逆变器 焊机使用亚毫秒脉冲宽度调制（切换）技术以及 闭环 feedback to control the weld energy in submillisecond increments. Three phase input current is full wave rectified to DC and switched at (up to) 25 kHz to produce an AC current at the primary of the welding transformer. The secondary current is then rectified to produce DC welding current with an imposed, low-level, AC ripple. The high-speed feedback circuitry enables the inverter power supply to adapt to changes in the secondary loop resistance and the dynamics of the welding process.
For example, a 25 kHz inverter power supply adjusts the output current every 20 microseconds after rectification, which also allows the weld time (duration of current) to be controlled accurately in increments as small as 0.1 milliseconds. The high frequency closed loop feedback can be used to control (maintain constant) either current, voltage, or power while also monitoring another of the same three parameters. Additional benefits of high frequency switching technology include reduced power consumption, smaller welding transformers, and the use of a very short pre-weld 'check pulse' to test electrode and parts positioning prior to executing a weld. The result of this pre-weld check can be used to inhibit the weld by setting check limits.
如欲了解有关电阻焊工艺的更多信息，请阅读我们的 《电阻焊基本原理》 和 闭环反馈控制在焊接工艺中的优势。