Comparative Study of Grid-Following LCL-Filtered Inverters with Sampling Different Voltages

The grid-connected inverter is the key interface in the distributed power generation system. To realize a high- quality grid current of the inverter, at least, the sensors for one current and one voltage from so many available electric variables at the inverter output should be required for implementing the phase-locked loop (PLL) and current control. For the selection of the current sampling, many literatures have discussed the current control with the sampling of grid current, inverter-side current or capacitor current. For the selection of the voltage sampling, two voltages including the voltage at the point of common coupling (PCC) and the capacitor voltage can both be applicable. However, the comparisons of the two implementations have still not been well documented by literatures, and the influence of the selections of voltage sensor locations to the inverter control performances is still unclear. Therefore, this study aims to further compare the performances of grid-connected LCL-filtered inverters with different voltage sensor locations.