Unsaturated-Inductance-Based Instantaneous Torque Online Estimation of Switched Reluctance Machine with Locally Linearized Energy Conversion Loop

This paper proposes a novel dynamic torque estimation method, which can quickly and accurately obtain the instantaneous torque with an online calculation based on the local linearization of the energy conversion loop on the flux linkage-current plane of the switched reluctance machine. According to the real-time information of the points on the loop, six situations are illustrated and analyzed. For each situation, the output mechanical energy is obtained first by calculating the area of the corresponding segmented regions, and then, the instantaneous torque is obtained by the difference algorithm concerning the output mechanical energy and rotor position. For the entire process, the unsaturated phase inductance of the machine, which can be conveniently measured, is the only information required in advance. To verify the effectiveness of the proposed method, detailed simulations and experiments are performed under different operating conditions.