Cascade type buck-boost converter input side current control method

Abstract

The invention discloses a cascade type buck-boost converter input side current control method and belongs to the technical field of power electronics. The cascade type buck-boost converter input side current control method can complete control based on comparison between an input voltage and an output voltage of a converter. When the input voltage is lower than the output voltage, a switch tube of a boost converter is constantly conducted, and a first current control scheme is utilized to obtain a conduction duty ratio of the switch tube of the boost converter; and when the input voltage is higher than or equal to the output voltage, a switch tube of a buck converter is constantly cut off, and a second current control scheme is utilized to obtain a conduction duty ratio of the buck converter. The two switch tubes of the cascade type boost converter and the cascade type buck converter can be prevented from simultaneously working in a high-frequency state, system consumption is reduced, effective current control technology can be matched with a voltage boosting stage and a voltage reducing stage, and good input and output performances are achieved.

Description

technical field [0001] The invention discloses a current control method at the input side of a cascaded buck-boost converter, which belongs to the technical field of power electronics. Background technique [0002] In the past 20 years, power electronic technology has developed rapidly, and various power electronic devices have been widely used in chemical industry, communication and other fields. They are divided from the form of electric energy conversion. Such converters include DC-DC (referred to as DC-DC) conversion AC-DC (AC-DC) converters, and DC-AC (DC-AC) converters. If it is divided according to the size relationship between the input and output voltages, it includes step-up type (or called Boost type), step-down type (or called Buck type) and step-up-buck type. Among them, the step-up-buck converter can minimize the difference in sampling values ​​between the input and output voltages, reduce the voltage stress of circuit components and improve system efficiency,...

AI Technical Summary

Problems solved by technology

The dual-voltage and dual-current-loop control scheme has the defect that the intermediate stage capacitor voltage must be higher than the output voltage, which increases the voltage stress of the switch tube. The single-voltage loop and dual-current-loop control scheme has the problem of designing three loops. more difficult to design

In the time-sharing operation mode of two switching tubes, the average current control scheme adopted in both the step-up and step-down stages is more suitable for the current control in the step-up stage, but it is not a good choice in the step-down stage. Therefore, in order to ensure The control system is stable, so we have to make more constraints on the hardware circuit parameters, such as increasing the filter inductance value

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