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Three-phase wireless power transfer (WPT) systems have compact coil structures, canceled triplen harmonics, and less dc-link current ripple, which are suitable for wireless electric vehicle (EV) charging systems. Most three-phase WPT systems are based on two-level inverters. Alternately, three-level inverters have the potential to further promote the performance of EV chargers by reducing electromagnetic interference (EMI) and the voltage stress of power switches. However, the unbalance of the neutral point voltage is a problem for traditional three-level inverters. This paper proposes a three-level three-phase WPT system for EV wireless charging, which is based on a T-type neutral point clamp (TNPC) inverter. The modeling, coil structure, and switching pattern of the proposed system are analyzed in detail. Furthermore, a novel output regulation method based on vector control is proposed for the WPT system. Also, a neutral point voltage balance strategy is proposed to enhance the reliability of the three-level inverter. Both simulations and an experimental prototype based on SIC-MOSFET are given to verify the effectiveness of the proposed three-phase WPT system and control method.

In permanent-magnet synchronous motor (PMSM), the winding current consists of different orders of harmonics due to the manufacture error, deadtime, and disturbances. This article proposes a winding current harmonic suppression method for PMSM by reducing the dominant fifth- and seventh-order current ripples. First, with reference frame transformation, the fifth- and seventh-order current ripples convert to sixth-order ripples in the synchronous reference frame (SRF). Then, with further transformation, these sixth-order ripples turn to dc signals. Next, the type-II Chebyshev filter is designed to extract these dc signals. Also, the proportional–integral (PI) controller is adopted to generate the current harmonic control voltage, which is setting the dc current harmonic signals reference to be zero. Finally, the current harmonic control voltage is compensated to the voltage reference in the SRF. Both the simulation and experimental results are presented to verify the effectiveness of the proposed method.

Monitoring power quality (PQ) in microgrids is gaining increasing attention in recent years due to the popularity of microgrids and PQ disturbances caused by renewable energies. Many techniques based on artificial neural networks (ANNs) are proposed for monitoring the PQ with no need to pre-set thresholds. However, the necessity of retraining the ANN is a big problem when the electrical parameters vary. This article proposes a new approach to detect and classify the PQ disturbances accurately in multimicrogrids based on electromagnetic sensing and portability-enhanced ANN. The proposed ANN-based approach avoids the retraining of weights, when the voltage, current, and frequency varies with microgrids. Two steps are critical for achieving the portability of the ANN in various microgrids, which are pre-normalization and using the same maximum and minimum feature vectors for feature matrix normalization. Meanwhile, the electromagnetic sensing facilitates non-intrusive monitoring and easy installation. The high accuracy of simulation and experimental results in various scenarios validate the effectiveness and efficiency of this portable and non-invasive approach for monitoring PQ in multimicrogrids without retraining ANN.

The permanent-magnet Vernier (PMV) machine has been welcomed for direct-drive applications recently. Also, the fault tolerance is critical for special machine design in hostile conditions. This article proposes an efficient PMV machine with the modular winding configuration, which takes the fault-tolerant capability into account, especially the open-circuit fault. With the modular winding design, the better isolation between phases and modules can be obtained instead of dividing the stator core into segments. Meanwhile, the high efficiency needs to be guaranteed under both normal and partial-module operations. Therefore, the machine design, basic characteristics, and the fault-tolerant operation are performed and verified. Finally, the efficiency performances under normal and modular operations are analyzed and compared, which demonstrates the validity of the proposed idea and relevant considerations.

This article proposes the dc-biased operation of a new double-stator hybrid flux switching permanent-magnet (DSH-FSPM) machine. Through directly injecting the dc current into the armature windings, the dc-biased strategy contributes both the flux-enhancing (FE) and flux-weakening (FW) capabilities into the proposed machine design. First, the machine optimization is carried out to obtain the optimal dc-biased current, with the criteria of the torque performances. Then, when compared with the pure-armature-current and max-dc-current strategies, the optimal dc-biased operation increases the average steady torque by 41.3% and 65.5%, respectively. Moreover, the high torque-speed capability is analyzed with the cooperation of the FE and FW operating modes. With 2 A FW dc-biased current injection, the rotational speed is extended to two rated speed with the half-rate output torque. Under the max-dc-current FW operation, the speed can maximumly expand to six rated speed. Consequently, the wide speed range is realized with the integration of the FE and FW modes. Also, the loss and efficiency analysis are carried out based on the whole machine speed range. The simulations are performed to verify the feasibility of the proposed dc-biased DSH-FSPM machine.

