TMS320F240 DSP Solution for Obtaining Resolver Angular Position and Speed (Rev. A)
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This
application
report
first presents
a TMS320F240
DSP
solution
and then
another
unique
approach
using
PGA411Q1
for obtaining
the angular
position
and speed
of a resolver.
A resolver
is an absolute
mechanical
position
sensor
used,
for example,
in servo
applications.
It is
basically
a rotating
transformer.
The sinusoidal
input
reference
is amplitude
modulated
with the sine and
cosine
of the mechanical
angle,
respectively.
These
two output
signals
have
to be decoded
to obtain
the
angular
position.
For decoding
the resolver
output
signals,
a basic
method
is introduced.
It uses
undersampling
and an
inverse
tangent
function.
To achieve
a higher
angular
resolution
an improved
method,
which
adds
oversampling
techniques
is used.
Due to an integral
invariant
filter,
which
is a combination
of an IIR and
FIR filter,
the digitized
angular
position
does
not suffer
any velocity
lag.
