DQ Impedance Measurement Method for a Three-Phase Power Converter System

This paper proposes an impedance measurement method in the dq domain for a three-phase power converter system. The proposed method comprises three steps. First, the perturbation of a frequency response analyzer (FRA) is generated as a dq domain signal, which is inversely converted to three-phase signals using a digital signal processor (DSP) and applied to an actual system as series voltage or shunt current excitations. Second, the three-phase current or voltage responses are measured and reconverted to the original dq domain signals using the DSP. Third, the impedance characteristics are obtained using the FRA based on the derived ratios between the excitation and response signals. The proposed method is validated by comparing the analytical and experimental results. © 2022 The Institute of Electrical Engineers of Japan.