Triple-phase-shift control method of dual-active-bridge converter

Abstract

The invention relates to a control method of a dual-active-bridge converter, and aims to provide a triple-phase-shift control method of the dual-active-bridge converter. According to the triple-phase-shift control method, an output voltage controller used for adjusting an output voltage is arranged in the dual-active-bridge DC converter of a bi-directional topological structure, an input signal ofthe output voltage controller is a difference value between a given value of a secondary side DC voltage and an actual measured value, and an output signal of the same is a control signal alpha whichis used for adjusting a duty ratio D1 of a primary side bridge arm neutral-point voltage, a duty ratio D2 of a secondary side bridge arm neutral-point voltage and a phase difference D3 of the voltages. The triple-phase-shift control method solves the problems of dual-active-bridge current stress optimal solution and control complexity, obtains the corresponding D1, D2 and D3 when the inductive current stress is minimum under each power point, solves relationships among the D1, D2, and D3, proposes the simple control method, and can realize the effect that the converter operates according to atrajectory with the minimum current stress by using just one PI controller.

Description

technical field [0001] The invention relates to a control method of a single-phase or multi-phase double active bridge converter, which belongs to the direction of a bidirectional direct current isolation switching power supply in the field of power electronics. Background technique [0002] Converters with isolation and bidirectional energy flow have a wide range of application requirements, such as microgrids, solid-state transformers, electric vehicle charging piles, etc. Whether it is an AC or DC bidirectional converter, its core part is a medium and high frequency isolated bidirectional DC-DC converter. In practical applications, in order to reduce energy loss, cost and volume, efficiency and power density are important indicators for evaluating isolated bidirectional DC-DC converters. [0003] Among many isolated bidirectional DC-DC converter topologies, dual active bridge has been widely studied and applied because of its symmetrical structure, flexible control, and ...

AI Technical Summary

Problems solved by technology

In the article "Current-stress-optimized switching strategy of isolated bidirectional DC–DC converter with dual-phase-shift control" published in IEEE Transaction on Industrial Electronics [Journal of Power Electronics] in 2013, it is proposed to simultaneously adjust the D 1 、D 2 and φ to reduce the current stress, but since D1 and D2 are kept equal, this control method essentially only adjusts two dimensions, and the minimum value of the current stress obtained is only a local optimum; in 2012, IEEE Transaction "Closed form solution for minimum conduction lossmodulation of DAB converters" published on Power Electronics【Journal of Power Electronics】by changing D 1 ,D 2 and φ three-dimensional decoupling adjustment to reduce the conduction loss, but the expression of this method is complicated, and no closed-loop design is performed at the middle power level, and the complicated control method makes it unsuitable for engineering practice

"Unified Triple-Phase-Shift Control to Minimize Current Stress and Achieve Full Soft-Switching of Isolated Bidirectional DC–DC Converter" published in IEEE Transaction on Industrial Electronics [Journal of Power Electronics] in 2016 proposed the use of Karush–Kuhn–Tucker The conditional method, by freely adjusting the three dimensions, obtains the minimum value of the current stress at each power point, but this method adjusts D 1 、D 2 When it is necessary to know the output power and Df, it is necessary to add a current sensor to perform real-time sampling of the output current, and it is difficult to accurately collect high-frequency current, which increases the cost of the controller and the difficulty of control

[0005] In summary, the existing dual active bridge control methods cannot take into account the optimal solution of current stress and the control complexity

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