Advanced Materials Research Vols. 516-517

Abstract: The synchronously rotating vector components of the stator current isq and isd are controlled independently to control the torque and the rotor flux, respectively. It can be shown that rotor flux orientation in contrast to stator flux orientation tends to give true decoupling control. Within the synchronous current, the respective counter EMF (Electro Motive Force) signals can be added (or subtracted) to enhance the current loop response. The unit vector signal thetas that transforms the synchronously rotating stator voltage into stationary frame signals has been generated from the speed signal and slip signal which is a function of isq.

Abstract: This paper discusses the composition, structural features, working principle, and technical performance of a kind of motor torque measurement system. This system adopts two kinds of torque measurement methods, dynamic torque measurement method and static torque measurement method, uses microprocessor to collect data including rotational speed of load motor and torque signals of to-be-tested motor, figures out the rotational speed and torque through software algorithm, as well as displays and output them. This system also makes actual measurement of a type of motor. The measurement period is short; the measurement precision is high; and the performance is stable.

Abstract: This paper focus on a surface-mounted low-speed high-torque permanent magnet synchronous motor (PMSM) for progressive cavity pump wells. To minimize torque ripple, several methods is used such as proper pole-arc coefficient and fractional-slot windings. In the motor design, a non-linear finite element analysis (FEA) method is conducted to compute the performance of the motor. Through the simulation and experiment, the result shows that the design of low-speed high-torque PMSM is valid and presents a good performance.

Abstract: In a previous study, the authors have presented and developed a cylindrical traveling wave piezoelectric motor using a composite transducer. This study focuses the research on the wave deformation problems in the proposed stator. Firstly, the standing wave excited by the longitudinal vibration of the transducer is analyzed, and the vibration amplitudes of particles on the driving teeth are extracted to present the objective wave shape. Then, the wave deformation of the standing wave excited by the bending vibration of the transducer is analyzed. Finally, the longitudinal and bending PZT are excited together to gain a flexural traveling wave in the stator, and the vibration amplitude distributions in radial and circumferential directions are gained. Study result indicates that there are obvious deformations on the two standing waves, which cause the motion trajectories of the surface particles are inconsistent.

Abstract: This paper attempts to present an optimal design strategy and characteristics of high-power permanent magnet synchronous motor(PMSM). The structures of rotor lamination, calculation of Air-gap Length, how temperature influences the performance of the motor and the calculation of Xad、Xaq under the equivalent direct axis are presented.

Abstract: A misfire controller developed by the authors was used in this paper to investigate the effect of misfire on the emission and engine performance of a single cylinder motorcycle engine. Three kinds of test were carried out, the idle test, the engine dynamometer tests, and the chassis test. It was found that in the engine dynamometer tests, the concentration of unburned hydrocarbons in the engine exhaust was raised and the engine torque declined as the misfire rate increased. The variations of the CO and CO₂ are not the same in different operating conditions. At low load, CO concentration increased with the misfire rate while CO₂ moved in an opposite direction. Contrary condition happened at high load. The CO₂ concentration increased with the misfire rate while CO varied in the opposite way. Results of idle test showed that misfire would cause moderate deterioration of engine emission. However, chassis dynamometer test showed that even 1% of misfire would cause severe increase of emission.

Abstract: As the wide application of DC brushless motor in cars, this paper introduces a kind of motor design method that based on finite element theory. The motor electromagnetic simulation is analyzed by using finite element termed as Ansoft, the simulation results and experimental data are anastomotic, so the method is verified feasible. The motor in cars is restricted to the volume, the motor temperature index influence all basic parameters seriously, in this paper baseing on the motor loss simulate the motor 3D temperature distribution, and find out the highest spot, for designing the cooling system of similar motors provide instructional effect, and this is of important engineering significance.

Abstract: This paper introduces a vector control system for speed sensorless induction motor drive, which we have recently developed. In the introduce vector control system, one induction motor’s rotor speed estimation method based on model reference adaptive identification theory is proposed. The induction motor speed identification system based on the proposed method can estimate the rotor speed of the induction motor. The speed sensorless vector control system based on proposed method in this paper was built with Simulink blocks in Matlab platform. The simulation results indicate that the proposed method could operate stably in whole range of speed with preferable identification precision of rotor speed.

Abstract: The main problem for transformer protection is still how to identify inrush current. The inrush current is likely to occur when the transformer is closed with no-load or when the voltage recovers after fault. False operation may take place for the inrush current is big enough. This paper takes prony analysis as tool to fit the current waveform, and finds that there are two attenuation factors in asymmetrical inrush current’s aperiodic component, one attenuation factor in fault current’s aperiodic component, zero attenuation factor in symmetrical inrush current’s aperiodic component. It is necessary to point out that the two attenuation factors in asymmetrical inrush current are very different in value. Thus, it is possible to identify the inrush current through the number of aperiodic component’s attenuation factor. A large number of MATLAB simulation results prove the method.

Abstract: This paper analyses the characteristics and the glowing use value of LED lights, using STC series microcontroller design a system of LED which can automatically adjust the light according to the environment changes. The control system consists by the data acquisition module and control module and circuit driver module. This paper gives the control circuit hardware and software design. This system has many advantages such as energy conservation and environmental protection and longevity when compared with the conventional lighting system.