Hello!
I am developing a 60 VDC powered 3 phase motor driver with 17 ARMS phase current (for BLDC and BLAC motors basically)
I was wondering which is the main factor used to choose the DC bus capacitor? In AC powered drives, the bus capacitor is chosen according to the allowed bus voltage ripple. Since the device will be powered from DC power supplies or batteries (depending on the application) I don't know which are the key parameters to make the choice.
Previous designs used:
2x
100 µF 100 VDC Aluminum Electrolytic SMD caps with 330 mΩ ESR and 450 mARMS current ripple capacity
... and they get very hot, actually it was the hottest element in the power stage!
Right now I am using
2x
150 µF 100 VDC Electrolytic Low ESR (100 mΩ) , Low ESL TH caps.
These seem to work better.
Power efficiency, electromagnetic compatibility and size are important in the design...
Thank you in advance for your responses and comments!
Ernest