JPS5998215A - Solenoid driving circuit - Google Patents

Abstract

PURPOSE:To control optionally an electromagnetic force in accordance with the magnitude of a command signal, by connecting a control circuit which controls the current flowed to a solenoid coil so that this current has a value corresponding to the command signal. CONSTITUTION:A rectifying circuit 11 reactifies the AC power from a power source 10, and the output is supplied to a solenoid coil 13, a current detecting member 16 which detects the current flowed to the coil 13 and a transistor TR17 which controls the current flowed to the coil 13. Meanwhile, the command signal is given to an input terminal 19 of a control circuit 14, and the pulse width of the output signal of a comparing circuit 33 is changed in accordance with the magnitude of the command signal, and the pulse width of the output signal of a comparing circuit 29 is changed in accordance with this change. The output of the circut 29 controls the conduction of the TR17, and as the result, the power supply time to the coil 13 is controlled to a short, middle, or long time, and the current value flowed to the coil 13 is small, middle, or large. Thus, an electromagnetic force corresponding to the command signal is generated by the coil 13.

Description

[Detailed Description of the Invention] This invention is an electromagnetic device that uses electromagnetic force to perform mechanical operations, such as an electromagnetic proportional valve, in which a current is passed through a solenoid coil to generate electromagnetic force. The present invention relates to a solenoid drive circuit that does this.

The purpose is to provide a solenoid drive circuit that can arbitrarily control the electromagnetic force according to the magnitude of a command signal.

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, reference numeral 10 indicates a power source. This power supply 10
is a commercial AC power source generally used in factories and other places. A rectifier circuit 11 whose input side (AC side) is connected to the power source IO rectifies the AC power from the power source 10 and outputs it. As this rectifier circuit, for example, a bridge type aftereffect rectifier circuit is used. On the output side (DC side) of the rectifier circuit H, there is a solenoid coil U and the solenoid coil U.
A current detection member 16 for detecting the current flowing through the solenoid coil and a transistor 17 for controlling the current flowing through the solenoid coil are connected in series. The above current detection member 1
As the resistor 6, for example, a resistor inserted in the above-mentioned series connection circuit is used. A well-known surge absorption circuit Nagi is connected to the coiled current detection member 16. On the other hand, 14 indicates a control circuit. This includes a front stage control circuit 14a having members indicated by symbols 4 to 2, and a rear stage control circuit 14b having members indicated by symbols 4 to 1 and A to I.
Moreover, the output terminal of the preceding stage circuit 14 a and the subsequent stage circuit 14
B is connected to the input end by an air router M that transmits signals but is electrically insulated from each other. The input terminal of the preceding circuit 14a is connected to a command signal input terminal +19 provided for inputting a command signal for controlling the current flowing through the solenoid coil 13. Further, the output terminal of the circuit 14b in the subsequent stage is the control terminal of the transistor 17 (
base) 17a. Indicates a transformer, which has a secondary winding 9Qa connected to the power source 10 and three secondary windings 1J20b, 20c, and 20d. 2 each
The secondary windings are insulated from each other and from the above/next winding. Reference numerals 12a and 12b are power supply circuits, respectively, which convert low-voltage alternating current from a transformer into direct current and supply it as operating power to the front-stage and rear-stage control circuits 14a and 14b, respectively.

Next, the operation of the above configuration will be explained. Incidentally, since the waveforms of the output signals of each of the above-mentioned members are shown in FIGS. 2 to 3, please refer to them together in the explanation of the operation.

In each waveform diagram, the same reference numerals as those of each member are used to indicate which member's output signal the waveform corresponds to.

Further, the voltage applied to the solenoid coil U is V, and the current flowing therein is indicated by t.

First, in the subsequent control circuit 14b, the alternating current signal appearing in the 22nd winding 20b of the transformer is rectified by the full-wave rectified signal B. The full-wave rectified signal is input to the comparison circuit η. Further, a part of the output signal of the aftermath rectifier circuit 21 is inputted to the average value circuit S, and the average value signal outputted from the circuit array is also inputted to the comparison circuit η. Then, the comparator circuit ρ outputs a square wave signal that becomes positive only during a time period in which the voltage value of the aftereffect rectified signal exceeds the voltage value of the average value signal. This signal is transmitted to the integrating circuit section via the diode driver. The integrating circuit δ integrates the charge supplied from the constant current circuit during the time period when the output voltage of the comparator circuit ρ is positive, and discharges the integrated charge through the diode during other time periods. Therefore, the output signal of the integrating circuit 6 has a waveform as shown by δ in FIG. The output signal of the comparator circuit I is also sent to the inverting circuit I. This inversion circuit η inverts the signal from the comparison circuit ρ.

