Three-port integrated converter for photovoltaic energy storage system, and control method

Abstract

The invention discloses a three-port integrated converter for a photovoltaic energy storage system; the converter comprises two switch tubes, three capacitors, three diodes and three inductors, wherein the three capacitors are connected with a storage battery, a photovoltaic module and a load in parallel respectively. The first switch tube, the second switch tube, the first diode, the second diodeand the first inductor form a Buck-BOOST circuit, so that bidirectional flow of energy of the storage battery and the photovoltaic module is realized; and the first switch tube, the third diode and the second inductor form a Boost circuit, so that the energy flow of the photovoltaic assembly to the load is realized. According to the converter, the power switch is integrated through multiplexing of the switch tubes, so that a switch tube and a driving module are reduced, the integration degree of the converter is improved, and the cost is lowered. The invention further discloses a control method of the converter. The first inductor is controlled to work in a CCM mode, and the maximum power point tracking control of the photovoltaic module is realized by adopting a variable duty ratio; andthe second inductor is controlled to work in a DCM mode, and load constant-voltage control is realized by adopting variable-frequency control.

Description

technical field [0001] The invention belongs to the technical field of converter control, and in particular relates to a three-port integrated converter used in a photovoltaic energy storage system and a control method. Background technique [0002] With the increasing energy crisis and environmental pollution, photovoltaic power generation technology has attracted extensive attention from governments and enterprises in various countries. Due to the volatility and randomness of solar energy, photovoltaic power generation systems need to be equipped with batteries to store and adjust electric energy to ensure continuous and stable power supply to loads (such as DC converters, inverters, DC microgrids, etc.). Therefore, the photovoltaic energy storage power generation system has three ports of photovoltaic, battery and load, and usually uses two converters of Boost photovoltaic interface and Buck / Boost bidirectional energy storage interface to realize the maximum power point t...

AI Technical Summary

Problems solved by technology

This structure can effectively realize the energy management and control of the photovoltaic energy storage system, but there are disadvantages such as a large number of components, large volume and weight, and low overall efficiency.

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