An Inner-Loop Control Method for the Filter-less, Voltage Sensor-less, and PLL-less Grid-Following Inverter-Based Resource

A comparative analysis of power pulsating buffer architectures for mitigating high‐frequency and low‐frequency ripple in PV microinverter applications

“…Automatic power decoupling (APD) investigated in [35] is not implemented, as it is required that the PPB operate independently from the microinverter controller therefore necessitating a DPD framework. It should be noted that it is possible to potentially remove the SOGI-PLL as done in [36] by assuming that the microinverter in Figure 2 both may forego the LC electromagnetic interference (EMI) filter when the impedance at the point of common coupling (PCC) between the converter output and grid system provides acceptable attenuation of differential-mode emissions, thereby ensuring that the microinverter output voltage is already the same as the grid voltage. This assumption is however not the valid for the larger microinverter research considered due the PCC impedance not being sufficient to directly meet emission requirements, necessitating the installation of an EMI filter to meet total harmonic distortion (THD) requirements, and due to it being required that the microinverter must additionally operate in islanded mode connected to a microgrid.…”