Design and Development of 1.5 KW Full-Bridge DC-DC Converter with Novel Feedback Configuration and Improved Performance

Abstract

SMPS is preferred over linear regulated power supplies mainly because of its smaller size. Also lower weight, higher e ciency and lower cost are its advantages. The project work includes designing of MOSFET based high frequency AC-DC switched mode power supply (SMPS) for frequency of 50 kHz which is used for maintaining constant load side DC voltage. At the input side, uncontrolled recti er bridge is designed to obtain DC voltage link for the converter. The speci cations of SMPS being 1.5 kW, 110 V and 15 A, full-bridge DC-DC converter (inverter) is designed for controlling the ow of energy. For purpose of isolation, high frequency transformer is designed and used at the output side of the inverter. For obtaining voltage mode control (VMC) of SMPS, ICs SG3525 and LTC3722-2 are studied, analyzed and implemented. Also circuit is designed for providing variable dead band externally to the control pulses of inverter. The output of control IC is fed to the inverter through proper driver for purpose of isolation as well as obtaining proper pulses to driver the inverter. Various driver ICs like IR2113, IR2110, TC4429, M57962CL and discrete drivers of di erent Totem pole con gurations are studied, con gured and tested for its operation and nally proper driver card is designed with the driver IC IR2110. The main purpose of providing the closed-loop to any power supply is for obtaining better voltage regulation. Here the closed-loop control is provided by using proper VMC methodology. For this system, closed-loop control has been designed by using voltage regulator IC LT1431, output of which is given to optocoupler 4N35, for purpose of isolation. The output of optocoupler is then given to the non-inverting bu er LM324 before giving it to the compare pin of the control IC for purpose of reducing loading on control IC. With this design satisfactory voltage regulation is obtained. Improvement in performance parameters of SMPS like reduction of voltage spikes coming at switching frequency of inverter, improvement in input side power factor and reduction in THD has to be obtained with linear as well as non-linear loads.