Impedance Measurement of Grid-Tied Inverter With Deviate-Frequency Harmonic Current Injection

Abstract

The output impedance of the grid-tied inverter is an important parameter to determine the stability of its operation. In this paper, the influence of inverter modulation and dead zone phenomena on impedance measurement is analyzed, and an impedance measurement method based on deviate-frequency harmonic current injection is proposed. Simulation results are provided to demonstrate the feasibility and the performance, and the results show that the new method can accurately measure impedance amplitude and angle of inverter in broadband frequency.