CN211183393U - A control circuit for a single-phase AC motor - Google Patents

Abstract

The utility model discloses an adjustable single phase alternating current motor rotational speed and can carry out the single phase alternating current motor's of all-round protection control circuit to single phase alternating current motor, include: working power supply, bidirectional thyristor, trigger circuit, chronogenesis synchronous circuit and cross undervoltage sampling circuit, overheated sampling circuit and overcurrent sampling circuit for controlling bidirectional thyristor, this trigger circuit includes: the two output pins of the photoelectric isolation circuit for triggering are respectively connected with the two main electrodes of the bidirectional controllable silicon in a one-to-one correspondence way through output side current limiting resistors, and the gate pole of the bidirectional controllable silicon is connected with the corresponding output pin of the photoelectric isolation circuit for triggering; the output pin of the pulse width modulation circuit is connected with the control end of the photoelectric isolation circuit for triggering, and an anti-interference circuit is arranged between the power pin of the photoelectric isolation circuit for triggering and the working power supply. But control circuit wide application in various single phase alternating current motor.

Description

A control circuit for a single-phase AC motor

technical field

The utility model relates to a control circuit of an alternating current motor, in particular to a control circuit of a single-phase alternating current motor.

Background technique

At present, the AC motor in the traditional hand-held threading machine adopts a fixed speed, that is, its speed cannot be adjusted. Therefore, its control circuit is relatively simple, and usually only a fuse (fuser) is connected in series in the power supply circuit of the AC motor. In the actual use process, on the one hand, the starting current is large, which makes the temperature rise of the AC motor larger and shortens the service life of the AC motor; There is a serious safety hazard for the surrounding related personnel; in addition, the control circuit can only protect the over-current of the AC motor, but cannot sense the over-voltage, under-voltage and overheating of the AC motor, so it cannot conduct all-round monitoring of the AC motor. protection, shortening the service life of the AC motor.

Utility model content

The technical problem to be solved by the utility model is to provide a control circuit of the single-phase AC motor which can adjust the rotation speed of the single-phase AC motor and can protect the single-phase AC motor in all directions.

In order to solve the above-mentioned technical problems, the technical scheme adopted by the present invention is: a control circuit of a single-phase AC motor, the structure of which includes: a working power supply, a bidirectional thyristor, a trigger circuit for controlling the bidirectional thyristor, a The timing synchronization circuit of the synchronous trigger circuit, as well as the over-under-voltage sampling circuit, the over-temperature sampling circuit and the over-current sampling circuit, the specific structure of the trigger circuit includes: a pulse width modulation circuit and an optoelectronic isolation circuit for triggering, and an optoelectronic isolation circuit for triggering. The two output pins are respectively connected with the two main electrodes of the triac through the output side current limiting resistor, and the gate of the triac is connected with the corresponding output pin of the photoelectric isolation circuit for triggering; The output pin of the wide modulation circuit is connected to the control terminal of the photoelectric isolation circuit for triggering, and an anti-interference circuit is arranged between the power supply pin of the photoelectric isolation circuit for triggering and the working power supply. The anti-interference circuit includes: PNP type secondary transistor, NPN type one-stage transistor, diode, input side current limiting resistor and a pair of voltage divider resistors, the pair of voltage divider resistors includes: power side voltage divider resistor and ground side voltage divider resistor, the resistance value of the power side voltage divider resistor is greater than that of the ground side Twice the voltage divider resistor, one end of the power supply side voltage divider resistor is connected to one end of the ground side voltage divider resistor, and then connected to the positive electrode of the diode, and the other end of the power supply side voltage divider resistor is connected to the positive electrode of the working power supply, so The other end of the grounding side voltage divider resistor is connected to the negative electrode of the working power supply, the negative electrode of the diode is connected to the base electrode of the primary triode, and the collector of the primary triode is connected to the base electrode of the secondary triode through the input side current limiting resistor. connected, the emitter of the first-level triode is connected with the negative pole of the working power supply, the emitter of the second-level transistor is connected with the positive pole of the working power supply, and the collector of the second-level transistor is connected with the power supply pin of the photoelectric isolation circuit for triggering; The specific structure of the undervoltage sampling circuit includes: transformer, half-wave rectifier diode, charging capacitor, overvoltage and undervoltage output resistor, pull-down resistor, overvoltage and undervoltage output filter capacitor, power supply side diode, ground side diode and upper and lower limit dividers. piezoresistor, the primary coil of the transformer is connected to alternating current, the phase line with the same name of the secondary coil of the transformer is connected to the positive electrode of the half-wave rectifier diode, and the negative electrode of the half-wave rectifier diode is connected to one end of the upper limit voltage divider resistor Connected, the other end of the upper limit voltage divider resistor is connected with one end of the lower limit voltage divider resistor and the corresponding end of the charging capacitor, the other end of the charging capacitor and the other end of the lower limit voltage divider resistor are grounded, and the upper and lower limit dividers The connected end of the voltage resistor is used as the overvoltage and undervoltage output end, and one end of the pull-down resistor, the corresponding end of the filter capacitor of the overvoltage and undervoltage output end, the positive electrode of the power supply side diode, and the negative electrode of the ground side diode are connected to the said overvoltage output end, The other end of the pull-down resistor, the other end of the filter capacitor at the output end of the overvoltage and undervoltage, the cathode of the diode on the power supply side, and the anode of the diode on the grounding side are grounded.

