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In this paper, a novel dual-rotor multiple-winding machine (DRMWM) is proposed for the continuous variable transmission (CVT) in hybrid electric vehicles (HEVs). First, a mathematical model of the proposed machine is constructed by using the harmonic modeling method (HMM). Then, on the basis of the magnetic field analysis, the operating principle of the DRMWM is deduced. By introducing multiple windings with two different working harmonics, namely the permanent magnet (PM) harmonics, and the magnetic gear (MG) harmonics, the proposed DRMWM can cope with various operating conditions of HEVs. To further obtain optimal performance, a finite element analysis (FEA) and multi-objective genetic algorithm II (MOGA-II) combined sequential optimization is carried out for the proposed DRMWM. The proposed optimization method is proven to be more computationally efficient compared to the global optimization method. Finally, a prototype is manufactured and tested in various operating modes. The results validate the simulation and analytical method predictions. Also, it proves that the proposed DRMWM is suitable to work as the CVT in HEVs.

This paper presents a novel magnetic-geared direct-drive machine (MGDM) with V-shaped permanent magnets (PMs) installed on its rotor. By extending the inner rotor shaft and connecting it to a prime motor, the torque and power density of the proposed MGDM is boosted. Additionally, compared with the conventional MGDM with surface-mounted PMs, the proposed MGDM with V-shaped PMs has a more robust rotor structure to cope with extreme operating conditions. The operating principle and structure requirement of this MGDM are first derived. Then, the geometrical parameters are optimized via a three-stage multi-objective optimization method to maximize output torque and efficiency and minimize torque ripple via the genetic algorithm and finite element analysis (FEA) combined optimization strategy. Furthermore, the proposed MGDM is artfully integrated into hybrid electric ships (HESs) to construct an onboard integrated power system (OB-IPS). Since the proposed system possesses various operating modes to cope with practical operating conditions, it enjoys a high systematic efficiency and good dynamic performance. Finally, a prototype is fabricated and tested with various operating modes by referring to the practical navigation cycle of a HES. The experimental results validate the feasibility of the proposed MGDM for being applied in HESs.

This article presents a high-fidelity analytical solution and a fast integrated optimization method for vernier machines. First, a harmonic modeling method (HMM) is adopted to obtain the magnetic field distribution of vernier machines. Particularly, the stator teeth of vernier machines are divided into several blocks to take account of the local magnetic saturation of soft-magnetic material. Then, the electromagnetic parameters, such as the average torque, torque ripple, and efficiency, can be calculated via the analytical model. Next, the proposed harmonic model is combined with the nondominated sorting genetic algorithm II (NSGA-II) to determine a multiobjective optimal design for the studied vernier machine. This integrated optimization method can save computation time, because the data interaction process between the finite-element analysis (FEA) software and the optimization software is eliminated. Finally, the performances of the optimal case are verified by both FEA and experiments with the prototype.

Recently, detecting the magnet defect fault in permanent magnet synchronous generators (PMSGs) is still challenging. The previous work mainly focuses on the phase current, back electromotive force, or searching coils. However, these methods are sometimes limited due to the machine configuration, being computationally complex, or even being intrusive to the system. This article presents a new method for the online detection of the magnet defect in a PMSG simultaneously. This method is based on the leakage flux outside the generator, which is noninvasive. In the practical application, the leakage flux is measured by magnetic sensors mounted outside a PMSG under various operating conditions. First, the external leakage flux is derived theoretically with the magnetic equivalent circuit when one defective rotor magnet exists in a PMSG. Then, the external leakage flux is proved to contain information about the health condition of inside magnets during the machine operation. Subsequently, the permanent magnet defect indicator $F_{\mathrm {ind}}$ is proposed for analyzing the condition of the rotor magnets in detail. Finally, both simulation and experiment results verify the efficacy of the proposed method.

Based on the electromagnetic-structural coupling analysis, this article proposes the comparative study of three double-stator interior- permanent magnet vernier (DS-IPMV) machines, including the spoke-PM, V-shape-PM (V-PM), and H-shape-PM (H-PM) rotor structures. DS cooperation strategies are adopted in the machine design for the performance improvement. Firstly, the rotor optimization of the proposed machines is carried out, with consideration of the tooth-slot cooperation between the rotor and stators. The electromagnetic- structural coupling-simulation is adopted for comprehensive evaluation. Then, the specific performance comparison is carried out, including the magnetic, structural and cost analysis. Consequently, the spoke-PMV machine accommodates the highest torque output, efficiency and cost-effectiveness; meanwhile, the V-PMV machine possesses the highest torque per PM volume with the better ripple performance. Accordingly, prototype experiments are carried out for the validation of the proposed machine design and comparison.

