JP2895863B2 - Solenoid valve control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a solenoid valve control device for controlling a linear solenoid valve.

(Prior Art) A conventional solenoid valve control device for controlling a linear solenoid valve of this kind includes, for example, a special power cable and a control command signal line between the solenoid valve and a control command signal output means. Connection.

However, due to the special cable, the material cost and the construction cost are high, especially when the distance between the control command signal output means and the solenoid valve is long. Further, since the number of wires is large, erroneous connection is likely to occur.

For this reason, there is also known an electromagnetic valve control device in which a control command signal is output at a specific frequency or the number of pulses by performing two lines between the control command signal output means and the solenoid valve.

(Problems to be Solved by the Invention) However, when the control command signal output means and the solenoid valve are connected by two wires as described above and controlled at a specific frequency or the number of pulses, the control command When the distance between the signal output means and the solenoid valve is long, there is a problem that a malfunction often occurs due to noise of another power line or the like which is bridged between these two lines.

The present invention has been made in view of the above problems, and material costs,
An object of the present invention is to provide an electromagnetic valve control device that can reduce the construction cost and is less likely to malfunction due to noise or the like.

[Configuration of the invention]

(Means for Solving the Problems) According to a first aspect of the present invention, there is provided an electromagnetic valve control device which outputs a control command signal of a current proportional to a command value, and a control command signal of the control command signal output unit. A two-wire transmission line for supplying power, a current detection means for detecting a control command signal output by the control command signal output means, and a control command for the control command signal output means connected to the two-wire transmission line. A linear solenoid valve having a coil that adjusts the opening of the valve body according to a signal, an opening detection unit that detects the opening of the valve body and outputs an opening signal, and a current that is detected by the current detection unit. Comparing means for comparing the control command signal and the opening signal from the opening detecting means, and converting means for changing the current supplied to the solenoid valve according to the output of the comparing means, wherein the converting means Stored electricity It has a power storage means and a switching element for changing the output of the power storage means, and the switching element is controlled by a chopper control circuit controlled according to the output of the comparison means.

According to a second aspect of the present invention, in the solenoid valve controller according to the first aspect, the power storage means is constituted by a capacitor connected in series to the coil, and between one end of the capacitor and both ends of the coil. Each is provided with a diode for backflow prevention.

According to a third aspect of the present invention, in the solenoid valve control apparatus of the first or second aspect, a constant voltage circuit for supplying a constant voltage is connected to the chopper control circuit.

According to a fourth aspect of the present invention, in the solenoid valve control device according to any one of the first to third aspects, the control command signal output means includes a power semiconductor control element having a signal electrode and a power semiconductor control element. A series circuit of a constant voltage element and a constant current element connected in parallel to each other, and a semiconductor control element connected between the connection point of the constant voltage element and the constant current element and the signal electrode for controlling the power semiconductor control element And control means.

(Operation) The solenoid valve control device of claim 1 outputs a control command signal of a direct current proportional to the command value by the control command signal output means,
This control command signal is sent out along with the supplied electric power through the two-wire transmission line, and the coil adjusts the opening of the valve body according to the control command signal. The control command is detected by the current detecting means, the opening of the valve body of the solenoid valve is detected by the opening detecting means, and the outputs of the current detecting means and the opening detecting means are compared by the comparing means. The current supplied to the solenoid valve is changed in accordance with the output of. Further, the switching element is controlled by a chopper control circuit controlled by the output of the comparison means, and the power stored in the power storage means of the conversion means is varied.

According to a second aspect of the present invention, there is provided the solenoid valve control device according to the first aspect, which supplies the energy stored in the capacitor.

According to a third aspect of the present invention, in the solenoid valve control device according to the first or second aspect, the constant voltage circuit supplies a constant voltage to the chopper control circuit.

According to a fourth aspect of the present invention, there is provided the solenoid valve control device according to any one of the first to third aspects, wherein the control command signal output means controls the power semiconductor control element by the semiconductor control element control means. And a constant current output is supplied by a constant current element.

(Embodiment) Hereinafter, an embodiment of a solenoid valve control device of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a commercial AC power supply, and the commercial AC power supply 1 is connected to a variable DC constant current power supply 2 as control command signal output means. This variable DC constant current power supply 2
Is a high-voltage, large-current type. As shown in FIG. 2, a rectifier circuit 3 for rectifying AC by stepping down with a leakage transformer, for example, is connected to an input terminal of the variable DC constant current power supply 2. I have. The positive output terminal of the rectifier circuit 3 is connected to the positive output terminal of the variable DC constant current power supply 2 via the power semiconductor control element 4, and the negative output terminal of the rectifier circuit 3 is directly connected to the variable DC constant It is connected to the negative output terminal of the current power supply 2. The power semiconductor control element 4 is connected in parallel with a series circuit of a constant current element 5 as constant current means and a constant voltage element 6 made of, for example, a zener diode. Further, a connection point between the constant current element 5 and the constant voltage element 6 as a constant voltage means is connected to a semiconductor element control circuit 7 as a semiconductor element control means.
Are connected to the power semiconductor control element 4.

