阅读说明：本技术 电发热件电源驱动电路及封口机电路 (Electric heating element power supply driving circuit and sealing machine circuit ) 是由 陶佳 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种电发热件电源驱动电路及封口机电路,其中该电发热件电源驱动电路包括输入单元、整流单元、低压开关控制单元以及功率转换单元；低压开关控制单元包括连接开关和与连接开关电性连接的控制装置,连接开关电性连接在整流单元和功率转换单元之间,控制装置用于根据低压控制信号实时控制连接开关的工作状态；功率转换单元包括高频变压器和自激振荡电路,高频变压器的初级绕组通过自激振荡电路与连接开关电性连接,高频变压器的次级绕组用于与电发热件电性连接；本发明封口机电路中采用上述电发热件电源驱动电路来驱动电发热件工作,可有效降低封口机电路整体的待机消耗功率,提高工作效率,节约电能。(The invention discloses an electric heating element power supply driving circuit and a sealing machine circuit, wherein the electric heating element power supply driving circuit comprises an input unit, a rectifying unit, a low-voltage switch control unit and a power conversion unit; the low-voltage switch control unit comprises a connecting switch and a control device electrically connected with the connecting switch, the connecting switch is electrically connected between the rectifying unit and the power conversion unit, and the control device is used for controlling the working state of the connecting switch in real time according to a low-voltage control signal; the power conversion unit comprises a high-frequency transformer and a self-oscillation circuit, a primary winding of the high-frequency transformer is electrically connected with the connecting switch through the self-oscillation circuit, and a secondary winding of the high-frequency transformer is electrically connected with the electric heating element; the electric heating element power supply driving circuit is adopted in the sealing machine circuit to drive the electric heating element to work, so that the whole standby power consumption of the sealing machine circuit can be effectively reduced, the working efficiency is improved, and the electric energy is saved.)

1. A power supply driving circuit of an electric heating element is characterized by comprising an input unit, a rectifying unit, a low-voltage switch control unit and a power conversion unit;

the input unit is used for receiving an external alternating current power supply signal;

the rectifying unit is electrically connected with the input unit and is used for processing the alternating current signal output by the input unit into a direct current signal;

the low-voltage switch control unit comprises a connecting switch and a control device electrically connected with the connecting switch, the connecting switch is electrically connected between the rectifying unit and the power conversion unit, and the control device is used for controlling the working state of the connecting switch in real time according to a low-voltage control signal;

the power conversion unit comprises a high-frequency transformer and a self-oscillation circuit, wherein a primary winding of the high-frequency transformer is electrically connected with the connecting switch through the self-oscillation circuit, and a secondary winding of the high-frequency transformer is electrically connected with the electric heating element.

2. An electric heating element power supply driving circuit according to claim 1, wherein the self-oscillation circuit comprises a first three-pole switching transistor and a second three-pole switching transistor electrically connected between the output end of the connecting switch and the ground, the first three-pole switching transistor and the second three-pole switching transistor are connected in series, a first capacitor and a second capacitor are further connected in parallel at two ends of the first three-pole switching transistor and the second three-pole switching transistor, the first capacitor and the second capacitor are connected in series, and a voltage center point is formed between the first capacitor and the second capacitor;

the primary winding comprises a center coil and a first secondary coil and a second secondary coil, one end of the center coil is electrically connected with the voltage center point, and the other end of the center coil is electrically connected between the first three-pole switching transistor and the second three-pole switching transistor;

one end of the first auxiliary coil is electrically connected with the control end of the first three-pole switching transistor and is used for providing a starting signal for the first three-pole switching transistor;

one end of the second secondary winding is electrically connected with the control end of the second three-pole switching transistor and is used for providing a starting signal for the second three-pole switching transistor;

the self-oscillation circuit further comprises a starting circuit, one end of the starting circuit is in telecommunication connection with the central coil, the other end of the starting circuit is in electric connection with the control end of the first three-pole switching transistor, and the starting circuit is used for turning on the first three-pole switching transistor when the power conversion unit is powered on.

