Derek,
The maximum value of 5.1A for Rated Current RMS comes from the Maximum Phase Current value. The Maximum Phase Current needs to be the value of the motor phase current when the ADC reads 3.3V. For the reference hardware the Maximum Phase Current is 8A.
The relationship is that the Rated Current RMS cannot be larger than Maximum Phase Current / sqrt(2). This is to ensure that KMS doesn't attempt to control a current it can't actually read.
If you want to run with that larger current you need to be on your own hardware that can handle (and sense) the larger phase currents.
That being said, in PMSM (and BLDC) motors current is directly proportional to the torque. So even if your motor is rated for 37.5A, unless you are running in a situation where that amount of torque is required you can set this value to the maximum of 5.1A and KMS should be able to run your motor just fine.
KMS only uses the Rated Current RMS in order to establish how much current to use for the Self Commissioning and Inertia tests and to saturate the Speed loop output.
