JPS60220911A - Control device for solenoid driving current - Google Patents

Abstract

PURPOSE:To enable to hold constant the holding current without being subjected to the effect of the internal resistance due to the temperature rise of the solenoid and the effect of the fluctuation of the driving voltage by a method wherein the solenoid driving current is controlled by a magnetic flux signal, which is sent from the magnetic flux density sensor whereby the magnetic flux density directly detected. CONSTITUTION:A signal P10, which functions as a digital magnetic flux signal, is inputted in a microprocessor 14 by a magnetic flux signal Bi, which is sent from a magnetroelectric conversion element 9 whereby a magnetic flux density Bi is directly detected and when the magnetic flux density Bi reached a reference value (maximum magnetic flux BM) needed for actuating the solenoid, the microprocessor 14 makes the magnetic flux Bi reduce to a prescribed holding magnetic flux BH. Base current runs on the side of base of a driving transistor Tr16, which makes an output signal P20 to function as ON and OFF signals output to the Tr16 of a power circuit 15 so that his holding magnetic flux BH becomes constant and solenoid driving current Ci is flowed to an exciting coil 12. The holding current can be always held in a constant condition by such a way without being subjected to the effect of the internal resistance due to the temperature rise of the solenoid and the effect of the voltage fluctuation of the driving voltage by controlling the driving current, which is flowed from the side of the solenoid power source. As a result, the solinoid can be stably actuated by such a control.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a solenoid drive current control device jδ used for solenoid valves, solenoid switches, and the like.

(Prior Art) As a conventional solenoid drive current control device, for example, a device as described in Japanese Patent Application Laid-open No. 15165/1984 is known.

This conventional device inserts a microresistance in series with the solenoid, and uses this terminal voltage difference as a current feedback signal to control the drive current flowing through the solenoid.It is used as a means to determine when the solenoid has completed operation. ,
This was done by allowing an excessive current several times the rated value to flow only at the beginning of drive.

However, in such conventional devices, since the drive current is controlled by a terminal voltage difference of a minute resistance, it is affected by internal resistance due to temperature rise of the solenoid and voltage fluctuations in the drive voltage. This was unavoidable, causing variations in the holding current and making the solenoid disconnection time inconsistent.

In addition, because the determination of whether the solenoid has completed its operation is made by passing an excessive current in advance, more current than necessary continues to flow even after the solenoid has completed its operation, making it impossible to significantly reduce power consumption. It was something.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and its purpose is to be able to stably control the operation of a solenoid, and to reduce power consumption. An object of the present invention is to provide a solenoid drive current control device that can significantly reduce the amount of current.

(Structure of the Invention) That is, in order to achieve the above-mentioned object, the present invention provides a magnetic flux density sensor that is disposed in a magnetic path generated by an excitation coil of a solenoid to directly detect magnetic flux density and output a magnetic flux signal; The magnetic flux signal from the magnetic flux density sensor is input, and when the magnetic flux reaches the reference value required to operate the slide/id, the magnetic flux is reduced to a predetermined holding magnetic flux, and this holding magnetic flux is kept constant. A drive current control means for controlling a solenoid drive current is provided.

(Effects of the Invention) Therefore, in the solenoid drive current control device of the present invention, the solenoid drive current is controlled by the magnetic flux signal from the magnetic flux density sensor that directly detects the magnetic flux density as described above. The holding current can be kept constant at all times without being affected by internal resistance due to temperature rise of the solenoid or voltage fluctuations of the drive voltage, and stable solenoid operation control can be performed.

In addition, the completion of solenoid operation is determined by the magnetic flux reaching the reference value required to operate the solenoid, and the drive current is reduced to the holding current immediately after that determination, which reduces power consumption. There is no waste, and power consumption can be significantly reduced.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a solenoid current control device for a solenoid valve will be taken as an example.

First, the configuration of the embodiment device will be explained with reference to FIGS. 1 to 6.

S is a solenoid part of a solenoid valve, and this solenoid part S includes an outer yoke 1, an excitation coil 2, a coil pobbin 3, an inner yoke 4, a non-magnetic body 5, and a fixed side plunger 6.
, a sleeve 7 and a movable plunger 8.

The magnetic path M is formed in a closed loop by the inner yoke 4, the fixed plunger 6, the sleeve 7, and the movable plunger 8, as shown in FIG.

