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Due to their harsh operational environment, losses and vibrations are vital performances in the design stage of double-canned induction motors (IM) for the submergible rim-driven thruster (SRDT) applications. However, the traditional design approaches cannot be directly applied to that family of IMs as more influential factors (i.e., the flat structure, large diameters, eddy current losses in the cans, and the local saturation effect) should be attentively considered. This study presents a robust electromagnetic design procedure for double-canned IM, combining the traditional magnetic circuit method (MCM) and the finite element method (FEM). Firstly, the improved MCM is adopted to determine the size of the machine, including the stator outer and inner diameters, the core length, etc. Moreover, the reasonable ranges of the critical parameters are obtained. Afterward, considering the losses and electromagnetic forces, time-stepping FEM is used to perform an excellent analysis of the essential parameters of design, and the thermal and stress analyses are coupled to evaluate the optimal design schemes. A design example of a 3 kW double-canned IM is presented, and the prototype is manufactured. Loss and noise experiments are performed to verify the effectiveness of the given procedure. [ABSTRACT FROM AUTHOR]

The proper magnetic design is one of the most difficult and critical phases in developing an inductive power transfer system, especially for electric vehicle charging. In this communication, a fast and an efficient improved Tabu search algorithm coupled with 2-D finite-element analysis (FEA) was used to determine the optimum design parameters of power pads. A two-objective optimization problem was investigated considering the magnetic coupling, misalignment (horizontal, vertical, and rotational), as well as the cost. The double-D power pad structure was considered as a case of study, and the most effective design parameters were obtained. The 2-D FEA was utilized to calculate the coupling factor at different misalignment conditions. For verification purposes, the system coupling performance and cost are analyzed using the optimum design parameters and compared with three other designs presented in the literature. The proposed optimized design shows the best coupling performance with moderate cost. The results proved the validity and advantages of the proposed design methodology. [ABSTRACT FROM AUTHOR]

The paper presents an advanced quasi-FEA technique on the iron losses prediction using Bertotti's iron loss separation models, in which a curve fitting is taken into account for coefficients calculation of each model. Moreover, the skin effect and saturation consideration are applied in order to check the accuracy through the relative error distribution in the frequency domain of each model from low up to high frequencies 50 to 700 (Hz). Additionally, this comparative study presents a torquespeed-flux density computation that is discussed and presented. The iron loss characteristics of a radial flux permanent magnet synchronous machine (PMSM) with closed-slots and outer rotor topology are also discussed. The quasi-finite-element (FE) analysis was performed using a 2-D and 3-D FEA, where the employed quasi-2-D FEA is proposed and compared with 3-D FEA, and along with experimental verifications. Finally, all the iron-loss models under realistic and non-ideal magnetization conditions are verified experimentally on a surface-mounted PMSG for wind generation application. [ABSTRACT FROM AUTHOR]

Inductive power transfer (IPT) technology has been approved to be convenient and reliable interface for charging and discharging the electric vehicles (EVs). Precise model for such system can help designers and researchers to anticipate, optimize, and evaluate its behavior amid the development. Thus, this paper presents a physics-based co-simulation platform for the bidirectional IPT system (BIPTS) in EVs’ applications. The platform is established through the coupling between finite element and circuit analysis. The power electronic converters and controllers are developed in Simulink; and the power pads are modeled in Magnet environment. The two parts are lined together through the compatible Simulink plug-in tool. In addition, a state-space dynamic mathematical model for the same BIPTS is derived and implemented in MATLAB environment. A 1.2 kW BIPTS is analyzed under different dynamics by both models and the results are compared. The effect of the nonlinearities and the magnetic material characteristics on the BIPTS's performance is assessed, in terms of errors and harmonics analysis. The analysis considered both the full and light loading operating conditions in the system. Finally, a small-scale prototype for a BIPTS is built, tested, and compared with the co-simulation results for verification purposes. The proposed co-simulation could provide accurate prediction for the system's dynamics, during both charging and discharging operation. The scheme is generic and can be easily expanded to different pad structures, compensation networks, and converter topologies. [ABSTRACT FROM PUBLISHER]

