本論文擬研製一應用於感應加熱之數位控制電源系統，其系統架構分為前級的降壓轉換器和後級的全橋換流器。透過降壓轉換器降低輸出功率，系統於剛啟動時先進行一次諧振頻率掃描，尋找40 kHz ~ 60 kHz 中諧振頻率的絕對極大值。全橋換流器使用擾動觀察法來實現感應加熱所需之最大功率追蹤，藉由小幅度擾動之前鎖定的諧振頻率來維持其相對極大值，確保最大化感應加熱產生之實際輸出功率。而諧振電容與加熱負載形成一等效R-L-C並聯諧振電路，當電路發生諧振時，會有最大功率轉移效果，使負載加熱達到目的。本文首先介紹感應加熱之基本理論，接著對研究之電路的動作模式及控制方法進行分析，並設計電路功率元件之參數。最後實作出一輸入電壓 300 Vdc、輸出功率6 kW及切換頻率40 kHz ~ 60 kHz之雛型電路，並由實驗結果驗證本文之理論分析。

The main purpose of this thesis is to propose a digital control power system used for induction heating. The system is separated into two stages-the former, a buck converter and the latter, a full-bridge inverter. The output power is limited through the buck converter while the system begins a one-time scan between 40 kHz ~ 60kHz searching for the absolute maximum resonant frequency in this interval. Perturbation and Observation method is applied to the full-bridge inverter to realize Maximum Power Point Tracking. The actual output power generated by induction heating is maximized by slightly adjusting the resonant frequency found before to maintain its local maximum. When the parallel R-L-C resonant circuit formed by the resonant capacitor and load begins to resonate, maximum power is transferred to the load, causing it to begin to heat. In this thesis, the basic theory of induction heating is introduced initially. Then, the operating principles and control methods of the circuit are discussed, and the design procedure is also described. Finally, a prototype of the system with input voltage 300 Vdc, output power 6 kW and switching frequency between 40 kHz ~ 60 kHz is implemented to verify the theoretical analysis.

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