Design and control of a permanent magnet rotlin motor for new foldable photovoltaic units

In this study, a new permanent magnet rotary-linear (RotLin) motor is proposed for foldable photovoltaic units. Firstly, the mechanical structure, operation principles and magnetic circuits of the motor are introduced, and a design procedure elaborated the parameters calculation in the linear part and the rotary part. Finite element method (FEM) is used to analyze the magnetic field of the motor, and linear force outputs and torque outputs are obtained. Secondly, a control scheme is designed for the prototype of the motor including the position control and the speed control. The deformation on the mover and the magnetic coupling effect between the linear part and the rotational part are discussed. Finally, experimental results show that this motor can simultaneously realize a linear movement with continuous rotation. The linear poisoning accuracy can achieve 0.4 µm and the angular speed can be controlled with steady errors less than 3 rpm, proving the effectiveness of the proposed RotLin motor.