LCO-FLL control for single-phase utility integrated single-stage solar PV system

摘要： This study presents a limit cycle oscillator-frequency locked loop (LCO-FLL) control for single-phase utility integrated single-stage photovoltaic (PV) system. The proposed topology increases the utility of the voltage-source converter (VSC), particularly in the absence of PV generation. It has the potential to load harmonics current mitigation. It estimates harmonic free load current accurately with low computational requirement due to the absence of cumbersome mathematical algorithm and transformation techniques. It provides reactive power compensation, both in the absence and the presence of PV generation, improves transient response during dynamics in load and varying irradiance conditions. The total harmonic distortions of utility current and utility voltage, compliance the limit of the IEEE-519 standard. The proportional–integral (PI) regulator regulates the DC-link voltage of VSC input to the reference DC-link voltage. The incremental conductance-based technique derives the reference DC-link voltage. The dynamic behaviour of the LCO-FLL-based control is improved using a feed-forward loop for the PV power sharing. It also reduces loading on the PI controller. Test results demonstrate satisfactory performance of LCO-FLL-based control.