Infrared soldering device and driving method of infrared soldering lamp tube

Abstract

The embodiment of the present application discloses an infrared welding device and a driving method of an infrared welding lamp tube. The device is provided with a switching device to control the power conduction angle of the infrared welding lamp tube, and a controller is configured to control the switching device to switch at a first frequency within a preset time period after the device is started, and to switch at a second frequency after the preset time period, wherein the first frequency is greater than the second frequency. Thus, the starting current of the infrared welding lamp tube can be controlled within a very small range at the initial stage of the device, so that the heating power of the infrared welding lamp tube is ensured, the cost is reduced, and the infrared welding lamp tube and the switching device are effectively protected.

Description

Technical Field

[0001] This invention relates to the field of electronic and electrical technology, specifically to an infrared welding device and an infrared welding lamp driving method. Background Technology

[0002] As new clean energy sources become increasingly popular, solar photovoltaic panels are gaining popularity, and users are demanding higher power output from small photovoltaic cells. Since the voltage and power generated by each individual photovoltaic cell are relatively small and insufficient for practical applications, it is necessary to connect the cells in series and parallel by welding them together to achieve higher power output.

[0003] Infrared welding lamps are commonly used for heating solar cells. Current technology uses thyristors to control the conduction angle and adjust the heating power of the lamp. While this method is simple, the reliability of the driver power devices and the infrared welding lamps is unsatisfactory. Because the filaments of infrared welding lamps (such as tungsten iodide, quartz, and carbon fiber) often have a strong positive temperature coefficient, a 1kW quartz infrared welding lamp, for example, has an impedance of only 4-5 ohms at a filament temperature of 25℃, but can reach 40-50 ohms at a power of 1kW. During startup, the low filament impedance results in a large instantaneous current, which significantly impacts the lamp's lifespan and necessitates the use of higher-power devices, inevitably leading to larger size and higher cost. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an infrared welding device and an infrared welding lamp driving method, so as to effectively protect the infrared welding lamp and the driver power device at a lower cost while ensuring the heating power of the infrared welding lamp.

[0005] In a first aspect, an infrared welding apparatus is provided, the apparatus comprising:

[0006] A rectifier circuit is configured to convert input alternating current into direct current.

[0007] Infrared welding lamp tube;

[0008] A switching device is connected in series with the infrared welding lamp at the output port of the rectifier circuit; and

[0009] The controller is configured to control the switching device to switch at a first frequency after startup, and to control the switching device to switch at a second frequency after the infrared welding lamp tube has been preheated.

[0010] Wherein, the first frequency is greater than the second frequency.

[0011] Optionally, the switching device is a metal-oxide-semiconductor transistor.

[0012] Optionally, the rectifier circuit is a bridge rectifier circuit.

[0013] Optionally, the device further includes:

[0014] An inductor is connected in series with the switching device.

[0015] Optionally, the controller is configured to control the switching device to switch at a first frequency during a preset time period after power-on, and to control the switching device to switch at a second frequency after the preset time period has elapsed.

[0016] Optionally, the controller is configured to control the conduction angle of the switching device for each cycle according to the power control signal after the preset time period.

[0017] Secondly, a method for driving an infrared welding lamp is provided, the method comprising:

[0018] After startup, the switching device is controlled to switch at a first frequency;

[0019] After the infrared welding lamp tube has been preheated, the switching device is controlled to switch on and off at a second frequency.

[0020] Wherein, the first frequency is greater than the second frequency.

[0021] Optionally, controlling the switching device to switch at a first frequency after startup specifically involves:

[0022] After power-on, the switching device is controlled to switch at a first frequency within a preset time period.

[0023] Optionally, the method further includes:

[0024] After the preset time period, the conduction angle of the switching device is controlled for each cycle according to the power control signal.

[0025] This invention uses a switching device to control the power conduction angle of an infrared welding lamp, and configures a controller to control the switching device to switch at a first frequency for a preset time period after power-on, and then at a second frequency after the preset time period, where the first frequency is greater than the second frequency. Therefore, the starting current of the infrared welding lamp can be controlled within a very small range during the initial startup of the device. Once the temperature of the infrared welding lamp rises to a certain value, the power of the infrared welding lamp can be adjusted by controlling the conduction angle. This ensures the heating power of the infrared welding lamp while reducing costs and effectively protecting the infrared welding lamp and the driver power device. Attached Figure Description

[0026] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a circuit diagram of an infrared welding device based on a related technology.

[0028] Figure 2 This is a schematic diagram of the simulation waveform of an infrared welding device after startup, which is a related technology.

[0029] Figure 3 This is a circuit diagram of the infrared welding device according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the simulation waveform of the infrared welding device after startup according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the unfolded simulation waveform of the infrared welding device after startup according to an embodiment of the present invention;

[0032] Figure 6 This is a circuit diagram of another infrared welding device according to an embodiment of the present invention;

[0033] Figure 7 This is a flowchart of the infrared welding lamp driving process according to an embodiment of the present invention. Detailed Implementation

[0034] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0035] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0036] Unless the context explicitly requires it, words such as "including" or "contains" in the instruction manual should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0037] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] In this specification, “start-up” means starting up the infrared welding lamp without preheating it.