A Self-cleaning surface can efficaciously solve the problem of irreversible contamination buildup on filtration membranes. Photocatalytic membranes were fabricated via vacuum assisted layer-by-layer (LBL) self-assembly of 0D-2D Bi2MoO6-g-C3N4 on a PDA coated thin-film composite PVDF substrate by Schiff base reaction. The rejection rate of the simulated polysaccharide was more than 90%, and that of the simulated protein was more than 80%. The combination of the membrane and the photocatalyst promoted the degradation of tetracycline hydrochloride by the composite membrane to 67.85% when original membranes had minor effect. Under visible light, reversible radiation pollutants (Rr) gradually replaced irreversible pollutants (Rir) as the main pollutants. The flux recovery ratio (FRR) of 0D-2D Bi2MoO6-g-C3N4/PVDF membrane was 85% after being irradiated with visible light for 30 min. The flux recovery rate of contaminated photocatalytic membrane remained 75%, and the rejection was maintained in a stable range after four cycles of the cleaning operation under visible light. The results indicated that the excellent photocatalytic performance of 0D-2D Bi2MoO6-g-C3N4 photocatalysis material and the increase of multi-dimensional functional layer morphology on pollutant contact area improved the mechanical stability, interception performance and self-cleaning performance of the composite membrane. This work not only builds a new type of composite coating membranes, but also help us to further understand the relationship between the dimensions of photocatalytic materials and the improvement of photocatalytic membrane performance.

We evaluated the safety and immunogenicity of four doses of 20 or 60 ��g, and the immunogenicity and compliance of the short-term vaccination regimen (0, 1, and 2 months) among patients receiving MMT. We conducted a randomized controlled trial among 303 patients receiving MMT who were randomized to receive 3 or 4 doses of 20 or 60 ��g of recombinant hepatitis B vaccine. At month 7, the seroconversion rates in both IM20 �� 4 and IM60 �� 4 groups were numerically higher than the IM20 �� 3 group (P > 0.05). The high-level responses and geometric mean concentration (GMC) of anti-HBs in both IM20 �� 4 and IM60 �� 4 groups were significantly higher than the IM20 �� 3 group (P 0.05). The completion rate of the short-term high-strength vaccination group was significantly higher than the standard vaccination group (P 0.05), with similar immunogenicity (P > 0.05). Both the high-strength and standard-strength four-dose hepatitis B vaccine regimens could improve the immune response for patients receiving MMT. The high-strength short-term vaccination regimen could improve compliance and attain comparable immunogenicity with the standard vaccination regimen. The high-strength short-term vaccination regimen is recommended and the fourth dose is encouraged for this population considering the compliance and immunogenicity. ClinicalTrials.gov (NCT03962816)

This article presents a new direct load voltage control method for electrolytic capacitorless wireless power transfer (WPT) system without dc/dc converter. In specific, the three-phase low-frequency ac to the high-frequency ac (HFac) converter is employed into the electrolytic capacitorless WPT system by using the bidirectional power switches. The HFac voltage is directly generated on the transmitting tank without using the electrolytic capacitor. Furthermore, in order to realize the discretionary and accurate load voltage control without dc/dc converter, the nine voltage vectors, including six effective voltage vectors and three zero voltage vectors, are selectively exported for the transmitting tank with different duty cycles. In addition, the unity power factor correction and direct load voltage control are both achieved only by transmitting side control. Meanwhile, theoretical analysis of double series-compensated transmitting network and duty cycles under resonant frequency calculation in microchip are demonstrated in detail. Finally, both simulation and experimental results are provided to verify the feasibility and correctness of the proposed system, which operates at 85 kHz with 90% efficiency and about 9% total harmonic distortion.

This article is to present the design, analysis, and verification of a new hybrid wireless power transfer (HWPT) system, which has a space-saving coupler structure. The key of the design is to simplify the two coupling capacitor plates into one single frame-shaped plate at each side. Then, the coupling coil for inductive power transfer (IPT) is embedded into the metal frame to form a compact hybrid coupler. Meanwhile, the coupling polarity between the coils is specified to realize the superposition of the inductive and capacitive coupling. As a result, the proposed HWPT system can offer a good comprise of efficiency promotion and a space-saving coupler structure simultaneously. To illustrate the system working principles, the equivalent circuit model is first derived. Then, a detailed analysis is conducted in terms of the reflected impedance. Consequently, the mechanism of the efficiency promotion can be clearly explained. Finally, a prototype is constructed with several experiments, which validate the effectiveness of the proposed HWPT system. Results show that an efficiency increase of 14% over the pure IPT is obtained at 35-cm distance. Moreover, the effects of varying the resonant frequency are also carried out to instruct the practical system design.

