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In this paper, a new breast cancer detection method is presented that combines thermography and high-frequency excitation techniques. The proposed method uses distribution and variation of the temperature on the breast surface to estimate the location and size of a malignant tissue (a cancerous tumor). The idea of this paper stems from the analysis of the radio frequency (RF) radiation effects on the human body. In this paper, a description of RF effects on the human body and simulation results are provided. To validate the proposed method, a multilayer 3-D breast model is simulated. First, breast tissue is excited with different types of RF antennas, which is followed with an electromagnetic analysis. Next, the heat transfer equation is applied for thermal analysis to estimate the distribution of surface temperature. Simulation results show that both the temperature and the specific absorption rate increase as the tumor becomes bigger or closer to the surface. Finally, thermal responses of multiple tumors are employed to estimate breast cancer existence. [ABSTRACT FROM AUTHOR]

Prediction of acoustic noise distribution generated by electric machines has become an integral part of design and control in noise sensitive applications. This paper presents a fast and precise acoustic noise imaging technique for switched reluctance machines (SRMs). This method is based on distribution of radial vibration in the stator frame of the SRM. Radial vibration of the stator frame, at a network of probing points, is computed using input phase current and phase voltage waveforms. Sequentially, the acceleration of the probing network will be expanded to predict full acceleration on the stator frame surface, using which acoustic noise emission caused by the stator can be calculated using the boundary element method. [ABSTRACT FROM AUTHOR]

Vibration and acoustic noises are viewed as a drawback in switched reluctance machines (SRMs), which prohibit their widespread use in noise sensitive applications. Double-stator SRMs (DSSRMs) can be considered as a solution to this problem by incorporating an improved magnetic configuration, which reduces the radial forces in the machine. This paper compares structural behavior of a DSSRM and a conventional SRM using a multi-physic analysis. An electromagnetic finite-element (FE) method is used to calculate force density at various parts of the stator surface in both machines. These force densities are then used in a structural FE analysis to compute acceleration, deformation, and velocity of the vibrating surface at selected point on the outer surface of the machine. [ABSTRACT FROM AUTHOR]

Origins of vibration in switched reluctance machines (SRMs) are investigated. Accordingly, an input–output model based on the mechanical impulse response of the SRM is developed. The proposed model is derived using an experimental approach. Using the proposed approach, vibration of the stator frame is captured and experimentally verified. [ABSTRACT FROM PUBLISHER]

Switched reluctance machines provide a feasible solution for automotive applications. However, a small and low cost power electronics driver is of interest for this purpose. This paper presents a control algorithm for a single-bus star-connected switched reluctance drive system. This algorithm enables the conventional Miller topology to control the phase currents in the multiphase excitation mode of operation. This control algorithm is introduced for motoring and generating modes of operation. The introduced algorithm is simulated under motoring and generating modes. Afterward, experimental measurements are illustrated to prove the practicality of the proposed concept. [ABSTRACT FROM AUTHOR]

This paper presents the dynamic behavior of multiport power electronic interface (MPEI) under load/source disturbances. A cascaded topology for MPEI is considered. This system is capable of power management for local generations, loads, and storage systems. Large-signal and small-signal models for MPEI are developed. These models are combined with corresponding control algorithms. Simulated and experimental transient responses to disturbances on each port are presented. The behavior of MPEI in response to each disturbance is analyzed. Simulation and experimental results are compared in order to verify the model. [ABSTRACT FROM PUBLISHER]

This paper presents a very high frequency dc-dc boost converter. This design features low voltage stress on the switch, high efficiency, and simple control. The low energy storage requirements provide a more effective integration. A proposed resonant gate driver provides variable duty cycle and possibility of the control of the converter at very high frequencies. A 60-MHz prototype of the proposed converter is designed and implemented. Experimental results demonstrate the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