As a preferred solution, in the control circuit of the single-phase AC motor, the timing synchronization circuit includes: an optoelectronic isolation circuit for synchronization, and two input ends of the optoelectronic isolation circuit for synchronization are connected in series through an AC current limiting resistor. In the AC power circuit, the power supply pin on the receiving side of the optoelectronic isolation circuit is connected to the working power supply through a pull-up resistor, and the output pin on the receiving side of the optoelectronic isolation circuit is connected in series with a resistor to form the output terminal to output a synchronous timing signal.

As a preferred solution, in the control circuit of the single-phase AC motor, the timing synchronization circuit further includes: a power-side diode and a ground-side diode, the anode of the power-side diode and the cathode of the ground-side diode. It is connected to the output end of the receiving side of the photoelectric isolation circuit, the cathode of the diode on the power supply side is connected with the anode of the working power supply, and the anode of the diode on the grounding side is connected with the cathode of the working power supply.

As a preferred solution, in the control circuit of the single-phase AC motor, a resistance-capacitance absorption circuit is arranged between the two main electrodes of the triac, and the resistance-capacitance absorption circuit includes a series-connected snubber resistor and snubber capacitor.

As a preferred solution, in the control circuit of the single-phase AC motor, an anti-interference filter capacitor is provided between one end of the pair of voltage dividing resistors connected to the anode of the diode and the cathode of the working power supply.

As a preferred solution, in the control circuit of the single-phase AC motor, the specific structure of the overcurrent sampling circuit includes: a current transformer, and a ninth filter capacitor is connected in parallel between two output ends of the current transformer , the nineteenth resistor, and the corresponding end of the current transformer is provided with a capacitor to ground, and an overcurrent output resistor is connected in series as an overcurrent output terminal, and the other end of the current transformer is grounded.

As a preferred solution, in the control circuit of the single-phase AC motor, the control circuit further includes a ninth transient diode, and the negative electrode of the ninth transient diode is connected to the corresponding end of the current transformer, and the ninth transient diode is connected to the corresponding end of the current transformer. The anodes of the nine transient diodes are grounded.

As a preferred solution, in the control circuit of the single-phase AC motor, the specific structure of the overheat sampling circuit includes: a temperature sensor, a corresponding end of the temperature sensor is used as an overheat output end, and the other end is grounded, and the overheating The output end is provided with a twenty-first resistor and an eleventh filter capacitor to the ground.

As a preferred solution, in the control circuit of the single-phase AC motor, the control circuit further includes a tenth transient diode, and the cathode of the tenth transient diode is connected to the overheating output end, and the tenth transient diode is connected to the overheating output terminal. The anodes of ten transient diodes are grounded.

As a preferred solution, in the control circuit of the single-phase AC motor, both ends of the charging capacitor are also connected in parallel with a charging filter capacitor.

The beneficial effects of the utility model are: the control circuit described in the utility model is simple and practical, with low cost, and can realize stepless speed regulation of the AC motor, avoid the situation of heating due to excessive current when the AC motor is started, and prolong the operation time. The service life of the AC motor, and because it can be started at a small speed, and then increase the speed according to the actual situation, the personal safety of the operator and the surrounding personnel is more reliably guaranteed; , Undervoltage sampling circuit, overheat sampling circuit and overcurrent sampling circuit, all-round protection for the AC motor, so that the AC motor will not be damaged due to sudden abnormality, and greatly prolong the service life of the AC motor. In addition, the over-voltage and under-voltage sampling circuits, the over-temperature sampling circuits and the over-current sampling circuits adopted in the present invention have simple and practical structures, which greatly reduces the cost and increases the market competitiveness.

