Chopper drive circuit for lithium battery welding machine

Abstract

The utility model discloses a lithium electric welding machine chopper drive circuit belongs to drive circuit technical field, including pulse generation controller, photo -coupler drive module, chopper power device, pulse generation controller output signal source generates control pulse signal to photo -coupler, this photo -coupler obtains pulse signal and exports to transistor Q1 and transistor Q2, transistor Q1 and transistor Q2 according to the level state of photo -coupler output signal, the conduction and cut -off of control circuit, transistor Q1 and transistor Q2 drive field effect transistor Q3 and field effect transistor Q4 provide drive signal for chopper power device, the drain electrode of field effect transistor Q3 is connected with power VCC, and the source is connected with chopper power device, the drain electrode of field effect transistor Q4 is connected with chopper power device, and the source is grounded.

Description

Technical Field

[0001] This utility model relates to a driving circuit, and more particularly to a chopper driving circuit for a lithium battery welding machine, belonging to the field of driving circuit technology. Background Technology

[0002] Currently, lithium battery welding machine chopper drives typically use direct optocoupler driving. The maximum driving current of commercially available optocouplers is five amps, which is insufficient for high-power lithium battery welding machines. This can easily damage the chopper power devices, resulting in a high failure rate and affecting the quality of the welding machine. Therefore, a lithium battery welding machine chopper drive circuit is designed to solve the above problems. Utility Model Content

[0003] The main purpose of this invention is to provide a chopper drive circuit for lithium battery welding machines.

[0004] The objective of this utility model can be achieved by adopting the following technical solution:

[0005] The chopper drive circuit for a lithium battery welding machine includes a pulse generator controller, an optocoupler drive module, and chopper power devices.

[0006] The pulse generator controller outputs a signal source to generate a control pulse signal to the optocoupler;

[0007] The optocoupler acquires pulse signals and outputs them to transistors Q1 and Q2;

[0008] Transistor Q1 and transistor Q2 control the circuit to turn on and off according to the level of the output signal of the optocoupler;

[0009] Transistors Q1 and Q2 drive field-effect transistors Q3 and Q4 to provide drive signals for the chopper power device;

[0010] The drain of the field-effect transistor Q3 is connected to the power supply VCC, and the source is connected to the chopper power device.

[0011] The drain of the field-effect transistor Q4 is connected to the chopper power device, and the source is grounded.

[0012] Preferably, the pulse generator controller includes a PWM control chip SG3525. The VCC terminal of the PWM control chip SG3525 is electrically connected to one end of resistor R306 and one end of resistor R307. The other ends of resistors R307 and R306 are electrically connected to the anode of polarized capacitor C304, and the cathode of polarized capacitor C304 is grounded.

[0013] One end of resistor R306 and one end of resistor R307 are also connected to one end of capacitor C305 and connected to a 12V power supply;

[0014] Terminal 11 of the PWM control chip SG3525 is electrically connected to the anode of diode D301. The cathode of diode D301 is electrically connected to resistors R111 and R110, and capacitor C100. Terminal 14 of the PWM control chip SG3525 is electrically connected to the anode of diode D302. The cathode of diode D302 is also electrically connected to resistors R111 and R110, and capacitor C100.

[0015] Preferably, terminal 7 of the PWM control chip SG3525 is electrically connected to one end of resistor R308, terminal 5 of the PWM control chip SG3525 is electrically connected to one end of capacitor C306 and the other end of resistor R308, terminal 6 of the PWM control chip SG3525 is electrically connected to one end of resistor R309, the other end of resistor R309 is grounded, and terminals 1 and 12 of the PWM control chip SG3525 are electrically connected to the other end of capacitor C306 and grounded.

[0016] Preferably, the optocoupler drive module includes an optocoupler U101, wherein the two terminals of the optocoupler U101 are electrically connected to one end of a resistor R109, and the other end of the resistor R109 is electrically connected to the other end of a resistor R110 and to the other end of a capacitor C100.

[0017] Preferably, terminals 5-8 of optocoupler U101 are electrically connected to one end of capacitor C102, the anode of polarized capacitor C101, and the cathode of Zener diode Z101. The anode of Zener diode Z101, the cathode of polarized capacitor C101, and the other end of capacitor C102 are interconnected. One end of capacitor C102 is also electrically connected to one end of resistor R101, and the other end of resistor R101 is electrically connected to an 18V power supply.

