DAB converter turn-off loss optimization control method and system based on predictive control

Abstract

The invention discloses a DAB converter turn-off loss optimization control method and system based on predictive control. The method comprises the steps of obtaining an input voltage, an output voltage, an output reference voltage and an output current of a dual-active bridge converter; according to the obtained input voltage, output voltage, output reference voltage, output current and a single phase shift prediction controller, obtaining a phase shift amount under single phase shift control; acquiring transmission power according to the phase shift amount under single phase shift control; and according to the transmission power and a turn-off loss optimization calculation model, obtaining an internal phase shift amount and an external phase shift amount under extended phase shift control, wherein the turn-off loss optimization calculation model is obtained according to the following steps: obtaining an expression of turn-off loss according to the relationship between the inductive current of the converter and the turn-off loss of the switching element; performing optimal solution on the turn-off loss expression by taking the turn-off loss minimization under the current transmission power as a target to obtain a turn-off loss optimization calculation model; and controlling each switching element according to the internal phase shift amount and the external phase shift amount.

Description

Technical field [0001] The present invention relates to the field of converter control technology, and more particularly to a DAB converter to turn off the loss optimization control method and system based on predictive control. Background technique [0002] The statement of this section is merely the background technology information related to the present disclosure, which is not necessarily constituted in prior art. [0003] With the development of various new types of distribution systems, the double-active bridge converter (DAB converter) as its key interface has been widely used. Under the low switching frequency, the magnetic element volume in the DAB converter is usually It will be large, which makes the system's power density. Therefore, by increasing the switching frequency to reduce the size of the converter, improve the power density. However, as the switching frequency increases, the system's switching loss will increase significantly. Therefore, the switching loss o...

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Problems solved by technology

[0005] However, the strategy of optimizing the current peak value only considers the optimization of the conduction loss of the converter. Under high-frequency conditions, the switching loss is greatly increased, and the optimization effect of this scheme will be relatively reduced; when zero-voltage conduction is achieved through soft switching technology , the DAB converter is easier to achieve zero-voltage turn-on, thereby greatly reducing the turn-on loss, but zero-current turn-off is difficult to achieve in DAB, making it difficult to achieve turn-off loss through the above soft switching technology

[0006] In addition, when the above method is combined with traditional PI control for converter control, the transient performance of the converter is relatively poor

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