Dispositivo de aquecimento à indução ressonante auto-oscilante com comutação em tensão zero

Abstract

Inductive heating is one of the key technologies for contemporary civilization, as it allows heating a material without direct contact with the workpiece and eliminates the need for oxygen during the process. This occurs because is heating through electromagnetic induction, not combustion, só the process can be carried out even in inert or vacuum atmospheres. Therefore, the goal of this project is to develop a portable induction heating device with adjustable power through voltage control via pulse-width modulation. For the development of the project, a comprehensive theoretical survey on the relevant topics was conducted, in addition to a series of experimental tests to evaluate and determine the most suitable circuit topology according to the specifications and available resources. The final prototype consists of a passive rectifier, a direct current to direct current converter, and a parallel resonant inductive-capacitive tank circuit with zero-voltage switching and self-oscillating, designed to operate with an input power of approximately 4 kW. In addition to the circuits, the device includes a liquid cooling system for the induction heating coil, which supports a refractory crucible intended for metal casting. The entire assembly is housed in a carbon steel metal structure, covered with stainless steel sheets, forming an enclosure that protects the electronic components and the control system. This control system provides real-time information about the equipment’s operation, including temperature monitoring to ensure the safety of the components and the adjustment of operating power. This induction heating equipment has potential applications in various metallurgical processes, such as casting, forging, normalization, hardening, and tempering of metals. The project aims to manufacture a portable device capable of heating small quantities of metal, offering a practical solution for metalworking shops, jewelry shops, cutlery workshops, metallurgical testing laboratories, and metallurgy enthusiasts in general.