The deriving may include obtaining a torque waveform generated by the motor to calculate an average torque, and deriving a harmonic current using the difference between the torque waveform and the average torque.

This technology can reduce the torque ripple involved in driving the BLDC motor, which can provide a quieter operating environment.

FIG. 1A shows a top view of a vehicle under-body through which a fuel tank drawn from a fuel tank and a fuel tank pass. FIG.
Figure 1B shows a bottom view of Figure 1A.
2 is a diagram showing a detailed configuration of a fuel pump apparatus for a vehicle according to an embodiment of the present invention.
3 is a view schematically showing a principle of controlling a torque ripple component by a fuel pump apparatus for a vehicle according to an embodiment of the present invention.
4 is a flowchart showing a voltage control method of a control unit of a fuel pump apparatus for a vehicle according to an embodiment of the present invention, according to the flow of time.
5A and 5B schematically illustrate a voltage control method of a fuel pump apparatus for a vehicle according to an embodiment of the present invention in comparison with a conventional voltage control method. And a voltage control method, respectively.
It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Hereinafter, the most preferred embodiment of the present invention will be described. In the drawings, the thickness and the spacing are expressed for convenience of explanation, and can be exaggerated relative to the actual physical thickness. In describing the present invention, known configurations irrespective of the gist of the present invention may be omitted. It should be noted that, in the case of adding the reference numerals to the constituent elements of the drawings, the same constituent elements have the same number as much as possible even if they are displayed on different drawings.

2 is a diagram showing a detailed configuration of a fuel pump apparatus 100 for a vehicle according to an embodiment of the present invention.

2, a fuel pump apparatus 100 for a vehicle according to an embodiment of the present invention (hereinafter referred to as a fuel pump apparatus) includes a motor 110 and a control unit 120 .

The fuel pump apparatus 100 uses a motor pump to supply an amount of fuel necessary for the engine.

The motor pump is a pump using the output of the motor 110.

The motor 110 generates a torque proportional to the amount of the applied current, and the controller 120 controls the voltage applied to the motor 110 to apply the current.

The motor 110 may be a BLDC motor, and the control unit 120 may be a PCU. The present invention is not limited thereto and various types of motors for generating torque proportional to the amount of applied current and various modules for controlling the voltage to be applied to the motor may be applied.

Ultimately, the fuel pump apparatus 100 controls the torque value of the pump internal motor to control the amount of fuel supplied to the engine.

The fuel pump apparatus 100 according to the embodiment of the present invention controls the torque value required for fuel supply through the voltage control as described above, and further controls the torque ripple component.

The torque ripple is an amplitude of a torque generated when the motor is rotated by an external driving force in a load state. The fuel pump apparatus according to the embodiment of the present invention controls the torque ripple component together to reduce an excitation force transmitted to the shaft inside the pump .

3 is a view schematically showing the principle of controlling the torque ripple component by the fuel pump apparatus 100 for a vehicle according to the embodiment of the present invention.

Referring to Fig. 3, first, a torque waveform generated by a motor is shown. Then, an average torque value Tavg appears. The average torque value corresponds to the torque that substantially contributes to the output of the motor.

On the other hand, when the ideal current and voltage are applied, only the average torque value is obtained. In practice, however, harmonic components are generated in the applied voltage and current, and therefore, a torque rip component do.

To offset this torque ripple component, the voltage can be controlled such that a torque can be generated in the opposite direction of the generated torque.

Specifically, the control unit 120 according to the embodiment of the present invention calculates a required amount of torque (that is, a quantity of fuel to be supplied) and calculates a harmonic current (i _H ) capable of reducing the torque ripple component The voltage is controlled to be applied.

The applied harmonic current reduces the torque ripple component and reduces the excitation force that can be transferred to the shaft inside the pump. Therefore, a more quiet driving environment according to the embodiment of the present invention can be achieved.

Hereinafter, a process of deriving a harmonic current capable of reducing the torque ripple component by the controller 120 will be described in more detail.

4 is a flowchart showing a voltage control method of a control unit of a fuel pump apparatus for a vehicle according to an embodiment of the present invention, according to the flow of time.

4, the voltage control method of the vehicular fuel pump apparatus control unit 120 includes a step S210 of controlling the voltage based on the amount of fuel to be supplied, a step of deriving a ripple harmonic current canceling the torque ripple (S220), and controlling the voltage so that the derived harmonic current is applied to the motor (S230).

First, in step S210, the voltage is controlled so that current is applied to the motor based on the amount of fuel to be supplied.

The following equations correspond to commonly used output equations to consider the output in motor design.

Where v is the voltage applied to the motor, i is the current applied to the motor, T is the torque generated by the motor, and w is the angular speed of the motor.

Therefore, the control unit can control the voltage to be applied to the motor based on the amount of fuel to be supplied (that is, the required torque amount). The motor generates torque proportional to the amount of applied current.

In step S220, a harmonic current is generated that generates torque in a direction opposite to the torque generated by the motor.

