Design and fabrication of contactless optical thermometer with rapid and accurate performance has become a research hotspot in recent years. Herein, CaSc2O4: Yb3+/Er3+ is employed as the intermediary for temperature sensing under the excitation of 980 nm, which is proven to afford an ultra‐sensitive and high‐resolution optical thermometry in multiple ways based on the fluorescence intensity ratio (FIR) technology. The optimal thermal sensing behaviors are realized by the FIR of Er3+:2H11/2 → 4I15/2 to 4S3/2 → 4I15/2 transition, which has a relative sensitivity of 1184/T2 and a minimal resolution of 0.03 K along with a maximal absolute error of 0.96 K. Besides that, the FIR between the thermally coupled Stark sublevels of Er3+:4F9/2 manifold (FIRR) as well as that of Er3+: 4I13/2 manifold (FIRN) can also provide excellent optical thermometry. The relative sensitivity of FIRR‐based and FIRN‐based optical thermometers are calculated to be 402/T2 and 366/T2, respectively, with a same minimal resolution of 0.09 K, which possess the potential to be used for biomedicine due to the inherent advantage of their operating wavelengths located in the biological window. The results demonstrate that CaSc2O4: Yb3+/Er3+ is a promising candidate for temperature sensing with multipath, high sensitivity, and superior resolution.
The control of a high performance alternative current (AC) motor drive under sensorless operation needs the accurate estimation of rotor position. In this paper, one method of accurately estimating rotor position by using both motor complex number model based position estimation and position estimation error suppression proportion integral (PI) controller is proposed for the sensorless control of the surface permanent magnet synchronous motor (SPMSM). In order to guarantee the accuracy of rotor position estimation in the flux-weakening region, one scheme of identifying the permanent magnet flux of SPMSM by extended Kalman filter (EKF) is also proposed, which formed the effective combination method to realize the sensorless control of SPMSM with high accuracy. The simulation results demonstrated the validity and feasibility of the proposed position/speed estimation system.
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