Two-capacitor-clamped multi-bootstrap cascaded dc-dc converter for photovoltaic systems

Abstract

The invention discloses a multi-bootstrap cascade DC-DC converter having two capacitance clamping positions for a photovoltaic system. Two capacitance leakage inductance clamping circuit structures are integrated; on the basis that the boosting capability of the converter is improved through a coupling inductor, leakage energy of the coupling inductor has a release loop; the circuit resonance problem due to the leakage energy is avoided; simultaneously, the efficiency of the circuit is also increased; a cascade boost circuit structure is integrated; therefore, the voltage gain is further increased; simultaneously, the number of switching tubes S is not increased; the control difficulty of the system is not increased; furthermore, the electrical stress of the switching tubes S and an outputrectifier diode D<o> cannot be influenced; the boost unit structure of a multi-bootstrap unit is integrated in the invention; compared with the traditional boost converter, the boosting performance is improved; and, compared with the boost unit of the traditional single-bootstrap unit structure, along with increasing of the duty ratio, the converter has excellent boost voltage performance.

Description

technical field [0001] The invention relates to a DC-DC converter, in particular to a multi-bootstrap cascaded DC-DC converter clamped by two capacitors for a photovoltaic system. Background technique [0002] With the depletion of traditional fossil energy and the deteriorating environment of human beings, the development of clean renewable energy is imminent. All countries in the world are committed to the research and development of new energy applications, of which solar energy and wind energy have been obtained a wider range of applications. However, for these systems, how to operate grid-connected and meet the high voltage requirements in the grid is still the most important issue. At present, a large number of boost converters have been developed to meet these applications. Among different converters, the traditional BOOST converter can theoretically increase the voltage gain by increasing the duty cycle. However, in practical applications, due to the limitation of ...

AI Technical Summary

Problems solved by technology

However, in practical applications, due to the limitation of parasitic parameters, very high voltage gain cannot be achieved

If a cascaded topology is used, the problem of low efficiency caused by the increase in the number of devices will be highlighted again.

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