Jiang Xintong

Theoretical and Simulation Analysis of Influences of Stator Tooth Width on Cogging Torque of BLDC Motors

Cogging torque reduction is one of the most important requirements in the design of BLDC motors due to its direct impact on the performance of the motor. In this paper, the influences of tooth width and slot/pole match on cogging torque corresponding to both uniformed teeth and nonuniformed teeth were theoretically analyzed on the basis of analytical expressions of cogging torque deduced with energy method. Furthermore, several models which denote features of different slots and poles were setup and calculated in finite element analysis software Flux2D, the result of which verified the theoretical analysis. Valuable conclusions and some suggestions were given in the paper which is meaningful to the design of good performance BLDC motors.

A simplified testing method of copper loss and its temperature raise for multiunit propulsion permanent magnet synchronous motors

Large power low speed Permanent Magnet Synchronous motors are more and more widely used in propulsion areas. Their tests are relatively more inconvenient because some special and large power equipments are needed. In this paper, according to the features of multiphase and multiunit for these kinds of motors, a novel and simplified testing method of copper loss and its temperature raise is brought out. With a special control tactics, the needed characteristics were obtained without any additional equipment. The method is proved to be more practical in engineering testing.

Analysis of radial electromagnetic force under different poles/slots matched in large torque PMSMs

Vibration and noise reduction is one of the most important requirements in the design of PMSM due to its direct impact on service life and operating stability. The radial electromagnetic force acted on the rotor is a major factor of a PMSM influencing on its vibration and noise. In this paper, the distribution characteristics of radial electromagnetic force were theoretically analyzed on the basis of FEM method in Ansoft, simulation analysis of radial electromagnetic force corresponding to different slot/pole structures was carried out, and test of direct-driven large torque PMSMs was presented to validate the theoretical analysis. The conclusion has a good meaning to optimum design of these motors.

A new Flywheel Energy Storage System (FESS) Using Z-Source Inverter

This paper presents a Flywheel Energy Storage System based on the Z-source inverter with maximum boost control. The proposed system can boost and generate a desired output voltage efficiently when low voltage of the generator is introduced due to the low flywheel speed. Z-source inverter has been identified to exhibit both voltage buck and boost capabilities in steady-state. In order to provide the required voltage and power, the maximum boost control is used in the proposed system. Z-source inverter, which is used in Flywheel Energy Storage System, is modeled and simulated using MATLAB/SIMULINK.

Electrical-thermal coupled calculation of a submersible motor used for deep-sea electromagnetic propeller

With the rigorous requirements of high power density for propulsion system, an oil-filled PMSM used for deep-sea electromagnetic propeller was investigated in this paper. The heat sources in motor, including copper loss, stator iron loss and viscous power loss, were estimated, and especially the influence of temperature on power losses was also discussed in experiment. And then the heat transfer coefficients including the surface of the shell, and the gap filled with oil were proposed on the basis of analyzing of flow field. Finally, a 3D FEM thermal model was set up to compute the temperature distribution taking into account the electrical-thermal coupled calculation.

Permanent magnet generator 3D transient temperature field analysis based on magnetic-thermal element coupling algorithm

In the past, the stator core loss was considered as a whole or sub-blocks heat source in the temperature field calculation, while the actual loss was distributed throughout the core. Consequently, this approach resulted in calculation error. To reduce the error, a magnetic-thermal element coupling algorithm is presented. Elements loss, calculated in 2D magnetic field by using FEM, is coupled to the corresponding 3D element to calculate transient temperature field. Let us take permanent magnet generator for example. A transient temperature field analysis is carried out by using the magnetic-thermal element coupling algorithm.

Simulation analysis of steady state characteristics of parallel-axis permanent magnetic gear

The steady state characteristics reflect the main transmitting capability of the permanent magnetic gear (PMG). The static and following-up characteristics of the parallel-axis PMG were analyzed with the help of Flux2D. The simulation result of static torque validated the feasibility of the structure of the parallel-axis PMG. During the process of actual operating, the driving torque on the passive part was a fluctuating quantity and the fluctuation amount is directly related to the starting angle of the active part.

Influence of axial length ratio of stator segment on performance of tubular transverse flux linear machine

In this paper the influence of axial length ratio of stator segment on performance of tubular transverse flux linear machine (TTFLM) is investigated. The following issues have been emphasized: cogging force, winding flux, and back-EMF. The special topology of TTFLM requires 3-D finite element analysis to accurately predict the machine performance. However, equivalent 2-D finite element analysis is performed, which is more visual from physical view and faster from computing time than 3-D finite element analysis.

Influence of rotor tooth shape on air-gap magnetic field in Homopolar Inductor Alternator

A simplified 2D computed model is presented in order to investigate the influences of the geometry parameters of rotor tooth on the air-gap magnetic field of Homopolar Inductor Alternator (HIA) by using Finite Element Method (FEM). The results show that the fundamental air-gap flux density depends on the width and height of the rotor tooth. Given that the polar pitch in HIA is 90° mechanical angle, a more sinusoidal field distribution is obtained when the rotor tooth width is equal to 40°angle. And a lager fundamental component of the air-gap flux density is yielded when the rotor tooth height is at least 16 times long than the air-gap radial length.