Abstract
PV-based renewable energy systems are integrated in microgrids (MGs) throughout power electronic converters. During external disturbances of abrupt load variation and PV generation fluctuation, controllers play the most key role in regulating the system performance. In this paper, a proposed combination control method of model predictive control (MPC) and sliding mode control (SMC) for moderating the power converters is presented. The interlinking inverter is controlled via applying MPC while DC-DC converter is controlled by SMC. MPC is well known as most reliable and modern approach for non-linear systems to compensate noise and handle modeling inaccuracies for efficient load voltage profile. On the other hand, SMC is considered as the most stable controller with highly robust operation for DC-DC converters. Intermittency nature of renewable energy systems and abrupt load variation have a severe impact on load voltage quality. Keeping in view the sophisticated control attributes of MPC and SMC, inner and outer control loops with primary droop control are designed for interlinking converter by using MPC while SMC is designed for the DC-DC boost converter. Controller performance is analyzed through simulations with fluctuating generation, and variable loads. Unlike conventional cascaded PI controller, proposed MPC strategy is simple, robust with fast dynamic response.

Abstract
Future power system depends on penetrating more renewable energy to fulfill the drastic increase in energy demand with reduced carbon emission. Wind energy integration is increasing in worldwide each year. To efficiently investigate a quality voltage for AC loads under wind speed variations, a combined control strategy is proposed in this paper. It consists of PI and model predictive control (MPC) for the three-phase rectifier and interlinking inverter, respectively. The controlled rectifier ensures a constant DC-bus voltage under variable wind speed, while MPC is used to control output AC load voltage under abrupt load changes. Unlike traditional controllers, MPC does not require PI controllers for inner current and outer voltage loop or complex modulation steps. The discrete state-space model of VSI, LC filter, and load currents are used to predict future trends of load voltage for each of eight switching states. The control strategy selects the optimal switching state that reduces the error difference between reference and predicted load voltage. The proposed scheme is tested under perturbation of generation and load parameters. The proposed MPC strategy is compared with the conventional method-based PI controllers. The presented results ensure the effectiveness of the proposed approach with 0.67% THD for the AC output voltage.

Abstract
Microgrids (MGs) are the important entities of distribution systems and more distributed generations (DGs) need to be considered to achieve maximum benefits under the full potential of MGs. By considering the important role of power converters in MGs, problem formulation with model predictive control (MPC) of reconfigurable converter (VSC) is implemented for AC/DC microgrid. The uncertainties due to the loads and sources (RESs) are investigated. Active front end (AFE) rectifier regulates the DC voltage and power is controlled through direct power MPC (DPMPC) during grid connection. Model predictive voltage control (MPVC) regulates AC load voltage in islanded mode. Furthermore, the transition between grid-connected and standalone is thoroughly investigated. MATLAB/Simulink® software authenticates the model performance evaluation of the suggested scheme for different loads. The proposed scheme shows superior attributes with reduced THD.

Abstract
The voltage source converter (VSC) can be operated in bidirectional operational modes i.e. rectification and inversion, which signifies its reconfigurable characteristics. In inverter mode, it operates in both grid-tied and isolated operation modes. In this paper, a fractional-order sliding mode control (FOSMC) is proposed to drive the voltage source converter under reconfiguration. To realize the power system, in grid-tied mode the effect of voltage sag/swell at the point of common coupling (PCC), battery storage (BS) charging, and high voltage (HV) dc-link voltage are considered. Likewise, in isolated mode the voltage at the PCC, BS discharging, and HV dc-link voltage are considered as well. The Riemann-Liouville (RL) is used to design the proposed sliding surface and exponential reaching law is used to minimize the chattering phenomenon. The stability of the proposed controller is proved using the Lyapunov stability criteria. To validate the performance of the proposed strategy, the real-time simulation is accomplished by using the MATLAB/Simulink environment and results are compared with conventional proportional-integral (PI) control. The simulation results demonstrate the effectiveness of the proposed control in terms of robustness, fast-tracking, and rapid convergence as compared to PI control.

Abstract
Lithium-ion battery is one of the most used energy storage technologies in recent times. Enhancing the life span of the Lithium-ion battery is an issue that has technical and economic contributions. This paper addresses improving the life span of Lithium-ion batteries through the appropriate way of charging in the PV system. A modified control methodology is applied for the DC-DC converter-based charger that implements the maximum power point tracking algorithm with considering the battery-safe charging recommendations. The control methodology has been implemented in Matlab Simulink and effectively verified through the simulation results.

Abstract
This preprint has been withdrawn at the request of the corresponding author due to internal coordination requirements and project data privacy considerations.