KR102141901B1 - Fuel pump motor control apparatus and method - Google Patents

Abstract

The present invention relates to a fuel pump motor control device and a control method thereof. The fuel pump motor control device of the present invention comprises: a control unit for comparing a target output corresponding to an input signal received from a main control unit of a vehicle with a current output of a motor provided in a fuel pump, and generating a control signal to drive the motor in accordance with a comparison result; a motor driving unit for driving the motor in accordance with the control signal of the control unit; and an estimating unit for estimating a position and rotation speed of a rotor provided in the motor based on a driving current applied to the motor sensed by a shunt resistor connected to the motor driving unit. The control unit calculates a required current measurement time for each current value of the driving current applied to the motor, and controls a current measurement time to be changed in accordance with the calculated current value such that torque ripple caused by an excessive current measurement time can be minimized by applying a minimum current measurement time capable of normal current measurement in accordance with current applied to the motor.

Description

FUEL PUMP MOTOR CONTROL APPARATUS AND METHOD}

The present invention relates to a fuel pump motor control device and a control method, and more particularly, to a fuel pump motor control device and control method for controlling driving of a fuel pump motor that supplies fuel to an engine.

In general, liquefied petroleum gas (Liquefied Petroleum Gas, hereinafter referred to as'LPG') has a property of being easily liquefied by cooling or pressurization and, conversely, by vaporizing by heating or decompression, it is usually pressurized (liquefied) under high pressure Stored in a container, it is easier to handle and has a higher calorific value than other gases.

Conventionally, the gas liquefied in the vehicle using LPG is introduced into the engine in a gaseous state together with air, so that it can be ignited in the combustion chamber of the engine. There was a problem that it was lowered.

In order to solve this problem, recently, a liquid liquefied petroleum injection (Liquifid Petroleum Injection) engine configured to inject the liquefied gas supplied from the fuel tank to the injector in the same way as the gasoline engine in the same way as the gasoline engine. Use to improve maneuverability and improve output.

For example, the applicant has filed a patent application by registering the LPIA system and the fuel pump motor driving technology applied thereto in a number of patent documents 1 to 2 as described below.

On the other hand, the motor that drives the fuel pump uses a brushless DC motor (hereinafter referred to as'BLDC motor') to secure high efficiency, long life, and reliability, and in particular, a sensorless BLDC motor. It is common to use.

In addition, since the LPI system according to the prior art directly injects liquid fuel from the injector, a positive displacement pump is applied to the fuel pump, and a motor driver that controls the BLDC motor applied to the fuel pump is mounted inside the fuel tank.

The motor driver receives the PWM signal from the ECU of the vehicle and checks the current RPM of the motor in comparison to the motor speed, and the motor RPM is 5 steps according to the internally set program, for example, 1st stage: 500RPM, 2nd stage: 1000RPM, 3rd stage : 1500RPM, 4th stage: 2000RPM, 5th stage: 2800RPM to control fuel flow.

Republic of Korea Patent Registration No. 10-1094882 (announced on December 15, 2011) Republic of Korea Patent Registration No. 10-1021108 (announced on March 14, 2011)

On the other hand, the LPI system according to the prior art applies a positive displacement pump to the fuel pump, and controls the driving of the motor applied to the fuel pump using a BLDC control method, thereby continuously generating noise when driving the fuel pump.

The main causes of noise generated when driving the fuel pump are collision of the flange of the pump and the shaft of the motor and torque ripple when controlling the BLDC motor.

As described above, in order to improve the noise generated by the fuel pump, a method of attaching a sound absorbing material or a sound insulating material to the pump part was used, but this increased the manufacturing cost of the product and lowered workability.

And the LPI system according to the prior art measures the back electromotive force of the motor by the BLDC control method from the motor driver, predicts the rotor position based on the measured back electromotive force, and controls the motor by controlling the 3-phase current according to the predicted rotor position. Drive.

However, the improvement of the motor control method as described above is limited in reducing noise generated from the positive displacement pump.