[0039] Figure 1 This is a circuit diagram of an infrared welding device based on a related technology. Figure 1 As shown, the switching device S1 is connected in series with the infrared welding lamp 12 at the output port of the rectifier circuit 11. The rectifier circuit 11 converts the input AC power AC1 into DC power. The switching device S1 controls the power conduction angle of the infrared welding lamp 12, thereby adjusting the heating power of the infrared welding lamp. The rectifier circuit 11 is a bridge rectifier circuit including four diodes. In this infrared welding device, since the switching devices used are typically IGBTs or BJTs (Bipolar Junction Transistors-BJTs), the reliability of the infrared welding lamp and the switching devices is poor, which greatly affects the lifespan of the infrared welding lamp. Furthermore, switching devices with high current parameters are required, which inevitably increases the cost. Figure 2 This is a simulation waveform diagram of the infrared welding device after startup. Waveform 21 shows the output voltage after the AC power is rectified by the rectifier circuit. Waveform 22 is the control signal when the switching device S1 switches. Waveform 23 is the current waveform of the infrared welding lamp 11. At startup, the temperature and impedance of the infrared welding lamp 12 are very low, resulting in a large current flowing through both the switching device S1 and the infrared welding lamp 12 when the switching device S1 is turned on. After a period of time, due to the rapid rise in temperature and the increase in impedance of the infrared welding lamp, the current flowing through the switching device S1 and the infrared welding lamp 11 gradually decreases to a steady-state value. Although the steady-state value of the infrared welding lamp is small, the startup current is very large, typically reaching a peak current of 120A. Therefore, a switching device with a very high current parameter is required, which inevitably leads to a larger size and higher cost.

[0040] Figure 3This is a circuit diagram of the 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 rectifier circuit 31 is a bridge rectifier circuit including four diodes. It should be understood that the rectifier circuit 31 can also adopt other existing rectifier circuit forms, such as a half-bridge rectifier circuit or a rectifier circuit composed of MOSFETs. In this embodiment, the switching device S2 is a metal-oxide-semiconductor transistor (MOSFET). Using a MOSFET as the switching device allows for circuit switching operations (i.e., switching operations) at higher frequencies, and MOSFETs are also less expensive. Figure 3 In this embodiment, controller 33 is connected to the gate of switching device S2 to control the switching device S2 to turn on or off. Under the control of controller 33, switching device S2 can switch at different frequencies, thereby controlling the current flowing through infrared welding lamp 32 at different stages. Specifically, in this embodiment, controller 33 is configured to control switching device S2 to switch at a first frequency after startup, and to control switching device S2 to switch at a second frequency after the infrared welding lamp 31 has preheated. The first switching frequency is greater than the second switching frequency. The high-frequency switching of switching device S2 during startup can reduce the startup current flowing through the infrared welding lamp. After the infrared welding lamp has preheated and its impedance has increased, switching to the lower second switching frequency allows for the control of the heating power of the infrared welding lamp using existing methods. This control strategy allows the current flowing through the switching device to be controlled throughout the entire operation, thereby allowing the selection of devices with lower current requirements to construct the circuit and reducing the manufacturing cost of the device. Specifically, during startup, the on-time or duty cycle in each switching cycle is set according to the required current rise or current value. Because each cycle is shorter than under normal operating conditions, the current rise in each cycle is reduced. Simultaneously, as the current preheats the infrared welding lamp 31, its impedance gradually increases with each cycle. Therefore, compared to low-frequency switching, this embodiment effectively reduces the peak current during startup by using a higher frequency of switching. Experiments show that this embodiment can control the peak startup current below 16A.

[0041] In one optional implementation, after the device is started, the controller controls the switching device S2 to switch at a first frequency for a preset time period. After the preset time period, the controller controls the switching device S2 to switch at a second frequency. Specifically, the preset time period can be determined experimentally by preheating the infrared welding lamp and the controller 33 can be set accordingly. Generally, the infrared welding lamp can be preheated to its operating impedance in about 1 second. Therefore, the preset time period can be set to 1 second or more. After the preset time period, the controller 33 enters the normal welding power control mode. At the second frequency, the controller controls the current intensity flowing into the infrared welding lamp 31 by controlling the conduction angle (i.e., the proportion of conduction time in each cycle or the duty cycle of the switching control signal), thereby controlling the power.

[0042] Therefore, this embodiment of the invention controls the power conduction angle of the infrared welding lamp using a switching device, and configures a controller to control the switching device to switch at a first frequency within a preset time period after the device is started, and then switch at a second frequency after the preset time period. This allows the starting current of the infrared welding lamp to be controlled within a very small range during the initial startup of the device, and the power of the infrared welding lamp can be adjusted by controlling the conduction angle after the infrared welding lamp has preheated. This ensures the heating power of the infrared welding lamp while reducing costs and effectively protecting the infrared welding lamp and the switching device.

