Harmonic-domain impedance modeling and stability analysis of three-phase inverter

In the DC distributed network, the inverter is often integrated with an electromagnetic interference (EMI) filter in the DC-side to attenuate the higher frequency noise. However, the interaction between the filter and the inverter may lead to cascaded stability problems. To solve this problem, this paper utilizes the harmonic linearization method to model the input impedance of the three-phase inverter while taking specific high-order harmonics into consideration. Moreover, to verify the accuracy of the derived impedance model, the frequency sweep impedance measurement method is adopted. And the comparison between dq-domain impedance and harmonic-domain impedance is discussed, proving that the proposed impedance has higher accuracy. Finally, through the stability analysis and verification of designed cascaded system, the correctness of the proposed model is further proved.