However, the inverse problem of obtaining these parameters
from a known TSC is not so simple, because it is a transcendent
equation, with multiple roots, and ill-conditioned for some parameters.
In [3], it is proposed a modified equivalent circuit that
can be determined from the TSC peak torque, the frequency at
which peak torque occurs, and the voltage induced in one phase
of the winding at the peak frequency. Recently, the uniqueness
of the TSC was proved, and a method was presented [4] to interpolate
the curve, given three arbitrary points at asynchronous
speeds (from now on, the Nelatury method). This is a timely
contribution, particularly in the wind generation field, considering
current efforts in introducing direct torque measurements
in the control of such systems. In [5], a method based on the use
of a contactless magnetostrictive sensor and a robust observer
is applied for the shaft torque measurement of turbogenerators.
The Nelatury method gives a guide for translating similar measurement
schemes to the induction machine.