Stand-alone Wind Energy System Research Articles

Optimal design of hydrogen-based storage with a hybrid renewable energy system considering economic and environmental uncertainties

Hydrogen and electricity derived from renewable sources present feasible alternative energy options for the decarbonisation of the transportation and power sectors. This study presents the utilisation of hydrogen generated from solar and wind energy resources as a clean fuel for mobility and backup storage for stationary applications under economic and environmental uncertainties. This is achieved by developing a detailed techno-economic model of an integrated system consisting of a hydrogen refuelling station and an electric power generation system using Mixed Integer Quadratic Constrained Programming (MIQCP), which is further relaxed to Mixed Integer Linear Programming (MILP). The model is implemented in the Advanced Interactive Multidimensional Modelling Software (AIMMS) and considering the inherent uncertainties in the wind resource, solar resource, costs and discount rate, the total cost of the three configurations (Hybrid PV-Wind, Standalone PV, and Standalone wind energy system) was minimised using robust optimisation technique, and the corresponding optimal sizes of the components, levelised cost of energy (LCOE), excess energy, greenhouse emission avoided, and carbon tax were evaluated. The levelised cost of the deterministic optimisation solution for all the configuration ranges between 0.0702 $/kWh to 0.0786 $/kWh, while the levelised cost of the robust optimisation solution ranges between 0.07188 $/kWh to 0.1125 $/kWh. The proposed integration has the advantages of affordable hydrogen and electricity prices, minimisation of carbon emissions and grid export of excess energy.

Robust finite-time integral terminal sliding mode control design for maximum power extraction of PMSG-based standalone wind energy system

This paper introduces a novel control strategy called Finite-time Integral Terminal Sliding Mode Control (FITSMC), explicitly designed for a permanent-magnet synchronous generator (PMSG)-based standalone Wind Energy Conversion System (WECS). The primary objective of the FITSMC strategy is to regulate the operation of the wind turbine efficiently and maximize power extraction from the WECS. To achieve this, the system is driven onto a sliding surface within a predefined terminal time, ensuring rapid convergence and overall stability. An important advantage of the FITSMC strategy is its ability to maintain a standalone wind power system close to the maximum power point, even under varying wind conditions and load changes. In addition, the controller demonstrates robustness against uncertainties and disturbances, making it highly suitable for real-world applications. Extensive simulations and analyses have been conducted to validate the effectiveness of the proposed FITSMC. The results show a superior control performance compared to traditional methods. Consequently, the FITSMC strategy represents a promising advancement in control techniques for standalone wind power systems, providing an efficient and reliable approach for harnessing power from wind energy.

Comparative Study and Dynamic Performance Analysis of DFIG based Wind Energy Conversion System

This paper presents a novel control strategy for wind energy conversion system for improving the dynamic stability of the system. In off-grid applications, the load voltage and frequency should be managed in steady-state and transient circumstances. For rural areas with unpredictable wind and load circumstances, electricity quality and control are crucial tasks. In order to improve power quality, dynamic stability and power management in direct drive standalone wind energy systems, this research provides a coordinated proportional resonant (PR) controller. Under different operating situations, such as variable wind with step increases and decreases in wind velocity, balanced and unbalanced load conditions, the dynamic performance of a doubly-fed induction generator (DFIG) is evaluated. In order to meet the load requirement, the suggested PR control technique with battery energy controller also provides efficient power balancing between the wind and battery sources. A fair performance comparison is made between the proposed control strategy and conventional vector control strategy by using the MATLAB/SIMULINK platform under varying wind and load circumstances. The proposed control approach shown better dynamic stability, improving the power quality of the system and better synchronization.

A Hybrid Solar Photovoltaic and Wind Turbine Power Generation for Stand-Alone System with IoT-Based Monitoring and MPPT Control

The goal of this effort is to monitor and manage a hybrid stand-alone photovoltaic (PV) and wind energy system (WES) using the Internet of Things (IoT). The suggested hybrid system uses Incremental Conductance (INC) Maximum Power Point Tracking (MPPT) and Perturb and Observe (P&O)-based Sliding Mode Control (SMC) approaches. The cost-effective Arduino Uno board in Matlab is used to analyze the P&O and INC MPPT methods. Energy from renewable sources is stored in a battery, and the output voltage of each source is monitored using the blynk app and GSM 800c module. Simulation results validate the controller’s operation, and the performance of both MPPT algorithms is compared. Experimental outcomes demonstrate the effectiveness of the IoT-based controller and its characteristic functionalities. Overall, this proposed hybrid PV and WES configuration offers advantages such as reduced human resources, cost-effectiveness, time savings, enhanced reliability, and improved data collection and control capabilities.