Then, for example, the command value Ic is supplied to the semiconductor element control circuit 7.
Is applied, the variable DC constant current power supply 2 outputs a control command signal KIc having a magnitude proportional to the command value Ic, for example, 0.4 to 2 A.

The output end of the variable DC constant current power supply 2 is connected to a two-wire transmission line 10 that outputs a control command signal and supplies power. Each of the converters 12 is connected to a positive input terminal or a negative input terminal of the conversion unit 12 via 11.

As shown in FIG. 3, the converter 12 has a positive input terminal directly connected to the positive output terminal, and a negative input terminal connected to the negative output terminal via a capacitor 15 and a diode 16 connected in series as a power storage means. Have been. Also the capacitor
A backflow preventing diode 17 is connected between a connection point of the backflow prevention diode 15 and a connection point of the positive input terminal and the positive output terminal.

Further, a power transistor 19, which is a power semiconductor control element, constitutes a chopper circuit 18 composed of a switching element between both ends of the capacitor 15 and the diode 16.
Are connected. A chopper control circuit for controlling the chopper circuit 18 of the converter 12 is provided between the base and the emitter of the power transistor 19.
20 are connected. Then, when the power transistor 19 of the chopper circuit 18 is turned on, the capacitor 15 is discharged and the load current increases, and when the power transistor 19 is turned off, the capacitor 15 is charged. In other words, if the current width of the chopper circuit 18 is narrow, sufficient energy can be stored in the capacitor 15, so that the load current at the time of discharge increases, and if the current width is wide, energy is stored in the capacitor 15. Therefore, the difference between the load current and the current of the control command signal becomes small, so that the load current decreases. Note that when the conduction width becomes less than a certain value, the capacitor 15 is charged to the maximum value, and an increase in the load current more than a certain value is prevented.

1, a coil 22 of a linear solenoid valve 21 is connected to the output end of the conversion unit 12, and a plunger 23 that operates in accordance with the magnetic force of the coil 22 is provided near the coil 22.
Is provided. The plunger 23 has a valve element 24
Further, a spring 25 biased in a direction to close the valve body 24 is attached. Further, the electromagnetic valve 21 is provided with an opening detector 26 as opening detecting means for detecting the opening of the valve element 24 and outputting an opening signal.

When no load current is supplied to the coil 22, the valve body 24 is closed by the spring 25. When the current I is supplied to the coil 22, the force acting on the plunger 23 overcomes the force of the spring 25, and the valve body 24 opens.

The opening detector 26 is provided close to the conversion unit 12 and the chopper control circuit 20 in order to make it less susceptible to disturbance, and is also provided close to the feedback circuit 31 together with the current detection resistor 11. Connected, the feedback circuit 31 has an amplification unit 32 as comparison means,
This amplifier 32 is connected to the chopper control circuit 20.
The amplifier 32 of the feedback circuit 31 compares the control command signal of the current detection resistor 11 with the opening signal of the opening detector 26, outputs a feedback signal, and outputs the feedback signal.
Is controlled.

Further, a constant voltage circuit 33 is connected to the two-wire transmission line 10. As shown in FIG. 4, the constant voltage circuit 33 includes a collector of a transistor 34 of a high voltage high gain semiconductor device at a positive input terminal, an emitter at a positive output terminal, and a constant voltage device at a negative input terminal and a negative output terminal. The base of the transistor 34 is connected via a zener diode 35 as a reference, and a constant current element 36 is connected between the collector and the base of the transistor 34.

 Next, the operation of the above embodiment will be described.

First, when the command value Ic is given, the variable DC constant current power supply 2
Outputs a control command signal KIc proportional to the command value Ic, and supplies electric power to the converter 12 along with the control command signal KIc via the two-wire transmission line 10.

Then, the coil 22 is driven by the current of the control command signal KIc.
Moves the plunger 23 and opens the valve body 24. At this time, the opening degree detector 26 detects the opening degree of the valve body 24, and this opening degree detector
The opening detection signal detected at 26 and the control command signal detected by the current detection resistor 11 are compared by the amplifier 32 of the feedback circuit 31, and from the opening indicated by the control command signal KIc,
When the actual opening of the valve body 24 detected by the opening detector 26 is narrow, the flow width of the chopper of the chopper control circuit 20 is reduced, and the discharge amount is increased by increasing the charging voltage of the capacitor 15. By increasing the current supplied to the coil 22, the opening of the valve body 24 is increased. Conversely, when the actual opening of the valve body 24 detected by the opening detector 26 is wider than the opening indicated by the control command signal KIc, the chopper control circuit 20 widens the flow width of the chopper, and The amount of discharge is reduced by reducing the charge voltage of the valve 15, the current supplied to the coil 22 is reduced, and the opening of the valve body 24 is reduced. Then, the flow width of the chopper is controlled so that the opening degree indicated by the control command signal is equal to the actual opening degree of the valve element 24 detected by the opening degree detector 26, and the chopper flow rate corresponds to the command value Ic. So that the valve body 24 fits the position.