In this work, an amino-terminated polyether (ATP) was synthesized and used for the functionalization of GO to obtain an amino-terminal polyether-functionalized graphene oxide (FGO). The structure o...

In this article, a new double-rotor multiwinding machine (DRMWM) that utilizes the flux modulation principle is proposed for propulsion system of hybrid electric aircrafts (HEAs). First, the operation principle of DRMWMs and the corresponding HEA propulsion configuration are introduced, where different operation modes of two rotors and three sets of windings of DRMWMs to cope with various flight tasks of HEAs are elucidated. Then, an improved subdomain method is utilized to solve the magnetic field distribution of DRMWMs with the consideration of saturation effect of soft-magnetic material (SMM). Finally, a prototype is manufactured to verify the effectiveness of the proposed improved subdomain method in predicting the electromagnetic performances of DRMWMs. The experiment shows that the DRMWM is a good candidate to be applied in HEA with different operation modes.

This article studies the rotational movement and charging torque in a new reconfigured on-board charger during the charging process. Recently, the reconfigured on-board charger becomes attractive because the propulsive units are engaged in the charging system to reduce the cost and volume. Since the unbalanced currents flow through the three-phase permanent-magnet synchronous machine, the rotational movement and charging torque are generated. The charging torque may be equal to the rated propulsive torque at some special rotor positions, which is unsafe and may lead to the rotational movement, extra noise, and motor wear. In order to reduce the influence of charging torque and rotational movement during the charging process, the charging torque is analyzed based on the magnetic coenergy. It is found that the charging torque is related to the unbalanced current, differential-mode current, and current ripple in motor windings. Thus, the mutual inductances of motor windings during the charging process are decoupled into the differential-mode and common-mode inductances. Furthermore, a solution is provided to significantly minimize the charging torque based on the control methods of the ac/dc side and dc/dc side. Finally, the experimental results are provided to verify the correctness of the suppression of rotational movement and the charging performance.

Most of the existing one-to-multiple wireless power transfer systems are single-channel one-to-multiple wireless power transfer (SOWPT) systems. They only utilize one power channel to charge multiple receivers. In this article, a novel multichannel one-to-multiple wireless power transfer (MOWPT) system is proposed, which can deliver power to different receivers simultaneously with separate power channels. In the proposed MOWPT system, the composited compensation topology is utilized to build multiple power channels, which possess totally different resonant frequencies and nearly do not affect each other. Compared with those existing SOWPT systems, the power of receivers of the proposed MOWPT system can be simply and separately controlled by changing the duty cycles of the inverters without a complex control method and extra dc–dc converters. In order to analyze the performances of the proposed MOWPT system, a 0- LC MOWPT system, which utilizes the air transformers to provide multiple power supplies of different frequencies, is modeled and analyzed in detail. Moreover, based on the analysis results, a corresponding parameter design method is proposed to simplify the design procedure of this MOWPT system. Finally, an experimental prototype is built up to verify the performances of the proposed MOWPT system and the parameter design method.

This article proposes the permeance and inductance modeling of a new double-stator hybrid-excited flux-switching permanent-magnet (DSHE-FSPM) machine. First, based on the machine design, the DS coupling analysis is presented, which refers to the mutual influence between double stators. In fact, different coupling degree leads to different modeling methods of DS machines, which reduces the workload and increases the modeling efficiency. For DS-FSPM machines, the main affecting factors of the coupling degree are the rotor configuration, PM mutual suppression, and load condition. The specific influences of all the factors are summarized. Second, based on coupling analysis, analytical permeance–magnetomotive-force (MMF) model fit for typical DS-FSPM machines is built up. The effects of hybrid excitation and flux barriers are also taken into consideration. The analytical results accommodate great agreement with simulated counterparts. Third, based on the magnetic field deduction, the inductance model is built, considering leakage inductances. As a result, the analytical inductance well agrees with the simulated and measured counterparts within the calculation error of 5%. Also, the inductance mismatch experiments are carried out with the prototype, which can further verify the modeling of the proposed DSHE-FSPM machine.

