Influence of a Winding Short-Circuit Fault on Demagnetization Risk and Local Magnetic Forces in V-Shaped Interior PMSM with Distributed and Concentrated Winding

Abstract

This paper presents a comparison of 30/8 and 12/8 AC permanent magnet motors with distributed (DW) and concentrated winding (CW) designed for electric vehicle traction. Both prototypes are based on an interior permanent magnet (IPM) motor topology and contain V-shape magnets. The radial flux AC IPM motors were designed for an 80 kW propulsion system to achieve 125 N·m. Finite element models (FEM) used to design the geometry of IPM motors and the required useful parameters of electric motors are widely investigated. The accuracy of finite element models is verified and validated on the basis of test data. Numerical simulations of healthy and faulty operation states, and studies of winding faults based on the FEM offer a deeper understanding of the associated phenomena. Therefore, in this paper, a short-circuit fault in a stator winding was simulated to investigate the transient currents under an external load collapse, for all winding phases. These simulations were used to define other important machine parameters to improve mechanical reliability of the motors and to assess the potential risk of permanent magnet (PM) demagnetization. Furthermore, the analysis of local magnetic forces affecting the PMs in the rotor and their possible displacement in a short-circuit situation were performed, also taking into account the centrifugal force. Lastly, it is demonstrated that the choice of winding configuration has a significant impact on the uncontrolled displacement of magnets in the rotor.

Archives of Electrical Engineering

“…During the test, the coolant system was not used, and in the FEA, the temperature was assumed to be 25 • C. To avoid a significant impact of the heat transfer on the torque production at varying loads and efficiencies of PM motors using NdFeB magnets, the measurements were performed quickly and at the same room temperature (25 • C). As it was measured in detail in [29], the measured peak cogging torque was 0.87 N•m and 1.25 N•m (the higher value applies to the CW IPM motor). At the same time, the obtained measurements were sufficiently convergent compared to the calculated values of the cogging torque for the DW and CW, and the difference was not greater than 2% and 16%, respectively.…”

“…As can be seen, the THD factor of the torque does not differ significantly between both machines, nevertheless, the shape of the deformation characteristics between the two machines differs significantly. A detailed analysis of the electromagnetic torque at sinusoidal current load operation is also shown in [29], where it was observed that a DW IPM motor has a higher torque constant and a lower torque ripple. Electromagnetic torque 𝑇 e is calculated using the virtual work method which is based on the stored magnetic co-energy change with a small displacement 𝜃. 𝑇 e equals the derivative of the magnetic co-energy 𝑊 co-eng with respect to the angular position at constant current, and is expressed as:…”

“…In addition, from an economic point of view, this configuration is most desirable and also a V-shape IPM motor has good performance in both torque and extended speed [27,28]. Presented IPM prototypes were widely investigated in relation to a winding short-circuit fault on demagnetization risk and local magnetic forces [29]. In this paper, the authors have decided to extend the study of the performance and thermal investigations in the proposed prototypes.…”

A Study on a Slotless Brushless DC Motor with Toroidal Winding

“…Processes 2021, 9, x FOR PEER REVIEW 2 of 19 techniques for applying chambers and notches, eccentricities, and skews to the stator or rotor core [1][2][3][4]. Second, the combination of the number of poles, number of slots, and the winding pattern have changed [5][6][7]. Finally, there is a technology that reduces the vibration and noise in the motor by adding harmonic components to the current in the controller [8][9][10].…”

Design and Control of a Permanent Magnet Assisted Synchronous Reluctance Motor

“…Many studies have been carried out in the field of designing PMa-SynRM rotors, where it is possible to improve the output torque and the power factor by increasing d-q axis inductance difference (𝐿 𝑑 − 𝐿 𝑞 ) and the saliency ratio (𝐿 𝑑 /𝐿 𝑞 ) [27]. In this kind of motors, the most frequent configurations of the stator windings are distributed and concentrated slots windings [28,29]. Also, single-and double-layer windings focused to reduce harmonics [30].…”