A full-range soft-switching control method for dual active bridge dc/dc converters based on frequency regulation

Abstract

The invention discloses a full-range soft-switching control method for dual active bridge DC / DC converters based on frequency regulation, which adds switching frequency regulation on the basis of traditional double-phase-shift control to expand the soft-switching working range of the converter , so that the converter can realize zero-voltage turn-on in the full load range, which reduces the switching loss of the converter, thereby improving the efficiency of the dual active bridge converter. The invention does not need to change the conventional dual active bridge circuit structure, does not add sensors, and saves costs; in addition, the invention also increases the control freedom of the dual active bridge circuit, making the control more flexible, and can be applied to the direction of high-frequency isolation switching power supply .

Description

technical field [0001] The invention belongs to the technical field of DC / DC converter control, and in particular relates to a full-range soft switching control method of a dual active bridge DC / DC converter based on frequency regulation. Background technique [0002] The dual active bridge DC-DC converter can realize electrical isolation and bidirectional flow of energy, and has the characteristics of high efficiency, low cost, and high power density. Its circuit structure is as follows: figure 1 shown. In recent years, with the development of technologies such as electric vehicles, uninterruptible power supplies, and new energy power generation, dual active bridge converters have been more and more widely used. [0003] Traditional dual active bridge circuits usually adopt a single-phase-shift control (Single-Phase-shift, SPS) method, which is simple to control, easy to realize soft switching, and has high transmission efficiency. However, this method has the problem of ...

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Problems solved by technology

However, this method has the problem of reactive energy backflow. When the input and output voltages do not match, the energy backflow is serious, and it is difficult to achieve soft switching, which increases the loss of the converter.

[0004] Chinese patent (CN201410117100) proposes a series-parallel dual active bridge circuit. The invention overcomes the fact that the dual active bridge circuit cannot be used in occasions where the voltage becomes relatively large through the series-parallel form, and reduces the voltage and current of the switch tube. Stress, improve the efficiency of the converter, however, the switching sequence involved in the invention is the traditional single phase shift control, which cannot achieve soft switching when the voltage and load vary in a wide range

However, due to the existence of the junction capacitance of the switching device, the critical continuous current cannot release the energy stored in the junction capacitance in the dead time, and the voltage stress of the switching tube is high during the switching process, which will also cause switching losses, especially when the voltage is relatively low. Switching losses due to voltage stress are particularly noticeable in applications with high

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