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Conference Object An Approach for Improving Performance of Sensorless Field Control(Institute of Electrical and Electronics Engineers Inc., 2018) Bulent Ertan,H.; Filci,T.; Ertan, H. BulentSensorless vector control is preferred in some applications, because there is no need for speed or position sensor. However, by their very nature, they are susceptible to making position error in rotor position estimation. As a consequence the performance of motor drives employing this technology is lower than those which employ sensors. This paper presents a new approach which identifies and uses rotor slot harmonic current component in the stator current to identify rotor position. The time taken by the algorithm used is short enough to be embedded within the vector control algorithm. The essence of the algorithm is treating the current component due to rotor slot harmonics as an amplitude modulated signal on the fundamental current component. The magnitude of this current component is identified via demodulation. Using this information rotor position and speed can be determined. This approach is tested on a commercial induction motor and some results are presented which illustrate that rotor position can be successfully determined. © 2018 IEEE.Article Citation - WoS: 28Citation - Scopus: 31A Model for the Prediction of Thermal Runaway in Lithium-Ion Batteries(Elsevier, 2024) Azuaje-Berbeci, Bernardo J.; Ertan, H. Bulent; Azuaje–Berbecí, Bernardo J.The increasing popularity of electric vehicles is driving research into lithium -ion batteries (LIBs). Thermal runaway (TR) in LIBs is a serious concern for the safe operation of these high-energy-density batteries that is yet to be overcome. A reliable model is needed to predict voltage variation, heat generation, temperature rise, and the process leading to TR of a LIB battery under its operating conditions (charging-discharging). Such a model can be used to design battery packs more resilient to thermal runaway or assess how a battery pack would perform under hazardous conditions. Furthermore, it can be used for generating a warning signal if there is a possibility of the battery going towards TR. This paper presents an approach to solving this problem, which is not currently well addressed in the literature. The approach adopted in this paper is based on a numerical analysis of a multilayered electrochemical-thermal model of LIB. Tuning the parameters of a LIB for accurate results from this numerical model is presented, as well as the details of the approach in the paper. Experiments are performed under several LIBs, and their voltage and surface temperature variations are measured under various operating conditions, including thermal runaway. The results of the experiments are compared with the predictions of the numerical simulations. An excellent agreement is observed with the experimental results, proving the accuracy of the proposed approach. This approach can be configured to give results in a few minutes. The paper also discusses how the developed approach can be used to create a TR warning during operating conditions or to change the mode of operation of a LIB before a hazard occurs.Conference Object Optimal Bore Diameter for Power Dense Traction Motor(Transilvania University of Brasov 1, 2025) Siddique, Muhammad Salik; Bülent Ertan, Hulusi; Ertan, H. BulentThe sine-wave permanent magnet brushless machine (PMSM) and Induction machine (IM) are the favorite motor types for traction applications. Modern permanent magnets (PM) are produced only in a few countries, and PM motors have higher efficiency. However, IM offers a robust, mature, rare-earth-material-free, and cost-effective. This study investigates the possibility of increasing IM efficiency by choosing an optimal bore diameter to reduce copper loss. Optimal bore diameter ensures that the motor operates at flux density levels that maintain a high power factor and give the possibility of increasing stator and rotor slot area to reduce copper loss. The investigation here is based on an experimentally verified FE model of the motor. This study illustrates that the rotor copper loss can be reduced by 25% with the choice of optimal bore diameter at rated voltage and frequency. A further 1% copper loss reduction is possible by introducing a sleeve over the stator slots to reduce air gap harmonics and, thus, surface losses on the rotor side. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 17Citation - Scopus: 24Inductance Measurement Methods for Surface-Mount Permanent Magnet Machines(Ieee-inst Electrical Electronics Engineers inc, 2023) Ertan, H. Bulent; Sahin, IlkerAnalytical performance estimation of a permanent magnet (PM) motor requires an accurate equivalent circuit model. In a lumped electrical model of a PM motor, resistance and inductances appear as passive elements, which are used to represent the phase winding resistance, inductance, core loss, etc. There is currently no available standard for parameter measurement of PM motors. In the literature, there are many studies on inductance measurement. However, they are applied to different types of motors. The purpose of this study is to evaluate those different inductance measurement methods, on the same motors, to identify whether they lead to the same result. Also, it was aimed to find out the difficulties involved in the measurement process. This study concentrates on determining the d -axis and q -axis inductances of two different surface-mount PM motors at standstill and under running conditions. The standstill measurement methods evaluated include the "current decay " method and the "dc inductance bridge " method as well as more common methods. The dependence of the inductances on the current magnitude, frequency, and excitation signal waveform is investigated. Measurements with PWM and sinusoidal ac voltage excitation are found to give similar results. The tests indicated that the "current decay " method is prone to measurement errors especially when the phase resistance is low. It is discovered that inductance measurements from standstill tests are independent of frequency for all practical purposes. Next, the same inductances are measured, while the test motors are running. The methods considered include; inductance measurement from no-load test, zero power factor (PF) load test, and unity PF load test; while the machine is in generating mode. Furthermore, a new inductance measurement method is introduced where the measurement is made while the test motor is driven with a vector-controlled drive. Finally, inductance measurement results from different standstill tests and running tests are compared and evaluated.Conference Object Citation - WoS: 3Citation - Scopus: 5Designing High Power Density Induction Motors for Electric Propulsion(Ieee, 2022) Ertan, H. Bulent; Siddique, M. Salik; Koushan, Salar; Azuaje-Berbeci, Bernardo J.Designing high-power-density electric motors for propulsion has become an increasingly important issue in the past few decades. This is not only because electric vehicles are projected to become the main private transportation means in near future, but also because of the ever so important metro and railway transport requirements. Along with these application areas, electric aircraft propulsion is also coming into focus in recent years. Electric motors for traction are required to have high torque density, high efficiency over a wide speed range and are required to be robust. In recent years, permanent magnet (PM) motors became the favorite choice for such applications because of their higher efficiency than other types of motors. Increasing demand for permanent magnets is likely to cause supply problems. Therefore, permanent magnet-free alternative motor types are of much interest. In this paper, the authors present the design of a 125 kW induction motor for railway application. This design has 3-times the power density of a commercial induction motor. The designed motor is manufactured and its test results are used for establishing an accurate finite-element model for the prediction of its performance. This model is used to investigate the effect of magnetic loading choice, slot shape and magnetic material choice on the efficiency of the motor. It is shown that with the same basic dimensions the efficiency of the motor can be increased to 96% which is comparable with a similar size PM motor.