Power split system is the key power transmission component in hybrid electric vehicles (HEVs). This paper presents a new consequent-pole inserted permanent magnet (PM) double-rotor machine., which is suitable as the power split system for HEV. The key is to insert the interior radical magnetized PM with the same polarity into the rotor's iron core., so the mechanical structure of the proposed machine is more robust. Also., the working principle is analyzed., and the structure is optimized. In addition., the performances of the conventional machine and proposed type are quantitatively compared. The result shows that proposed machine has more advantages to be applied for the power split system in HEVs.

In this paper, a direct grid-connected servo system without de-link capacitor is proposed for multi-phase machines. First, the space current vector control and field oriented control are performed for the direct grid-connected multi-phase servo system. Second, the vector coordination under non-constant de-link voltage is introduced to ensure the safe current commutation. Moreover, the torque and harmonic current control are implemented independently with vector space decomposition. Finally, the experimental results are given to verify the effectiveness and validity of the proposed servo system.

Smart living is a trending and connected lifestyle that envisions efficient and sustainable energy utilization, stable and reliable power supply, intelligent and coordinated transportation and mobility, and personalized and cost-effective healthcare. Its realization needs the Internet of Things (IoT). IoT is a compelling platform connecting trillions of sensors and collecting data for connectivity and analytics. It is more advanced than traditional monitoring systems where limited sensors and wired communication can merely collect fragmented data in the application domains. Spintronic sensors with the superb measuring ability and multiple unique advantages can be one of the critical sensing devices supporting the IoT and enabling smart living. In this paper, we review successful applications of individual spintronic sensors in electrical current sensing, transmission and distribution lines monitoring, vehicle detection, and biodetection that can help to fulfill the promises of smart living in energy management, power delivery, transport, and healthcare. The wireless spintronic sensor networks (WSSNs) working at the massive interconnected network level are proposed and illustrated to provide pervasive monitoring systems, which facilitate the intelligent surveillance and management over building, power grid, transport, and healthcare. The database of collected information will be of great use to policy making in public services and city planning. This paper provides insights for realizing smart living through the integration of IoT with spintronic sensor technology.

This paper presents the design and optimization procedure of a novel mechanical-offset complementary-stator flux-reversal (MOCS-FRPM) machine. First, based on the original topologies, the pole-pair and flux modulation pole optimizations contribute to the high power density, efficiency, and larger torque capacity for the machine design. Second, based on the 2-D optimization results, the 3-D mechanical-offset structures are adopted for the torque ripple suppression. In fact, compared with the 3-D non-offset machine, the rotor mechanical-offset topology possesses the better torque performance, which can decrease the torque ripple by 34.6%, and with a slight 6.4% reduction of the torque average. Thus, through the proposed optimization procedure, the new complementary-stator machine accommodates the merits of the large torque capacity, low torque ripple, high efficiency, and high reliability. Also, the artful incorporation of the 2-D and 3-D optimizations leads to the reduced computation time and higher optimization efficiency.

This paper proposes the design and multi-mode operation of a new double-stator toroidal-winding permanent-magnet vernier (DSTW-PMV) machine, which is for the wind-photovoltaic (W-PV) hybrid generation system. In the W-PV system, the wind and PV power are complementary with each other for power variation reduction. Through the multi-mode operation, the output voltage of the machine can be stabilized with high continuity under different rotational speeds to solve the inherently indeterminate wind speed problem and further improve the power smoothness of the whole W-PV system. First, the machine optimization is carried out to obtain the optimal pole-pair combination and geometrical topology for the proposed machine. Second, based on the optimal topology, the multi-mode operation principle of the output voltage adjustment is illustrated. By utilizing the diversities of the toroidal winding configurations and terminal connection strategies, the proposed machine accommodates 54 operating modes with different output voltages under rated speed. Accordingly, under the rated output voltage, the machine speed can be extended to three rated speed with high continuity. Furthermore, some modes generate the rated output voltage with identical speed, which contributes to the high redundancy and high operating efficiency. Hence, with the multi-mode operation and the auxiliary of the PV power, the whole power generation system accommodates the higher flexibility, stability, reliability, and efficiency.

