Dynamics of the world are changing, and people are preferring low cost and reliable power throughout the day. The addition of renewable energy to the existing system is also one of the ways to provide reliable and cheap electricity. The existing bottle neck in transmission lines, continuous contamination of the environment due to heavy reliance on fossil fuels, and the highly fluctuating cost of fossil fuel are few reasons for the widespread use of renewable energy technology. Energy storage technologies are the need of time and range from low capacity mobile storage batteries to high capacity batteries connected to the intermittent renewable energy sources. Selection of different battery types, each having distinguished characteristics in power and energy, depends on the nature of power required and delivered. This paper presents a detailed review of battery energy storage technologies pertaining to the latest technologies, benefits, sizing considerations, efficiency, cost, and recycling. An in-depth analysis in terms of advantages and limitations between the different types of batteries is discussed and compared. In terms of microgrid application, the economic benefits of battery sizing using optimization and probabilistic methods provide a potential solution during the design stage by taking into account various factors affecting the sizing of the battery such as the degradation rate, reliability, and battery placement. This paper ends with the discussion on the recyclability of these batteries and their impact on the environment.

Rising greenhouse gas emissions stemming from fossil fuel-driven vehicles are causing damage to the environment. To counteract this, one solution is the adoption of electric vehicles (EV) for transportation requirements. In this regard, one category of EVs that requires special attention is light electric vehicle (LEV), mainly because of their wide potential in public transportation—especially in developing countries. To realise widespread adoption of LEVs for this purpose, it is imperative to make their charging systems more robust. Consequently, the subject of LEV charging has gained considerable traction, and numerous research works have been reported on this subject in recent years. Hence, this paper aims to chronicle recent research developments on LEV charging techniques, by placing special attention on DC-DC converter topologies used in both on-board and off-board chargers. This review explores recent LEV charger DC-DC converters in literature by segregating them into isolated and non-isolated topologies. Lastly, this work explores challenges and emerging trends in LEV charging, which can potentially be explored by researchers in the future.

Renewable photovoltaic (PV) energy is a primary contributor to sustainable power generation in microgrids. However, PV grid-tied generators remain functional as long as the grid voltage and the input PV source remain normal. Abnormal conditions like transient grid sags or solar irradiation flickering can make the grid-tied inverter go offline. Simultaneous shut down of PV generators residing in the distribution grid may lead to an overall grid instability or outage. Therefore, PV generators must be equipped with fault-ride-through mechanisms in order to remain connected and operational during faults. This paper presents a PV-inverter with low-voltage-ride-through (LVRT) and low-irradiation (LR) compensation to avoid grid flickers. The single-phase inverter rides through the voltage sags while injecting reactive power into the grid. The proposed control strategy ensures a steady DC-link voltage and remains connected to the grid during AC-side low voltage and DC-side low-irradiation faults. Unlike other PV inverters, the controller maintains the maximum-power-point-tracking (MPPT) in all conditions. LVRT, constant power output, and robust MPPT are the noticeable features of the proposed system. Frequency analysis, simulations, and a laboratory prototype validate the proposed control strategy.

Photovoltaic (PV) sources have recently become one of the most mature technologies. With the increasing penetration level and the integration of a PV system into the grid, the stability and reliability of the power networks have been serious concerns. Thus, grid codes are being released by grid operators for low voltage networks under grid faults. Consequently, the Low Voltage Ride Through (LVRT) capability of the grid connected PV system became the most important issue related to grid codes, i.e., more reactive power is injected into the grid during voltage disturbances. In this paper, a comprehensive review of reactive power control strategies for the three-phase PV system has been analyzed to support the grid during voltage sags by providing LVRT capability. The control techniques have been classified into three main categories: Fixed power factor, constant active power control, and constant reactive power control. The results illustrate that the stability of the system is improved when two control techniques are simultaneously implemented. This paper concludes that further research must be carried on LVRT control techniques for the reactive power injection during unbalanced voltage sags.