[0018] The beneficial technical effects of this utility model are as follows:

[0019] The chopper drive circuit for lithium-ion welding machines provided by this utility model utilizes optocoupler isolation and a two-stage push-pull drive to increase the drive power to a maximum of fifteen amps. This increases the power by two to three times compared to traditional drive schemes, broadens the high-power design of lithium-ion welding machines, and improves the quality and stability of lithium-ion welding. Attached Figure Description

[0020] Fig. 1 This is a circuit diagram of a preferred embodiment of the chopper drive circuit for a lithium-ion welding machine according to the present invention;

[0021] Fig. 2 This is an overall circuit diagram of a preferred embodiment of the chopper drive circuit for a lithium-ion welding machine according to the present invention;

[0022] Fig. 3This is a pulse diagram of a preferred embodiment of the chopper drive circuit for a lithium-ion welding machine according to the present invention. Detailed Implementation

[0023] To enable those skilled in the art to understand the technical solution of this utility model more clearly, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of this utility model is not limited thereto. Example

[0024] like Figs. 1-3 As shown, the chopper drive circuit for the lithium-ion welding machine provided in this embodiment uses a PWM control chip SG3525. Capacitor C306 and resistor R309 form an oscillation frequency of 39kHz to generate pulse signals. The pulse square wave signals output from pins 11 and 14 drive pin 2 of optocoupler U101 via diodes D301 and D302 and resistors R110 and R109. The signal output from pin 6 of optocoupler U101 first passes through two transistors Q101 (NPN type) and Q102 (PNP type) to form a front-end push-pull drive, and then through two field-effect transistors Q103 (PNP type) and Q104 (NPN type) to form a rear-end push-pull drive. The chopper power device works as follows: A switching transformer is used, with a separate 18-23V voltage (the conduction voltage of the IGBT and MOSFET) to power the driving transistors and MOSFETs. A Zener diode Z104 forms a negative voltage. When the control signal output from pin 6 of optocoupler U101 is in the positive half-cycle, transistor Q101 and MOSFET Q104 conduct to drive power device Q301. When the control signal output from pin 6 of optocoupler U101 is in the negative half-cycle, transistor Q102 and MOSFET Q103 conduct to drive power device Q301. Thus, each pulse signal turns on power device Q301.

[0025] (IGBT single transistor or MOSFET), waveform as follows Fig. 3 As shown. Example

[0026] This embodiment will describe in detail the construction, debugging and application process of the chopper drive circuit of the lithium battery welding machine, so as to help technicians understand and practice the circuit more clearly.

[0027] The PWM control chip SG3525 is selected as the core chip of the pulse generator controller. This chip features high stability and good control accuracy, meeting the circuit's requirements for pulse signals. The optocoupler U101 is a 6N137 high-speed optocoupler, which offers fast transmission speed and good isolation performance, effectively ensuring accurate transmission of control signals. The chopper power device is an IRFP460 field-effect MOSFET, with a drain-source breakdown voltage of 500V and a continuous drain current of 20A, suitable for the power requirements of this circuit.

[0028] Regarding resistors, according to the circuit design, R306 and R307 are 1kΩ metal film resistors, R308 is a 3.9kΩ resistor, and R309 is a 100Ω resistor, etc., to ensure that the voltage and current at each node meet the design requirements. Capacitors C304 and C305 are 47μF / 35V electrolytic capacitors for power supply filtering; C306 is a 472 (4700pF) ceramic capacitor, which, together with resistor R309, generates an oscillation frequency of 39kHz. Diodes D301 and D302 are 1N4148 switching diodes, which have a fast switching speed and can meet the requirements for pulse signal transmission.

[0029] Based on the circuit schematic, a printed circuit board (PCB) is designed using professional PCB design software (such as Altium Designer). During the design process, component placement and routing rules are carefully considered, separating power components and control components to reduce mutual interference. Simultaneously, power and signal traces are rationally planned to ensure short and wide lines, reducing line resistance and inductance. The completed PCB undergoes rigorous electrical testing to ensure there are no short circuits, open circuits, or other issues.

[0030] Before soldering, clean and pre-treat the leads of all components to ensure soldering quality. Using a soldering iron and solder wire, solder each component onto the PCB in sequence, following the markings on the PCB. For chip components, use a hot air gun or a dedicated chip soldering tool to ensure good contact between the leads and the pads. During soldering, carefully control the soldering temperature and time to avoid damaging the components due to overheating.

[0031] After soldering, carefully inspect the soldering of each component in the circuit to ensure there are no cold solder joints or missing solder joints. Use a multimeter to perform static testing on the circuit, measuring the resistance values ​​of each critical node to check for short circuits or open circuits. Simultaneously, check the power input and output connections to ensure the circuit is in a safe state before power is applied.

[0032] Connect to both 12V and 18V power supplies and use a multimeter to measure the power supply output voltage to ensure it is stable and meets design requirements. Check the voltage across the power supply filter capacitor and observe for any abnormal fluctuations. If the voltage is unstable or abnormal, check whether the components in the power supply circuit are damaged or poorly soldered.

[0033] Connect an oscilloscope to pins 11 and 14 of the PWM control chip SG3525 and observe the output pulse square wave signal. Check if the signal frequency is 39kHz and if the duty cycle meets design expectations. The frequency of the pulse signal can be fine-tuned by adjusting the values ​​of resistor R309 and capacitor C306. If the signal is abnormal, check if the components in the oscillation circuit are working properly.

[0034] Connect an oscilloscope to pin 6 of optocoupler U101 and observe the output signal. With the PWM control chip outputting a normal pulse signal, the optocoupler should transmit the signal accurately. Check if the input and output signals of the optocoupler are synchronized and if there is any delay or distortion. If the optocoupler drive is abnormal, check the connections and component parameters of the optocoupler and its surrounding circuitry.

