Sparse quaternion-valued minimization based technique with pre-predictive PV control loop of distributed PV power generation system

This paper presents a sparse quaternion-valued minimization (SQVM) based control technique of a two-stage grid supportive photovoltaic (PV) power system with power conditioning capabilities. The grid side converter (GSC) is controlled by utilizing an SQVM control technique. The proposed algorithm enables the GSC to mitigate the load harmonics current and provides reactive power compensation at the point of common coupling (PCC). The proposed control is tuned to mitigate the DC offset error, harmonics current and to improve the frequency response of the proposed system. A DC link pre-predictive is incorporated to improve the dynamic response by reducing the burden on the outer Proportional-Integral (PI) voltage controller loop. Further, it is used to extract the fundamental component of load currents for generating the reference currents. An adjustable DC link voltage loop is incorporated in the proposed control technique to adapt the PCC voltage variation, which helps in minimizing the losses of the PV system. For real-time execution of the adjustable DC link voltage concept, the DC link voltage is adapted with a variation in the PCC voltage. The operation and control of the system topology are validated experimentally under various scenarios.