That is, the turbine pump has less noise than the positive displacement pump, and when driven by a BLAC control method, it is possible to obtain a noise reduction effect compared to when driven by a BLDC control method.

On the other hand, when the turbine pump is driven by the BLAC control method, the noise is reduced compared to the case of the BLDC control method, but the maximum power may be lowered.

For example, FIG. 1 is a configuration diagram of a motor driving unit applied to a fuel pump motor control device according to the prior art, and FIG. 2 is a graph illustrating a required current measurement time according to a motor applied current. And Figure 3 is a diagram illustrating a required current measurement time according to the current applied to the motor, Figure 4 is a diagram illustrating a current measurement point, Figure 5 is a torque ripple caused by excessive current measurement time during normal BLAC control Output torque graph included.

The motor driving unit 1 applied to the fuel pump motor control device includes first and second switching units 2 and 3 that constitute a three-phase full bridge circuit using three FETs or MOSFET elements, respectively, as shown in FIG. 1. ).

In addition, one shunt resistor 4 for measuring the phase current is connected between the second switching unit 3 and the ground potential line GND, and the inverter includes first and second switching units 2 and 3 A voltage amplifying stage 6 is provided between the controller 5 driving the circuit, that is, between the motor driver and the shunt resistor 4.

As described above, a single shunt resistor 4 is applied to the motor driving unit 1 to measure the three-phase current of the motor 8 provided in the fuel pump 7.

In this one-shunt BLAC control, current measurement is performed twice during a space vector pulse width modulation (hereinafter referred to as'SVPWM') period.

Here, the current measurement time (T _min ) for measuring the current includes current measurement and analog digital conversion (ADC) time.

2 and 3, the current measurement time should be sufficiently larger than the ringing time, and the ringing time is prolonged in proportion to the magnitude of the current applied to the motor.

In FIG. 2, the actual current value is shown as a yellow line, and the remaining lines are values output from the digital analog converter by measuring the current value measured by the shunt resistor.

It can be seen through FIG. 2(a) that the current measurement time is insufficient and the current is not accurately measured.

On the other hand, when the current measurement time is sufficiently set as shown in FIG. 2B, it can be confirmed that the actual current value is normally measured.

In the current measurement technique according to the prior art, as shown in FIG. 4, in order to secure the current measurement time, torque ripple occurs as SVPWM is performed.

That is, in the current measurement technique according to the prior art, the current measurement time is secured by moving the output of the SVPWM in the state where the current measurement time is not secured to the V phase and the W phase.

Through this, the current measurement time can be secured, but as the linearity is lost, it has been a cause of torque ripple.

In particular, as shown in FIG. 5, the more the current measurement time is increased, the more severe the torque ripple is.

However, the current measurement technique according to the prior art calculates the required current measurement time at the maximum current applied to the system, and uses the calculated current measurement time fixed.

For this reason, the current measurement technique according to the prior art has a problem in that excessive torque ripple occurs as the current measurement time is longer than necessary even when the current applied to the motor is low.

An object of the present invention is to solve the problems as described above, it is to provide a fuel pump motor control device for driving the fuel pump to supply the fuel in the liquid state to the engine in a high pressure state.

Another object of the present invention is to provide a fuel pump motor control apparatus and control method capable of minimizing the occurrence of torque ripple in the process of controlling the driving of the motor by measuring the current using a shunt resistor.

Another object of the present invention is to provide a fuel pump motor control device and a control method that can ensure the stability of current measurement by minimizing the current measurement time according to the current applied to the motor in the process of switching the control method.

In order to achieve the above object, the fuel pump motor control apparatus according to the present invention compares the target output corresponding to the input signal received from the main control unit of the vehicle with the current output of the motor provided in the fuel pump and compares the result. The control unit generates a control signal to drive the motor accordingly, the motor driving unit for driving the motor according to the control signal of the control unit, and the rotor provided in the motor based on the driving current applied to the motor sensed by the shunt resistor connected to the motor driving unit It includes an estimation unit for estimating the position and rotational speed, and the control unit calculates a required current measurement time for each current value of the driving current applied to the motor, and controls to change the current measurement time according to the calculated current value. Is done.

