Investigation of equivalent stator-winding thermal resistance during insulation system ageing

Williamson, S. J.; Wróbel, Rafał; Yon, Jason; Booker, Julian D; Mellor, P.H.

doi:10.1109/demped.2017.8062409

Cited by 11 publications

(5 citation statements)

References 21 publications

(19 reference statements)

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“…The LPTN tuning procedure was performed with the PMSM unaged, that is as conventionally done in 'traditional' EMs thermal modelling. Nonetheless, insulation thermal aging can also influence the heat transfer within the machine windings [26], since the insulation physical properties are modified. Thus, future work will also address this aspect which is omitted here as it goes beyond the scope of the paper.…”

Section: A Lumped Parameter Thermal Networkmentioning

confidence: 99%

Thermal Overload and Insulation Aging of Short Duty Cycle, Aerospace Motors

Madonna

Giangrande

Lusuardi

et al. 2020

IEEE Trans. Ind. Electron.

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Electrical machines for transportation applications need to be highly reliable, particularly if they drive safety-critical systems. At the same time, another main requirement is represented by the significant torque density, especially for aerospace, where weight constraints are extremely stringent. For achieving high peak torque, an effective strategy consists in supplying the windings with a current greater than the rated value; thus, thermally overloading the machine for limited time periods. However, if the insulation is overheated, the machine lifetime is shortened and reliability issues can arise. This paper experimentally investigates the influence of short-time thermal overload on the insulation lifetime for low voltage, random wound electrical machines. The analysis is performed on round enamelled magnet wire coils, which are aged by accelerated thermal cycles. The obtained results are statistically processed through a two parameter Weibull distribution. According to the findings of the experimental data post-processing, a lifetime prediction model is built. This model is employed for predicting the lifetime consumption of a motor embedded into an electromechanical actuator for aerospace application.

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Section: A Lumped Parameter Thermal Networkmentioning

confidence: 99%

Thermal Overload and Insulation Aging of Short Duty Cycle, Aerospace Motors

Madonna

Giangrande

Lusuardi

et al. 2020

IEEE Trans. Ind. Electron.

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“…In fact, although the thermal degradation of the EM insulation is widely addressed in literature [20], its link to the EM thermal modelling is usually omitted, particularly for impregnated, random wound EMs (which represent the most common winding arrangement in low voltage EMs). An exception is represented by [21], where an investigation on Litz-type winding is carried out. The main outcome of [21] indicates a strong correlation between insulation thermal aging and equivalent thermal resistance for the particular case of Litz-wire winding topology.…”

Section: Introductionmentioning

confidence: 99%

“…An exception is represented by [21], where an investigation on Litz-type winding is carried out. The main outcome of [21] indicates a strong correlation between insulation thermal aging and equivalent thermal resistance for the particular case of Litz-wire winding topology.…”

Section: Introductionmentioning

confidence: 99%

Influence of Insulation Thermal Aging on the Temperature Assessment in Electrical Machines

Madonna

Giangrande

Galea

2021

IEEE Trans. Energy Convers.

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Thermal modeling and temperature assessment of electrical machines often rely on the use of lumped-parameter thermal networks. A historic limitation of analytical thermal models is their need for an experimental fine-tuning, necessary for selecting the appropriate values of thermal conductivity and convection heat transfer coefficients. This evaluation procedure is commonly carried out at the design stage of a new machine, by assuming that its thermal behavior will remain unchanged throughout its whole lifetime. This paper demonstrates, through an in-depth experimental investigation, how the capability of heat extraction from a machine's hot spot towards the coolant can be strongly affected by the level of thermal aging of its insulation system. Based on the experimental findings, a decrement of the winding equivalent thermal conductivity is noted as the thermal aging accumulates, with a corresponding progressive increment in hot-spot temperature.

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“…Damage to the insulation can be caused by a flow of current with an intensity exceeding rated values, which leads to release of energy in a form of heat as well as by a mechanical stress. In addition, ubiquitously used frequency converters 2 of 17 such as inverters that use fast switching PWM also affect faster degradation of the insulation [16,17]. The assessment of the state of the insulation takes place by means of various dielectric measurements such as that of the dissipation factor, capacitance, or insulation resistance [18].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Torque Ripples of an Induction Motor Taking into Account a Inter-Turn Short-Circuit in a Stator Winding

Pietrowski

Górny

2020

Energies

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Despite the increasing popularity of permanent magnet synchronous machines, induction motors (IM) are still the most frequently used electrical machines in commercial applications. Ensuring a failure-free operation of IM motivates research aimed at the development of effective methods of monitoring and diagnostic of electrical machines. The presented paper deals with diagnostics of an IM with failure of an inter-turn short-circuit in a stator winding. As this type of failure commonly does not lead immediately to exclusion of a drive system, an early stage diagnosis of inter-turn short-circuit enables preventive maintenance and reduce the costs of a whole drive system failure. In the proposed approach, the early diagnostics of IM with the inter-turn short-circuit is based on the analysis of an electromagnetic torque waveform. The research is based on an elaborated numerical field–circuit model of IM. In the presented model, the inter-turn short-circuit in the selected winding has been accounted for. As the short-circuit between the turns can occur in different locations in coils of winding, computations were carried out for various quantity of shorted turns in the winding. The performed analysis of impact of inter-turn short-circuit on torque waveforms allowed to find the correlation between the quantity of shorted turns and torque ripple level. This correlation can be used as input into the first layer of an artificial neural network in early and noninvasive diagnostics of drive systems.

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Investigation of equivalent stator-winding thermal resistance during insulation system ageing

Cited by 11 publications

References 21 publications

Thermal Overload and Insulation Aging of Short Duty Cycle, Aerospace Motors

Thermal Overload and Insulation Aging of Short Duty Cycle, Aerospace Motors

Influence of Insulation Thermal Aging on the Temperature Assessment in Electrical Machines

Analysis of Torque Ripples of an Induction Motor Taking into Account a Inter-Turn Short-Circuit in a Stator Winding

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