Non-isolated three-port DC-DC converter and use method thereof

Abstract

The invention relates to a non-isolated three-port DC-DC converter and a method for using the same. The converter is applied to a photovoltaic battery/battery/DC microgrid, and is provided with three ports of a photovoltaic battery PV, a battery BT, and a direct current bus DC. It includes two boost circuits and a buck-boost circuit, a boost circuit is used to connect the photovoltaic cell and the DC bus, a boost circuit is used to connect the photovoltaic cell PV and the battery BT, and a boost-boost circuit is used to connect the battery BT and DC bus DC; the specific circuit composition is: the positive pole of the photovoltaic cell PV is connected to the inductance L ₁ After that, three branches are drawn, the first branch is connected to the switch tube S ₁ The drain of the switch tube S ₁ The source of the ground is grounded; the second branch is connected to the diode D ₁ the anode of the diode D ₁ The negative pole is connected to the DC bus DC; the third branch is connected to the diode D ₂ the anode of the diode D ₂ The negative pole of the switch is connected to S ₄ The drain of the switch tube S ₄ The source of the battery is connected to the positive pole of the battery BT; the positive pole of the battery BT is connected in series with the inductance L at the same time ₂ Then lead out two branches, one branch is connected to the switch tube S ₂ the drain.

Description

Technical field [0001] The invention relates to the technical field of power electronic energy conversion, in particular to a non-isolated three-port DC-DC converter. The converter is used in photovoltaic cells / battery / DC microgrid. Background technique [0002] With the increasing shortage of fossil energy sources and the increasingly serious environmental pollution problems, new energy sources are becoming more and more popular and have become a current research focus. New energy power generation is intermittent and random, that is, the output power is unstable, which makes it difficult to develop and utilize on a large scale. Microgrid with storage battery and multiple micro sources is an effective way and form for large-scale development and application of new energy. [0003] Solar energy is a green and renewable resource. Photovoltaic power generation is its main application form. Grid-connected photovoltaic power generation is the main way for large-scale solar energy appl...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiencies in energy flow and control of photovoltaic DC microgrids in the prior art, the technical problem to be solved by the present invention is to propose a non-isolated three-port DC-DC converter, which is three-port and has integrated The advantages of high precision, high conversion efficiency, and low cost can overcome the problems of many devices, large device volume, and low efficiency in the use of multiple traditional converters, and can realize energy flow from the DC bus terminal to the battery direction. Suitable for power flow between photovoltaic cells / battery / DC bus in DC microgrid

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