There are three basic motor control modes, VF (voltage/frequency), SVC (sensorless vector control) and FOC (field-oriented control). They can be applied to different motor types IM (induction motor), PM and IPM (permanent magnet motors) as well as SynRM (synchronous reluctancy motors) in open or closed loop operation. For closed loop operation, the drive needs an encoder PG (pulse generator).

The control modes differ in the ease of setup and control quality, and you should always use the one that provides just sufficient performance for the targeted application. The availability of each mode depends on the drive model.

• VF mode is the easiest mode. It provides a constant relationship between output voltage and frequency to keep the stator flux constant. VF curve parameters allow adapting the relationship to the required load characteristics. This mode is perfectly suited to variable torque applications, like water pumps and fans. It is also a good solution for constant torque applications with little complexity, like conveyor belts
• SVC based on VF adjusts the voltage automatically. It includes slip compensation and provides higher torque and speed precision, especially at low frequency. It requires a simple auto tuning to determine the motor’s equivalent schematic values and fits well to applications like positive displacement pumps
• FOC uses Clark-Parke transformation to control torque and flux individually. It has the highest torque and speed precision, but requires a more complex tuning procedure. The control performance makes it the perfect solution for demanding applications, like crane, lift, stone crusher and for precise torque or position control

Performance	Mode	Speed Range	Torque
	IM VF / IM VF PG / IM SVC	1:50	150% ≥ 3 Hz
	IM FOC sensorless	1:100	200% ≥ 0.5 Hz
	IM FOC PG	1:100	200% ≥ 0 Hz
	PM SVC	1:20	100% ≥ Fnom/20 Hz
	PM FOC sensorless	1:100	100% ≥ Fnom/50 Hz
	IPM FOC sensorless	1:100	150% ≥ 0 Hz
	PM FOC PG	1:1000	200% ≥ 0 Hz
	SynRM FOC sensorless (PMA)	1:100	200% ≥ 0 Hz