Noncontact monitoring technique of mechanical and electrical states is increasingly attractive for the overhead transmission system. This paper proposes a new technique to detect the tower inclination and transmission line sag, and measure transmission current simultaneously. The key of this technique is to use the ground magnetoresistive (MR) sensor to measure the magnetic flux density along the center line from the three-phase transmission lines. Moreover, the magnetic field (MF) calculation formulas for a tilted tower are given in this paper. Finally, with MF calculation formulas, an algorithm based on artificial immune system (AIS) is applied to estimate the transmission line sag and tower tilt angles, and reconstruct currents. Model simulations of an overhead transmission system are carried out to verify the idea. The simulation results validate the feasibility of this noncontact approach to estimate mechanical parameters and reconstruct electrical parameters for overhead transmission system.

Electric continuously variable transmission (e-CVT) device is a key component in hybrid electric vehicles (HEVs), which serves to perform the energy transmission among the initial combustion engine, battery, and output shaft. This paper presents a novel consequent-pole PM magnetic-geared double-rotor machine (CPDRM) that utilizes the magnetic gearing effect to transmit the power with a high efficiency. The artistry of CPDRM is to insert a dc winding within the center of the stator on the circumferential direction. Therefore, the machine can extend the constant-power region by changing the current direction and amplitude of dc windings. Meanwhile, the flux density within the air gap is changed accordingly. Then, the working principle of CPDRM and the flux change process are illustrated by employing the magnetic circuit method. Finally, a finite-element method model is constructed to verify the performances of the CPDRM under different operating modes. The result shows that the proposed machine has an excellent flux-weakening ability, and it can serve as a suitable candidate as an e-CVT component for HEVs.

Power allocation is important for dynamic dual-pickup wireless charging system of electric vehicles (EVs). The existing power allocation methods of wireless power transfer technology mainly focus on allocating the power to loads according to the needs with different resonant frequencies. However, the issues of inaccuracy and low power are still not well solved by the existing methods. In addition, the control strategies of existing methods are complex and difficult to implement in practical situations. In this paper, a new power allocation method is proposed, which can dynamically and precisely allocate power to loads. Moreover, the dynamic mutual inductance estimation and the power ratio change between loads are also investigated. In addition, this method has no need to use additional circuits for the receiving coil. Thus, it is convenient to implement in the dual-pickup wireless charging system of EVs. Experimental results have well verified the correctness of the proposed dynamic mutual inductance estimation and power allocation method.

This paper proposes dual-stator permanent magnet Vernier (DS-PMV) machines for direct-drive applications. Also, the quantitative comparison of DS-PMV machines is carried out in terms of no-load performance and output torque characteristic. First, the operation principle is elaborated. Then, the theoretical expressions of air-gap magnetic fields are derived through the magnetic circuit approach. Moreover, the basic machine performances with different pole–slot configurations are quantitatively compared. The corresponding demonstration results are given, which verify that the designs without auxiliary teeth tend to have lower amplitudes of back electromotive force (EMF) harmonics, higher rated average torque, and lower torque ripple.

The wirelessly transferred power as well as charging efficiency will significantly drop due to the large misalignment between the transmitting coil and receiving coil for roadway electric vehicles (EVs). A low-cost and reliable misalignment-tolerant wireless charging technique is indispensable for the rapid commercialization of wireless EV charging. This paper presents a technique to achieve the misalignment-tolerant wireless charging for the dynamic wireless charging (DWC) system by means of a tunneling magnetoresistive (TMR) sensor array as well as the easy-to-fabricate receiving coils. The TMR sensor array provides the coil-misalignment position by measuring the magnetic field component generated from the transmitting coil. The corresponding receiving coils are selected to be in resonance according to the measured coil-misalignment positions. In this paper, a sensor array composed of 29 uniaxial TMR sensors was utilized to measure the magnetic field component. This effectiveness of the proposed technique has been validated by both the finite-element method (FEM) simulations and laboratory experiments. The experimental results demonstrated that the proposed misalignment-tolerant wireless charging system can operate in a relatively wide misalignment range of ±120 mm with charging efficiency higher than 76.2%.

