Applied Mechanics and Materials Vols. 416-417

Abstract: This paper proposes a new linear fault-tolerant flux-reversal permanent-magnet machine for urban rail transit. The key of the proposed machine is that the magnetizer divides the short mover into two modules. As a result, the two modules of the short mover have the complementary magnetic circuit, and the detent force of the proposed machine is reduced. Also, it possesses more symmetrical and sinusoidal back electromotive force (back-EMF). In addition, the mutual inductances of the propose machine are much lower than the self-inductances, hence offering fault-tolerant capability. The finite-element results confirm the validity of the proposed machine.

Abstract: Wind energy is being widely developed to replace the fossil energy and protect the environment against pollution. This paper proposes a novel dual-rotor radial flux permanent-magnet (DRRFPM) wind turbine with the toroidally-wound windings which can apparently improve the utilization coefficient of wind energy. Two concentric surface-mounted PM rotors are located inside and outside of a cup stator with back-to-back windings, respectively. The configuration, features, and design principle of the proposed machine are introduced. The magnetic circuit approach is used to analyze the machine with a simplified motor topology. To verify the accuracy of the present model, two-dimensional finite element method (FEM) is conducted for the modeled machine to validate the characteristics and performances of the proposed DRRFPM wind turbine.

Abstract: Inductance and flux leakage are important parameters in determining steady-state and transient performance for multi-segmented permanent magnet (PM) linear motor, especially that in pass-through section. This paper investigates inductance characteristics considering asymmetrical phase components when the mover departs from one section, and corresponding testing method are discussed. Meanwhile, PM flux leakage is calculated from electromotive force waveform (EMF) in no-load test, and its special harmonics in pass-through section should be focused on. Finally influences of inductance and PM flux linkage variation on current response and thrust ripple are presented by equivalent circuit. The accuracy of solutions is validated by combined simulation model.

Abstract: Cogging torque is one of the main reasons which cause ripple in motor's speed and torque. So the reduction of cogging torque must be considered in the design of permanent magnet machines. There are many existing techniques for reducing cogging torque in PM machines. This paper presents a new optimal method for cogging torque minimization by magnet shifting in disc-type PM machines. The impact of magnet shifting on cogging torque and torque output are discussed in disc-type PM machines. In order to reduce the cogging torque effectively while without being harmful to the average torque output. This paper used genetic algorithm (GA) to calculate the shift positions combined with slot-opening optimization to achieve the minimum cogging torque.

Abstract: In order to minimize the detent force of permanent magnet linear synchronous motor (PMLSM) caused by end effect, a novel auxiliary poles one-piece structure is proposed. Two auxiliary poles are extended directly from two ends of the armature core. And magnetic isolation bridges are set between auxiliary pole and armature core. Compared with the conventional discrete auxiliary poles, the one-piece structure will reduce the manufacture difficulty of PMLSM with auxiliary poles and improve the reliability of linear motor.

Abstract: This paper presents the performance analysis of a linear synchronous motor which employs high-temperature superconducting (HTS) bulk magnets on the mover and normal copper windings on the stator. The linear motor is designed to drive a prototype HTS maglev vehicle in which the mover is suspended by the levitation force between HTS bulks on the mover and permanent magnets on the ground. Finite element magnetic field analysis is conducted to calculate the major parameters of the linear motor and an equation is derived to calculate the electromagnetic thrust force. Theoretical calculations are verified by the measured results on the prototype.

Abstract: A new frog-leg winding permanent-magnet (PM) brushless DC motor is proposed in this paper. Besides PM excitation and electric commutation, the motor has a type of mesh winding inherited from the conventional brushed DC motor. With the aid of a position sensor, the new motors operation principle is basically as same as the brushed one. Based on the frog-leg winding configuration of simplex lap and duplex wave, the motor is designed with 4 poles and 22 slots, and the number of phases is set as 11. Furthermore, an exact analytical method for predicting the instantaneous magnetic field, electromotive force (EMF) induced in the armature winding, cogging torque and output torque of the new motor is introduced. Results from this analytical method are compatible with corresponding finite element analyses (FEA).

Abstract: This paper concerns the local reduction of the magnetic flux density by means of magnetic shielding. Using a spatial frequency description, a 2-D semi-analytical periodic model is obtained for a coreless single-sided linear permanent magnet motor. The magnetic shield is included in the modeling using mode-matching. The obtained magnetic flux density is compared to a finite element model and is verified with measurements. The results show a reasonable agreement between the semi-analytical model and the measurements. Some large deviations occur due to the modeling assumption that the shield has a linear permeability, while the used shields are saturated. However, the semi-analytical modeling method is accurate enough for design purposes and initial calculations, especially when being aware of the possible saturation of the shield.

Abstract: In this paper, a cage rotor induction machine is designed according to the demand of Beijing Automotive New Energy Automobile Limited Company. The design results of the stator and rotor are given, which is verified by simulation, and the induction machine is manufactured. Then the induction machines control diagram is given and the controller is manufactured. This system is assembled in the EV, and the debugging tool of Vector CANalyzeris introduced. The experiment results of vehicle road test show that the induction machine and its controller designed could meet the demands of customer.