The Method of Suppressing Transient DC Bias of Three-Port Isolated DC/DC Converter

Abstract

The invention discloses a method for suppressing the transient DC bias of a three-port isolated DC / DC converter, first analyzing the formation mechanism of the TAB transient DC bias under traditional phase-shift control, and determining the formation of the TAB transient DC bias Reason; based on the formation reason, establish its DC bias suppression mathematical model; determine the driving signal combination method that satisfies the DC bias suppression mathematical model, and suppress the transient DC bias. To establish the mathematical model of DC bias suppression, first determine the equivalent circuit of TAB when the voltage of each port acts alone according to the Y-type equivalent circuit of TAB, and then obtain the current expression of each port of TAB by the superposition theorem, assuming that the unit switching period when the phase shift angle changes The volt-second product of the positive and negative amplitudes of the square wave voltages at ports 2 and 3 is zero, and the inductance can still achieve volt-second balance. The current relationship before and after the phase shift angle is obtained, and then the TAB DC bias suppression mathematical model is obtained. . The problem that the transient DC bias affects the safe operation of TAB is solved.

Description

technical field [0001] The invention belongs to the control field of a three-port isolated DC / DC converter, and relates to a method for suppressing a transient DC bias of a three-port isolated DC / DC converter. Background technique [0002] Vigorously developing distributed photovoltaic power generation is an important measure to promote the development and utilization of renewable energy in my country and promote the adjustment of energy structure. The three-port isolated DC / DC converter (triple active bridge, TAB) composed of "PV array + battery + bus load" can realize power transmission and conversion between each two ports, compared with dual active bridge DC conversion For dual active bridge (DAB), the control flexibility is higher and the power supply reliability is better. Among them, the application of high-frequency transformers can not only achieve complete isolation and voltage matching between ports, but also greatly reduce the volume and weight of the device, an...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for suppressing the transient DC bias of a three-port isolated DC / DC converter, to solve the problem of the transient adjustment process of the three-port isolated DC / DC converter under traditional phase-shift control due to shifting The phase angle changes, the DC bias current is generated on the inductance of each port of the converter and the transformer core, which affects the safe operation of TAB and its key components, and the existing TAB DC bias suppression method for modal analysis needs to add additional Hardware facilities and can not solve the problem of DC bias of series inductance and transformer excitation inductance at the same time

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