Nanotec Electronic, based near Munich in Feldkirchen, Germany, has developed a sensorless control specifically for BLDC motors. This control is designed to determine the position of the rotor indirectly from the behavior of the current control rather than measuring its position directly with an encoder.
The control from Nanotec is designed to be easy to adjust using a few standard parameters (resistance, inductance, magnetic flux). Additionally, because the device is insensitive to parameter fluctuations, control quality is not affected by production tolerances or ambient temperature.
The sensorless control can be used within a speed range extending from 100,000 RPM down to approximately 3% of the nominal motor speed - even with a direction reversal.
The resolution is similar to that of an encoder with 1,024 increments, enabling sine commutation of the motor. Speed fluctuations, such as those that occur due to tolerances in the angles between the hall sensors or the concentricity error of an encoder, are eliminated since this method only measures electrical values.
Because the unit does not contain sensor hardware, drive systems can be assembled with a lighter and more compact design, while also requiring fewer connection cables and plug-in contacts.The sensorless control is offered as a plug-in board for integration in device solutions or for use as a standalone motor controller. A wide spectrum of control equipment is available, ranging from speed control and analog or digital inputs to complex field-bus controlled applications.
For example, an application for the sensorless control is the slotless BLDC motors from the Nanotec DS28 series. Due to their low inductance and the rapid current rise in the windings, they are built to maintain high speeds without problems. In the DS28 there is no cogging torque, so these motors run smoothly even at low speeds. Because the slotless BLDC motors do not exhibit iron loss, they are designed to have a higher efficiency than conventional BLDC motors.
Other possible applications include high-speed BLDC motors without hall sensors, as found in dental drills, CNC milling spindles and manual tools, and medical pumps or motors for respiratory therapy.
For more information contact:
Stephan Huber, CEO
Nanotec Electronic, U.S. Inc.
38 Montvale Avenue, Suite 255 C15
Stoneham, MA 02180
781-219-3343
info@us.nanotec.com
www.us.nanotec.com