Torque decomposition and control in an iron core linear permanent magnet motor

This paper concerns the decomposition and control of the torque produced by an iron core linear permanent magnet motor. The proposed method is based on the dq0-decomposition of the three-phase currents using Park´s transformation. The torque is decomposed into a reluctance component and two electromagnetic components which depend on the d- and q-axis currents. By curve fitting a harmonic model on finite-element results and measurements, the torque components are modeled as a function of the motor position. To control the torque at any position, the required d- and q-axis currents are solved from the torque model. It is shown that the proposed controller successfully controls the torque in both FE-simulations and during measurements.