3. An electric heating element power supply driving circuit according to claim 2, wherein the starting circuit comprises a charging resistor, a charging capacitor and a trigger diode; the charging resistor and the charging capacitor are connected in series at two ends of a power supply circuit of the first three-pole switch transistor, one end of the trigger diode is electrically connected with the positive end of the charging capacitor, and the other end of the trigger diode is electrically connected with the control end of the first three-pole switch transistor.

4. An electric heating element power supply driving circuit according to claim 2, wherein the first sub-coil is electrically connected to the control terminal of the first three-pole switching transistor through a first RC coupling circuit, and the second sub-coil is electrically connected to the control terminal of the second three-pole switching transistor through a second RC coupling circuit.

5. An electric heating element power supply driving circuit according to claim 2, wherein a discharge resistor is connected in parallel to each of two ends of the first capacitor and the second capacitor.

6. An electric heating element power supply driving circuit according to claim 1, wherein the control means comprises a relay and a switch circuit electrically connected to the relay, the switch circuit being configured to control the power supply to the relay.

7. The electric heating element power driving circuit according to claim 6, wherein the switching circuit comprises a third switching transistor electrically connected to the relay, and a control terminal of the third switching transistor is electrically connected to a controller capable of sending a low voltage control signal.

8. A sealing machine circuit comprising an electric heating member for sealing and the electric heating member power supply driving circuit according to any one of claims 1 to 7.

9. The capper circuit of claim 8, further comprising a controller and an auxiliary power circuit electrically connected to an output of the rectifier unit, the auxiliary power circuit being configured to provide power to the controller, the controller being electrically connected to the control device.

10. The capper circuit of claim 9, wherein a temperature sensor is disposed adjacent to said electric heating element and electrically connected to said controller, said controller is further electrically connected to said control device, and said controller controls the operation of said connection switch according to the feedback from said temperature sensor.

Technical Field

The invention relates to the technical field of power supply driving, in particular to a power supply driving circuit of an electric heating element and a sealing machine circuit.

Background

The sealing machine is an electric device for sealing a plastic bag filled with articles by utilizing an electric heating principle, mainly comprises an electric heating piece and a power supply driving circuit, and the electric heating piece is driven by the power supply driving circuit to generate heat, so that the plastic bag is subjected to thermoplastic sealing. The power driving circuit of the sealing machine used at present mostly adopts an old-fashioned power frequency transformer or a conventional switch power circuit to form a driving power supply, the driving power supply starts from the power-on, a primary coil of the transformer is always connected in an alternating current commercial power loop and consumes electric energy all the time, so the standby power is large, the energy conservation is not facilitated, the power factor is low, the power loss is serious, the extra load of the power transformer can be increased, and the interference to a power grid is large.

Disclosure of Invention

The present invention aims to solve the above technical problems and provide a power driving circuit for an electric heating element and a sealing machine circuit with low standby power consumption and high working efficiency.

In order to achieve the purpose, the invention discloses a power supply driving circuit of an electric heating element, which is characterized by comprising an input unit, a rectifying unit, a low-voltage switch control unit and a power conversion unit;

the input unit is used for receiving an external alternating current power supply signal;

the rectifying unit is electrically connected with the input unit and is used for processing the alternating current signal output by the input unit into a direct current signal;

the low-voltage switch control unit comprises a connecting switch and a control device electrically connected with the connecting switch, the connecting switch is electrically connected between the rectifying unit and the power conversion unit, and the control device is used for controlling the working state of the connecting switch in real time according to a low-voltage control signal;

the power conversion unit comprises a high-frequency transformer and a self-oscillation circuit, wherein a primary winding of the high-frequency transformer is electrically connected with the connecting switch through the self-oscillation circuit, and a secondary winding of the high-frequency transformer is electrically connected with the electric heating element.

