The existing research on hybrid energy storage system (HESS) stability mostly focuses on small-signal stability analysis methods. However, when large-signal disturbances occur, the intrinsic nonlinearity of the HESS becomes inevitable so that the small-signal studies are no longer valid, which is beyond the scope of small-signal stability analysis. To address this problem, a large-signal stability analysis method of the HESS is proposed based on the estimation of domain of attraction (DOA). This method can not only analyze the asymptotic stability of the operating point, but also answer the question of how large deviations from the operating point can be tolerated by the system. Specifically, the state space model and Takagi-Sugeno (T-S) fuzzy model of the whole system are first constructed. By using linear matrix inequality (LMI) and Lyapunov’s method, the DOA of the system at the operating point is estimated, and the large-signal stability of HESS is analyzed. On this basis, the influence of system parameters (e.g. virtual resistance, virtual inductance and PI regulators) and load power on the large-signal stability are studied, and the dominant parameters affecting the large-signal stability of the HESS is clarified, which provides a practical guiding basis for the parameter optimization design of the HESS to ensure the safe and stable operation of the system under extreme load switching conditions. The simulation results verify the feasibility and effectiveness of the proposed large-signal stability analysis method and the correctness of the analyzing results.

With a large number of constant power loads (CPLs) connected to the DC microgrid (MG), the injected negative impedance drastically deteriorates the stability of the DCMG. To address this issue, a stabilization strategy for the DCMG with CPLs fed by the four-switch Buck-Boost (FSBB) converters is proposed in this paper. Due to the adopted DC machine technique, a virtual capacitor is paralleled to the output port of the FSBB converter to support the bus voltage in the presences of CPL power changes. The stability of the system is analyzed based on the Middlebrook impedance stability criterion, and the effectiveness of the proposed control strategy is verified by MATLAB/Simulink simulation.

In the more electric aircraft (MEA) power system, the voltage stabilization of the interface three-phase rectifier is difficult to be achieved due to the wide range varying frequency and the unbalanced amplitude and phase of the output voltage of the AC generator. In this article, an advanced voltage control strategy based on the techniques of the dynamic phase voltages reconstruction and the improved proportional resonant (PR) regulation is proposed. Thanks to the proposed dynamic phase voltages reconstruction algorithm, the phase-locked loop (PLL) is not required, avoiding the risk of PLL instability in the presence of wide range frequency fluctuations. By integrating the improved PR regulator, the error steady-state control of the currents in αβ frame is guaranteed and the negative sequence harmonics are suppressed, which greatly reduces the reactive power and, hence, improves the power factor. Some simulations have been carried out to validate the effectiveness of the proposed strategy.