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Front. Inform. Technol. Electron. Eng.  2010, Vol. 11 Issue (8): 629-636    DOI: 10.1631/jzus.C0910607
    
Feedback analysis and design of inductive power links driven by Class-E amplifiers with variable coupling coefficients
Tian-liang Yang, Chun-yu Zhao, Da-yue Chen*
Institute of Intelligent Mechatronics Research, School of Electronic, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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Abstract  The efficiency of inductive power links driven by Class-E amplifiers may deteriorate due to variation in the coupling coefficient when the relative position of the radio frequency (RF) coils changes. To solve this problem, a new design methodology of power links is presented in this paper. The aim of the new design is to use the feedback signal, which is a phase difference between the driving signal and the output current of the Class-E amplifier, to adjust the duty cycle and angular frequency of the driving signal to maintain the optimum state of the inductive power link, and to adjust the supply voltage to keep the output power constant when the coupling coefficient of the RF coils changes. The parameter adjustments with respect to the coupling coefficient and the feedback signal are derived from the design equation of the inductive power link. To validate the feedback control rules, a prototype of the inductive power link was constructed, and its performance validated with the coupling coefficient set at 0.2 and a duty cycle of 0.5. The experimental results showed that, by adjusting the duty cycle, the angular frequency, and the supply voltage, the power link can be kept in optimal operation with a constant output power when the coupling coefficient changes from 0.2 to 0.1 to 0.25.

Key wordsInductive power link      Closed-loop Class-E amplifier      High efficient      Variable coupling coefficient     
Received: 12 October 2009      Published: 02 August 2010
CLC:  TN721.2  
Fund:  Project (No. 60271031) supported by the National Natural Science Foundation of China
Cite this article:

Tian-liang Yang, Chun-yu Zhao, Da-yue Chen. Feedback analysis and design of inductive power links driven by Class-E amplifiers with variable coupling coefficients. Front. Inform. Technol. Electron. Eng., 2010, 11(8): 629-636.

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http://www.zjujournals.com/xueshu/fitee/10.1631/jzus.C0910607     OR     http://www.zjujournals.com/xueshu/fitee/Y2010/V11/I8/629


Feedback analysis and design of inductive power links driven by Class-E amplifiers with variable coupling coefficients

The efficiency of inductive power links driven by Class-E amplifiers may deteriorate due to variation in the coupling coefficient when the relative position of the radio frequency (RF) coils changes. To solve this problem, a new design methodology of power links is presented in this paper. The aim of the new design is to use the feedback signal, which is a phase difference between the driving signal and the output current of the Class-E amplifier, to adjust the duty cycle and angular frequency of the driving signal to maintain the optimum state of the inductive power link, and to adjust the supply voltage to keep the output power constant when the coupling coefficient of the RF coils changes. The parameter adjustments with respect to the coupling coefficient and the feedback signal are derived from the design equation of the inductive power link. To validate the feedback control rules, a prototype of the inductive power link was constructed, and its performance validated with the coupling coefficient set at 0.2 and a duty cycle of 0.5. The experimental results showed that, by adjusting the duty cycle, the angular frequency, and the supply voltage, the power link can be kept in optimal operation with a constant output power when the coupling coefficient changes from 0.2 to 0.1 to 0.25.

关键词: Inductive power link,  Closed-loop Class-E amplifier,  High efficient,  Variable coupling coefficient 
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