Maximum torque per ampere control of PMSM based on port-controlled hamiltonian theory

Permanent magnet synchronous motor (PMSM) is viewed as a two-port energy-transformation device. Based on energy-shaping method and port-controlled Hamiltonian (PCH) theory, the modeling and speed control of PMSM is presented. First of all, from an energy-balancing point of view, a nonlinear mathematical model of PMSM is established. Then, the control problem can be recast as finding a controller and an interconnection pattern such that the overall energy function takes the desired form. Using the energy-shaping method of interconnection and damping assignment, the feedback stabilization theory of PMSM system is given. According to maximum torque per ampere (MTPA) control rule, the desired equilibrium of the system is obtained. Feedback stabilization controller is designed and the equilibrium stability is analyzed when the load torque is known. Finally, the methods of load torque estimation and controller design are developed when the load torque is unknown. The simulation results show that the proposed scheme has a good performance and practical use prospects.