Browsing by Author "Gurusamy, Vigneshwaran"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Advanced Severity Monitoring of Interturn Short Circuit Faults in PMSMs(Institute of Electrical and Electronics Engineers Inc., 2019-04-25) Qi, Yuan; Zafarani, Mohsen; Gurusamy, Vigneshwaran; Akin, Belal; 0000-0001-6912-7219 (Akin, B); 0000-0003-4697-8664 (Qi, Y); 0000-0002-3714-5081 (Zafarani, M); 0000-0002-9366-1777 (Gurusamy, V); Qi, Yuan; Zafarani, Mohsen; Gurusamy, Vigneshwaran; Akin, BelalThis paper presents a new method to estimate the severity level of interturn short circuit (ITSC) fault in permanent magnet synchronous machines (PMSMs). Instead of evaluating the fault severity by the number of shorted turns, the proposed method directly estimates the short circuit current, which is the most critical variable in ITSC faults. In the proposed method, the short circuit current generates voltage fluctuation on back electromotive force (EMF), which can be obtained via a proportional-integral (PI) estimator in the two-axis stationary reference frame. Based on the number of shorted turns information, the magnitude of the short circuit current can be estimated through the voltage fluctuation. Since the short circuit current is the main cause of deterioration in the ITSC fault, the proposed method provides an effective and straightforward way to monitor the ITSC fault. More importantly, the findings in this paper are beneficial for the fault mitigation algorithms and postfault operations. In order to verify the findings, a three-phase equivalent circuit model supported by finite element analysis (FEA) is used in the simulation. In addition, various experiments are carried out on a faulty PMSM to validate the proposed method. © 2015 IEEE.Item Design and Analysis of Integrated Planar Transformer for LLC Converter(2018-05) Gurusamy, Vigneshwaran; 0000-0002-9366-1777 (Gurusamy, V); Akin, BilalPlanar Magnetics is replacing conventional magnetic structures in many applications. Especially Planar transformers are good choice for applications requiring integrated magnetics. LLC converter takes advantage of the features of planar magnetics resulting in power density improvement of the converter system. This thesis deals with design of one such integrated planar transformer for LLC converter. Design flow of integrated planar magnetics is discussed in detail. The major issue of high frequency eddy current loss and achieving required leakage inductance are highlighted. The reason behind the high frequency eddy current losses due to proximity effect and skin effect are discussed and solution to address the high frequency loss are provide. It is shown that the solutions to reduce eddy current losses reduces leakage inductance which is good for converter systems where only magnetizing inductance of transformer plays vital role and the leakage inductance, a parasitic parameter causes undesired effects. For integrated transformer where we need significant leakage inductance, modifying design to include a leakage layer is shown to improve leakage without compromising losses.Item Stray Magnetic Flux Based Condition Monitoring Techniques for Permanent Magnet Synchronous Motors(2021-08-01T05:00:00.000Z) Gurusamy, Vigneshwaran; Akin, Bilal; Yen, I-Ling; Panahi, Issa M.S.; Gardner, Matthew; Nourani, MehrdadPermanent Magnet Synchronous Motors (PMSM) are widely used in various applications from home appliances to electric vehicles due to its advantages like high efficiency, high power density etc. The market share of this type of motor is increasing significantly in the recent decade. In order to ensure their reliable operation in safety critical system, condition monitoring tools are essential. The effective fault diagnosis and condition monitoring system reduces downtime and unplanned maintenance which saves both time and money. Though several motor attributes like current, vibration, temperature etc. can be used for diagnosis of health condition of an electric motor, stray magnetic flux around the motor housing has rich information about the health status of PM motors due to the use of high energy magnets. This dissertation presents condition monitoring techniques which are developed to address three major issues in PMSM. Stator fault is the most common electrical fault which begins as an inter-turn failure. It is essential to identify this failure at its initial stage to prevent the catastrophic damage caused by stator fault. It is shown that the fundamental component of stray magnetic flux may result in fault negative error under certain operating conditions. To overcome this problem, third harmonic component is analyzed comprehensively and proposed as a reliable fault metric throughout the entire range of operation to detect and locate the fault. Secondly, the common mechanical fault in electrical motors, bearing damage is studied. It is shown that the magnetic field of PM motors exhibit asymmetry due to the manufacturing imperfections of magnet. A stray magnetic flux-based bearing fault detection method is proposed by leveraging this asymmetry. The proposed method is analyzed extensively in both simulations and experiments. A comparative study between motor current based detection and the proposed method is also performed. In the last part of the research, a stray magnetic flux based the temperature estimation of permanent magnet is proposed. The stray magnetic flux around the motor can be correlated to the magnet temperature. However, it also is affected by the permeability variation of iron core and magnetic field generated by the stator current. A compensation co-efficient is proposed to compensate the mentioned effects and obtain the permanent magnet component of stray magnetic flux from the measured data. Then the proposed scheme is adopted to estimate the temperature of magnets online under dynamic operating conditions.