This paper proposes the multi-objective optimization of a double-stator hybrid-excited flux-switching permanent-magnet (DSHE-FSPM) machine, which aims at the contradictory objective achievement. Firstly, the proposed machine topology is presented. Also, the general analytical geometric model is built up, which matches the typical DS-FSPM machines. Secondly, the archive-based multi-objective genetic algorithm (AMOGA) optimization is carried out. The contradictory multi-objectives contain the maximum efficiency, minimum PM cost, and minimum torque ripple. Also, the minimum inner and outer radial force difference is included, which can effectively reduce the vibration and manufacturing difficulty. Additionally, before the optimization process, the sensitivity analysis is employed to alleviate the calculation burden. Thirdly, the hybrid flux-modulating machine performances and the prototype experimental results are presented, which can verify the feasibility of the proposed optimization strategy and the optimal machine design.

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.

This paper presents a model predictive control for a six-phase permanent magnet synchronous machine (PMSM) with a reduced-dimension cost function. Only the variables in the harmonic subspace are included into the cost function, while the energy conversion related variables are excluded. This is achieved by using the deadbeat direct torque and flux control method to obtain a reference voltage vector and then to track the torque and stator flux properly in the energy conversion related subspace. Then, according to the position of the reference vector, the appropriate prediction vectors can be determined. Subsequently, a reduced-dimension cost function including only the harmonic constraints is defined to evaluate the feasible prediction vectors. In this way, the predictive model and the cost function are simplified without redundant constraints. Meanwhile, the torque and flux can be regulated satisfactorily, and the harmonic currents are suppressed effectively. Finally, experimental results of the proposed method and the conventional model predictive torque control are presented in this paper to verify the validity of the proposed method.

International audience; This paper presents an analytical subdomain model for the prediction of various electromagnetic parameters of magnetic-geared double-rotor machine (MGDRM). By dividing the MGDRM into six subdomains and solving the Maxwell equations in polar coordinates for each region, the vector magnetic potential distribution can be derived. Subsequently, the flux density distribution, back electromotive force (EMF), and output torque, can be calculated. Furthermore, based on the proposed model, the equivalent d-q axis is elaborated. Also, the corresponding d and q inductance can be obtained. It proves that the MGDRM can be regarded as a non-salient-pole synchronous machine. Besides, the power factor of the MGDRM under i d =0 control is deduced and optimized for the different thicknesses of modulators. In addition, the demagnetization capability is analysed by adopting the subdomain model. Finally, the accuracy of proposed subdomain model for MGDRMs is validated via the finite-element method (FEM).

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.

Flux-modulated double-rotor (FMDR) machine topology has recently attracted much attention, particularly for the hybrid electric vehicle (HEV) propulsion. To maintain the driving stability and safety of the vehicle, the analysis of the magnetic force and the evaluation of the vibration performance for such kind of machine are indispensable. However, for the FMDR machine with the magnetic-gearing (MG) effect, there are at least two rotating magnetic fields with different speeds and frequencies. This leads to the complicated time harmonics of the radial force density. Actually, the publications on the FMDR machine hardly take into account the magnetic force or vibration characteristics. In this article, the sources, variations, and different kinds of magnetic forces are thoroughly investigated for a proposed FMDR machine. First, the machine topology and operation principle are introduced. Second, the theoretical analysis of the flux density and radial force density is implemented from the harmonic point of view, which is followed by the finite-element simulation, comparison, and validation. Also, an effective solution is proposed and discussed for the problem of different mixed electrical frequencies in the machine. Finally, the distributions of different kinds of magnetic forces appearing in the FMDR machine are concluded.

In this paper, a novel kind of wireless motors, namely, the LCC -compensated wireless switched reluctance motor, is proposed and implemented. The definite advantages are that there is no power converter at the motor side and particularly no switched-capacitor array at the transmitter side to realize the multiple-frequency operation. The key is to develop an LCC compensation involving an inductor and two capacitors (the so-called LCC ) for a multiple-frequency wireless power transfer system. As a result, only one transmitter is needed to targetedly feed three receivers, which directly energize the three phase windings of the motor. Particularly, there is no need to control switched capacitors to change the resonant frequency of the transmitter. Meanwhile, the burst firing control method is employed to realize the speed control. Both calculation and experimental results are presented to validate the feasibility of the proposed system. In the system prototype, the transmission distance can reach up to 150 mm and the transmission efficiency can be achieved up to 80%.