Preferably, the self-oscillation circuit includes a first three-pole switching transistor and a second three-pole switching transistor electrically connected between the output end of the connection switch and the ground, the first three-pole switching transistor and the second three-pole switching transistor are connected in series, two ends of the first three-pole switching transistor and the second three-pole switching transistor are further connected in parallel with a first capacitor and a second capacitor, the first capacitor and the second capacitor are connected in series, and a voltage center point is formed between the first capacitor and the second capacitor;

the primary winding comprises a center coil and a first secondary coil and a second secondary coil, one end of the center coil is electrically connected with the voltage center point, and the other end of the center coil is electrically connected between the first three-pole switching transistor and the second three-pole switching transistor;

one end of the first auxiliary coil is electrically connected with the control end of the first three-pole switching transistor and is used for providing a starting signal for the first three-pole switching transistor;

one end of the second secondary winding is electrically connected with the control end of the second three-pole switching transistor and is used for providing a starting signal for the second three-pole switching transistor;

the self-oscillation circuit further comprises a starting circuit, one end of the starting circuit is in telecommunication connection with the central coil, the other end of the starting circuit is in electric connection with the control end of the first three-pole switching transistor, and the starting circuit is used for turning on the first three-pole switching transistor when the power conversion unit is powered on.

Preferably, the starting circuit comprises a charging resistor, a charging capacitor and a trigger diode; the charging resistor and the charging capacitor are connected in series at two ends of a power supply circuit of the first three-pole switch transistor, one end of the trigger diode is electrically connected with the positive end of the charging capacitor, and the other end of the trigger diode is electrically connected with the control end of the first three-pole switch transistor.

Preferably, the first secondary winding is electrically connected to the control terminal of the first three-pole switching transistor through a first RC coupling circuit, and the second secondary winding is electrically connected to the control terminal of the second three-pole switching transistor through a second RC coupling circuit.

Preferably, two ends of the first capacitor and the second capacitor are respectively connected in parallel with a discharge resistor.

Preferably, the control device includes a relay and a switch circuit electrically connected to the relay, and the switch circuit is configured to control power supply to the relay.

Preferably, the switch circuit includes a third switching transistor electrically connected to the relay, and a control end of the third switching transistor is electrically connected to a controller capable of sending out a low-voltage control signal.

The invention also discloses a sealing machine circuit which comprises an electric heating element for sealing and the electric heating element power supply driving circuit.

Preferably, the power supply device further comprises a controller and an auxiliary power supply circuit electrically connected with the output end of the rectifying unit, wherein the auxiliary power supply circuit is used for supplying power to the controller, and the controller is electrically connected with the control device.

Preferably, a temperature sensor electrically connected with the controller is further arranged near the electric heating element, the controller is further electrically connected with the control device, and the controller can control the working state of the connecting switch according to the feedback of the temperature sensor.

Compared with the prior art, the electric heating element power supply driving circuit is adopted in the sealing machine circuit to drive the electric heating element to work, the power supply driving circuit comprises a low-voltage switch control unit and a power conversion unit, wherein the low-voltage switch control unit comprises a connecting switch and a control device electrically connected with the connecting switch, and the power conversion unit is arranged at the rear end of the connecting switch, so that when the sealing machine is required to be in a standby state, the control device disconnects the connecting switch under the action of a low-voltage control signal, thereby the power conversion unit is disconnected with the high-voltage circuit part, the high-frequency transformer and the self-oscillation circuit do not consume electric energy any more, the standby power consumed by the rectification unit and the low-voltage switch control unit positioned at the front end is extremely low, so that the whole standby power consumption of the sealing machine circuit can be effectively reduced, and the working efficiency is improved; in addition, the power conversion unit comprises a high-frequency transformer and a self-oscillation circuit, wherein the self-oscillation circuit excites direct current oscillation change on one side of a primary winding of the high-frequency transformer, so that an electric signal is induced on one side of a secondary winding of the high-frequency transformer to supply power to the electric heating element, the conversion efficiency of the power conversion unit is higher, and electric energy is further saved.

Drawings

Fig. 1 is a schematic structural diagram of a sealing machine circuit in an embodiment of the present invention.