This paper presents a power distribution system that prioritizes the reliability of power to critical loads within a community. The proposed system utilizes reinforcement learning methods (Q-learning) to train multi-port power electronic interface (MPEI) systems within a community of microgrids. The primary contributions of this article are to present a system where Q-learning is successfully integrated with MPEI to reduce the impact of power contingencies on critical loads and to explore the effectiveness of the subsequent system. The feasibility of the proposed method has been proven through simulation and experiments. It has been demonstrated that the proposed method can effectively improve the reliability of the local power system—for a case study where 20% of the total loads are classified as critical loads, the system average interruption duration index (SAIDI) has been improved by 75% compared to traditional microgrids with no load schedule. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to provide an efficient computational model for fast and accurate calculation of electromagnetically induced vibrations in electrical machines. Although a three-phase permanent-magnet synchronous machine has been used in this paper, the same methodology can be extended to other types of electric machinery. A brief comparison between the different methods for structural analysis in electrical machines is introduced. The method proposed in this paper uses finite-element analysis in order to extract the impulse responses that are used in calculating the vibration. A field reconstruction method is used for the electromagnetic field analysis. [ABSTRACT FROM PUBLISHER]

Obtaining an accurate estimate of the magnetic flux in permanent magnet synchronous machines is a considerable challenge especially at very low speeds and in the presence of parameter variations. Significant research has been done to develop methods of estimation that can overcome issues such as drift in numerical integration and variations in machine parameters. This paper proposes a new technique for the estimation of the magnetic flux in permanent magnet synchronous machines. The proposed technique is based on the field reconstruction method. Experimental and simulation results for a permanent magnet synchronous machine are provided to validate the precision of the proposed flux estimation technique. [ABSTRACT FROM PUBLISHER]

The continuous effort to improve efficiency, reduce particle, and greenhouse gase emissions leads to the emergence of the concept “more electric.” This concept helps to boost the performance as well as the flexibility of the domestic and vehicular applications; however, on the other hand, it excessively burdens current power networks (including vehicle power systems). In order to remedy this problem, simultaneous usage of renewable sources and energy storages is encouraged. A multiconverter system is commonly adopted to process the renewable power in form of distributed generation. However, due to the discrete structure of such systems, power flow and load regulation are coordinated via communication channel, which inevitably reduces the reliability and dynamic response of the system. This paper presents the concept of multiport power electronic interface (MPEI) for renewable energy sources and storages. With a unified modular topology and highly integrated digital control system, controlled quasi-current source is achieved for each input port in both steady-state and transient power-sharing modes. MPEI analysis, modeling, design, and system operation are treated in a systematic manner in this paper. Both power stages and digital control system are implemented for a five-port MPEI. Experiments are conducted under meaningful operation scenarios. The results are presented to prove the feasibility of MPEI concept and system design methodology. [ABSTRACT FROM AUTHOR]

Fuel cells (FCs) are being considered as a potential alternative in long term to replace diesel/gasoline combustion engines in vehicles and emergency power sources. However, high cost and slow dynamic response of FC still persist as the main hurdles for wider applications. To remedy this problem, an energy storage system with adequate power capacity has to be incorporated. This paper presents a novel control design for FC-battery hybrid power system which enables both active current sharing and power source management control in such hybrid systems. Different hybrid power system structures are investigated and evaluated; dual-converter structure and four modes of operation are defined to provide efficient and sustainable solution to such a hybrid power system. A novel integrated control system with inherent current sharing and generation mode swapping capability is proposed; based on system component status, the control system is able to regulate the output power from each source under different scenarios. The dedicated control system is implemented in a TMS320F2812 DSP, and experimental results for an PC-battery-based uninterruptible power supply are provided to demonstrate the static and dynamic performance of the control system. [ABSTRACT FROM AUTHOR]