Purpose To systematically evaluate the effects of Electronic health (eHealth) interventions on fatigue, pain, and sleep disorders in cancer survivors. Design A systematic review and meta-analysis was conducted. Methods Relevant studies were searched from five databases (MEDLINE, Embase, the Cochrane Central Register of Controlled trials, CINAHL, and PsycINFO). The comprehensive literature search was done in December 2020. Only randomized controlled trials (RCTs) that examined the effects of eHealth interventions among cancer survivors were included. Findings Twenty-five RCTs were included. The meta-analysis showed that eHealth interventions had a positive impact on pain interference (SMD = -0.37, 95% CI: -0.54 to -0.20, p = 0.0001) and sleep disorders (SMD = -0.43, 95% CI: -0.77 to -0.08, p = 0.02) but not on pain severity or fatigue in cancer survivors. The sensitivity and subgroup analyses indicated that the pooled results were robust and reliable. Conclusion eHealth interventions are effective in improving pain interference and sleep disorders in cancer survivors. Additional high-quality RCTs are needed to test the effectiveness of eHealth interventions on fatigue, pain, and sleep disorders in cancer survivors. Clinical relevance This systematic review and meta-analysis provides evidence to offer effective and sustainable eHealth care for symptom management among cancer survivors.

Electric machines with high torque density are needed in many applications, such as electric vehicles, electric robotics, electric ships, electric aircraft, etc. and they can avoid planetary gears thus reducing manufacturing costs. This paper presents a novel axial-radial flux permanent magnet (ARFPM) machine with high torque density. The proposed ARFPM machine integrates both axial-flux and radial-flux machine topologies in a compact space, which effectively improves the copper utilization of the machine. First, the radial rotor can balance the large axial forces on axial rotors and prevent them from deforming due to the forces. On the other hand, the machine adopts Halbach-array permanent magnets (PMs) on the rotors to suppress air-gap flux density harmonics. Also, the Halbach-array PMs can reduce the total attracted force on axial rotors. The operational principle of the ARFPM machine was investigated and analyzed. Then, 3D finite-element analysis (FEA) was conducted to show the merits of the ARFPM machine. Demonstration results with different parameters are compared to obtain an optimal structure. These indicated that the proposed ARFPM machine with Halbach-array PMs can achieve a more sinusoidal back electromotive force (EMF). In addition, a comparative analysis was conducted for the proposed ARFPM machine. The machine was compared with a conventional axial-flux permanent magnet (AFPM) machine and a radial-flux permanent magnet (RFPM) machine based on the same dimensions. This showed that the proposed ARFPM machine had the highest torque density and relatively small torque ripple.

Fast online detection of inter-turn short-circuit faults for permanent magnet synchronous machines (PMSMs) is a challenging task. Previous attempts based on phase currents or back EMF monitoring lack the capability to accurately locate the inter-turn short-circuit faults in stator windings. This paper proposed a new approach to online inter-turn short-circuit fault detection for PMSMs by means of sensing the external stray magnetic field outside the motor stator yoke. The stray magnetic field provides the information about the phase currents as well as the status of stator windings and thus, the location of inter-turn short-circuit fault can be detected accordingly. In this paper, the inter-turn short-circuit model and the stray magnetic flux model for PMSMs were theoretically analyzed. Both FEM simulations and experiments have been presented to validate the effectiveness of the proposed approach. A sensor array composed of 24 sensitive tunneling magnetoresistive (TMR) sensor units was employed to measure the stray magnetic field distribution outside the PMSM stator yoke. The experimental results show that both the location and severity of the inter-turn short-circuit fault in PMSMs were effectively detected using the proposed approach.

This paper proposes a multi-vector-based model predictive torque control with fixed switching frequency for a six-phase permanent-magnet synchronous machine to improve its steady-state performance. First, two active vectors are synthesized in each control period to suppress the stator current harmonics in x–y subspace. For the sake of easy implementation in the real-time system, the vectors are artfully synthesized in two different manners. Second, to achieve the fixed switching frequency, two null vectors are inserted along with the synthesized vector. The duty ratio of the null vectors is determined based on the principle of deadbeat torque control. In the meantime, the synthesized vector and its duty ratio are evaluated simultaneously by the cost function. In this way, the torque ripple can be reduced considerably. Thus, with the proposed method, both the current harmonics and the torque ripple are reduced effectively. Also, the proposed methodology can be readily implemented practically under the constant switching frequency. Finally, the experimentation is carried out to verify the validity of the proposed method.

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.

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.

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.

This paper presents a new effective sandwiched wireless power transfer (WPT) system, which is adopted to recharge the battery of a micro medical robotics for a cardiac pacemaker. The key of the design is to use the distinct sandwiched topology in both the transmitter and receiver coils, whose operating frequency of 160 kHz is significantly lower than the reported WPT system up to megahertz. Furthermore, the implantable receiver adopts the bilateral coil design, which can harness more power within a limited size. Meanwhile, with the sandwiched transmitting coils, the proposed design achieves the high feasibility and flexibility of the controllable distance for different kinds of micro medical robotics in patients. As a result, the proposed system can provide the power as high as 5 W and the transmission efficiency up to 88%. Finally, the corresponding theoretical analysis, simulation, and experimentation are carried out to prove the validity of the proposed sandwiched medical WPT system for the implantable device in the patient body.

