KR101978250B1 - Method and apparatus for controlling vfs frequency - Google Patents

Abstract

According to an embodiment of the present invention, an apparatus for controlling a VFS frequency comprises: a power supply part for supplying direct current power; a solenoid receiving a direct current voltage from the power supply part; a first diode connected to the power supply part to allow reflux of energy stored in the solenoid; an observation part for observing the voltage frequency of the solenoid; and a control part performing control to have a current of a duty ratio at which a dither signal is added to pulse width modulation (PWM) corresponding to a target current for driving the solenoid by using the observed solenoid voltage frequency. The control part includes a driving switch, and a second diode connected to the first diode and the solenoid to allow reflux of energy stored in the solenoid in response to the switching of the driving switch.

Description

METHOD AND APPARATUS FOR CONTROLLING VFS FREQUENCY}

The present invention relates to a method and apparatus for controlling the frequency of a variable force solenoid (VFS). More specifically, the present invention relates to a method and apparatus for controlling the amount of current to maintain the VFS control characteristics Dither and Pulse Width Modulation (PWM) frequencies.

The solenoid valve is a valve used to control the flow of a certain fluid or gas. The solenoid valve generates electromagnetic force by the change of an electrical switch, and converts electrical energy into mechanical energy to block or pass the flow or flow of a fluid or gas, or change direction. Perform.

These solenoid valves can be controlled through the current control of the solenoid internally in the vehicle. For precise current control, the solenoid valve needs to control the constant current by receiving the current flowing through the solenoid. The current amount is controlled according to the feedback result value. However, with the development of VFS control technology, the range of inductance and current control of solenoids is increasing, and larger current amplitudes are required to improve hydraulic hysteresis characteristics.

However, the conventional technology does not satisfy this requirement, and there is a problem in that the pulse width modulation (PWM) frequency is not accurately observed within one dither frequency, which is set to match the target current amplitude within the required target current. It switches current within the PWM frequency, but because of the time delay due to external load inductance, it gives up and controls the PWM frequency in the middle to match the target current and amplitude accordingly.

Therefore, in order to solve the problems of the prior art, a device capable of controlling the dual frequency, which is a characteristic of VFS (Variable Force Solenoid) control, is continuously required. The present invention has been proposed to solve this problem.

Republic of Korea Patent Publication No. 10-2009-0010067 (2009.02.09)

The technical problem to be solved by the present invention is to provide a VFS frequency control device that can quickly stabilize the internal voltage of the solenoid.

Another technical problem to be solved by the present invention is to provide a VFS frequency control method that can maintain the customer's PWM frequency characteristics customer while matching the desired solenoid current amplitude.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

VFS frequency control apparatus according to an embodiment of the present invention for achieving the technical problem, a power supply for supplying a DC power, a solenoid receiving a DC voltage from the power supply, connected to the power supply and stored in the solenoid A pulse width modulation (PWM) signal of a current flowing through the solenoid and a dither added to the PWM signal using a first diode for refluxing energy, an observer for monitoring the voltage frequency of the solenoid, and the observed solenoid voltage frequency And a controller configured to control a voltage supplied to the solenoid such that a ratio of a dither signal is constant, wherein the controller is connected to a driving switch, the first diode, and the solenoid, and according to switching of the driving switch. A second to reflux the energy stored in the solenoid It includes a diode.

According to an embodiment of the present disclosure, the controller may control the driving switch to be in an off state so that a current flowing through the solenoid forms a closed loop.

According to an embodiment of the present disclosure, the observation unit is connected to an ungrounded end of the driving switch, and when the current flowing through the solenoid forms a closed loop, the rising edge of the voltage frequency flowing through the solenoid within a preset range. It can be measured.

According to one embodiment, the first diode, the cathode terminal is connected to the power supply and the solenoid, may be a free wheeling diode (FREE WHEELING DIODE).

According to an embodiment of the present disclosure, the second diode may be a zener diode having a breakdown voltage of a predetermined threshold voltage.

According to an embodiment, the second diode may include a plurality of second diodes, and the plurality of second diodes may be connected in parallel.

According to one embodiment, the plurality of second diodes, one end is connected to the anode end of the first diode, the other end is connected to the drive switch terminal, each may have a different breakdown voltage.

According to one embodiment, the driving switch is connected to one end of the solenoid and the cathode end of the second diode, it is possible to determine the on / off of the second diode.

