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Identification of the stator d -axis and q -axis inductances is essential for the interior permanent magnet synchronous motor (IPMSM) sensorless control system. The signal injection method is an effective way to identify the inductance parameters; however, it requires the rotor position to ensure the accuracy of the injection reference position. To overcome the dependence on the rotor position, a sequence-pulse voltage signal injection method is presented. The matrix least-squares fitting algorithm is utilized to fit the current responses for the inductance identification. Based on the fitting method, the discrete standard orthogonal polynomial with look-up table is introduced to reduce the computation complexity. To reduce the disturbance of the injected signal to the rotor position during the identification process, a double-direction injection position trajectory planning is presented. In addition, the saturation effect on the identification method is also analyzed. The proposed method is verified via a 3.0 kW IPMSM motor drive platform. The identification results are compared with those measured by a standard method and experiment results show that the proposed method can identify the inductance parameters with acceptable accuracy without obtaining the rotor position information.

In this paper, a double-stator linear-rotary permanent magnet motor (DSLRPMM) for linear and/or rotary movement is presented. Since the two types of permanent magnets are orthogonally arrayed on the inner and outer surfaces of the mover core, respectively, the influences of the orthogonal magnetic field (OMF) on the motor electromagnetic characteristics cannot be ignored. Based on the 3-D finite-element method (FEM), the OMF in the motor and the iron core magnetization characteristics are investigated, and a test device is constructed to verify the results obtained by the theoretical analysis and 3-D finite-element analysis (FEA). On the basis of the measured data, the 2-D FEM is employed to analyze the electromagnetic characteristics of the DSLRPMM, including flux density, flux linkage, back-electromotive force, detent force, and cogging torque. The results are compared with that obtained by the 3-D FEA, and they are in agreement. Moreover, a prototype is built and tested. The experimental results verify the correctness of the predictions.

A double stator linear-rotary permanent magnet motor, which has a long tuber ferromagnetic mover core with permanent magnets (PMs) arranged on its inner and outer surfaces, is proposed for two degree of freedom drive in this study. Due to the topology of the long tuber mover, the end-effects, including the interaction between the outer stator end and the mover, the effects of the inner PM length, and the interaction between the inner stator end and the mover, are presented and analysed. Based on the three-dimensional (3D) finite-element method, the influences of the end-effects on the electromagnetic characteristics, such as the flux distributions, flux density, electromagnetic force and torque, and output power, are investigated. Meanwhile, the topology with the minimised end-effects is given, and a prototype is built. The dynamic performances of the prototype are tested via a specific experimental platform. The results are in agreement with that of the 3D finite-element analysis.

In the conventional stator resistance measurement method, the introduction of the dead-time results in the distortion of the output voltage, which will affect the accuracy of the identification results. This paper presents an offline stator resistance identification method, which can avoid the influence of the dead-time effect during the resistance identification process. Firstly, a short pulse voltage signal is injected into the d-axis reference position to generate the d-axis current. Then the zero voltage vector is used to turn on the low-side MOSFETs to release energy stored in the inductor by the stator resistor. By measuring the current response, the stator resistance can be identified. Experiments at different exciting currents are carried out and the experimental results show that the proposed method can overcome the dead-time effect and achieve nice identification accuracy and numerical stability at different exciting currents.

This paper investigates a double stator linear rotary permanent magnet motor (DSLRPMM) with orthogonally arrayed PMs. The DSLRPMM, which involves linear and/or rotary movements, is constituted of two stators and a hollow mover. The aim of this paper is to study the electromagnetic features and optimize the design parameters of the motor using a 3-D finite-element method (FEM). The topology and the operating principle are described, and the original design is given. The influences of the main designed parameters on the electromagnetic torque, force, and total losses are also analyzed. The optimal parameters are given and a prototype is built and tested. The experimental results are in agreement with that of the 3-D FEM analysis.

In this paper, a double-stator permanent-magnet motor that involves linear and/or rotary movements is investigated. The double-stator linear-rotary permanent-magnet motor (DSLRPMM) is constituted of two stators and a hollow mover with permanent magnets affixed on its surfaces. This paper focuses on the main electric and magnetic features of the DSLRPMM. First, the structure and operating principles of the motor are described, and the original design of the motor is also given. Then, the electromagnetic characteristics, including fluxes, torques, forces, etc., are studied owing to the three-dimensional finite-element method analyses. Results are given and compared with the measurements.

