Analysis, Modeling, and Verification of Limited Angle Torque Motors with Irregular Slot Numbers for Performance Improvement

This article presents the theoretical analysis, numerical modeling and experimental verification of a novel limited angle torque motor (LATM) with an irregular slot number. Based on the magnetic circuit, analytical equations are derived for predicting the torque-angle characteristic of the LATM, including both the constant torque region and linear region. By these equations, the relationship between the performance and leading parameters is established, providing a reference for the quick design of LATM. The idea of utilizing the linear region to expand the angular operation range of LATM is then proposed. It is shown that by active control of the winding current, the linear region can be reasonably used. Due to larger cogging torque in the integral-slot LATM, an irregular slot number topology is proposed to suppress the cogging torque. The results are validated by finite element analysis, and further verified by experimental measurements on a prototype machine.