An analytical model for stator yokeless radial flux dual rotor permanent magnet synchronous machine

Abstract

Purpose The purpose of this study is to propose an analytical model with consideration of the permeability of soft-magnetic materials, which can predict the magnetic field distribution more accurately and facilitate the initial design and parameter optimization of the machine. Design/methodology/approach This paper proposes an analytical model of stator yokeless radial flux dual rotor permanent magnet synchronous machine (SYRFDR-PMSM) with the consideration of magnetic saturation of soft-magnetic material. The analytical model of SYRFDR-PMSM is divided into seven regions along the radial direction according to the different excitation source and magnetic medium, and the iron permeability in each region is considered based on the Maxwell–Fourier method and Cauchy’s product theorem. The magnetic vector potential of each region is obtained by the Laplace’s or Poisson’s equation, and the magnetic field solution is determined using the boundary conditions of adjacent regions. Findings The inner and outer air-gap flux density, flux linkage, output torque, etc., of SYRFDR-PMSM are predicted by analytical model, resulting in good agreement with that of finite element model. Additionally, the SYRFDR-PMSM prototype is manufactured and the correctness of analytical model is further verified by experiments on no-load back electromotive force and current–torque curve. Reasonable design of the slot opening width and pole arc coefficient can improve the average output torque and reduce output torque ripple. Research limitations/implications The analytical model proposed in this paper assumes that the permeability of soft-magnetic material is a fixed value. However, the actual iron’s permeability varies nonlinearly; thus, the prediction results of the analytical model will have some deviations from the actual machine. Originality/value The main contribution of this paper is to propose an accurate magnetic field analytical model of SYRFDR-PMSM. It takes into account the permeability of soft-magnetic material and slot opening, which can quickly and accurately predict the electromagnetic performance of SYRFDR-PMSM. It can provide assistance for the initial design and optimization of SYRFDR-PMSM.

Bounded UDE-based Robust Control for MIMO Systems with Application to Vector Control of a PMSM Drive

“…In order to achieve the torque control of the surface-mounted PMSM, the i d = 0 control method is applied, where the the q−axis current reference is set as i qset = 2 3pψ f . The reference model for the current reference is adopted to smooth the current reference, which is designed as idref = − a md i dref + a md i dset (34) iqref = − a mq i qref + a mq i qset (35) and the proposed design of the bounded UDE-based robust control (10), (12), and (13) are applied for vector control of the PMSM drive under the voltage constraint (31). The control parameters are shown in Table II.…”

“…The double-rotor PMSM is illustrated in Fig. 3, where both the double-rotor PMSM and the load motor are controlled by two motor controllers [35]. In the vector control of the PMSM, the electrical model of the PMSM in the d − q rotational synchronous reference frame is given as [30], [36]…”

Optimization design of a new hybrid magnetic circuit motor

“…Yang C.X. proposed an axial-radial flux type permanent magnet synchronous motor [7]. The motor adds an axial excitation part to both sides and a conductive end cover to close the axial magnetic circuit.…”