HighHopes
10 kW
- Joined
- Mar 28, 2013
- Messages
- 929
ahhhh..... github. i been avoiding you for years cause i tend not to work in teams so i do all my revision control myself. but ya, i can see its usefulness.
lets say i wanted to make a change to the schematic you posted in github. you ok if i do that? i don't know how to do this yet in github.. will need to watch some tutorials or something i guess. but, as of this moment, here's how i see it. lets say i downloaded your entire zip folder. then i open my kicad, and decide to make a change. i do that, save it. zip entirety of the folder then upload to github (following tutorial methods so repository will do revision history properly). that sounds something close to the correct method?
anyway.. haven't read enough about the AMC1303 chip yet but i was thinking the schematic you have is shunt resistance referenced to ISOGND (V- is connected to ISOGND). this would be for like measuring the current in IGBT emitter to ground path which is not what we want. we want to measure the phase current in the AC output which is not really referenced to anything, its truly differential (or should be) because this shunt is in the inverter AC output. easy enough... just don't connect ISOGND to V-. but the chip has a power supply which is referenced to ISOGND so now you have a floating measurement (which really is differential) which is good but can the chip do that? or does it have to have V- connected to ISOGND to achieve the datasheet performance. that's what i was thinking when i open your schematic and did first browse through. otherwise, looks good. and i like the voltage divider at the buffer output... gives you some interface option to different voltage level in a pinch. for me, i'll be using a DSP with 3.3V analog in.
also, there's bound to be some voltage transients on the shunt. reading AMC1303 datasheet makes me think it self protects but need to confirm by reading more.
lets say i wanted to make a change to the schematic you posted in github. you ok if i do that? i don't know how to do this yet in github.. will need to watch some tutorials or something i guess. but, as of this moment, here's how i see it. lets say i downloaded your entire zip folder. then i open my kicad, and decide to make a change. i do that, save it. zip entirety of the folder then upload to github (following tutorial methods so repository will do revision history properly). that sounds something close to the correct method?
anyway.. haven't read enough about the AMC1303 chip yet but i was thinking the schematic you have is shunt resistance referenced to ISOGND (V- is connected to ISOGND). this would be for like measuring the current in IGBT emitter to ground path which is not what we want. we want to measure the phase current in the AC output which is not really referenced to anything, its truly differential (or should be) because this shunt is in the inverter AC output. easy enough... just don't connect ISOGND to V-. but the chip has a power supply which is referenced to ISOGND so now you have a floating measurement (which really is differential) which is good but can the chip do that? or does it have to have V- connected to ISOGND to achieve the datasheet performance. that's what i was thinking when i open your schematic and did first browse through. otherwise, looks good. and i like the voltage divider at the buffer output... gives you some interface option to different voltage level in a pinch. for me, i'll be using a DSP with 3.3V analog in.
also, there's bound to be some voltage transients on the shunt. reading AMC1303 datasheet makes me think it self protects but need to confirm by reading more.