Symmetrical half-bridge LLC resonant bidirectional DC-DC converter

Abstract

The invention discloses a symmetrical half-bridge LLC resonant bidirectional DC-DC converter, which belongs to the technical field of power electronic application. Topological structures on the two sides of the converter are symmetrical, and adopted components adopt a complex function design. When a switching network and a resonant network on one side of a high frequency transformer function, the switching network and the resonant network on the other side are automatically evolved into a rectifier-load network, and the networks on the two sides commonly form the whole LLC resonant converter to realize power conversion in a corresponding direction. Because the structures are completely symmetrical, reverse conversion can be possible; and in the reverse conversion, the topological structures can be automatically reconstructed to form a reverse LLC resonant converter to realize reverse power conversion. The symmetrical half-bridge LLC resonant bidirectional DC-DC converter achieves effective improvements in conversion efficiency, power density, dynamic performance and electromagnetic compatibility, reduces the electrical stress of components at work, has a reduced volume and a reduced weight, and realizes highly-efficient, isolated and bidirectional DC/DC power conversion.

Description

technical field [0001] The invention belongs to the technical field of power electronics applications, and in particular relates to a symmetrical half-bridge LLC resonant bidirectional DC-DC converter. Background technique [0002] A bidirectional DC-DC converter refers to a DC-DC converter that can change the direction of energy transmission as needed while maintaining the polarity of the DC voltage on both sides of the converter. Compared with the scheme of using two sets of unidirectional DC-DC converters to achieve bidirectional energy transmission, the bidirectional DC-DC converter uses the same converter to achieve bidirectional energy transmission, and the overall number of devices used is less, which can be more quickly The switching of power conversion in two directions has the advantages of high efficiency, small size, good dynamic performance, and low cost. In the face of rapid changes in the global environment, energy shortages, and rising pressure on energy con...

AI Technical Summary

Problems solved by technology

Similar to the unidirectional zero-voltage switching PWM bridge DC-DC converter, the energy stored in the energy storage inductor or the leakage inductance of the isolated high-frequency transformer is used to realize the zero-voltage switching of the bridge arm. The disadvantage is that the converter has a large internal Circulating energy affects the improvement of the energy conversion efficiency of the converter, especially when the converter is light-loaded, it is difficult to achieve soft switching

The application of resonance eliminates the overlapping phenomenon of voltage and current during the switching process of the switching device in the converter, and reduces the switching loss of the switching device. However, the converter needs to work with frequency conversion, so that the filter of the converter and the closed-loop controller It is difficult to optimize the design. In addition, there are defects such as large voltage and current stress in the converter.

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