We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. Fo...We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. For a 2-mm-long and 10-μm-wide laser coated with high-reflectivity on the rear facet, more than 170mW of output power is obtained at 20℃ with a threshold power consumption of 2.4 W, corresponding to 30mW with a threshold power consumption of 3.9 W at 90℃. Robust single-mode emission with a side-mode suppression ratio above 25 dB is continuously tunable by the heat sink temperature or injection current.展开更多
Rotor imbalance is identified as one of the predominant vibration sources in high-speed magnetically suspended motors.Due to factors such as rotor machining accuracy errors and uneven material distribution,synchronous...Rotor imbalance is identified as one of the predominant vibration sources in high-speed magnetically suspended motors.Due to factors such as rotor machining accuracy errors and uneven material distribution,synchronous vibration interference is caused.Moreover,sensor runout generates harmonic currents,which are attributed to material irregularities and inhomogeneity in the roundness of the sensor detection surface.Harmonic currents can generate harmonic vibrational forces that are transmitted to the motor housing,jeopardizing control accuracy and the device's operational lifespan.In order to achieve real-time reduction of harmonic currents at specified frequencies and improve the accuracy of harmonic suppression,this paper proposes an algorithm for variable phase anglefiltering of an adaptive cascaded mode notchfilter.This paper performed dynamic modeling and analysis of the magnetically suspended rotor system with rotor imbalance and verified the correctness of the dynamic model.Subsequently,the structure of an adaptive notchfilter with variable phase angle is introduced,highlighting the capability to maintain stability by adjusting the compensatory phase of the system.By comparing the harmonic current suppression performance of cascaded and parallel mode notchfilters,the cascaded method can better enhance the overall frequency selectivity,emphasizing its ability to adjust the compensation phase based on the phase angle of the input signal at different frequencies to maintain system stability.Simulation and experimental results show that harmonic currents can be successfully suppressed in the cascade mode,and the amplitude of the synchronous frequency current is reduced by 94.4%.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2013CB632801the National Key Research and Development Program under Grant No 2016YFB0402303+2 种基金the National Natural Science Foundation of China under Grant Nos61435014,61627822,61574136 and 61306058the Key Projects of Chinese Academy of Sciences under Grant No ZDRW-XH-2016-4the Beijing Natural Science Foundation under Grant No 4162060
文摘We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. For a 2-mm-long and 10-μm-wide laser coated with high-reflectivity on the rear facet, more than 170mW of output power is obtained at 20℃ with a threshold power consumption of 2.4 W, corresponding to 30mW with a threshold power consumption of 3.9 W at 90℃. Robust single-mode emission with a side-mode suppression ratio above 25 dB is continuously tunable by the heat sink temperature or injection current.
基金supported by the National Natural Science Foundation of China under Grant 32371868.
文摘Rotor imbalance is identified as one of the predominant vibration sources in high-speed magnetically suspended motors.Due to factors such as rotor machining accuracy errors and uneven material distribution,synchronous vibration interference is caused.Moreover,sensor runout generates harmonic currents,which are attributed to material irregularities and inhomogeneity in the roundness of the sensor detection surface.Harmonic currents can generate harmonic vibrational forces that are transmitted to the motor housing,jeopardizing control accuracy and the device's operational lifespan.In order to achieve real-time reduction of harmonic currents at specified frequencies and improve the accuracy of harmonic suppression,this paper proposes an algorithm for variable phase anglefiltering of an adaptive cascaded mode notchfilter.This paper performed dynamic modeling and analysis of the magnetically suspended rotor system with rotor imbalance and verified the correctness of the dynamic model.Subsequently,the structure of an adaptive notchfilter with variable phase angle is introduced,highlighting the capability to maintain stability by adjusting the compensatory phase of the system.By comparing the harmonic current suppression performance of cascaded and parallel mode notchfilters,the cascaded method can better enhance the overall frequency selectivity,emphasizing its ability to adjust the compensation phase based on the phase angle of the input signal at different frequencies to maintain system stability.Simulation and experimental results show that harmonic currents can be successfully suppressed in the cascade mode,and the amplitude of the synchronous frequency current is reduced by 94.4%.
