DC-DC converter additionally provided with buffer and method for reducing backflow power

Abstract

The invention discloses a DC-DC converter additionally provided with a buffer and a method for reducing the backflow power. Buffer capacitors are respectively connected to IGBT power switching tubes of the DC-DC converter in parallel so as to form a buffer. The flowing direction of power is controlled according to the demand for power of the left side and the right side of the dual-active-bride DC-DC converter, the output power and the backflow power are defined, soft switching conditions under different voltage transformation ratios K are analyzed and compared by adopting a double phase shiftcontrol method, and a transmission power limit and an optimal backflow power control program are calculated and optimized. The backflow power at the right side is used for charging an inductor and the backflow power at the right side is taken as a control target in the control. According to the method, the DC-DC converter deploys a buffer on a power switch, thereby effectively improving the performance of the converter, suppressing the overvoltage peak, reducing EMI (electromagnetic interference), and reducing the loss of the power switching tubes. Compared with the adoption of a single phaseshift method, the adoption of the double phase shift control method has the advantages that the backflow power of the converter is significantly reduced and stabilized, the application prospect is very wide, and popularization is carried out easily.

Description

technical field [0001] The invention relates to a DC-DC conversion electrical appliance, in particular to a dual active bridge circuit DC-DC converter equipped with a buffer, which belongs to the category of power electronics and electric engineering. Background technique [0002] Dual active bridge (dual-active-bridge, DAB) DC-DC converter, that is, DC-DC converter, is functionally equivalent to two unidirectional DC-DC conversions, increasing the bidirectional flow capacity of energy, and Compared with the traditional unidirectional DC-DC converter, the number of components is saved, the volume of the system is reduced, the cost is reduced, and the efficiency of the system is improved at the same time. Therefore, the dual active bridge DC-DC converter has been more and more widely used in green energy such as DC motor drive, uninterruptible power supply, electric vehicle and wind power generation. The existing dual active bridge DC-DC converter, that is, the main circuit ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to propose a DC-DC converter capable of suppressing voltage spikes and reducing electromagnetic interference (EMI) in view of the current situation that the existing dual active bridge DC-DC converter has a relatively large voltage change and the use effect is not good when the input and output voltages do not match. -DC converter and its method for reducing the return power, which greatly reduces the return power of the dual active bridge DC-DC converter, and makes the return power zero within a certain range

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