Passivity-based stabilization method of DC microgrid considering negative impedance characteristic

In DC microgrid with increasing number of constant power loads(CPLs), conventional control is difficult to guarantee the stability and dynamic performance of the whole system. For this reason, this paper introduces a property of passivity theory and deduces the passivity-based stabilization criteria in DC microgrid. Based on this stabilization criteria, a passivity-based stabilization method considering the negative impedance characteristic of CPL is proposed. In the proposed method, band-pass filter (BPF) and resistive damping are employed to control the output impedance near the resonance frequency for each converter and to avoid voltage decline of DC bus in microgrid. Meanwhile, PID controller are utilized to ensure the passivity and dynamic performance simultaneously. Moreover, the relationship between control parameters and passivity is presented and discussed. The correctness and effectiveness of the proposed method is verified by the MATLAB/Simulink model under the most severe conditions.