A control method based on cascaded bidirectional dc-dc converter

Abstract

The invention discloses a control method based on a cascaded bidirectional DC-DC converter, which is relatively simple. The control unit controls the capacitor voltage to be equal to the product of the first power supply voltage and the transformer coil turn ratio N, and can realize cascaded bidirectional DC-DC All switching devices of the converter switch softly in the full load range. At the same time, when the same power is transmitted, the effective value of the resonant inductor current can reach the minimum. The overall efficiency of the cascaded 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 s...

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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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