Further, even if the load changes greatly and a large voltage fluctuation occurs in the two-wire transmission line 10, the constant voltage circuit 33 supplies a stable voltage to the chopper control circuit 20 and the feedback circuit 31.

Furthermore, even if noise is added to the two-wire transmission line 10, the noise is generally in the form of an AC or high-frequency pulse, so the average value is zero, and the DC of the control command signal is not affected as noise.

Next, another embodiment of the converter 12 will be described with reference to FIG.

This is done by coiling a capacitor 15 as power storage means.
22 is connected in parallel. A diode 16 is connected between the positive input terminal and the positive output terminal of the conversion unit 12, a capacitor 15 and a diode 17 are connected between the positive output terminal and the negative output terminal, and a transistor 19 is connected to the positive input terminal and the negative input terminal. Are connected to each other, and a chopper control circuit 20 is connected between the base and the emitter of the transistor 19.

The chopper control circuit 20 controls the transistor 19, as in the case of the converter 12 shown in FIG.

Further, power storage means 15 is not limited to a capacitor, and may use a reactor.

〔The invention's effect〕

According to the invention of claim 1, the opening of the valve body is adjusted by the control command signal from the two-wire transmission line, and the control command signal detected by the current detecting means and the opening signal from the opening detecting means are adjusted. In comparison, since the load current flowing through the coil is controlled by the conversion means, material costs and construction costs can be reduced, and the operation can be reliably performed without causing malfunction. In addition, since a power storage means is provided to store energy, stable operation can be performed.

According to the second aspect of the present invention, since the amount of energy stored in the capacitor is changed, necessary electric power can be secured even when the voltage fluctuates due to a load fluctuation or the like.

According to the third aspect of the present invention, since the constant voltage circuit is connected to the chopper control circuit, the chopper control circuit can be reliably operated.

According to the fourth aspect of the invention, the power semiconductor element is controlled by the semiconductor control element control means, and a constant current output is supplied by the constant voltage element and the constant current element, so that a stable operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a solenoid valve control device of the present invention, FIG. 2 is a block diagram showing a variable DC constant current power supply of the above, FIG. 3 is a block diagram showing a conversion unit of the same, FIG. FIG. 5 is a block diagram showing a constant voltage circuit, and FIG. 5 is a block diagram showing a conversion unit of another embodiment. 2. Variable DC constant current power supply as control command signal output means, 4. Semiconductor control element for power, 5. Constant current element as constant current means, 6. Constant voltage element as constant current means, 7 …………………………………………………………………………………………………………………………………………………………………………………………. … Diode, 17… Diode, 18… Chopper circuit composed of switching elements, 20… Chopper control circuit, 21… Solenoid valve, 22… Coil, 24… Valve body, 26… Open An opening detector as a degree detecting means, an amplifying section as a comparing means, and a constant voltage circuit.

Claims (4)

(57) [Claims] 1. A control command signal output means for outputting a control command signal of a current proportional to a command value; a two-wire transmission line for supplying a control command signal and power for the control command signal output means; A current detecting means for detecting a control command signal output from the output means; and a linear connected to the two-wire transmission line, the coil having a coil for adjusting an opening degree of the valve according to a control command signal of the control command signal output means. An electromagnetic valve, an opening detection means for detecting an opening of the valve body and outputting an opening signal, a control command signal detected by the current detection means and an opening signal from the opening detection means And a converting means for changing a current supplied to the solenoid valve according to an output of the comparing means. The converting means comprises: a power storing means for storing power; and an output from the power storing means. And a switching element for changing the switching element, wherein the switching element is controlled by a chopper control circuit controlled in accordance with an output of the comparing means. 2. The power storage means comprises a capacitor connected in series to a coil, and a diode for preventing backflow is provided between one end of the capacitor and both ends of the coil. Item 2. The solenoid valve control device according to Item 1. 3. The solenoid valve control device according to claim 1, wherein a constant voltage circuit for supplying a constant voltage is connected to the chopper control circuit. 4. The control command signal output means includes: a power semiconductor control element having a signal electrode; a series circuit of a constant voltage element and a constant current element connected in parallel to the power semiconductor control element; 4. A semiconductor control element control means connected between a connection point of a constant voltage element and a constant current element and the signal electrode for controlling the power semiconductor control element. Solenoid valve control device.