An Integrated Production/Maintenance Optimization Planning of a Stand-alone Wind Energy System for Rural Electrification

The renewable energy industry has gained so much attention due to the global importance attached to it. However, these sources are volatile in nature, hence, it is important to properly plan the production system to ensure continuity. This work focused on production and maintenance of wind energy system as a stand-alone system for rural electrification. The methodology for power production forecast in this work is optimization using machine learning technique; support vector regression (SVR) and estimation from theoretical technique. The production optimization is aimed to determine the optimal number of panels and batteries required to satisfy the random demand at minimal cost. In order to improve the system functionality and minimize failure, an integrated preventive maintenance model was developed to determine the optimal number of maintenances to be performed. Thus, scheduling optimal time to perform the preventive maintenance. The maintenance model is integrated with the power production rate to determine the maintenance cost. A numerical simulation was presented in order to test the developed algorithm using a case study in Katsina, Nigeria.

Wind energy management of a standalone system operating at maximum power point

In this paper, the management and control of a standalone wind energy system versus variations of wind speed and load are investigated. The system includes a wind turbine coupled to a variable-speed permanent magnet synchronous generator (PMSG), rectifier, boost converter, power inverter, and an energy storage system (ESS). The ESS is a very important part to achieve system stability and support the maximum power point tracking (MPPT) operation. A simple off-line MPPT algorithm is introduced that can be accomplished using the boost converter. The system dynamic model is derived then the control and energy management algorithms are introduced to improve the system performance. The MATLAB platform has been utilized to simulate the proposed system under different disturbances in the load power and wind speed. The results show perfect management of the system energy, good performance of the DC link voltage, stable load voltage, and load frequency.

Super twisting sliding mode approach applied to voltage orientated control of a stand-alone induction generator

To enhance the robustness and dynamic performance of a self-excited induction generator (SEIG) used in a stand-alone wind energy system (WES), a virtual flux oriented control (VFOC) based on nonlinear super-twisting sliding mode control (STSMC) is adopted. STSMC is used to replace the conventional proportional-integral-Fuzzy Logic Controller (PI-FLC) of the inner current control loops. The combination of the proposed control strategy with space vector modulation (SVM) applied to a PWM rectifier brings many advantages such as reduction in harmonics, and precise and rapid tracking of the references. The performance of the proposed control technique (STSMC-VFOC-SVM) is verified through simulations and compared with the traditional technique (PI-FLC-VFOC-SVM). It shows that the proposed method improves the dynamics of the system with reduced current harmonics. In addition, the use of a virtual flux estimator instead of a phase-locked loop (PLL) eliminates the line voltage sensors and thus increases the reliability of the system.

Experimental Investigation of a Standalone Wind Energy System with a Battery-Assisted Quasi-Z-Source Inverter

This paper presents a wind energy conversion system (WECS) for grid-isolated areas. The system includes a squirrel-cage induction generator (SCIG) and a battery-assisted quasi-Z source inverter (qZSI). The batteries ensure reliable and stable operation of the WECS in spite of the wind power oscillations. The maximum power is captured from both the wind turbine (WT) and the SCIG through adjustment of the WT speed and the SCIG operating flux, respectively. The utilized maximum power point tracking (MPPT) algorithms belong to the group of fuzzy logic (FL) search-based algorithms. The battery state of charge (SOC) is tracked online and controlled. When it reaches the minimum allowed level, the load is automatically disconnected; conversely, when it reaches the maximum allowed level, the battery charging is stopped via WT speed control. The load voltage root-mean-square (RMS) value and frequency are at all times controlled at grid-level values. The performance of the proposed system was experimentally validated, in steady state and during transients, achieving wide ranges of wind speed, load power, SOC, and alternating current/direct current (AC/DC) voltage levels. The system startup and low-wind operation were also analyzed. The control algorithms were executed in real time by means of the DS1103 and MicroLabBox controller boards (dSpace).

A Proposed Strategy to Solve the ‎Intermittency Problem in Renewable Energy Systems ‎Using A Hybrid Energy ‎Storage System

Renewable energy resources are a favorable solution for the coming energy. So, a great interest has been paid in the last decades for developing and utilizing renewable energy resources as wind energy. As it has a large energy contents and, particularize with the availability, but the major problems of it are represented in unmatched with load demand because the intermittency and fluctuation of nature conditions. Many studies focused on the new strategy of using Battery Storage System (BSS), and solving some problems that affect the DC bus voltage and the BSS by using Electrochemical Double Layer Capacitor (EDLC). Their capability is to store energy to realize the objective of time shifting of surplus energy with a high efficiency. The article main objective is to model, simulate, design, and study the performance of a Stand-Alone Wind Energy System with Hybrid Energy Storage (SAWS-HES). Thus, a complete model of the proposed system is implemented including a detailed modeling procedure of the HESS components. In addition to the main contribution, a study of the performance of EDLC only as a storage device that has fast response device integrated to the suggested system then it hybridized with the BSS. The HESS has the capability to compensate the DC bus voltage in the transient conditions and gives good stability for the system. The SAWS-HES utilizes one main renewable energy resource as wind turbine and overall model is employed under MATLAB/Simulink including a developed simple logic controller. The SAWS-HES simulation results presented a promising performance and have a satisfied performance in meeting the end load demands at different operation conditions. This ensures the SAWS-HES reliability and the effectiveness with HES and the controller in stand-alone operation formulating an excellent solution for the renewable energy systems

