Induction heating power supply and its technical (part 1)

Induction heating power supply and its technical (part 1)




Thyristor IF in power in power generator to replace the machine. The 20th century, the early 90s, the domestic thyristor power plants have sprouted and flourished everywhere, through the survival of the fittest competition, and now production plant has tended to stabilize. Thyristor Power now has the power to the IGBT transistor development, and tubes will be developed into a high-frequency power MOSFET transistors, transistors ultra-portable audio, high-frequency power supply market is extremely competitive, its future who will also be of high quality, technological level Gao, who will be able to gain a firm foothold.



Domestic intermediate frequency power supply are currently used parallel resonant power inverter structure. Therefore, greater capacity in research and development of parallel inverter frequency power supply at the same time, the development of simple structure, easy-to-frequent start of the series inverter frequency power supply is the area of medium-frequency induction heating device problems to be solved, especially in the melting, casting application , the series inverter easy to achieve full operating conditions constant power output (t help reduce the power consumption) and a Multi-load power distribution control, more worthy of popularization.



In the ultra-Audio (10 ~ 100kHz) within its own thyristor switching characteristics due to parameters such as restrictions to the development of the power of the band brings a great deal of technical difficulty. Although 80 years of Zhejiang University multiplier circuit using thyristor developed a 50kW / 50kHz ultra-audio power supply, was developed using the time division circuit of thyristor super-30kHz audio power, but because of the dual-resonant circuit multiplier circuit coupled to the load was non-linear, time-varying heat load parameters and parameter matching resonant circuit debugging very complex, and time division circuit to control and main circuit structure of complex, low utilization rate of power inverter control, it has not been well popularized.



70 to 80 early, it will be integrated in modern semiconductor micro-processing technology combined with the power semiconductor technology, have developed a large number of full-controlled power electronic semiconductor devices (GTR, MOSFET, SIT, SITH, and MCT, etc.), for all solid-state super-audio , high-frequency power supply development has laid a solid foundation.



In the high-frequency (100kHz and above) band, is currently abroad, is in the power supply from the traditional tube-based all solid-state power supply to the transistor transition period. Japan, some companies use SIT, the power level of 80 reached late 1000kW, 200kHz, 400kW, 400kHz.



In Europe and the United States, due to the presence of high-state SIT loss (SIT working in non-saturated zone) and other defects to high-frequency MOSFET-based power devices. With MOSFET power devices and modular, high capacity technology, MOSFET high-frequency induction heating power supply capacity has been rapid development. Spain's current-mode MOSFET using induction heating power supply manufacturers, up to 600kW, 400kHz, Germany, developed in 1989, current-mode MOSFET Induction Heating Power Supply, up to 480kW, 50 ~ 200kHz, Belgium I nductoEiphiac produced by current-mode MOSFET Induction Heating Power Supply levels can be up to 1000kW, 15 ~ 600kHz. Zhejiang University in the 90s developed 20kW, 300kHz MOSFET high-frequency power supply, has been successfully applied to the surface heat treatment of small tools and aircraft turbine blade thermal stress assessment.



At present, the induction heating power supply in the medium frequency band, used mainly thyristor, VHF band, used mainly IGBT, while in high-frequency band, due to the presence of high conduction losses SIT and other defects, a major international development MOSFET power supply. Although the use of induction heating power resonant inverter will help to achieve soft-switching power devices, but the induction heating power supply is usually larger on the power devices, passive components, cables, wiring, grounding and shielding, etc. are a number of special requirements. Therefore, to achieve high-frequency induction heating power supply of basic technology for many applications still need to be further explored, especially in the new high-frequency high-power devices (such as the MCT, IGBT power devices, and SIT, etc.) come out, will further promote the development of the high-frequency induction heating power supply.



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