| Summary: | 碩士 === 國立雲林科技大學 === 電機工程系 === 104 === A new high step-up dc-dc converter is proposed in this thesis. This new high step-up converter utilizes the input voltage, clamped-capacitor, and the secondary side of the coupled-inductor to charge the switched-capacitor and the secondary side of the coupled inductor also charges two multiplier capacitors in parallel during the turn-on interval of the switch. The input voltage, coupled-inductor, and multiplier capacitors are in series connection to the output to accomplish the purpose of high voltage gain during the turn-off interval of the switch. By adjusting the turns ratio of the coupled inductors, the proposed circuit does not need to be operated at high duty cycle to achieve the high voltage gain. The voltage stress of the switch and diodes can be decreased to cut down the cost. Moreover, the energy of the leakage inductance can be recovered to reduce the voltage spike of the switch. Therefore, the switch with lower conduction resistance can be applied to reduce the conduction loss and increase the efficiency.
Finally, simulation and experiments are conducted. A prototype circuit with input voltage of 24 V, output voltage of 400 V, and output power of 200 W is implemented to validate the property of the proposed converter.
The other new high step-up interleaved converter is also proposed in this thesis. This new high step-up converter utilizes the interleaved boost converter to be in series connection with the voltage doubler module. The secondary side of the coupled inductors are in interleaved series connection and shared by two voltage doubler modules to accomplish the interleaved energy storage. Then, the input voltage, coupled-inductors, and multiplier capacitors are in series connection to the output to achieve the purpose of high voltage gain. The proposed circuit can be operated at lower duty cycle to achieve high voltage gain by adjusting the turns ratio of the coupled inductors. The proposed circuit has less elements and the voltage stress of the switches and diodes can be decreased to reduce the cost. The conduction loss can be reduced and the efficiency can be increased when the switch with lower conduction resistance is applied.
Finally, a prototype circuit of a 400 W high step-up converter with input voltage of 24 V and output voltage of 400 V is realized. Through simulation and experiments, the validity and property of the proposed converter can be verified .
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