JPH053757U - Control device for electromagnetic control valve - Google Patents

Abstract

(57) [Abstract] [Purpose] A control device for an electromagnetic control valve having a power supply circuit for step-down rectifying commercial alternating current so that commercial alternating current of different voltage can be used. [Structure] The power supply circuit 4 rectifies and smoothes commercial alternating current into direct current, which is applied to a primary coil 36 of a transformer 37 under the on / off operation of a switching element 35, and in response thereto, a secondary coil 38 of the transformer 37. Is provided with a switching power supply circuit 14 having a control circuit 44 for controlling the on-time of the switching element for rectifying and smoothing the voltage induced in the output and outputting the output voltage from the secondary coil 38 to a constant voltage. Therefore, the switching power supply circuit 14 is configured to perform step-down rectification of commercial AC.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic control valve that performs a valve action according to a current supplied to a solenoid, and relates to a control device for an electromagnetic control valve used to control a current supplied to a solenoid.

[0002]

[Prior Art]

 Such a control device for an electromagnetic control valve generally includes a power transistor connected in series with a solenoid and a drive control circuit for driving the power transistor. The power supply circuit, which serves as a DC power supply for the solenoid and drive control circuit, is configured by stepping down commercial AC by a transformer, rectifying and smoothing it, and then attaching a stabilizing circuit to the solenoid and drive control circuit. DC power is supplied from the circuit.

[0003]

[Problems to be solved by the device]

 By the way, generally, different voltages of 100 V and 200 V are used as commercial alternating current, and different voltages such as 120 V and 240 V are specified for special items such as export. In this way, when the commercial AC voltage changes, the voltage stepped down by the transformer also changes, so it is necessary to change the power supply circuit, such as changing the transformer according to the commercial AC voltage, and in a control device that targets the same electromagnetic control valve. However, there was a problem that it could not be standardized, and it took time and effort in manufacturing and management. The present invention is intended to provide a control device for an electromagnetic control valve, which solves such a problem by enabling commercial AC of different voltage to be stepped down to a constant voltage by a power supply circuit.

[0004]

[Means for Solving the Problems]

 Therefore, the control device of the electromagnetic control valve of the present invention is a DC power source for the power transistor connected in series to the solenoid of the electromagnetic control valve, the drive control circuit for driving the power transistor, and the solenoid and the drive control circuit. A power supply circuit, and a transformer having a primary coil and a secondary coil for stepping down and rectifying commercial alternating current, and a switching element that is connected in series with the primary coil of the transformer and that operates on and off. , A first rectifying and smoothing circuit that rectifies and smoothes commercial alternating current and applies it to the primary coil of the transformer via a switching element, and rectifies and smoothes the induced voltage to the secondary coil connected to the secondary coil of the transformer. And a control circuit that controls the on-time of the switching element to make the output voltage from the second rectification and smoothing circuit a constant voltage. It was composed as comprising a switching power supply circuit having.

[0005]

[Action]

 According to such a configuration of the present invention, in the switching power supply circuit of the power supply circuit, the commercial alternating current is converted into direct current by the first rectifying and smoothing circuit, and this is intermittently applied to the primary coil of the transistor by the on / off operation of the switching element. Then, in response to this, a reduced induced voltage is generated in the secondary coil, and this induced voltage is converted into a direct current by the second rectifying and smoothing circuit and output. The on-time during the on / off operation of the switching element is controlled by the control circuit so as to make this output voltage a constant voltage. Therefore, for example, if the commercial AC voltage is high and the output voltage is correspondingly high, the switching element will turn on. When the time is shortened and the output voltage rise is suppressed, and when the commercial AC voltage is low and the output voltage is going to decrease accordingly, the on time of the switching element becomes long and the output voltage drop is suppressed. Thus, a constant output voltage can be obtained even if the commercial AC voltage changes. Therefore, it is not necessary to change the power supply circuit even if the commercial AC voltage used changes.

[0006]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a control device A for an electromagnetic control valve. The control device A includes a power transistor 2 connected in series with a solenoid 1 of an electromagnetic control valve (not shown), and a drive control circuit 3 for driving a power transistor 2. The power supply circuit 4 serves as a direct current power supply for the solenoid 1 and the drive control circuit 3. As is well known, the electromagnetic control valve performs a valve action so as to obtain a pressure and a flow rate according to the electric current supplied to the solenoid.

A current detection resistor 5 is connected in series to the solenoid 1, and a flywheel diode 6 is connected in parallel with the solenoid 1 and the current detection resistor 5. The drive control circuit 3 will be described. Reference numeral 7 is a command input terminal to which a command voltage of a current to be applied to the solenoid 1 is input, and 8 is an amplifier composed of an operational amplifier for amplifying this command voltage. The output voltage of the amplifier 8 is the dither signal from the oscillator 9. Is inputted to one input terminal of the comparator 10. The comparator 10 is composed of an operational amplifier and inputs a detection voltage corresponding to the current flowing from the current detection resistor 5 to the solenoid 1 to the other input terminal. When the other input is smaller than the one input, the power transistor 2 is activated. In order to turn on, and to turn off the power transistor 2 when the other input becomes larger than the one input, a voltage pulse corresponding to the magnitude relationship between the two inputs is output to the base of the power transistor 2 and the current of the solenoid 1 becomes the command voltage. The power transistor 2 is adapted to be turned on and off so as to comply. Reference numeral 11 is an adjuster for adjusting the operating point of the comparator 10.

