Air-gap Permanent Magnet Research Articles

Dual three Phase Operation of Dual Airgap Permanent Magnet Vernier Machine Having a Yokeless Rotor

Dual three Phase Operation of Dual Airgap Permanent Magnet Vernier Machine Having a Yokeless Rotor

Cost-Effective Design of Dual Airgap Permanent Magnet Vernier Machine Having a Yokeless Consequent Pole Rotor

Cost-Effective Design of Dual Airgap Permanent Magnet Vernier Machine Having a Yokeless Consequent Pole Rotor

Torque Ripple Suppression of Flux-Switching Permanent Magnet Machine Based on General Air-Gap Field Modulation Theory

Compared with the conventional permanent magnet (PM) machines, the flux-switching permanent magnet (FSPM) machine exhibits higher torque ripple due to its special doubly salient structure and high air-gap flux density, leading to the deterioration of smooth operation. In this article, the output torque ripple suppression methods of FSPM machines from both rotor and stator sides are proposed with the aid of general air-gap field modulation theory. According to harmonic modulation mechanism, air-gap PM field can be modified by revising harmonic content of rotor and stator modulation functions and, consequently, three concepts, including cos-shaped edge rotor (CSER), cos-shaped edge stator, and double cos-shaped edge, are proposed and implemented to suppress the output torque ripple due to the cogging torque and electromagnetic torque ripple of FSPM machines. Finally, finite-element analysis and experiments are conducted to verify the proposed approaches. The results reveal that the CSER method exhibits the most effective suppression effect.

Analytical Investigation and Heuristic Optimization of Surface Mounted Permanent Magnet Machines With Hybrid Magnetic Structure

Cogging torque causes major operational setbacks for Permanent Magnet (PM) machine operation, particularly in applications where a quiet performance is desired. This paper presents a heuristic optimization framework to optimize the cogging torque in Surface Mounted Permanent Magnet (SPM) machines consisting of a hybrid magnetic structure (i.e., rare-earth and ferrite magnets). To avoid excessive computational time and volume associated with Finite Element (FE)-based optimization solutions, analytical approach is paired up with the optimization algorithm to determine the optimal design while FE is utilized for verification and validation purposes. First, analytical expressions are established for individual objective functions (i.e., airgap PM flux distribution, and cogging torque), and their corresponding spatial harmonics are identified using the air-gap field modulation theory. Next, the presented analytical model is utilized to optimize the system (i.e., minimize the cogging torque) to the desired target level via two different solutions (i.e., Genetic Algorithm (GA) and Particle Swarm Optimization (PSO)), and their respective performance are compared. To determine the efficacy of the presented solutions, the optimal hybrid machine response is compared against the baseline structure.

Parameter design and characteristic analysis of the interior non-uniform airgap permanent magnet synchronous motor for electric vehicle

Parameter design and characteristic analysis of the interior non-uniform airgap permanent magnet synchronous motor for electric vehicle

Parameter design and characteristic analysis of the interior non-uniform airgap permanent magnet synchronous motor for electric vehicle

Aiming at the demand for high torque and wide speed range of permanent magnet synchronous motor (PMSM) used in electric vehicles, a PMSM with fractional slot concentrated winding and the rotor of non-uniform airgap is designed. Fourier harmonic analysis theorem is used to calculate the harmonic content and peak value of cogging torque of different rotor eccentricities. Combined with finite element simulation software, the influence of rotor of uniform airgap and the rotor of non-uniform airgap on the q axis and d axis magnetic circuit is analysed respectively, so the optimal rotor eccentricity is determined. Compared to the rotor of uniform airgap, the peak value of cogging torque and the waveform distortion rate is reduced, while the salient rate is increased. Performance test is done and results show that reasonable rotor eccentricity can effectively improve the motor of flux weakening capability and widening the operation region of high efficiency.

Analysis of Air Gap Permanent Magnet Eddy Current Coupling of the Equivalent Magnetic Charge Method Based on Field

Analysis of Air Gap Permanent Magnet Eddy Current Coupling of the Equivalent Magnetic Charge Method Based on Field

Optimal design of cylindrical air-gap synchronous permanent magnet couplings

Different types of structures for ironless synchronous cylindrical air-gap permanent magnet couplings are studied. In these structures, radially and tangentially oriented magnets are placed in ironless cores. The structures present a very small inertia and offer important benefits in many cases. An efficient method to calculate the torque of these types of couplings is presented. It is based on analytical formulas for the forces between parallelepipedical magnets. Optimal designs for each type of coupling and each number of pole pairs are determined by using a nonlinear optimization method. The design results are analyzed. The different types of structure are compared. The influence of the number of pairs of poles and of the main characteristic dimensions of each coupling is discussed. The results show that an ironless coupling structure where both radially and tangentially oriented magnets are used is a very advantageous solution.

Instantaneous magnetic field distribution in permanent magnet brushless DC motors. IV. Magnetic field on load

For pt.III see ibid., vol.29, no.1, p.143-151 (1993). An analytical technique is developed for predicting the instantaneous magnetic field distribution in the airgap-permanent magnet region of radial-field topologies of brushless DC motors equipped with a surface-mounted magnet rotor and operating under any specified load condition. It accounts implicitly for the stator winding current waveform and the effect of stator slot openings. The 2-D field analysis, in polar coordinates, combines the armature reaction field component, derived from an analytical determination of the relative temporal and spatial position of the two field components. The predicted open-circuit, armature-reaction, and load field distributions all show excellent agreement with results from corresponding finite element analyses.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>