Energy-saving technology of intermediate frequency induction melting furnace
my country's intermediate frequency induction melting furnace industry is developing rapidly, and the level of domestically-made equipment is technically close to the highest level in the world. As a typical application, one drives two inverter furnaces. One rectifier with two inverters drives two electric furnaces of the same specification, so that the power of one inverter power supply can be flexibly distributed to two furnace bodies, that is, one The high power of the power supply is allocated to the melting furnace, and the remaining small power is allocated to the holding furnace, so as to realize "one melting and one heat preservation", so that the electric furnace system has the ability to continuously produce molten iron.

Temperature control technology
The intermediate frequency induction melting furnace adopts CPU calculation program and complex software compiled in high-level language. The basic function is to continuously monitor the output power of the intermediate frequency power supply, count the capacity sent to the electric furnace, and also monitor the ambient temperature, cooling water temperature and flow rate. Continuous monitoring is used to calculate the energy consumed by the electric furnace.
Constant power control technology
The series resonant power supply can adjust the impedance of the intermediate frequency power supply by adjusting the operating frequency of the intermediate frequency power supply. The change of the operating frequency can avoid directly changing the impedance of the electric furnace. When the impedance of the electric furnace is too low, the power frequency frequency can be appropriately increased. Reduce the operating frequency. Through this adjustment, the impedance of the electric furnace will be basically the same throughout the melting process, so as to ensure that the intermediate frequency power supply always works at the rated power.
Load matching research
Whether the load impedance matching is appropriate will directly affect the rated power of the power supply. The design and calculation of induction coil (load) are very complicated, and it is not easy to design a satisfactory load coil. At present, many domestic designs use formulas that ignore secondary parameters or rely on experience-corrected formulas, which have large errors.
High power due to low harmonics
The new generation power supply must be a power supply with high power factor and low harmonics. The current developing technologies include: multiple rectification technology, fully-controlled power tube plus matrix control or PWM control, series circuit, chopper technology, etc. At the same time, it also gave birth to the development and production of harmonic elimination devices for power harmonic filtering and power factor compensation.
Energy conservation
The electrical efficiency of a well-designed intermediate frequency induction melting furnace can usually reach 78% or more. Therefore, improving the melting efficiency of an induction furnace under the existing technical thinking is unlikely to achieve a large improvement. It is necessary to achieve substantial energy saving and emission reduction. It is necessary to make a fuss on the inductor and the charge system, break the existing framework, establish a new design model, and increase the electrical efficiency of the system to more than 90%.