The working principle of the intermediate frequency inverter resistance welding machine mainly involves converting the power frequency alternating current into the intermediate frequency direct current suitable for welding, and using resistive heat to realize the connection of metal workpieces. The specific process details are as follows:

AC power input: The intermediate frequency inverter resistance welding machine is usually connected to a 380V three-phase AC power supply to provide electrical energy to the welding machine. The three-phase alternating current has a phase difference, which can provide a more stable power output, ensuring that the welding machine can obtain continuous and sufficient energy during operation.

Rectification and filtering: The three-phase AC current input from the intermediate frequency inverter resistance welding machine first enters the rectifier circuit. The rectifier circuit is generally composed of multiple diodes, which can convert the three-phase AC current into DC power. Since there will be a certain current in the rectified DC current, it is necessary to filter through a filtering circuit. The filter circuit is generally composed of components such as capacitors and inductors, which can remove the pulsating components in the DC power, make the output DC voltage smoother, and provide a stable DC power supply for subsequent inverter processes.

Intermediate frequency inverter: The filtered DC current enters the inverter circuit. The inverter circuit is the core part of the intermediate frequency inverter resistance welding machine and is usually composed of high-power switching electronic components such as insulated gate bipolar transistors (IGBTs). These switching elements, under the action of the control circuit, alternately conduct and turn off at higher frequencies, convert the DC power supply to alternating intermediate frequency (usually in the range of 1kHz to 4kHz). By changing the on- and off-time ratio of the switching element, i.e., the pulse width modulation (PWM) technology, the output mid-frequency AC voltage and current can be accurately controlled.

Step-down output: The intermediate frequency alternating current is bucked by the intermediate frequency transformer to reduce the voltage to a suitable range of resistance welding, generally from several volts to dozens of volts. At the same time, according to the principle of electromagnetic induction, the current will increase accordingly during the step-down process, providing sufficient heat for welding. The medium-frequency transformer is characterized by small size, light weight and high efficiency. It can quickly respond to changes in current and ensure the stability and accuracy of the welding process.

Rectification output: The reduced intermediate frequency alternating current passes through the rectifying circuit again and converts it into DC, which is the power supply that is ultimately used for welding. Through this rectification process, the medium frequency inverter resistance welding machine can make the welding current more stable, reduce the impact of current fluctuations on the welding quality, ensure the stable output of heat during welding, and help form high-quality welding joints.