Principle of electromagnetic heater:

An electromagnetic heater is a device that converts electrical energy into heat by utilizing the principle of electromagnetic induction. The electromagnetic controller converts 220V/380V, 50/60Hz AC power into DC through a rectifying circuit, then transforms it into a high-frequency current of 10-40kHz via a control circuit. As the current flows through the coil, it generates a varying alternating magnetic field. When the alternating magnetic lines in the field pass through ferromagnetic materials (such as iron, cobalt, and nickel), numerous tiny eddy currents are induced within the metal, causing the material to heat up rapidly, thereby achieving the purpose of heating the metal.

Inverters are the core components of high-frequency electromagnetic heaters, acting as control devices that convert power frequency AC power into another frequency of electrical energy through the on-off action of power semiconductor devices. The inverters currently in use mainly employ AC-DC-AC conversion, first converting the power frequency AC power into DC power through a rectifier, and then converting the DC power into an AC power supply with controllable frequency and voltage for the motor. The circuit of the inverter generally consists of four parts: rectification, intermediate DC link, inversion, and control. The rectification part is a three-phase bridge uncontrolled rectifier, the inversion part is an IGBT three-phase bridge inverter with PWM output, and the intermediate DC link is for filtering, DC energy storage, and reactive power buffering.