JPS60104874A - Control device of proportional solenoid valve - Google Patents

Abstract

PURPOSE:To prevent a valve from its irregular vibration and obtain a stable flow characteristic, by connecting the output terminal of a circuit, which adds signals of a dither generating circuit and a current control circuit, to the base terminal of a transistor parallelly connecting a capacitor. CONSTITUTION:A coil 11 of a proportional solenoid valve, transistor amplifier 12 and a resistor 13 are connected in series to a DC power supply 10. A diode 14 and a capacitor 15 are respectively connected in parallel to the valve coil 11 and the transistor 12. Further a dither generating circuit 16, current control circuit 17 and an adder circuit 18 are connected so as to input an output of the circuit 16, 17 to the circuit 18, still further an output terminal of the adder circuit 18 is connected to a base terminal of the transistor 12. By such circuit constitution, a current of the valve coil is shaped to almost a trapezoidal waveform with gentle leading and trailing edges, never inducing vibration of the valve.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electromagnetic proportional valve control device for controlling a fluid flow 111 according to current, and in particular to a solenoid proportional valve control device that controls a fluid flow 111 with small and good hysteresis and stable flow characteristics. The present invention relates to a configuration of a control device that can be operated.

Problems with the structure of the conventional example The electromagnetic proportional valve is used in gas water heaters, gas heaters, gas cookers, etc. to control the amount of gas supplied to the burner in response to the temperature load to be controlled. In the electromagnetic plunger sliding type valve, when the valve body starts to move, it does not move until a force is generated that overcomes the static friction force, and when the valve body is adjusted to the correct size, it stops when the dynamic friction force and driving force match. Therefore, accurate and highly reproducible flow rate control of the proportional valve coil current cannot be performed due to errors commensurate with the frictional force and hysteresis due to residual magnetism in the plunger and yoke.

Therefore, in order to improve the hysteresis characteristics, the following control device is conventionally known.

The control circuit in this case is shown in FIG.
The current is full-wave rectified by a rectifier 2, and a pulsating direct current is passed through a series circuit consisting of a coil 3 of an electromagnetic proportional valve, a transistor amplifier 4, and a resistor 5, and a predetermined control is performed while slightly vibrating the plunger. This is what I did.

In order to change the average value of the current flowing through the proportional valve coil 3, as shown in Figure 2, the setting level is adjusted from the maximum current value (see Figure 2 (a)) by directly switching the full-wave rectified direct current. , -'' The current is controlled within the range of the desired value obtained by cutting the second wave height (see Figure 2, middle) and (c)), and this control is performed steplessly by the current adjustment circuit 6. It is accomplished according to the purpose.

In addition to this, there is also a type in which the current is controlled by a phase control method using Cyrisk.

According to the conventional power formula, the teaser (output current waveform) effect is weakened, making it difficult to achieve the initial purpose, and this drawback is particularly noticeable in the low current range. However, the performance of the electromagnetic proportional valve was not fully demonstrated.

In order to compensate for the above drawbacks, the following control device is known as another conventional example.

In this case, the ti control circuit t:r is shown in Figure 3.The transistor amplifier 4 and the coil 3 of the electromagnetic proportional valve are connected in series to the DC electric gap 7, and a square wave signal is generated at the base terminal of the transistor amplifier 4. In the configuration in which the circuit 8 is connected, the square wave signal generating circuit 8 has a constant peak value (amplitude) and period of the square wave as shown in Fig. 4), (e), and (e), and has a constant on and off state. By changing the time ratio (duty), output signals with different average voltage values of 7 are output. The reason why a resistor 5 and a diode 9 are connected in series in parallel with the electromagnetic proportional valve 3 is to absorb the surge voltage of the valve coil 3.

In the conventional example described in ``2'', an intermittent square wave voltage is applied to the coil 3 of the electromagnetic proportional valve, and the voltage and current waveforms of the valve coil 3 rise and fall rapidly as shown in Fig. 5. This induces irregular vibrations in the plunger and valve body of the electromagnetic proportional valve, causing the flow rate characteristics to deviate from the normal flow characteristics (G) as shown in Figure 6 and become disordered flow characteristics as shown in (A). However, there was a problem in that so-called characteristic disturbances were likely to occur. As with this conventional method, under the conditions of constant period and constant amplitude,
If an attempt is made to make the rise and fall gradual, the period must be lengthened, and then, as in the first conventional example, a sufficient dither effect cannot be obtained. The DC current that is not completely smoothed by rectifying the shattered commercial power supply and has pulsating components left behind is transferred to the electromagnetic proportional valve coil 3 and the transistor amplifier 4.
There is also a known method in which the pulsating flow component is used as a dither effect by connecting C in series with the pulsating flow frequency.
The Hz was also limited to 60 Hz, and it was not possible to obtain a sufficient dither effect.

OBJECT OF THE INVENTION The present invention solves the problems of the conventional art, and provides a stable/coupled one characteristic with good hysteresis, which can obtain a sufficient dither effect, is less likely to cause irregular non-vibration OJ, and has good hysteresis. 1till 伶11
The purpose is to obtain equipment.

