This paper deals with a comprehensive study of configurations of microgrid (MG) based on variable speed generators. The selection criteria for these configurations along with the design of required control algorithms, are presented in detail. Simulation results and experimental validation of selected MG configurations are given to demonstrate their suitability. It is aimed to enhance applications of MGs with main emphasis on renewable energy sources to ensure sustainable development in rural and remote areas.

In this paper, the design and implementation of active power control with antiwindup PI controller (AWPI) and improved perturbation and observation (P&O) method with sliding mode control (SMC), are investigated to get a high level of performance with a reduced number of sensors for a stable operation of a wind-PV-battery-based hybrid standalone power generation system (HSPGS). The SMC approach with boundary layer is used for an optimum trajectory on the sliding surfaces, with variable operating conditions of many power converters connected at the same DC bus. Furthermore, detailed modeling and stability analysis to demonstrate the transversality, reachability, and equivalent control are presented. The effectiveness and robustness of HSPGSs and their respective control strategies are validated by simulation and test results on a hardware prototype using a DSP-dSPACE real time controller.

In this paper, a comprehensive controller of a standalone microgrid is implemented, which has three dispersed generation units based on a wind, solar photovoltaic (PV) array, and a diesel generator (DG). The power ratio variable step perturb and observe method is applied to achieve maximum power point tracking of a solar PV array and a variable speed wind turbine coupled a permanent magnet brushless dc generator without rotor/wind speed sensors. Moreover, to ensure perfect synchronization of a DG to the point of common coupling (PCC), a control algorithm is developed, which is based on in-phase and quadrature units. An active power control based on proportional–integral controller with anti-windup, is used for voltage and frequency regulation. The LCL filter based on virtual resistor, is used for power quality improvement at PCC. Simulation and test results are presented for the validation of the proposed system using a prototype of 2 kW in the laboratory.

In this paper a new active power control (APC) with enhanced maximum power point tracking (MPPT) algorithm are implemented to improve the performances of a solar photovoltaic system (SPV) based standalone water pumping station. The APC uses proportional resonant controller with anti-windup (AWPRC) for AC voltage regulation without saturation phenomena and with high power quality at the point of common coupling (PCC). Furthermore, PRC design method for optimal gains to achieve high performance during transition period in term of phase margin and desired settling time is analyzed. To achieve MPPT with less oscillation while protecting the battery energy storage system (BESS) from overvoltage, an enhanced power ratio variable step based perturbation and observation (P&O) algorithm is used. The effectiveness of the developed control strategies are validated through simulations and experimental results.

Diesel generators (DGs) are set to work as a backup during power outages or support the load in remote areas not connected to the national grid. These DGs are working at a constant speed to produce reliable AC power, while electrical energy demand fluctuates according to instantaneous needs. High electric loads occur only for a few hours a day in remote areas, resulting in oversizing DGs. During a low load operation, DGs face poor fuel efficiency and condensation of fuel residues on the walls of engine cylinders that increase friction and premature wear. One solution to increase combustion efficiency at low electric loads is to reduce diesel engine (DE) speed to its ideal regime according to the mechanical torque required by the electrical generator. Therefore, Variable Speed Diesel Generators (VSDGs) allow the operation of the diesel engine at an optimal speed according to the electrical load but require additional electrical equipment and control to maintain the power output to electrical standards. Variable speed technology has shown a significant reduction of up to 40% fuel consumption, resulting in low GHG emissions and operating costs compared to a conventional diesel generator. This technology also eliminates engine idle time during a low load regime to have a longer engine lifetime. The main objective of this survey paper is to present the state of the art of the VSDG technologies and compare their performance in terms of fuel savings, increased engine lifetime, and reduced greenhouse gases (GHG) emissions. Various concepts and the latest VSDG technologies have been evaluated in this paper based on their performance appraisal and degree of innovation.

In the context of electricity production in remote areas, the use of diesel generators, either alone or in hybridization with renewable energy sources, faces many technical problems. Indeed, the electrical instability that often characterizes the isolated networks, due to the fluctuating character of renewable resources and the high variability in the load profile, leads to the operation of the diesel generator in transient dynamic conditions, at low loads or outside prescribed environmental conditions. Furthermore, the extended operation of the diesel generator at low charge results in the condensation of combustion residues on the engine cylinder walls, which, after a certain time, increases friction, reduces the efficiency and increases fuel consumption. One way to solve this problem and to eliminate these deposits is to operate the engine at a higher speed until the operating temperature is reached. This paper explores the impact of the wind turbine penetration rate for hybrid wind–diesel systems and the effects of cold temperatures, high altitude, and other environmental operation conditions on diesel generators’ performances. We outlines the impacts of low load and environmental conditions such as ambient temperature, humidity, moisture, abrasive dust, cold and corrosive environments on the operation of modern diesel generators. The problem has been approached by examining the existing literature, researching damage cases, analyzing existing data, and assessing industrial experiences.