CN115740825A - Infrared welding device and driving method of infrared welding lamp tube - Google Patents

Abstract

The embodiment of the present invention discloses an infrared welding device and an infrared welding lamp driving method. The device is provided with a switching device to control the power conduction angle of the infrared welding lamp, and a controller is configured to control the switching device to preset Switching is performed at a first frequency within a time period, and switching is performed at a second frequency after a preset time period, wherein the first frequency is greater than the second frequency. Therefore, the starting current of the infrared welding lamp can be controlled within a small range at the initial start-up of the device, so that while ensuring the heating power of the infrared welding lamp, the cost can be reduced and the infrared welding lamp and switching devices can be effectively protected .

Description

Infrared Welding Device and Infrared Welding Lamp Driving Method

technical field

The invention relates to the technical field of electronic power, in particular to an infrared welding device and an infrared welding lamp driving method.

Background technique

With the increasing popularity of new clean energy, solar photovoltaic panels are becoming more and more popular, and users have higher and higher requirements for the power output of photovoltaic small panel cells. Since the voltage and power generated by each small photovoltaic cell are relatively small and cannot meet the practical application, it is necessary to realize the series-parallel connection of the cells by welding the cells to achieve higher power output.

Welding batteries generally use infrared welding lamps to irradiate and heat. In the prior art, the conduction angle is controlled by a thyristor to adjust the heating power of the infrared welding lamp tube. Although this method of controlling the heating power is simple, the reliability of the driver power device and the infrared welding lamp tube is not satisfactory. Since the impedance of the filament of the infrared welding lamp (such as iodine tungsten, quartz, carbon fiber, etc.) mostly has a strong positive temperature coefficient, taking a 1kw quartz infrared welding lamp as an example, when the filament temperature is 25°C, the impedance is only 4-5 Ohms, but the impedance can reach 40-50 ohms at a temperature of 1kW. When the infrared welding lamp is started, the instantaneous current is very large due to the low resistance of the filament. The instantaneous high current not only has a great impact on the life of the infrared welding lamp, but also requires a higher power level power device to drive the infrared welding lamp. This will inevitably result in larger volume and higher cost.

Contents of the invention

In view of this, an embodiment of the present invention provides an infrared welding device and an infrared welding lamp driving method to effectively protect the infrared welding lamp and the infrared welding lamp at a relatively low cost while ensuring the heating power of the infrared welding lamp. driver power devices.

In a first aspect, an infrared welding device is provided, the device comprising:

a rectification circuit configured to convert the input alternating current to direct current;

Infrared welding lamp;

a switching device connected in series with the infrared welding lamp at the output port of the rectifier circuit; and

The controller is configured to control the switching device to switch at a first frequency after starting, and control the switching device to switch at a second frequency after the infrared welding lamp tube is preheated;

Wherein, the first frequency is greater than the second frequency.

Optionally, the switching device is a metal oxide semiconductor transistor.

Optionally, the rectification circuit is a bridge rectification circuit.

Optionally, the device also includes:

An inductance element is connected in series with the switching device.

Optionally, the controller is configured to control the switching device to switch at a first frequency within a preset time period after power-on, and control the switching device to switch at a second frequency after the preset time period passes. switch.

Optionally, the controller is configured to control the conduction angle of each cycle of the switching tube device according to a power control signal after the preset time period elapses.

In a second aspect, an infrared welding lamp driving method is provided, the method comprising:

controlling the switching device to switch at a first frequency after startup;

controlling the switching device to switch at a second frequency after the infrared welding lamp tube is preheated;

Wherein, the first frequency is greater than the second frequency.

Optionally, controlling the switching device to switch at the first frequency after startup is specifically:

The switching device is controlled to switch at a first frequency within a preset time period after being powered on.

Optionally, the method also includes:

After the preset period of time, the conduction angle of each cycle of the switching tube device is controlled according to the power control signal.

In the present invention, a switch device is used to control the power conduction angle of the infrared welding lamp tube, and a controller is configured to control the switch device to switch at a first frequency within a preset time period after power-on. Switching is then performed at a second frequency, the first frequency being greater than the second frequency. Thus, the start-up current of the infrared welding lamp can be controlled within a small range at the initial start-up of the device, and the infrared welding lamp can be adjusted by controlling the conduction angle after the temperature of the infrared welding lamp rises to a certain value. power. Therefore, while ensuring the heating power of the infrared welding lamp tube, the cost is reduced and the infrared welding lamp tube and the driver power device are effectively protected.

