A Triple Active Bridge Converter with Integrated MPPT and Ramp Rate Control Function

In response to the carbon peak and carbon neutrality goals, photovoltaic power generation, as a more environmental-friendly way, is paid close attention and develops rapidly to generate electricity. However, due to the change of meteorological conditions, the output of solar photovoltaic (PV) system fluctuates and leads to the bad quality of power. To address this issue, a Triple Active Bridge (TAB) converter is used to connect PV-battery system to the grid and a variable step size Perturbation and Observation (VSS P&O) Maximum Power Point Tracking (MPPT) algorithm based on power prediction is proposed in this paper. Meanwhile, battery system is employed with Ramp Rate Control to restrain the photovoltaic power fluctuations. The advantages of using the TAB converter lie in its galvanic isolation and high-efficiency power conversion. Compared with the traditional P&O or Incremental Conductance method, power prediction reduces the possibility of wrong tracking direction in the process of MPPT and the variable step size ensures the system to track the maximum power point quickly and accurately. Under this method, the result achieves smooth power output and help integrate PV-battery system into the grid in an efficient way. The proposed methods are verified through simulations based on real solar irradiance data.