This paper presents a method for the identification of winding failures in induction motors. The types of failures include unbalanced currents flowing into the motor and short-circuit of the winding. The radiated magnetic field of a typical induction motor was studied while various types of failures applied to the machine. The implementation was performed by applying different types of unbalanced currents flow into the machine. The fields were obtained from both numerical finite-element simulations as well as from experimental setups. The turn to terminal and turn to turn short-circuit of the motor's winding were studied. The frequency response of the 3-D finite-element (3DFE) model of the motor was implemented up to high-order frequencies. The numerical results were compared with the measurement results. The fields with unbalanced currents and short-circuit conditions were identified by studying the harmonic orders of the radiated magnetic fields. This was also implemented using artificial neural networks (ANN). The results show that the signature study of the experimental as well as the simulation models can be utilized for failure identification in electric motors with a high level of accuracy. [ABSTRACT FROM PUBLISHER]

In this paper, the inter-turn short circuit fault detection in permanent magnet synchronous machines (PMSM) using an open-loop physics-based back electromotive force (EMF) estimator is presented. The back EMF estimator is designed based upon a current mode tracking scheme. The thermal and saturation aspects of the machine are considered in the design of the estimator. The design procedure and stability criteria of the estimator are presented in detail. The fault detection is carried out based on the difference between the estimated back EMF and a reference back EMF. A 0.8 (kW) PMSM is studied experimentally as well as numerically under different inter-turn fault and operational contingencies. The numerical modeling is accomplished by a finite-element-based model coupled with the thermal network and polluted with inter-turn fault. The acceptable agreement between the simulated and experimental result validates the modeling process. The back EMF estimator fault detection system is led to discriminative inter-turn fault signatures in a fraction of second for wide speed range even in the presence of harmonic loads and dynamic eccentricities. [ABSTRACT FROM PUBLISHER]

A model for electrical machines useful for radiated electromagnetic field studies in a multi-source environment is proposed. The various aspects of electromagnetic signature are considered. This model was created from a representative rectangular prism carrying a set of unbalanced currents in its branches. The geometry and the currents of the equivalent model were calculated based upon a genetic algorithm-based particle swarm optimization process taking into consideration the actual size and the operating conditions of the drive system being studied. The electric field was chosen as the objective function, which is the main element of the optimization. The simulated results show acceptable accuracy and excellent simulation time as compared to the full 3D FE model of the actual machine. Various types of signature studies of the model were conducted. This included stationary and time analysis in addition to the effect of rotation of the machine. For verification, we utilized two machines in a connected system to study and compare the results with their actual model. The results show satisfactory accuracy. The practical implication of this effort is in the fact that, with this equivalent model, we can evaluate radiation and stray effects for EMC evaluation at the design stage. [ABSTRACT FROM AUTHOR]

In this paper, a physics-based high-frequency (HF) model of switching power converters including the insulated gate bipolar transistor (IGBT) unit cells, heat sink, and connective printed circuit board (PCB) traces combined in a single electrical circuit is presented. The IGBT model includes the HF stray components superimposed on the well-known Hefner IGBT model. The HF components were calculated using a 3-D quasi-static finite element (3-D FE) analysis. The proposed complex model of the IGBT was verified both numerically and experimentally at different switching frequencies. The computed IGBT model was used in a low–high frequency model of a motor-drive system, and the common mode ground current was experimentally verified showing excellent results. [ABSTRACT FROM AUTHOR]

An online hardware-in-the-loop finite-element (FE)-based design optimization procedure is developed for the computational prototyping of coupled electric motor-drive system. A design optimization case for development of permanent magnet (PM) machine drive is presented. The physical representation of the machine is achieved by modeling the machine as a current adjustable load. The mutual interaction of the machine and the existing drive is taken into account by physical connection of the drive to a current adjustable load. The current adjustable load can be automatically renewed due to the design parameter changes of the machine being designed in an optimization process. The optimal design of the PM machine example is realized using the proposed technique and both numerical and test results are discussed. [ABSTRACT FROM AUTHOR]

This paper deals with an optimal design of surface-mounted permanent magnet motor geometry for achieving minimum torque ripple, minimum RMS value of phase current, and minimum total harmonic distortion of phase currents, simultaneously. A classic multiobjective function is formed as a combination of these single objectives. A dynamic physics-based phase variable modeling approach is used to indirectly couple the motor geometry in the finite element domain to the drive circuit in a simulink environment. The physical behavior of motor is calculated by nonlinear transient FE analysis with motion. A fast hybrid genetic-particle swarm optimization process is developed for shape optimization of the motor. The results before and after optimization show the expected performance improvements while reducing magnet material and copper size. [ABSTRACT FROM PUBLISHER]

