SMPS 2KW full bridge strange signal

Orcino · 25th July 2009, 04:45 PM

Hi, i made a SMPS full bridge with IGBTs IRGP4063 and a drive IR2113, but in test with 90vdc i look a strange signal in gate high side the IR2113 , this is a normal ? or is a noise ? look en teh sch below.

Very tahnks

zigzagflux · 25th July 2009, 05:11 PM

Sorry for the tangent; I'm not the one to ask about switching PS's.

Is that Orcad you are using? I miss that app

DCPreamp · 27th July 2009, 04:47 AM

Is that stepped waveform on the transformer primary, on the gate of the upper IGBT, or is it the signal IN to the hi-side driver?

If it's on the primary winding(s), then it's probably either dead-time where both switch devices are in a hi-z state, or it's because of a PWM signal <50% and represents a similar "off" period.

I've worked on DC/AC converters and seen the exact same stepped waveform. The supply worked perfect up into the KW range and the stepped waveform didn't seem to affect anything.

Is anything ringing, getting hot, or excess idle current? Is the supply able to make the desired output power?

Cool project! If you don't mind, keep us informed on your progress as there is a lot of interest in off-line switching supplies; me included.
Paul

TechGuy · 29th July 2009, 11:27 PM

I've had this problem before. It happens with the gate controller is not providing a gate voltage above the Drain\Collector input voltage. For your High side IGBT or MOSFET, the gate voltage must be at least 10 Volts higher than Drain\Collection voltage. Other wise it does fully turn on the transistor fully. Check to make your Gate driver's bootstrap is working properly. It likely cause by a bad connection or a faulty bootstrap diode, or you accidentially connected the boostrap diode backwards.

27th July 2009, 04:47 AM	#3
DCPreamp diyAudio Member Join Date: Jun 2005 Location: Sacramento, CA	Is that stepped waveform on the transformer primary, on the gate of the upper IGBT, or is it the signal IN to the hi-side driver? If it's on the primary winding(s), then it's probably either dead-time where both switch devices are in a hi-z state, or it's because of a PWM signal <50% and represents a similar "off" period. I've worked on DC/AC converters and seen the exact same stepped waveform. The supply worked perfect up into the KW range and the stepped waveform didn't seem to affect anything. Is anything ringing, getting hot, or excess idle current? Is the supply able to make the desired output power? Cool project! If you don't mind, keep us informed on your progress as there is a lot of interest in off-line switching supplies; me included. Paul __________________ "Believers cling to the myth despite the evidence, reinterpret the myth to suit the evidence, or lie about the evidence to support the myth." "To err is human; to blame errors on external factors is even more so."

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Offline full-bridge SMPS....need help	Nejc_car	Power Supplies	1165	6th January 2012 12:15 AM
Full Bridge 90A SMPS...	hawkfeather	Power Supplies	11	20th December 2005 07:59 AM
Whats the difference between full bridge and half-bridge SMPS ?	skaara	Class D	6	3rd February 2005 07:23 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

25th July 2009, 05:11 PM	#2
zigzagflux diyAudio Member Join Date: Oct 2006	Sorry for the tangent; I'm not the one to ask about switching PS's. Is that Orcad you are using? I miss that app

29th July 2009, 11:27 PM	#4
TechGuy diyAudio Member Join Date: Apr 2006 Location: Connecticut	I've had this problem before. It happens with the gate controller is not providing a gate voltage above the Drain\Collector input voltage. For your High side IGBT or MOSFET, the gate voltage must be at least 10 Volts higher than Drain\Collection voltage. Other wise it does fully turn on the transistor fully. Check to make your Gate driver's bootstrap is working properly. It likely cause by a bad connection or a faulty bootstrap diode, or you accidentially connected the boostrap diode backwards.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)