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In this paper, an improved interpolating element-free Galerkin method (IIEFGM) with nonsingular weight function is introduced to calculate the magnetic field distribution of electrical machines. Since the shape function satisfies the property of the Kronecker-delta function, the IIEFGM can impose the boundary conditions directly. Meanwhile, the IIEFGM adopts a nonsingular weight function, which means the weight function of the conventional element-free Galerkin method (EFGM) can be used. In order to demonstrate the effectiveness of IIEFGM, the magnetic field distribution of a permanent magnet coreless disc machine is analyzed. The selection of weight function and the nodes distribution are discussed, the comparison with the finite element method (FEM) shows the IIEFGM has high computational accuracy.

Inductance characteristics play an important role in the output torque of the switched reluctance motor (SRM) whereas the windings connection form affects the mutual coupling between phases. According to the magnetic polarity models, dual-channel switched reluctance machine (DCSRM) with NNNSSSNNNSSS winding polarity is defined as DCSRMI, DCSRM with NSNSNSNSNSNS is defined as DCSRM2 and DCSRM with NNSSNNSSNNSS is defined as DCSRM3. Previous papers show that DCSRMs with different winding connections can offer different average torque, copper loss, iron loss and efficiency, but the work that different winding connections of DCSRMs running with channel fault is rarely carried out. This paper presents comparative studies of dynamic performance and magnetic characteristics of DCSRMs running with channel fault whereas only the winding connection type that differs. The frozen permeability method is adopted to compute static inductance and torque characteristics and to analyze the magnetic characteristics of the different winding connection models. The results show that the connection type of DCSRM3 can obviously enhance the average torque and minimize the torque ripple under the condition of channel fault. However the iron loss of DCSRM3 is highest among the three types under dual-channel excitation condition, which lowers the overall efficiency. By simulation analyses, a novel four-phase 16/12-poles fault-tolerant DCSRM called even-phase fault tolerance has been proposed. No matter in dual-channel excitation nor in single-channel excitation operation conditions, the performance of this even-phase DCSRM can be the best.

A novel electromagnetic clutch system is proposed to resolve the mechanical and electromagnetic impacts in the in-wheel motor drive electric vehicles. The dynamic analysis of the system is presented for researching the engagement process. Based on the dynamic analysis, the relationship between the action forces in the engagement is studied and the range of clutch's angular deflection is given for the design optimization of the clutch.

In-wheel motor system is recognized as the ideal drive system for electric vehicles. To reduce mechanical shock and electromagnetic impulsion brought by rigid connection between hubs and motor, our group proposed a novel permanent bistable electromagnetic clutch which flexibly connecting the motor and hubs. In this paper, several power supply schemes for the clutch are proposed and compared, then, pulsed power supply as a better scheme is further studied and optimal designed. Subsequently, the capacitance, charging voltage, coil turns and coil diameter are determined. Finally, experiments verified the power supply system we proposed.

A novel bistable permanent electromagnetic clutch (BPMEC) unit is proposed which can be used in electric vehicles to fulfill flexible connect the motor and hubs. The magnetic field distribution of the clutch is predicted by using finite element method and magnetic circuit method. Subsequently, the main sizes are optimized by investigating flux leakage coefficient, and micro-topology of BPMEC is optimized by investigating magnetizing current.

Induction machine with indirect vector control system has advantages of simple structure and high performance. But under the condition of parameters deviation, both steady-state and transient performance of this system are influenced. The succeeding section of this paper analyses the effect of parameters deviation for indirect vector control system. Then a slip frequency correction method is proposed in the following section to minimize error of rotor flux position and improve the system's robustness to parameters changing. The results of this paper give some reference to the design of indirect vector control system with considering parameters deviation.

By using clutch for replacing rigid connection with a flexible one between hub and wheel-motor, a novel solution for in-wheel drive is proposed with the possibilities of ‘no-load starting and variable-idle clutching’ together in this paper. It is then important to choose suitable idling speed of wheel motor for assuring drive comfort from a standing start in direct-drive electric vehicle. Based on the actual load torque, the control strategy of optimal idling speed is discussed in the aim of enhancing drive comfort and reducing electromagnetic impulsion.

A novel bistable permanent magnet electromagnetic clutch (BPMEC) unit is introduced into wheel drive so as to turn rigid connection between hub and motor into flexible form, thus remit mechanical and electromagnetic impulsion. Working principle of this idea is conceptually demonstrated. Electromagnetic relations of the BPMEC unit are presented, as well as performance calculated and verified by experiments measured on a prototype. Finally, general design principles are investigated in detail by studying leakage coefficient which is obtained from analytical solution.

Clutch is widely adopted in fuel vehicles, but it is rarely found in in-wheel motor driven electric vehicles. This paper proposes a general formula to solve the electromagnetic force and provides a clutch system for the newly designed bistable permanent magnet (PM) electromagnetic clutch in wheel hub motors based on the formula.

This paper presents a simplified fuzzy logic based speed control scheme of an interior permanent synchronous motor (IPMSM). The proposed FLC is designed based on conventional max torque per ampere below the rated speed and flux weakening control above the rated speed. The simplified fuzzy logic controller is suitable for real time implementation because of the less computational burden. The application MATLAB Simulink was used for simulations of the FLC based IPMSM drive. The efficacy of the proposed simplified fuzzy logic controller base drive of the IPMSM with flux weakening is verified by the simulation.

