Calculate flux partial derivatives for FEM-Parameterized PMSM block

```
[dFdA,dFdB,dFdC,dFdX]
= elec_calculateFluxPartialDerivatives(A,B,C,X,F)
```

```
[dFdA,dFdB,dFdC,dFdX,D,Q]
= elec_calculateFluxPartialDerivatives(A,B,C,X,F)
```

`[`

calculates the partial derivatives from flux linkage. For improved numerical
performance, the FEM-Parameterized PMSM block works with flux linkage
partial derivatives, rather than directly with flux linkage. If your finite-element
motor design tool does not have an option to output partial derivatives, then you
can use this function to calculate the partial derivatives from the flux linkage.
The flux linkage `dFdA`

,`dFdB`

,`dFdC`

,`dFdX`

]
= elec_calculateFluxPartialDerivatives(`A`

,`B`

,`C`

,`X`

,`F`

)`F`

must be a four-dimensional matrix with the
first three dimensions corresponding to the `A`

,
`B`

, and `C`

phase currents, and the
fourth dimension corresponding to the rotor angle `X`

. The
function returns four-dimensional matrices for the four partial derivatives. Use
this syntax in conjunction with the 4-D Data variant of the block.

`[`

returns
two additional output arguments corresponding to `dFdA`

,`dFdB`

,`dFdC`

,`dFdX`

,`D`

,`Q`

]
= elec_calculateFluxPartialDerivatives(`A`

,`B`

,`C`

,`X`

,`F`

)* d*-axis
and

`q`

`d`

`q`

The function calculates partial derivatives using Akima splines,
the same method that is used for `smooth`

interpolation
in the Simscape™ language `tablelookup`

function.
For more information, see Smooth Interpolation Algorithm (Simscape). Akima splines are
suitable for estimating partial derivatives due to their smooth nature
and tendency not to introduce local gradient reversals.