Design and Development of a Synergetic Controller for a Permanent Magnet Synchronous Motor Drive System

Abstract

Electric vehicles are gaining increasing attention by automotive manufacturers in an attempt to reduce carbon footprint and produce more eco-friendly vehicles. Electric vehicles are powered by electric motor drives instead of the conventional combustion engine. Permanent Magnet Synchronous Motor (PMSM) drives receive most interest in this field for their powerful torque profiles that are suitable for vehicle traction. This study explores a new non-linear controller, the synergetic controller, and evaluates its performance in motor drives applications and particularly for the PMSM. Firstly, the new controller is presented and the controller design is explained. A new macro-variable is proposed to improve the performance of the controller. The effect of each of the controller’s gains is studied separately. Finally, the controller’s performance is compared with the field oriented controller, which is the most robust and reliable control technique in motor drives applications. This work also investigates the regenerative braking phenomenon in PMSM. Regenerative braking is crucial for electric vehicle applications since the mechanical energy of the motor during deceleration or braking periods can be harvested and used to charge the vehicle’s battery or a proper energy storage unit designed for such purpose. Regenerative braking is implemented using two techniques; speed control and torque control. The different algorithms are validated through experiments using a PMSM drive system developed in the Mechatronics (MTR) lab. The experimental results show that the proposed macro-variable improves the performance of the synergetic controller significantly. The synergetic controller is able to overcome non-linearities in the system, such as static friction, faster than the field oriented controller. The system also experiences fewer harmonics under the synergetic controller. Synergetic controller is also more prone to wide signal variations. As for regenerative braking, the speed control mode of operation is suitable for harvesting more energy. On the other hand, the torque control mode generates more power and higher current values flow back to the DC source. Synergetic controller improves the performance of the PMSM drive.