This paper proposes and implements a new move-and-charge (MAC) system for automatic guided vehicles (AGVs), which not only performs wireless charging, but also automatically navigates the AGV without using guiding sensors. The key is to make use of the dc–dc converter to maintain the equivalent load resistance and then detect the charging current variation to conduct the desired traction under constant ac input current for the rail transmitter. In order to avoid frequent corrections of the forward direction and dc–dc converter regulation, both the straight rail and turning rail conditions are analyzed to determine the threshold value of the charging current. Without any misalignment, its transmission efficiency can reach up to 83% and the traction allowance can achieve up to 30 mm under the transmission distance of 80 mm. Both the finite-element analysis and experimental results are given to verify the validity of the proposed MAC AGV system.

Due to high land prices in the metropolitans, such as Hong Kong, Tokyo and New York, high-rise buildings are mushrooming one after another. The conventional vertical elevators in multi-level or low-rise building, which usually adopt rotational electric motors plus hoist cables with counterweights, are no longer applicable. The cable for hoisting elevators have the strength and stability problems as it gets longer and longer [1], [2]. For solving these problems, a ropeless elevator system with self-propelled cars is proposed and testified. This system adopts the linear motor to drive the elevator car and omits the counterweight and cable [3], [4]. Thus, the efficiency and operation performances are dramatically improved. Moreover, areas of the elevator hoistway can be reduced [5]. According to the requirements, linear motors for ropeless elevators need to satisfy the following features: high power density, high force density, high reliability, high ratio of payload to self-weight and low force ripple. To achieve the above features, dual permanent magnet (PM) linear motors with fault-tolerant teeth (FTT) are good candidates. When the elevator car size is fixed, one way to further increase the force density with the same current density is to adopt the dual-PM structure [6]. Thus, in this paper, four dual-PM linear motors are proposed and compared for the application of ropeless elevator system.

This paper proposes a new double-stator magnetless vernier (DSMV) machine for direct-drive robotics. By artfully incorporating the double-stator structure, vernier configuration and dc excitation together, this DSMV machine yields the merits of the flux control capability, low-speed operation, high torque output, free maintenance, and high cost-effectiveness. Also, the optimizations of the rotor-teeth arc angle, stator-teeth arc angle, and current phase angle are carried out for the improvement of torque performance. In this way, the torque ripple of the machine is significantly reduced up to a tiny value of 3.67%. Moreover, the rational dc current range and the rotational speed range are obtained through the performance analysis with flux regulation. In addition, the comparison is performed with the conventional surface-mounted permanent-magnet machine. Therefore, the proposed machine shows the distinct features and is fit for the special application. Finally, both theoretical derivation and simulation are given for the validation of the machine design.

This paper presents an approach to detect the lateral coil misalignment for the dynamic wireless charging system using a tunneling magnetoresistive (TMR) sensor array. The component of the magnetic field generated from the transmitting coil can directly provide the information of the coil misalignment between transmitting and receiving coils. A sensor array composed of 15 uniaxial TMR sensors was implemented to measure the vector magnetic field for detecting the coil misalignment. Both 3-D finite-element method modeling and experimental results over a relatively large misalignment range were presented to substantiate the effectiveness and feasibility of the proposed approach.

This paper proposes a new electric magnetic-geared (EMG) machine, which artfully incorporates the magnetic gear into an outer-rotor inserted permanent-magnet (PM) machine, purposely for electric unmanned aerial vehicle (e-UAV) application. The proposed EMG machine artfully shares the sandwiched-rotor for both the PM machine and the magnetic gear. As a result, the proposed machine can run in the high speed and high power for propelling the e-UAV. The design details, operation principles, static characteristics, and machine performances, as well as the propulsion performances of the proposed machine, are elaborated and discussed. The finite-element method is utilized to verify the validity of the machine design and performances, with emphasis on the e-UAV application.

This paper proposes and implements the concept of time-division multiplexing (TDM) wireless power transfer (WPT) for separately excited dc motor drives. Essentially, the proposed WPT system has only one transmitter that can transfer power to multiple receivers simultaneously while the power transfer to individual receivers can be independently controlled. Thus, the armature and field currents of the separately excited dc motor can be independently controlled, hence achieving the desired constant torque operation and constant power operation. The key is to make use of the TDM scheme to simultaneously transfer powers to both the armature and field windings. Meanwhile, the burst firing control method is incorporated to independently regulate the power flows to the armature and field windings at the resonant frequency, hence retaining the maximum power transfer efficiency. Both finite element analysis and experimentation are given to verify the validity of the proposed system.

