Applied Mechanics and Materials Vols. 313-314

Abstract: Aiming at the problem that the existence of the time varying parameter in the induction motor variable frequency speed regulation system influence the induction motor speed control performances through influences on the vector control decoupling performances, the author puts forward the solution that is to apply the adaptive inverse control scheme to the induction motor speed control system. Research findings suggest that adaptive inverse control is of high parameter robustness to both gradient parameter perturbation and mutational parameter robustness, which effectively reduces induction motor time varying parameters influences on dynamic and static performances of the frequency speed regulation system.

Abstract: To obtain the stable output voltage, a new type of MWD hybrid excitation generator is designed in which magnetic flux can be regulated from -2% to 22%. In the generator, hybrid excitation part and permanent magnet part work in parallel. This article introduces the working principle and structure of this generator. In addition, finite element analysis, magnetic field and regulation characteristics analysis for this generator is addressed to illustrate the variation of magnetic flux with pole length and excitation current changing. Experiments verify the design and finite element analyses.

Abstract: Aimed at optimizing electric radiators design process, the enterprises expectationsmanufacturing technologies and market developing status were analyzed, then electric radiators key design restraining factors were summarized, design orientation was proposed finally. Based on this premise, a block-based electric radiator design scheme was presented with the Design For Manufacture & Assembly method (DFMA), then taking electric radiators key structure and part as an example , the application of DFMA in design practice was discussed in the view of coordinating the relation of product styling effect and structure design. Practices show that DFMA method is beneficial to improve design efficiency and feasibility.

Abstract: For getting the High-performance electric vehicle control which has good dynamic, static characteristics and robustness, a direct torque control strategy of fuzzy sliding mode variable structure was designed to IPM motor. The method changes torque ripple, speed overshoot, poor anti-disturbance ability of the conventional DTC, and weakened the serious chatting which existed in sliding mode variable structure control. The simulation results show the feasibility and effectiveness.

Abstract: This paper proposes a bi-stable permanent magnetic actuator (PMA) for medium voltage vacuum circuit breaker. The structure of the proposed PMA is discussed and the optimization of the structure is carried out. The model of finite element analysis (FEA) is constructed where the flux distributions, electromagnetic force under different structure parameters are analyzed. The feasibility and correctness of the PMA are verified by the FEA simulation results and the optimal size for movable plunger and stationary iron ring is obtained.

Abstract: In order to study the impacts of the stator ventilation structure on the thermal performance, the fluid flow model of the stator radial ventilation ducts is established. The fluid flow fields are calculated and analyzed, from which the three-dimensional fluid field distribution inside the radial ventilation ducts is shown. Subsequently, the heat transfer coefficients are obtained on the basis of calculated results of the fluid flow field, and the stator three-dimensional temperature fields are solved. The numerical results are compared among different inlet velocities at the entrance of the radial ventilation ducts, which provides a theory basis for the design of the cooling system and improves the safe operation level of the generator.

Abstract: ts required to real-time detect rotor position for vector control of permanent magnet synchronous motor, the difference is initial rotor position angle between the output position signal of absolute rotary transformer and the position signal for park transformation, then it is necessary to get the initial position of the motor before the motor starts. Based on the characteristics of permanent magnet synchronous motor, a certain method about automatic detection of the initial position of a rotor is obtained. Compared with other methods, there are advantages such as simple calculation, small impact by the external and high detection accuracy. At last, the correctness of the method is verified by theory and experiment.

Abstract: This paper presents a method of reducing cogging torque of Permanent Magnet Synchronous Motor (PMSM) based on Finite Element Method (FEM). Cogging torque can be reduced by pole and slot number combination and the length of air gap reasonably. An investigation into the cogging torque in 4 pole, 48 slot and 6 pole, 54 slot interior-magnet machines with overlapping winding is described. The calculation results show that cogging torque can be reduced by nearly 50% by pole and slot number combination reasonably. Then influence of different length of air gap on cogging torque is also researched. Cogging torque can be weaken by increasing the length of air gap effectively, the smoothness of the motor running can be improved.

Abstract: This paper presents the modal analysis of stator and rotor in large capacity permanent magnet motor with exterior rotor. Modal analysis of motor has vital significant to suppress vibration and noise of the motor in operating. Models of stator and rotor in motor with exterior rotor are analyzed by finite element method. Calculation results of different models indicate that the laminations and windings in large capacity permanent magnet motor have substantial effect on natural frequencies and vibration shapes of stator of the motor. Magnets on interior surface in the exterior rotor have some influence on the modal of the rotor.