A Study of Piezoelectric Transformers and Resonance Circuit Design Aided with Wireless Power Transfer Capability

  • 李 宗勳

Student thesis: Doctoral Thesis


With a progress of technology the merits of wireless energy transfer system is increasingly applied and witnessed in power transmission and energy conversion devices In the mean time the concept of plasma discharging through the firing of high-voltage source for cleaning and sterilization is widely adopted in industries and families Therefore this dissertation is aimed to investigate the application of wireless power transfer for high-voltage power converter applications where the frequency-tracking control the feedback mechanism the resonant topology and the design process are also included The thesis starts with the improvement of wireless power delivers in which the inductive coil magnetic coupling and distance change that affecting the transmission efficiency are both analyzed This is followed by the investigation of the resonance compensation structure and parameters by which the feedback mechanism of phase-loop locked strategy is implemented to achieve the frequency-tracking of the system Next considering that the inductive coil design plays a critical role in the wireless power transfer the dissertation proposes a manufacturing process and design approach where the suitable values of coil for the applications under different source power transmission gaps and coupling coefficients can be calculated with ease To verify the feasibility of this system theoretical analyses are made and mathematical models are formulated along with hardware realizations Test results indicate that the proposed method can adjust the operating frequency to promote the power transmission efficiency while the output voltage can be well stabilized The coil design and resonance circuits suggested in this dissertation also ensure that the expected amount of power can be transferred in a wireless way and the soft-switching is fulfilled These outcomes are served as useful references for wireless power transfer applications Subsequently in consideration of the plasma-driven circuit often employs the bulky magnetic inductors and capacitors as resonant elements to induce the high voltage these complex circuit designs along with feedback device would affect the operating performance restricting the industry competition for a further circuit development Hence this dissertation proposes a power converter with PT-based resonant architectures to replace conventional inductor-capacitor resonant tanks The modular capacity operation made in this study helps increase the output power along with a higher flexibility Experimental results indicate that the output voltage can be effectively increased to achieve the goal of plasma discharging while the dimension of driving circuit is reduced and the resonant circuit design is simplified Next in order to widely extend the application fields of wireless power transfer system for high-voltage power converters this dissertation proposes a prototype design of contactless charging system platform The dissertation includes an operating frequency correction method and a compensator design of converters such that sufficient amount of power can be supplied and the output voltage can be maintained for plasma-driven circuits In addition the circuit has added a battery module to reach the requirement of a portable plasma generator Conclusively from all of control strategies and system architectures proposed in this dissertation the overall circuit system is seen to possess the merits of electrical isolation and electrode insulation while the design process can be largely simplified The research results gained from this dissertation can be also served as the reference of industrial design and development for plasma-driven systems Keywords: wireless power transfer frequency-tracking inductive coil design plasma-driven circuit piezoelectric transformer resonant circuit feedback mechanism
Date of Award2015 Feb 3
Original languageEnglish
SupervisorShyh-Jier Huang (Supervisor)

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