Description of drawings

Through the following description of the embodiments of the present invention with reference to the accompanying drawings, the above and other objects, features and advantages of the present invention will be more clear, in the accompanying drawings:

Fig. 1 is a schematic circuit diagram of an infrared welding device of related art;

Fig. 2 is a schematic diagram of a simulated waveform after the start-up of an infrared welding device of the related art;

Fig. 3 is a schematic circuit diagram of an infrared welding device according to an embodiment of the present invention;

Fig. 4 is a schematic diagram of a simulation waveform after the infrared welding device of the embodiment of the present invention is started;

Fig. 5 is a schematic diagram of the unfolded simulation waveform after the infrared welding device of the embodiment of the present invention is started;

Fig. 6 is a schematic circuit diagram of another infrared welding device according to the embodiment of the present invention;

Fig. 7 is a flowchart of the driving of the infrared welding lamp according to the embodiment of the present invention.

Detailed ways

The present invention is described below based on examples, but the present invention is not limited to these examples. In the following detailed description of the invention, some specific details are set forth in detail. The present invention can be fully understood by those skilled in the art without the description of these detailed parts. In order not to obscure the essence of the present invention, well-known methods, procedures, procedures, components and circuits have not been described in detail.

Additionally, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.

Unless the context clearly requires, the words "including", "including" and similar words in the description should be interpreted as inclusive rather than exclusive or exhaustive; that is, "including but not limited to".

In the description of the present invention, it should be understood that the terms "first", "second" and so on are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of this manual, "starting" refers to starting when the infrared welding lamp is not preheated.

FIG. 1 is a schematic circuit diagram of an infrared welding device in the related art. As shown in Figure 1, the switching device S1 and the infrared welding lamp 12 are connected in series at the output port of the rectifier circuit 11, and the rectifying circuit 11 converts the input alternating current AC1 into a direct current, and the infrared welding lamp 12 is controlled by switching the switching device S1 The power conduction angle to adjust the heating power of the infrared welding lamp. Wherein, the rectification circuit 11 is a bridge rectification circuit including four diodes. In this infrared welding device, since the switching device used is usually IGBT or BJT (Bipolar Junction Trans i stor-BJT, bipolar junction transistor), the reliability of the infrared welding lamp and the switching device is poor, and the The life of the infrared welding lamp has a great influence, and at the same time, it is necessary to select a switching device with a large current parameter, which will inevitably increase the cost. FIG. 2 is a schematic diagram of a simulated waveform after the start-up of the infrared welding device in the related art. The alternating current is rectified by a rectifier circuit and an output voltage waveform 21 is produced. Waveform 22 is a control signal when the switching device S1 is switched. The waveform 23 is the current waveform of the infrared welding lamp 11 . When just started, the temperature of the infrared welding lamp 12 is very low, and the impedance is also very low, resulting in a large current flowing through the switching device S1 and the infrared welding lamp 12 when the switching device S1 is turned on. After a period of time, as the temperature of the infrared welding lamp tube rises rapidly, the impedance of the infrared welding lamp tube increases, and the current flowing through the switching device S1 and the infrared welding lamp tube 11 gradually decreases to a steady state value. Although the steady-state value of the infrared welding lamp is very small, due to the large starting current, the typical peak value of the starting current can reach 120A. the cost of.

