This paper presents a new permanent magnet vernier machine with radial hybrid consequent-pole (HCPMVM), which has the merits of high torque and low torque ripple. The PMVM is based on the theory of flux modulation effect, and the CP can effectively enhance the amplitudes of the modulation harmonics. Therefore, the utilization of the modulation harmonics can be maximized by selecting the appropriate the pole ratio and the torque can be effectively improved. However, CP tends to bring high torque ripple, which is caused by the different permeability characteristics of the PM pole and the iron pole. The HCP structure reduces the permeability difference by reducing the radial top height of the iron pole, and fills the PM to improve the air-gap flux density. Then, the geometrical configuration of HCPMVM is presented, together with electromagnetic performances are analyzed by finite element analysis. The analyzed results validate the employment of HCP can effectively improve steady torque and decrease torque ripple.

This article presents a new permanent magnet (PM) rotor with radial hybrid-layer consequent pole (RHCP) for flux modulation machines, the merits of high steady torque and low torque ripple, which can be used in industrial robots. The proposed RHCP structure is composed by subtracting the iron pole thickness in the consequent pole (CP) and laminating the upper-layer PM, which can reduce the magnetic permeability imbalance between the poles and improve the air-gap flux density. By adjusting the thickness of the iron and PM of the hybrid poles in the RHCP, the amplitude of the fundamental harmonic and modulation harmonics in the air-gap flux density can be optimized. This allows for the maximization of the utilization of the working harmonics by selecting the appropriate thickness proportion, leading to an effective improvement in torque production. In addition, the upper-layer PMs in hybrid poles can effectively reduce the torque ripple caused by the unipolar magnetic flux leakage in CP arrangement. The geometrical configuration of field modulation machines (FMMs) with RHCP is presented, together with electromagnetic performances are analyzed by finite element analysis (FEA). The calculated results validate that the employment of RHCP can effectively improve steady torque and decrease torque ripple.

This paper presents two new dual-stator machines using squirrel teeth in uneven distribution (STUDDSMs), which have the merits of low cogging torque and low torque ripple. The proposed STUD can be designed by changed width (CW) and shifted position (SP) of squirrel stator teeth, which keeps the volume of squirrel stator equal. The airgap flux density can be modulated based on flux modulation effect and regulated according to the proposed STUD for high torque density and low total harmonic distortion, respectively. Then, the geometrical configurations of CW-STUDDSM and SP-STUDDSM are presented, in which they share the same key parameters for a fair comparison. The design consideration of these two STUDDSMs are provided, together with the cogging torque and steady torque are analyzed by finite element analysis. The analyzed results validate the employment of STUD can effectively decrease cogging torque and torque ripple.

Increasing industrial development puts forward high requirements for the performances of stator permanent magnet (PM) machines, such as torque density and efficiency. The paper proposes a new dual stator PM machine based on field modulation theory (DSPMM), which employs the intermediate rotor participating in the electromechanical energy conversion of the internal and external machine. The proposed machine has the advantages of high torque density and high efficiency and solves the problem of insufficient space utilization of a single stator machine. The evolution process and working principle of the proposed DSPMM are studied. The flux-switching-type PM (FSPM) and the flux-reversal-type PM (FRPM) are employed in the proposed DSPMM, which forms four representative machines. For a fair comparison, the proposed machines employ identical key parameters, i.e., PM volume, the outer radius of the outer stator, and active airgap length. Based on finite element analysis (FEA), the electromagnetic performances of the four representative DSPMM under no-load and rated load, and different copper consumption conditions are analyzed and compared. The calculated results show that the proposed DSPMM with inner FSPM stator and outer FRPM stator can provide high output torque, low torque ripple, high power factor, and high efficiency.

A large-scale photovoltaic (PV) power plant is composed of hundreds and thousands of PV modules, which makes the fault diagnosis a challenging problem due to its complexity. It is well known that the characteristics of a PV array highly depends on the environmental conditions. At the meanwhile, the line faults inside the PV array may also lead to the changes in its characteristics. Thus, how to distinguish the real faults from the environmental issues is an important problem. The paper proposes an improved fault diagnosis method that is based on maximum power point estimation (MPPE) to diagnose the abnormal faults. It is based on curve-fitting techniques, which does not require any additional hardware or measurement support. The effectiveness of the proposed scheme is validated by simulations and experiments.