As described above, not only the fundamental wave but also the harmonic components are generated in the voltage and current applied to the motor, so that a torque ripple component is generated. Therefore, in order to reduce the torque ripple component, it is necessary to generate the torque in the opposite direction of the generated torque ripple waveform.

To this end, in step S220, the torque value generated by the motor is obtained to calculate the average torque, and the harmonic current can be derived using the difference between the torque value and the average torque. It will be discussed in more detail below.

First, the waveforms of the variables (voltage, current, torque) contributing to the output of the motor change with time as shown in the following equation.

Time-dependent values can then be treated as DC values through d-q axis transformation. To convert the values of the three phases (U, V, W phase) of the motor to the d-q axis, we can use the d-q axis transformation matrix as shown in the following equation.

Using the current, voltage, and torque values converted to the dq axis, the order of the harmonic current (i _H ) to be applied to offset the torque ripple component and the values to be applied to the order can be derived .

Specifically, the control unit 120 can derive the harmonic current using the following equation. This is because the rotary coordinate system can be converted to a d-q axis and treated as a DC value.

Here, i _H denotes a harmonic current to be applied for torque ripple reduction.

In Equation (4), the meaning of (T-Tavg) means that only the torque ripple component remains when the average torque value (constant value) is subtracted from the torque waveform, And the current is applied to the electrode.

When the harmonic current derived by the control unit 120 is applied to the motor 110 through the above equations, the current applied to the motor 110 is converted to the fundamental wave current and the specific harmonic derived from the above- Corresponds to the sum of the corresponding currents.

For example, the voltage value is represented by a sine and cosine function as a sum of a fundamental wave and a harmonic according to Equation (2), and the current value is also expressed as a sine and cosine function according to Equation (2) The product of the voltage and the current corresponds to the product of the torque and the angular velocity, and since the angular velocity is a constant, the torque value is also a function of the sine and cosine, and is the sum of the fundamental wave and the harmonic Lt; / RTI > Then, in the case of the torque ripple, since the torque ripple is generated mainly by a multiple of 6, if the value of the multiple order of 6 of the torque ripple is known, the current value corresponding to each harmonic wave can be derived by using Equation have.

In this way, the controller 120 derives the order of the harmonic current and the values to be applied to the order using the torque, voltage, and current values generated when the motor 110 is driven, The torque ripple can be reduced (S230).

5 is a diagram schematically showing a voltage control method of a fuel pump apparatus for a vehicle according to an embodiment of the present invention, in comparison with a conventional voltage control method. FIG. 5A shows a conventional voltage control method, and FIG. 5B shows a voltage control method according to the present invention.

First, referring to FIG. 5A, when it is determined that fuel amount control to be supplied to the engine is necessary, the pump voltage is controlled. As the pump voltage is controlled, a corresponding current is applied to the motor, and the torque value of the motor is determined in proportion to the applied current amount. Through this process, fuel quantity control is performed. On the other hand, when the amount of fuel to be supplied to the engine is not required, the control of the pump voltage is unnecessary.

On the other hand, according to the embodiment of the present invention, as shown in FIG. 5B, when the pump voltage is controlled, the harmonic voltage application is performed together. Accordingly, a current corresponding to the value obtained by adding the harmonic voltage is applied to the motor, and the torque value of the motor is determined in proportion to the applied current amount, so that the torque ripple can be reduced.

According to the fuel pump apparatus for a vehicle according to the embodiment of the present invention, the torque ripple involved in driving the BLDC motor can be reduced to provide a more quiet operating environment.

It is to be noted that the technical spirit of the present invention has been specifically described in accordance with the above-described preferred embodiments, but it is to be understood that the above-described embodiments are intended to be illustrative and not restrictive. In addition, it will be understood by those of ordinary skill in the art that various embodiments are possible within the technical scope of the present invention.

10: Fuel tank
20: Fuel pump
30: fuel tube
40: underbody
100: Vehicle fuel pump device
110: motor
120:

Claims (4)

A fuel pump apparatus for a vehicle that supplies a fuel amount required for an engine using a motor pump,
A motor for generating a torque having a magnitude proportional to the amount of applied current; And
And a controller for controlling a voltage to be applied to the motor,
Wherein the control unit controls the voltage such that a harmonic current that generates a torque in a direction opposite to the generated torque to cancel the torque ripple component is applied together when the torque ripple occurs. The method according to claim 1,
Wherein the control unit calculates the average torque by acquiring the torque waveform generated by the motor and calculates the harmonic current using the difference between the torque waveform and the average torque. 1. A voltage control method for a fuel pump apparatus for a vehicle that supplies a fuel amount required for an engine using a motor pump,
Controlling a voltage to be applied to the motor based on an amount of fuel to be supplied, the motor generating a torque proportional to the amount of current applied;
Deriving a harmonic current that generates torque in a direction opposite to the generated torque; And
And controlling the voltage so that the derived harmonic current is applied together with the motor. The method of claim 3,
Wherein the deriving comprises deriving a torque waveform generated by the motor to calculate an average torque and deriving a harmonic current using a difference between the torque waveform and the average torque.

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