Research And Design Of Charger Controller IC In Independent Photovoltaic Power Generation System

The 'green power' is a kind of pollution-free and inexhaustible power. Among all kinds of 'green power', the solar energy is the most promising one. The independent photovoltaic power generation system is the primary method to utilize solar energy. In order to keep the whole system stable and efficient, the module of power storage is very important. Most of the power storage modules used in photovoltaic power generation systems are VRLA batteries. Because of the strict requirements for charging conditions, an advanced charger controller for VRLA batteries is pivotal for the whole system.It is difficult to satisfy all kinds of VRLA batteries with constant charging current and voltage provided by traditional charger controllers. Based on the profound analysis of VRLA batteries' charge properties in four charge modes, this paper proposed a high-performance, low-power, programmable and self-adaptive charger controller for VRLA batteries.Cooperating with MCU and DC-DC convertor, this controller can provide different kinds of charging currents and voltages to different VRLA batteries. The current loop is used as internal control loop and voltage loop is used as external control loop. As the proposed controller improves the charging efficiency and stability, the life of VRLA batteries was extended and so does the whole photovoltaic power generation system.Based on the analysis above, the function of each module and the structure of the system were presented. Each module's function analysis, schematic and simulation result were also discussed. The chip was fabricated in BCD technology and the experimental results consisted with the specifications well.