Voltage control for uncertain stochastic nonlinear system with application to energy Internet: Non-fragile robust H∞ approach

A Class of Control Strategies for Energy Internet Considering System Robustness and Operation Cost Optimization

“…Based on previous studies [23,33], P HP , P PHEV and P ER12 are obtained by the following equations:…”

“…For instance, in [21], both H ∞ and µ-synthesis approaches are utilized to regulate AC bus frequency deviations in an off-grid MG. A descriptor system H ∞ approach has been applied in autonomous MGs to improve signal stability [22]. In [23], the issue of voltage control in an EI scenario is formulated as a non-fragile robust H ∞ control problem regarding an uncertain stochastic nonlinear system, and it is solved via a linear matrix inequality approach. Robust H ∞ load-frequency control (LFC) in a hybrid distributed generation system has been studied in [24].…”

“…For robust control problems discussed in e.g., [21][22][23][24], H ∞ performance has been focused. When both H 2 and H ∞ performances are considered simultaneously, the associated issues are called mixed H 2 /H ∞ control problems.…”

“…As is mentioned above, some existing works only investigate either optimization of operation cost and energy management (e.g., [16][17][18][19][20]), or robustness against internal instability and external disturbances (e.g., [21][22][23][24]) of MG systems. In this paper, this is the very first time that both two aspects are considered simultaneously in the field of EI, rather than in conventional energy systems.…”

“…Our work can be viewed as an extension as well as a generalized version for the ones focusing on single islanded or grid-connected MG. Comparing this paper with some existing ones adopting a time domain approach (e.g., [7,23,25]), our work formulated in the frequency domain has the advantage that it is convenient to be implemented in actual dynamic situations. With the proposed controller, the following targets are achieved simultaneously: (1) the system robustness against parameter uncertainty and external disturbance is achieved; (2) the tracking error is a controller to a relative low level; (3) the bottom-up energy management principle is achieved, such that an autonomous power balance in each MG is achieved with priority; (4) the cost involved by power delivery from PG to MG has been considered; (5) the controllable devices in MGs are utilized rationally, and the situation of over-control is avoided; (6) considering different preferences of the system manager, the importance of each control target can be adjusted by changing the size of its corresponding weighting coefficient; and (7) in simulation results, it is shown that the proposed controller performs better than the conventional ones do.…”