Fig. 2 is a detailed circuit diagram of the sealing machine circuit in fig. 1.

Detailed Description

In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.

As shown in fig. 1, the embodiment discloses a sealing machine circuit for the specific operation of the sealing machine, which includes an electric heating element RHT for sealing and a power driving circuit for driving the electric heating element RHT to operate. The power supply driving circuit includes an input unit 10, a rectifying unit 11, a low-voltage switch control unit 12, and a power conversion unit 13.

The input unit 10 includes an input port for receiving an external ac power signal, i.e. external ac mains power, to enter the power driving circuit via the input port.

The rectifying unit 11 is electrically connected to the input unit 10, and is configured to process the ac signal output by the input unit 10 into a dc signal, and the rectifying unit 11 in this embodiment is preferably a bridge rectifier circuit.

The low-voltage switch control unit 12 comprises a connecting switch J0 and a control device 120 electrically connected with the connecting switch J0, the connecting switch J0 is electrically connected between the rectifying unit 11 and the power conversion unit 13, and the control device 120 is used for controlling the working state of the connecting switch J0 in real time according to a low-voltage control signal.

The power conversion unit 13 comprises a high-frequency transformer T and a self-oscillation circuit 130, wherein a primary winding N0 of the high-frequency transformer T is electrically connected with a connecting switch J0 through the self-oscillation circuit 130, and a secondary winding N4 of the high-frequency transformer T is used for being electrically connected with an electric heating element RHT. Under the action of the self-oscillation circuit 130, the power supply signal on the primary winding N0 side of the high-frequency transformer T oscillates and changes, so that the working power supply is induced on the secondary winding N4 side.

With the driving power supply in the above embodiment, the commercial ac signal enters the rectifying unit 11 via the input unit 10, and the rectifying unit 11 rectifies the ac power, outputs the dc power, and supplies the dc power to the power converting unit 13 at the rear end through the connection switch J0. When the electric heating element RHT is required to suspend operation, the operating state of the control device 120 is changed by a low-voltage control signal, so that the operating state of the connecting switch J0 is changed by the control device 120, that is, the connecting switch J0 is changed from on to off, and then the high-voltage power supply of the power conversion unit 13 is disconnected, so that the power conversion unit 13 is completely in the power-off state, the power conversion unit 13 is prevented from consuming higher standby power, and the operating efficiency of the driving power supply is improved. In addition, the self-oscillation circuit 130 in the power conversion unit 13 excites the direct current oscillation change at the side of the primary winding N0 of the high-frequency transformer T, so that an electric signal is induced at the side of the secondary winding N4 of the high-frequency transformer T to supply power to the electric heating element RHT, thereby the conversion efficiency of the power conversion unit 13 is relatively high, and the electric energy is further saved.

Further, as shown in fig. 2, the self-oscillation circuit 130 includes a first three-pole switching transistor Q1 and a second three-pole switching transistor Q2 electrically connected between the output end of the connection switch J0 and the ground, the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 are connected in series, a first capacitor C1 and a second capacitor C2 are further connected in parallel between the two ends of the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2, the first capacitor C1 and the second capacitor C2 are connected in series, and a voltage center point U0 is formed between the first capacitor C1 and the second capacitor C2.

The primary winding N0 includes a center coil N1 and a first sub-coil N2 and a second sub-coil N3, one end of the center coil N1 is electrically connected to the voltage center point U0, and the other end of the center coil N1 is electrically connected between the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2, that is, the other end of the center coil N1 is located on a connection line between the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2.

One end of the first sub-coil N2 is electrically connected to the control terminal of the first three-pole switching transistor Q1 for providing an activation signal to the first three-pole switching transistor Q1.

One end of the second sub-coil N3 is electrically connected to the control terminal of the second three-pole switching transistor Q2 for supplying an activation signal to the second three-pole switching transistor Q2.

The self-oscillation circuit 130 further includes a start-up circuit 131, one end of the start-up circuit 131 is electrically connected to the center coil N1, the other end of the start-up circuit 131 is electrically connected to the control terminal of the first three-pole switching transistor Q1, and the start-up circuit 131 is configured to turn on the first three-pole switching transistor Q1 when the power conversion unit 13 is powered on.