In high-performance three-phase pulsewidthmodulated (PWM) converter systems used in generator and motor drives, failure of current sensors will directly interrupt the system performance, and will even cause disastrous consequences. Redundancy in design is one of the popular choices to overcome this issue. However, this usually leads to an undesirable increase in size and cost. This letter presents two novel model-independent current reconstruction methods for three-phase PWM converter systems based on space vector modulation. Using the proposed sensor placement and software algorithm, phase currents within a three-phase converter can be reconstructed to an acceptable level of accuracy under single-survived-sensor (S3) scenario. A hardware prototype is built and fault tolerant algorithm is implemented using a DSP (TMS320F2812). Experiments are conducted under worst-case scenario to verify the flexibility of sensor placement/converter layout and software algorithm. [ABSTRACT FROM AUTHOR]

Development of a precise dynamic model is a critical step in design and analysis of optimal control strategies for switched-reluctance machines (SRM). This paper is focused on important issues concerning the development of such models and their subsequent use in designing control strategies for SRM drives. The main goal in modeling is to provide a good accuracy over the entire speed and torque range. To achieve this objective, the following requirements need to be met: 1) a good accuracy in matching the inductance of each stator phase; 2) inclusion of mutual effects when significant overlap among phases exists; 3) inclusion of short flux-path operation in each electrical cycle when significant overlap among adjacent phases exists; and 4) capability for autocalibration to cope with parameter variations incurred by manufacturing imperfections and operational conditions. In this paper, in addition to an in-depth discussion of the above factors, a practical modeling approach along with an autocalibration strategy is presented. A simple test collects the necessary data in developing the proposed model. Inherent separation among mechanical, electrical, and control time constants has been used to develop the autocalibration process. Experimental results are presented to validate the proposed method. [ABSTRACT FROM AUTHOR]

Vibration caused by torque ripple and radial force harmonics is a concern in many applications of permanent magnet synchronous machines (PMSMs). Alternative methods of machine design and/or stator excitation to minimize torque ripple have received considerable attention in recent years. Comparatively, methods to minimize radial force harmonics have received less attention. In this paper, a field reconstruction (FR) method is derived that provides a designer with the capability to rapidly determine the radial and tangential components of force under arbitrary stator excitation. Using the field reconstruction method, stator current waveforms that minimize the ripple of both torque and radial force are derived subject to the constraint of maintaining a satisfactory level of torque density. [ABSTRACT FROM AUTHOR]

Proper synchronization of the excitation with respect to the rotor position is essential in optimal control of switched reluctance motor (SRM) drives. To avoid additional cost, size, and unreliability caused by the external position sensors, magnetic status of the SRM can be directly monitored to detect commutation instants. A one-to-one correspondence between magnetic status of the SRM and rotor position removes the need for an explicit access to the rotor position. In order to obtain a good precision over the entire speed range, educated modifications on the structure of the sensorless strategy is necessary. This is due to the impact of the operational regions on dynamic behavior of the SRM. In addition, introduction of SRM technology to industrial and domestic applications has raised the need for four-quadrant operation of the SRM drives. The present paper introduces a range of strategies that are necessary to accommodate this requirement in a sensorless format. Our experimental findings indicate that high-grade sensorless operation in a four-quadrant SRM drive is possible and can be integrated in a variety of applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel analytical model for a switched-reluctance machine (SRM) based on decomposition of its inherent double joint magnetic saliencies due to rotor and stator salient poles and saturation of magnetic field at high stator currents. With this method, the magnetic characteristics of the motor, such as flux linkage and incremental inductance, are decomposed to vector functions of rotor position and phase current. Dynamic state and torque equations for the SRM are derived on the basis of this representation. The proposed model is appropriate for on- line identification and for sensorless position control algorithms. It is easy to implement and computationally efficient. Comparison of the predicted motor magnetic characteristics to machine data from finite-element analysis verifies the accuracy of the model. [ABSTRACT FROM AUTHOR]

Focuses on the elimination of position sensors in switched reluctance motor (SRM) drives. Applicability of SRM drives; Importance of rotor position sensing in SRM control; Positioning of the sensors to decrease drive system reliability.

