| Summary: | 碩士 === 國立臺北科技大學 === 電力電子產業研發碩士專班 === 104 === The main theme of this thesis is to design and implement an half-bridge resonant converter controlled by digital signal processor. The output voltage is controlled by the output signal of DSP. The resonant inductor, resonant capacitor and magnetizing inductor are used to achieve zero voltage switching and reduce switching loss. In addition, synchronous rectifier control of LLC converter is used to reduce conduction loss in secondary side.
Besides, the circuit parameter is designed with the large magnetizing inductance to reduce primary side current. However, the output voltage regulation and zero voltage switching may not be achieved under light load condition. A hybrid control strategy is proposed using the pulse width modulation and auxiliary detection circuit to determine the zero voltage switching and regulate output voltage under light load condition. The proposed PWM control method have two degrees of freedom to achieve ZVS by varying the pulse width and lowing the switching frequency rather than changing the deadtime as shown by conventional method.
The signal processor, TMS320F28035, is used as the control platform for the verification of design and implementation. The design specifications include: input voltage 400V, output voltage 12V, total power rating 360W, switching frequency from 77kHz~140kHz, and the maximum efficiency can go up to 94%.
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