In addition, in order to achieve the above object, the fuel pump motor control method according to the present invention (a) receives an input signal corresponding to a target output to drive the motor provided in the fuel pump from the main control unit of the vehicle Step, (b) estimating the rotational speed and position of the rotor provided in the motor using the estimator, and (c) driving the motor based on the BLAC control method based on the target output from the controller and the current output of the motor. And generating a control signal for controlling the current, and the controller calculates a required current measurement time for each current value of the driving current applied to the motor, and controls to change the current measurement time according to the calculated current value. It is characterized by.

As described above, according to the fuel pump motor control apparatus and control method according to the present invention, it is possible to control the driving current applied to the motor and to control the time for measuring the current according to the sensed current value. Is obtained.

In addition, according to the present invention, the effect that the minimum current measurement time for normal current measurement can be applied according to the current applied to the motor is obtained.

Therefore, according to the present invention, the effect that the torque ripple generated due to the excessive current measurement time can be minimized is obtained.

Therefore, according to the present invention, it is possible to minimize the current measurement time in the low RPM region of the motor, thereby obtaining the effect of preventing torque ripple.

As a result, according to the present invention, by suppressing the occurrence of torque ripple due to excessive current measurement time, an effect that the stability of the current measurement can be ensured is obtained.

1 is a configuration diagram of a motor driving unit applied to a fuel pump motor control device according to the prior art,
2 is a graph illustrating the required current measurement time according to the motor applied current,
3 is a diagram illustrating the required current measurement time according to the current applied to the motor,
4 is a view illustrating a current measurement point,
5 is an output torque graph including torque ripple caused by excessive current measurement time during general BLAC control;
6 is a configuration diagram of an LPI system to which a fuel pump motor control device according to a preferred embodiment of the present invention is applied,
7 is a detailed configuration diagram of a fuel pump motor control device shown in FIG. 6;
8 is a flow chart illustrating step by step a control method of a fuel pump motor control device according to a preferred embodiment of the present invention.

Hereinafter, a fuel pump motor control apparatus and a control method according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In this embodiment, a description will be given using a fuel pump motor (hereinafter abbreviated as'motor') that is applied to the LPI system.

The LPIA system is a gas fuel system developed to improve the fuel efficiency of a gas fueled vehicle, and is configured to supply liquid gas fuel to the engine and recover the remaining gas fuel injected from the engine into a cylinder.

However, the present invention is not necessarily limited to this, as well as a gas fuel supply system that supplies gaseous fuel in a liquid state, such as an Elpia system or an Elpdiay system, to various fuel supply systems such as a gasoline or diesel direct injection system. It should be noted that it may be changed to apply.

The ringing time included in the current measurement time varies in length in proportion to the amount of current applied to the motor.

Therefore, the current measurement time also changes in proportion to the magnitude of the current applied to the motor.

Accordingly, the fuel pump motor control apparatus and control method according to the present invention calculates the required current measurement time for each value of the current applied to the motor, and applies it by changing the current measurement time according to the current value.

As described above, according to the present invention, by applying a minimum current measurement time capable of normal current measurement according to a current applied to a motor, torque ripple caused by excessive current measurement time can be minimized, and stability of current measurement is guaranteed. Can be.

Next, a configuration of a fuel pump motor control device according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7.

FIG. 6 is a configuration diagram of an LPI system to which a fuel pump motor control apparatus according to a preferred embodiment of the present invention is applied, and FIG. 7 is a detailed configuration diagram of the fuel pump motor control apparatus shown in FIG. 6.

First, the LPI system 10 to which the fuel pump motor control device according to the preferred embodiment of the present invention is applied is a fuel pump 12 for pumping fuel stored in a bomb, as shown in FIG. 6, in a driving state of the vehicle. A motor provided in the fuel pump 12 and the target output received from the main control unit 11 through communication with the main control unit 11 and the main control unit 11 for calculating the target output of the fuel supplied to the engine based on the High pressure for comparing the current output of 13) and controlling the driving of the motor 13 according to the comparison result, the fuel pump motor control device 20 and the fuel pumped by the fuel pump 12 to a predetermined high pressure It may include a pump 14, an injector 15 for injecting fuel pressurized at high pressure into the cylinder of the engine, and an acceleration state detection unit 16 for sensing an acceleration state of the vehicle.

