To research the impact of temperature-dependent characteristics of windings and magnets on the electromagnetic power loss and thermal properties of high-speed (HS) interior permanent magnet synchronous machines (PMSMs), an electromagnetic-thermal bi-directional coupling method (BDCM) is proposed for water-cooled HS PMSMs considering the assembling gaps between the motor components in this paper. The electromagnetic power loss is calculated by 3-D transient finite-element method and loaded into the 3-D temperature field according to the actual loss distribution, and the materials’ properties are in turn updated according to the temperature distributions. The loss and temperature calculation results of a 15kW HS amorphous metal PMSM are calculated by two different coupling methods in the conditions of the rated-load sinusoidal supply and converter supply, and compared with the measured results in the case of converter supply. The results obtained by the BDCM are more consistent with the experiment results, verifying the superiority of the proposed analyzing method in improving the calculation accuracy of motor loss and temperature rise. In addition, the applicable conditions of the proposed method are also summarized in the paper.

This paper presents the modified core loss calculation of the high-speed (HS) permanent magnet synchronous machines (PMSMs) with amorphous metal (AM) stator cores. In the initial stage of the HS PMSM design, the calculation of stator core loss is obtained according to the data of AM ribbon provided by the manufacturer, which causes a large error of AM core loss. So how to make the accurate calculation of the AM core loss with only the AM ribbon data from the manufacturer is impending in the initial and advanced design stages of HS PMSM development. In this paper, the characteristics of AM ribbon and AM stator core is measured and compared. According to the experimental results, the modified factor for the accurate calculation of AM core loss is obtained based on the loss characteristics of AM ribbon. Then, the no-load loss of a HS PMSM prototype with an AM stator core is analyzed by numerical methods and verified by experiments. The proposed modified factor of the AM core loss calculation can provide a reference for the design and analysis of HS AM PMSMs in the industry.

This paper proposes an analytical model for analyzing the electromagnetic performance of axial flux permanent magnet machines (AFPMMs) with the coexistence of static rotor radial deviation and angular eccentricity. Firstly, a quasi-3-D analytical model for the healthy AFPMMs is established using the scalar potential. Then, the analytical model of AFPMMs with the mixed eccentricity is derived by the coordinate transformation and air gap length function. The end effect under the mixed eccentricity is considered by an end coefficient, which improves the accuracy of back EMF by 1.3%. Based on the analytical model, the air gap flux density distribution, back EMF and cogging torque of AFPMMs with different rotor radial distances and angular eccentricities are calculated and compared with the corresponding results obtained by finite element analysis (FEA). The proposed model has higher analysis speed and less computer performance requirement than FEA with the similar accuracy. According to the results, the back EMF reduces obviously as the rotor radial deviation distance increases, and the back EMF increases slightly as the angular eccentricity becomes serious.

This paper proposes a novel analytical model which combines subdomain method and magnetic equivalent circuit (MEC) method to predict the no-load performance of V-shape interior permanent magnet (IPM) motors with any slot-pole combination considering the nonlinearity of magnetic bridges (MBs). The V-shape magnets are equivalent to the form of distribution along radial and tangential directions, and the motor is divided into two corresponding structures to facilitate the establishment of subdomains. To consider the saturation of MBs, the MEC method are employed to obtain the permeability of MBs to establish the boundary conditions. The no-load magnetic field of slotless motor can be obtained by solving the equations established by boundary conditions, and the conformal mapping is used to consider the effect of slotting. The proposed model can be used to calculate the no-load magnetic field, back electromotive force, and cogging torque of IPM motor. The results are verified by finite element analysis (FEA) and experiments, which confirms the validity of the model for facilitating the motor design and optimization. Compared with FEA, the proposed method has the advantages of faster modeling, shorter time consuming and meanwhile achieves the approximate accuracy. In addition, U-shape motors with MBs can also be analyzed by this model.

Aiming at the problem of long computation time of finite element analysis (FEA) and poor calculation universality of existing analytical models, this paper proposes a general hybrid analytical model to predict the no-load and load performance of interior permanent magnet motors with any slot-pole combination, where the form of magnet can be V-shape, U-shape or flat-shape. The magnets are equivalent correspondingly according to the rotor structure in the modeling process and the motor can be divided into eight types of subdomains, the no-load and load magnetic field of the motors can be obtained by solving the equations established by boundary conditions, where the nonlinear of core is calculated by local MEC. The proposed model can be used to calculate the air-gap magnetic field, no-load back electromotive force, cogging torque and electromagnetic torque of IPM motors with different rotor topologies. The effectiveness of the proposed model is verified by both FEA and experiments. Compared with FEA, this model can consume less time with the acceptable accuracy, which brings convenience to the design and optimization of related types of motors.