In this paper, a wireless ballastless lighting system for fluorescent lamps is proposed and implement-ted. The key is to utilize magnetic resonant coupling to achieve wireless power transfer (WPT) while igniting the fluorescent lamp without using any magnetic or electronic ballast. Meanwhile, series-parallel compensation is identified to be more suitable for this WPT system. Also, burst firing control is utilized to achieve efficient light dimming. In order to achieve the fully wireless feature, remote lighting control via Bluetooth is realized by a smart phone. As an example, an experimental setup, which can light up an 8 W fluorescent lamp with illuminance of 2330 lx, has been designed and developed. In particular, it can achieve the transmission efficiency of 57% and the operating frequency of 51 kHz, with distance up to 56 cm. Both theoretical analyses and experimental results are given to validate the feasibility and flexibility of the proposed system.

The stochastic variation of photovoltaic (PV) generation units in the distribution grid has increased complexity of the optimal dispatch. Updated power electronics devices such as power electronics transformer (PET) are installed to improve the energy efficiency of DC power appliances and the control flexibility. The synergy effects of optimal dispatch of photovoltaic units and updated PET operation are analyzed in this paper. A two-stage optimization model is established to search for the best configuration and operation of distribution grid with updated PET feeders and photovoltaic inverters. The optimal configuration of PETs is given in the upper stage and given to the lower stage as input parameters to regulate the active and reactive power of photovoltaic inverters associated with operation of feeders updated with PETs. The coordinated optimization between updated PETs and photovoltaic generation units is developed to minimize the operation cost and total power losses in the distribution grid. NSGA-II algorithm is adopted to solve the proposed multi-objective optimization with constraints from both reliable operation of power system and power electronics devices. Comparisons between the simulation results with and without the proposed coordinated optimization for PETs and PVs valid the effectiveness of two-stage optimization model. The operation cost and power losses are reduced while avoiding the power curtailment of PV units by optimally configuring and regulating the power electronic devices including the PETs and inverters of PVs in the test distribution network.

In this paper, a new class of wireless secondary converterless switched reluctance motor (WSC-SRM) drives is proposed and implemented. The key is to develop a unique wireless power transfer (WPT) system to directly drive the SRM without involving any power converter at the motor side. This is particularly essential to enable the WSC-SRM to work in an isolated environment without maintenance. Based on the selective WPT, the phase windings of the SRM can be properly energized by the same transmitter that adopts a newly developed compound structure. Meanwhile, signal duty ratio control of the transmitter is employed to achieve the speed control of the WSC-SRM. Both simulation and experimental results are given to validate the feasibility of the proposed system. For exemplification, a prototype is designed and constructed, which can provide WPT up to 150-mm transmission distance and achieve up to 72.8% transmission efficiency.

This paper explored that the novel waterborne polyurethane (WPU) composite coatings with superior corrosion protection performance was fabricated via intercalating functionalized graphene oxide (GO). The eco-friendly and superhydrophobic aminoethyl aminopropyl isobutyl polyhedral oligomeric silsesquioxane (POSS-NH-NH2) was applied to modify GO via facile one-step chemical grafting. Several analyses such as FT-IR, XRD, Raman, and SEM were performed to verify the successful graft of POSS-NH-NH2 into the GO. Sequentially, the WPU and WPU composite coatings containing GO and functional graphene oxide (PNNG) nanoparticles were prepared and applied on Q235 steel with a thickness of 55 ± 5 μm. The corrosion protection performance of coatings was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization. The results highlighted that well-dispersed and hydrophobic PNNG nanoparticle remarkably enhanced the corrosion protection performance of WPU. In detail, the protection efficiency of WPU composite coatings with 0.1 wt.% PNNG reached 99.79% relative to pure WPU. After 21 days’ immersions in 3.5 wt.% NaCl aqueous solution, the ǀZ|f=0.01Hz of WPU decreased to 1.96×105 Ω·cm2 from 1.52 ×107 Ω·cm2. However, the ǀZ|f=0.01Hz of WPU with 0.1 wt.% PNNG was 1.48×108 Ω·cm2 after 180 days’ immersions, which was still about 3 orders of magnitude higher than that of WPU.

