Cascaded multi-voltage unit DC-DC converter for photovoltaic system

Abstract

The invention discloses a cascaded multi-voltage unit DC-DC converter for a photovoltaic system. The cascaded multi-voltage unit DC-DC converter combines a boost unit structure of a multi-voltage unit, compared with a conventional boost converter, the boost performance is improved; compared with the boost unit of a conventional voltage doubler unit structure, the converter has superior boost voltage performance as the duty ratio increases. The cascaded multi-voltage unit DC-DC converter also combines a cascaded boost circuit structure, the voltage gain is further improved, the number of switching tubes S is not increased, the control difficulty of the system is not increased, and the electrical stresses of the switching tubes S and an output rectifier diode Do are not affected. In addition, the cascaded multi-voltage unit DC-DC converter also combines a leakage inductance clamp circuit structure, on the basis of using a coupled inductor to improve the boost capability of the converter,the energy of the leakage inductance of the coupled inductor is released, thus the circuit resonance problem caused by leakage inductance energy is avoided, and the efficiency of the circuit is alsoimproved.

Description

technical field [0001] The invention relates to a DC-DC converter, in particular to a cascaded multi-voltage unit DC-DC converter 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 parasitic parameters, v...

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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