Primary constant current circuit of inverter welding machine

Abstract

The invention provides a primary constant current circuit of an inverter welding machine. The primary constant current circuit comprises a major loop and a control loop; the major loop comprises a double-pipe single-end forward circuit mainly comprising power switches Q3 and Q5, clamping diodes D3 and D4, a high-frequency isolation transformator T1, a sampling transformer T2, commutation diodes D10 and D11, free-wheeling diodes D12, D13 and D15 and an inductor L2; the control loop comprises two circuits, one circuit is a welding machine output short-circuit protection circuit, and in the other circuit, through regulation of a PI regulating circuit, a pulse signal output through a control signal can constantly regulate the pulse duty cycle, so that a welding machine can output constant current. According to the primary constant current circuit, the primary circuit is additionally arranged at the inverter welding machine, so that the constant current output characteristic of the welding machine is realized.

Description

technical field [0001] The invention relates to a circuit, more specifically, to a primary constant current circuit of an inverter welding machine. Background technique [0002] The inverter welding machine can use different output characteristics to realize different welding processes. For manual arc welding, it can adopt two characteristics of steep drop and slow drop, while for argon arc welding, it is ideal to use the steep drop characteristic. The multi-function of inverter welding machine is one direction. One machine has two functions of argon arc welding and manual electrode welding. For such a welding machine, it needs to adopt the steep drop characteristic to realize it. The steep drop characteristic requires the output of the welding machine to be controlled by constant current. At present, the most used method is to add a current Hall sensor to the output end of the welding machine to realize it. The cost is relatively high, and the sampling resistor is used to r...

AI Technical Summary

Problems solved by technology

The steep drop characteristic requires the output of the welding machine to be controlled by constant current. At present, the most used method is to add a current Hall sensor to the output end of the welding machine. The cost is relatively high, and the sampling resistor is used to achieve it, and the anti-interference ability is relatively poor.

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