[0043] Figure 4 This is a schematic diagram of the simulated waveforms after the infrared welding device of this embodiment of the invention is started. The AC power outputs voltage waveform 41 after rectification by the rectifier circuit. Waveform 42 is the control signal of the switching device S2 switching at a first frequency within a preset time period after the device starts. Waveform 43 is the control signal of the switching device S2 switching at a second frequency after the preset time period. Waveform 44 is the current waveform of the infrared welding lamp 32 within the preset time period. Upon startup, the switching device S2 switches at the first frequency, reducing the starting current flowing through the infrared welding lamp and limiting it to a very small range. Simultaneously, during this time period, the impedance of the infrared welding lamp gradually increases as the temperature of the infrared welding lamp rises rapidly, 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 switches to the lower second frequency, and waveform 45 is the current waveform of the infrared welding lamp 32 at this time.

[0044] Figure 5This is a schematic diagram of the intrawavelength expansion simulation waveform of the infrared welding device after startup according to an embodiment of the present invention. The output voltage of the AC power after rectification by the rectifier circuit is waveform 51. Waveform 52 is the intrawavelength expansion waveform of the control signal when the switching device S2 switches at a first frequency within a preset time period after device startup. Waveform 44 is the intrawavelength expansion waveform of the current of the infrared welding lamp 32 within the preset time period. Immediately after startup, because the switching device S2 switches at the first frequency, each cycle is shorter than under normal operating conditions. Therefore, the current rise in each cycle is reduced, effectively lowering the current peak during startup.

[0045] Figure 6 This is a circuit diagram of another infrared welding device according to an embodiment of the present invention. A switching device S2, an infrared welding lamp 62, and an inductor L are connected in series at the output port of a rectifier circuit 61. The switching device S2 is also connected to a controller 63. The rectifier circuit 61 is a bridge rectifier circuit with four diodes. The switching device is a metal-oxide-semiconductor transistor, and the controller 63 is connected to the gate of the switching device. The switching device S2 can be switched at a first frequency and a second frequency, controlled by the controller, where the first frequency is greater than the second frequency. Specifically, after the device is started, the controller controls the switching device S2 to switch at the first frequency for a preset time period, and after the preset time period, controls the switching device S2 to switch at the second frequency. Because the inductor has the effect of delaying large changes in current, after the inductor L, the device of this embodiment can further limit overcurrent and protect the switching device from damage, thereby better limiting the current when the device is started.

[0046] Figure 7 This is a flowchart illustrating the driving process of an infrared welding lamp according to an embodiment of the present invention. The flowchart is applicable to controllers controlling switching devices connected in series with the infrared welding lamp. Figure 7 As shown, the infrared welding lamp driving method of this embodiment of the invention includes the following steps:

[0047] Step S710: Infrared welding lamp heating is started.

[0048] In step S720, the switching device S2 switches at a first frequency to limit the starting current.

[0049] Step S730: Determine whether the preset time has been reached. If yes, proceed to step S740; otherwise, proceed to step S720.

[0050] In step S740, the switching device S3 switches on and off at a second frequency to control the heating power.

[0051] Therefore, in this embodiment of the invention, the device switches on and off at a first frequency for a preset time period after startup, and then switches on and off at a second frequency after the preset time period. This allows the starting current of the infrared welding lamp to be controlled within a very small range during the initial startup phase of the device. After the infrared welding lamp has preheated, its power is adjusted by controlling the conduction angle. This ensures the heating power of the infrared welding lamp while reducing costs and effectively protecting the infrared welding lamp and switching devices.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. An infrared welding device, characterized in that, The device includes: A rectifier circuit is configured to convert input alternating current into direct current. Infrared welding lamp tube; A switching device is 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 within a preset time period after power-on, the preset time period being determined by the time required for the infrared welding lamp to preheat, and to control the switching device to switch at a second frequency after the infrared welding lamp has preheated. Wherein, the first frequency is greater than the second frequency; The controller is configured to control the conduction angle of the switching device for each cycle according to the power control signal after the preset time period. The conduction angle is used to characterize the proportion of conduction time in each cycle or the duty cycle of the switch control signal. The proportion of conduction time in each cycle or the duty cycle is set according to the required current rise or current value.

2. The apparatus according to claim 1, characterized in that, The switching device is a metal-oxide-semiconductor transistor.

3. The apparatus according to claim 1, characterized in that, The rectifier circuit is a bridge rectifier circuit.

4. The apparatus according to claim 1, characterized in that, The device further includes: An inductive element is connected in series with the switching device.

5. A method for driving an infrared welding lamp, used to drive a switching device connected in series with the infrared welding lamp, characterized in that, The method includes: After power-on, the switching device is controlled to switch at a first frequency within a preset time period, the preset time period being determined by the time required for the infrared welding lamp to preheat; After the infrared welding lamp tube has been preheated, the switching device is controlled to switch on and off at a second frequency. After the preset time period, the conduction angle of the switching device is controlled for each cycle according to the power control signal; Wherein, the first frequency is greater than the second frequency, and the conduction angle is used to characterize the proportion of conduction time in each cycle or the duty cycle of the switch control signal. The proportion of conduction time in each cycle or the duty cycle is set according to the required current rise or current value.

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