The Modeling and Investigation of Slot Skews and Supply Imbalance on the Development of Principal Slotting Harmonics in Squirrel Cage Induction Machines

Abstract

A discrete winding function analysis (DWFA) based approach for the modelling of skewed rotor cage-type induction motor with minimal simulation time is presented in this paper. The rotor slot skew has a significant attenuating impact on principal slotting harmonics (PSH) or rotor slotting harmonics (RSH). These harmonics can play a significant role in sensor-less speed estimation and condition monitoring of induction machines. The advanced fault diagnostic algorithms are becoming increasingly dependent on the fast and accurate mathematical models of electrical machines. The most accurate models are based on the finite element method (FEM), but the computational complexity and the required simulation time make them unsuitable for model-dependent fault diagnostic algorithms. Moreover, as most models are 2D, they cannot incorporate axial asymmetries such as rotor slot skews. Furthermore, most analytical models, such as modified winding function analysis (MWFA), depend upon the continuous integration functions, increasing complexity while implementing them in the online environment in digital signal processing boards. To resolve all those issues, DWFA based model is proposed in this paper, which can simulate the majority of the faults in negligible time compared to the corresponding FEM models. The impact of slot skews and unbalanced power supply on the current spatial harmonics is studied, and the results are compared with the practical measurements taken from the laboratory setup.

Improved air gap permeance modelling for single-slice magnetic equivalent circuits of skewed induction motors

“…The proposed skew method Improved air gap permeance modelling exhibits the desired torque ripple reduction (Kawase et al, 2009). As rotor skew increases, the length and the resistance of the rotor bars increase, which reduces the average torque at the rated slip to a minor extent as observed (Darjazini et al, 2021;Asad et al, 2021). In contrast, Kawase et al (2009) observed an optimum of the average torque for a skew of one rotor slot pitch.…”

Computationally Efficient Reduced Order Modeling of DFIG-Based Wind Turbines: A Novel Frequency-Weighted and Limited Model Reduction Approach With Error Bounds

“…Their versatility, manageability, remarkable energy efficiency, better power quality, and other outstanding qualities lead to their extensive use [6]. The addition of reactive power compensators enhances the complexity of wind energy conversion systems, which include double cage induction machines (DCIMs) and single cage induction machines (SCIMs) [7], [8]. When using a SCIM with two squirrel cages instead of one with one cage, the order and complexity increase exponentially.…”

Modified magnetic equivalent circuit model for magnetic field analysis of one cage‐rotor induction motor used in electric submersible pumps

“…The main property of MEC model is to consider the magnetic saturation in iron parts. Other analytical techniques such as winding function theory [2], sub‐domain model [3], conformal mapping (CM) method [4], and field reconstruction method [5] cannot consider the magnetic saturation.…”