DC-DC CONVERTER AS POWER SUPPLY OF BATTERY CHARGER 100 V 300 W USING 25 kHZ SWITCHING FREQUENCY

Dc-dc converter with full-bridge topology is the best option to use as power supply with high power and high voltage level. Full-bridge topology combines the voltage properties of half-bridge topology and the current properties of the push pull topology. It is an elaboration from buck converter topology with isolated transformer as galvanic isolation. The main components of the dc-dc convert full-bridge are inverter, high frequency transformer, high frequency rectifier and filter. The inverter is designed in a full-bridge topology that can transfer power greater than the half-bridge. Switching mode that used in this research is phase-shifted PWM ZVT. This switching mode will reduce the loss of switch. High frequency transformer is used to raise the level of output ac voltage from inverter that has a high frequency, the transformer also has smaller dimensions than a common transformer with the same capacity. Rectification of high frequency output transformer is done by a full-bridge rectifier using fast recovery diode. In this study, dc-dc converters used as a power supply for battery charger that is loaded with bulb lamps with 300 W power needed and also eight pieces of lead-acid batteries 12 V in series. The results showed that the efficiency of the converter dc - dc battery charger designed achieve efficiency about 95% for certain circumstances.