The output signal of the integrating circuit 6 and the output signal of the inverting circuit I are added by an adder circuit, and the output signal is sent to a comparator circuit 4.

On the other hand, in the pre-stage control circuit 14a, the triangular wave signal from the triangular wave oscillation circuit (equipment) and the DC signal from the level shift circuit 31 are input to the adder circuit array and are added together. Note that as the level shift circuit 31, any DC voltage supply circuit or battery can be used. The added signal and the command signal input to the command signal input terminal 19 are input to the comparison circuit Okara, and the illustrated signal is output from the comparison circuit Okara. Note that the triangular wave signal is 7 of the full wave rectified signal.
For example, a signal is used that is repeated so that more than 10 peaks are included within the time of the peak. The output signal of the above comparison circuit array, i.e., the pre-stage system'
The output signal of the 111 circuit 14& is inputted to the smoothing circuit 5 of the subsequent control circuit 14b via an isolator, and is returned to a direct current as shown (a direct current with a voltage value corresponding to the voltage value of the command signal). The isolator (for example, a photocoupler is used (pulse transformers and other devices can also be used).The output signal from the smoothing circuit is input to the error amplification circuit section, where it is corrected as described later, and the output signal from the smoothing circuit is input to the error amplification circuit section. The output signal is input to comparator circuit four.

The comparator circuit 9, which receives the signal from the okara circuit and the signal from the circuit section, outputs a square wave signal that becomes positive only in a time period in which the latter exceeds the former. This signal becomes the output signal of the subsequent stage control circuit 14b.

The above output signal is the control terminal (pace) 1 of transistor ■
Added to 7a. Then, the transistor 17 repeatedly turns on and off in synchronization with the output signal.

As a result, the voltage shown in Figure 2 is applied to the solenoid coil U, and the current shown in i flows.

As a result, the magnetronoid coil is in a state in which energization and de-energization are repeated at short intervals, that is, every half cycle of the AC power from the power source 10, and therefore the electromagnetic device driven by the excitation of this coil is A sufficient dither effect is given to the movable core so that the movable core operates accurately.

Note that the voltage is applied from the rectifier circuit U to the solenoid coil B only in the time zone near the top of the voltage waveform of the output of the rectifier circuit 11. However, due to the presence of the surge absorption circuit, as shown in Figure 2, even at other times, a voltage with a polarity opposite to that of the voltage applied from the rectifier circuit U to the solenoid coil U is applied. .

The same applies to the current t.

When current flows through the solenoid coil U as described above, the current also flows through the current detection member 16, so that member 16 detects the value of the current flowing through the solenoid coil and sends out an output signal corresponding to the value. The output signal is smoothed by the smoothing circuit V in the subsequent control circuit 14b to become a direct current, and sent to the error amplifier circuit A. In the error amplifying circuit section, a well-known error correction for the signal from the circuit section is performed using the output signal from the circuit a.

That is, when the signal value from the circuit V337 is lower than the value corresponding to the signal value from the circuit section, the output signal value of that circuit becomes high, and operates to increase the energization time to the solenoid coil, and vice versa. In such a case, it operates to reduce the energization time. As a result, the current value (average current value) flowing through the solenoid coil becomes a value that accurately corresponds to the command signal.

Next, when operating as described above, if the value of the command signal is small, medium, or large, the states shown in Figures (1), (2), and (8) will occur, respectively. Become.

That is, the pulse width of the output signal of the circuit section changes depending on the magnitude of the value of the command signal, and the output signal value of the circuit section changes accordingly. Accordingly, the output signal value of the circuit changes accordingly, and the pulse width of the output signal of the circuit changes. As a result, the energization time to the solenoid coil is controlled to be short, medium, and long as shown in the figure, and the current value (average current value) flowing through the coil becomes small, medium, and large, respectively. In this way, the electromagnetic force corresponding to the command signal is applied to the coil U.
generated by.

In the case of the above operation, even though the rear-stage control circuit 14b is connected to the power supply 10 via the transistor 17 and the aftereffect rectifier circuit U, the front-stage control circuit 14a is insulated from them through the isolator A. This prevents other equipment connected to the input terminal 19 from being damaged by the high voltage of the power supply IO, or from giving electric shock to workers operating those equipment.

Next, FIG. 5 showing a different embodiment of the present application will be described. This figure shows an example in which the configurations of the energizing circuit for the solenoid coil 13e and the subsequent control circuit 14b are different. That is, in the figure, d is a smoothing circuit that converts the rectified signal into a complete direct current.

Further, C is a sawtooth wave generating circuit.

The device having the above configuration has a waveform state as shown in FIG. 6 in the operating state. That is, the comparison circuit 29e inputs the signal from the sawtooth wave generation circuit and the signal from the error amplification circuit 36e, and outputs a square wave having a waveform as shown in the figure. Accordingly, the transistor 17e repeats conduction and interruption, and as a result, the DC output of the smoothing circuit 41 is interrupted and supplied to the solenoid coil 13e.

