zombiess
10 MW
Ok, I think I get it now. Phase A only 3 of the 6 FETs are driven by PWM while 3 in Phases B and C are either floating or grounded depending on the commutation.
Let's talk theory, ignore losses for now and hope I have the cycle right (you should get what I'm after though)
So say phase A is driven high, phase B is floating and phase C is grounded, Phase A has 3 FET's in parallel with a total of 3mOhm (9mohm each), phase C is providing the ground which also had 3 FETs in parallel with a RDSon of 3 mOhm. If our supply voltage is 100V we now have 100V passing through Phase A, 6 FETs with a sum of 6mOhm combined from the high and low side. So are we only dissipating power in the high side 3 FETs at 3mOhm or in all 6 equally at 6 mOhm?
Let's talk theory, ignore losses for now and hope I have the cycle right (you should get what I'm after though)
So say phase A is driven high, phase B is floating and phase C is grounded, Phase A has 3 FET's in parallel with a total of 3mOhm (9mohm each), phase C is providing the ground which also had 3 FETs in parallel with a RDSon of 3 mOhm. If our supply voltage is 100V we now have 100V passing through Phase A, 6 FETs with a sum of 6mOhm combined from the high and low side. So are we only dissipating power in the high side 3 FETs at 3mOhm or in all 6 equally at 6 mOhm?