Reference numeral 9 denotes a magnetoelectric conversion element as a magnetic flux density sensor, which is disposed on the fixed plunger 6 so as to be perpendicular to the magnetic flux direction of the magnetic path M, and at a position where it can sufficiently withstand the impact from the movable plunger 8. It detects the magnetic flux density Bi of the magnetic path M and outputs a magnetic flux signal (Bi).

In addition, considering the length of the magnetic path M, the length δ of the air gap 10 between both plungers 6.8, the magnetic permeability p of the magnetic path M, and the number of coil turns N, the magnetic flux passing inside the magnetic path M and the magnetic flux of the air gap 10 are Assuming that there is no leakage of magnetic flux, the magnetic flux density Bi in the air gap 10 is given by the following equation.

Bi=NI/(δ/ru0+(text-δ)/ru) Therefore, the excitation current of the excitation coil 2 and the magnetic flux density Bi of the magnetic path are the fourth
As shown in the figure, there is a proportional relationship, indicating that the magnetic flux density Bi can be used as control data for the excitation current I (solenoid drive current).

In addition, Fig. 5 shows Ga-As, a typical magnetoelectric conversion element.
This figure shows the relationship between the magnetic flux density and Hall voltage of the Hall element, which is preferable because the two are in a proportional relationship and the temperature characteristics are stable.

11 is a signal amplification conversion circuit, and the magnetoelectric conversion element 9
Amplifier 12 and A/D converter 1
It is composed of 3.

Note that the signal amplification conversion circuit 11 outputs a signal (PIO) as a digital magnetic flux signal to the microprocessor 1, which will be described later.
Output to 4.

14 is a microprocessor as a drive current control means, and the signal (PIO) as the digital magnetic flux signal is
is input, and when the magnetic flux Bf reaches the reference value (maximum magnetic flux BM) required to operate the solenoid, the magnetic flux density Bi
is reduced to a predetermined holding magnetic flux BH, and this holding magnetic flux BH
power supply circuit 1, which will be described later, from the output terminal so that
5 outputs an output signal (P2O) as an ON/OFF signal to the drive transistor 16 of the CPU, R
It includes an AM, a ROM, and an I10 port, and a control program shown in the flowchart of FIG. 7 is written in advance in the ROM.

15 is a power supply circuit, and the microprocessor 14
input the output signal (P20) from the
This is a circuit that energizes in response to P20), and when the output signal (P20) is ON, a base current flows to the base side of the drive transistor 16, and a solenoid drive current C1 flows to the excitation coil 2.

The power supply circuit 15 includes the drive transistor 16 and a flywheel diode 17 for absorbing coil surge.
, a transistor protection capacitor 18 , and a transistor protection Zener diode 19 .

Reference numeral 20 denotes a power switch that applies the voltage from the power source 21 to the microprocessor 14 as a solenoid command signal (NF).

In addition, what is indicated by 22 in the figure is the wiring port for the excitation coil, 2
3 is a wiring boat for the magnetoelectric transducer.

Next, the operation will be explained with reference to FIGS. 7 to 9.

First, in judgment 201 of the microprocessor 14, it is determined whether the solenoid command signal (NF) has been turned ON (step 2 in FIG. 8(C)).

If it is ON, the process proceeds to process 202, where the output signal (P2O) of the microprocessor 14 is turned on, and the process further proceeds to process 203.

In this process 203, the solenoid command signal (NF) is
After reaching N, the magnetic flux density Bi, which increases with time, is read by the magnetic flux signal (Bi) from the magnetoelectric transducer 9 (FIG. 8(C)--step 2).

Note that the magnetic flux signal actually input to the microprocessor 14 is converted into a magnetic flux signal (Bi) by the amplification conversion circuit 11.
The input signal (P
IO).

Decision 204 then checks whether the flux signal (Bi) has reached the maximum flux signal (BM) required to actuate the solenoid and determines whether the flux signal (Bi) has reached the maximum flux signal (BM). If so, it is determined that the solenoid has finished driving, and the output signal (P
2O) is turned off in process 205 (Fig. 8(C)-■
process).

Then, in process 206, the magnetic flux signal (Bi) after reaching the maximum magnetic flux signal (BM) is read (Fig. 8(C)-■
step), and in judgment 207, the magnetic flux signal (Bi) is the holding magnetic flux signal (B
H) Determine whether or not it is greater than or equal to H).