Focuses on a study which examined the capabilities of switched reluctance motor (SRM) applications to electric vehicles (EV) and hybrid electric vehicles (HEV). Significance of design of the reluctance motor in EV and HEV; Static characteristics of SRM; Description of a nonlinear SRM model; Methodology; Examples; Experimental results; Conclusion.

The performance of lithium-ion batteries is contingent on the operational temperature and applied current rate. Especially in electric vehicle application, repeated heavy-duty drive cycles impose intense thermal stress on batteries, resulting in safety concerns. This paper explains the electrochemistry within the battery and analyzes the dependence of battery internal parameters on temperature and current rate based on their electrochemical nature. In addition, this interdependence is used in the equivalent circuit model to predict the battery behavior under different drive cycles. Finally, the behavior under different drive cycles is analyzed to improve the battery performance in electric vehicles. [ABSTRACT FROM AUTHOR]

Here we present a comprehensive analysis of structural performance of Induction Machine (IM) and Switched Reluctance Machine (SRM) rotors under different operational conditions. Electric machines are susceptible to forces of diverse origins. In addition to traditionally considered magnetic and centrifugal forces, this article discusses independent and inclusive effects of thermal expansion and shaft attachment techniques on structural integrity of the machines. A comparative analysis of structural performance of IMs and SRMs has also been performed, under a range of scenarios, to facilitate application-specific machine selection from a structural perspective. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the advances in multi-objective design based on genetic algorithm, polynomial regression, and particle swarm optimization techniques.

The author discusses the 2nd part of the journal's special section on electric machinery and adjustable-speed motor drives. The section focuses on recent developments on advanced control and diagnostic techniques in electromechanical energy converters and introduces the artificial intelligence techniques in magnetic design and optimal control of electric machinery. It is composed of 17 articles demonstrating trends in the state-of-the-art research and development in academia and industry.

The article informs that recent advancements in design, control and diagnostics in electromechanical-energy converters have motivated this special section on electric machinery and adjustable-speed motor drives-part I of the periodical "IEEE Transactions on Industrial Electronics." It is stated that efficiency in generation and consumption of electricity is a factor by which the future energy challenges will be affected. Due to this factor, as also stated, significance of research and development pertaining to conversion of electromechanical-energy continues to attract substantial attention from academia, industry and governments around the world.

Techniques used for breast cancer detection usually incorporate Infrared Thermography (IRT) to locate abnormal hotspots or asymmetry in a thermal texture map. This can be unreliable due to various individual differences from one person to another. In this paper, a detection method that is independent of the aforementioned limitations is proposed. This technique is a combination of thermal imaging and high-frequency excitation. This technique is based on the fact that the differences in electromagnetic and thermal properties of abnormal (malignant) tissue and the surrounding normal tissue will result in a noticeable difference in temperature increase after exposure to high-frequency excitation. A three-dimensional (3-D) finite-element method (FEM) has been used to simulate the thermal behavior of breast tissue exposed to antenna excitations. Finally, the effectiveness of this technique was tested in a series of experiments using a life-sized breast phantom. [ABSTRACT FROM AUTHOR]

This article presents an efficiency optimization of double-sided LCC compensation network for inductive power transfer systems. Compensation factors of the primary and secondary LCC circuit are defined and optimized analytically. The investigation shows that the secondary compensation factor $k_{rx}$ highly influences the copper loss of the wireless coupler, whereas the primary compensation factor $k_{tx}$ should not be large in order to reduce the switching loss and conduction loss of the input inverter. With a proper selection of these compensation factors, it is possible to achieve a high and sustained efficiency over a wide range of load and misalignment. In order to demonstrate the feasibility and validity of the proposed method, a scaled-down prototype has been implemented with the operating frequency of 85 kHz, transfer gap of 170 mm, and misalignment of up to 100 mm. Experimental results show a good agreement with the theoretical analysis. The peak efficiency of the proposed system is 91.6% under the perfect alignment at the coupling coefficient of 0.172. The efficiency still remains at 86.37% even under 100-mm misalignment with the coupling coefficient of 0.123. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on the geometry and manufacturing of switched reluctance machines (SRM), its design and control, and its research.