Description of drawings

FIG. 1 is a schematic diagram of the electrical principle structure of the control circuit of the single-phase AC motor according to the present invention.

Detailed ways

The specific implementation of the control circuit of a single-phase AC motor according to the present utility model will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the control circuit of a single-phase AC motor according to the present utility model includes: a working power supply VCC5, a bidirectional thyristor Q3 with a model of BAT41, a trigger circuit for controlling the bidirectional thyristor Q3, A timing synchronization circuit for synchronizing trigger circuits, as well as an overvoltage and undervoltage sampling circuit, an overheating sampling circuit, and an overcurrent sampling circuit. The timing synchronization circuit includes: an optocoupler U2 as an optoelectronic isolation circuit for synchronization, and a power-side diode D7 and ground side diode D8, the two input pins of the optocoupler U2 are connected in series to the AC power circuit through the AC current limiting resistor, the resistors R11, R12 and R13 are connected in parallel to form the first parallel resistor group, and the resistors R14, R15 and R16 are connected in parallel , form a second parallel group, the first parallel group is connected in series with the second parallel group to form an AC current limiting resistor, the power supply pin of the receiving side of the optocoupler U2 is connected to the working power supply VCC5 through the pull-up resistor R17, and the output pin of the receiving side of the optocoupler U2 The series resistor R18 forms the output terminal to output the synchronous timing signal. The output terminal of the receiving side of the optocoupler U2 is connected to the anode of the power-side diode D7 and the cathode of the ground-side diode D8. The cathode of the power-side diode D7 is connected to the anode of the working power supply VCC5. The anode of the ground-side diode D8 is connected to the cathode of the working power supply VCC5; the specific structure of the trigger circuit includes: a pulse width modulation circuit (a common technology in the field, not shown in the figure, of course, it can also be simulated by microprocessing) , and an optocoupler U1 with a model of MOC3163 as a triggering optoelectronic isolation circuit, one output pin of optocoupler U1 is connected to a main electrode of the triac Q3 through an output-side current limiting resistor R4, and the other of optocoupler U1 One output pin is connected to the other main electrode of the triac Q3 through the output side current limiting resistor R5, and the other output pin of the optocoupler U1 is connected to the gate of the triac Q3; the pulse The output pin of the wide modulation circuit is connected with the control pin of the optocoupler U1. An anti-jamming circuit is arranged between the power pin of the optocoupler U1 and the working power supply VCC5. The anti-jamming circuit includes: PNP-type secondary transistor Q2, NPN-type The first-stage transistor Q1, the diode D1, the input side current limiting resistor R3 and a pair of voltage dividing resistors include: the power supply side voltage dividing resistor R1 and the grounding side voltage dividing resistor R2, the resistance of the power supply side voltage dividing resistor R1 The value is greater than twice the resistance value of the ground side voltage divider resistor R2, preferably the resistance value of the power side voltage divider resistor R1 is greater than three times the resistance value of the ground side voltage divider resistor R2 (here, a 36KΩ resistor is selected as the power side The resistance of the voltage dividing resistor R1 and 8KΩ is used as the grounding side voltage dividing resistor R2). One end of the power supply side voltage dividing resistor R1 is connected to one end of the grounding side voltage dividing resistor R2, and then connected to the anode of the diode D1. The power supply side The other end of the voltage dividing resistor R1 is connected to the positive electrode of the working power supply VCC5, the other end of the grounding side voltage dividing resistor R2 is connected to the negative electrode of the working power supply VCC, and the negative electrode of the diode D1 is connected to the base of