Improved robust‐mixed‐norm‐based controller for grid‐tied PV systems under voltage disturbances

Abstract

The grid-tied solar photovoltaic system requires a multiobjective control approach for performing the dual operation of active power transfer at unity power factor and harmonic filtering. In this context, this study proposes an improved robust-mixed-norm (RMN) filter-based multiobjective control strategy for integrating the solar photovoltaic system with the utility grid. The standard RMN filtering control exhibits slow convergence, requires large sampling time and involves high computational cost. Therefore, a switching parameter is designed to toggle between least mean square and least absolute deviation for extracting the benefits of both filtering techniques as per requirement. The switching parameter will also help in minimising the computational intensiveness during hardware implementation and successfully confronts the conflict between convergence speed and steady-state misadjustment in the presence of outliers. The proposed control is implemented with the help of multiple delayed input vectors to extract the fundamental weight component from the non-sinusoidal load current. In addition, the effects of grid voltage distortion and imbalance have been detached by using complex vector filter-based synchronisation technique. The practicality of the proposed multiobjective approach has been verified under different operating conditions of supply and load through both MATLAB/Simulink tool and low-cost microcontroller-STM32F407VGT6-based laboratory prototype.