Kyoung-Gu Lee, June-Seok Lee, and Kyo-Beum Lee, "Wide-Range Sensorless Control for SPMSM Using an Improved Full-Order Flux Observer," Journal of Power Electronics, vol. 15, no. 3, pp. 721–729, May 2015. -SCIE > Paper

A sensorless control method was recently investigated in the robot and automation industry. This method can solve problems related

to the rise of manufacturing costs and system volume. In a vector control method, the rotor position estimated in the sensorless

control method is generally used. This study is based on a conventional full-order flux observer. The proposed full-order flux observer

estimates both currents and fluxes. Estimated d- and q-axis currents and fluxes are used to estimate the rotor position. In selecting

the gains, the proposed full-order flux observer substitutes gain k for the speed information in the denominator of the gain for fast

convergence. Therefore, accurate speed control in a low-speed region can be obtained because gains do not influence the estimation

of the rotor position. The stability of the proposed full-order flux observer is confirmed through a root-locus method, and the validity

of the proposed observer is experimentally verified using a surface permanent-magnet synchronous motor.