In order to fully utilize the high-energy nature of permanent magnet (PM) material, the stator-PM structure and the mover-PM structure of linear machines are integrated into one doubly salient PM machine topology, leading to a new class of doubly salient dual-PM linear machines. In essence, PMs are mounted on both the stator and mover iron cores while avoiding magnetic saturation, hence offering the high force density and high power density. Meanwhile, it consists of a fault-tolerant tooth stator and a consequent-pole mover, which can provide the fault-tolerant capability and exert the salient effect, respectively. By using finite-element analysis, the proposed machine is optimized for application to regenerative shock absorbers which can provide on-board renewable energy harvesting in vehicles. The machine performances are analyzed and quantitatively compared with that of its counterparts including the stator-PM linear machine and the mover-PM linear machine. Moreover, both the flat and tubular morphologies of the proposed machine are quantitatively compared and discussed.

Fault tolerance is a key factor for motor driving systems in electric vehicles. To realize the high fault-tolerance under short-circuit, open-circuit, and demagnetization fault, this paper proposes and investigates a new six-phase fault-tolerant hybrid-excitation motor. First, the single concentrated armature winding is adopted to achieve electrical, magnetic, thermal, and physical separations. The unequal teeth width and the asymmetric air-gap length are designed and optimized to reduce torque ripple and distortion of phase back EMF. Furthermore, the field windings are designed to provide magnetization under demagnetization fault. In addition, the motor is designed with the simple structure and no sliding contacts, as well as robust rotor with no windings. Moreover, the topology and operating principles of the proposed motor are analyzed; the characteristics of the proposed motor under healthy and fault conditions are investigated using finite-element analysis. Finally, the calculation results are given to verify the validity of the high fault tolerance for the proposed motor.

This paper presents a new hybrid-structure machine, which possesses the distinct merit of multimode fault-tolerant operation for driving Mars Rover. Namely, the proposed machine is designed with three operation modes, including Mode I for the normal operation, Mode II for the remedial field-excited operation, and Mode III for the remedial rotor operation. To obtain these operation modes, the machine design adopts the outer rotor structure with a segmented-iron ring and a special teeth-split inner stator. In this way, the proposed machine is capable of providing the desired torque output at low speeds under the normal or fault situations. Both the machine design principle and the corresponding results are given to verify the validity of the idea. Furthermore, the different combinations of the torque outputs under different operation modes for four-wheel motors of Mars Rover are analyzed and discussed.

This paper proposes a combined numerical and analytical approach for magnetic vibration analysis of a new dc-excited multitoothed switched reluctance (MSR) machine. First, the machine design is artfully to incorporate the dc-excited winding into the MSR topology, hence breeding a new flux controllable, high-torque, low-torque ripple, and doubly salient magnetless machine. Then, the finite-element-method is used to calculate the machine force and torque. A series of analytical equations are formulated to calculate the magnetic vibration parameters of the proposed machine. The analysis process and the corresponding results are given to verify the validity of the proposed approach for magnetic vibration analysis of the new machine.

In this paper, the concept of dc-field excitation is newly incorporated into the axial-flux doubly salient (AF-DS) machine, leading to create the new magnetless AF-DSDC machine. With the external field excitation, the proposed machine not only can enjoy its improved torque density, but also the flux-weakening capability for the wide-speed range operation. With these characteristics, the AF-DSDC is favorable for the in-wheel direct drive application. In particular, the proposed machine is designed and compared based on the requirement of a typical passenger electric vehicle. To have a better illustration, a radial-flux DSDC machine is also designed under the fair environment. The corresponding performances of both machines are analyzed by using the 2-D and 3-D finite element method.

This paper implements the new design structure, so-called the mechanical offset (MO) into the double-stator multitoothed switched reluctance (DS-MSR) machine to form the new MO-DS-MSR machine. The major distinction of the MO structure is to purposely mismatch the outer and inner rotor teeth with a conjugated angle. With the MO structure, the outer and the inner torque components can be compensated with each other, hence minimizing the resultant torque ripple. By employing the finite element analysis, the characteristics and performances of the proposed machines are analyzed and compared.