VFS frequency control method according to another embodiment of the present invention for achieving the technical problem, the step of receiving a hydraulic control current value of the solenoid, monitoring the voltage frequency of the solenoid corresponding to the input current value Measuring a number of rising edges of a voltage frequency flowing through the solenoid within a preset range; and adding the measured number of rising edges, a pulse width modulation (PWM) signal of the solenoid, and a dither added to the PWM signal. And controlling the voltage supplied to the solenoid by comparing the ratio of the signals.

According to an embodiment, when the ratio is larger than the measured number of rising edges, the method may further include operating a diode connected in parallel with the solenoid.

According to an embodiment, in the measuring of the voltage frequency, when the current flowing in the solenoid forms a closed loop, the voltage frequency of the solenoid may be measured.

According to an embodiment, the diode may include a plurality of zener diodes connected in parallel, and the plurality of zener diodes may operate with different breakdown voltages, respectively.

According to an embodiment of the present disclosure, the operating of the plurality of diodes may include selectively controlling the plurality of diodes such that a ratio of a PWM signal of a current flowing through the solenoid and a dither signal added to the PWM signal reaches a constant value. Can be.

According to an embodiment of the present disclosure, the preset range includes the number of frequencies of the dither signal, and comparing the ratios and controlling the voltage supplied to the solenoid may include a frequency of the dither signal at the number of rising edges. The ratio divided by the number can be compared.

According to the present invention as described above, it is possible to change the circuit of the VFS frequency control device to reduce the current reduction time flowing through the solenoid to match the PWM frequency characteristics.

In addition, the PWM frequency characteristics are precisely matched, thereby improving the hysteresis characteristics and responsiveness of the hydraulic pressure generated using the solenoid.

In addition, by continuously monitoring the PWM frequency of the solenoid to detect the error of the PWM frequency, it has the effect of stabilizing the solenoid faster.

Effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view showing the configuration of a conventional VFS frequency control device.
FIG. 2 is a diagram illustrating dual frequencies of the solenoid according to FIG. 1.
3 is a view showing the configuration of the VFS frequency control apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating a VFS frequency control method according to an embodiment of the present invention.
5 is a view showing the configuration of the VFS frequency control curve.
6 is a view showing the current flow in the VFS frequency control apparatus according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art.

In addition, terms that are defined in a commonly used dictionary are not ideally or excessively interpreted unless they are specifically defined clearly. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase.

As used herein, “comprises” and / or “comprising” refers to a component, step, operation and / or element that is mentioned in the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

Prior to describing the present invention, a variable force solenoid (VFS) is a load that enables shifting in a vehicle, which can be controlled by a control IC. In addition, the shift stage may be determined by the hydraulic pressure generated using the VFS.

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

1 is a view showing the configuration of a conventional VFS frequency control device, Figure 2 is a view showing the dual frequency of the solenoid according to FIG. 1 and 2, the conventional VFS frequency control apparatus may include a power supply unit 11, a solenoid 21, a first diode 31, and a controller 51.

When the drive switch 51a provided in the control unit 51 is turned on, the direct current voltage supplied from the power supply unit 11 conducts the entire circuit and charges the inductance of the solenoid 21 and turns off. At that moment, the remaining energy is refluxed by the first diode 31. More specifically, the remaining energy may refer to energy of 1 / 2LI ² stored in the inductance of the solenoid 21.

At this time, the control unit 51 adjusts the hydraulic pressure using the amount of current flowing through the solenoid 21 by using a low side switch of the transmission control unit (TCU) and adjusts the hydraulic pressure appropriately in the driving state designated by the driver. It controls the hydraulic system of the transmission so that the gear stage is established. At this time, the low side switch serves to maintain the correct target current to control the hydraulic pressure.

However, in the case of the VFS frequency control device as shown in FIG. 1, when a higher capacity solenoid inductance is installed to improve the performance of the transmission, a time delay in which the current flowing therein decreases during discharge of the VFS frequency control device. Will occur.

That is, in the dual frequency configuration of FIG. 2, the highest point of the current value is repeatedly performed on / off within the PWM frequency range of the solenoid for the time T1 when the driving switch 51a is turned on at one dither frequency D1. To reach.

However, there is a delay as long as the inductance of the solenoid 21 is discharged during the time T2 when the driving switch 51a is turned off, so that the controller 52 does not adjust the PWM frequency within the preset frequency, that is, the time T2. If it doesn't, it will shut itself down.

