A bidirectional resonant DC converter and its control method

Abstract

The invention discloses a bidirectional resonant DC converter and a control method thereof. The bidirectional resonant converter consists of a low-voltage side power supply, a high-voltage side power supply, first to fourth switching tubes on the low-voltage side, first to fourth switching tubes on the high-voltage side, The first and second resonant inductors, resonant capacitors, first and second capacitors, and a transformer are composed; when the energy is transmitted from the low-voltage side to the high-voltage side, the bidirectional resonant DC converter realizes power through the phase-shift control of the switching tubes on both sides control; when the energy is transmitted from the high-voltage side to the low-voltage side, the bidirectional resonant DC converter realizes power control through the frequency conversion control of the switching tube; the bidirectional resonant DC converter of the present invention can not only realize the bidirectional transmission and control of energy on both sides, but also It can realize soft switching of all switching devices in the full load range, and is especially suitable for high-frequency, high-efficiency, high-power-density bidirectional power conversion applications.

Description

technical field [0001] The invention relates to a bidirectional resonant DC converter and a control method thereof, belonging to the technical field of power electronic converters, in particular to the technical field of bidirectional isolated DC-DC power conversion. Background technique [0002] Bidirectional DC converters can realize power transmission and control in two directions, and have the functions of two unidirectional DC converters. It has broad application prospects in power systems including energy storage links such as renewable energy power generation, electric vehicles, aerospace power supply, and smart grids. [0003] In various energy storage systems, the voltage of the energy storage battery is usually very low, while the voltage on the other side (such as the DC bus side) is usually high. How to achieve high-efficiency bidirectional power conversion in the case of a large voltage difference between the two sides is Important issues of domestic and foreig...

AI Technical Summary

Problems solved by technology

However, existing resonant DC converters are usually only suitable for unidirectional power transfer applications, and it is difficult to achieve bidirectional power transfer

Taking the bidirectional LLC resonant converter as an example, since its resonant cavity can only be placed on one side of the circuit, when the energy is transmitted from the side of the resonant cavity to the side that does not contain the resonant cavity, the working principle and process of the circuit are the same as those of the unidirectional The LLC resonant converter is the same and can achieve high-efficiency energy transfer; however, when the energy is transferred from the side that does not contain the resonant cavity to the side that contains the resonant cavity, the circuit structure will behave as a traditional series resonant converter. At this time, the circuit It can only work with step-down and there is a large turn-off loss and circulation loss, and the circuit performance will be greatly affected

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