A simple and improved analytical model (AM) for linear permanent magnet synchronous machine (LPMSM) based on the correction factor is presented in this paper. A slotless linear permanent magnet machine (PLPM) with AM developed in Cartesian coordinate is selected to investigate. Consequently, the fitting equations of curvature factors for the permanent magnet and armature are obtained. The subdomains for LPMSM are simplified from 6 down to 3 domains based on curvature equations. The magnetic flux density and force show that the proposed approach agrees with the finite element (FE) model. Moreover, the reduced calculation domains and harmonic orders make AM proposed in the paper much faster. The main contribution of the work is to present a simple strategy for coordinate transformation and calculation strategy for LPMSM, which provides guideline for designers to investigate the machines developed in Cartesian coordinate.

Photovoltaic (PV) industry has been rapidly grown over the past decades. PV modules are the component of the PV systems that is easily susceptible to rigorous working conditions, which can result in a variety of defects affecting the system’s performance and lifespan if not diagnosed in time. Thus, it is necessary to understand the characterization of each fault and principles of every diagnosis method. This paper provides a comprehensive review of common faults within the context of the PV arrays, addressing the faults type, causes, and their effects on the I-V curve performance. In the previous studies, the main focus of overview is the efficiency and reliability of the direct diagnosis methods. As an important control method, the application of maximum power point tracking (MPPT) has become more and more extensive. This review also presents the latest MPPT-based techniques for diagnosing PV faults. Then techniques for PV diagnosing proposed in recent literature are analyzed and compared to point out their differences, the advantages and limitations and so on. This review will be of more interest to researchers and engineers working on PV power systems.

Partial shading condition (PSC) is an unavoidable complication in the field of photovoltaic (PV) systems. Bypass diodes and blocking diodes have become a standard feature to improve the performance of PV strings or arrays under PSC. However, the output current-voltage (I–V) characteristic varies with different shading patterns, which increases difficulties in theoretical analysis. In this paper, the output characteristics of series string, parallel string and series-parallel (SP) array under PSC are analyzed theoretically. The light levels are extended from simple three-level illumination to N-level illumination. This provides a theoretical basis for constructing the structure of PV arrays and researching the operational process of PV arrays under PSC analytically.

This study proposes a method to reduce the electromagnetic noise of a double-layer interior permanent magnet synchronous motor (DIPMSM) by optimising the flux barrier. First, a noise prediction model of the 36-slot/8-pole DIPMSM is established by finite element (FE). According to the simulation results, the noise of the motor is the loudest at 5000 rpm, especially with a noise component of 3333.3 Hz. From the results of modal analysis, it can be concluded that the four-order radial force with a frequency of 3333.3 Hz resonates with the stator, resulting in the loudest noise. Then, the source of the radial force that causes the loudest noise is analysed, and it can be found that the 9th and 11th harmonics of rotor magnetic motive force have the greatest contribution to the force. By optimising the rotor, the radial force contributed by the 9th and 11th harmonics is weakened, thereby reducing the noise caused by these harmonics. Finally, the electromagnetic performance and noise of the optimised motor are checked by FE. Compared with the initial rotor, the torque ripple is reduced by 26.79%, and noise is reduced by 5.542 dB. The noise test on the prototype verifies the accuracy of the noise prediction model.

A new hybrid magnetic source field modulation machine (HMS-FMM) is proposed in this paper, which can work in a wide speed range and guarantee high quality torque output. Due to the bidirectional flux modulation effect applied in HMS-FMM, a large number of working harmonics can be used to generate torque. Direct current excitation is employed to regulate airgap flux density at stator yoke for wide speed range and low harmonic distortion rate at flux weakening state. In order to improve the air gap flux density, the auxiliary tooth is introduced to connect ferrite and stator tooth for providing parallel magnetic circuit. The proposed topology, operating principle and key design parameters are described. Then, the electromagnetic performances are analyzed using finite element analysis (FEA) including magnetic field distribution, back electromotive force, torque characteristics and irreversible demagnetization assessment for magnets. The FEA-predicted results show that the proposed HMS-FMM is an appealing choice for electric vehicle application, which has the merit of high torque production with low torque ripple and safe operation without demagnetization risk in wide operation range.

A new dual-band bandpass filter (BPF) is designed and fabricated based on a pair of spherical dual-mode resonant cavities using 3-D printing technology. By elaborately introducing three-type metallic posts into each cavity to perturb the degenerated TM101 modes in a reasonable way, a dual-band coupling topology is developed in the design accordingly. Owing to the cross-coupling paths in the designed topology, two transmission zeros (TZs) are successfully introduced between the passbands, bringing out a high band-to-band isolation. Even more, TZs can also be generated by creating additional internal coupling paths to the presented dual-band coupling topology. Besides, the spherical cavity provides a higher quality factor and wider stopband, compared to that of a square or cylindrical cavity. To validate the design concept, a dual-band BPF prototype, operating at 12.0 and 12.5 GHz with respective bandwidths of 120 and 240 MHz, is implemented by 3-D printing process. The measured results exhibit good agreement with the simulated ones, showing more than 20-dB return losses and 20-dB dual-band isolation.

