本研究研製一高頻諧振無線充電器，充電器之輸出平均電流為8.5 A，對一7.5 Ah之鋰離子電池充電，為一1.13 C充電之電路。本研究所使用之電路架構為全橋LLC串聯諧振轉換器，操作頻率為350 kHz，並利用全橋相移控制以穩定輸出電流。功率開關元件之操作頻率略高於諧振頻率點，利用諧振之特性使開關達到軟切換，降低切換損失並提高轉換效率。控制上採用數位控制，提高電路之自由度及可靠度，並藉由微控制器之硬體及軟體來保護電路，系統發生異常時可以即時關閉電路運作，達到保護電路之效果。
回授電路則利用峰值回授的方式，於非接觸式變壓器之一次側進行電壓、電流回授。電流回授值與欲控制之輸出電流做比較，將充電電流控制在8.5 A；電壓回授則希望可藉由峰值回授偵測電池電壓，但因與實際負載有所差異，造成峰值回授電壓無法完全反映電池當前電壓，因此將回授電壓整流取平均值後，此平均電壓可透過變壓器匝數比反映出電池當前電壓，故本研究提出未來可利用平均值回授之方式偵測電池電壓，避免電池過充之狀況發生。
本研究主要貢獻為:(1)實現一直流輸入155 V，輸出電流8.5 A，切換頻率350 kHz之無線充電電路，(2)利用諧振電路之特性達到零電壓切換，提高轉換效率，(3)僅從一次側電路做回授，減輕二次側電路之體積及重量，(4)採用數位控制提高系統可靠度。

This thesis studies and develops a high frequency resonant wireless charger. The average output current of the charger is 8.5 A. For a 7.5 Ah lithium ion battery, it is a 1.13 C charging circuit. The proposed system configuration is a full-bridge LLC series resonant converter with an operating frequency 350 kHz. A phase-shift control is to stabilize the output current. The switching frequency is a little bit higher than the resonant frequency, to achieve soft switching and reduce switching loss, increasing the efficiency. In the aspect of control, we use digital control to increase degree of freedom in circuit operation and reliability, and use a microcontroller RX62T for software protection and hardware protection. When abnormal during operation, the system controller can shut down system operation and protect the circuits.
A peak-value feedback circuit to feedback the voltage and current on the primary side of the non-contact transformer is proposed to control and stabilize the charging current to 8.5 A. As for voltage feedback, a peak-value feedback circuit is needed to detect battery voltage, but due to the difference between feedback value and the actual one, peak-value feedback can not completely reflect battery voltage. After rectifying the feedback voltage and taking average, the average voltage can reflect battery voltage. In this case, this research proposes an approach to detect battery voltage by using average voltage feedback.
The main contributions of the proposed research are: (1) implementing a charging circuit with 155 V DC input, 8.5 A current output and 350 kHz switching frequency; (2) using resonant circuit characteristics to achieve ZVS and increasing efficiency; (3) only feedback from the primary side of the transformer, reducing the volume and weight of the secondary-side circuit and (4) using digital control to increase system reliability.

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