Fig. 3 is a schematic circuit diagram of an infrared welding device according to an embodiment of the present invention. The switching device S2 is connected in series with the infrared welding lamp 32 at the output port of the rectifier circuit 31 , and the control terminal of the switching device S2 is connected to the controller 33 . In this embodiment, the rectification circuit 31 is a bridge rectification circuit including four diodes. It should be understood that the rectification circuit 31 may also adopt other existing rectification circuit forms, for example, a half-bridge rectification circuit or a rectification circuit composed of MOS transistors. In this embodiment, the switching device S2 is a metal oxide semiconductor transistor (Metal-Oxi de-Semiconductor Field-Effect Transistor, MOSFET). On the one hand, the MOSFET is used as the switch device to perform circuit on-off operation (that is, switching operation) at a relatively high frequency; on the other hand, the cost of the MOSFET is relatively low. In FIG. 3 , the controller 33 is connected to the gate of the switching device S2 to control the switching device S2 to be turned on or off. Under the control of the controller 33 , the switching device S2 can be switched at different frequencies, so as to control the current flowing through the infrared welding lamp 32 in different stages. Specifically, in the embodiment, the controller 33 is configured to control the switching device S2 to switch at the first frequency after starting, and control the switching device S2 to switch at the first frequency after the infrared welding lamp 31 is preheated. Two frequencies for switching. Wherein, the first switching frequency is greater than the second switching frequency. In the start-up phase, the high-frequency switching of the switching device S2 can reduce the start-up current flowing through the infrared welding lamp. After the infrared welding lamp is preheated and the impedance rises, switching to a lower second switching frequency can use the existing way to control the heating power of the infrared welding lamp. Adopting this control strategy can control the current flowing through the switching device during the entire working period, so that devices with lower requirements for current intensity can be selected to construct circuits, and the manufacturing cost of the device can be reduced. Specifically, in the start-up phase, the conduction time or duty cycle in each switching cycle is set according to the required current rise or current value. Since each cycle is shorter than that in normal working conditions, the rising range of the current in each cycle will be pulled down. At the same time, because the current will preheat the infrared welding lamp 31, its impedance value will increase with each cycle. The conduction of the gradually rises. Therefore, compared with low-frequency switching, the present embodiment effectively reduces the current peak value in the start-up phase by using higher-frequency switching. According to experiments, this embodiment can control the peak value of the start-up current below 16A.

In an optional implementation manner, the controller controls the switching device S2 to switch at the first frequency within a preset time period after the device is started, and controls the switching device S2 to switch at the second frequency after the preset time period passes. Specifically, the preset time period can be experimentally determined by preheating the time required for the infrared welding lamp tube to be preheated, and the controller 33 can be set. Generally speaking, the infrared welding lamp can be preheated in about 1 second to reach its working impedance. Therefore, the preset time period can be set to 1 second or greater than 1 second. After the preset period of time, the controller 33 enters the normal welding power control mode, at the second frequency, by controlling the conduction angle (that is, the ratio of the conduction time in each cycle or the duty cycle of the switch control signal ) to control the current intensity flowing into the infrared welding lamp tube 31, thereby controlling the power.

Therefore, in the embodiment of the present invention, the switching device is used to control the power conduction angle of the infrared welding lamp tube, and the controller is configured to control the switching device to switch at the first frequency within a preset period of time after the device is started. Switching is performed at the second frequency after the preset time period has elapsed. Thus, the start-up current of the infrared welding lamp can be controlled within a small range at the initial start-up of the device, and the power of the infrared welding lamp can be adjusted by controlling the conduction angle after the infrared welding lamp is preheated. Therefore, while ensuring the heating power of the infrared welding lamp tube, the cost is reduced and the infrared welding lamp tube and the switching device are effectively protected.

Fig. 4 is a schematic diagram of a simulation waveform after the infrared welding device of the embodiment of the present invention is started. The alternating current is rectified by the rectifier circuit to output a voltage waveform 41 . The waveform 42 is a control signal when the switching device S2 is switched at a first frequency within a preset period of time after the device is started. The waveform 43 is a control signal when the switching device S2 is switched at the second frequency after a preset period of time. The waveform 44 is the current waveform of the infrared welding lamp 32 within a preset time period. When starting up, the switching device S2 switches the switch at the first frequency, which reduces the starting current flowing through the infrared welding lamp and limits it within a small range. At the same time, during this period of time, the impedance of the infrared welding lamp gradually increases with the rapid rise of the temperature of the infrared welding lamp, and the current flowing through the switching device S2 and the infrared welding lamp 32 gradually decreases to a steady state value. After the preset time period, the switching device S2 is switched to a lower second frequency switching switch, and the waveform 45 is the current waveform of the infrared welding lamp 32 at this time.

