Wide-range input type boost-buck three-level DC converter for photovoltaic power generation

Abstract

The invention discloses a wide-range input type boost-buck three-level DC converter for photovoltaic power generation. The wide-range input type boost-buck three-level DC converter comprises a three-level Buck DC converter, wherein the post stage of the three-level Buck DC converter is connected in parallel with a quasi-Z-source liquid crystal display (LCD) three-end impedance network, the quasi-Z-source LCD three-end impedance network comprises a first inductor, a second inductor, a first energy storage capacitor, a second energy storage capacitor and a first diode, and the post stage of the quasi-Z-source LCD three-end impedance network is connected in parallel with a three-level Boost DC converter. In the wide-range input type boost-buck three-level DC converter, the quasi-Z-source LCD three-end impedance network is utilized, the front stage of the quasi-Z-source LCD three-end impedance network is connected in parallel with the traditional three-level Buck DC converter and the post stage of the quasi-Z-source LCD three-end impedance network is connected in parallel with the traditional three-level Boost DC converter to form a wide-gain three-level Buck-Boost DC converter topology, the Boost capability of the topology is improved, and the voltage stress borne by an original power device is reduced by half.

Description

technical field [0001] The invention relates to a DC converter, in particular to a wide-range input type buck-boost three-level DC converter for photovoltaic power generation. Background technique [0002] With the development of economic globalization, people's living standards are gradually improving, and the demand for energy is also increasing. However, the depletion of traditional energy sources, such as oil and coal, and the environmental pollution caused by the extensive use of fossil fuels have made people Make greater efforts to explore the use of new energy technologies. Therefore, various new energy sources such as solar energy, wind energy, tidal energy, and nuclear energy have been developed and utilized. These new energy sources have their own characteristics, but solar energy attracts the most attention because it is clean, pollution-free, abundant and renewable. It is believed that with the continuous advancement of technology, the further reduction of costs...

AI Technical Summary

Problems solved by technology

[0004] Although the traditional Buck-Boost converter has the functions of step-up and step-down and has a simple structure, if it is applied to photovoltaic grid-connected occasions, there will be problems such as high voltage stress of power devices and different voltage input and output polarities

Although the polarity of the voltage input and output of the dual-tube Buck-Boost converter is the same, the voltage stress on the power device is large. , affected by the parasitic parameters of the circuit, its actual gain is narrow, and the power switch is easy to operate in an extreme duty cycle state, resulting in a peak current and reducing efficiency, and even causing the risk that the power switch cannot be effectively turned off

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