High-efficiency three-phase bidirectional DC-DC converter

Abstract

A high-efficiency three-phase bidirectional DC-DC converter disclosed by the present invention comprises a three-phase bridge-type switching circuit, a resonant cavity, three isolation transformers and a three-phase bridge-type rectification circuit, the resonant cavity comprises three resonant circuits and a selection circuit, and each resonant circuit comprises a first inductor, a second inductor and a first capacitor. One end of the second inductor is connected with one end of the first capacitor and one end of the first inductor, the other end of the second inductor is connected with a primary winding of an isolation transformer, and the other ends of the first capacitor and the first inductor serve as a first connecting end and a second connecting end of a resonance circuit respectively; the first connecting end is connected with the three-phase bridge-type switching circuit and the second connecting end is connected with the isolation transformer in the first state, and the second connecting end is connected with the three-phase bridge-type switching circuit and the first connecting end is connected with the isolation transformer in the second state; dotted terminals of secondary windings of the three isolation transformers are respectively connected with midpoints of three bridge arms of the three-phase bridge rectifier circuit.

Description

technical field [0001] The invention relates to the technical field of power conversion, and more particularly to a high-efficiency three-phase bidirectional DC-DC converter. Background technique [0002] The bidirectional DC-DC converter is a DC / DC converter that can adjust the bidirectional transmission of energy according to the needs. It is mainly used in energy storage systems, vehicle power supply systems, feedback charging and discharging systems, hybrid energy electric vehicles and other occasions. [0003] In the traditional LLC resonant bidirectional converter, the ZVS conduction of the primary side switch tube and the ZCS conduction of the rectifier side diode can be realized regardless of the forward and reverse operation, but when the energy flows in the reverse direction, its circuit characteristics are no longer It is an LLC resonance characteristic and degenerates into an LC resonance characteristic. The maximum voltage gain of LC resonance becomes 1, which g...

AI Technical Summary

Problems solved by technology

[0003] In the traditional LLC resonant bidirectional converter, the ZVS conduction of the switch tube on the primary side and the ZCS conduction of the diode on the rectification side can be realized regardless of forward and reverse operation, but its circuit characteristics are no longer when the energy flows in the reverse direction. It is LLC resonance characteristic and degenerates into LC resonance characteristic. The maximum voltage gain of LC resonance becomes 1, which greatly reduces the voltage gain during reverse operation and greatly narrows the output voltage range, so it is not suitable for working in a wide voltage range. The state of bidirectional flow of energy limits its application scenarios

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