Start control method of phase-shifted full-bridge converter and phase-shifted full-bridge converter

Abstract

The invention provides a start control method for a phase-shifted full-bridge converter and the phase-shifted full-bridge converter, and the method comprises the steps that waves are transmitted in a first control mode during starting, and the duty ratio of the transmitted waves is the minimum value in the starting process; in the starting process, the duty ratio is gradually increased until the duty ratio is increased to a first preset value, meanwhile, whether the output current is larger than a second preset value or not is judged, if yes, the duty ratio is set to be 50%, and then the first control mode is switched to a second control mode for wave sending; otherwise, the waves are still transmitted in the first control mode; and when the output voltage of the phase-shifted full-bridge converter reaches a target value, starting is ended. Two control modes are adopted for wave transmission, the first control mode is adopted during light-load starting, the second control mode is switched to during heavy-load starting, and heat loss is greatly reduced; and in addition, the two control modes are set to be the same effective duty ratio during switching, the loop coupling problem is avoided, and the switching stability is improved.

Description

technical field [0001] The invention relates to the technical field of vehicle-mounted converters, in particular to a start-up control method of a phase-shifted full-bridge converter and a phase-shifted full-bridge converter. Background technique [0002] The on-board DCDC is responsible for the energy conversion between the on-board high-voltage battery and the low-voltage battery. The phase-shifted full bridge (PSFB) converter has the characteristics of high efficiency, low cost, simple design and electrical isolation. has a wide range of applications. It can be used not only to charge constant voltage loads such as batteries, but also to directly supply power to various constant resistance or constant current loads. [0003] When the DCDC converter is started, since the lagging arm only resonates with the primary side leakage inductance and parasitic capacitance to ensure its soft switching, it is difficult to soft-open the lagging arm at light load and low current, resu...

AI Technical Summary

Problems solved by technology

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a start-up control method of a phase-shifted full-bridge converter and a phase-shifted full-bridge converter, which are used to solve the problem of large loss at light load in the prior art and switch unstable problem

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