DC-DC converters are used in electric vehicle battery charging applications, offering improved efficiency.

Abstract

The invention relates to a DC-DC step-down converter for electric vehicle battery charging applications with the ability to improve performance. This device includes a DC-DC converter module to perform the step-down function. The DC-DC converter module includes: a primary side isolation transformer (12, 13), four step-up power switches (1, 2, 3, 4), a coil (11), and capacitors (9) supporting voltage division and participating in the switching process. 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.The secondary side of the isolation transformer (12, 13), three rectifier diodes (5, 6, 7) and output voltage filter capacitor (10), the central microprocessor (CPU) 14 includes processing software to generate PWM (Pulse Width Modulation) control signals for the power switches in the step-down module to adjust the on / off time of the DC to DC voltage conversion to a lower DC voltage, where, when the DC-DC converter is operating, the CPU (22) controls the PWM pulse for the power switches (1, 2, 3, 4) in the step-down module to reduce the output voltage.

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