3 D打印技术出现在20世纪90年代中期,是制造业领域正在迅速发展的一项新兴技术.首先简单介绍了工业机器人领域的3D打印技术,并从打印精度、使用材料、打印层厚等方面对比分析了几种常见的3D打印技术中最适合与机器人结合应用的技术;然后重点介绍了机器人结合3D打印技术在建筑、金属、生物3个增材制造领域的应用进展.

The rise of three-dimensional bioprinting technology provides a new way to fabricate in tissue engineering in vitro, but how to provide sufficient nutrition for the internal region of the engineered printed tissue has become the main obstacle. In vitro perfusion culture can not only provide nutrients for the growth of internal cells but also take away the metabolic wastes in time, which is an effective method to solve the problem of tissue engineering culture in vitro. Aiming at user-defined tissue engineering with internal vascularized channels obtained by three-dimensional printing experiment in the early stage, a simulation model was established and the in vitro fluid–structure interaction finite element analysis of tissue engineering perfusion process was carried out. Through fluid–structure interaction simulation, the hydrodynamic behavior and mechanical properties of vascularized channels in the perfusion process was discussed when the perfusion pressure, hydrogel concentration, and crosslinking density changed. The effects of perfusion pressure, hydrogel concentration, and crosslinking density on the flow velocity, pressure on the vascularized channels, and deformation of vascularized channels were analyzed. The simulation results provide a method to optimize the perfusion parameters of tissue engineering, avoiding the perfusion failure caused by unreasonable perfusion pressure and hydrogel concentration and promoting the development of tissue engineering culture in vitro.

This letter presents a new compact multi-mode filtering power divider (FPD) design based on co-shared FPD topology with sharp frequency selectivity, improved out-of-band harmonic rejection and port-to-port isolation. Power splitting and quasi-elliptic filtering functions are achieved by masterly integrating only one triple-mode resonator. By loading different open-circuited stubs at the input/output ports, multiple additional transmission zeros (TZs) are generated at both lower and upper stopband, resulting in an improved stopband performance. Meanwhile, a better port-to-port isolation is obtained by adopting frequency-dependent resistor-capacitor parallel isolation network. The proposed multi-mode FPD design stands out from those in the literature by both nice operation performance and compact topology with only one resonator. For demonstration purposes, one triple-mode FPD prototype and its improved one are implemented, respectively. Measured results exhibit the superiority of the FPD design.

Three-dimensional bioprinting has emerged as one of the manufacturing approaches that could potentially fabricate vascularized channels, which is helpful to culture tissues in vitro. In this paper, we report a novel approach to fabricate 3D perfusable channels by using the combination of extrusion and inkjet techniques in an integrated manufacture process. To achieve this, firstly we investigate the theoretical model to analyze influencing factors of structural dimensions of the printed parts like the printing speed, pressure, dispensing time, and voltage. In the experiment, photocurable hydrogel was printed to form a self-supporting structure with internal channel grooves. When the desired height of hydrogel was reached, the dual print-head was switched to the piezoelectric nozzle immediately, and the sacrificial material was printed by the changed nozzle on the printed hydrogel layer. Then, the extrusion nozzle was switched to print the next hydrogel layer. Once the printing of the internal construct was finished, hydrogel was extruded to wrap the entire structure, and the construct was immersed in a CaCl2 solution to crosslink. After that, the channel was formed by removing the sacrificial material. This approach can potentially provide a strategy for fabricating 3D vascularized channels and advance the development of culturing thick tissues in vitro.

Vascular stent is an important kind of medical device for the treatment of the vessel occlusion.In this work, we designed and fabricated a kind of biodegradable vascular stent.The dynamics of expanding, compressing and bending process for the single "sine", "60 degrees sine" and "U" type stent unites were analyzed with Finite Element Method (FEA) respectively, and furthermore, the expanding characters of polylactic acid (PLA) stent models with length of 4mm, 6mm, and 8mm were simulated.The "sine" type bracket had a better dynamic property and thus was more suitable for medical stent implantation in terms of mechanical properties.Then, the stent errors including the movement, the nozzle deposition and the shrinkage of the material were analyzed which provided experimental basis for the designing of the stent.The brachial artery stent implantation on pig experimental animals was carried out using the 3D printed PLA vascular stents.Results showed that the 3D printed vascular could be transported into the stenosis place and expand the vessel after pulling out of the balloon.The blood supply function was normal and the biodegradation could be observed after 30 days.This paper provided a novel method for clinical transformation of biodegradable vascular stents.

