Study on the optimized control strategy of the DAB converter

Abstract

Due to the rapid development of DC power generation and transmission technology, it has become the central link of high voltage AC transmission and low voltage DC distribution network, and the medium and low voltage DC distribution network has attracted more attention. In the medium and low voltage DC distribution network, the high-frequency isolation bidirectional DCDC-driven converter is required as an interconnection equipment for electrical isolation, current conversion and bidirectional power flow. To reduce the voltage stress of the switching element of the dual active bridge (DAB) autoconverter used in the medium voltage environment, the three-level topology is incorporated into the autoconverter of the audio broadcast. The three-input-output level (3L) DAB converter has the advantages of both input-output level automatic converter and DAB converter, which is more convenient to operate and has great application and development prospects. For the 3L-DAB converter and its optimal management, taking the double-free-phase-shift controller as an example, it first constructs the segmented time-domain map mode of the automatic converter, and analyzes its operation characteristics, which provides a basis for the subsequent research. The power switching transistors of the two-channel free phase-shift timing converter meet the soft switching requirements, and we deduce the influence of the nonlinear influence on the soft switching range. Then, the reliability optimization strategy is given in view of the non-matching conditions, and then the equivalent conditions of the two optimization methods are derived. Finally, we analyze that the segmented time domain mapping method is not suitable for the model changes, construct the multi-degree of freedom universal phase shift controller mode, and derive the fundamental wave optimization game.