Control method based on cascade bidirectional DC-DC converter

Abstract

The invention discloses a control method based on a cascade bidirectional DC-DC converter. The method is relatively simple; and by means of controlling a capacitance voltage through a control unit to be equal to product of a first power voltage and a turns ratio N of a transformer coil, the method can realize soft switching of all switching devices of the cascade bidirectional DC-DC converter in a full-load range. Meanwhile, while transmitting the same power, effective value of resonant inductor current of the cascade bidirectional DC-DC converter can be minimal. Overall efficiency of the cascade bidirectional DC-DC converter is improved.

Description

technical field [0001] The invention relates to a control method based on cascaded bidirectional DC-DC converters. Background technique [0002] In the cascaded bidirectional DC-DC converter, the first-stage DC-DC converter is a bidirectional phase-shifting full bridge. At present, most of the bidirectional phase-shifting full bridge control strategies are basically as follows: [0003] 1. The control strategy of bidirectional phase-shifting full-bridge isolation transformer is that the switching device on one side shifts the phase, and the other side uses the diode rectification of the switching device in parallel. Parallel diodes rectify, diodes have reverse recovery problems, large losses, and cascaded bidirectional DC-DC converters have low efficiency. [0004] 2. Two-way phase-shifting full-bridge isolation transformer. The switching tubes on both sides of the full-bridge isolation transformer phase-shift each other. Although this control method can achieve full-load...

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Problems solved by technology

[0003] 1. The control strategy of bidirectional phase-shifting full-bridge isolation transformer is that the switching device on one side shifts the phase, and the other side uses the diode rectification of the switching device in parallel. Parallel diode rectification, diodes have reverse recovery problems, large losses, and low efficiency of cascaded bidirectional DC-DC converters

[0004] 2. Two-way phase-shifting full-bridge isolation transformer on both sides of the switching tube phase-shifting each other. Although this control method can achieve full-load soft turn-on, it cannot take into account the effective value of the resonant inductor current in the full-load range, and the control method is complicated.

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