Control and operation of a new 8/6-pole split-winding doubly salient permanent magnet motor drive

This paper proposes a new 8/6-pole split-winding doubly salient permanent magnet (DSPM) motor drive. The analysis, control, implementation and experiments of the motor drive are presented. The magnetic field analysis is carried out using a finite element method. The split-winding topology is proposed to extend the constant power operation range. The control strategy for the DSPM motor drive is developed. Two operation modes, namely 4-phase and 2-phase operation modes, are proposed for the 8/6-pole DSPM motor drive. In 4-phase operation mode, a half-bridge power converter but without split capacitors is used to reduce the number of power devices and to eliminate the problem of voltage unbalance in the capacitors. The drive system is implemented and tested. The experimental results show that the developed control scheme can operate the DSPM motor properly, and the DSPM motor drive offers high efficiency over a wide power range and good dynamic performance. Furthermore, the 2-phase operation mode of the 8/6-pole DSPM motor offers the potential of eliminating the torque ripple of the motor drive.published_or_final_versio

Properties of nuclei in the inner crusts of neutron stars in the relativistic mean-field theory

We study the properties of nuclei in the inner crusts of neutron stars based on the Boguta-Bodmer nonlinear model in the relativistic mean-field theory. We carefully determine the surface diffuseness of the nuclei as the density of matter increases. The imaginary time step method is used to solve the Euler-Lagrange equation derived from the variational principle applied to the semiclassical energy density. It is shown that with increasing density, the spherical nuclei become more neutron rich and eventually merge to form a uniform liquid of neutrons, protons, and electrons. We find that the smaller the value of the incompressibility K, the lower the density at which the phase transition to uniform matter occurs. The relativistic extended Thomas-Fermi method is generalized to investigate nonspherical nuclei. Our results show that the spherical nucleus phase is the only equilibrium state in the inner crusts of neutron stars.published_or_final_versio

Static characteristics of a new doubly salient permanent magnet motor

In this paper, magnetic field analysis of a new doubly salient permanent magnet (DSPM) motor is carried out based on the finite element method (FEM). Hence, the corresponding static characteristics, including PM flux-linkage, self-inductance and mutual-inductance, are deduced (the interaction between PM field and armature field are taken into account). A method for measuring the motor inductance is newly proposed. The theoretical analysis is verified by experimental results.published_or_final_versio

Nonlinear magnetic circuit analysis for a novel stator-doubly-fed doubly-salient machine

published_or_final_versio

A new doubly salient permanent magnet motor

In this paper, a new 8/6-pole doubly salient permanent magnet (DSPM) motor is proposed and analyzed. The key is to analytically derive the output power density of the DSPM motor in terms of the rotor-to-stator pole ratio. Hence, the analytical design, finite element analysis and computer simulation of the proposed 8/6-pole DSPM motor are presented. The results show that this DSPM motor has following major features: it can achieve higher power density than an induction motor; its power density is proportional to the ratio of rotor pole and stator pole numbers; there is a maximum speed limitation which is proportional to the voltage but inversely proportional to the phase winding turns and the rate of change of PM flux; at high speed, the distribution of phase current is asymmetric and current regulation is needed in the negative stroke. Compared with the well known 6/4-pole DSPM motor, the proposed 8/6-pole one offers higher power density, wider speed range and less phase current magnitude.published_or_final_versio

Some scheduling problems with deteriorating jobs and learning effects

Author name used in this publication: T. C. E. Cheng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Static characteristics of a new doubly salient permanent magnet motor

In this paper, magnetic field analysis of a new doubly salient permanent magnet (DSPM) motor is carried out based on finite element method (FEM). Hence, the corresponding static characteristics, including PM flux linkage, self-inductance, mutual inductance, and static torque are deduced (the interaction between the PM field and armature field are taken into account). New methods for measuring the motor inductance are also proposed. The theoretical analysis is verified by experimental results.published_or_final_versio

Nonlinear varying-network magnetic circuit analysis for doubly salient permanent-magnet motors

In this paper, a nonlinear varying-network magnetic circuit (VNMC) modeling method is developed for doubly salient permanent-magnet (DSPM) motors. The method is used to analyze the static characteristics of DSPM motors by specific permeance calculations, in which the interaction between the permanent-magnet field and the armature current field, as well as magnetic saturation, are taken into account. Two newly proposed DSPM motors (12/8-pole and 6/4-pole) are used as examples. There is good agreement between the results of the nonlinear VNMC modeling method and finite-element analysis. Moreover, the nonlinear VNMC method offers the advantage of calculating, effectively and efficiently, the static characteristics of DSPM motors having different dimensions, parameters, and conditions. Finally, the proposed method is verified by experimental testing of a 6/4-pole prototype. © 2000 IEEE.published_or_final_versio

Nonlinear magnetic circuit analysis for a novel stator doubly fed doubly salient machine

A novel stator doubly fed doubly salient (SDFDS) machine is proposed, and a nonlinear magnetic circuit (NMC) model is developed for the analysis of the SDFDS machine. Based on the NMC model, the static characteristics of an 8/6-pole SDFDS machine are analyzed using specific permeance calculations, in which the interaction between field and armature currents as well as the magnetic saturation are taken into account. The proposed NMC modeling is verified using both finite-element analysis and experimentation.published_or_final_versio

New split-winding doubly salient permanent magnet motor drive

A new split-winding doubly salient permanent magnet (DSPM) motor drive is proposed. This DSPM motor drive offers the advantages of high power density, high efficiency, and wide speed range. The corresponding operation, analysis, implementation, and experimentation are successively presented. Finally, experimental results are used to confirm that the proposed DSPM motor drive offers high efficiency over a wide output power range, exhibits good dynamic performance, and extends the constant-power operation range significantly.published_or_final_versio