M. R. Barzegaran

Fault Diagnosis of the Asynchronous Machines Through Magnetic Signature Analysis Using Finite-Element Method and Neural Networks

Summary form only given. 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 motors 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.

Optimum Equivalent Models of Multi-Source Systems for the Study of Electromagnetic Signatures and Radiated Emissions From Electric Drives

An optimum equivalent electric machine model for 3-D finite element (3DFE) simulation and evaluation of radiated electromagnetic field emissions in a multi-machine environment is presented. A typical example of such systems includes electric motors and cable runs electric drives. Initially, the detailed geometrical model of the machine was simulated in a 3DFE quasi-static electromagnetic domain. An optimum equivalent model was created using an optimization process based upon the difference between the observed electric and magnetic far fields from both the detailed geometrical and the equivalent models. The equivalent model was validated in several examples. The computed electromagnetic signature results from the equivalent model show acceptable accuracy as compared with the detailed geometrical model of the machine. The equivalent machine model was obtained with significant reduction in computation time needed for the evaluation of the radiated fields. The proposed model can be used as an effective method for the simulation of signatures and radiated electromagnetic field emissions from electric drives in computationally intensive environments.

Investigating short-circuit in power transformer winding with quasi-static finite element analysis and circuit-based model

Detecting and removing minor faults in power transformer winding is essential because minor faults may develop and lead to major faults and finally irretrievable damages occur. In this paper in order to detect the position of short-circuit in the winding, frequency response of the input impedance of a power transformer is analyzed. Common short-circuits are categorized and the results are compared, then the behavior of frequency response due to disk-disk short-circuit is investigated. To increase the accuracy of analysis, innovative approach in finite element analysis is offered. This approach termed Electromagnetic quasi-static considers both magnetic and electric characteristics of power transformer. Simulation is fulfilled by interconnecting between finite element analysis and circuit-based model for employing short-circuit.

Efficient Wireless Power Charging of Electric Vehicle by Modifying the Magnetic Characteristics of the Transmitting Medium

There is a developing enthusiasm for electric vehicle (EV) innovations because of their lower fuel utilization and greenhouse emission output. Integrating EVs with highway wireless power transfer (WPT) technology can appropriately reduce charging time and possibly expand their travel distance. There are several issues with the current WPT technology for EVs: 1) low efficiency due to large coil-coil distance and 2) slow charging time. Two ideas are proposed in this paper to increase system efficiency: 1) using a modified cement for covering the transmitting antenna area and 2) using high frequency wide bandgap switches, which can transfer a high amount of power in a short time. The optimization study of the receiving and transmitting coils is implemented with and without a core through 3-D finite-element analysis. The physics-based analysis is coupled with circuit-based analysis for utilizing high frequencies wide bandgap switch (SiC MOSFET). On the material side, the electromagnetic and mechanical properties of the modified cementitious composite are characterized and the results show significant improvement in the system efficiency.

3-D FE Wire Modeling and Analysis of Electromagnetic Signatures From Electric Power Drive Components and Systems

A 3-D finite-element (FE) optimized equivalent source numerical model for the analysis of low frequency electromagnetic field signatures in electric drives is proposed. An example electric drive system including a synchronous generator, an induction motor and power cables connecting a load is used to implement the model. The arrangement of the system setup is developed using a fully detailed 3DFE model to verify and compare with the results of the proposed equivalent source model. The proposed technique provides the exact field solution without large computational even with the presence of superposition. The equivalent source model (wire model) is created based on numerical techniques and physical theory of wave propagation. The superposition of the various components in this study is considered. The results of the proposed wire models match the results of the original models. For further verification, experimental results of the setup are compared with the numerical results. The importance of the proposed equivalent source is that it can be used for the evaluation of electromagnetic signatures and radiation patterns at the design stage. This enables performing various designs iterations to achieve compliant designs to electromagnetic compatibility standards. The proposed model can also be used for dynamic monitoring and diagnosing failures in the system.

A Generalized Equivalent Source Model of AC Electric Machines for Numerical Electromagnetic Field Signature Studies

A generalized equivalent source model of AC machine for electromagnetic signature studies is proposed to provide the exact field solution without the need for using large numerical or analytical computation efforts. The model was created using a wire-modeling of the machine windings designed based on the electric displacement field and current density of the actual machine. In addition, an optimization process is implemented to have a comprehensive equivalent model that is appropriate for various geometrical sizes and terminal voltages. A finite element model was employed for developing the equivalent source model. For verification, the radiated field results, from both the detailed AC machine numerical models and the equivalent source models for various operational cases, are studied and compared. The results of the equivalent source model match the results from the detailed machine models. Using the equivalent source model, we can evaluate radiation and stray field effects for electromagnetic compatibility (EMC) and standard evaluation studies with a small computational effort.

