Ultra High Frequency IGBT Inverter

This might help....

http://www.academia.edu/3414762/Effect_of_the_driver_parameters_on_the_switching_losses_of_the_IGBT_switch_at_high_frequency_high_power_applications

Why do you want to use such a high frequency for an induction heating system that large?

The big industrial systems don't use frequencies much over a 1/10 if what you are proposing and even then at those frequencies the induction coil and related circuits are very fussy about their design and layout.

Also what power source are you planning to run this from?

Mr. tcmtech -

Why use "high frequency"?

By using high frequency, one can increase also increase or improve the efficiency of the induction heater. The "skin effect" phenomena comes into the picture when working with a high frequency switched device. The OP maybe considering that electrical characteristic and want to use it in his plan?

I have access to a good used commercial unit in the 50 KW working capacity range that works at 30 KHz.

Here is the writeup I did on it a while back. http://cr4.globalspec.com/thread/83867

I don't follow the necessity for using frequencies much higher than that unless its for highly specialized applications and if so there is a reason that the parts and circuit designs for such a unit are expensive!

To my knowledge IGBTs have ferquency limitations. Though tehy do claim 100 KHz on paper, there is serious derating issue and cannot operate beyond 10 to 20 KHz for bulk power. MOSFETS are best around 500KHz. But I have handled 50KW at nearly 10MHz or so - but they are all microwave vacuum tube oscilaltors- even today. Note all microwave devices (Klystorn, Magnetron, Tarvellingwave tubes) are still vacuum tubes. So you need to revise & relook at your requirements. How and why did you come up with 400 KHz and why and how 50 Kw and so on.

Dear Sir,

Thank you for the reply, This 50 Kw Power rating is based on the result we got from Valve operated High freq. invertor, which we used to harden a thin liner of 45mm OD and 38mm ID having a height of 30mm.

Actual results at 44 KW were 1,7mm depth @ 400 KHz freq in 5.7 secs for EN8 forged job.Hence we have arrived at this value. Since the wall thickness is very less, almost 300deg temperature is present on the OD of liner which has been confirmed with thermal crayon, anf there is also HAZ beyond 1.7mm. hence it is confirmed that

400 KHz is the right frequency.Since the recurring cost of valve is high we decided to go for IGBT based invertor, since mosfet technology is best suitable for power raring upto 20 KW Max, and high voltage mosfets (1200) volts are not available,

Dear Sir,

Thank you for the reply, We have proved the sample job of 24.9mm bore dia and 31.7 mm Outer Dia by a three turn coil using 450 Khz frequency and 32 KW power on valve type power source,But since the life of valve is almost less than 2 years, we would like to go for a mosfet based power source,

I want to know if the freq. can be atleat 300 KHZ and power 40 KW by using mosfets?

MOSFETs can certainly work at these high frequencies. Paralleling MOSFETs has another advanatge If due to some mismatch, one MOSFET takes more current and gets hotter, the condcuting resistance increases and current reduces and MOSFET cools down- so soem kind of an automatic adjsutment takes place- this is not so with transistors (so with IGBTs). All you are looking for is a 32 to 40 KW 300 to 400 KHz power supply using MOSFETs- I suppose source is 3 phase AC mains at 440 V 3 phase 4 wire -I hope. Fullwave rectified, full bridge oscillator at 32 KHz can be designed without difficulty.

Nanu Karnatakado rajadhaniyally irutene. Nanage dooravani kare madi sone entu eradu mooru nalaku nalkku aaru mooru ombattu. mohanadivekar

Nanu Karnatakado rajadhaniyally irutene. Nanage dooravani kare madi sonne entu sonne eradu mooru mooru nalaku nalakku aaru mooru ombattu.

http://www.electro-tech-online.com/electronic-projects-design-ideas-reviews/24029-need-help-induction-cooker-heater.html

revealed by: http://www.bing.com/search?q=induction+heater+400kHz&src=IE-SearchBox&Form=IE8SRC

i don't have much experience in this field but
what i've studied is that the oscillators coils can develope currents exceeding in multiples that of the power source _{^{((the envisioned target is likely long (au) range transmitter (not induction heater) that's short resonator bar operates !likely at 615-680°C , has vibrating e¯-s (short dx all along the cross section) , main f (<>c/dx) and significanly lowwer higger f-s , there's some sort of signal transition near the antenna so it actually transmits other f than it resonates -- i don't comment this))}}

It appears to be good idea to develop IGBT inverter for industrial induction heating. It is known that new development in technology is patented in US ( US Patent No.US 5905646) for solid state high power pulse modulator.The modulator uses number of IGBT switches operating at relatively low voltage to replace high voltage thyratron switches. To the best my knowledge HF generators for High power industrial induction heating machines present manufacturers have not yet adopted this technology .400 KHz supply is required for skin hardening or brazing and relatively small components and do you really require so much high power as 50KW capacity. In India EMA Inda Kanpur, Microtech inductions pvt.Mumbai, Electrothrem Banglore and many others are manufacturing HF and MF Induction heating equipments.You can confirm from them weather they have started using this technology for their machines.The following link may be a good reading material on the subject.

http://mdk2001.web.cern.ch/mdk2001/Proceedings/Session23/Crewson.pdf

Contact Dr Jayant Baliga, inventior of IGBT at Univ of North Carolina

ELECTRONIC ENERGY CONVERSION
WITH A SWITCHED
SERIES-RESONANT NETWORK
OPERATING AT HIGH FREQUENCY
1986

may be worth to look

Do you want me to actually fabricate and supply a MOSFET based 40KW induction heating system to suit your needs- from Bangalore?I will need much more data and may be a visit to your shop. You are also welcome to Bangalore - to see where it will be fabricated. But you need to contact me first.