The symmetric structure conventionally used in two-phase switched reluctance machines (SRMs) leads to dead torque zone and issues with startup. When a phase is at the fully aligned position with respect to the rotor, the complimentary phase is completely unaligned. Within this region, excitation of either phase fails to generate sufficient startup torque. Significant research has been focused on the design of machines with large, unidirectional startup torque specific to the direction of rotation required by the given application. In this work, a conventional two-phase SRM is analyzed to reveal the underlying geometric constraints leading to startup difficulties. To overcome this, a phase shift design strategy is proposed to ensure both large starting torque and bidirectional startup capability. The design is investigated and validated through both simulation and experiments, and the results show the validity of this new configuration. [ABSTRACT FROM PUBLISHER]

In a yet another effort to produce better permanent magnet (PM)-less rotor-winding-less brushless electric motor drives, this paper reports work related to multiphase (m =6) high saliency rotor dual-flat-top alternative current control brushless dc (BLDC) reluctance machine drives. The aim is to produce high torque density, low loss/torque in a PM-less rotor-winding-less machine by full usage of machine windings and core and of inverter kVA. A new derivation of the principle of operation, essential rotary and linear machine topologies, and a 2-D finite-element method (FEM) analysis for torque density and torque pulsations on an already built (6 phase, 6 poles, 35 N $\cdot$m) lab prototype are made available and show promising results. Experimental flux decay test results are presented, which, together with standstill torque measurements, validate the finite-element model. Advanced iron loss computation by finite-element analysis indicates moderate core loss, although high air-gap magnetic flux density and current harmonics occur as a natural behavior of a BLDC machine. Electrical and mechanical parameter identification is followed by the development of a circuit model based on FEM imported data for parameters and by a four-quadrant control strategy proposal. Running experiments (motoring and generating) with speed-reversal and field-weakening modes using a DSpace platform, which drives three three-phase inverters that power a star-connected six-phase BLDC multiphase reluctance machine are presented, thus showing operation with a reduced number of switches in the inverter. [ABSTRACT FROM AUTHOR]

In this paper, a double salient exterior rotor permanent magnet machine is proposed and analyzed. This machine introduces the use of permanent magnet (PM) into a switched reluctance machine and has the same envelope as that of Toyota Prius third-generation (P3G) 60 kW interior PM synchronous machine (IPMSM). Simulation results show that the continuous torque and peak torque of the proposed machine are 97% and 30.4% more than that of P3G IPMSM under the same current density. [ABSTRACT FROM PUBLISHER]

In this paper, a new technique for estimation of airgap length in magnetically levitated systems (MagLev) is introduced. The proposed method makes use of the embedded airgap information in the inductance of an active phase in a hybrid MagLev system. Terminal measurements are used along with the phase voltage equation to estimate airgap length by the virtue of an existing one-to-one correspondence between inductance and airgap length. Sensitivity analysis will be carried out to illustrate the impact of changes in MagLev's geometry and current sensor resolution on the accuracy of the proposed method. Based on experimental results, it will be shown that the proposed sensorless method performs well both at standstill and moving conditions. [ABSTRACT FROM AUTHOR]

Permanent magnet synchronous machines (PMSM) are widely used in industrial applications. Partial demagnetization and static eccentricity are among common faults in PMSM. These faults will alter the acoustic behavior and torque pulsation by a significant margin. In this paper, results of a thorough investigation on the impact of these faults on the force distribution, vibration, and acoustic behavior of the PMSM is presented. Our force analysis is based on the field reconstruction method which is a very efficient technique for multi-physics field problems in electromechanical energy converters. [ABSTRACT FROM PUBLISHER]

This paper aims to describe a numerical modeling process for estimating the electromagnetic noise radiated from a permanent magnet synchronous machines. The original contributions concern the inclusion of a complete evaluation of the electromagnetic forces acting on the stator teeth, a complete 3-D structural finite-element model and a point wise approximation for acoustic calculation. Structural and acoustic responses of the targeted machine have been derived and validated using experiments. Superior precision of the proposed method has been substantiated through experiments. [ABSTRACT FROM AUTHOR]

