Novel Type of Power Supply for Mid-Frequency Induction Heater in Industrial Thin Film Deposition Reactor

We reported the solution of the control problems of conventional power supply for mid-frequency induction heating in industrial thin film deposition reactor:including the low control accuracy, great current distortion, small power factor, large fluctuations of load resistance and phase, complicated control unit, incapability of cascading individual power supply, and importantly, non-uniform thickness. The solution was the modification of the conventional phase-shift frequency control with the frequency-sweeping amplitude-modulation control. The prototyped power supply with the modified control scheme has been field tested for over 3 years. The results show that the newly-developed power supply outperforms the conventional one because of higher control procession, lower distortion, more uniform heating and film thickness, greater productivity, and importantly, capability of cascading multiple power supplies as required. We suggest the new power supply be of some technological interest in coating industries.