The main control unit 11 controls the target output of the motor 13, that is, a stage input signal corresponding to the target RPM, to adjust the flow rate of fuel supplied to the engine based on the driving state of the vehicle. It can be delivered to the control unit 21.

The acceleration state detection unit 16 may be provided as an acceleration pedal sensor that senses the angle of the accelerator pedal when the driver operates the accelerator pedal. The accelerator pedal sensor transmits an acceleration state detection signal that senses the angle of the accelerator pedal to the main controller 11.

The fuel pump 12 is provided as a turbine pump having a noise reduction effect on torque ripple compared to a positive displacement pump, and the motor 13 may be provided as a sensorless BLDC motor.

The fuel pump motor control apparatus 20 according to the preferred embodiment of the present invention includes a target output and a fuel pump 12 corresponding to an input signal received from the main control unit 11 of the vehicle, as shown in FIGS. 6 and 7. ) Compares the current output of the motor 13 provided and controls the control unit 21 generating a control signal to drive the motor 13 according to the comparison result, and drives the motor 13 according to the control signal of the control unit 21 It may include a motor driving unit 23 and an estimation unit 22 for estimating the position and rotational speed of the rotor provided in the motor 13 based on the current sensed by the shunt resistor 43 connected to the motor driving unit 23 have.

The estimation unit 22 may estimate the position and rotational speed of the rotor using the current value sensed by the current sensing unit 44 that senses the current value flowing through the shunt resistor 43.

Therefore, the control unit 21 may determine the current output of the motor 13, that is, the current RPM, using the result estimated by the estimation unit 22, and generate a control signal to control the driving of the motor 13.

The motor driving unit 23 is made of a three-phase full bridge using a field effect transistor (hereinafter referred to as'FET') device, and supplies power applied to the motor 13 Switch.

6 and 7, the motor driving unit 23 includes an inverter circuit 41 including first and second switching units constituting a three-phase full bridge circuit using three FET (or MOSFET) elements, respectively. ) And a motor controller 42 provided as a motor driver for driving the inverter circuit 41.

Here, one shunt resistor 43 for measuring the phase current may be connected between the second switching unit and the ground potential line GND.

The current sensing unit 44 is connected to the input terminal and the output terminal of the shunt resistor 43 to sense the current flowing through the shunt resistor 43 and transmits the detection signal to the mapping unit 31 and estimator 22 of the control unit 21. To deliver.

The three-phase current of the motor can be measured by applying one shunt resistor 43 to the motor driving unit 23 configured as described above.

The control unit 21 receives and receives a stage input signal from the main control unit 11 to drive the motor 13 at a motor output corresponding to any one of a plurality of preset stages, for example, 5 stages, that is, RPM. However, a control signal may be generated to drive the motor 13 in a BLAC control method according to the input signal.

The control unit 21 calculates a required current measurement time for each value of the current applied to the motor 13 and controls the current measurement time to change according to the current value.

To this end, the control unit 21 of the speed controller 32, the speed controller 32 to drive the motor 13 to correspond to the target output according to the input signal of the main control unit 11, as shown in FIG. The output signal of the current controller 33 and the current controller 33 that regulates the current applied to the motor driving unit 23 by receiving the output signal and the rotation speed and the position of the rotor estimated by the estimation unit 22 as an SVPWM signal The current measurement time for each current value of the drive current applied to the signal generator 34 and the motor 13 that generates the converted signal is mapped and stored, and the current measurement time corresponding to the current value sensed by the current detection unit 44 is determined. And a mapping unit 31 that searches and transmits the signal to the signal generator 34.

The mapping unit 31 calculates the required current measurement time by correlating each element determining the current measurement time for each current value detected by the current detection unit 44 that senses the driving current applied to the motor 13 through experimentation Then, the maximum and minimum values of the calculated required current measurement time are set to limit the current measurement time, and finally, the current measurement time is mapped and stored.

