An Integrative Control Scheme for Boost-buck Inverter in Grid Connected Photovoltaic Systems

This paper addresses a new integrative control scheme for a boost-buck inverter, interfacing the photovoltaic array with the power grid. Based on dynamically tracking the maximum power point, two novel control methodologies are proposed to control the DC-bus and the output current for the inverter. First, introduced is a new linear cycle discrete control algorithm, realizing linear control for the DC-bus voltage and synchronously getting the reference current for the inner current loop with a little calculation. Then, to assure a good adaptability to noise and model uncertainty, the output current control scheme is chosen to be an auto-disturbance rejection control, not depending on precise mathematics model, thus, output current of PV system to the grid is with low harmonic distortion and unity power factor. Simulations and experiments are performed, and results show the system is of excellent robustness and effective.