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1. A method for enhancing an operation behavior of an inverter, said method comprising the steps of: calculating by a processor of the inverter during a startup phase of the inverter in the time domain and in real time instantaneously a capacitance, C of an AC capacitor of an AC-filter stage of said inverter for each electrical power supply phase of the inverter on the basis of a measured voltage signal and a measured current signal for the respective electrical power supply phase as a ratio between a root mean square DC-free quadrature current value and a root mean square DC-free voltage value on the basis of a predefined minimum number of voltage signal samples of the measured voltage signal and current signal samples of the measured current signal to compensate effects of harmonics in the frequency domain, wherein during the startup phase the AC-filter stage of the inverter is separated by a grid relay from a public or stand-alone power supply grid or from a backup system; and compensating by the processor of the inverter during a power feed in of electrical power by the inverter automatically an observed change of the calculated capacitance, C, of the AC capacitor of the AC-filter stage of said inverter over time by adjusting the AC current generated by the inverter for the respective electrical power supply phase to optimize a reactive current injection, wherein the power feed in of the electrical power by the inverter is started after closing the grid relay to the public or stand-alone powers supply grid or backup system.
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