A small-signal modeling method for dual active full-bridge converters under dual phase-shift modulation

Abstract

The invention discloses a dual-active full-bridge converter small signal modeling method under dual phase shift modulation, linearization is performed on an established large signal equivalent circuit, and a small signal model is established in combination with a mathematical model so that control-output small signal models corresponding to different control variables under different working modesof a converter can be obtained. The invention further discloses a method for further simplifying the model according to the characteristics of the equivalent circuit, and further discloses a circuitmodel for equivalently controlling the output characteristics of the dual-active full-bridge converter by using a first-order system. According to the method, the equivalent circuit is linearized, themathematical model is combined to discuss small signal characteristics of the equivalent circuit, and control-output small signal models of different control variables can be obtained. A first-ordersystem can be used for approximation, and the control-output characteristics of the dual-active full-bridge converter can be approximately described by the first-order system. Therefore, a new thoughtis provided for related research work such as control and stability analysis of the dual-active full-bridge converter.

Description

technical field [0001] The present invention relates to a small signal modeling method of a dual active full bridge (DAB) DC / DC converter, in particular to a small signal modeling method of a dual active full bridge DC / DC converter under dual phase shift modulation . Background technique [0002] Dual active bridge-isolated bidirectional dc / dcconverter (DAB-IBDC) can not only meet the various requirements of DC distribution network for solid-state transformers, but also realize voltage matching, electrical isolation and Active management of power to complete high-efficiency, high-reliability power conversion. At the same time, the converter has attracted wide attention due to its advantages of easy implementation of soft switching, simple and flexible control, and high power density. [0003] In order to analyze the dynamic characteristics of the converter and help design its closed-loop controller, the converter is usually modeled using a discrete iterative model. Howeve...

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Problems solved by technology

Then for the DAB converter, the number of iterations required for the discrete iterative model is large and the model is complex, which brings difficulties to direct application

[0004] In the numerical analysis of the discrete iterative model of the converter, for more multi-degree-of-freedom modulation of sub-states, the model becomes more complex and the physical meaning is not clear enough

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