| The implanted artificial organ, which can imitate one or more functions of hu-man's organ, can reduce adverse effect on the patients' normal life if the functions of their natural organs decline or lose, even can save the patient's life. Those implanted artificial organs always require electric energy to maintain the normal operations. The implanted artificial organ can be powered by implanted battery, however, the output power is small and the service life is not long enough due to its limited store of electric energy. The implanted devices may be powered by transcutaneous energy transmission system (TETS), which transfers the electric energy through the skin to the implanted device, the transmitted power can be infinite, and the output power can be very large yet the service life will be approximate to infinitely long. Since the transmitting power is a little large,TETS requires high efficiency to reduce the possibility of tissue damage caused by overheat as well as constant output voltage to keep the normal operation of the implanted artificial organ. However, the variations of the inductive coils and the equivalent load resistance will change the operation state of TETS, and then the transmission efficiency will deteriorate and the output voltage will also be changed.According to the TETS design equations driven by a Class-E amplifier, which are obtained from the frequency domain analysis of a Class-E amplifier and theoretical analysis of the power transfer,this dissertation presents a feedback technique, which keeps TETS tuning by adjusting the duty ratio and frequency of the driving signal and maintains the output voltage invariable by adjusting the supply voltage when the coupling coefficient of the inductive coil and the equivalent load resistance of the secondary load device vary. According to the feedback technique, a modular design methodology for TETS is presented in this dissertation.The analytical design equations of Class-E amplifier is indispensable in the theo-retical analysis of TETS driven by a Class-E amplifier. The traditional design equa-tions of Class-E amplifier is so complicated that it is difficult to analyze the closed-loop Class-E amplifier.In this dissertation, we analyze the Class-E electrical waveforms of the switch voltage, input current, output current and so on, which satisfy the ZVS (zero-voltage switching) and ZDS (zero-derivative switching) conditions, and then ob-tain the expressions of the parameters. Those expressions will be transformed into the frequency domain, and the design equations of the Class-E amplifier can be obtained by comparing the load impedance of the Class-E amplifier's load branch in frequency domain. The design equations are as functions of the duty ratio and frequency of the driving signal, so it is convenient to analyze the closed-loop Class-E amplifier. Ac-cording to the Class-E amplifier design equations, A feedback technique that keeps the Class-E amplifier tuning with constant output power by adjusting the duty ratio, frequency and supply voltage was presented. The Class-E amplifier design equations and the feedback technique were validated by simulations and experiments.According to the coupling of the inductive coils, the TETS design was pre-sented,i.e. the reflected impedance of the secondary circuit is equal to the equivalent impedance of the class-E amplifier load branch. Combing with the design equations of Class-E amplifier, the TETS design equations with a reflected resistance were obtained. Based on the TETS design equations, the conduct power loss of each component with respect to duty ratio, supply voltage and output power was determined, and then the methodology of improving the efficiency by increasing the duty ratio and supply voltage was presented. Since TETS is sensitive to frequency, the modulation mode of signal transmission that sends information from the outside to the inside or reverse can only use the amplitude modulation (AM). When the signal is send from the outside to inside,the supply voltage adjusting, frequency adjusting and duty ratio adjusting can be employed to modulate the signal to amplitude of the carrier wave;the impedance adjusting can be employed when the signal is sent from the inside to outside.In order to analyze the closed-loop TETS, the variations of the reflected impedance of the secondary and the equivalent load impedance of the Class-E amplifier were obtained when coupling coefficient of the inductive coils, equivalent load resistance of the secondary circuit or both of them change, and then the feedback techniques that keep TETS operate in the optimum state by adjusting the duty ratio and frequency of the driving signal, and maintain the output voltage of the secondary circuit constant by adjusting the supply voltage were presented. According to the feedback control rules, the feedback circuit was designed and its stability was analyzed. The control rules were validated in simulations and experiments According to the feedback circuits, the modular design of closed-loop TETS was presented. The outside circuit contains a microprocessor unit, a power management unit, a supply voltage control unit, a Class-E amplifier unit, a Class-E control unit and a send and receive messages units; the inside circuit includes a microprocessor unit, a power management unit, a power receive unit, a power transfer unit and two send and receive messages unit,In different applications, the closed-loop TETS can be designed by changing some component values in those units according to the design parameters of output power, supply voltage, frequency,duty ratio and so on.In this dissertation. a closed-loop TETS with the capability of sending and receiving message was designed following the modular design methodology, and the experiment results show that the closed loop TETS is a adaptive system and is capable of keeping high transmitting efficiency and maintain the output voltage of the secondary circuit constant as the coupling coefficient and the equivalent load change.
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