Stability Enhancement of Bi-Directional Voltage Source Converters in
Modern Power Systems
Abstract
In future modern power systems, reliability and resilience could be an
extreme challenge caused by the stability issues of the bidirectional
power converters (BPCs). The non-linear dynamics of DC link voltage
(DCLV) of BPCs in interaction with the existing linear control schemes
may decrease the stability margin and cause operating-point-dependent
instability issues. Existing approaches may solve this issue by reducing
the DCLV control loop bandwidth, which considerably degrades the system
performance. To tackle this issue, first, the root cause of the
instability challenge is analytically investigated, and then, a
non-linear stabilizer control scheme based on Lyapunov theorem is
proposed. Considering the non-linear dynamic of the BPCs and the
interaction between dynamics of DC link voltage and AC currents in the
proposed stabilizer, it guarantees the stability of the converter in
both directions of power flow and the full range of loading conditions.
The performance of the proposed scheme is verified through simulation of
the system under various operating conditions, considering
uncertainties, disturbances, and short-circuit events, and comparing it
with that of prevalent controllers.