Current Issue : April-June Volume : 2023 Issue Number : 2 Articles : 5 Articles
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-switchingtype 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....
Due to the significant advantages of a high torque density, better fault tolerance and high efficiency, the combined star–pentagon winding has recently gained researchers’ interest. In this paper, a simple method to identify the sequence of phases of a five-phase machine with combined star–pentagon winding was proposed. This was accomplished using resistance measurements between adjacent and non-adjacent phases. The analysis was conducted to clarify the phase sequence identification method. A case study of a 5.5 kW five-phase synchronous reluctance motor with combined star–pentagon winding was considered to simply apply the proposed method using an LCR meter for resistance measurements. The parasitic and wire resistances are dominant in the studied case, and this did not influence the accuracy of this method....
The operating temperature and thermal stress play key roles in overall performance of a cylindrical roller bearing used in highspeed train traction motor. The cylindrical roller bearing studied in this paper is in the housing of the traction motor. Due to the heating of each component of the traction motor, a thermal environment is formed in the housing that changes the temperature and stress of the traction motor bearing. In this paper, a thermal-mechanical coupled model of bearing considering the stator, rotor, and shaft was established to study the temperature and thermal stress of traction motor bearing. Experiments were conducted on a service high-speed train to validate the proposed bearing thermal analysis model, meanwhile, the temperature of the measurement point was revised by the theory of heat transfer. The revised experiment results show that the established thermal-mechanical coupled model is reasonable and effective. The results show that the heating of the stator and rotor of the traction motor has a great influence on the temperature and stress of the cylindrical roller bearing of the traction motor. When the heating of the stator and rotor is considered, the temperature of inner ring near the traction motor is higher than that of far away from the traction motor, and the overall temperature of each component of the bearing also increases. As for the stress, when the traction motor stator and rotor is considered, the maximum stress increases by 66.9%. Therefore, the heating of the stator of the traction motor must be considered when the thermal characteristics analysis and reliability analysis are carried out on the cylindrical roller bearing....
As we move towards a decarbonized society, transparent solar cells have recently become an important means of increasing power generation in familiar locations. Copper oxide has been attracting attention as a candidate material for the production of transparent solar cells. In order to further expand the range of applications, it is believed that it will be necessary to develop flexible, transparent plastic substrates. For the purpose of optical applications, copper oxide thin films with CuO, Cu2O, or both phases were fabricated on highly transparent plastics such as poly-methyl methacrylate (PMMA) and polycarbonate (PC), as well as on a glass substrate as a comparable sample. The helicon plasma DC magnetron sputtering method was used to fabricate thin films at a low deposition temperature due to the low heat resistance of plastic substrates. In addition, the helicon plasma DC magnetron sputtering method is capable of depositing films at low vacuum pressure, which enables the preparation of thin films with high crystallinity. The structure, surface shape, and optical properties of fabricated films were investigated using X-ray diffraction (XRD), a laser microscope, and a UV-Vis spectrophotometer, respectively. In this study, the formation of copper oxide thin films on plastic substrates at low temperatures has been verified, as have the crystal structure and optical properties, which is considered a rare study in this field....
This paper investigates the joint states and parameters estimation problem for induction machine. In order to develop new states and parameters estimation methods that greatly improve the estimation bandwidth, this paper proposes an adaptive moving horizon estimation of the crucial states and parameters of the induction machine.The model of the machine under study is the one taking into consideration the magnetic saturation and the iron losses simultaneously. The estimator used is based on a least squares algorithm but includes a dead zone that ensures robustness and a variable forgetting factor that is based on the constant information principle. The simulation results show that the adaptive estimator can efficiently estimate the states and parameters of the induction machine with a fast convergence rate despite the initial parametric errors....
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