In addition, the parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as those in the previous sentence with the letter e, and redundant explanations are omitted. (Also, in the next time and subsequent ones, the same idea will be used sequentially with the alphabet fSg.
. . . are added in order to omit duplicate explanations. ) Next, FIG. 7 shows a further different embodiment of the present application, in which a mechanical operation is detected to obtain a correction signal, and the command signal is corrected using the signal, so that the mechanical operation is converted into a command signal. This example shows how to correctly respond to the following.

In the figure, a plunger is operated by receiving the electromagnetic force of a solenoid coil 13f, and 6 is a valve device whose operation is controlled by a plunger 44, which is interposed in a hydraulic piping. 4
7 is a pressure jump-up, which detects the oil pressure in the piping and outputs a signal corresponding to it. 48 is an inversion circuit, and chrysanthemum is an addition circuit.

In the above configuration, the electric current flowing through the coil 13f generates a stain magnetic force to operate the plunger.

Then, the valve device operates correspondingly, and the pressure in the pipe changes. This change is detected by the pickup C and its output signal is given to the inverting circuit. The inverter circuit inverts the above signal and adds it to the adder circuit.

An adder circuit 49 adds the command signal and the inverted signal. As a result of such an operation, if the oil pressure in the piping is not at a value corresponding to the command signal, a correction for this is performed by the adder circuit. As a result, the oil pressure finally becomes a value that correctly corresponds to the command signal.

Incidentally, the above-mentioned correction may be performed by detecting other mechanical operation, for example, the movement of the plunger with a differential transformer, and adding the output signal of the differential transformer to the above-mentioned inverting circuit.

Next, FIG. r, FIG. 9, and FIG. 1θ respectively show different examples of the circuit from the command signal input terminal to the smoothing circuit in the circuit of FIG. 7 or FIG.

In the example shown in Figure 1, the signal that enters the command signal input terminal 19g is converted by the V-F converter group into an alternating current (pulse) corresponding to the DC voltage value of the command signal, and the alternating current is passed through the 7 Otokagura group. The signal is then transmitted to the F-V converter &, where it is converted back into a DC signal.

Next, in the example of FIG. 9, the input signal causes the light emitting diode group to emit light after passing through the amplifier circuit section. The light is simultaneously received by phototransistors a and 58.

The output of the phototransistor d is fed back to the input side, and is automatically adjusted by the operation of the amplifier circuit so that it is equal to the input signal. Since the related characteristics between the light emitting diode group and the phototransistor S and the related characteristics between the light emitting diode group and the phototransistor block are set to be equal, the phototransistor group outputs a signal that correctly corresponds to the input signal.

Next, in the example of FIG. 10, the excitation coil is excited by the input signal. On the other hand, the excitation coil port magnetically coupled to the coil 61 is excited in a direction to demagnetize the coil 0. Therefore, the Hall element axis magnetically coupled to both coils 63 produces a direction corresponding to the difference in excitation of both coils ω, 63. - The example of the force amplification circuit works so that the direction of the Hall element axis becomes 0, and excites the coil ω. At this time, the excitation of the coil group and the excitation of the coil strip are equal, and the output signal taken out from the coil hammer is equal to the input signal.

As described above, the present invention has the advantage that it is possible to generate electromagnetic force by energizing the Nlenoid coil, and that the electromagnetic force can be used for various purposes.

Furthermore, in that case, by controlling the current control transistor 17 for the coil based on the command signal, the current flowing to the solenoid coil port can be controlled, and the required electromagnetic force can be generated.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a block diagram of a drive circuit, FIGS. 2 to 3 are waveform diagrams for explaining the operation of the circuit in FIG. 1, and FIG. A block diagram showing an example, FIG. 6 is a waveform diagram for explaining the operation of the circuit in FIG. 5, FIG. 7 is a block diagram showing a further different embodiment, and FIGS. (a diagram showing different examples of isolation). 10... Power source, ■... Rectifier circuit, U... Solenoid coil, 14... Control circuit, 19... Command signal input terminal. Figure 1 Figure 3 (1) 37-2 Figure 4 rZ) (3) 1 Glume 14e Figure 6 Figure 8

Claims (1)

[Claims] The AC side of the rectifier circuit is connected to the power source, and the solenoid coil and a transistor that controls the current flowing through the fill are connected to the DC side of the rectifier circuit.
On the other hand, there is a connection between the command signal input terminal into which the command signal is input and the control terminal of the transistor so that the current flowing through the solenoid coil has a value corresponding to the command signal applied to the command signal input terminal. A solenoid drive circuit that connects a control circuit that controls the above transistor.