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This paper proposes a method to shorten the length of transient response time-stepping finite element analysis (TSFEA) of the dual three-phase permanent magnet synchronous machine (PMSM). Firstly, the initial magnetic potential and stator winding current under steady-state operation conditions in the TSFEA are estimated using time-harmonic finite element analysis (THFEA). Then the achieved relevant values extracted from the real and imaginary part in the time-harmonic solver are injected into a proposed zero-state govern equation called the “zero-state initial solver”, which gives the closer-fitting of initial permeabilities, magnetic potential, and stator winding current in the time domain. Finally, the upper achieved values are transferred into the TSFEA as the initial condition for the following computation. With the well-precalculated solution, the required AC cycles of the steady-state can be effectively reduced, while the computing time of the central processing unit (CPU) is also substantially decreased. The effectiveness and accuracy of the proposed method are verified by comparing it with the conventional methods in a TSFEA of an 6-kW dual three-phase PMSM.

In-wheel direct-drive is the most efficient driving mode for electric vehicles, and it is the trend for applications in the future. In this paper, a novel variable-flux outer-rotor permanent magnet synchronous motor with a hybrid magnetic structure design is developed. Due to the hybrid magnetic pole with Nd-Fe-B and Al-Ni-Co permanent magnet(PM), the air-gap flux can be adjusted by changing the magnetization states of Al-Ni-Co PM, which is beneficial to realize a wide range of speeds and loads from the electromagnetic structure design. Firstly, basic structure features of the motor and the flux-adjusting principle are introduced. The design and calculation method of the PM dimensions is derived based on magnetic circuit analysis. Then the Preisach hysteresis model of Al-Ni-Co PM is described and is adopted to analyze the motor performance with the coupling of the time step finite element method(FEM), and the magnetization are investigated. Finally, the operational performance of the proposed motor is obtained by simulation, which verifies the design.

This paper introduces a Permanent Magnet (PM) synchronous torque motor with an external rotor. Firstly, the basic structural features of this motor are described. Novel spiral magnetic poles and axial-cooling structure is designed to increase the energy density and make the motor compact. The width, thickness and spiral angle of the poles are determined by magnetic computing, in order to ensure the wave of gap magnetic density is sine. To provide an effect cooling structure, the motor side hoods are designed as centrifugal fans to cool the coil down. Multiple air channels are cut in the stator core to increase the ventilation of air. The spiral poles can also constitute spiral air channels and produces wind to cool the magnets. It is possible to choose high electromagnetic load to gain high energy density based on a good cooling effect. Next, the method is determined and the program is compiled for electromagnetic computing. The finite element analysis on magnetic field is conducted by applying ANSYS. Finally, according to the optimization of the structure, a 3 kW prototype is fabricated. The no-load and load experiments are carried out to proof the performance of the motor.