You should size your motor based on the load torque-speed profile. And, as stated, use an inverter rated motor as to insulation. In the US, that would mean a motor rated to MG1 Part 31, in my opinion.
You must also consider cooling issues if the motor is to be operated loaded below about 1/3 speed. You may have to switch to an auxiliary-cooled motor if you are operating heavy loads at slower speeds. Your motor manufacturer can give you speed-load profiles for your motor.
Finally, given the motor's continuous current at the expected continuous load plus the motor's peak current at the load's peak torque requirement, check your drive to be sure you have enough ampacity both continuous and short-term peak to cover the motor's requirements. If the drive has more, you are ok. If the drive has less, the drive is not big enough for the job. If the drive has exactly what your motor needs, why then, you are having an incredibly lucky day!