Applied Mechanics and Materials Vols. 416-417

Abstract: An exact analytical model of Halbach arrays permanent-magnet (PM) motor is established for the calculation of air-gap magnetic field on load in this paper. The exact analytical method is based on the resolution of Laplaces or Poissons equations by applying the boundary conditions on the interface between each sub-domain: air-gap, Halbach arrays and slots. The waveforms of no-load magnetic field flux density, back electromotive force (EMF), armature reaction field flux density, air-gap magnetic field flux density on load and electromagnetic torque, which computed by the analytical method were validated through the finite-element method (FEM).

Abstract: This paper deals with a low-speed high-torque six-phase fault-tolerant permanent magnet synchronous machine (PMSM) for wheel-driving electric vehicle (EV) applications. In machine design, winding arrangements and feasible slot/pole combinations are discussed and compared; a 24-slot/22-pole alternate-teeth-wound scheme is analyzed and designed. With reinforced slot-leakage component, the inductance of the machine is increased to restrain the one-phase short-circuit current to nearly 1.0 per unit preventing the machine from deteriorations in condition of that fault. The 24-slot/22-pole alternate-teeth-wound prototype machine is manufactured and the experimental verification is provided.

Abstract: A single-phase oscillating PM alternator is proposed for Free-Piston Stirling Engines. According to its sinusoidal kinetic characteristic, the design principle of this machine is proposed and on this basis, the finite-Element model is built. In the generator mode, the flux linkage, back EMF, voltage harmonics distortion ratio and thrust ripple are deeply analyzed. Due to the significance of the no-load back EMF, some structural parameters, like the permanent magnet thickness, the mover yoke thickness and the width of the tooth, are further optimized. After obtaining the optimal scheme, the electromagnetic performance of this single-phase oscillating PM alternator is investigated.

Abstract: Punch variety of drives, hydraulic, motor type is also commonly used. Conventional press drives both in terms of simplicity of the structure also in terms of effectiveness of control are present many problems. As is a background on the background of press drive innovative design, research on pulsed electric-magnetic field driven punch. Thanks to electro-magnetic direct drive, the system structure is simple, convenient control flexible, changing the timing and amplitude of excitation pulse, can change the speed and direction of movement of permanent magnet ring and have the output force of significant features. From the design on the effect of pulse electromagnetic drive punch, its index relative to the mechanical structure has improved, such as stamping frequencies up to 300 times/min, noise less than 80dB, volume reduction of cent, reduce the weight of 60%. This structure can greatly improve the working speed of the punch, while simplifying punch drive mechanical structure.

Abstract: Compared with double-sided permanent magnet linear synchronous motors (DPMLSM) with long secondary, the short secondary construction also has advantages of high dynamic performance and stable thrust, and is more suitable for the aspect of long-term acceleration. In this paper, magnetic field and characteristic of two different moving-magnet-type double-sided linear synchronous motors were analyzed by using 2D finite element method (FEM). The internal and external permanent magnet motor constructions with the same NdFeB and windings were compared according to flux density and electrical force. It was inferred that internal PM motors can provide the same force with lighter secondary weight and faster response speed.

Abstract: According to the problem of the optimization of cylinder linear motor,inspired by force balance relationship of the gravity center of a sand table,a new method of optimization algorithm is provided based on the adjacent relation between the global optimal and function center of gravity.In order to find the global optimum, introduction of filling control factors,through the function space center of gravity move,constructing a narrow range of neighborhood to make function center of gravity value gradually approximate optimal value.With the goal that the cylinder linear motor output thrust as large as possible,and at the time starting current as small as possible,using the center of gravity neighborhood estimation algorithm for the optimization.Test results show that the proposed algorithm is a kind of effective parameters optimization method.

Abstract: This paper presents a finite element investigation into the copper losses and rotor eddy current losses in brushless DC motors used in a flywheel energy storage system. The copper and rotor losses generate heat which needs to be dissipated in order to not exceed a defined temperature level for the magnet or winding insulation to avoid demagnetization or damage, which if it occurs will reduce the motor performance. The principle of operation and losses calculations are presented in the paper. The influences on the copper and eddy current losses are analyzed in detail, including the operation mode, the control strategy and the variation of the speed. Simulation and experimental results are presented and discussed.

Abstract: The ropeless elevator driven by linear motor is expected to be a new solution to vertical transportation of skyscrapers and the deep underground mines. Due to high thrust force density, low force ripple and low cost etc., a double-sided permanent magnet linear synchronous motor (DPMLSM) with slotted iron core and multi-segment primary is proposed and designed. Based on the erected 2D finite element model, the structure is optimized in order to reduce the detent force. Moreover, the influence of manufacture error on force performance is also investigated. It is shown the proposed DPMLSM is suitable for the ropeless elevator.

Abstract: This paper concerns the analysis and optimization of a permanent magnet linear synchronous motor. The motor consists of moving ironless coils and a stator with novel double-side Halbach array. Some characteristics of the linear motor were investigated. The dimensions of the novel Halbach magnet array were optimized. The optimization was verified by finite element method.

Abstract: This paper presents the modelling, design and testing of a short-stroke linear actuator to be embedded in a battery-powered positioning device. The particularity of this small (1 cm3) electromagnetic actuator is that it has to provide a constant force along its nominal stroke (1 mm), required by the specifications. In order to achieve this goal, an analytical and two Finite-Element-Method-based models have been developed. A genetic algorithm that takes the force profile into account is used to maximise the nominal thrust force of the actuator. The prototype shows a force profile that has less than 4% of deviation over the stroke and a nominal thrust force of 1.35 N.