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The magnetic-geared double-rotor permanent magnet motor is fused permanent magnet brushless DC motor and field modulated magnetic gear,which is a kind of low speed and high torque direct drive motor. It has opened up a new idea for improving the motor efficiency and torque density. It is an urgent problem to be solved that establish the electromechanical dynamics model and high-performance control of the kind of component. It is intended to establish the electromechanical coupling dynamic analysis model,and grasp the law that is the influence of controller parameters for driving system performance. Starting from the principle of motor operation,the motor can be decomposed into a brushless DC motor that is equivalent to high speed rotor and armature,and a magnetic gear equivalently that to the double rotor assembly considering elastic effect. The two part is combined of high-speed rotor. The numerical model of the motor is built in MATLAB/Simulink,and the system is regulated by using the PID control. Although the simulation results show that although there are the problems of nonlinear and coupling in the system,the tuned PID control can make the system track the input signal and achieve comprehensive performance index well.

The field modulated magnetic gear is a kind of non- contact magnetic drive device,and the Halbach permanent magnet array is a new permanent magnet structure which contains permanent magnets with variable magnetizing directions. In order to recognize the magnetic field property and mechanical property of the field modulated magnetic gear with Halbach permanent magnetic array,the fundamental and harmonic components of the magnetization of the Halbach permanent magnetic array are expressed by Fourier expansion. By using finite element method,two magnetic gears with radial magnetization array and Halbach array are established respectively. The magnetic field and magnetic field harmonic in air gaps of two models are compared,and the torque- angle characteristics and cogging torque characteristics of the inner rotor and outer rotor of each model are studied. By contrast,the magnetic gear with Halbach array has a more smooth torque output than the magnetic gear with radial magnetization.

A novel synchronous permanent magnet planar motor (SPMPM) with iron core is proposed. It has higher continuous force compared to the coreless SPMPM. In the novel SPMPM, two sets of windings for generating x-direction thrust and y-direction thrust are perpendicularly fixed in the x-direction slots and y-direction slots of a mover core, respectively. For control system development applications, an electromagnetic model is derived and the analytical method for calculating the model parameters is also reported. The model describes an important characteristic of the novel SPMPM that the x-direction thrust and y-direction thrust are independent of each other. To verify the model and the parameter calculation method, the finite element method (FEM) is used for calculating the phase inductances and electromagnetic forces of an example SPMPM. The results from FEM are in good agreement with the results from the analytical equations. It demonstrates the feasibility and credibility of the proposed model and parameter calculation method to a certain extent. Index Terms--Coupling, inductance, magnet array, planar motor, winding.

This paper investigates three kinds of permanent-magnet arrays used in planar motors with polarity centers distributed in the lattices of a matrix. The magnetic field of every kind of magnet array is analyzed by analytical methods. First, we give a Laplace equation of magnetic scalar potential and a series of boundary conditions. Then, we derive the analytical expressions of magnet field strength and magnet flux density in the air gap of each kind of magnet array by the method of separation of variables. Finally, we compare the three types of magnet arrays on the basis of the analytical solutions. Index Terms--Analytical solution, magnet array, planar motor, scalar magnetic potential.