Direct-current magnetic bias suppression method and device for dual-active-bridge direct-current converter

Abstract

The invention discloses a direct-current magnetic bias suppression method and device for a dual-active-bridge direct-current converter. The method comprises steps of transmitting an input voltage to aband-pass filter for filtering through employing the impact on an input voltage ripple from a direct-current bias in the dual-active-bridge direct-current converter, and inputting a filtering voltageto two independent voltage integration circuits, wherein the integral period is a half period. And the integral voltage of each half period being inputted into the sample hold circuit, the sampled integral voltage being inputted into the control regulator by subtracting the integral voltage, an error signal of the duty ratio being outputted and superposed with a driving signal of the original duty ratio, the final duty ratio being obtained, and the driving signal being outputted. In practice, a voltage source is not an ideal voltage source and is generally composed of a converter, and therefore ripples of a preceding-stage power supply can be superimposed on input voltage ripples. The band-pass filter is adopted to filter the input voltage, direct current bias can be suppressed only by considering the switching frequency of the dual-active-bridge direct current converter, and practicability and reliability of the system are improved.

Description

technical field [0001] The invention belongs to the technical field of DC converter control, and in particular relates to a DC bias suppression method and device for a dual active bridge DC converter. Background technique [0002] Dual Active Bridge DC converter (Dual Active Bridge, DAB) is widely used in distributed power generation, new energy electric vehicles, uninterruptible power supply And other high-power occasions are widely used. However, due to the incomplete symmetry of the parasitic parameters of the circuit hardware and the delay of the driving signal, the DC bias of the high-frequency transformer occurs. The DC bias will lead to an increase in the peak value of the inductor current, an increase in switching loss and stress, and even an excessive DC bias will cause saturation of the magnetic components, a spike in the current, and an increase in temperature, which will eventually cause the circuit to burn out. [0003] At present, the traditional method of el...

AI Technical Summary

Problems solved by technology

Connecting DC blocking capacitors in series will bring greater power loss and service life problems. The active control method of sampling current has relatively high requirements on the sampling accuracy and bandwidth of the current sampling module.

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