This paper presents the quantitative analysis for the optimal design of wireless power transmission (WPT) systems based on magnetic resonant coupling (MRC) mechanism. In this paper, the exemplified MRC-based WPT system adopts the series-series topology and one resonant coil, which shows that the energy efficiency and transferred power are both significantly affected by the mutual inductance of the primary-resonant coils and the resonant-secondary coils. In addition, the simulated and experimental results are both provided to illustrate the influence of the mutual inductance on the performance of MRC-based WPT systems regulating the relative displacement among coils. Thus, this quantitative analysis can offer the significant theoretical and experimental basis for the optimal design of MRC-based WPT systems in various application fields.

This paper quantitatively compares three advanced magnetless machines, namely the switched reluctance (SR) machine, double-stator SR (DS-SR) machine and DS multitoothed SR (DS-MSR) machine. The DS-SR machine is particularly favorable for low-torque highspeed operation while the DS-MSR machine is desirable for high-torque low-speed operation. Because of more effective power transfer by using two stators, the two DS machines achieve better performances than the single-stator counterpart. All machine performances are analyzed by using the time-stepping finite element method.

The permanent magnet linear vernier (PMLV) machine is becoming attractive for low-speed and direct-drive applications. Due to its vernier structure and multipole configuration, the flux leakage especially the tooth-tip flux leakage is severe. In order to analyze its leakage flux, the magnetic equivalent network of the PMLV machine is applied for analytical modeling. During modeling, the fringing effect in the air-gap is taken into consideration. The key for the flux leakage calculation is to calculate the permeances at different tooth positions. Finally, in order to evaluate the proposed analytical model of the PMLV machine, the finite element method is employed for numerical calculation. The comparison between the analytical and numerical results verifies that the proposed analytical modeling approach is valid and accurate.

In this paper, the concept of double stators and the concept of magnetic gears are artfully integrated to form a novel class of machines. By utilizing the modulation-ring structure, the proposed machines can modulate the high-speed rotating armature field of the stators to match the low-speed rotating permanent-magnet (PM) field of the rotor. Hence, the machines readily achieve the low-speed high-torque merit. In addition, the fractional-slot structure can be adopted for the inner-stator design to remove the modulation-ring of the inner stator. Two possible machine structures are discussed and compared. Their characteristics and performances are calculated by using the time-stepping finite-element-method. The results well verify the validity of the proposed machine design.

The permanent magnet (PM) dual-memory machine incorporates the concept of PM memory machines and PM hybrid machines, hence offering the flexible flux-tuning and flux-mnemonic function. It employs the aluminum-nickel-cobalt (Al-Ni-Co) and neodymium-iron-boron (Nd-Fe-B) PMs as a PM group embedded in each PM pole to complement each other. Thus, it inherently achieves the merit of high working temperature and high power density. Design principles of this new class of machines are devised and discussed. Both simulation and experimentation are given to demonstrate the validity of the proposed design principles.

By artfully integrating the vernier structure and the DC field winding together, a novel flux-controllable vernier permanent-magnet (FCVPM) machine is proposed, which has the merits of offering high torque output at low speed operation and the flux weakening control at high speed operation. The key is to use the flux modulation poles to modulate the high speed rotating field of the armature winding and the low speed rotating field of the PM rotor, thus achieving the gear effect for high torque output. Also, the DC field winding is specially incorporated into the stator embedded slots, which can effectively weaken the airgap flux density, thus realizing the flux weakening control at high speed operation. By using the time-stepping finite-element-method, the basic characteristics, low speed and high speed operation performances of the machine are analyzed, which verifies the validity of the machine design.

The permanent-magnet hybrid brushless (PMHB) motor adopts both DC field windings and PMs for excitation. It not only offers effective online flux control, but also flexible brushless DC (BLDC) or brushless AC (BLAC) operations. The key of this paper is to investigate two remedial strategies for fault-tolerant operations of the PMHB motor drive under open-circuit faults. First, by utilizing field excitation boosting, the reduced torque due to one phase loss can be remedied, the so-called remedial BLDC operation mode. Second, by reconstructing armature fields due to the healthy phase currents, the reduced torque can also be remedied, the so-called remedial BLAC operation mode. Finally, these two remedial operation modes are compared and verified by experimentation, hence confirming the validity of the proposed fault-tolerant PMHB motor drive.

