A virtual instrument for frequency analysis of electrical machines

This paper presents a virtual instrument (VI) to carry out the frequency response test and parameter estimation. The VI was used for parameter estimation of induction, synchronous and direct current machines. The constrained least square algorithm was used for the parameter estimation of the linear machine models. In each machine test, a variable frequency alternating current was applied through the machine terminals while it was at the standstill condition. The obtained voltage and current responses were used to calculate the magnitude and the phase angle of the relevant transfer function. The frequency domain response was measured from 1 mHz through 1 kHz. The VI was implemented in the programming environment of LabVIEW. It can generate the excitation signal, acquire the necessary signals, process the signals for frequency response and carry out the parameter estimation