This paper proposes a frequency-dependent electromagnetic model for armored power cables using Coupled circuit-field method. The model parameters were obtained by conducting a series of coupled field-circuit studies at different frequencies. The cable capacitance matrix is calculated using an electrostatic FE analysis. The frequency response of the cable was obtained by coupling the cable FE domain model and external electric circuits. This technique allows the physical representation of the nonlinear magnetization behavior of the cable shell as well as the frequency dependence of the cable parameters. This frequency response was then fitted with rational function approximation. The resulting vector fitting (VF) rational function was then represented by an equivalent electrical network. This model represents the cable's high-frequency dynamic behavior to account for overvoltages or spikes in the current waveforms. [ABSTRACT FROM PUBLISHER]

This paper investigates the effect of the switching frequency of pulse width modulation (PWM) motor drives on radiated Electromagnetic Field Interference (EMI) due to common Mode (CM) ground currents. A technique with two successive steps is used to simulate conducted as well as the radiated EMI. At first, a high-frequency permanent magnet (PM) machine model, a high-frequency cable model, and a low-frequency IGBT drive model are employed to simulate the common mode (CM) current through ground paths, conducted EMI. The radiated EMI is modeled as a time harmonic electromagnetic wave which is propagated through all the components of the electric drive system. The Radiated EMI were evaluated by 3DFE analysis while the simulated common mode (CM) ground current from the first step was used as the supply source of the radiated fields. The results of this two step technique follow the expected patterns and provides a novel numerical alternative during the design and development stage of electric motor drive systems. [ABSTRACT FROM PUBLISHER]

This paper proposes a computational high-frequency transformer model. The model parameters are obtained by using coupled-circuit-finite-element (FE) nonlinear analysis. The frequency response of the transformer was obtained by coupling the transformer FE model and external electric circuits. This technique would allow the physical representation of the nonlinear magnetization behavior of the transformer as well as the strong frequency dependence of the transformer parameters. The self capacitance of each conductor and the mutual capacitances between the turns were calculated by an electrostatic FE analysis. The capacitance order was then reduced to a lower order by shifting the capacitances connected to internal nodes (windings) to the external ones (coil nodes). The resulting reduced capacitances, along with the inductances and resistances, were then used in the circuit domain of the coupled circuit-FE analysis. The transformer frequency response was then obtained from FE analysis. This response was then fitted with rational function approximation. This rational function approximation is then used to construct a frequency-dependent branch (FDB) which is connected in parallel with the nominal frequency transformer model. The FDB branch represents the transformer high-frequency behavior over a wide frequency range. The implementation is performed on a 125-kVA transformer. The developed model terminal behavior was tested under different operating conditions. This includes different switching frequencies and connecting cable length. [ABSTRACT FROM AUTHOR]

A new FE-circuit coupled model is proposed to simulate the electromagnetic field interference (EMI) caused by terminal overvoltage and ground current of electric machines connected to driving circuits. The high frequency effects due to the PWM drive were considered in the transient FE-circuit coupled model of the motor using a two-step procedure. First, the resistance in each individual winding turn of a coil is evaluated by time harmonic high frequency FE analysis considering skin and proximity effects. The capacitances of the coil were calculated by an electrostatic FE analysis to form a distributed parameter model of the coil in each conducting region. Second, a lumped parameter model for the coil was obtained through a matrix reduction technique. The lumped models of the different coils were connected in series to form a per phase winding model. The FE-circuit coupled model of the motor is tested in a motor drive to evaluate the terminal over voltages and ground currents. The numerical results were successfully verified by the corresponding laboratory test measurements. The proposed model can be used as a novel computational prototyping tool which would allow the development to design and final product stages to be completed without the need for repeated build and test procedures in an industrial environment. [ABSTRACT FROM AUTHOR]

This paper presents a fast and accurate brushless dc motor (BLDC) phase variable model for drive system simulations. The developed model was built based on nonlinear transient finite-element analysis to obtain the inductances, back electromotive force as well as the cogging torque. The model was implemented in a Simulink environment through the creation of an adjustable inductance component to account for the dependence of inductances on rotor position. Since no dq model for BLDC actually exists, the significance of this work is that it provides an accurate equivalent circuit model of BLDC motors for utilization in simulation environments. Using the developed model, the sensorless control and the torque ripple control issues were investigated and the simulation results show its practical effectiveness. [ABSTRACT FROM AUTHOR]