An equivalent source model for the study of radiated electromagnetic fields in multi-machine electric drive systems

In this paper we develop an equivalent model for electrical machines which is useful for the study of radiated electromagnetic fields in a multi source environment. The proposed models are created from a representative cylinder loops and cubes carrying a set of currents in the cylinder branches as well as voltages at the nodes of the cubes or loops. The amount of current and voltage of the model are obtained based on the current density and electric field displacement of the windings of the actual machines. The geometry of the cube model were calculated based upon a genetic algorithm-based particle swarm minimization process taking into consideration the actual size and the operating conditions of drive system being studied. To investigate the accuracy of model, the electric and magnetic fields propagated from the model at a point far from the drive systems were compared with the actual model. The simulated results show excellent accuracy and practical simulation time compared to full three dimensional finite element model of actual machine. This makes the proposed model ideal for the development of accurate tools for the estimation of radiated electromagnetic field emissions from electric drives and multi conductor environments during their development stage. For verification, the equivalent model is used in multi machine scale and the results of the equivalent model of multi machine case match the result of the actual model case.

Electromagnetic Signature Study of a Power Converter Connected to an Electric Motor Drive

This paper investigates the stray magnetic and electric fields of a multifunctional power converter operation while connected to a system involving an induction motor. The impacts of the switching techniques on the radiated fields of the converter were studied for the purpose of electromagnetic interference (EMI) evaluation and fault detection. This was achieved through the inspection of the magnetic and electric fields. Two of the most commonly used switching techniques were implemented through a hardware-in-the-loop system studied in terms of the stray. Various fault and failure conditions were applied to the converter to monitor the converter condition through the stray field observations. A coil and a rod antenna were connected to an EMI receiver to capture the fields. The fields were employed in further analyses. The harmonics and interharmonics of the stray fields were studied in detail for system monitoring purposes. The importance of this paper is to enable the evaluation of the optimum switching pattern for lower EMI field levels from the converter and for condition monitoring and fault diagnosis purposes.

Multiobjective Design Optimization Using Dual-Level Response Surface Methodology and Booth's Algorithm for Permanent Magnet Synchronous Generators

This paper studies a dual-level response surface methodology (DRSM) coupled with Booths algorithm using a simulated annealing (BA-SA) method as a multiobjective technique for parametric modeling and machine design optimization for the first time. The aim of the research is for power maximization and cost of manufacture minimization resulting in a highly optimized wind generator to improve small power generation performance. The DRSM is employed to determine the best set of design parameters for power maximization in a surface-mounted permanent magnet synchronous generator with an exterior-rotor topology. Additionally, the BA-SA method is investigated to minimize material cost while keeping the volume constant. DRSM by different design functions including mixed resolution robust design, full factorial design, central composite design, and box-behnken design are applied to optimize the power performance resulting in very small errors. An analysis of the variance via multilevel RSM plots is used to check the adequacy of fit in the design region and determines the parameter settings to manufacture a high-quality wind generator. The analytical and numerical calculations have been experimentally verified and have successfully validated the theoretical and multiobjective optimization design methods presented.

Using gallium nitride DC-DC converter for speed control of BLDC motor

Utilizing GaN (Gallium Nitride) DC-DC converter for speed control of BLDC (Brushless DC) Motor is investigated in this paper. The proposed system replaces the well-known Si-based switches by GaN FETs which are faster by minimum ten times and much compact that it recedes the size of Switched Mode Power Supply (SMPS) application. The contemplated system uses a GaN-based DC-DC Resonant Converter to drive and regulate the speed of a BLDC Motor at a switching frequency as high as 100 kHz. The processor used is xPC target in conjunction with NI PCI-6251 Data Acquisition device with a capability of send/receive high frequency data between MATLAB/Simulink to hardware and vice versa. To establish the conduct of this system, both simulation and experimental outcomes have been illustrated. The high efficiency, high accuracy, and low power loss along with lower weight and volume of the converter are the advantages of this system.