Online Multi-cascade DC Converter Impedance Measurement Method Based on Multi-sine Signal Injection

Impedance characteristics of DC converters in multi-cascaded system are important parameters for the stability analysis of multi-cascaded system. Since the impedance characteristics usually vary over time with operation conditions, therefore, online impedance measurement of multi-cascaded DC converter is required for the adaptively adjustment for the stability of multi-cascaded system. However single disturbance source is adopted in existing methods for online impedance measurement, which requires multiple disturbance signal injection while obtaining the impedance characteristics of multi-cascaded DC converters. In order to realize the rapid online measurement of DC converters, a multiple disturbance sources online measurement method based on multi-sine signal injection is proposed. The design method of frequency, amplitude and phases of each component in multi-sine signal is proposed in order to obtain accuracy measurement results. At last, simulation is conducted to verify the effectiveness of proposed method.