the first-stage transistor Q1. The collector of transistor Q1 passes through the input The side current limiting resistor R3 is connected to the base of the secondary transistor Q2, the emitter of the primary transistor Q1 is connected to the negative pole of the working power supply VCC5 (commonly known as ground), and the emitter of the secondary transistor Q2 is connected to the working power supply VCC5 The positive pole is connected, The collector of the secondary transistor Q2 is connected to the power pin of the optocoupler U1. In this embodiment, a resistance-capacitance absorption circuit is provided between the two main electrodes of the triac Q3, and the resistance-capacitance absorption circuit includes: an absorption resistor R6 and an absorption capacitor C2 connected in series. An anti-interference filter capacitor C1 is provided between the end of the voltage dividing resistor R1 on the power supply side and the voltage dividing resistor R2 on the ground side connected to the positive electrode of the diode D1 and the negative electrode of the working power supply VCC5; the overvoltage and undervoltage sampling circuit includes: a transformer T1 ( Multiplexing with the power supply circuit), half-wave rectifier diode D3, charging capacitor C6, overvoltage and undervoltage output resistor R9, pull-down resistor R10, overvoltage and undervoltage output filter capacitor C8, power supply side diode D5, ground side diode D6, and upper limit The voltage dividing resistor R7 and the lower limit voltage dividing resistor R8, the two ends of the primary coil of the transformer T1 are respectively connected to the LIN and NIN of the alternating current, and the phase line (LIN) of the secondary coil of the transformer T1 has the same name as the half. The positive pole of the wave rectifier diode D3 is connected, the negative pole of the half-wave rectifier diode D3 is connected to one end of the upper limit voltage divider resistor R7, and the other end of the upper limit voltage divider resistor R7 is connected to one end of the lower limit voltage divider resistor R8 and the charging capacitor. The corresponding ends of C6 are connected, and the two ends of the charging capacitor C6 are also connected with a charging filter capacitor C7 in parallel. The terminal is used as an over- and under-voltage output terminal, and is connected to one end of the pull-down resistor R10, the corresponding terminal of the filter capacitor C8 of the over-under-voltage output terminal, and the anode of the power-side diode D5 and the cathode of the ground-side diode D6. The other end of the pull-down resistor R10 One end, the other end of the filter capacitor C8 at the output end of over-voltage and under-voltage, the negative electrode of the diode D5 on the power supply side, and the positive electrode of the diode D6 on the grounding side are grounded; the specific structure of the overcurrent sampling circuit includes: a current transformer (a common technology in the field , not shown in the figure) and a ninth transient diode D9, the two output ends of the current transformer are connected in parallel with a ninth The filter capacitor C9, the nineteenth resistor R19, the corresponding end of the current transformer is provided with a grounding capacitor C10, and an overcurrent output resistor R20 is connected in series as the overcurrent output end, the other end of the current transformer is grounded through the plug TEMP, The negative electrode of the ninth transient diode D9 is connected to the corresponding end of the current transformer, and the positive electrode of the ninth transient diode D9 is grounded; the specific structure of the overheat sampling circuit includes: a temperature sensor (a common technology in the art, Fig. (not shown in the figure), the tenth transient diode D10, the temperature sensor uses the plug TEMP and the corresponding socket (a common technology in the art, not shown in the figure) to use its corresponding end as an overheating output end, and connect the other end to ground , the overheating output end D10 is provided with a twenty-first resistor R21 and an eleventh filter capacitor C11 to the ground, the negative electrode of the tenth transient diode D10 is connected to the overheating output end, and the tenth transient diode D10 is connected to the Positive ground.