Then, when the magnetic flux signal (Bi) falls to the level of the retained magnetic flux signal (BH), the process proceeds to the ON10 F F control unit 208, and if the magnetic flux signal (Bi) is larger than the retained magnetic flux signal (BH), the process proceeds to process 206. Go back and continue reading the magnetic flux signal (Bi) again.

Then, when the magnetic flux signal (Bi)≦the retained magnetic flux signal (BH), the ON10 FF control unit 208 starts the ON10 FF control of the solenoid.

In the example, the ON time of the solenoid is constant (tl).
By controlling the length of the OFF time, the magnetic flux is 4g (Bi).
is set to the level of the holding magnetic flux signal (BH) (see Fig. 9).

The ON10 F F control will be explained below with reference to FIG. 7. In process 209, the magnetic flux signal (Bi) is
H), the output signal (P20) of the microprocessor 14 is turned ON to increase the magnetic flux signal (Bi).
20) ON time is managed by a timer section 210,
The ON state is maintained for a certain period of time (tl), and then processing 211
to turn off the output signal (P2O).

Furthermore, in process 212, similarly to process 206, the magnetic flux signal (Bi) continues to be read until the magnetic flux signal (Bi) falls to the level of the retained magnetic flux signal (BH), and in judgment 213, the magnetic flux signal (Bi) is determined to be the retained magnetic flux signal ( If it is determined that the solenoid command signal (NF) has fallen to BH), the process proceeds to decision 214, where it is determined whether the solenoid command signal (NF) shown in FIG. 8(A) is ON, and if it is OFF, this routine ends.

Also, in judgment 214, the solenoid command signal (NF) is turned on.
If it is, the process returns to step 209 and the output signal (P20) of the microprocessor 14 is turned on.

Incidentally, in the judgment 201, the deviation/idle command signal (N
If F) is not ON, the process proceeds to step 215, where the output signal (
P2O) is turned off, and this routine ends.

Therefore, in the solenoid drive current control device of this embodiment, the solenoid part electrodynamic fftci is controlled by the magnetic flux signal (Bi) from the magnetoelectric conversion element 9 that directly detects the magnetic flux density Bi as described above. Therefore, the holding current can be kept constant at all times without being affected by internal resistance due to temperature rise of the solenoid or voltage fluctuations of the drive voltage, which is the case with drive current control from the solenoid power supply side, resulting in a stable solenoid. The operation can be controlled.

In addition, the completion of solenoid operation is determined by the magnetic flux reaching the reference value required to operate the solenoid, and the drive current is reduced to the holding current immediately after that determination, which reduces power consumption. There is no waste, and power consumption can be significantly reduced.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a solenoid part of a solenoid valve to which a solenoid drive current control device according to an embodiment of the present invention is applied, FIG. 2 is a sectional view showing a fixed-side plunger of the solenoid part, and FIG. 3 is a sectional view showing the fixed-side plunger of the solenoid part. A side view of the plunger, FIG. 4 is a relationship diagram between exciting current and air gap magnetic flux density, FIG. 5 is a relationship diagram between air gap magnetic flux density and Hall voltage, and FIG. 6 is an overall diagram showing the control device of the embodiment. FIG. 7 is an operation flowchart of the micropro sensor of the embodiment device; FIG. 8(A);
(B) and (C) are comparison diagrams of the solenoid command signal, output signal, and magnetic flux signal, and FIG. 9 (A). (B) is a comparison diagram showing the control state of the holding magnetic flux signal. S... Solenoid part 2... Excitation coil M... Magnetic path Bi... Magnetic flux density (Bi)'... Magnetic flux signal 9... Magnetoelectric conversion element (magnetic flux density sensor) 14... Micro Processor (drive current control means) Ci... Solenoid drive current Figure 1 Figure 2 Figure 3 Dan

Claims (1)

[Claims] 1) A magnetic flux density sensor that is placed in the magnetic path generated by the excitation coil of the thread/id and directly detects the magnetic flux density and outputs a magnetic flux signal, and a magnetic flux density sensor that inputs the magnetic flux signal from the magnetic flux density sensor, and and drive current control means for reducing the magnetic flux to a predetermined holding magnetic flux when the reference value necessary for operating the solenoid is controlled, and controlling the solenoid drive current so that the holding magnetic flux is constant. Features a solenoid drive current control device.