Stability Improvement of Onboard HVDC Grid and Engine Using an Advanced Power Generation Center for the More-Electric Aircraft

In the high-power settings of engine, such as maximum take-off, more power should be extracted from the high-pressure spool (HPS) than the low-pressure spool (LPS) to avoid the overspeed and potential instability of the HPS. However, as revealed in this paper, extracting more power from the HPS will degrade the onboard HVDC grid stability for the conventional single dc bus power generation center. To address this conflict, in this paper, an advanced power generation center (APGC) incorporating an extra back-to-back (BTB) converter is introduced to improve the stability for both engine and HVDC grid. The BTB converter connects the HP power generation channel and the LP channel, providing an additional power flow path between the HP channel and LP channel. A transfer function-based impedance model and a state-space model of the HVDC grid are proposed to study the HVDC grid stability. The analytical findings of the HVDC grid stability and stability improvement using the APGC architecture have been verified through simulation and experimental results.