Design and Development of a 1.5kw full Bridge DC-DC Converter

Abstract

This thesis presents full-bridge DC DC converter using power MOSFET, for power rating of 1.5 kW. Switching power supply are more efficient and flexible in use than linear regulator and much less in weight than that of linear regulator since they require less heat sinking for the same output rating. In this topology voltage mode control IC LTC3722-2 is used, which generates four gate pulses to drive the power MOSFET by synchronous dual mode phase modulated full bridge controller. Full duty cycle control can be achieved by this controlling IC. Gate driver IC IR2110 is used to drive the full-bridge configuration. In this topology a ferrite core based high frequency transformer is designed, which also steps down the voltage level and provides isolation. This converter is designed for load current 15 A and output voltage 110 V DC. The switching frequency is 25 kHz and input voltage is 160-280 V AC . In rectifier section ultrafast diode UF5408 are used in bridge rectifier. The targeted efficiency for this switch mode power supply is 90%. For gate drive isolation opto-couplers MCT2E are used. In feedback circuit TL431 sets the voltage level for comparator pin of the control IC which will in turn control the duty cycle. Experimental results showing using variation of full duty cycle at 25 kHz operating frequency are demonstrated in the thesis. The output voltage remains fairly constant for variations in input voltage of the power supply.