In addition, when the current value sensed by the current detection unit 44 is received, the mapping unit 31 searches for a current measurement time corresponding to the received current value and transmits it to the signal generator 34.

Then, the signal generator 34 secures the current measurement time received from the mapping unit 31 when the next SVPWM signal is generated.

As described above, the present invention can be controlled to detect the driving current applied to the motor and to adjust the time for measuring the current according to the sensed current value.

And the present invention can be applied to the minimum current measurement time that can be normal current measurement according to the current applied to the motor.

Due to this, the present invention can minimize torque ripple caused by excessive current measurement time.

Therefore, the present invention can prevent the occurrence of torque ripple by minimizing the current measurement time in the low RPM region of the motor.

As a result, the present invention can ensure the stability of the current measurement by suppressing the occurrence of torque ripple due to excessive current measurement time.

Next, a control method of a fuel pump motor control apparatus according to a preferred embodiment of the present invention will be described in detail with reference to FIG. 8.

8 is a flowchart illustrating step-by-step a control method of a fuel pump motor control device according to a preferred embodiment of the present invention.

When the ignition key (not shown) of the vehicle is turned on or started in step S10 of FIG. 8 to supply power, the fuel pump motor controller 20 pumps the fuel stored in the cylinder to supply it to the engine, a fuel pump The motor 13 provided in (12) is driven (S12).

That is, the control unit 21 of the fuel pump motor control device 20 displays the target output corresponding to the input signal received from the main control unit 11 of the vehicle and the current output of the motor 13 provided in the fuel pump 12. By comparing and generating a control signal to drive the motor 13 according to the comparison result, the driving of the motor 13 is controlled.

When the motor is driven, the current sensing unit 44 senses the driving current flowing through the shunt resistor 43, and the control unit 21 uses the current value sensed by the current sensing unit 44 in the estimation unit 22. Based on the estimated rotor position and rotational speed, feedback control is performed to adjust the current value applied to the motor according to the target output.

At this time, the mapping unit 31 corresponds to each element determining the current measurement time for each current value sensed by the current detection unit 44 that senses the driving current applied to the motor 13 through experiments, and the required current measurement time Is calculated, and the maximum and minimum values of the calculated required current measurement time are set to limit the current measurement time and finally the current measurement time is mapped and stored.

So, when the current value sensed by the current sensing unit 44 is received, the mapping unit 31 searches for the current measurement time corresponding to the received current value and transmits it to the signal generator 34.

Then, the signal generator 34 secures the current measurement time received from the mapping unit 31 when the next SVPWM occurs.

As described above, the control unit 21 may detect the driving current applied to the motor and adjust it to minimize the time for measuring the current according to the sensed current value, thereby reducing torque ripple caused by excessive current measurement time. .

Thereafter, the control unit 21 may control the driving of the motor 13 by receiving the target output set by the main control unit 11 according to the detection signal of the acceleration state detection unit 16.

On the other hand, in step S18, the control unit 21 checks whether the ignition key is turned off and the power supply is stopped, and controls to perform steps S14 to S18 repeatedly until the power supply is stopped.

If the power supply is stopped as a result of the inspection in step S18, the control unit 21 stops driving of each device provided in the fuel pump motor control device 20 and ends.

Through the process as described above, the present invention can be controlled to detect the drive current applied to the motor, and adjust the time for measuring the current according to the sensed current value.

And the present invention can be applied to the minimum current measurement time that can be normal current measurement according to the current applied to the motor.

Due to this, the present invention can minimize torque ripple caused by excessive current measurement time.

Therefore, the present invention can prevent the occurrence of torque ripple by minimizing the current measurement time in the low RPM region of the motor.

As a result, the present invention can ensure the stability of the current measurement by suppressing the occurrence of torque ripple due to excessive current measurement time.

Although the invention made by the present inventors has been described in detail according to the above-described embodiments, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist thereof.

