Nonlinear control of Bi-Directional DC-DC converter in distributed photovoltaic energy storage system

With the rapid development of distributed photovoltaic energy storage system, the ability of tracking power reference is summarized systematically in source side and grid side.Firstly, this paper proposes a nonlinear affine model of the non-isolated bi-directional DC-DC converter in energy storage system, establishes the voltage tracking parameter transformation model, and gets the nonlinear state space descriptions on large signal modeling method.Then based on the state-feedback linearization conditions, the virtual output from the nonlinear state space descriptions to the state space descriptions after non-linear transformation is established.The controller can be designed by the analysis of the impact, which are the system parameters of second-order classical control system and the calculation of state-feedback coefficient in the state space.Finally, the results of the numerical simulation and experiment reveal that the control methods in this paper has the rapid and accurate ability of tracking power reference.It is has strong robustness under the conditions of DC-link voltage fluctuation, the load disturbance, and the inaccurate system parameters.The effectiveness of proposed method was verified by simulation and experiment results.