The operation principle of the self-oscillation circuit 130 in the above embodiment is as follows: when the connection switch J0 is connected by a low-voltage control signal, a dc power signal flows into the first capacitor C1 and the second capacitor C2 through the connection switch J0, the first capacitor C1 is charged first, the power signal is filtered by the first capacitor C1 and the second capacitor C2 which are connected in series, and after the first capacitor C1 is charged, a voltage center point U0 is formed between the first capacitor C1 and the second capacitor C2. The electrical signal from the voltage center point U0 enters the start circuit 131 through the center coil N1, and the start circuit 131 generates a start signal at the control terminal of the first three-pole switching transistor Q1, and the first three-pole switching transistor Q1 is activated by the start signal, so that the first three-pole switching transistor Q1 is turned on first. When the first three-pole switching transistor Q1 is turned on, the first capacitor C1 discharges through the center coil N1 and the first three-pole switching transistor Q1, and charges the second capacitor C2. When the first capacitor C1 stops discharging, the first three-pole switch transistor Q1 is turned off, the electric signal on the center coil N1 disappears, and simultaneously the second sub-coil N3 generates an induced voltage, when the induced voltage reaches the gate-level conduction voltage threshold of the second three-pole switch transistor Q2, the second three-pole switch transistor Q2 is turned on, and then the second capacitor C2 discharges through the second three-pole switch transistor Q2, the center coil N1 and the first capacitor C1, and charges the first capacitor C1, so that the center coil N1 generates the electric signal again. After the second capacitor C2 finishes discharging, the second three-pole switch transistor Q2 is turned off, the electric signals on the center coil N1 and the first secondary coil N2 all disappear, meanwhile, the first secondary coil N2 generates induced voltage, when the induced voltage reaches the gate-level conduction voltage threshold of the first three-pole switch transistor Q1, the first three-pole switch transistor Q1 is turned on again, so that the first capacitor C1 discharges again through the center coil N1 and the first three-pole switch transistor Q1, and the center coil N1 generates the electric signal again. With this, the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 are alternately turned on, so that the center coil N1 of the high-frequency transformer T generates self-oscillation, and an electric signal is induced in the secondary winding N4 of the high-frequency transformer T, and the electric heating element RHT generates heat according to the power signal, thereby realizing the sealing function.

Specifically, referring to fig. 2 again, the starting circuit 131 includes a charging resistor R1, a charging capacitor C3 and a trigger diode D1. The charging resistor R1 and the charging capacitor C3 are connected in series at two ends of a power supply circuit of the first three-pole switching transistor Q1, one end of the trigger diode D1 is electrically connected with the positive electrode end of the charging capacitor C3, and the other end of the trigger diode D1 is electrically connected with the control end of the first three-pole switching transistor Q1. When the connection switch J0 is closed to power on, the electric signal generated by the voltage center point U0 is loaded onto the charging resistor R1 through the center coil N1, and then the charging capacitor C3 is charged through the charging resistor R1, when the voltage at the two ends of the charging capacitor C3 reaches the conduction voltage of the trigger diode D1, the trigger diode D1 is turned on, so that the control end of the first three-pole switch transistor Q1 reaches the conduction voltage threshold, and the first three-pole switch transistor Q1 is started. The trigger diode D1 in this embodiment is triggered bidirectionally, and is convenient to install and use.

