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Li X.,Harbin Electrical Machinery Company Ltd | Han X.,Harbin Institute of Technology | Wu Y.,Harbin Electrical Machinery Company Ltd
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2013

The Co-Ni-B composite particles with different mol ratio of Co to Ni were composited of spheres, spheres in-pair, hierarchical assemblies of dentrites, which were surfactant-free synthesized by chemical reduction method in aqueous solution. The complex permeability of the Co-Ni-B composite particles indicated reverse resonant peak at the frequency range of 8-16 GHz, where the complex permittivity showed the positive resonant peak and the μr″ of particles showed negative values, caused by the transformation between electric and magnetic energy. The imaginary parts of relative permeability (μr″) of Co-Ni-B composite particles indicated one broad resonant peak over the 2-8 GHz range for the high effective anisotropy. A slight decrease in complex permittivity resulted in an excellent impedance matching property. The Co-Ni-B composite alloy particles with mol ratio of 7:3 exhibited reflection loss less than -20 dB in frequency range of 4.0-14.5 GHz for the absorber thickness of 1.1-3.2 mm, and an optimal RL of -32.4 dB was obtained at 12.8 GHz with thickness of 1.2 mm. The broadest bandwidth of reflection loss less than -10 dB from 13.0 to 17.0 GHz, covering almost the whole Ku-band, was obtained for a thickness of 1.1 mm layer. © 2012 Elsevier B.V.

Wang Q.,Harbin Electrical Machinery Company Ltd
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2012

The characteristics of aluminum bronze material, using conditions and requirement for mechanical properties of porcelain sleeve flange were expounded. The porcelain sleeve flamge was produced by centrifugal casting. Through analyzing defects and implementing measures for eliminating defects, the proper centrifugal casting process was presented. By controlling strictly production process, the qualified porcelain sleeve flange was produced successfully.

Wang X.-Y.,Harbin Electrical Machinery Company Ltd | Qian X.-L.,Northeastern University China
2013 25th Chinese Control and Decision Conference, CCDC 2013 | Year: 2013

The selection of oriented vector control method for three-level PWM rectifier is an important factor for getting stable DC voltage. Because the observer has an uncertain initial value, and the rectifier has a large start-up current which may lead to the system failure, while using the virtual flux oriented vector control method for three-level PWM rectifier. For this reason, the grid voltage oriented vector control strategy was adopted to achieve a more effective control on the rectifier. However, the complex mathematical model of this method makes the controller designed difficultly. As the neutral point voltage balance of three-level rectifier can get a good control effect throughout the entire control process, the average current of the neutral point was regarded as zero. Besides, transforming symmetric three-phase parameter to constant DC parameter through appropriate coordinates transform can change the three-phase nonlinear system with time-variable issue into two-phase linear system, and the rational simplification of rectifier model was presented according to the project requirement, which has laid a foundation for the design of controller so as to make it easy for the selection of the PID controller parameters. At last, an effective control on the DC bus voltage and the grid power factor was achieved. © 2013 IEEE.

Wang H.,Tianjin Polytechnic University | Geng Q.,Tianjin Polytechnic University | Qiao Z.,Harbin Electrical Machinery Company Ltd
ICIST 2014 - Proceedings of 2014 4th IEEE International Conference on Information Science and Technology | Year: 2014

Particle swarm optimization (PSO) has made significant progress and has been widely applied to computer science and engineering. Since its introduction, the parameter tuning of PSO has always been a hot topic. As a robust design method, the Taguchi method is known as a good tool in designing parameters. Thus the Taguchi method is adopted to analyze the effect of inertia weight, acceleration coefficients, population size, fitness evaluations, and population topology on PSO, and to identify the best settings of them for different optimization problems. The results of benchmark functions show that the optimum parameter settings depend on the benchmarks, and all the functions obtain their optimum solutions after parameter tuning. Good result are also achieved when dealing with the optimization design of a Halbach permanent magnet motor, which indicates that the PSO with best parameter settings identified by the Taguchi method is more suitable to such actual engineering problem. © 2014 IEEE.

