Design of Digital Control System for DCDC Converter of On-Board Charger

Abstract EN

Vehicle charging power supply is widely used because of its small size and portability.

Aiming at the problems of slow dynamic response, subharmonic, oscillation and limited soft-switching range of phase-shifted full-bridge DC/DC converter, the paper proposed a modified PSFB converter by introducing clamp diodes at the primary side of the transformer to suppress voltage oscillation of the transformer’s secondary side.

Also, digital peak current phase-shifting control and slope compensation are introduced to avoid subharmonic oscillation.

Dynamic dead-time control technology introduced adjust the dead-time in different load ranges through the dead-time adjustment subroutine.

Finally, an experimental platform of on-board charging phase-shifted full-bridge DC/DC converter is established.

The experimental results show that the power supply eliminates subharmonic oscillation, achieves a wide range of soft-switching, improves the dynamic performance and antiinterference ability of the system, and optimizes the power efficiency.