Abstract

A new control method to catch the optimal working frequency (or driving frequency) for the high power ultrasonic welding system has been developed. During the high power operation, an ultrasonic resonant will induce high temperature and then change the working frequency. Therefore, a control method with a FPGA chip to track the optimal working frequency becomes very attractive and it has been practically implemented in this study. Generally, the FPGA chip includes two logic circuits, i.e. a logic circuit which manages the finding of optimal working frequency and the other one is to adjust the working frequency by detecting the working current simultaneously. Experimental results exhibit that the new method can effectively control and track frequency in the high power ultrasonic welding system. Due to this kind of study based on the FPGA design, it will enhance us the understanding of the physical realization in the ultrasound welding system.

Key words: Ultrasonic welding system, FPGA.