In a collaborative project with Professor Arif Kazi of Aalen University in Germany, a modular brushless DC motor (BLDC motor) with a reluctance based magnetically levitated rotor was developed as a teaching tool for universities. Both types of actuators (BLDC motors which are based on the Lorentz principle and reluctance actuators) are widely used in industrial applications because of their robustness and their low maintenance.
The BLDC motor is designed as an axial field motor with the motor windings placed on a PCB board. Six reluctance actuators which are mounted around the rotor and used under closed loop conditions stabilize the rotor in five degrees of freedom. Beacuse of the simple design, it is possible to build this system using standard manufacturing techniques available in most workshops.
The modular concept allows the use of the system in different levels of teaching. In its basic configuration, the commutation of BLDC motors as well as the design of position controllers by using model based design can be demonstrated. The next step focuses on the teaching of the magnetically levitation of a disc. In this step, the forces of reluctance actuators, couplings between different axes and the control of nonlinear systems can be explained. In the final step, the motor can be run magnetically levitated andin six degrees of freedom controlled.