The power supply circuit 4 will be described. Reference numerals 12 and 13 are commercial AC input terminals, and 14 is a switching power supply circuit. To the output terminals 42 and 43 of the switching power supply circuit 14, a smoothing capacitor 15 for voltage stabilization is connected and an output terminal 16 for outputting a DC voltage is provided, and further three terminal regulators 17 and 18 and a smoothing capacitor 19 are provided. , 20 and stabilizing circuits 23, 24 for outputting different DC voltages from output terminals 21, 22 are sequentially connected. The output terminal 16 is connected to the terminal 25 for the solenoid 1 and the terminal 26 of the comparator 10, and the output terminal 21 that obtains a voltage lower than that of the output terminal 16 is the terminal 27 of the oscillator 9 and the terminal 28 of the amplifier 8. The output terminal 22 connected to the terminal 30 of the regulator 11 and for obtaining a negative voltage is connected to the terminal 29 of the amplifier 8 and the terminal 31 of the regulator 11.

Here, as shown in FIG. 2, the switching power supply circuit 14 includes a first rectifying and smoothing device including a diode bridge 32 for full-wave rectifying commercial AC from the input terminals 12 and 13 and a smoothing capacitor 33. A transformer 37 having a circuit 34 and having a primary coil 36 connected to the first rectifying / smoothing circuit 34 via a switching element 35 such as a transistor is provided. 37A is an iron core of the transformer 37. A secondary rectifying / smoothing circuit 41 having a rectifying diode 39 and a smoothing capacitor 40 is connected to the secondary coil 38 of the transformer 37. The induced voltage is converted into a direct current and output to the output terminals 42 and 43. The secondary coil 38 has a smaller number of turns than the primary coil 36 so as to reduce the voltage of the primary coil 36. Reference numeral 44 is a control circuit for turning on and off the switching element 35. The control circuit 44 compares the voltage output from the second rectifying / smoothing circuit 41 with the reference voltage E and outputs a voltage corresponding to the difference, the triangular wave voltage from the oscillator 46, and the error amplifier 45. Of the pulse width modulator 47, which compares the output voltage of the pulse width modulator 47 with the output voltage of the error amplifier 45 and outputs a pulse voltage of a constant cycle having a pulse width corresponding to the output voltage of the error amplifier 45. It has a drive circuit 48 which is turned on and off, so that when the output voltage of the second rectification smoothing circuit 41 in the secondary coil 38 becomes larger than the reference voltage E, the on time of the switching element 35 is turned on and off. The output voltage is made constant by shortening it and making it longer when the output voltage becomes smaller than the reference voltage E.

Next, the operation of this embodiment will be described. The commercial alternating current applied to the input terminals 12 and 13 of the power supply circuit 4 is rectified by the switching power supply circuit 14 by the diode bridge 32 of the first rectifying and smoothing circuit 34, smoothed by the capacitor 33, and converted into direct current. Is applied to the primary coil 36 of the transformer 37 after being made alternating by the switching element 35 which is repeatedly turned on and off by the control circuit 44. Therefore, the secondary coil 38 has a turn ratio of both coils 36, 38. Based on this, an alternating voltage that is stepped down is induced, and this induced voltage is rectified by the diode 39 of the second rectifying and smoothing circuit 41, smoothed by the capacitor 40, converted to direct current, and output. The ON time of the switching element 35 is controlled by the control circuit 44 so that the ON time of the switching element 35 is short when the output voltage is higher than the reference voltage E, and the ON time of the switching element 35 is longer when the output voltage is lower than the reference voltage E. Since the voltage is made constant, when the induced voltage to the secondary coil 38 is increased by using a commercial AC with a high voltage, the ON time of the switching element 35 is shortened, and a commercial AC with a low voltage is used. When the induced voltage to the secondary coil 38 becomes low by using it, the ON time of the switching element 35 is lengthened and the output of the second rectifying / smoothing circuit 41 that averages the induced voltage of the secondary coil 38. The output voltage becomes constant regardless of the commercial AC voltage.

The output voltage of the switching power supply circuit 14 is further stabilized by the smoothing capacitor 15, and is further converted and stabilized to a required voltage by the stabilization circuits 23 and 24 which are sequentially connected, and the output terminal 16 , 21 and 22 are connected to the terminal 25 for the solenoid 1 and the terminals 26, 27, 28, 29, 30, 31 of the drive control circuit 3 to operate the solenoid 1 and the drive control circuit 3. DC power is supplied. Since the output voltage of the switching power supply circuit 14 does not change even if commercial alternating currents having different voltages are input as described above, it is possible to use different alternating voltage commercial alternating currents in the common power supply circuit 4.

