Siemens CBP Manual Del Usuario página 109

SBR1/2 – Sensor Board Resolver (only for MASTERDRIVES Motion Control)
Function principle
8-2
The position of an exciter coil in the rotor in relation to two stator coils is
evaluated in the resolver.
A high-frequency carrier signal (5 to 10 kHz) is injected into the rotor
winding of the resolver via a rotary transformer. The high-frequency
current flowing in the rotor induces a high-frequency voltage into the
two stator coils arranged at right-angles to each other. The amplitude of
this voltage depends on the present position of the rotor winding or of
the rotor. The envelope curve of the voltage induced into the stator coils
is a sine or cosine curve.
On account of the right-angle arrangement of the stator coils, one coil
will supply the sine value, and the other coil the cosine value of the
present rotor position. Both signals are sensed via A/D transformers.
Subsequently, the unit software calculates the position angle α from
these two signals via trigonometry functions.
The change of the position angle α between two sampling times
provides the current speed of the motor.
U
Sine track
Sine pick-off
Rotor winding
Cosine pick-off
Fig. 8-2 Schematic diagram of a resolver
Excitation: 5 to 10 kHz
Rotary
U
Cosine
transformer
track
6SE7087-6NX84-0FF5
Option boards SIMOVERT MASTERDRIVES
06.2005
Siemens AG