Dynamic modeling of permanent magnet synchronous machines using direct-coupled time stepping finite element method

A dynamic model of permanent magnet synchronous machines using the finite element method is presented. The system equations, which are based directly on the coupled finite element equations of the magnetic field, the stator circuit equations and the torque equation, are solved by using time stepping method. The major feature in the study is that the classic concept of the d-axis synchronous reactance X_d and q-axis synchronous reactance X_d is not necessary. The merits of the method are that the stator currents and the load angle can be directly computed without any iteration; the effect of the saturation of materials, the eddy-current, the rotor movement and the nonsinusoidal quantities can also be directly included in the system equations as well. The method has been used to study the steady-state and dynamic operation of a 2.5 kW permanent magnet synchronous motor. The performance of the motor with a laminated rotor core and a solid core are compared and discussed in this paper