The switching power supply circuit 14 may be configured as shown in FIG. In FIG. 3, the same parts as those in FIG. 2 are designated by the same reference numerals, and different points will be described. The transformer 37 further has a tertiary coil 49, and the control circuit 44 supplies a voltage induced in the tertiary coil 49 when the primary coil 36 is conducting via a resistor 50 and a capacitor 51 so as to turn on the transistor 35 serving as a switching element. A blocking oscillation circuit is configured by positive feedback, and a starting circuit 53 having a resistor 52 is provided. Then, the winding direction of the secondary coil 38 is selected so that the voltage induced when the conduction of the primary coil 36 is stopped by turning off the transistor 35 is in the forward direction of the diode 39. In the tertiary coil 49, a series circuit of a diode 54 and a capacitor 55 in which the voltage induced in the tertiary coil 49 by the conduction of the secondary coil 38 when the conduction of the primary coil 36 is stopped is in the forward direction. Are connected in parallel, and further, the current introduced from the tertiary coil 49 to turn on the transistor 35 when the primary coil 36 is conducting is bypassed between the diode 54 and the capacitor 55 so that the on time of the switching element 35 can be adjusted. , A Zener diode 56 is provided. Numeral 57 is a diode for preventing a large negative voltage from being applied to the base of the transistor 35.

In the operation of the switching power supply circuit of FIG. 3, when commercial AC is applied to the input terminals 12 and 13, the transistor 35 starts to turn on by the current from the starting circuit 53, whereby the primary coil 36 starts to conduct and the tertiary coil 36 starts to conduct. A voltage is induced in the coil 49, a current is received from the tertiary coil 49 to the base, and the transistor 35 instantly turns on. Then, the current in the primary coil 36 increases, but eventually the resistance of the transistor 35 stops increasing the current. Along with this, the voltage induced in the tertiary coil 49 decreases, and when the base current of the transistor 35 decreases, the current in the primary coil 36 further decreases. This lowers the induced voltage in the tertiary coil 49, so that the transistor 35 is instantaneously operated. Turn off. Then, the on / off operation of the transistor 35 is periodically repeated. In the secondary coil 38, due to the rectifying action of the diode 39, the primary coil 36 does not conduct when it is conducting, and the voltage induced when the primary coil 36 stops conducting is charged in the capacitor 40 through the diode 39 and smoothed. It is converted and output. When the secondary coil 38 is conducting, a voltage proportional to the voltage induced in the secondary coil 38 and charged in the capacitor is induced in the tertiary coil 49 and charged in the capacitor 55, and when the primary coil 36 conducts, A negative voltage is applied to the anode of the Zener diode 56. Therefore, the larger the voltage output from the secondary coil 38 to the diode 39 and the capacitor 40, the more the base current of the transistor 35 is bypassed to the Zener diode 56, so that the on-time of the transistor 35 is increased. However, if the output voltage of the second rectifying / smoothing circuit 41 in the secondary coil 38 is increased, it is adjusted to be shorter, and if the output voltage is decreased, it is adjusted to be increased, so that the output voltage can be made constant. Since the output voltage can be made constant as described above, a constant output voltage can be obtained even when commercial alternating currents having different voltages are used, and the same effect as that of FIG. 2 can be obtained.

[0014]

As described above, according to the present invention, in the switching power supply circuit, the on time of the switching element that is turned on and off connected to the primary coil of the transformer is controlled by the control circuit to change from the secondary coil of the transformer. Since the output voltage that is output to the second rectifying and smoothing circuit is made constant, it is possible to change the power supply circuit by reducing the DC voltage to a constant DC voltage regardless of using a commercial AC of different voltage. Instead, commercial alternating current of different voltage can be used. Therefore, the control circuit for the same electromagnetic control valve can be shared, and waste of manufacturing and management can be eliminated.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing a partial block diagram of the switching power supply circuit in FIG.

FIG. 3 is an electric circuit diagram showing another example of the switching power supply circuit.

[Explanation of symbols]

 1 Solenoid 2 Power Transistor 3 Drive Control Circuit 4 Power Supply Circuit 14 Switching Power Supply Circuit 34 First Rectifying and Smoothing Circuit 35 Switching Element 36 Primary Coil 37 Transformer 38 Secondary Coil 41 Second Rectifying and Smoothing Circuit 44 Control Circuit

Claims (1)

[Claims for utility model registration] 1. A power transistor connected in series to a solenoid of an electromagnetic control valve, a drive control circuit for driving the power transistor, and a power source serving as a DC power source for the solenoid and the drive control circuit. A power supply circuit for step-down rectifying commercial alternating current, a transformer having a primary coil and a secondary coil, a switching element that is turned on and off in series with the primary coil of the transformer, and commercial alternating current. A first rectifying and smoothing circuit that rectifies and smoothes and applies it to the primary coil of the transformer via a switching element, and rectifies the induced voltage to the secondary coil that is connected to the secondary coil of the transformer.
A switching power supply circuit having a second rectifying and smoothing circuit for smoothing and outputting, and a control circuit for controlling the on-time of the switching element so as to make the output voltage from the second rectifying and smoothing circuit constant A control device for an electromagnetic control valve.