The installation of photovoltaic (PV) system for electrical power generation has gained a substantial interest in the power system for clean and green energy. However, having the intermittent characteristics of photovoltaic, its integration with the power system may cause certain uncertainties (voltage fluctuations, harmonics in output waveforms, etc.) leading towards reliability and stability issues. In PV systems, the power electronics play a significant role in energy harvesting and integration of grid-friendly power systems. Therefore, the reliability, efficiency, and cost-effectiveness of power converters are of main concern in the system design and are mainly dependent on the applied control strategy. This review article presents a comprehensive review on the grid-connected PV systems. A wide spectrum of different classifications and configurations of grid-connected inverters is presented. Different multi-level inverter topologies along with the modulation techniques are classified into many types and are elaborated in detail. Moreover, different control reference frames used in inverters are presented. In addition, different control strategies applied to inverters are discussed and a concise summary of the related literature review is presented in tabulated form. Finally, the scope of the research is briefly discussed.

Hybrid AC/DC microgrid architecture is emerging as an interesting and attractive approach since it combines the prominent benefits of both AC and DC networks. In Hybrid Microgrids (HMGs), AC and DC networks are interconnected with each other through power converters. Therefore, power converters play a very important role in HMG operation, as their functionality is not only limited to interconnection but also provides power flow control and improves the power quality through different ancillary services. Moreover, due to intermittency of Renewable Energy Resources (RESs), synchronization, load variation, availability of both AC and DC networks, etc., the controllability of the power converters, power management, and protection become very complex in HMG. This paper initially provides a comprehensive review of different interconnection methods and then presents an overview of different control strategies for HMG and Inter-Linking Converters (ILCs). Moreover, power management in different operating modes, including mode transition, is discussed in detail. This paper also provides a critical assessment of the available protection challenges of HMG. Finally, a comprehensive review of different available protection schemes and devices is provided.

To efficiently and accurately track the Global Maximum Power Point (GMPP) of the PV system under Varying Environmental Conditions (VECs), numerous hybrid Maximum Power Point Tracking (MPPT) techniques were developed. In this research work, different hybrid MPPT techniques are categorized into three types: a combination of conventional algorithms, a combination of soft computing algorithms, and a combination of conventional and soft computing algorithms are discussed in detail. Particularly, about 90 hybrid MPPT techniques are presented, and their key specifications, such as accuracy, speed, cost, complexity, etc., are summarized. Along with these specifications, numerous other parameters, such as the PV panel’s location, season, tilt, orientation, etc., are also discussed, which makes its selection easier according to the requirements. This research work is organized in such a manner that it provides a valuable path for energy engineers and researchers to select an appropriate MPPT technique based on the projects’ limitations and objectives.

In this research work, a Maximum Power Point Tracking (MPPT) algorithm is proposed that improves the tracking accuracy and efficiency of the conventional Perturb and Observe (P&O) algorithm. Due to steady-state oscillations and passive dynamics, the efficiency of conventional P&O algorithm is significantly affected in varying climatic conditions. Therefore, to improve its efficiency and tracking accuracy, a reference voltage is defined as a function of irradiance and temperature in the proposed Improved Perturb and Observe (IP&O) algorithm. Moreover, the solar irradiance and temperature of the PV panel are estimated that results in low steady-state oscillations and fast dynamic response. Furthermore, to step-up a low generated PV voltage to a high voltage level, a non-isolated DC–DC converter suitable for large voltage conversion ratios is also designed. The proposed converter uses only one switch that makes its circuitry and control simple and makes it very feasible for PV applications. This converter attains a high voltage gain with relatively low voltage stress on a switch compared with the conventional or other newly developed topologies that have the same or lesser components count. To validate the theoretical concepts of the DC–DC converter and the IP&O algorithm, simulations are carried out in MATLAB/Simulink environment at varying operating climatic conditions. The simulation results and the comparative examination with the conventional P&O algorithm validate the proposed algorithm's adequate performance.

In this work, a non-isolated DC–DC converter is presented that combines a voltage doubler circuit and switch inductor cell with the single ended primary inductor converter to achieve a high voltage gain at a low duty cycle and with reduced component count. The converter utilizes a single switch that makes its control very simple. The voltage stress across the semiconductor components is less than the output voltage, which makes it possible to use the diodes with reduced voltage rating and a switch with low turn-on resistance. In particular, performance principle of the proposed converter along with the steady state analysis such as voltage gain, voltage stress on semiconductor components, and design of inductors and capacitors, etc., are carried out and discussed in detail. Moreover, to regulate a constant voltage at a DC-link capacitor, back propagation algorithm-based adaptive control schemes are designed. These adaptive schemes enhance the system performance by dynamically updating the control law parameters in case of PV intermittency. Furthermore, a proportional resonant controller based on Naslin polynomial method is designed for the current control loop. The method describes a systematic procedure to calculate proportional gain, resonant gain, and all the coefficients for the resonant path. Finally, the proposed system is simulated in MATLAB and Simulink software to validate the analytical and theoretical concepts along with the efficacy of the proposed model.

To guarantee an uninterruptable power supply, a microgrid must be able to operate in both islanded and grid‐connected modes. Hence, it is required to synchronize the voltage phasor of the point of common coupling of the microgrid with the utility grid. Therefore, a distributed cooperative hierarchal control structure is proposed that seamlessly synchronized an islanded microgrid with the utility grid. A proposed method uses a leader‐follower based consensus to regulate the voltage phasor while ensuring proportionate load sharing. A synchronization controller is designed that uses an adjustable parameter to eliminate the voltage magnitude and phase mismatch, and transmit the regulated compensation signal to the leader DGs. The leader DGs transmits these signals to the follower DGs through a cyber‐channels. Moreover, a Massachusetts Institute of Technology rule and Lyapunov function based adaptive controllers are designed to update the secondary control law parameters in case of any disturbance or uncertainty. These adaptive techniques do not require prior knowledge about the microgrid topology, loads, and impedances thus enhancing the system performance. Furthermore, a small signal stability analysis is presented to facilitate the controller parameter design criteria. Finally, the robustness and effectiveness of proposed structure is verified through simulation results in different scenarios.