A new impedance measurement method based on high frequency compensation

Impedance is very important in Micro-grid and other distributed power system based on power electronics because of the close relationship between impedance and stability. This paper presents a new current injection method for impedance measurement. Sinusoidal amplitude modulation is a method to shift signals to different frequency bands. A signal with large frequency bandwidth and small amplitude attenuation can be obtained by superposing square pulse signals after sinusoidal amplitude modulation. When the superposed signal is injected to the system as a current source, impedance information in the frequency range of interest can be calculated with short time cost and high accuracy. The simulation results demonstrate the effectiveness of this method.