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1,44
1,42
1,40
1,38
1,36
1,34
1,32
1,30
1,28
1,26
-50
a = 1.305, b = 6.55E-4°C
Figure 5-3 Example Polynomial Fit Procedure.
•
Derive the coefficients of the application sensitivity polynomial from the parameters a, b, and c obtained from
the quadratic fit using
b
----------------------------------------- -
TC
=
1
a
b T
+
----------------------------------------- -
TC
=
2
a
b T
+
5.4
Calculation of Final Temperature Compensation Parameters
After determination of the application sensitivity polynomial S
compensation paramters TL and TQ in the EEPROM such that the overall sensitivity of the TLE4997 shows the
desired increase over temperature to compensate for the thermal reduction of the magnet's remanence in the
application.
5.4.1
Algorithm for Finding the Optimum Temperature Coefficient Set
For an optimum temperature compensation in the application, the set of coefficients TL and TQ have to be found
that best fulfill the condition stated in
in that is minimized in an iterative procedure.
S
DSPfinal
ε T
(
)
--------------------------------------------------------------- - 1
=
J
⋅
C S
DSPpre
S
(T
) is the integrated temperature polynomial given by the combination of
DSPfinal
J
Equation
(5.2), with the final parameters TL
with the pre-configured parameters TL
User's Manual
y = 2,135E-06x
0
-1
, c = 2.135E-6°C
Equation (5.8)
and
Equation
⋅ ⋅
2 c T
+
0
2
⋅
⋅
c T
+
0
0
c
2
⋅
⋅
c T
+
0
0
Equation
(
)
T
J
–
(
) S
⋅
(
)
T
T
J
app
J
final
and TQ
pre
Calibration of TLE4997 Temperature Compensation
2
+ 6,550E-04x + 1,305E+00
50
T
(°C)
J
-2
(5.9).
, it is necessary to adapt the temperature
app
(5.6). To find this parameter set, an error function ε(T) is defined
and TQ
. S
(T
) is the integrated temperature polynomial
final
DSPpre
J
. C is a constant to be varied in the iterative procedure.
pre
28
TLE4997
User's Manual
S(i)
Quadratic fit
100
150
Equation (5.1)
v01_01, 2019-08
(5.8)
(5.9)
(5.10)
and
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