In this paper, a new switched reluctance machine with a double-stator configuration (DSSRM) is introduced. The proposed design is based on optimization of the motional forces, which leads to a high-grade electromechanical energy conversion process. A local examination of the force densities within and throughout a conventional switched reluctance machine (SRM) shows that the majority of the force produced is in the radial direction and does not contribute to motion. If the normal forces happen to be in the direction of motion, a larger motional force profile for SRM is yield. Based on these guidelines, a new SRM (DSSRM) is proposed. To compare energy conversion efficiency of DSSRM with that of the conventional SRM, a finite element model is constructed. An experimental prototype of the proposed machine is developed, and the phase inductance is measured. The results of our investigations indicate that the proposed geometry offers superior performance in terms of higher power density and higher percentage of the motional forces. [ABSTRACT FROM AUTHOR]

Doubly fed induction generator is attracting attention among options in distributed wind energy harvest. Traditional design and analysis of doubly fed induction generator (DFIG) dominantly rely on lump-parameters and finite-element models. Although finite-element analysis (FEA) method is available, the computational time limits its application in iterative optimal design practices. This paper is based on the use of field reconstruction method (FRM) which can greatly reduce the computation cost, whereas maintaining acceptable accuracy. In order to conduct efficiency optimization, the procedure to calculate flux density and core losses are described. Finally, an optimal design method of DFIG towards maximum annual energy production in a given area with available wind speed information is presented. [ABSTRACT FROM AUTHOR]

In recent research, a field reconstruction (FR) technique was developed to enable more efficient evaluation of the magnetic fields and forces within induction machines. By using the FR, the results of two finite-element (FE) solutions (in which stator current is used as the input to the FE model) are used to establish basis functions for the flux densities in the air gap of the machine. The basis functions are then used to predict the magnetic fields and forces under arbitrary stator excitation. In this paper, the technique is enhanced to enable modeling with stator voltage (rather than stator current) as the model input. This enables a more convenient coupling of the FR model to external circuit components to model overall system performance. [ABSTRACT FROM AUTHOR]

Traditional analysis and design of induction machines have been largely based upon lumped-parameter models. An alternative tool used for field-based evaluations of an induction machine is the finite-element method. Although useful, its computational complexity limits its use as a design tool. In this paper, a field reconstruction (FR) method for induction machine simulation is introduced. The FR method utilizes a small number of finite-element evaluations to establish basis functions of normal and tangential flux densities. The basis functions are then used to estimate the magnetic field under arbitrary stator excitation. Using such a tool, evaluation of fields and forces produced by a machine under alternative excitation strategies can be explored efficiently. Moreover, alternative field-based derivation of stator/rotor excitation control can be explored. [ABSTRACT FROM AUTHOR]

Traditional analysis of permanent magnet synchronous machines has focused upon establishing a relationship between the quadrature (q) and direct (d) axis stator current (or voltage) and the electromagnetic force created to establish rotation (torque). In this paper, an alternative analysis of electromagnetic force production is considered. Specifically, the influences of q- and d-axis stator current on both the radial and tangential components of the airgap flux densities are first evaluated. Using a Maxwell stress tensor approach, the fields are then used to evaluate both the radial and tangential component of force density created in the airgap of the machine. From this perspective several interesting observations are made. First, it is shown that the d-axis current has zero influence on the average tangential force (torque), as predicted using traditional analysis, but it has a significant influence on the average radial component of force. Second, it is shown that the q-axis current contributes to both the average radial and average tangential components of force. Interestingly, it is also shown that under standard operating conditions, the average radial force far exceeds that of the average tangential component of force. Therefore, one can conclude that the magnetic fields established create a significant component of force in a direction that cannot produce torque. [ABSTRACT FROM AUTHOR]

