Experimentally Calibrated Thermal Stator Modeling of AC Machines for Short-Duty Transient Operation

Godbehere, Jonathan; Wróbel, Rafał; Drury, David; Mellor, P.H.

doi:10.1109/tia.2017.2686328

Cited by 19 publications

(11 citation statements)

References 32 publications

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“…For instance, the computation of the thermal resistance between stator copper and stator core has to consider a heat path through an agglomerate of multiple materials with different thermal properties, while the thermal resistance between machine housing and the ambient areas comprises both convection and radiation phenomena. The literature reports dc tests that allow the calibration of such parameters [8,10,24,32]. It is interesting to observe that, even though for most of the applications those dc tests represent 'ad hoc' calibrating procedures, for the electric machine analyzed in this paper such supply conditions were also representative of the real machine operations.…”

Section: Lumped-parameters Thermal Models For Pm Synchronous Machinesmentioning

confidence: 98%

“…Sometimes, experimental component modeling on motorette samples is also used to calibrate analytical and numerical electric machine models [3,[8][9][10][11]. This approach unquestionably allows the modeling accuracy to increase, but time and budget for sample realization have to be properly considered.…”

Section: Lumped-parameters Thermal Models For Pm Synchronous Machinesmentioning

confidence: 99%

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Lumped-Parameters Thermal Network of PM Synchronous Machines for Automotive Brake-by-Wire Systems

Graffeo

Vaschetto

Miotto³

et al. 2021

Energies

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Thermal analysis represents a key factor in electrical machine design due to the impact of temperature increase on insulation lifetime. In this context, there has been a wide investigation on thermal modeling, particularly for machines used in harsh working conditions. In this perspective, brake-by-wire (BBW) systems represent one of the most challenging applications for electrical machines used for automotive smart actuators. Indeed, electro-actuated braking systems are required to repeatedly operate the electric machine in high overload conditions in order to limit the actuator response time, as well as to enhance gravimetric and volumetric specific performance indexes. Moreover, BBW systems often impose unconventional supply conditions to the electric machine, consisting of dc currents in three-phase windings to keep the rotor fixed during the braking intervals. However, a dc supply leads to uneven temperature distributions in the machine, and simplified thermal models may not accurately represent the temperature variations for the different machine parts. Considering such unconventional supply conditions, this paper initially investigates the applicability of a conventional lumped-parameters thermal network (LPTN) based on symmetry assumptions for the heat paths and suitable for surface-mounted PM synchronous machines used in BBW systems. An extensive test campaign consisting of pulses and load cycle tests representative of the real machine operations was conducted on a prototype equipped with several temperature sensors. The comparison between measurements and predicted average temperatures, together with insights on the unbalanced heat distribution under the dc supply obtained by means of finite element analyses (FEA), paved the way for the proposal of a phase-split LPTN with optimized parameters. The paper also includes a critical analysis of the optimized parameters, proposing a simplified, phase-split lumped-parameters thermal model suitable to predict the temperature variations in the different machine parts for PM synchronous electric machines used in BBW systems.

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Section: Lumped-parameters Thermal Models For Pm Synchronous Machinesmentioning

confidence: 98%

Section: Lumped-parameters Thermal Models For Pm Synchronous Machinesmentioning

confidence: 99%

Lumped-Parameters Thermal Network of PM Synchronous Machines for Automotive Brake-by-Wire Systems

Graffeo

Vaschetto

Miotto³

et al. 2021

Energies

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“…To reduce the level of uncertainty in the estimation of the LPTN parameters, some calibration methods have been developed. By using a particle swarm optimization routine, the thermal conductivity of stator winding in an AC machine is calibrated based on the experimental data from thermal tests performed on a stator-winding motorette in [27]. With the help of Matlab SIMSCAPE and Simulink Design Optimization, the critical convection coefficients in a water-cooled electrical machine are tuned on the basis of the tests on a stator sector in [28].…”

Section: Thermal Model Approach To Multisectormentioning

confidence: 99%

“…Step 1: The critical parameters are identified and their initial value is set to be within suitable ranges as suggested by the available literature [22]- [27]. Once this stage is completed, the LPTN is preliminary weighted with the first generation of critical parameters.…”

Section: Fine-tuning Of the Critical Parametersmentioning

confidence: 99%

Thermal Model Approach to Multisector Three-Phase Electrical Machines

Zhang

Giangrande

Sala

et al. 2021

IEEE Trans. Ind. Electron.

