Due to the low inertia of the DC microgrid, the DC bus voltage is prone to drop or oscillate under disturbance. It is also challenging to supervise the stability of a DC microgrid since it is a highly nonlinear dynamic system with high dimensionality and randomness. To tackle this problem, this paper proposes a new method using ANN-aided nonlinear dynamic stability analysis for monitoring the DC bus voltage, which is combined with two steps. The first step is to establish six corresponding nonlinear accurate discrete iterative models of six switching modes of the PV-battery-load-based DC microgrid system, based on the Poincaré map theory, in order to judge the stability quantitatively with a promoted stability margin index. The second step is to use artificial neural networks (ANNs) to forecast the operating mode of the system when random changes occur in environmental circumstances and load power; this will aid the first step in being efficient and adaptable while determining stability cases. And the employed ANNs are trained with the datasets, including the circuit data, ambient temperature, irradiance, and load power, which are generated by MATLAB/Simulink simulation. Theoretical and simulation analyses are carried out under different operating conditions to validate the proposed method’s efficacy in judging the DC microgrid’s destabilizing oscillation and stable running.

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The stability of generator excitations and SVCs in power system with wide-area time-delay coordinating Control is investigated in this paper. A nonlinear time-delay Hamiltonian model of power system with SVCs is constructed and the Hamiltonian functional method is used to derive a delay-dependent steady stability criterion in term of matrix inequalities by constructing suitable Lyapunov-Krasovskii functional. Then the wide-area damping controller (WADC) and wide-area damping supplementary controller (WDSC) for the power system is designed based on the delay-dependent sufficient conditions. Four-generator eleven-bus power system is used to illustrate delay effect on inter-area mode damping. The performance of the proposed controller is verified by the results of simulation in time-domain, and it is proved that the method proposed in this paper is effective.

The research and development of Hamilton system have provided an effective approach for the nonlinear analysis and stability control of power system. It also plays an important role in the control of flexible AC transmission system. The application of Lagrange analytical mechanics can improve the realization of Hamilton system and the controller design. The model of single-machine infinite-bus system with TCSC is extended to an even-order system in this paper. On the basis of self-adjoint conditions the standard form of Hamilton realization is obtained with the theory of Lagrange mechanics. By non-conservative analytical mechanics theory, the system controller is designed and Matlab programming is realized on the single-machine infinite-bus system. The simulation effects of the designed controller and general controller under three-phase grounded short-circuit faults are compared, which verifies the effectiveness of the proposed control strategy in this paper. The construction of Hamilton function and design of the controller have a broad prospect of applications.