Control and dynamics of constant power loss based operation of permanent magnet synchronous motor drive system

The operational envelope of electrical machines is limited by the maximum permissible power losses of the machine. The control and dynamics of the permanent magnet synchronous motor (PMSM) drive operating with constant power losses is proposed in this study. The proposed operational strategy is modeled and analyzed. Its comparison to other control strategies that limit current and power, demonstrates the superiority of the proposed scheme. The implementation of the proposed scheme is developed. It is achieved with an outer power loss feedback control loop. This has the advantage of retrofitting the present PMSM drives with the least amount of software/hardware effort. The PMSM drives in this case then can use the existing controllers to implement the control criteria such as constant torque angle, unity power factor, constant air gap flux linkages, maximum torque per unit current or maximum efficiency operation. Experimental verification of the control strategy is provided.