Fault tolerance is a critical attribute in automotive electrical and propulsion systems. In this paper, a control scheme is presented that allows an induction motor drive system to operate in the event of multiple sensor failures. Automatic diagnosis of sensor fault and recovery is performed and used to reconfigure the drive system controls to achieve the best performance in lieu of component degradation. This approach couples a new digital delta-hysteresis regulation scheme with a model reference adaptive system scheme in order to provide fault tolerance for both phase-current and rotor position (speed) sensors. Simulation and experimental results are provided to show the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Development of a reliable, smooth, and precise position sensorless startup routine is an integral part of the switched reluctance machine (SRM) control. The proposed sensorless startup method presented in this paper presents high grade performance and does not require additional hardware or memory. Further, the proposed sensorless technique is extended to rotating shaft conditions. These capabilities are highly demanded by automotive applications such as starter/alternator and electric power steering systems. An assessment of the impact of motor parameters and diagnostic signal measurement on the quality of the sensorless startup method is also included. This will help practicing engineers to make judicious selections for implementation of the proposed technique. Experimental and theoretical results are included to validate our claims. [ABSTRACT FROM AUTHOR]

Current vehicle architectures utilize belt driven components such as the coolant pump, air-conditioner, power steering pump, etc. However, the trend toward more electric vehicles requires electromechanical energy conversion devices to replace these inefficient mechanical components. It is essential that electrical machines used in automotive applications to be compatible with the corresponding mechanical and electrical terminals. Furthermore, replacement of belt driven components with electrical drives should be performed as efficient and cost effective as possible. Bipolar switched reluctance machines (SRM) are both cost effective and very robust to the effects of temperature variation. They also offer a very wide speed range and an excellent mechanical integrity, which optimally suits a range of automotive applications including electric propulsion. This paper presents a detailed investigation of the performance indices for bipolar SRM drives. Using a Maxwell stress method, variations of radial and tangential force components due to saliency of the machine and saturation have been studied. Access to distribution of the force components acting on the rotor and stator enables us to provide a more accurate picture of the torque generation and vibration in this family of electric machines. Furthermore, distribution of magnetic forces under multiphase excitation has been studied in detail. Our findings show that bipolar excitation of SRM phases, resulting in a short flux path magnetic circuit, favors its efficiency and power quality while generating higher torque with less pulsation. This is a significant improvement, particularly for automotive applications where the difference in the required number of power electronics components can be justified. An experimental, 2-kW, 42-V, 8/6 SRM drive which has been designed and manufactured in our energy system laboratory was targeted for this study. In addition to our extensive finite-element (FE) analysis, experimental results have been provided to prove theoretical claims. [ABSTRACT FROM AUTHOR]

Calculates the switched reluctance motor (SRM) optimal control parameters which maximize torque per ampere using an SRM model. Magnetic nonlinearity of the SRM; Torque generation in SRM; Restriction imposed on the drive performance of the model; Analysis of the optimal control scheme.

In this article, a simplified 3D magneto-thermal model to study the temperature distribution over the housing of a Switched Reluctance Machine (SRM) is proposed. The main objective of such model is to study the temperature distribution profile on the body of the machine under various working conditions in order to introduce a temperature based signature to develop condition monitoring procedures. The analysis of fluid flow and heat transfer inside the SRM supports the hypothesis that the effect of turbulent flow of the fluid and the complex heat transfer phenomenon of the rotating parts can be simplified to a heat flux boundary condition representation of the heat loss. The accuracy of the model is validated through simulation and experimental results on a prototype SRM. The developed simplified model can be used as for prediction of temperature profile on SRM surface, well suited for fault diagnosis in SRM. The proposed methodology can be modified applied in developing a thermal model for other types of electric machines. [ABSTRACT FROM AUTHOR]