In addition, the width P of the highest and lowest points of the current value required by the customer and the corresponding PWM frequency value set in one dither frequency D1 cannot be matched using a conventional VFS frequency control device.

As a result, the low side switch cannot maintain the correct target current, resulting in poor transmission performance.

3 is a view showing the configuration of the VFS frequency control device 1 according to an embodiment of the present invention. Referring to FIG. 3, the VFS frequency control device 1 may include a power supply 12, a solenoid 22, a first diode 32, an observer 40, and a controller 52. Additional configurations required in achieving the purpose of may also further include.

Meanwhile, in the following description, the components included in the VFS frequency control device 1 according to an embodiment of the present invention will be described separately, but this is only one embodiment of the configurations, and is different from any one configuration. Of course, this can be implemented in a merged configuration.

The power supply 12 performs a function of supplying DC power required to drive the solenoid 22. The power supply unit 12 may be a battery of a vehicle, and may supply DC power between 9 and 16V using energy stored in the battery.

The solenoid 22 may include a solenoid valve opened and closed according to a DC power applied to an internal coil. When power is applied to the coil of the solenoid valve, the plunger is opened, and when the applied power is cut off, the plunger is closed and the opening and closing of the solenoid valve can be controlled.

The first diode 32 may be connected to the power supply 12 to reflux energy stored in the solenoid 22. The first diode 32 may be a free wheeling diode.

Accordingly, when the voltage charged in the solenoid 22 is discharged, the first diode 32 may prevent the residual voltage from flowing toward the power supply 12.

In addition, the cathode of the first diode 32 may be connected to the power supply 12 and the solenoid 22, and may be connected to the solenoid 22 in parallel.

The observer 40 may monitor the voltage frequency flowing through the solenoid 22. The observer 40 is connected to an ungrounded end of the driving switch 52a, which will be described later, and performs a specific analysis of the voltage frequency flowing through the solenoid 22 according to the flow of current.

The controller 52 uses the voltage frequency of the solenoid 22 observed by the observer 40 to control the PWM signal of the current corresponding to the target current for driving the solenoid 22 and the dither signal added to the PWM signal. The ratio can be controlled to be constant.

To perform this control function, the controller 52 may include a driving switch 52a, a first diode 32, and a second diode 60 connected to the solenoid 22.

More specifically, the driving switch 52a is connected to one end of the solenoid 22 and the cathode end of the second diode 60, and is formed through turn-on and turn-off. The current flowing through the two diodes 60 can be controlled. The driving switch 52a may be implemented using various transistors such as a metal oxide silicon field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), and the like.

In addition, the second diode 60 may be a Zener diode having a breakdown voltage of a predetermined threshold voltage, and a plurality of second diodes 60 may be disposed with different breakdown voltages. Accordingly, the plurality of second diodes 60 may be connected in parallel, and one end thereof may be connected to the anode terminal of the first diode 32 and the other end thereof to the terminal of the driving switch 52a.

The controller 52 compares the ratio of the PWM signal observed by the observer 40 and the dither signal added to the PWM signal, and when it is out of the preset ratio, switches the driving switch 52a to provide a plurality of second diodes ( 60) can be controlled on / off. Accordingly, energy stored in solenoid 22 may be refluxed.

In addition, the controller 52 may control the driving switch 52a to be in an off state so that the current flowing through the solenoid forms a closed loop. Accordingly, the observer 40 may measure the rising edge of the voltage frequency flowing through the solenoid 22 within a preset range.

4 is a flowchart illustrating a VFS frequency control method according to an embodiment of the present invention, Figure 5 is a view showing the configuration of the VFS frequency control curve, Figure 6 is a VFS frequency control device according to an embodiment of the present invention ( A diagram showing the current flow in 1).

4 to 6, the controller 52 receives a hydraulic control current value of the solenoid 22 (S410). The vehicle is provided with a plurality of solenoids, and if the current amount of a specific value is supplied to the plurality of solenoids, the shift stage may be determined. Accordingly, the controller 52 may receive the hydraulic control current values of the plurality of solenoids 22 for determining the shift stage from the outside.

The observer 40 monitors the voltage frequency of the solenoid 22 corresponding to the input current value (S420). As shown in FIG. 5, the voltage frequency may be a dual frequency in which a dither frequency B is added to have a variable amplitude in the PWM frequency A. FIG. In addition, the amplitude C of the dither frequency is the magnitude of the current curve flowing through the solenoid 22. As the amplitude C increases, the hydraulic hysteresis characteristics of the solenoid 22 may be improved.

