Virtual encoder replaces real encoder
In order to be able to benefit from the advantages of field-oriented control even in price sensitive applications, Nanotec has developed a sensorless control for stepper motors that uses a virtual encoder in the controller to determine the position and speed of the rotor. In this way the stepper motor operates as a servo motor – without step losses, without resonances and without the risk of overheating.
In Nanotec’s sensorless system, an auto setup routine measures the connected motor and automatically determines all the required parameters. Depending on the motor type, the speed and positioning information is obtained at a lower speed of between 25 and 250 rpm with an accuracy comparable to that of an optical encoder with 500 or 1000 increments. Therefore the level of control that is achieved is the same as that of a motor controlled by means of an encoder. For lower speeds and positioning purposes it is possible to switch automatically to open-loop mode.
With the help of this technology motors may be run in closed-loop mode when the classic closed loop control with encoder cannot be used due to cost constraints.