Pang L.-J.,State Key Laboratory of Hydropower Equipment | Zhong S.,State Key Laboratory of Hydropower Equipment | Bu L.-F.,Harbin Electrical Machinery Company Ltd | Hu J.-W.,Harbin Electrical Machinery Company Ltd
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

The vibration source of abnormal noise produced when water turbine unit 1# is running was investigated through vibration and noise tests of two Francis turbines in a certain hydraulic power station. The natural frequency of the penstock was tested at the butterfly valve floor by hammering method. It is found that when the load reaches above approximately 92 percent, certain hydraulic exciting frequency will couple with the natural frequency of the penstock and cause resonance phenomenon, which is the main cause of abnormal noise. Furthermore, the scheme of modifying the outlet edge of butterfly valve and adding guide plate to the man door of the spiral case was proposed. By improving the through-flow environment, the hydraulic exciting frequency was increased greatly and the energy of vortex was reduced. The method has very good effect on mitigating vibration. The research indicates that the expedite through-flow environment is of significance on avoiding resonance of structure caused by hydraulic excitation or vortex vibration.

Liang Y.-P.,Harbin University of Science and Technology | Chen J.-Q.,Harbin University of Science and Technology | Huang H.,Harbin Electrical Machinery Company Ltd
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2011

A 2-D transient finite element model of 1400MW nuclear half-speed turbogenerator was established in this paper. The rated operation condition of the generator was simulated using equivalent load impedance method which can avoid the iteration of the power factor. Aiming at the fact that the rotor of large-capacity nuclear half-speed turbogenerator was usually designed with bias slot to improve generator performance, the excitation current of the nuclear half-speed turbine-generator with different bias slot was calculated depending on the method's correctness. At the same time, the flux density change at critical points of high flux density region was quantitative calculated. The results showed that the bias slot structure of rotor will greatly influence the excitation current and reasonable bias angles will improve magnetic field distribution in high flux density region to avoid local overheating. The conclusion could provide theoretical basis for the rotor magnetic circuit structure design of large-capacity nuclear half-speed turbogenerator.

Jiao X.-X.,Harbin Electrical Machinery Company Ltd | Guan C.-W.,Harbin Institute of Technology | Li W.-L.,Harbin University of Science and Technology | Zheng P.,Harbin Institute of Technology
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2011

In order to research the influences of large turbine generator ventilating system on the stator cooling and stator temperature distribution, taking 200 MW turbine generator for example, the mathematical and physical model for 3D fluid and temperature coupling analysis of stator multipath ventilation system of half axial section was established. The fluid and temperature fields of motor with different cooling medium were coupled calculated using numerical method. The influence of hydrogen and air cooling capacity on temperature rise was quantitative analyzed. The influences of the changes of fluid properties on axial velocity distribution and inlet velocity of different ventilation ducts were analyzed. The heat transfer coefficients in fluid-structure contact surface were calculated. In addition to that, the temperature drop of stator insulation was analyzed, and the insulation temperature drop using hydrogen cooling is lower 13°C than that of using air cooling. It helps to reduce damages caused by stresses on insulation.

Wang C.,Harbin Institute of Technology | Li X.,Harbin Electrical Machinery Company Ltd | Jiang B.,Harbin Institute of Technology
Applied Physics Letters | Year: 2015

A model of plasma-antenna is carried out to study the radiation enhancement mechanism of antenna covered by thin plasma layer. The results show when the radiation intensity achieves maximum, a region of equal electric field is formed due to the reflection of electric field at the interface of plasma and air. The plasma layer acted as an extension of the antenna. Furthermore, the shape of plasma layer is changed to verify the effect of plasma boundary on antenna radiation. The study shows the effect of thin plasma layer on electromagnetic field and provides a type of plasma antenna. © 2015 AIP Publishing LLC.

Qingyu W.,Harbin Electrical Machinery Company Ltd
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2010

Characteristics of high lead bronze frictional ring and improvement of casting processing were described, including alkaline phenolic resin sand; metal mold casting and application of anti-tangent gating system. The practical production verified that the improved processing exhibits the features of simple programs, high precision and low cost as well as high efficiency. In addition, defects easily occurred in product and countermeasures were pointed out, which provided a reference for production.

Li Y.,Harbin Institute of Technology | Xing J.-W.,Harbin Institute of Technology | Lu Y.-P.,Harbin Institute of Technology | Yin Z.-J.,Harbin Electrical Machinery Company Ltd
IEEE Transactions on Magnetics | Year: 2011

Permanent variable transmission (PVT) is a new kind of non-contact power transmission device which has unique advantages for applying in the situations of airproof and small vibration requirements. As the most significant design data, static torque reflects the main transmitting capability of the PVT. Static torque expressions in a novel PVT based on the principle of magnetic permeability modulation were deduced with the energy method for the first time in this paper. Features of torques on low speed and high speed side with different pole pairings were analyzed. Above theoretical analysis was verified with FEM. A prototype with the adoption of the optimum design parameters was manufactured whose experimental results validated the theoretical and simulation analysis at last. © 2011 IEEE.

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