SPMSM sensorless control for wide speed range using full-order flux observer

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.