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This paper presents a fast analytical model for estimating the components of the PM flux density distribution in the air-gap for a number of interior permanent magnet synchronous machines (IPMSMs). Deriving the two-dimensional (2-D) analytical model for IPMSMs is more challenging compared to that of surface-mounted permanent magnet synchronous machines (SPMSMs) due to the inconsistent geometry of the rotor in polar coordinates. IPMSMs are usually modeled by using 0-D or 1-D methods such as the magnetic equivalent circuit (MEC); however, the MEC method is unable to take into account the tangential component of the magnetic flux density vector. In this paper, a 2-D analytical no-load electromagnetic model for five rotor topologies of IPMSMs is proposed. The effects of the stator slots on the radial component of the PM flux density distribution in the air-gap are then included by defining an air-gap function. The effects of the stator slots on the tangential components of the PM flux density distribution in the air-gap are also considered by injecting virtual surface currents (VSCs) or virtual permanent magnets (VPMs). For verification purposes, the analytical results are compared with those of the finite element method (FEM) and the experimental results of one of the cases. [ABSTRACT FROM AUTHOR]

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]

In this work, an analytical technique is developed for modeling of the air gap flux density in the slotless eccentric surface-mounted permanent magnet (PM) machines. In the developed model, a 2-D solution for the Poisson equation is provided. In the modeling process, the eccentric stator is replaced with an equivalent current sheet at the stator bore. This current sheet is selected such that the overall tangential flux density caused by the PMs and the current sheet at the removed stator bore is zero. To find the contribution of current sheet on the air gap flux density, a conformal transformation is applied. The obtained exact values of the instantaneous air gap flux density components are used to compute the variables of the eccentric machine such as the back-EMF, the electromagnetic torque, and the unbalanced magnetic force. The provided model is valid for static, dynamic, and even mixed rotor eccentricity conditions. Finally, finite-element analysis is applied to verify the proposed model. [ABSTRACT FROM PUBLISHER]

Abstract—In this work, an electromagnetic design procedure for a line-start synchronous reluctance motor is presented, and the main considerations are highlighted. To improve the steady-state performance of this motor, the geometry of the flux barriers as well as their number are optimized using an automatic optimization algorithm. For this purpose, two types of flux barriers, arc shaped and trapezoidal shaped, are formulated and studied by finite-element analysis. Analyzing the average cage torque during synchronization, effectiveness of the dq-axis rotor resistances on successful synchronization is discussed. To validate the results of this analysis, dynamic simulations are used, and the impact of the dq-axis rotor resistances on synchronization is investigated. In addition, the effect of the rotor bar position on the value of the dq-axis rotor resistances is discussed and analyzed by finite-element analysis. Finally, the impact of small pieces of permanent magnet in the flux barriers is studied. It is shown that against the permanent magnet-assisted motor, permanent magnets always enhance the motor performance; the steady-state characteristic of the line-start permanent magnet assisted motor could be deteriorated by permanent magnet. [ABSTRACT FROM PUBLISHER]

This paper compares two methods to compute the parameters of a line-start synchronous reluctance (LSSR) machine, by means of finite element analysis. In both methods, both the impact of the skin effect on the rotor parameters and the impact of saturation on magnetizing inductances are taken into account. The first method is based on an equivalent single-phase model of the machine. A pulsating flux is imposed along the d- and q-axes separately, so as to compute the machine parameters along both d- and q-axes. Magnetizing inductances are achieved as a function of the flux, and the rotor resistances and leakage inductances are obtained as a function of rotor frequency. The second method is based on the d-q axis model of the LSSR machine. A rotating magnetic field is imposed, and the d-q axis parameters are estimated simultaneously from the field solution. In addition, such a method allows the cross-saturation to be considered as well. [ABSTRACT FROM PUBLISHER]