The present invention minimizes the time to measure the current using one shunt resistor based on the current applied to the fuel pump motor to alleviate torque ripple and to control the fuel pump motor control device and control method technology to ensure the stability of the current measurement Applies to.

10: Elpia system
11: Main control unit 12: Fuel pump
13: motor 14: high pressure pump
15: injector 16: acceleration state detection unit
20: fuel pump motor drive
21: control unit 22: estimation unit
23: motor drive
31: mapping unit 32: speed controller
33: current controller 34: signal generator
41: inverter circuit 42: motor controller
43: shunt resistor 44: current sensing unit

Claims (6)

A control unit that compares a target output corresponding to the input signal received from the main control unit of the vehicle with the current output of the motor provided in the fuel pump and generates a control signal to drive the motor according to the comparison result,
A motor driving unit for driving the motor according to the control signal of the control unit and
It includes an estimation unit for estimating the position and rotational speed of the rotor provided in the motor based on the driving current applied to the motor sensed by the shunt resistor connected to the motor driving unit,
The control unit is a speed controller for driving the motor to correspond to the target output according to the input signal of the main control unit,
A current controller that receives feedback of the output signal of the speed controller and the rotational speed and position of the rotor estimated by the estimator to adjust the current applied to the motor driver,
A signal generator for generating a signal converted from the output signal of the current controller into a space vector pulse width modulated signal, and
Mapping that stores and maps the current measurement time for each current value of the driving current applied to the motor and retrieves the current measurement time corresponding to the detected current value from the current sensing unit that senses the current flowing through the shunt resistor and delivers it to the signal generator Including wealth
A fuel pump motor control device comprising calculating a required current measurement time for each current value of a driving current applied to a motor and controlling to change the current measurement time according to the calculated current value. delete According to claim 1,
The mapping unit calculates the required current measurement time by correlating each element determining the current measurement time for each current value that senses the driving current applied to the motor, and sets the maximum and minimum values of the calculated required current measurement time to set the current Limits the measurement time and maps and stores the current measurement time. When the current value of the driving current sensed by the current sensing unit is received, the current measurement time corresponding to the received current value is retrieved and transmitted to the signal generator.
The signal generator secures the current measurement time received from the mapping unit when the next spatial vector pulse width modulated signal is generated, thereby reducing torque ripple caused by the current measurement time excess. In the control method of the fuel pump motor control device according to claim 1 or 3,
(A) receiving an input signal corresponding to a target output to drive the motor provided in the fuel pump from the main control unit of the vehicle,
(b) estimating the rotational speed and position of the rotor provided in the motor using an estimation unit, and
(c) a control unit generating a control signal for controlling the driving of the motor based on the BLAC control method based on the target output and the current output of the motor,
The step (c) is (c1) driving the motor to correspond to the target output according to the input signal from the main controller in the speed controller of the controller,
(c2) receiving an output signal of the speed controller from the current controller and the rotational speed and position of the rotor estimated by the estimating unit to adjust the current applied to the motor driving unit;
(c3) generating a signal in which a signal generator converts the output signal of the current controller into a spatial vector pulse width modulated signal, and
(c4) mapping and storing the current measurement time for each current value of the driving current applied to the motor in the mapping unit, and retrieving the current measurement time corresponding to the current value sensed by the current detection unit and transferring the measured time to the signal generator. So
A method for controlling a fuel pump motor, wherein the required current measurement time is calculated for each current value of the driving current applied to the motor and controlled to change the current measurement time according to the calculated current value. delete According to claim 4,
The mapping unit calculates the required current measurement time by correlating each element determining the current measurement time for each current value that senses the driving current applied to the motor, and sets the maximum and minimum values of the calculated required current measurement time to set the current Limits the measurement time and maps and stores the current measurement time. When the current value of the driving current sensed by the current sensing unit is received, the current measurement time corresponding to the received current value is retrieved and transmitted to the signal generator.
The signal generator is to control the fuel pump motor, characterized in that to secure the current measurement time received from the mapping unit when the next space vector pulse width modulation signal is generated, thereby reducing torque ripple caused by the current measurement time excess.

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