Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k
Copyright by BSH Hausgeräte GmbH
Page 16 of 181
There are different ways of measuring the rotor position and speed:
•
Sensor-controlled commutation
-
Hall or optical sensors are used to determine the position of the rotor. The
advantage of the sensor-controlled commutation is that it also works for
very low torques or when stationary.
•
Sensorless commutation
-
The countervoltage in the coils, analysed by the motor electronics, is
used to determine the position of the rotor. A minimum rotational speed is
required in order to analyse the countervoltage. For this reason, EC motors
are switched idle until the minimum rotational speed is reached.
New procedures allow precise control even below the minimum speed by using
targeted brief current pulses, which do not move the motor but are influenced by
the rotor’s magnetic field.