TMS320F2812-based Bidirectional DC-DC Converter for Photovoltaic Power Generation System

Issuing time:2023-05-17 09:51

Solar photovoltaic power generation is a major trend of energy utilization in the future, and it is gradually widely used. As an important power conversion device in photovoltaic power generation system, bidirectional DC-DC converter has attracted more and more attention from researchers at home and abroad. The bidirectional power conversion is a complex multi-input and multi-output nonlinear system, and the traditional analog control technology can not meet the fast multi-characteristic control. Therefore, the research on the fully digital control bidirectional DC-DC converter for solar photovoltaic power generation has very important academic significance and application prospect.


The bidirectional DC-DC converter is divided into two parts: the main circuit and the control system. The main circuit realizes the bidirectional flow and transformation of energy, and the control system realizes the voltage rise and fall characteristics of the photovoltaic system and the control algorithm such as the charging mode, discharge mode and fast switching of the battery in the photovoltaic system.


The main circuit structure of bidirectional DC-DC converter


The main circuit of bidirectional DC-DC converter is divided into two categories: isolated type and non-isolated type. The isolated main circuit topology is mainly full bridge or half bridge circuit, which has obvious disadvantages, such as large number of switches, complex control and relatively low efficiency. The non-isolated type represented by the Boost/Buck bidirectional DC-DC transform topology overcomes these shortcomings [1]. Therefore, the non-isolated Boost/Buck bidirectional DC-DC converter topology is adopted as the main circuit structure of the converter.


The circuit topology is shown in Figure 1, where UBAT is the low-voltage side of the battery pack and UVBUS is the high-voltage side of the solar array. In the figure, S and /S are power switching tube IGBT, D and /D are continuous current diodes, C1 and C2 are filter capacitors, L are energy storage inductors, L0 and /L0 are high-frequency choke rings, D1, D2, L1, C0 and /D1, /D2, /L1, /C0 constitute Boost and Buck soft converter branches respectively.