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Hello,
I am thinking to build an add on to my home made DC T I G welder to be able to weld aluminum. I have few questions if someone is willing to help.
Please note:
1- My current setup is basically a buzz box with SCR phase controle on the pri to adjust the output current. so my DC bus will vary. currently it will vary the output from about 5A to about 150A, If I build IGBT H-Bridge, does the variable bus voltage affect the IGBTs operation? I only think about using the IGBTs to generate the alternate square wave. any other idea is welcomed.
2- The IGBTs I am using are 1MBI300L-120. what is the best way to drive them with PIC? I know the PIC PWM outputs only 5V and the IGBTs that I use need about 15V so I have to use a gate driver. I read several article online including AN889 by microchip, the circuit looks to complicated for my need. I also read the datasheet for the driver that microchip uses and it doest show all the extra hardware that was used in the AN889? what is your thought? My thought is to use four pulse transformers to generate 15VAC then rectify them to DC then use these four isolated power sources to drive the IGBTs.
3- I only need to have frequency that adjustable from 5 to 200 Hz. what is the best configuration for my project for the PIC to drive the four IGBTs, full H-Bridge or half H-Bridge? I am thinking to use four IGBTs in half H-Bridge as the PIC I am thinking to use only support dead band control in the half bridge mode.
if there is simpler idea, please share it. I like it to be simple and effective.
Any input is greatly appreciated,
I am thinking to build an add on to my home made DC T I G welder to be able to weld aluminum. I have few questions if someone is willing to help.
Please note:
1- My current setup is basically a buzz box with SCR phase controle on the pri to adjust the output current. so my DC bus will vary. currently it will vary the output from about 5A to about 150A, If I build IGBT H-Bridge, does the variable bus voltage affect the IGBTs operation? I only think about using the IGBTs to generate the alternate square wave. any other idea is welcomed.
2- The IGBTs I am using are 1MBI300L-120. what is the best way to drive them with PIC? I know the PIC PWM outputs only 5V and the IGBTs that I use need about 15V so I have to use a gate driver. I read several article online including AN889 by microchip, the circuit looks to complicated for my need. I also read the datasheet for the driver that microchip uses and it doest show all the extra hardware that was used in the AN889? what is your thought? My thought is to use four pulse transformers to generate 15VAC then rectify them to DC then use these four isolated power sources to drive the IGBTs.
3- I only need to have frequency that adjustable from 5 to 200 Hz. what is the best configuration for my project for the PIC to drive the four IGBTs, full H-Bridge or half H-Bridge? I am thinking to use four IGBTs in half H-Bridge as the PIC I am thinking to use only support dead band control in the half bridge mode.
if there is simpler idea, please share it. I like it to be simple and effective.
Any input is greatly appreciated,