An outer-rotor permanent magnet (PM) synchronous machine (OR-PMSM) with amorphous stator core (OR-PMSMASC) is proposed in this paper, which exhibits higher efficiency than conventional silicon steel PM machines. On the basis of the electromagnetic characteristics of the amorphous alloy material (AAM), the general design of the proposed machine is studied, including the structure parameters and the stator-slot/rotor-pole combination. The combination principle of permanent magnets and winding turns for OR-PMSMASC is investigated. Based on the 2-D finite element analysis (FEA), the electromagnetic performances of the proposed machine are analyzed and compared with an OR-PMSM with silicon steel stator (OR-PMSMSSS). A prototype of the OR-PMSMASC is manufactured and tested to validate the FEA results.

Axial field flux-switching permanent magnet machine (AFFSPMM) has significant advantages, such as the short axial size and high torque density. It is suitable for the direct drive in-wheel applications for the electric and hybrid electric vehicles. For improving the reliability, a novel fault-tolerant structure is applied in the AFFSPMM. The stator is composed of E-shaped laminated segments. The phase windings are physically isolated to each other by the middle teeth of E-shaped cores. The field windings wounded around the middle teeth are used to regulate air-gap flux in the proposed machine. The electromagnetic performances are investigated and analyzed by three-dimensional finite element method (FEM), including the inductance, the back-EMF, and the torque capability, etc. It is shown that the fault tolerance is improved in the novel AFFSPMM, and a wide speed range of operation can be attained by a small DC field current.

A three-phase 12/10-pole axial field flux-switching permanent magnet machine (AFFSPMM) with three different stator structures, including parallel permanent magnet and parallel slot (PPPS), parallel tooth and parallel slot (PTPS), and parallel permanent magnet and parallel tooth (PPPT), is analyzed. Based on a 3-D finite element (FE) method, the static characteristics, such as the flux density, PM flux linkage, back-EMF, cogging torque, and electromagnetic torque for the three stator structures are investigated. The influence of the design parameters on the electromagnetic torque is analyzed. The AFFSPMM with PPPS topology has the larger torque, lower cogging torque, and more sinusoidal back-EMF. The prototype with PPPS structure is built and tested. The experimental results are in agreement with the 3-D FE analysis.

In this paper, a double stator linear rotary permanent magnet motor (DSLRPMM) which has a long tuber ferromagnetic mover core with permanent magnets (PMs) arranged on inner and outer surfaces is presented. Based on 3D finite element method (FEM), the end effects caused by the finite length of the inner and outer stators are investigated. The relationships between the end effects and motor parameters, such as outer stator end length, geometric topology, and linear position, are analyzed, and the optimal parameters are given. Meanwhile, the influences of the end effects on the performance characteristics, including airgap flux density, back EMF, output power, force, and torque, of the motor are also studied. Finally, a prototype with optimal topology and parameters is built and tested. The experimental results are in agreement with that of the 3D FEM analysis.

A dual-rotor axial field flux-switching permanent magnet (DRAFFSPM) machine is proposed. A 3-phase 12/10-pole DRAFFSPM machine is designed. The topology and operation principle of the machine are described in detail. The power equation is deduced and the dimensions of the DRAFFSPM machine are determined. The electromagnetic characteristics including the air-gap field distribution, the PM flux-linkage, the back-EMF, and the cogging torque, are investigated based on the 3-D finite element (FE) analysis. The influences of the rotor pole width and the stator slot chamfer on the back-EMF and cogging torque are investigated. It shows that the sinusoidal back-EMF can be gained and the cogging torque can be greatly reduced.

As the complexity of modern industrial drive systems, the two degree of freedom (2-DOF) operation is needed in the many industry drive applications [1]. Linear rotary permanent magnet (LRPM) motor with the simple structure, high power/mass ratio and good dynamic performance has been presented for 2-DOF motion in recent years [2]-[4]. A novel double stator linear and rotary permanent magnet (DSPLRPM) motor is proposed in this paper. The equivalent magnetic circuit model (EMCM) of the motor is established, and the magnetic field is analyzed. The results are confirmed by that of 3D finite element analysis (FEA).

A novel Hybrid Axial Field Flux-Switching Permanent Magnet (HAFFSPM) machine is proposed in this paper. Based on 3-D finite element method (FEM) and Design of Experiment (DOE) method, the influence of the rotor design parameters, such as the rotor pole number, rotor pole width, rotor pole shape and rotor thickness, on the back-EMF and cogging torque is investigated with an invariable stator structure. Both the THD of the back-EMF and cogging torque ripple can be greatly reduced by the optimization of rotor structure, and this makes the machine operate at high efficiency and low noise. The THD is 2.82% and the cogging torque ripple is 0.77 N ·m when the rotor pole width and shape angle are optimized to 12°and 10°, in a 6/11 stator/rotor pole machine, respectively.