While the voltage frequency of the solenoid 22 is monitored, when the current flowing to the solenoid 22 forms a closed loop by the drive switch 52a, the observation unit 40 causes the solenoid 22 to be within a preset range. The number of rising edges of the voltage frequency flowing in is measured (S430).

Here, the preset range may mean the frequency number D of the dither signal shown in FIG. 5, and the frequency number D may be set to a large value in order to increase the reliability of the VFS frequency control device 1. .

The controller 52 compares the measured number of rising edges M with the ratio N of the PWM signal of the solenoid 22 and the dither signal added to the PWM signal to determine whether M≥0.9N ( S440). In this case, the number M of rising edges to be compared may be a value obtained by dividing the number of rising edges measured by the frequency number D of the dither signal in a preset range. For example, when the controller 52 frequency number D is 1, the measured rising edge number may be set as a comparison value without additional calculation.

The calculated number of rising edges M may be compared with the frequency period of the dither signal divided by the frequency period of the PWM signal, that is, the ratio N. More specifically, the ratio N of the dither signal is the solenoid 22. It may be the ratio of the PWM signal which should preferably come from one dither signal of the current flowing in.

In addition, the controller 52 may multiply the desired ratio N by a percentile, and compare it with the calculated number M of rising edges, in order to determine a specific control current amount.

As mentioned above, if the calculated rising edge number M is greater than the ratio N of the preferred dither signals multiplied by 0.9, i.e., satisfies a value of 90% or more in the ratio of the preferred dither signals, the solenoid 22 May be determined to be normal and terminate.

On the other hand, when a solenoid having a higher inductance capacity is mounted, a time delay occurs in which the current flowing inside the VFS frequency controller 1 decreases during discharge. At this time, as the delay time increases, the time for the controller 52 to terminate the driving of the solenoid 22 by itself becomes faster, and the number of rising edges M to be measured decreases.

Accordingly, in order to control the desired voltage frequency of the solenoid having various inductance capacities, a process of comparing the number of rising edges M and the ratio N of the preferred dither signals may be divided into a plurality of steps.

Specifically, the control unit 52 is 80% or more, less than 90%, 50% or more, less than 80%, 30% or more, less than 50%, 10% or more of the ratio (R) of the calculated dither signal M is calculated The process determines whether it is less than 30% (S441, S443, S445, S447), and operates the corresponding diode (S451, S453, S455, S457).

Here, the diode may be a zener diode, each having a different breakdown voltage, and may be given an identification number in binary form that the controller 52 can recognize. According to an embodiment, the zener diodes 00, 01, 10 and 10 are operated, respectively.

Accordingly, as the zener diode is operated according to the percentile by comparing the number of rising edges (M) and the ratio (N) of the desired dither signal, the voltage value that the inductance of the solenoid 22 should discharge is increased by the power supply unit 12. The voltage rises to a value larger than the voltage value, and the current decreases quickly, thereby reducing the current delay time.

On the other hand, if the calculated number of rising edges M is less than 10% of the desired ratio N of the dither signals, the controller 52 may terminate the operation of the VFS frequency control device 1, and the solenoid 22 Additional diodes can be installed to match the inductance capacity.

As shown in FIG. 4, a preset plurality of percentile calculation processes may correspond to a current delay attenuation circuit selection process. More specifically, for example, the zener diode 61 of 00 has a breakdown voltage of 17 V, the zener diode 63 of 01 has a breakdown voltage of 20 V, and the zener diode 65 of 10 has a breakdown voltage of 25 V, and 11 times. Zener diode 67 may have a breakdown voltage of 30V.

At this time, when the value obtained by multiplying the desired ratio N by the controller 52 by 30% is smaller than the calculated rising edge number value M, the driving switch 52a may operate the ten zener diodes 65. Can be.

As shown in FIG. 6, when the tenth zener diode 65 operates, a current flowing through the solenoid 22 along the tenth zener diode 65 may form a closed loop. Accordingly, the voltage value at which the inductance of the solenoid 22 is to be discharged rises to a value larger than the voltage value of the power supply 12, and the current decreases quickly to reduce the current delay time.

The above-described percentile percentage calculated by the controller 52 and the breakdown voltage value of the zener diode corresponding thereto are for convenience of explanation of the present invention and may be appropriately set according to a user's setting.