To sum up, it is only a preferred embodiment of the present utility model, and is not intended to limit the scope of the present utility model. and modifications should be included within the scope of the claims of the present invention.

Claims (10)

1. A control circuit for a single-phase ac motor, comprising: working power supply, bidirectional thyristor, be used for controlling bidirectional thyristor's trigger circuit, be used for synchronous trigger circuit's chronogenesis synchronous circuit and cross undervoltage sampling circuit, overheated sampling circuit and overflow sampling circuit, its characterized in that, trigger circuit's concrete structure includes: the two output pins of the photoelectric isolation circuit for triggering are respectively connected with two main electrodes of the bidirectional controllable silicon in a one-to-one correspondence way through output side current limiting resistors, and the gate pole of the bidirectional controllable silicon is connected with the corresponding output pin of the photoelectric isolation circuit for triggering; the output pin of pulse width modulation circuit links to each other with triggering photoelectric isolation circuit's control end, triggers to be provided with anti jamming circuit between photoelectric isolation circuit's power foot and the working power supply, and this anti jamming circuit includes: PNP type's second grade triode, NPN type's first grade triode, diode, input side current limiting resistor and a pair of divider resistance, this pair of divider resistance includes: the power supply side voltage-dividing resistor and the grounding side voltage-dividing resistor are connected, the resistance value of the power supply side voltage-dividing resistor is more than twice that of the grounding side voltage-dividing resistor, one end of the power supply side voltage-dividing resistor is connected with one end of the grounding side voltage-dividing resistor and then connected with the anode of the diode, the other end of the power supply side voltage-dividing resistor is connected with the anode of the working power supply, the other end of the grounding side voltage-dividing resistor is connected with the cathode of the working power supply, the cathode of the diode is connected with the base electrode of the first-stage triode, the collector electrode of the first-stage triode is connected with the base electrode of the second-stage triode through the input side current-limiting resistor, the emitter electrode of the first-stage triode is connected with the cathode of the working power supply, and the collector electrode of the second-; the specific structure of the over-voltage and under-voltage sampling circuit comprises: the transformer, a half-wave rectifier diode, a charging capacitor, an over-voltage and under-voltage output resistor, a pull-down resistor, a filter capacitor of an over-voltage and under-voltage output end, a power side diode, a grounding side diode, an upper limiting voltage divider resistor and a lower limiting voltage divider resistor, wherein alternating current is connected to a primary coil of the transformer, the same name end of a phase line of a secondary coil of the transformer is connected with the anode of the half-wave rectifier diode, the cathode of the half-wave rectifier diode is connected with one end of the upper limiting voltage divider resistor, the other end of the upper limiting voltage divider resistor is connected with one end of the lower limiting voltage divider resistor and the corresponding end of the charging capacitor, the other end of the charging capacitor and the other end of the lower limiting voltage divider resistor are grounded, the connected ends of the upper limiting voltage divider resistor and the lower limiting voltage divider resistor are used as over-voltage and under-voltage output ends, one end of the pull-down resistor, the, the other end of the pull-down resistor, the other end of the filter capacitor of the overvoltage and undervoltage output end, the cathode of the power supply side diode and the anode of the grounding side diode are grounded.

2. The control circuit of a single-phase ac motor according to claim 1, wherein said timing synchronization circuit comprises: the two input ends of the synchronous photoelectric isolation circuit are connected in series into an alternating current power supply loop through an alternating current limiting resistor, a power supply pin at the receiving side of the photoelectric isolation circuit is connected with a working power supply through a pull-up resistor, and an output pin at the receiving side of the photoelectric isolation circuit is connected with a resistor in series to form an output end to output a synchronous timing signal.

3. The control circuit of a single-phase ac motor according to claim 1, wherein said timing synchronization circuit further comprises: the photoelectric isolation circuit comprises a power supply side diode and a grounding side diode, wherein the anode of the power supply side diode and the cathode of the grounding side diode are connected with the output end of the receiving side of the photoelectric isolation circuit, the cathode of the power supply side diode is connected with the anode of a working power supply, and the anode of the grounding side diode is connected with the cathode of the working power supply.

4. The control circuit of a single-phase alternating-current motor according to claim 1, wherein a resistor-capacitor absorption circuit is provided between two main electrodes of the triac, and the resistor-capacitor absorption circuit includes an absorption resistor and an absorption capacitor connected in series.

5. The control circuit of a single-phase alternating current motor according to claim 1, wherein an anti-interference filter capacitor is provided between one end of the pair of voltage dividing resistors connected to the anode of the diode and the cathode of the operating power supply.

6. The control circuit of the single-phase alternating current motor according to any one of claims 1 to 5, wherein the overcurrent sampling circuit has a specific structure including: and a ninth filter capacitor and a nineteenth resistor are connected in parallel between the two output ends of the current transformer, a ground capacitor is arranged at the corresponding end of the current transformer, an overcurrent output resistor is connected in series to serve as an overcurrent output end, and the other end of the current transformer is grounded.

7. The control circuit of a single-phase alternating current motor according to claim 6, wherein the control circuit further comprises a ninth transient diode, a cathode of the ninth transient diode is connected to a corresponding end of the current transformer, and an anode of the ninth transient diode is grounded.

8. The control circuit of the single-phase alternating current motor according to any one of claims 1 to 5, wherein the specific structure of the overheat sampling circuit includes: and the corresponding end of the temperature sensor is used as an overheating output end, the other end of the temperature sensor is grounded, and the overheating output end is provided with a twenty-first resistor and an eleventh filter capacitor in a grounded mode.

9. The control circuit of a single-phase ac motor of claim 8, further comprising a tenth transient diode, wherein a cathode of the tenth transient diode is connected to said overheat output terminal, and an anode of the tenth transient diode is connected to ground.

10. The control circuit of a single-phase alternating current motor according to any one of claims 1 to 5, wherein a charge filter capacitor is further connected in parallel to both ends of the charge capacitor.

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