Despite many efforts being devoted to simplify the analysis of Synchronous Reluctance Motors (SynRM), the use of analytical methods to calculate torque ripple in these machines remains an ongoing challenge. In this paper, the electromagnetic characteristics of a SynRM are obtained using the combined conformal mapping (CM) and magnetic equivalent circuit (MEC) method. The proposed combination makes it possible to take into account the effects of stator slots and rotor flux barriers (FBs) in modeling of the radial and tangential field components. This is accomplished by introducing virtual currents in the CM model to account for rotor potential drops due to the presence of FBs. These potential drops are calculated using the MEC model. Once specified, the field components are used to calculate the SynRM torque with three FBs. Finally, the accuracy of the proposed method is validated by comparison with finite element analysis results. [ABSTRACT FROM AUTHOR]

With the development of high-temperature wide bandgap power semiconductors, such as SiC MOSFET and GaN HEMT, it becomes possible to integrate the power converter directly into motors. However, the leakage magnetic flux in the motor may cause interference with the operation of the electronic circuit. In this article, the electromagnetic compatibility of the power converter integrated in an induction motor is investigated. The simulation shows that the leakage magnetic flux of the end-winding will penetrate into the nearby area, and it will cause interference with the Hall-effect current sensors if the power converter is mounted in the space between the motor end cap and the end-winding. A prototype of the GaN-HEMT-based power converter is built and integrated into a 3-hp induction motor. The leakage magnetic flux is scanned by the linear Hall-effect sensors and the measured result is aligned with the finite-element simulation. [ABSTRACT FROM AUTHOR]

Vibration and acoustic noise are considered as major factors preventing the widespread use of switched reluctance motor (SRM) drives in industrial and commercial applications. In this paper, a new active vibration cancellation strategy for radial vibration is proposed based on the optimal current switching instants. The mechanical impulse response method has been used to estimate the radial vibration of the stator and an optimization routine was developed to define the optimal instants for phase current switching in such a way that the resulting vibration would cancel the vibration caused by prior switching. Experimental verification was conducted on an 8/6 SRM and the results show significant reduction in the stator radial vibration which in turn contributes to reduction of acoustic noise. [ABSTRACT FROM AUTHOR]

Vibration and acoustic noise in switched reluctance motor (SRM) drives have been investigated and addressed frequently. However, the focus of most the paper is on vibration of the stator frame due to radial electromagnetic forces acting on the stator teeth. In this paper, a comprehensive vibration analysis for a SRM assembly using finite element (FE) method is conducted, which considers the stator and rotor vibrations due to radial electromagnetic force as well as the effect of mechanical coupling on the vibration between the stator and rotor. First, an experimental modal test was performed to extract modal parameters and to observe the coupling effect. The parameters were then used to adjust and validate the FE model that was used to obtain transfer functions for vibration characterization. Using the frequency domain representation of the radial magnetic force vector and the calculated transfer functions, radial and tangential vibration components have been predicted. [ABSTRACT FROM AUTHOR]

In this study, a combined ON/OFF and conformal mapping method is applied to the permanent magnet shape optimisation of the surface-mounted permanent magnet synchronous motor (SPMSM). The magnet shape has a profound impact on the cogging torque and torque profile of the SPMSM. The proposed method is based on the combination of the conformal mapping and ON/OFF methods, which can reduce computation time significantly as compared with methods that are based on the finite-element method (FEM). For the optimisation process, genetic algorithms are used and applied to three cases. Finally, the FEM is used to verify the magnetic model and characteristics of the optimised machine. [ABSTRACT FROM AUTHOR]

In this study, a combined ON/OFF and conformal mapping method is applied to the permanent magnet shape optimisation of the surface‐mounted permanent magnet synchronous[AQ ID=Q2] motor (SPMSM). The magnet shape has a profound impact on the cogging torque and torque profile of the SPMSM. The proposed method is based on the combination of the conformal mapping and ON/OFF methods, which can reduce computation time significantly as compared with methods that are based on the finite‐element method (FEM). For the optimisation process, genetic algorithms are used and applied to three cases. Finally, the FEM is used to verify the magnetic model and characteristics of the optimised machine. [ABSTRACT FROM AUTHOR]