Optimal duty ratio voltage mismatching control method for current type bidirectional DC-DC converter

Abstract

The invention discloses an optimal duty ratio voltage mismatching control method for a current type bidirectional DC-DC converter, and belongs to the electric power electronic field. The optimal duty ratio voltage mismatching control is adopted; by regulating the duty ratio and the phase shifting angle between a high-voltage side voltage and a low-voltage side voltage, circuit on-state loss and annular current loss caused by current can be lowered, and meanwhile, the current peak value and power device stress are lowered; in addition, by virtue of an optical duty ratio strategy, the duty ratio is limited and the annular current stage time is reduced, and meanwhile, through voltage mismatching control, a transformer voltage is in mismatching, and a higher junction capacitance charging current before switch-on of a high-voltage side switching tube which is the most difficult in realizing soft switching is achieved, so that realization of soft switching is ensured, and circuit loss is further lowered; and by virtue of the optimal duty ratio voltage mismatching control method, the voltage stress and annular current loss can be lowered, low ripple operation of the circuit input current is realized, the voltage withstand level of the device is lowered, the switch-on loss of the device is lowered, the conversion efficiency is improved, the cost is lowered, and full-load-range soft switching is realized.

Description

technical field [0001] The invention relates to a current source type bidirectional DC-DC converter and an optimal duty ratio voltage mismatch control method for the current type bidirectional DC-DC converter, belonging to the direction of high-frequency switching power supply in the field of power electronics. technical background [0002] The current source DAB is suitable for similar occasions because the current ripple on the current source side is small, and the charging and discharging current is relatively mild for the battery. Taking the application of fuel cell vehicles as an example, the application of this type of converter in this application background is introduced below. [0003] A fuel cell is an electrochemical device that can directly convert the chemical energy of fuel into electrical energy without going through an intermediate process, so it can avoid intermediate conversion losses and achieve high power generation efficiency. At the same time, it has t...

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Problems solved by technology

[0007] In order to overcome the above-mentioned converter and control method, there are the following technical problems: (1) high current spike; (2) large circulation loss; (3) high voltage stress, which affects the reliability of the converter; (4) affects the efficiency of the converter ; (5) The required withstand voltage of the device is high and the cost is high

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