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.

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.

With ever-increasing concerns on health and environmental safety, there is a fast-growing interest in new technologies for medical devices and applications. Particularly, wireless power transfer (WPT) technology provides reliable and convenient power charging for implant medical devices without additional surgery. For those WPT medical systems, the width of the human body restricts the charging distance, while the specific absorption rate (SAR) standard limits the intensity of the electromagnetic field. In order to develop a high-efficient charging strategy for medical implants, the key factors of transmission distance, coil structure, resonant frequency, etc. are paid special attention. In this paper, a comprehensive overview of near-field WPT technologies in medical devices is presented and discussed. Also, future development is discussed for the prediction of different devices when embedded in various locations of the human body. Moreover, the key issues including power transfer efficiency and output power are addressed and analyzed. All concerning characteristics of WPT links for medical usage are elaborated and discussed. Thus, this review provides an in-depth investigation and the whole map for WPT technologies applied in medical applications.

The use of dual recognition and multiple detection modes is an attractive strategy for realising sensors with improved selectivity and accuracy. Herein, a molecularly imprinted polymer (MIP)-based sensor is developed for amoxicillin detection based on two detection modes (fluorescence and electrochemiluminescence) and dual recognition. First, graphene oxide loaded with CdTe quantum dots/gold nanoparticles (GO/CdTe/Au NPs) is coated onto an indium tin oxide (ITO) electrode. Then, 4-mercapto-calix[6]arene is bonded to GO/CdTe/Au NPs as the first recognition element, which then form a host–guest complex with the target molecule amoxicillin. Subsequently, as the second recognition element, an MIP is prepared on the ITO electrode. After amoxicillin is removed from the MIP, specific identification sites for amoxicillin are obtained. Furthermore, the GO/CdTe/Au NPs can generate fluorescence and electrochemiluminescence signals that are effectively quenched by amoxicillin. Therefore, on/off switching of these signals can be achieved through the elution or adsorption of amoxicillin. The dual detection modes are complementary and provide mutual authentication, which can improve the detection accuracy and application scope. Moreover, the dual recognition sites for amoxicillin, improve detection selectivity. The fluorescence and electrochemiluminescence modes have detection ranges of 5–1000 × 10−11 mol L−1 and 5–1500 × 10−11 mol L−1, respectively, with detection limits of 9.2 × 10−12 mol L−1 and 8.3 × 10−12 mol L−1, respectively.

Cognitive and mental impairments are common health problems in acute ischemic stroke (AIS) patients. In this study, we aimed to assess the benefit of a reminiscence therapy–based care (RTBC) program on cognitive impairment restoration, anxiety, and depression reduction in AIS patients. Totally 130 AIS patients were recruited in this randomized, controlled study and randomly assigned to the RTBC group or control group in 1:1 ratio for 12-month intervention. Mini-Mental State Examination (MMSE), Montreal cognitive assessment (MoCA), Hospital Anxiety and Depression Scale for anxiety/depression (HADS-A/HADS-D), and Zung self-rating anxiety/depression scale (SAS/SDS) were assessed at month 0 (M0), M3, M6, M9, and M12. Meanwhile, patients’ satisfaction was also evaluated at M3, M6, M9, and M12. RTBC increased MMSE score and MoCA score and reduced cognitive impairment patients’ percentage assessed by MoCA score at M12 compared with control. RTBC reduced HADS-A score at M12, but not anxiety patients’ percentage or severity by HADS-A at M12; besides, RTBC significantly lowered the SAS score at M9 and M12, and anxiety patients’ percentage and severity by SAS at M12 compared with control. RTBC reduced HADS-D score at M9 and M12 (while statistically non-significant), but not depression patients’ percentage or severity by HADS-D at M12; it decreased SDS score at M9 and M12, but not depression patients’ percentage or severity by SDS at M12 compared with control. Additionally, RTBC obsessed higher patients’ satisfaction at M3, M6, and M12 compared with control. RTBC could help reduce cognitive impairment, anxiety, and depression in post-stroke management for AIS patients.

In this paper, a phase-decoupled flux-reversal linear generator for low-speed reciprocating power generation is presented. The proposed linear generator adopts a short-primary and long-secondary structure. The primary consists of six identical C-cored modules housing both permanent magnets (PMs) and the armature winding. The secondary is passive and stationary. By using the independent C-cored modules and flux-reversal configuration, six phases are magnetically decoupled from each other. In order to maximize the delivered power from the linear generator to the load, an impedance matching strategy is applied to suppress the circuit reactance. Both simulation and experimentation are carried out to verify the effectiveness of the proposed linear generator and the impedance matching strategy.

