I was asking myself the other day ‘what does the KV rating mean when using an odrive?’ because normaly this is the rpm/V, but with an Odrive you chose the rpm yourself, so I thought maybe this is the maximum rpm you can chose, but according to my knowledge this is frequency related.
Your spot on in that the KV of the motor determines the maximum RPM you can choose.
kV is a physical property of the motor. A higher Kv will mean that a smaller voltage is induced in the stator windings by the rotor when you spin the motor than for an equivalent lower Kv motor. The KV rating of a motor is just as important for odrive as for any other motor controller as it determines the maximum speed that the motor can rotate for a given supply voltage while also being a good indicator of the motor torque produced for a given current. See this post for the KV to motor torque relationship.