This paper proposes a new outer-rotor permanent-magnet (PM) vernier machine for direct-drive wind power generation, which can offer low-speed operation to directly capture wind power, and enable high-speed rotating field design to maximize the power density. Compared with its mechanical gear counterpart, the proposed machine can eliminate the mechanical wear and tear as well as gear transmission loss, thus improving the generation reliability and efficiency. The key is to newly introduce the flux-modulation poles which can effectively modulate the high-speed rotating field of the armature windings and the low-speed rotating field of the PM outer rotor. By using the time-stepping finite-element method, the proposed machine can be accurately analyzed. Hence, its performances are quantitatively compared with other PM vernier machines, thus verifying its validity.

This paper proposes a new efficiency optimization approach for a new kind of permanent-magnet hybrid brushless (PMHB) machine. The key is to propose the self-searching control (SSC) for the PMHB machine in such a way that the input power at the given load and speed can be progressively minimized by tuning the dc field current. A loss analysis of the machine is given to justify the use of dc field current as the control parameter. Detailed experimental results confirm that the proposed approach can effectively accomplish the desired efficiency optimization.

This paper quantitatively compares two emerging stator-permanent-magnet (PM) machines, namely, the doubly salient PM and the PM hybrid brushless types. Both of them are attractive for electric vehicles and wind power generation. For comparison, both machines adopt the outer-rotor 36/24-pole topology and are designed based on the same peripheral dimensions. By using the circuit-field-torque time-stepping finite element analysis (CFT-TS-FEM), both steady-state and transient performances of the two machines are critically compared.

This paper proposes and implements a new 36/24-pole outer-rotor permanent magnet (PM) hybrid machine for directly coupled wind power generation. The key is to design the machine with hybridization of two excitations (PMs and dc field windings) in the double-layer stator so that it can provide effective flux control, hence realizing constant voltage output over wide ranges of speeds and loads. The machine design is illustrated by finite-element analysis and then verified by experimentation.

In this paper, a new chaotic pulse width modulation (PWM) scheme is proposed and implemented to reduce the conducted electromagnetic interference (EMI) in motor drives. The key is the use of logistic mapping to chaoize a frequency-modulated signal which then modulates the carrier frequency. Compared with the sinusoidal PWM and random PWM, the proposed scheme not only suppresses the peaky EMI, but also avoids the occurrence of low-order noises and mechanical resonance. Both simulation and experimental results are given to support the validity

In this paper, a new double-stator cup-rotor permanent-magnet machine is proposed and implemented for wind power generation. The design of unique double-stator configuration can improve the power density for easy installation, while the control of its winding connections can provide a constant output voltage over a wide range of wind speeds. The circuit-field-torque coupled time-stepping finite element method is utilized to analyze the proposed machine. Both analysis and experimental results are given to confirm the validity of the proposed machine

This paper proposes a novel in-wheel motor, which artfully integrates a magnetic gear into a permanent-magnet brushless (PMBL) DC motor so that they can share a common PM rotor, hence offering both high efficiency and high power density. Moreover, the low-speed requirement for direct driving and the high-speed requirement for compact motor design can be achieved simultaneously. A 2-kW 600/4400-rpm magnetic-geared outer-rotor PMBL DC motor is designed and analyzed, which is particularly suitable for battery-powered electric motorcycles

This paper presents a hybrid excited doubly salient (HEDS) machine, which can be used as the integrated starter-generator (ISG) for modern automobile and hybrid electric vehicles (HEVs). The key of the proposed machine is to incorporate both direct current (dc) field windings and permanent magnets (PMs) in the stator, hence, offering a compact arrangement of hybrid field excitations, while the rotor is simply composed of salient poles without windings or PMs. The air-gap flux can be strengthened or weakened with a reasonable dc field current so that the electromagnetic torque and induced electromotive force (EMF) can be effectively regulated. To predict the electromagnetic performances of the machine more accurately, a new transient cosimulation approach considering indirect field-circuit coupling is proposed. Experimental results on a prototype machine have been given to verify the technique. The method is not only more efficient and flexible, but also more accurate and stable, which can also be used in analyzing other electric machine and drive systems