90kW Medium-Frequency (MF) Melting Furnace

Product Overview

This medium frequency induction heating system is designed around the series-resonant inverter structure, consisting of a MF power supply, a compensation capacitor box, and a customized induction coil. It is a high-efficiency, cost-effective solution widely used in metal melting, heat treatment, and thermal fitting applications.

Technical Highlights

Technical Explanation

The system works on LC series resonance, where the induction coil (L) and capacitor box (C) form a resonant circuit. At resonance, impedance is minimized, and current is maximized—allowing efficient energy transfer to the workpiece via eddy current heating.

However, the design also has several limitations:

• Induction coil length is typically long (3–10 meters of copper tubing)
• The coil is directly connected to high-voltage output (up to 550V) and is not isolated from the grid
• In vacuum applications, the coil may cause glow discharge, so insulation is critical (high-temp tape, ceramic mud, varnish, or shielded enclosure required)

Main Applications and Features:

• It has a wide frequency range of 1KHZ--20KHZ, which can be matched according to the size of the specific heated workpiece or the requirements of heat penetration depth, thus having a large application range. It adopts the traditional medium-frequency parallel resonance structure, featuring simple load matching, high equipment efficiency and low energy consumption.
• The large SLZ series medium-frequency power supply adopts IGBT power devices and our company's fourth-generation converter control technology - dual-control converter control technology based on parallel resonance. In this technology, power and frequency conversion are independently controlled. It uses IGBT switching devices and amorphous inductors to form a high-frequency chopper circuit to adjust power, and adopts IGBT parallel resonance and automatic frequency tracking technology to achieve precise soft-switching control of the inverter process. This greatly improves the working reliability of the equipment under high power, promotes the development of the equipment in the high-power field, and realizes 100% equipment duty cycle.
• High efficiency and energy saving: It has extremely high power factor and power supply efficiency in the full power range. Compared with silicon-controlled medium-frequency equipment, it saves energy by at least 20%.
• The equipment is small in size, light in weight, and available in a complete range of models with a wide selection. It is suitable for use in factories, schools and research institutes.