FFS modulated VSC with different phase‐shifted 12‐pulse configured transformers for grid integrated large‐scale solar PV plant

Abstract

The requirement for high capacity power conditioning unit (PCU) has increased for application in large-scale solar photovoltaic (PV) plant for optimisation of the balance of system cost. For high power applications, one of the most important criteria for designing of PCU is to have lower switching losses to minimise the heat generated in the power switching devices. Conventionally, PCU utilises traditional two-level or three-level voltage source converter (VSC) topology with high-frequency switching techniques and due to this, they have lower conversion efficiency and higher device switching losses. In this study, fundamental frequency switching (FFS) modulated three-level neutral point clamp (3L-NPC) VSC is used for MW scale PCU, as they have lower switching losses, higher conversion efficiency and higher AC/DC voltage ratio. The 3L-NPC VSC generates lower order current harmonics, which are mitigated by using different phase-shifted 12-pulse PCU transformers located at different pooling location inside solar PV plant. The PV plant configuration for a 40 MW (AC) plant capacity is developed in the Matlab/Simulink environment and implemented in real-time simulator OPAL-RT to validate the proposed concept. Harmonics, steady-state and dynamic performances are demonstrated at constant and changing solar irradiance levels.

Fuzzy logic controller-based enhancement for grid-connected large-scale PV systems

“…Incorporating a defuzzification module, the fuzzy information emanating from the inference mechanism undergoes a transformative conversion, thereby culminating in a transition from the domain of fuzzy values to a realm of non-fuzzy, crisp information. This non-fuzzy information is endowed with practical utility, serving as a coherent input for the process under control [116][117][118][119][120]. Through this procedural transformation, the inherent ambiguities ingrained within the fuzzy information are transcended, equipping the control system with actionable insights derived from the nuanced amalgamation of expert knowledge and domain-specific inference.…”