Control Techniques UD53, Руководство пользователя

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UD53 User Guide
Issue code: 53nu3
D-1
D Operation of a Resolver
A resolver is a rotating transformer that produces output voltages on a pair
of
SIN
and
COS
secondary windings. When an excitation voltage is applied
to the primary winding and the resolver shaft is rotated, amplitude-
modulated voltage waveforms appear on the secondary windings, where
the excitation voltage acts as a carrier for the modulation. In addition, on
each secondary, the phase of the carrier voltage is reversed twice every
revolution.
Figure D–1 shows the relationships between the resolver position and the
SIN
and
COS
outputs, as well as the phase reversals in the carrier waveforms for
forward rotation (for a clearer indication of the phase reversals, see
Figure D–2). The diagram also shows the waveform of the U motor phase
for a six-pole motor when the motor and resolver are aligned for zero phase
offset.
Resolver
position
SIN
secondary
COS
secondary
Carrier in phase
with excitation
Zero position
Carrier in phase
with excitation
Zero position
180
o
90
o
270
o
Carrier in anti-phase with excitation Carrier in phase with excitation
Carrier in anti-phase with excitation
Excitation
(primary)
Motor
U phase
Figure D–1 Sine and cosine modulation on the secondary windings