Fig. 5 is a schematic diagram of a simulation waveform of intra-wave expansion after the infrared welding device is started according to the embodiment of the present invention. After the alternating current is rectified by the rectifier circuit, the output voltage expands within a waveform 51 . The waveform 52 is an intra-wave expanded waveform of the control signal when the switching device S2 switches the switch at the first frequency within a preset period of time after the device is started. The waveform 44 is an expanded waveform of the current wave of the infrared welding lamp 32 within a predetermined period of time. Immediately after start-up, since the switching device S2 switches the switch at the first frequency, each cycle is shorter than that in the normal working state, so the rising range of the current in each cycle will be pulled down, effectively reducing the current peak value in the start-up phase .

Fig. 6 is a schematic circuit diagram of another infrared welding device according to the embodiment of the present invention. The switching device S2 is connected to the output port of the rectifier circuit 61 in series with the infrared welding lamp 62 and the inductor L, and the switching device S2 is also connected to a controller 63 . Wherein, the rectification circuit 61 is a bridge rectification circuit including four diodes. The switch device is a metal oxide semiconductor transistor, and the controller 63 is connected to the gate of the switch device. The switching device S2 is controlled by the controller to perform switching at a first frequency and a second frequency respectively, and the first frequency is greater than the second frequency. Specifically, the controller controls the switching device S2 to switch at the first frequency within a preset time period after the device is started, and controls the switching device S2 to switch at the second frequency after the preset time period passes. Since the inductance has the function of hysteresis current greatly changes, after the inductance L, the device of this embodiment can further limit the current overcurrent and protect the switching device from being damaged, so that the current can be better limited when the device is started.

Fig. 7 is a flowchart of the driving of the infrared welding lamp according to the embodiment of the present invention. The process is applicable to the controller controlling the switch device connected in series with the infrared welding lamp. As shown in Figure 7, the drive of the infrared welding lamp in the embodiment of the present invention includes the following steps:

In step S710, the heating of the infrared welding lamp is started.

In step S720, the switching device S2 switches at a first frequency to limit the startup current.

Step S730, judging whether the preset time has been reached, if so, go to step S740, otherwise go to step S720.

In step S740, the switching device S3 switches at the second frequency to control the heating power.

Therefore, in the embodiment of the present invention, the switching is performed at the first frequency within a preset time period after the device is started, and the switching is performed at the second frequency after the preset time period has passed. Thus, the start-up current of the infrared welding lamp can be controlled within a small range at the initial start-up of the device, and the power of the infrared welding lamp can be adjusted by controlling the conduction angle after the infrared welding lamp is preheated. Therefore, while ensuring the heating power of the infrared welding lamp tube, the cost is reduced and the infrared welding lamp tube and the switching device are effectively protected.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. An infrared welding device, comprising:

a rectifier circuit configured to convert an input alternating current into a direct current;

welding a lamp tube by using infrared rays;

the switching device is connected with the infrared welding lamp tube in series at the output port of the rectifying circuit; and

a controller configured to control the switching device to switch at a first frequency after starting and to control the switching device to switch at a second frequency after preheating of the infrared welding lamp tube is completed;

wherein the first frequency is greater than the second frequency.

2. The apparatus of claim 1, wherein the switching device is a metal oxide semiconductor transistor.

3. The apparatus of claim 1, wherein the rectifier circuit is a bridge rectifier circuit.

4. The apparatus of claim 1, further comprising:

an inductive element in series with the switching device.

5. The apparatus of claim 1, wherein the controller is configured to control the switching device to switch at a first frequency for a preset time period after power-up, and to control the switching device to switch at a second frequency after the preset time period has elapsed.

6. The apparatus of claim 1, wherein the controller is configured to control a conduction angle of the switching device for each cycle according to a power control signal after the preset time period has elapsed.

7. A method of driving an ir-welded lamp tube for driving a switching device in series with the ir-welded lamp tube, the method comprising:

controlling the switching device to switch at a first frequency after being activated;

after the preheating of the infrared welding lamp tube is finished, controlling the switching device to switch at a second frequency;

wherein the first frequency is greater than the second frequency.

8. The method according to claim 7, wherein controlling the switching device to switch at the first frequency after start-up is in particular:

and controlling the switching device to switch at a first frequency within a preset time period after power-on.

9. The method of claim 7, further comprising:

and after the preset time period is over, controlling the conduction angle of each period of the switching tube device according to the power control signal.

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