Transient state phase-shifting control method for double-drive full-bridge DC/DC converter

Abstract

The invention discloses a transient state phase-shifting control method for a double-drive full-bridge DC / DC converter and belongs to the field of power and electronic technologies. The method includes the steps that at a steady state period, an AC output side of a first full-bridge of the double-drive full-bridge DC / DC converter is adjusted to be a square wave vh1 with the duty ratio being 50%, and a phase position is fixed; an AC output side of a second full-bridge of the double-drive full-bridge DC / DC converter is also adjusted to be a square wave vh2 with the duty ratio being 50%, equal phase-shifting angles are arranged between the rising edges of the square wave vh1 and the square wave vh2 and between the falling edges of the square wave vh1 and the square wave vh2 respectively; at a transient state time period, the phase-shifting angles are changed from phase-shifting angles D1 of a first switching period T1 to phase-shifting angles D2 of a second switching period T2, in the second switching period T2, the phase-shifting angle between the rising edge (or the falling edge) of the square wave vh2 and the falling edge (or the rising edge) of the square wave vh1 is adjusted to be a phase-shifting angle D20, and the phase-shifting angle between the falling edge (or the rising edge) of the square wave vh2 and the rising edge (or the falling edge) of the square wave vh1 is the phase-shifting angle D20. The transient state phase-shifting control method for the full-bridge DC / DC converter can reduce current shock and accelerate dynamic response.

Description

Technical field [0001] The invention belongs to the technical field of power electronics, and relates to a dual-active full-bridge DC converter, in particular to a transient phase shift control method for the dual-active full-bridge DC converter. Background technique [0002] The dual active full-bridge DC converter is a DC converter that can operate in two quadrants. Its topological structure is like figure 1 As shown, the converter mainly consists of two full-bridge converters H 1 And H 2 , Two DC filter capacitors C 1 And C 2 , A high-frequency inductor L and a high-frequency isolation transformer T composition. Since it is functionally equivalent to two unidirectional DC converters, it can greatly reduce the size, weight and cost of the system. It is widely used in DC motor drives, uninterruptible power supplies and electric vehicles that require bidirectional energy flow. [0003] At present, the research directions of dual active full-bridge DC converters at home and abroad ...

AI Technical Summary

Problems solved by technology

In the steady-state process, the dual-active full-bridge DC converter can meet the above premise, but in the transient process, it cannot strictly meet this premise

Especially when the phase shift angle changes, the voltage across the transformer is asymmetrical between two switching cycles, which in turn causes the volt-second product of the voltage across the transformer to be non-zero, which also leads to the occurrence of DC bias

[0004] In order to suppress the DC bias, some literature adopts the scheme of connecting capacitors in series in the transformer, but the rated current of the dual-active full-bridge DC converter will flow through the capacitors, the temperature will rise significantly, and it will also bring large power loss, reducing the efficiency

And in high-power applications, capacitors also increase the size and cost of the converter

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