Sensor reduction of a PV-grid tied system with tripartite control based on LCL filter

Abstract

This paper deals with a tripartite control based on LCL-filter for a single-stage solar photovoltaic (PV) interconnected three-phase grid-tied system. This work proposes a novel tripartite control for LCL-filter based on sensing capacitor side voltage utilising two sensors. Conventionally, the control algorithm requires six sensors for sensing the inverter-side inductor current, capacitor side voltage, and grid-side inductor current. However, in this work, to execute the tripartite control algorithm, the only voltage across the filter capacitor need to be sensed. The voltage across the filter capacitor estimates inverter-side inductor current and grid-side inductor current. The proposed algorithm offers the advantage/benefit in reducing size, weight, and implemented cost. As an outcome, the reduction in the complexity of the hardware takes place. The implemented system is analysed for parametric variation to ensure the stability and robustness of the system. The system response is observed under digital control delay variation. The proposed method offers a cost-effective solution for meeting grid regulation. The implemented system is extensively tested and validated by simulation in the MATLAB/Simulink platform. The justification of the system is carried out by experimental results obtained from the prototype designed in the laboratory.