At present,the mainstream control methods of permanent magnet synchronous motor are direct torque control and field-oriented control. The stability is the basis of these motor control algorithms and it is important to implementa-tion.In this paper,the stable operation range of permanent magnet synchronous motor direct torque control and permanent magnet synchronous motor field-oriented control is analyzed by combining the torque angle,flux linkage,power angle limiting and monotonicity of the system. A theoretical analysis is verified with the simulation,and the similarities and differences of stable operation of the two control algorithms are contrastively analyzed.

This paper introduces the automation level and update application of robot in construction,analyzes the typical technologies and sums up their characteristics.It also analyzes the basic reasons of the automation lags in construction behind the automation in industries,gives out the update technology of three dimensional print for the construction and makes a study of its key technology,including new construction material,software and control.Through experiments,the feasibility of the technology is approved.

[Objective]The application of electronic nose(EN) in identification for aging years of Liupao tea was re-searched to provide reference for establishing new quality evaluation technology system of Liupao tea. [Method]Response characteristic values of dry tea, tea infusion and wet tea leaf at different aging years from various producers were obtained by PEN3 portable EN smell analysis system. Principle component analysis(PCA) and linear discriminant analysis(LDA) were used to analyze their aging years and prediction model, and mahalanobis distance(MA),euclidean metric(EU) and discriminant function analysis(DFA) were applied in verification of accuracy of the prediction model. [Result]Liupao tea of different aging years had different response signals on EN. The EN response values of 171-175,166-170 and 155-160 s were selected as the characteristic values for dry tea,tea infusion and wet tea leaf to establish the identification model. LDA was better than PCA in distinguishing Liupao tea of different aging years. Samples of different aging years distributed in di-fferent regions. The cumulative contribution rates of discriminant LD1 and LD2 for dry tea,tea infusion and wet tea leaf were 93.00%,88.31% and 80.52% respectively. The verification accuracy of identification model for dry tea with EU,MA and DFA reached 88.23%,88.23% and 94.12%,identification model for tea infusion all reached 82.35% and for wet tea leaf reached 70.58%,82.35% and 94.12%. [Conclusion]EN can identify the smell characteristics such as aromatic substance in Liupao tea of different aging years, and realize distinguishing and classification. It can be used and promoted in the identification of tea aging years.

[Objective]The key technology for processing light-sugar dried jackfruit with natural flavor was explored in order to provide referential technologies for processing new type of non-sulfur dried fruits with low sugar and natural flavor.[Method]Yellow flesh jackfruit was taken as raw materials. Combining single factor test and orthogonal test , influences of different maturities of jackfruit on processing properties of natural flavor dried fruit , effects of different pulp pre-treatments on sugaring process and product quality, and effects of different ratio of sugar compound liquid on quality of dried fruit were studied, in a bid to determine the optimal solution for key processing technology of light-sugar dried jackfruit with natural flavor. [Result]The optimal processing for light-sugar dried jackfruit with natural flavor was as follows: ackfruits at 80%-90% maturity ripened by 1000 mg/L ethephon under 45 ℃ for 72 h were raw materials, heated in water adding 0.6%d-sodium erythorbate solution under 80 ℃for 3 min;then sugared the jackfruits with direct sugar replenishment and intermittent forced sugar solution(initial sugar solution degree 25 °Bx, adding 15% proportion of 75% maltose syrup and 0.3% glycerine) cycling technology; drained the fruits when the sugar solution remained stable at 35 °Bx. After stoving procedure, the dried jackfruits preserved the original smell and taste of fresh ones with soft texture, moderate sweetness and good taste, while moisture content≤18%, total sugar(calculated by reducing sugar)≤60%, residual sulfur dioxide≤0.02 g/kg. [Conclusion]Dried jackfruit produced with the combination of matured fruit processing technology , heat treatment for sterilizing, enzyme deactivation and color protection, and intermittent forced sugar solution cycling with low concentration sugar compound liquid can preserve the natural flavor of flesh jackfruit and contain low total sugar and sulfur dioxide residue. It fulfills the requirements of natural flavor preservation, light sugar and sulfur free. The technology can be applied to the actual production of new type light-sugar, sulfur-free dried fruits with natural flavor.