An inverter welding machine

Abstract

The invention provides an inverter welder, and belongs to the technical field of the welder. The problems that an existing inverter welder needs sine-input currents, and the width of input voltages is small are solved. The inverter welder comprises a PWM control circuit, a rectification filter circuit, an inverter circuit and a voltage-reduction rectification circuit, wherein the rectification filter circuit, the inverter circuit and the voltage-reduction rectification circuit are sequentially connected. The rectification filter circuit is connected with an outside power source, the voltage-reduction rectification circuit is connected with the output end of the welder, the rectification filter circuit is connected with the PWM control circuit through an input voltage feedback circuit, and the voltage-reduction rectification circuit is connected with the PWM control circuit through an output voltage feedback circuit. The inverter welder further comprises a boosting main circuit and a PFC control circuit which is connected with the boosting main circuit, the boosting main circuit is connected between the rectification filter circuit and the inverter circuit, and the rectification filter circuit is connected with the PFC control circuit through an input current feedback circuit. The inverter welder has the advantages that sine-input currents are of no need, and the wide voltage input can be achieved.

Description

technical field [0001] The invention belongs to the technical field of welding machines, and relates to an inverter electric welding machine. Background technique [0002] The existing inverter welding machine is to rectify and filter the three-phase alternating current to obtain a relatively smooth direct current, and the inverter circuit composed of power switching elements (usually IGBT or field effect tube, the same below) converts the direct current into 15 to 100kHz alternating current, after being stepped down by the intermediate frequency main transformer, rectified and filtered again to obtain a stable direct current output welding current or reinverted to output alternating current of the required frequency. [0003] The front-end diode rectifier of the traditional inverter welding machine seriously distorts the input current, which not only produces serious harmonic pollution to the power grid but also causes low power factor of the switching power supply. At the...

AI Technical Summary

Problems solved by technology

[0003] The front-end diode rectifier of the traditional inverter welding machine seriously distorts the input current, which not only produces serious harmonic pollution to the power grid but also causes low power factor of the switching power supply

At the same time, in traditional CCM active PFC controllers, such as UC3854, in this traditional controller, the error amplifier input voltage U needs to be multiplied by the sine wave reference model I to obtain the sinusoidal input current. This traditional CCM PFC circuit control must The sine wave reference signal is introduced, and due to the two control loops of the voltage loop and the current loop, there are many peripheral components of the control device, and the design is complicated

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