산업용 디지털 인버터의 개발 및 그 적용

Abstract

Nowdays, an inverter technique is important in industrial fields. Especially, in the welding industry field, the inverter technique is the core of technology. A thyristor-type welding machine has been used until now. But a share of thyristor-type welding machine has been decreased by development of an inverter-type welding machine. The inverter-type welding machine has lighter weight and higher welding quality than the thyristor-type machine. In spite of these advantages, an inverter technique is still inadequate and has some problems yet. In this thesis, the development results of digital inverter (DI) and its applications are introduced. A simple PI controller is proposed to make the output current track the constant setting current. Based on microprocessor (PIC16F73), the control system is designed and developed. The developed digital inverter is applied to welding machine and Brown gas generator. In the application of DI to welding machine, a hot-start function, an anti-stuck function and a standby mode are included in the developed digital welding machine (DDWM). The DDWM increases welding quality and saves more power energy than a conventional welding machine. The DDWM is changed from the ready mode into the standby mode automatically 2 minutes after welding is stopped. Moreover, the DDWM increases welding quality, productivity and reduces costs of welding. So, the DDWM can have a great of contribution to the mobile welding industries. The effectiveness of the DDWM was proven by the simulations and experimental results. In the application of DI to Brown gas generator (BGG), a soft-start function is included in the developed BGG (DBBG). DBBG increases an efficiency of generation. The effectiveness of DBBG was also proven by the simulations and experimental results.