Modularized photovoltaic direct current boost converter with low input current ripple, high gain and low loss

Abstract

The invention discloses a low-input-current-ripple high-gain low-loss modular photovoltaic direct-current boost converter, and belongs to the technical field of power generation, power transformation or power distribution. The converter comprises N isolated photovoltaic sub-modules and N-1 LC power balancing units. The isolated photovoltaic sub-module comprises a photovoltaic cell panel and a current source type dual-active bridge converter with a buck-boost characteristic, the current source type dual-active bridge converter with the buck-boost characteristic is adopted to reduce input and output current ripples, the voltage gain is high, and the isolated photovoltaic sub-module is suitable for a wide voltage gain occasion. And the loss of the converter is greatly reduced due to relatively small current stress and soft switching working characteristics. The photovoltaic sub-modules reuse devices in secondary full-bridge circuits, independent MPPT control of the photovoltaic sub-modules is realized by controlling a phase shift angle between primary and secondary circuits, power transmission between adjacent sub-modules is realized by controlling a phase shift angle between secondary full bridges of the adjacent sub-modules, and power balance between the sub-modules is realized. The number of used switching devices is reduced, and cost is greatly reduced.

Description

technical field [0001] The invention relates to the technology of photovoltaic multi-port DC converters, in particular to a photovoltaic multi-port DC grid-connected system that prolongs the service life of photovoltaic panels under unbalanced output power of photovoltaic panels, and discloses a modular photovoltaic system with low input current ripple, high gain and low loss A DC boost converter belongs to the technical field of power generation, transformation or distribution. Background technique [0002] In the renewable energy power generation system, high-voltage direct current (HVDC, High-Voltage Direct Current) has the advantages of less loss, better stability, and no need for reactive power compensation, which is incomparable in large-capacity long-distance transmission and new energy power generation. The advantages and broad application prospects of the distributed photovoltaic power generation system have become one of the main ways of new energy power generation...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned background technology, to provide low input current ripple, high gain and low loss modularized photovoltaic DC boost converter, and for the IIOS converter composed of multiple photovoltaic sub-modules, adopt the buck-boost characteristic The current source dual active bridge converter is used as the boost unit of each photovoltaic sub-module, and the power equalization unit is connected in series between the output terminals of each photovoltaic sub-module. The phase shift angle realizes the independent MPPT control of each photovoltaic sub-module. By multiplexing the switching tubes in the secondary full bridge of each photovoltaic sub-module and controlling the phase shift angle between the secondary full bridges of adjacent sub-modules, the adjacent sub-modules are realized. Power transmission achieves the invention purpose of increasing the gain of the converter while reducing the turns ratio of the transformer winding and reducing the loss while reducing the input current ripple, and solves the problem that the existing IIOS system is large in size, high in cost and has no input current ripple and output Gain optimization technical issues

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