I am still a newbie at this, please be patient.
I am working on a Request For Proposal for one of our major customers.
The customer is specifying the use of an incremental quadrature encoder to sense the motor speed.
I'm hoping that the FOC approach would eliminate the need for the encoder, however I am not sure because this statement in the customer specification-
"The controller shall provide current for 5 s duration at electrical frequency less than 1 Hz (including stall). If the respective motor does not accelerate above 1 Hz (electrical) within this time, the controller may apply lesser current (including zero at the corresponding 3-phase outputs) for up to 1 s before resuming function.
The idea behind this requirement is to allow for full rated current even at stall with provisions for cool-down of the junction temperatures shortly after."
Known design specifics:
Maximum fundamental frequency in which current control is required is 400 Hz.
The controller will be switching frequency between 20k- 30k Hz.
Specific motor characteristics are not available at this time.
Typical motor speed is ~5,000 rpm, with phase current ranging from 5Arms to 80Arms.
DC Link voltage ranges from 32Vdc to 60Vdc
My questions are:
Is this a good application for using the sensorless FOC?
If so, are there any recommendations as to how to convince the customer this is the best approach (other than the obvious cost savings)?
Thank You,
Mark
