A quasi-z source step-down dc-dc conversion circuit

Abstract

The invention provides a quasi Z-source buck DC-DC conversion circuit, which comprises a voltage source, a quasi Z-source network, a second switch, a third inductor, an output capacitor and a load, wherein the quasi Z-source network comprises a first inductor, a second inductor, a first capacitor, a second capacitor and a first switch tube; the output capacitor and the load are taken as one part of the quasi Z-source network; the voltage source, the third inductor and the quasi Z-source network are sequentially connected in series; and the second switch is connected to the first inductor and the second capacitor of the quasi Z-source network in parallel. The overall circuit structure is simple; an output and an input are commonly grounded; when the duty ratio is close to 0.5, a very low step-down ratio can be achieved; and the circuit is free of a problem of a starting impulse current, and is free of a reverse recovery phenomenon in the process that a diode PN junction changes into a cut-off state from a conducting state in a general buck converter due to the absence of a diode. In addition, the converter also has buck-boost and two-way energy flow capabilities.

Description

technical field [0001] The invention relates to the field of power electronic circuits, in particular to a quasi-Z source step-down DC-DC converter circuit. Background technique [0002] In the LED centralized DC power supply system, in order to reduce line loss, high-voltage DC transmission is used. Since the driving voltage required by the LED is small, it is necessary to step down the DC high voltage of hundreds of volts. Due to the small voltage transformation ratio, the use of ordinary BUCK converters will cause problems such as large switching losses, low conversion efficiency, and serious electromagnetic interference, and usually there are diodes in the step-down converter. There is a reverse recovery phenomenon. However, the topology of the isolated converter is complex, the leakage inductance of the transformer causes energy loss, and the electromagnetic interference is serious. Contents of the invention [0003] The purpose of the present invention is to overco...

AI Technical Summary

Problems solved by technology

Due to the small voltage transformation ratio, the use of ordinary BUCK converters will cause problems such as large switching losses, low conversion efficiency, and serious electromagnetic interference, and usually there are diodes in the step-down converter. reverse recovery

However, the topology of the isolated converter is complex, the leakage inductance of the transformer leads to energy loss, and the electromagnetic interference is serious

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