Buck-mode constant power control method and circuit of soft switching bidirectional direct-current converter

Abstract

The invention relates to a buck-mode constant power control method and control circuit for a soft switching bidirectional direct-current converter. The soft switching bidirectional direct-current (DC)converter comprises a first input bridge arm, a second input bridge arm, a first output bridge arm and a second output bridge arm. The control method comprises the following steps: when the soft switching bidirectional DC converter is in a buck mode, adjusting the duty ratio of the first output bridge arm according to the difference between the output power of the first output bridge arm and preset power; and when the duty ratio of the first output bridge arm reaches a first preset threshold value, adjusting the duty ratio of a preset phase shift angle, wherein the preset phase shift angle isthe phase shift angle when the trigger pulse of the first input bridge arm is ahead of the trigger pulse of the first output bridge arm. According to the invention, the soft switching bidirectional DC converter can be controlled with the optimal efficiency, and the stability and reliability of the system during operation are improved.

Description

technical field [0001] The invention relates to the technical field of electrical automation, in particular to a method and circuit for controlling constant power in a step-down mode of a soft-switching bidirectional DC converter. Background technique [0002] With the increasing energy crisis, there is an increasing demand for DC power supplies with higher efficiency, higher power density, and wide input and output ranges. In low-current and high-frequency applications, the turn-on and turn-off losses of the switching tube constitute the vast majority of the circuit loss. Reducing this part of the loss is of great significance for further increasing the switching frequency and power density. [0003] In the traditional converter control method, the switching tube is hard-turned-on, and the voltage and current are not zero during the turn-on process, which will cause electromagnetic interference and turn-on loss, and is not suitable for high-frequency, high-efficiency, and h...

AI Technical Summary

Problems solved by technology

[0004] At present, there is a soft-switching modulation strategy for the four-switch buck-boost converter in the existing technology, but no specific control method for the control system based on efficiency optimization is given.

Images