Structure of the Invention In order to achieve this objective, the present invention connects a valve coil and a transistor amplifier in series to a DC power source, and
A dither generation circuit that generates a voltage waveform with an amplitude, a current control circuit that changes the DC voltage level, and
It has an adder circuit that adds the signals of the IL disa generating circuit and the current control circuit, and the output terminal of the adder circuit is connected to [j1].
A capacitor is connected in parallel with the base terminal of the transistor amplifier described above and the transistor amplifier described above. When changing the average current level flowing through the electromagnetic proportional valve coil with this configuration,
The current in the valve coil has a dither effect '2, the most preferred -'A
It acts so that the current waveform has an E period and amplitude and a gradual rise and fall.

Description of examples 1.1 An embodiment of the present invention will be described below with reference to FIG.

In FIG. 7, the coil 11 of the electromagnetic proportional valve is connected to the DC power supply 10.
A transistor amplifier 12 and a resistor 13 are connected in series, a diode 14 is connected in parallel with the valve coil 11, a capacitor 15 is connected in parallel with the transistor 12, and the output of a dither generating circuit 16 and a current control circuit 17 is connected in series. is connected to be input to the adder circuit 18, and the output terminal of the adder circuit 18 is connected to the base terminal of the transistor 120.

The voltage waveform generated by the dither generation circuit 16 in the second phase is set to an optimum constant period constant amplitude that can reduce hysteresis for the electromagnetic proportional valve and does not cause undesirable valve vibration. The signal and the DC voltage signal of the current control circuit 17 are added by the adder circuit 18, and the transistor 120 base current waveform is divided into three periods and amplitudes, as shown in FIG. acts so that it does not change and remains constant.

At this time, the current waveform of the coil 11 of the electromagnetic proportional valve acts in a substantially trapezoidal waveform as shown in FIG.

To explain the reason, if the base current of the transistor 12 to be disconnected suddenly falls, it can be thought of as if the electric resistance between the collector emitter of the transformer 12 suddenly increases at 1) °C. The collector current of 12 suddenly decreases. However, since the capacitor 15 is connected in parallel with the transistor 12, the capacitor 15 is charged and this charging current flows through the valve coil 11. At this time, as the capacitor 15 is being charged, the charging current gradually decreases. From the above, when the base current suddenly falls, the current in the valve coil 11 will gradually decrease. Conversely, when the base current rises or falls, the electric charge charged in the capacitor 15 is discharged through the transistor 12, so the current in the valve coil 11 increases as the capacitor discharge current decreases, so it gradually increases. I will do it. Therefore, the current in the coil 11 of the electromagnetic proportional valve changes in a substantially trapezoidal waveform as shown in FIG. This has the effect of obtaining stable proportional flow characteristics with small hysteresis.

Effects of the Invention As described above, the electromagnetic proportional valve control device of the present invention provides the following effects.

(1) The signals from the teaser generation circuit that generates a waveform with a constant period and amplitude and the current control circuit are added by an adder circuit, and the result is input to the transistor base terminal, and a capacitor is connected in parallel with the transistor. The current in the valve coil acts in a roughly trapezoidal waveform with gentle rises and falls, and while exhibiting an effective teaser effect, it does not induce undesirable valve vibration, resulting in stable flow characteristics with small and good hysteresis. There is an effect that can be achieved by operating a solenoid proportional valve.

(2) The teaser waveform, frequency, and amplitude are calculated by adding the teaser signal generated by the teaser generation circuit and the DC signal generated by the current control circuit, and manually inputting the signal to the transistor base terminal connected to the valve coils in series. It can be set arbitrarily and in the most convenient manner, and can be adapted to each type of electromagnetic proportional valve.

Due to the shape and weight of the solenoid proportional valve's first part and valve body] 1), it has the most teaser effect! : The waveform, period, and amplitude that can exhibit this effect often have different conditions. Sword/
This inconvenient non-performance:! ilJ (!l-The same applies to the conditions that occur, according to the configuration of the present invention described in 1-1)1. This makes it possible to create them under the most suitable conditions.

(3) From low current to 11-" current 1-C1 is a method that always operates with a dither waveform with a constant periodic amplitude. Even if a constant dither effect is always optimal, a stable 4:' characteristic can always be obtained.

[Brief explanation of the drawing]

Fig. 1 is a basic circuit diagram showing an example of a conventional electromagnetic proportional valve control device, Fig. 2 (a) to (c) are current waveform diagrams of the valve coil according to the device shown in Fig. 1, and Fig. 3 is another example. A basic circuit diagram showing an example of a conventional electromagnetic proportional valve control device, Fig. 4) to (f) are output waveform diagrams of the square wave generation circuit of the device shown in Fig. 3, and Fig. FIG. 6 is a diagram of the voltage/current waveform diagram of the valve coil of the device shown in FIG. The basic circuit diagram shown in FIG. 8 (d) is a transisk base current waveform diagram of the device shown in FIG. 7, and FIG. 9 is a valve coil current waveform diagram of the device shown in FIG. 7. 10. DC power supply; 11 valve coil, 12 transistor amplifier, 15 capacitor, 16... teaser generation circuit,
17 Current control circuit, 18... Addition circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 (A) (Rono (C) Figure 3 Figure 4 (2) (E) (Heno average current I →

Claims (1)

[Claims] A dither generation circuit that connects a valve coil and a transistor amplifier in series to a DC power supply to generate a voltage waveform with a constant period and amplitude, and a current control circuit that varies the meandering voltage level; 1]
[1] An adder circuit for adding the signals of the dither generation circuit and the current control circuit described in (■), and an output terminal of the adder circuit connected to the base terminal of the transistor amplifier;
) An electromagnetic proportional valve control device comprising a transistor amplifier and a capacitor connected in parallel.