Torque Ripple Reduction in PMSG for Standalone Wind Energy System Using Three Level DTC with A Dither Signal

In this paper, focused on direct torque control (DTC) for permanent magnet synchronous generator direct driven standalone variable speed wind turbine. The machine side converter (MSC) employed three-level DTC with dither signal strategy proposed for minimizes the torque & flux ripple. The triangular signal used as a dither signal & injected in a hysteresis band controller of torque & flux comparator. The optimum magnitude of the triangular wave is 3% of its rated torque & flux used in order to reduce acoustic noise. The proposed strategy minimizes torque & flux ripple as compared to conventional two-level DTC technique. Three-level SVPWM strategy employed for a load-side converter (LSC) in order to reduce harmonic distortion.

Performance enhancement of a stand-alone induction generator-based wind energy system using neural network controller

ABSTRACTThe limitation of self-excited induction generator (SEIG) when used in the stand-alone wind energy system (WES) is poor voltage regulation at variable speed. The indirect vector control (IVC) technique is employed for both the generator-side converter (GSC) and load-side converter (LSC) to regulate the variation of SEIG speed, DC link voltage, and electromagnetic torque independently. Further performance of the proposed IVC technique has been analyzed independently with neural network controller (NNC) and fuzzy logic controller (FLC) as its components. The FLC is replaced by an NNC to improve the performance of the proposed system. IVC of SEIG-based WES has been simulated in MATLAB/SIMULINK software, and the prototype model of the proposed WES is developed to experimentally validate the performance using dSPACE DS-1104 R&D controller board.

Load Current Observer and Adaptive Voltage Controller for Standalone Wind Energy System with Linear and Non-linear Loads

The Wind Energy Conversion System (WECS) is one of the most important renewable energy systems in the existing power network, which can be operated in either grid connected or standalone mode. In the standalone WECS, voltage and frequency variations are more due to the wind speed variations, load changes and switching surges. In this paper, space vector pulse width modulation based adaptive voltage controller with load current observer is used to control the voltage and frequency, for the standalone or isolated WECS. The isolated system is simulated using MATLAB/Simulink and the results are analysed when three-phase non-linear and linear (Resistive and Inductive) balanced and unbalanced loads are connected.

Load Analysis of Statcom with Voltage Regulation Controller Based Standalone Wind Energy System

The actual values of the output voltages of the wind turbine have been observed, where the wind speed varies between 0 and 25 m / s. It is designed to handle heavy loads and the voltage drop is controlled and compared to the system using the STATCOM voltage regulator with AC DC. The load has been permanently modified to determine the optimal load value for which both systems are compatible. The waveform of the open circuit voltage output varies from 800 to 1000 volts. This voltage must be maintained when a load must be transported without loss of value. It has been observed that the voltage drop in the system without STATCOM is above 1000 KW and a load of 500 KW. However, the optimal value of the system until the load can work is 18 kW and STATCOM has a controller for CC regulation. The value has been improved to 50 kW.

Gain Scheduling Proportional Integral for Standalone Wind Energy System

The isolated location in developing countries like India where grid is not readily accessible, the standalone system with renewable or with conventional source is inevitable. Due to the ample availability of solar and wind energy, they are the most suitable and affordable energy sources in the standalone mode. The fixed gain proportional integral controller is usually obtained in such system. These controllers are tuned for specific conditions to obtain the voltage regulation, so optimal tuning of these controller is necessary to acquire desired operation of the overall system. This can be done by scheduling the gain dynamically. This paper focuses on the incorporation of gain scheduling proportional integral controller applied to the standalone wind energy conversion system with change in wind speed conditions. The real data for the wind speeds are taken for the location of Ahmedabad, Gujarat, India to check the performance of wind energy system connected with DC load and analysis is done at average wind speed.