[0035] Check the operating status of the pre-stage push-pull driver (composed of transistors Q101 and Q102) and the post-stage push-pull driver (composed of MOSFETs Q103 and Q104) sequentially. Use an oscilloscope to observe the base (or gate) and collector (or drain) signals of each stage of the driver transistors to ensure that the driver transistors can conduct and cut off normally under the control of the optocoupler output signal. Adjust the bias resistors of the driver transistors to optimize the amplitude and waveform of the drive signal, ensuring that the chopper power device receives a sufficient and stable drive signal.

[0036] The debugged chopper drive circuit was applied to a lithium battery welding machine. Appropriate welding materials and welding process parameters were selected, and actual welding tests were conducted. The stability of the arc, the formation of the weld pool, and the quality of the weld joint were observed during the welding process. The circuit's adaptability to different welding conditions was evaluated by changing parameters such as welding current and welding time. If the welding quality was unsatisfactory, the cause was analyzed to determine whether it was a circuit problem or a welding process problem, and corresponding adjustments were made.

[0037] During continuous welding, monitor the temperature changes of each part of the circuit and check for overheating. Run the welding machine for extended periods to observe the stability of the chopper drive circuit, checking for abnormal noise, signal fluctuations, or component damage. If insufficient circuit stability is found, check the heat dissipation measures and whether components are aging.

[0038] Simulate different working environments and load conditions, such as changing the material and thickness of the welding material, and the operating frequency of the welding machine, to test the performance of the chopper drive circuit under various operating conditions. Record the circuit's operating parameters and welding results under different conditions to analyze the circuit's reliability and adaptability. Based on the test results, further optimize and improve the circuit to meet various needs in practical applications.

[0039] The above description is only a further embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope disclosed by the present utility model, based on the technical solution and concept of the present utility model, shall fall within the protection scope of the present utility model.

Claims

1. A chopper drive circuit for a lithium battery welding machine, characterized in that: Includes pulse generator controller, optocoupler drive module, and chopper power device; The pulse generator controller outputs a signal source to generate a control pulse signal to the optocoupler; The optocoupler acquires pulse signals and outputs them to transistors Q1 and Q2; Transistor Q1 and transistor Q2 control the circuit to turn on and off according to the level of the output signal of the optocoupler; Transistors Q1 and Q2 drive field-effect transistors Q3 and Q4 to provide drive signals for the chopper power device; The drain of the field-effect transistor Q3 is connected to the power supply VCC, and the source is connected to the chopper power device. The drain of the field-effect transistor Q4 is connected to the chopper power device, and the source is grounded.

2. The chopper drive circuit for a lithium-ion welding machine according to claim 1, characterized in that: The pulse generator controller includes a PWM control chip SG3525. The VCC terminal of the PWM control chip SG3525 is electrically connected to one end of resistor R306 and one end of resistor R307. The other ends of resistors R307 and R306 are electrically connected to the anode of polarized capacitor C304, and the cathode of polarized capacitor C304 is grounded. One end of resistor R306 and one end of resistor R307 are also connected to one end of capacitor C305 and connected to a 12V power supply; Terminal 11 of the PWM control chip SG3525 is electrically connected to the anode of diode D301. The cathode of diode D301 is electrically connected to resistors R111 and R110, and capacitor C100. Terminal 14 of the PWM control chip SG3525 is electrically connected to the anode of diode D302. The cathode of diode D302 is also electrically connected to resistors R111 and R110, and capacitor C100.

3. The chopper drive circuit for a lithium-ion welding machine according to claim 2, characterized in that: The 7th terminal of the PWM control chip SG3525 is electrically connected to one end of the resistor R308. The 5th terminal of the PWM control chip SG3525 is electrically connected to one end of the capacitor C306 and the other end of the resistor R308. The 6th terminal of the PWM control chip SG3525 is electrically connected to one end of the resistor R309, and the other end of the resistor R309 is grounded. The 1st and 12th terminals of the PWM control chip SG3525 are electrically connected to the other end of the capacitor C306 and grounded.

4. The chopper drive circuit for a lithium-ion welding machine according to claim 3, characterized in that: The optocoupler drive module includes an optocoupler U101, wherein the two terminals of the optocoupler U101 are electrically connected to one end of a resistor R109, and the other end of the resistor R109 is electrically connected to the other end of a resistor R110 and to the other end of a capacitor C100.

5. The chopper drive circuit for a lithium-ion welding machine according to claim 4, characterized in that: The 5-8 terminals of the optocoupler U101 are electrically connected to one end of capacitor C102, the anode of the polarized capacitor C101, and the cathode of the Zener diode Z101. The anode of the Zener diode Z101, the cathode of the polarized capacitor C101, and the other end of capacitor C102 are interconnected. One end of capacitor C102 is also electrically connected to one end of resistor R101, and the other end of resistor R101 is electrically connected to an 18V power supply.

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