一次側控制之無線電能傳輸系統

Abstract

本論文提出一個一次側控制方式之低功率無線電能傳輸系統，在此無線電能傳輸系統一次側與二次側電路之間不需有任何導線連接。此一次側控制方式實施在無線電能傳輸系統中以調節傳輸電能並且二次側端不需要額外的調節電能電路，一個充電保護電路被嵌入於無線電能傳輸系統之二次側端並且監視充電電流與電壓，以保護充電電池受到過大的充電電流或電壓。利用具有零電壓切換功能之LLC諧振式電源轉換器和E類功率放大器，以最小化因為漏電感所造成的電能傳輸耗損。依據實驗結果，二次側的充電電池被灌輸一個穩定的電流在電流模式下，並且當電池電壓接近4.1伏特時，充電電流會降低並轉為電壓模式。實驗結果顯示，在各種的空氣間隙的情況下無線電能傳輸系統都能達成一次側控制，無線電能傳輸系統具LLC諧振式電源轉換器電流模式下整體電能傳輸效率在33.5 % 和 54.1 % 之間，而無線電能傳輸系統具E類功率放大器電流模式下整體電能傳輸效率在30 % 和 66.2 % 之間，二次側充電保護電路的電能轉換為86.5 %，並且當無線電能傳輸系統沒有傳輸電能時，二次側充電保護電路的靜態電流為20μ安培。

This dissertation presents a low power wireless energy transmission system (WETS) with the primary side control method. The WETS has no physical wire connection required between the primary and secondary-side circuits. The primary side control method implemented in the WETS does not require extra space in the secondary side to regulate transmission energy. A charging protection is embedded within the secondary side to monitor the charging current and battery voltage, and to protect the battery against over-charging current or voltage. LLC resonant converter and class-E power amplifier structures with zero voltage switching are utilized to minimize transmission loss due to leakage inductance. According to experimental results, the secondary side battery is fed a stable charging current in current mode and low current in voltage mode where the battery voltage reached approximately 4.1V. The results show that the WETS achieved primary side control in all air-gap conditions. The overall efficiency of the WETS with LLC resonant converter is between 33.5 % and 54.1 %, and that of the class-E amplifier is between 30 % and 66.2 % when operating in the current mode. The efficiency of the secondary-side protection circuit is 86.5 %, and the quiescent current of secondary-side protection circuit is 20μA when the WETS does not work.