Design of Optimal Hybrid Renewable Energy System for Sustainable Power Supply to Isolated-grid Communities in North Central, Nigeria

The study analyzed the feasibility and techno-economic viability of renewable electricity generation from wind and solar standalone systems, and as hybrid facilities in six states across North-central, Nigeria. 24 years’ daily solar and wind data were sourced from the Nigeria Meteorological Department, Oshodi. The dataset was analyzed and employed to design an alternative RE power supply system as a test case for university communities with an equivalent consumption of 28.9 MWh/day. The electricity load demand adopted was based on an audit of electricity generation conducted for the University of Lagos main campus. The supply architecture adopted in this study excludes the use of heavy equipment or machinery loads and only caters for the institutions’ base loads. An evaluation of the design that will optimally match the daily load demand of the communities with LOLP ranging from 1 to 50% was undertaken. HOMER software was employed as the optimisation tool together with other statistical and analytical variations to determine best design for the sites with diesel standalone facility taken as the base system. The outcome showed that hybrid generation system fared better than the standalone PV or Wind energy system at Abuja, Ilorin, Lokoja and Makurdi, while the wind standalone system was the optimal generation technology at Minna and Jos. Further to this, values of the levelized cost of energy showed that adopting wind resources (as standalone or in hybrid format with PV) for power generation at the sites/institutions at Minna and Jos, is more viable than the use of diesel generators.

A Four-port DC-DC Converter for a Standalone Wind and Solar Energy System

This article proposes an integrated, four-port, dc–dc converter for power management of a hybrid wind and solar energy system when it works in the standalone mode. Compared with existing four-port dc–dc converters, the proposed converter has the advantage of using a simple topology to interface sources of different voltage/current characteristics. The proposed converter is constructed for power management of a hybrid energy system, which consists of a photovoltaic panel, a wind turbine generator, a rechargeable battery bank, and a load. The simulation and experimental results show that the proposed converter is capable of not only controlling the charge and discharge of the battery according to the state of the charge, but also maintaining the dc-link voltage to be constant.

Sizing a stand-alone solar-wind-hydrogen energy system using weather forecasting and a hybrid search optimization algorithm

Due to increasing energy demand and fossil fuel costs in island and remote areas, renewable energy resources are becoming increasingly attractive. The hybridization of these resources can help overcome their variability and intermittency and improve efficiency. Many independent hybrid renewable energy systems are used in remote and island areas for which weather data often is unavailable. To increase the accuracy of size optimization of such systems, more accurate weather data is needed and the use of weather forecasting data is helpful. In this article, a new hybrid optimization algorithm is proposed for the optimal sizing of a stand-alone hybrid solar and wind energy system based on three algorithms: chaotic search, harmony search and simulated annealing. To improve the accuracy of the size optimization algorithm results, weather forecasting is used along with artificial neural networks for solar radiation, ambient temperature, and wind speed forecasting. The main objective function of minimizing the total life cycle cost is used to assess the feasibility of the hybrid renewable energy system accounting for system reliability. The reliability of the system is assessed by the loss of power supply probability parameter. The new method is tested for the electrical load of the city of Khorasan, Iran. The results are compared with those obtained by the proposed algorithm (harmony search and simulated annealing-based artificial neural networks). The simulation results demonstrate the advantages of utilizing the hybrid optimization algorithm with weather forecasting data for a stand-alone hybrid renewable energy system.

Techno-Economic Analysis of a Stand-Alone Hybrid Wind Energy System with Fuel Cell Case Study: Kouhin Region in Qazvin

Techno-Economic Analysis of a Stand-Alone Hybrid Wind Energy System with Fuel Cell Case Study: Kouhin Region in Qazvin

Dynamic performance improvement of standalone battery integrated PMSG wind energy system using proportional resonant controller

The load voltage and frequency should be controlled under steady state and transient conditions in off grid applications. Power quality and power management is very important task for rural communities under erratic wind and load conditions. This paper presents a coordinated Proportional resonant (PR) and battery energy controller for enhancement of power quality and power management in direct drive standalone wind energy system. The dynamic performance of standalone direct drive Permanent Magnet Synchronous Generator (PMSG) is investigated with the proposed control scheme under various operating conditions such as fluctuating wind with step increase and decrease in wind velocity, balanced and unbalanced load conditions. The proposed PR control strategy with battery energy controller also ensures effective power balance between wind and battery source in order to fulfill the load demand. The superiority of the proposed control strategy is confirmed by comparing with the traditional vector control strategy under fluctuating wind and load conditions through MATLAB/SIMULINK platform.

A Novel Method for Fast Configuration of Energy Storage Capacity in Stand-Alone and Grid-Connected Wind Energy Systems

In this paper, a novel method is proposed and applied to quickly calculate the capacity of energy storage for stand-alone and grid-connected wind energy systems, according to the discrete Fourier transform theory. Based on practical wind resource data and power data, which are derived from the American Wind Energy Technology Center and HOMER software separately, the energy storage capacity of a stand-alone wind energy system is investigated and calculated. Moreover, by applying the practical wind power data from a wind farm in Fujian Province, the energy storage capacity for a grid-connected wind system is discussed in this paper. This method can also be applied to determine the storage capacity of a stand-alone solar energy system with practical photovoltaic power data.