Battery charger for a photovoltaic power source

Design procedure of a dc-dc step down converter is presented by means of computer simulations. An input voltage from the photovoltaic module is fed into the converter and regulated to a 13.65 volt voltage source. A feedback controller is introduced to meet the design specifications of 60° phase margin at 8kHz unit gain frequency. The closed loop response is shaped by a double zero compensated OP-AMP circuit. Considerations associate with parameter tolerances of circuit components are included in the design work. The results reveal that a 25 percent more safety factor needs to be added to repair 20% capacitance tolerance.