Research And Design Of Solar Charge Controller Based On Three-phase Interleaved Synchronous Buck

Solar energy, as a renewable, clean, non-polluting new energy, can solve those problems such as environment pollution, energy crisis and so on. However, the output of the solar power is not stable and its efficiency is low by the influences of temperature and lighting. To make full use of solar power and provide sufficient power for load, it is necessary to insert a converter behind solar photovoltaic so that the most power point trace(MPPT) can be achieved. Therefore, it is meaningful to research and design the high-performance charge controller.Firstly, the basic principle, equivalent circuit and output characteristics of solar photovoltaic are introduced; the charge and discharge characteristics of lead-acid battery are analyzed. An improved algorithm of MPPT is implemented based on the comparison of several common MPPT algorithms.Secondly, by analyzing the commonly used topologies for solar conversion and three-phase interleaved synchronous technology, three-phase interleaved synchronous buck is chosen as main circuit. In the control system, the single chip dsPIC33FJ16GS502 is used, the four-stage charging method is applied to realize intelligent switching among different charging modes. For the main charging stage, the method combining with the improved perturbation and the incremental conductance is used. The PI algorithm is used in the stage of constant voltage charging.Finally,an experimental platform was set up, hardware and software design of solar charge controller have been completed. C language has been used for soft program, and the intelligent charging control was achieved. Solar charge controller works well, the experimental results indicate that this system can track the maximum power point quickly and work on that point stably when the environmental condition changes, and thus the efficiency of PV array and converter can be improved, the life span of battery can be prolonged.