Phase shift control method for double-active full bridge bidirectional DC-DC converter in full load range ZVS

Abstract

The invention discloses a phase shift control method for a double-active full bridge bidirectional DC-DC converter in a full load range ZVS and belongs to the high frequency switching power supply inthe power electronic field. The method is characterized in that an excitation current is introduced by the converter on the basis of the original topology, the minimum current required for resonance of a secondary side switch tube when it is turned off is compensated, and thereby the soft switching range of the secondary side switch tube of the converter is expanded. In an EPS mode, based on the injected excitation current, the control strategy for the full load range ZVS and the low current stress is designed, by controlling an on-bridge duty cycle of a high voltage side and an inter-bridge phase shift angle of two full bridges, the converter can operate in the ZVS region at different voltage ratios under different transmission powers, that the converter achieves soft switching over the full load range is guaranteed, switching loss of the switch tube is reduced, moreover, the current peak is reduced, the current stress of the power device is reduced, on-state loss and loop loss of theconverter are reduced, and circuit loss is further reduced. The converter is advantaged in that efficiency and reliability can be improved.

Description

technical field [0001] The invention relates to a phase-shift control method of ZVS in the full load range of a dual-active full-bridge bidirectional DC-DC converter, which belongs to the direction of high-frequency switching power supply in the field of power electronics. Background technique [0002] For power electronics applications that require two-way transmission of power, such as new energy power generation and energy storage batteries, there is a wide range of input and output voltages and load changes. For dual active full bridge bidirectional DC-DC converters, high transmission efficiency is a very important requirement. Zero-voltage switching (ZVS) of power devices can improve converter efficiency. For realizing zero-voltage soft switching, traditional phase-shift control is a very popular and simple control method. But there are some problems that need to be overcome. First of all, the current stress and return power of traditional phase-shift control are rel...

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Problems solved by technology

[0005] In order to overcome the problems that the dual active full bridge bidirectional DC-DC converter cannot realize soft switching in the full load range and the control strategy is complex when considering the junction capacitance, the full load of the dual active full bridge bidirectional DC-DC converter disclosed in the present invention The technical problem to be solved by the range ZVS phase-shift control method is: reduce the turn-on loss and transformer loss caused by current stress and return power, realize the full load range ZVS of the converter in a wide voltage range, and reduce the converter in any working condition. Lower the switching loss of the switching tube, improve the efficiency and reliability of the converter

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