Further, the first sub-winding N2 is electrically connected to the control terminal of the first three-pole switching transistor Q1 through a first RC coupling circuit, and the second sub-winding N3 is electrically connected to the control terminal of the second three-pole switching transistor Q2 through a second RC coupling circuit. Specifically, the first RC coupling circuit includes a first coupling capacitor C4 and a first coupling resistor R2 connected in series, and the second RC coupling circuit includes a second coupling capacitor C5 and a second coupling resistor R3 connected in series. The induced voltage generated at the first sub-coil N2 is applied to the control terminal of the first three-pole switching transistor Q1 through the first coupling circuit, and the induced voltage generated at the second sub-coil N3 is applied to the control terminal of the second three-pole switching transistor Q2 through the second coupling circuit, so that the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 obtain stable and effective driving signals. Preferably, the control terminal of the first three-pole switching transistor Q1 is further provided with a first zener diode D2 and a first zener resistor R7, and the control terminal of the second three-pole switching transistor Q2 is further provided with a second zener diode D3 and a second zener resistor R8, so that the on-state voltage signals of the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 during the on-state period are more stable.

Furthermore, in order to enable the first capacitor C1 and the second capacitor C2 to be more thoroughly discharged, two ends of the first capacitor C1 and the second capacitor C2 are respectively connected in parallel with a discharging resistor R4 and a discharging resistor R5, so that the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 are stably switched according to a set frequency, and the self-oscillation effect of the center coil N1 is effectively guaranteed.

More specifically, the first three-pole switching transistor Q1 and the second three-pole switching transistor Q2 in the above-described embodiments are preferably field effect transistors.

In another preferred embodiment of the sealing machine circuit of the present invention, as shown in fig. 1 and fig. 2, the sealing machine circuit further includes a controller 2 and an auxiliary power circuit 14 electrically connected to the output terminal of the rectifying unit 11, the auxiliary power circuit 14 is used for providing power to the controller 2, and the controller 2 is electrically connected to the control device 120 to send a corresponding control signal to the control device 120.

Further, the control device 120 includes a relay RY and a switch circuit electrically connected to the relay RY, and the switch circuit is used for controlling the power supply of the relay. Further, the switch circuit includes a third switch transistor Q3 electrically connected to the relay RY, and a control terminal of the third switch transistor Q3 is electrically connected to the controller 2. In this embodiment, the third switching transistor Q3 is preferably a transistor, and the controller 2 controls the on/off of the transistor by controlling the gate voltage level of the transistor control terminal Q3 to control the power supply of the relay RY, and further controls the on/off of the connection switch J0 through the relay RY.

Furthermore, in order to avoid potential safety hazards caused by sparks (electric arcs) generated when the connecting switch J0 is pulled in, two ends of the connecting switch J0 are also connected in parallel with a high-frequency spark absorbing circuit. Specifically, the high-frequency spark absorbing circuit comprises a safety resistor R6 and a safety capacitor C6 which are connected in series, and a thermistor NTC 1. In this embodiment, the safety resistor R6, the safety capacitor C6 and the thermistor NTC1 form a conditional charge-discharge network. When the connection switch J0 is attracted to generate arc spark, the temperature rises, so that the thermistor NTC1 is turned on, and thus high-frequency arc enters a charging and discharging network where the thermistor NTC1 is located, arc energy is eliminated through a charging and discharging effect between the safety resistor R6 and the safety capacitor C6, when the arc spark disappears, the thermistor NTC1 disconnects a charging network, and because direct current flows into the connection switch J0, an electric signal cannot bypass the connection switch J0 and enters the power conversion unit 13 at the rear end through the charging resistor R1 and the charging capacitor C3.

Further, a temperature sensor NTC0 electrically connected to the controller 2 is disposed near the electric heating element RHT, the controller 2 is also electrically connected to the control device 120, and the controller 2 can control the operating state of the connection switch J0 according to the feedback of the temperature sensor NTC 0. In this embodiment, the controller 2 can be connected or disconnected with the connection switch J0 according to the real-time temperature of the electric heating element RHT, so that the heating time of the electric heating element RHT is controlled, the electric energy is saved in the operation of the sealing machine, and the operation is convenient.

In addition, as shown in fig. 2, in order to further improve the safety performance of the power driving circuit, a mechanical main start switch SW and a safety element F1 are further disposed in the input unit 10, the main start switch SW controls the supply of the commercial power, and the safety element F1 protects components in the power driving circuit from being burned by the short-circuit current.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, therefore, the present invention is not limited by the appended claims.