All this is very interesting and very enlightening .
I can see , if the need is to break the 3,600 rpm barrier , it would be useful .
If you have a DC source , to begin with , like PV or wind energy , it could be very useful .
But , I think I am missing something ? For the mini splits , at least ( if you do not scale it up for the bigger HVAC systems ) the input is 1 phase AC . Either 120 or 240 ( possibly 208 VAC ) . It is quite doable to build a 1 phase " traditional " VFD . And use a " traditional " 3 phase AC motor .
For a HVAC compressor , I do not see the need to break the 3,600 rpm barrier ?
So , what is the need to use the brushless DC , instead of the 3 phase AC motor ?
Less circuitry / cost in the electronics ? Greater energy efficiency in the whole system ?
As a side note , I am guessing both the electronics for the BLDC motor and a " traditional " VFD would require filtering / shielding to prevent unwanted " electrical noise " from being impressed back on the AC power source ?
Thanks , :-)
Wyr
God bless
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