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An analytical model is proposed for the prediction of electromagnetic quantities of slotted flux-reversal permanent magnet (FRPM) machines. Equivalent current theory is used to model the effects of permanent magnets (PMs), stator slots and rotor grooves. First, the stator slots and rotor grooves are nullified and the Poisson equation is solved in a slotless stator and cylindrical rotor machine. The effects of the stator slots and rotor grooves are then considered by injecting equivalent magnetization currents (EMCs) respectively on the stator slots wall and on the rotor groove edges. The PMs are also replaced by EMCs. Finally, the results of the proposed analytical model are verified by means of the finite element analysis. [ABSTRACT FROM AUTHOR]

This study presents a 2D analytical model for heteropolar active magnetic bearings. In this method, the problem is divided in to three subdomains: slots, slot‐openings and air‐gap regions. Initially, the radial and tangential components of the flux density vector are analytically presented in the absence of eccentricity. Then the impact of various amounts of eccentricity is investigated. Finally, the magnetic local traction and magnetic forces exerted to the rotor along x and y directions are calculated. The comparison between the proposed analytical model and the finite‐element method shows the efficacy of the model. [ABSTRACT FROM AUTHOR]

Brushless machines with interior permanent magnets (PMs) are mostly made with PM geometries inconsistent with the polar coordinates of the rotor cross section. Therefore, without any subdomain transformation, the analytical approaches cannot precisely model the interior PM machines in a single coordinate. This paper presents an accurate two-dimensional (2-D) analytical model for electromagnetic analysis of slotted brushless machines with rectangular spokePMs assisted by hub magnets. The slotting effect is modeled via subdomain technique. However, the spoke PM is not consistent enough with polar coordinates to be approximated by one subdomain. In order to map the spoke PMs in polar coordinates, herein, the rectangular geometry is approximated by a combination of arc shaped subdomains. On this basis, the 2-D analytic model is developed for M-fraction spoke PM. To verify the accuracy of the proposed 2-D approach, analytic results are compared with numeric results of finite elements method. It is revealed that by dividing the spoke PM into arc subdomains, the 2-D model achieves higher accuracy in calculation of electromagnetic quantities such as PM and armature reaction fields, electromagnetic torque, and back electromotive force. [ABSTRACT FROM AUTHOR]

This paper presents a 2-dimensional analytical model for external rotor brushless machines with surface mounted magnets. The subdomain technique is used to divide the problem into magnets, airgap, slot-openings, and slots regions. The magnetic flux density distributions are initially calculated, and then the important quantities of the machine such as back electromotive force, cogging torque, electromagnetic torque, self- and mutual-inductances, and unbalanced magnetic forces are computed. The finite-element method and experimental results are used to confirm the validity of the proposed model. [ABSTRACT FROM PUBLISHER]

In this paper, the electromagnetic torque, reluctance torque, inductance, and back-EMF are analytically calculated for brushless slotless machines with surface inset magnets. The calculations are based on the 2-D analytical magnetic field distributions. Although the expressions can be used for any magnetization patterns, the effects of three different magnetization patterns, i.e., radial, parallel, and Halbach, on the developed torque, back-EMF and inductances are examined. Besides, the influences of three types of armature current waveforms (sinusoidal, ideal rectangular, and six-step rectangular) on the mentioned quantities are investigated. The effects of pole arc per pole pitch ratio on the performance of slotless brushless machines are also studied. To evaluate the proposed 2-D analytical expressions, the analytical results are compared with those obtained by finite element analyses. [ABSTRACT FROM PUBLISHER]

Two techniques for the control of flux switching motors in the low and high-speed ranges of operation are presented in this paper. Because of the motor construction, torque production at some rotor positions is low, which leads us into not exciting the windings in those regions. Using this method will improve the efficiency by reducing the losses but, in high-speed range of operation there exist some aspects that affect the above technique. This paper introduces the proper control strategies for flux switching motors in low and high-speed ranges of operation, and presents the simulation results. The results that are obtained based on mathematical relations and not on computer aided simulations, show the advantages of the proposed control schemes. In order to verify the current relations, experiments were performed with similar conditions. The experimental results confirm that the current relations are adequate for control purposes. [ABSTRACT FROM AUTHOR]