Investigation on the Development of a Sliding Mode Controller for Constant Power Loads in Microgrids

Abstract

Abstract:To implement renewable energy resources, microgrid systems have been adopted and developed into the technology of choice to assure mass electrification in the next decade. Microgrid systems have a number of advantages over conventional utility grid systems, however, they face severe instability issues due to the continually increasing constant power loads. To improve the stability of the entire system, the load side compensation technique is chosen because of its robustness and cost effectiveness. In this particular occasion, a sliding mode controller is developed for a microgrid system in the presence of constant power loads to assure a certain control objective of keeping the output voltage constant at 480 V. After that, a robustness analysis of the sliding mode controller against parametric uncertainties was performed and the sliding mode controller's robustness against parametric uncertainties, frequency variations, and additive white Gaussian noise (AWGN) are presented. Later, the performance of the proportional integral derivative (PID) and sliding mode controller are compared in the case of nonlinearity, parameter uncertainties, and noise rejection to justify the selection of the sliding mode controller over the PID controller. All the necessary calculations are reckoned mathematically and results are verified in a virtual platform such as MATLAB/Simulink with a positive outcome.

Coordinated Control Strategies for a Permanent Magnet Synchronous Generator Based Wind Energy Conversion System

“…The ripple components of the generator speed and the output power are also eliminated and the parameters are subjected within the rated value. Figure 7 shows the pitch angle control strategy [26][27][28][29][30][31][32][33].…”

Sliding Mode Controller and Lyapunov Redesign Controller to Improve Microgrid Stability: A Comparative Analysis with CPL Power Variation

“…To elucidate this method, schematic models of storage-based real power compensation and reactive power compensation techniques (load side) are presented below in Figures 4 and 5 [18]. From the dq-axis models demonstrated above, the combined state space equation of the espoused load side compensation technique is shown in Equation (1) [19].…”

“…It can be noted with ε approaching zero, the function tanh( ω i ε ) gets converged to the sgn( i ) function, which is discontinuous. By substituting Equation (19) in Equation (17) we obtain:…”

“…For direct current (DC) microgrid, several researches are reviewed at [14][15][16][17]. Sliding Mode Control (SMC) and Lyapunov Redesign Control (LRC) techniques are two of the most prominent nonlinear control techniques used to improve microgrid stability [18,19]. Prior to this, several studies have been carried out on the SMC technique.…”

“…The sliding surface is defined by σ = 0, and after the limited time when the trajectories of the system have reached the surface, the sliding mode along the surface begins. From the dq-axis models demonstrated above, the combined state space equation of the espoused load side compensation technique is shown in Equation (1) [19].…”