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Multisector machines reveal a high fault-tolerant capability, since failure events can be isolated by de-energizing the faulty sector while the healthy ones contribute in delivering the required power. This paper is focused on the thermal analysis of multisector three-phase machines in healthy and faulty operations. Firstly, a 3D lumped parameter thermal network (LPTN) of a single sector is developed and fine-tuned against experimental data, through a genetic algorithm for identifying the uncertain parameters. According to the operating conditions, the varying housing surface temperature affects the heat exchanged to the ambient. Hence, an analytical formula is proposed to adjust the natural convection coefficient value depending on the operating condition. Then, the 3D-LPTN, modeling the whole machine, is built aiming at investigating the thermal behavior during faulty conditions. Finally, the complete 3D-LPTN is employed for predicting the machine thermal performance under several faulty conditions. Furthermore, the current overload experienced by the healthy sector (in order to keep the same torque level as during the pre-fault operation) is determined, in accordance with the magnet wire thermal class. The effectiveness of the 3D-LPTN in predicting the temperature is experimentally demonstrated.

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“…The other method of promoting the accuracy of LPTN is calibrating thermal coefficients, which mainly include the free and the forced convection coefficients. J. Godbehereet et al identified the heat transfer coefficients of end-winding for an induction motor by experiments [15]. Y. Gai et al calibrated the forced convection coefficients of a traction motor, in which the results give a better understanding of the rotating effect on the flow [16].…”

Section: Thermal Resistance Between Winding and Tooth R T-cp Thermal mentioning

confidence: 99%

Improving Thermal Analysis Accuracy of LPTN for Vehicle Claw-Pole Alternator by Calibrating Forced Convection Coefficients Based on Experimental Results

Zhang

2019

IEEE Access

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Claw-pole alternators are particularly important for vehicle power generation due to their low cost, simple design, and mechanical robustness. High and low temperatures around vehicle claw-pole alternators (VCPAs) change their internal temperature distributions, thus thermal analysis is required for designing VCPAs. Aiming at improving the accuracy of evaluating the temperature of VCPAs, a novel lumped parameter thermal network (LPTN) is proposed to analyze the steady-state temperature of a double excitation VCPA under various ambient temperatures. The forced convection coefficients are calibrated in order that the LPTN can simulate the real heat transfer of the VCPA. The nonlinear least square method is applied to obtain the calibrated coefficients within a range of the tested ambient temperatures. Moreover, the effectiveness of the proposed method is verified via simulation studies, whereby the results show that the proposed LPTN with calibrated convection coefficients can accurately evaluate the temperature of VCPAs. Finally, these results soundly supply the technical knowledge for the thermal analysis and facilitate selecting the optimal scheme for machine designers.

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Experimentally Calibrated Thermal Stator Modeling of AC Machines for Short-Duty Transient Operation

Cited by 19 publications

References 32 publications

Lumped-Parameters Thermal Network of PM Synchronous Machines for Automotive Brake-by-Wire Systems

Lumped-Parameters Thermal Network of PM Synchronous Machines for Automotive Brake-by-Wire Systems

Thermal Model Approach to Multisector Three-Phase Electrical Machines

Improving Thermal Analysis Accuracy of LPTN for Vehicle Claw-Pole Alternator by Calibrating Forced Convection Coefficients Based on Experimental Results

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