Transient phase shift control method for dual-active active bridge based on extended phase shift

Abstract

The invention discloses a transient phase shift control method for a dual-active active bridge, and the topological structure of the dual-active active bridge consists of two H bridges and a high-frequency transformer, the duty ratio of all switching tubes is 50%, and the switching tubes of the same bridge arm are in complementary conduction; the control method comprises the steps that the phase difference between the left upper switching tube and the right lower switching tube of the first H bridge is an inner phase shift angle, and the phase difference between the switching tube of the second H bridge and the right lower switching tube of the first H bridge is an outer phase shift angle. In a transient state, when a phase shift angle is adjusted at t0, for example, an outer phase shift angle is changed from an initial state D2 to a final state D2, and an inner phase shift angle is changed from an initial state D1 to a final state D'1; in a half cycle starting from t0, an outer phaseshift angle is changed from an initial state D2 to a transition state D''2, and an inner phase shift angle is changed from an initial state D1 to a transition state D''2; and then the outer phase shift angle is changed into a final state D'2, and the inner phase shift angle is changed into a final state D'2. A half-cycle transition phase shift angle is introduced, so that the current impact of thetransformer is reduced on the basis of not changing the power flow characteristics, and the dynamic response rate is improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, relates to a dual-active active bridge, and in particular relates to a transient phase-shift control method in an extended phase-shift mode. Background technique [0002] High-frequency transformers are widely used in bidirectional isolated dc / dc converters instead of power frequency transformers, which have the advantages of small size and light weight. Dual active active bridge converters have high power density, easy soft switching, strong bidirectional transmission capability, modularity and symmetry advantages, and are widely used in motor drives of electric vehicles, superconducting magnet power systems, microgrid energy storage systems, etc. There are more and more applications in systems requiring bidirectional energy transfer. [0003] The dual active active bridge converter topology is as follows figure 1 shown. It consists of two full bridge H 1 and H 2 , a high frequenc...

AI Technical Summary

Problems solved by technology

Compared with the first two, factor 3 is more serious, which is determined by the phase-shift regulation law of the drive signal of the control circuit, and cannot be improved simply by hardware optimization

[0005] Chinese patent CN 104467434 A proposes a transient phase shift control method, which introduces the phase shift angle of the intermediate link to eliminate the DC bias, but is only applicable to the dual active active bridge in the single phase shift angle operation mode. The mode is extended phase shift, and when two phase shift angles need to be changed at the same time, this method is difficult to work

Chinese patent CN 110912919A monitors the transformer current in real time. If the threshold value is exceeded, the driving signal will cause the primary and secondary switch tubes of the transformer to reverse in advance to suppress the instantaneous current amplitude. The threshold value of this method is difficult to set in real time, and the DC bias can only be appropriately reduced. does not completely eliminate

In the prior art, the solution of transformer series capacitance is adopted, but this will inevitably increase the cost and volume of the circuit

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