43
Inductance (mH)
Inductance (mH)
Modeling of Electric Machines Using Winding Function
0.1
0
–0.1 0
1
2 3 4 5 Rotor Position (Mechanical Radian)
6
0
1
2 3 4 5 Rotor Position (Mechanical Radian)
6
0.1 0 –0.1
FIGURE 3.11 Mutual inductance of stator a phase to one rotor loop of a healthy RSM using MWFA (top) and FE (bottom). (From P. Neti, “Stator Fault Analysis of Synchronous Machines,” PhD dissertation, University of Victoria, December 2007. With permission.)
Figure 3.11 presents the inductance profile of a synchronous reluctance machine using MWFA with comparative FE generated inductance profile. Figure 3.12 shows a similar comparison of inductance profiles of a standard synchronous machine (SM). These results clearly demonstrate the power of WFA/MWFA where inductance profiles could be computed at much higher resolution but at a fraction of time required for FE methods and without sacrificing much accuracy. It is shown by Ilamparithi and Nandi that a commercial FE simulation package could take around 50 hours to simulate 1.5 seconds of steadystate run of a 3 hp, 44 rotor bar induction motor compared to 4 minutes of running time for a MWFA-based coupled-inductive circuit MATLAB code while generating similar spectral characteristics [10]. Table 3.1 provides the detailed results.