The new type of ALA+SPM rotor synchronous machine is made of a surface permanent magnet (SPM) part and an axially-laminated anisotropic (ALA) reluctance part separately mounted on the same shaft. The displaced angle between the two parts d-axes has important influence on the motor performance, maximum load capacity of the hybrid rotor machines with different displaced angle was researched based on U/f = constant control in this paper, the results show that the hybrid rotor machine with reasonable displaced angle can obtain strong load capacity.

This paper deals with 3-D temperature estimation for the squirrel-cage induction motor under rated load conditions, and it employs finite-element method to analyze the thermal fields. The 3-D temperature model (including stator and rotor) of the induction motor is established, and by analyzing the electromagnetic field of the induction motor, the loss distribution can be obtained, including rotor loss, iron loss, copper loss, and so on, which are taken as the heat source in thermal field analysis. The theoretical predictions are verified by direct comparison with experimental results.

Novel transverse flux permanent magnet motor (TFPMM) with Brushless DC drive is expected to be applied to direct-drive electric vehicles. To reduce torque ripple and obtain faster torque response, direct torque control (DTC) with position sensors instead of flux linkage observer has been employed. The voltage vectors are determined by position of magnetic poles as well as torque hysteresis comparator. In consideration of much longer commutation process caused by the features of novel TFPMM, phase advance commutation has been brought in DTC to achieve maximum torque per ampere. Simulation results have been presented to verify the effectiveness of the proposed method.

Back EMF zero crossing detection method has been successfully applied to sensorless control of conventional brushless DC motor. This paper highlights the differences in its implementation for novel transverse flux permanent magnet motor (TFPMM), as regards additional detection error. The reasons for long commutation process in novel TFPMM have been discussed to indicate much wider voltage spikes, which is the essence of additional detection error. It has been also shown from experimental results that the zero crossing point of filtered phase voltage is ahead of that of corresponding back EMF. To determine the phase compensation for rotor-position-detection error, the corresponding phase difference is presented under varying load torque conditions.

This paper introduces a permanent magnet synchronous torque motor with an external rotor, and provides the design and optimization of its electromagnetism and structure. Firstly, the basic structural features of this motor are described. In order to make the motor more compact and have higher power density, an improvement of cooling structure is made. Next, the method is determined and the program is compiled for electromagnetic computing, and the finite element analysis on magnetic circuits is conducted by applying ANSYS. Finally, by making the model and testing, the rationality of the design is verified.

The axially laminated anisotropic (ALA) rotor motor is a competitive candidate for high performance variable speed drives. However, the online startup of the motor is not applicable for lacking of starting cages. In the inverter-fed applications, in order to keep the synchronism between the rotor and the flux, a sensor is always required to detect the position of the rotor. But the utilization of sensor will increase the cost and deteriorate the stability, or even be forbidden in some applications. In this paper, the direct torque control (DTC) scheme is employed to control the ALA rotor motor. The characteristics of basic DTC scheme are stated and the discrete space voltage vector modulation (DSVM) is introduced. Finally, the experimental investigation on a DSP-based drive system is presented. It's validated that the motor with the proposed control strategy has satisfactory starting and operating performance.

Novel planar and spatial bending embedded shape memory alloy actuators are depicted firstly. The actuators are mainly made up of room temperature vulcanization silicone elastic rods with several axial or bias embedded SMA wires. The operating principles of actuators are discussed in detail as well as the practical specifications of prototype are determined depending on optimized design of the configuration parameters. Moreover, precise and practical shape analysis models calculating martensite fraction using two exponential equations for heating and cooling respectively are reached to overcome the inherently non-linearity arising from the nature of shape memory effect. Finally, an anthropomorphic flexible three-fingered robot hand making use of planar and spatial bending ESMAAs is developed

The axially laminated anisotropic (ALA) rotor motor has many advantages over the conventional counterparts. However, the startup process of the inverter-fed prototype presents severe oscillation and asynchronous operation. To improve the startup performance, an additional mechanical damper is mounted on the shaft of the rotor. Once the oscillation occurs, the damper puts into effect. A reverse damping torque is then applied to weaken the oscillation and ensure the synchronism. By using this method, the startup performance of the motor is remarkably improved and the load capability is enhanced as well. To find out the cause of the oscillation, the small disturbance approach is applied to the dynamic model. The synthesis reveals that the poor electromagnetic damping is the critical factor resulting in instability, due to the lack of damping windings on the rotor. To reinforce the stability, the combined systematic damping factor should be increased. In addition, the effects of the mechanical damper on motors with different saliency ratios are discussed. Finally, the experimental results are presented to verify the theoretical analysis and design purpose.

The stresses in pulsed magnet are calculated with a pulsed magnet design software (PMDS) package developed with Visual Basic 6. Stress model includes elastic and plastic deformation. The solution is given by Hooke's law and total strain theory. Prototype of 70 T coil was made. The coil windings were composed of two sections. In the inner section, four CuNb conductor layers were reinforced independently with Zylon epoxy composites. In the outer section, four soft copper layers were insulated with glass fibre and reinforced with a thick carbon layer. The thickness of reinforcing layers was optimized to distribute the strength evenly throughout the coil. Calculation indicated the stress in the coil was below the UTS (ultimate tensile strength) of the materials. In experiment., it survived at 70 T field