To improve the efficiency of the tidal energy conversion system, high power density and high efficiency direct-drive permanent magnet synchronous generators are required. Therefore, this paper combines the magnetic-gearing effect with the generator and proposes a novel six-phase vernier generator topology. First, the topology is introduced and the operation principle is described. Second, the paper focuses on the induced voltage optimization by different methods, including parametric optimization, response surface method, and harmonic winding suppression. Also, the induced voltage performance is validated by FEM. Finally, the optimal design is proposed and the conclusions are drawn upon.

A two-dimensional surface covalent organic framework, prepared by a surface-confined synthesis using 4,4'-azodianiline and benzene-1,3,5-tricarbaldehyde as the precursors, was used as a host network to effectively immobilize arylenevinylene macrocycles (AVMs). Thus AVMs could be separated from their linear polymer analogues, which are the common side-products in the cyclooligomerization process. Scanning tunneling microscopy investigations revealed efficient removal of linear polymers by a simple surface binding and solvent washing process.

Two-dimensional self-assembly of star-shaped 2,4,6-tris(4-bromophenyl)-1,3,5-triazine (BPT) molecule is investigated both on highly oriented pyrolytic graphite (HOPG) and single-layer graphene (SLG) grown on a polycrystalline Cu foil. Scanning tunneling microscopy (STM) reveals that this molecule can form different self-assembling structures on these two different surfaces. On the basis of high-resolution STM images, we find that BPT molecules can form compact and loose assembly patterns with different packing densities on HOPG surface and a porous structure with hexagonal-like cavities on SLG surface. A combination of STM and density functional theory calculations elucidates the interplay of molecule–molecule and molecule–substrate interactions on the assembling behavior on both substrates.

This paper presents a technique to measure the velocity of permanent magnet synchronous motors (PMSMs) by sensing the external stray magnetic field outside the stator yoke. A magnetic- equivalent circuit model for the surface-mounted PMSM was developed to analyze the behavior of the stray magnetic field. The external stray magnetic field can provide the position and the speed information of motor rotor. Simulation by means of a 3-D finite-element-method modeling and experimental results over a wide speed range are presented to substantiate the successful application of the proposed technique. A sensitive triaxial tunneling magnetoresistive sensor was employed to measure the stray magnetic field outside the motor stator yoke. The proposed method was validated in both steady and transient operating conditions, and it demonstrated small measurement errors in the range between −0.17% and 0.55% over the speed range from 50 to 1000 rpm. Therefore, it verifies that the proposed technique can provide an easy-to-operate, low-cost, and high-accuracy alternative to the velocity measurement for PMSMs.

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.

Corrosion protection of water-borne polyurethane (WPU) containing phytic acid-decorated graphene oxide (PG) for Q235 steel was investigated in this work. Natural and non-hazardous phytic acid (PA) was applied to modify graphene oxide (GO) for enhancing its dispersion and compatibility with WPU. The results of Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Thermalgravimetric analysis, and Atomic force microscopy demonstrated successful decoration of GO by PA. Scanning electron microscopy and Field-emission high-resolution transmission electron microscopy were used to reveal the morphology structures of GO and PG. The electrochemical impedance spectroscopy and polarization curves were applied to investigate the anti-corrosion performance of WPU loaded with PG nanoparticles. Results revealed that the WPU/PG composite coatings presented an excellent enhancement in long-term anti-corrosion performance. The reason was that the modification of GO by PA not only improved compatibility with WPU, enabling the formation of an efficient barrier to play a physical anti-corrosion effect, but also formed stable metal chelate complexes with iron ions. Moreover, WPU/PG0.05 has the best anti-corrosion ability and “self-healing” function to some degree. Therefore, the advantages of PG can be used as an effective anti-corrosion nanofiller in practical application.

Reduced graphene oxide (rGO)-titanium dioxide (TiO2) hybrid material has been prepared through a facile hydrothermal method for ammonia detection at room temperature. The combined characterizations including X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV–vis) and scanning electron microscopy (SEM) indicated the successful formation of rGO-TiO2 hybrid. It also showed that the morphology of graphene sheets was greatly improved to become porous and undulating due to introduction of synthetic titanium dioxide. Accordingly, the hybrid-based sensor showed much more excellent sensing properties in comparison to that of bare graphene film sensor. The mechanism for the improvement could be ascribed to the synergetic effect between rGO sheets and TiO2 nanospheres, specifically, the enrichment of active adsorption sites on account of the supporting function of TiO2 nanospheres.