DC power distribution system is converter- dominated

such that the oscillation and instability caused by multi-scale interactions between the source and load subsystems is prone to occur. Wideband impedance measurement is an important means to obtain and analyze the system impedance characteristic and interactive stability. In order to meet the injection-based impedance measurement requirements of multi-voltage level DC distribution systems

the principle of impedance measurement based on shunt harmonic disturbance injection is introduced first in this paper

and the topology of DC-blocking capacitor-based harmonic disturbance injection circuit is analyzed. Then

focusing on enhancing the output performance and the cost-effectiveness of the DC-blocking capacitor full-bridge circuit solution

a matching circuit with the capabilities of high-order filtering

second-order segmented buffer access

and fault current limiting is designed. A control strategy for single/multi- frequency harmonic disturbance injection without auxiliary power supply is proposed. Furthermore

taking the frequency range and maximum amplitude of impedance measurement as design inputs

parameter selection criteria for both the matching circuit and multi-coupling control loops are established. Finally

time-domain simulations and low-power prototype experiments validate the effectiveness and economic of the proposed disturbance injection device and its control strategy.