1 Scope and Purpose

This document serves as an operational manual for the 4 kW PSFB-CDR (Phase shifted Full-Bridge with Current Doubler Rectification) stage, DC-DC converter demonstrator application board, utilizing the dsPIC33C DSP digital signal microcontroller. The PSFB board is a 2700W 800V-12VDC Buck mode DC-DC converter which targets EV applications. In a dual rail operation, it meets the full specification of Pout >4000W, offering redundancy and maximizing light load efficiency.

The DC-DC converter uses a high efficiency, soft-switching PSFB stage at the primary side which reaches partial to full ZVS (Zero Voltage Switching) at nominal load. The secondary side is a current doubler rectification stage which reduces maximum current requirements for the magnetic involved, such as transformer and output inductors. The system automatically switches between Synchronous and Asynchronous rectification under light load operation when the system enters DCM.

This document introduces operating principles, test setup and measurement results for different operating conditions.