In addition, the process of controlling the on / off of the plurality of diodes 61, 63, 65, and 76 to operate, the ratio of the PWM signal of the current flowing through the solenoid 22 and the dither signal added to the PWM signal is a constant value It may be performed until the energy is reached, that is, until the energy charged in the solenoid 22 is exhausted so that no current delay occurs.

In other words, during a time T2 when the power supply is turned off by the drive switch 52a at the dual frequency of the solenoid 22 monitored by the observer 40, a PWM signal of a predetermined ratio appears at one dither frequency. Until so, the controller 52 may selectively control the plurality of zener diodes to adjust the amount of current.

Thus, by adjusting the dual frequency of the current flowing in the solenoid 22 to the correct target, the hysteresis characteristics and responsiveness of the solenoid 22 hydraulic pressure can be improved. It can also provide the higher current amplitude values required by the customer without dissipation of the PWM signal.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

1: VFS frequency control device
11, 12: power supply
21, 22: solenoid
31, 32: first diode
40: observation unit
51, 52: control unit
51a, 52a: drive switch
60: second diode

Claims (14)

A power supply for supplying DC power;
A solenoid receiving a DC voltage from the power supply unit;
A first diode connected to the power supply to reflux energy stored in the solenoid;
An observation unit for monitoring a voltage frequency flowing through the solenoid; And
A control unit for controlling the voltage supplied to the solenoid such that the ratio of the pulse width modulation (PWM) signal of the current flowing through the solenoid and the dither signal added to the PWM signal is constant using the observed solenoid voltage frequency. ; Including,
The control unit,
Drive switch; And
A second diode connected to the first diode and the solenoid and configured to reflux energy stored in the solenoid according to switching of the driving switch;
VFS frequency control device comprising a. The method of claim 1,
The control unit,
Controlling the drive switch to an off state and controlling the current flowing through the solenoid to form a closed loop to drive the solenoid,
VFS frequency control device. The method of claim 2,
The observation unit,
When the current flowing through the solenoid forms a closed loop, the rising edge of the voltage frequency flowing through the solenoid is measured within a preset range.
VFS frequency control device. The method of claim 1,
The first diode,
A cathode end is connected to the power supply and the solenoid,
FREE WHEELING DIODE IN,
VFS frequency control device. The method of claim 1,
The second diode,
ZENER DIODE, which has a breakdown voltage (BREAKDOWN VOLTAGE) of a preset threshold voltage,
VFS frequency control device. The method of claim 5,
The second diode,
It includes a plurality of second diodes, the plurality of second diodes are connected in parallel,
VFS frequency control device. The method of claim 6,
The plurality of second diodes,
One end is connected to the anode end of the first diode, the other end is connected to the driving switch terminal,
Each having a different breakdown voltage,
VFS frequency control device. The method of claim 1,
The drive switch,
Is connected to one end of the solenoid and the cathode end of the second diode, and determines on / off of the second diode,
VFS frequency control device. Receiving a hydraulic control current value of the solenoid;
Monitoring the voltage frequency of the solenoid corresponding to the input current value;
Measuring the number of rising edges of a voltage frequency flowing through the solenoid within a preset range; And
Controlling the voltage supplied to the solenoid by comparing the measured number of rising edges with a ratio of a pulse width modulation (PWM) signal of the solenoid and a dither signal added to the PWM signal;
VFS frequency control method comprising a. The method of claim 9,
If the ratio is greater than the measured number of rising edges, operating a diode connected in parallel with the solenoid;
VFS frequency control method further comprising. The method of claim 9,
Measuring the voltage frequency,
When the current flowing to the solenoid forms a closed loop, measuring the voltage frequency of the solenoid,
How to control VFS frequency. The method of claim 10,
The diode includes a plurality of zener diodes connected in parallel,
The plurality of zener diodes operate with different breakdown voltages, respectively
How to control VFS frequency. The method of claim 12,
Operating the plurality of diodes,
Selectively controlling the plurality of diodes such that a ratio of a PWM signal of a current flowing through the solenoid and a dither signal added to the PWM signal reaches a constant value,
How to control VFS frequency. The method of claim 9,
The preset range includes the number of frequencies of the dither signal,
The controlling of the voltage supplied to the solenoid by comparing the ratio may include comparing the ratio with a value obtained by dividing the number of frequencies of the dither signal by the number of rising edges.
How to control VFS frequency.

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