A three-phase welding machine circuit

Abstract

The invention discloses a three-phase welder circuit which comprises a first isolation element, a second isolation element and a third isolation element; a primary circuit of a welder main circuit is connected with the input end of a three-phase power supply; the output end of a secondary circuit is an output end of a welder; a control circuit comprises a control unit and a signal enabling and extracting circuit; the control unit is used for controlling the primary circuit and the secondary circuit through the signal enabling and extracting circuit; the signal output end of a differential detection circuit is connected with the control unit; the input end of the differential detection circuit is connected with that of the three-phase power supply; the first isolation element is connected with the power ground of the control unit and a housing of the welder; the second isolation element is connected with an anode at the output end of the welder and the housing; and the third isolation element is connected with a cathode at the output end of the welder and the housing. According to the three-phase welder circuit, a heavy and high-cost power-frequency transformer is cancelled, the circuit structure is simple, the welder volume is small, the detection precision is high, and the welder cost can be reduced.

Description

[technical field] [0001] The invention relates to welding equipment, in particular to a three-phase welding machine circuit. [Background technique] [0002] The existing three-phase input welding machine generally adopts a system without a neutral line, and the input line voltage is relatively high, but the shell of the welding machine and the output voltage during actual welding are required to be within the safe voltage range, so the insulation requirements of the welding machine are very high. Strict, mainly reflecting the high withstand voltage requirements and high impedance requirements between input and output, input and ground, output and ground. Therefore, if you want to achieve high-precision input voltage detection, you must solve the requirements of high input impedance and high insulation withstand voltage required by the insulation system. [0003] The traditional three-phase input welding machine uses a power frequency transformer to isolate and step down the...

AI Technical Summary

Problems solved by technology

[0012] 1. The power frequency transformer is inherently bulky, and has non-negligible internal resistance characteristics that change with changes in external conditions, making the detection system with a power frequency transformer and a low voltage detection circuit inherently low in detection accuracy

[0013] 2. Due to the low detection accuracy and limited detection range, the protection point of the input voltage will be different under different working conditions. It is necessary to leave a certain margin for the whole system to avoid damage to other components of the welding machine system before protection.

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