DC-DC step-down converters improve the efficiency of battery charging systems.

Abstract

The invention relates to a DC-DC step-down converter device that improves the performance of a battery charging system with the ability to enhance efficiency. This device includes a photovoltaic (PV) module arranged at the input power supply of the DC-DC converter (DC power supply 13) used to convert photovoltaic energy into electrical energy to supply DC power to the DC-DC converter, a DC-DC converter module to perform the step-down function, the DC-DC converter module includes: primary side isolation transformer (20), four step-up power switches (1, 2, 3, 4), a step-up coil (19), and two capacitors (14, 15). The four capacitors (1.2, 2.2, 3.2 and 4.2) are installed in parallel with the four power switches (1, 2, 3, 4) to achieve a 0V voltage switching mode. Secondary side of isolation transformer (20), four rectifier diodes (5, 6,.7, 8), two voltage clamping diodes and parasitic energy release (9, 11), two voltage clamping capacitors (16, 17) and output voltage filter circuit of coil (21) and capacitor (18), central processing unit (CPU) 22 includes processing software to generate PWM (Pulse Width Modulation) control signals for power switches in the step-down module to adjust the on / off time of DC voltage conversion to lower DC voltage, where, when the DC-DC converter is operating, CPU (22) controls PWM pulses for power switches (1, 2, 3, 4) in the step-down module to reduce the output voltage.

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