Kyoung-Gu Lee, June-Seok Lee, and Kyo-Beum Lee, "SPMSM Sensorless Control for Wide Speed Range Using Full-Order Flux Observer," in Proc. ICIT Conf., Feb./Mar. 2014, pp. 164–168. > Paper

In this paper, the observer based on the flux estimation method is presented. There are reduced-order and full-order types in flux

observers based on the flux estimation. Reduced-order flux observers have a simple structure and short calculation time. However,

they have drawbacks which comes from noise and disturbance. Therefore, full-order flux observers are used in this paper. 

Conventional full-order flux observers are methods that use an estimated d- and q-axis currents in the flux estimation.

Nevertheless, the gain that includes the speed information of the denominator has a problem of deteriorating performance since 

the magnitude of the gain value largely increases in the low speed range. To control the speed precisely at both low- and high-

speed ranges, the proposed full-order flux observer uses the improved gain. The improved gain has a stable estimation performance

in both low- and high-speed range. This paper verifies the excellence of the proposed algorithm by using the improved full-order ​

flux observer that has stable estimation performance through the simulation.