| Popis: |
With the development of renewable energy generation technology, the DC power distribution system (DPSs) commonly contains various buses with different voltage levels. Under this circumstance, it is much more challenging to carry out stability analysis for such multi-voltage level DPSs. According to the mainstream methods, the multi-voltage level DPSs are directly equivalent to the source subsystem and load subsystem. However, this kind of impedance equivalence and stability analysis hide each voltage-level DC bus's impedance characteristic. When the impedance instability occurs, it will be challenging to identify the instability DC bus in DPSs. In this paper, a stepwise impedance analysis method for multi-level DPSs is proposed. The impedance stability is firstly implemented in the lowest voltage level of DPSs with the stability criterion. If the lowest voltage level of DPSs is stable, then the voltage level's impedance is converted to the upper voltage level through an interface converter. With the step-by-step stability analysis and equivalent impedance calculation, the multi-voltage level DPSs can be guaranteed if all of the voltage levels are derived stable. Lastly, the effectiveness of the proposed method is validated by simulations in Matlab/Simulink. |
