60Hz용 변압기를 이용한 인버터 AC 스폿용접시스템의 용접시간 최소화

Abstract

This paper deals with a welding time minimization technique for a resistance spot welding system. Resistance spot welding system using SCR thyristors has some disadvantages of slow speed and low quality precise current control. Therefore, the use of inverter type welding system is increasing. In order to minimize the welding time of the inverter type system, conventional welding machine adopts high frequency transformer or several tens of switching devices connected in parallel. The system guarantees a short welding time, however, the driver system for the parallel connected switching devices is complex. This paper proposed a simplified inverter system for welding. The scheme adopts a full-bridge inverter with four IGBTs and conventional 60 [Hz] transformer. The output characteristics of the proposed system is analyzed with the variation of inverter output frequency and transformer impedence. The simulation and experimental results show that the welding time can be minimized to 2.5 [ms] with the proposed scheme.