Small-scale Wind Power Generation Research Articles

Assessment of Wind Resource and Its Energy Potential in Three States of Northwest Nigeria

The growing need for clean energy to address the environmental issues caused by the usage of fossil fuels results to the need for Nigeria to develop an alternative energy from untapped wind which is in abundance in the region. The aim of this study is to evaluate wind power potential and wind energy resources of three locations (Kaduna, Kano and Katsina) of northwestern part of Nigeria. The Nigerian Meteorological agency (NIMET) provided the wind speed data spanning 25 years (1996-2020). In the analysis, Weibull two-parameter statistical model was used. The distribution of wind speed across Nigeria demonstrates that some areas in the North are equipped to generate wind. Microsoft excel was used in analyzing the wind speed data obtained. In addition, evaluation of the region’s wind energy resources shows that Kano recorded the highest potential, with WPD of 443.03 Wm-2 at 10m AGL with annual WED of 4.921 kWhm-2day-1 while Kaduna recorded the lowest potential of 198.43 Wm-2 with annual WED of 2.093 kWhm-2day-1. As a result, Kaduna is found to be ideal for small scale wind power generation, while Kano and Katsina may be suitable for large scale wind power generation.

Enhancing Savonius Vertical Axis Wind Turbine Performance: A Comprehensive Approach with Numerical Analysis and Experimental Investigations

Small-scale vertical-axis wind power generation technologies such as Savonius wind turbines are gaining popularity in suburban and urban settings. Although vertical-axis wind turbines (VAWTs) may not be as efficient as their horizontal-axis counterparts, they often present better opportunities for integration within building structures. The main issue stems from the suboptimal aerodynamic design of Savonius turbine blades, resulting in lower efficiency and power output. To address this, modern turbine designs focus on optimizing various geometric aspects of the turbine to improve aerodynamic performance, efficiency, and overall effectiveness. This study developed a unique optimization method, incorporating a new blade geometry with guide gap flow for Savonius wind turbine blade design. The aerodynamic characteristics of the Savonius wind turbine blade were extensively analyzed using 3D ANSYS CFX software. The optimization process emphasized the power coefficient as the objective function while considering blade profiles, overlap ratio, and blade number as crucial design parameters. This objective was accomplished using the design of experiments (DOE) method with the Minitab statistical software. The research findings revealed that the novel turbine design “OR0.109BS2BN2” outperformed the reference turbine with a 22.8% higher power coefficient. Furthermore, the results indicated a trade-off between the flow (swirling flow) through the gap guide flow and the impact blockage ratio, which resulted from the reduced channel width caused by the extended blade tip length.

A Study on a Casing Consisting of Three Flow Deflectors for Performance Improvement of Cross-Flow Wind Turbine

We investigated the effective use of cross-flow wind turbines for small-scale wind power generation to increase the output power by using a casing, which is a kind of wind-collecting device, composed of three flow deflector plates having the shape of a circular-arc airfoil. Drag-type vertical-axis wind turbines have an undesirable part of about half of the swept area where the inflow of wind results in low output performance. To solve this problem, we devised a casing consisting of three flow deflector plates, two of which were to block the unwanted inflow of wind and the remaining flow deflector plate having an angle of attack with respect to the wind direction to increase the flow toward the rotor. In this study, output performance experiments using a wind tunnel and numerical fluid analysis were conducted on a cross-flow wind turbine with three flow deflector plates to evaluate the effectiveness of the casing on output performance improvement. As a result, it was confirmed that the casing could improve the output performance of the cross-flow wind turbine by approximately 60% at the maximum performance point and could also maintain the output performance about 50% higher compared to the bare cross-flow wind turbine without the casing within a deviation angle of ±10 degrees, even when the casing direction was inclined against the wind direction due to changes in wind direction.

Geo-Statistical Estimation and Temporal Distribution of Wind Speed Data of Karachi Airport

Karachi city is a coastal city near the Arabian sea. Due to its location, wind speed may provide a sustainable small scale wind energy system as well as reduction in power shortage in the city. In this study, wind speed data of Karachi Airport station at 10m height is used to estimate wind speed in the surrounding area with reference to measured wind speed data of the station. This estimated wind speed will then be helpful to assess small scale wind power generation at the unsampled locations. Geo-Statics tool in ArcGIS version 10.1 software was utilised to estimate measured wind speed using different interpolation methods. Descriptive statistics were used to analyse and compare measured and estimated wind speed. The analysis summarises the effectiveness of the estimated wind speed. Time series variations of the wind speed data was also analysed. Temporal mapping showing seasonal variations of the wind speed. The descriptive statistics illustrated a high value of correlation coefficient ‘r’, coefficient of determination R2 which is 99.8% for Ordinary and Universal kriging interpolation methods, while it was calculated 99.6% for Simple kriging. A slightly higher coefficient of variation resulted in Ordinary and Universal kriging methods than the Simple kriging method. The results indicated that all three kriging methods performed better and are more effective to estimate wind speed and wind power in the surrounding area and for Temporal display.

Research on Green Transformation of Campus Sponge and Energy Saving Facilities on Sloping Land

Based on the renovation of sponge and energy-saving facilities in a middle school in Nanning, this paper systematically studies the overall elevation of the campus, the composition of the drainage system and the layout of space functions, and formulates a characteristic scheme for the renovation of sponge and energy-saving facilities according to the characteristics of the sloping campus. In order to control the total amount of rainwater runoff, the sponge transformation mainly adopts the transformation methods of partition catchment, upper storage and lower use, multi-stage detection and classification treatment. For the purpose of solar energy and wind energy utilization, solar photovoltaic panels and small-scale wind power generation system are adopted. The application effects of sponge and energy-saving facilities are estimated and evaluated.

Control for Power Converter of Small-Scale Switched Reluctance Wind Power Generator

With the rapid development of wind power generation technology worldwide, the influence of intermittent and fluctuating characteristics of wind power generation on the microgrid and load is attracting a lot of attention along with its increasing penetration. Aimed at solving the problem that only wind speed variation is considered in the generation plan of traditional small-scale wind power generation applications, this article presents a set of control schemes for the switched-reluctance-generator-based small-scale wind power generation system with the integrated energy storage system. Considering the possibility of off-grid operation of small-scale wind power generation systems in the areas where the grid is weak or even uncovered, the proposed control scheme increases the consideration of dynamic changes in load and energy storage unit. To improve the utilization efficiency of small-scale wind power generation, a step control scheme is proposed combining maximum power tracking control with power balance control. The two-stage inverter is established to generate ac 110V/60Hz outputs by voltage closed-loop control in boost circuit of front stage and proportional integral (PI) control in the inverter circuit of the second stage. Finally, the effectiveness of the proposed control schemes is verified experimentally.

Design and Simulation of Permanent Magnet Synchronous Generators for Small Scale Wind Power Plants

Wind energy is one of the primary energy sources that can be used to produce electricity. Indonesia has the potential to harness wind energy to produce electricity due to located on the equator, especially in coastal areas. An alternative to the availability of electricity in remote coastal areas is to use small-scale wind power plants. One component that plays an important role in wind power generation systems is the generator. A generator is a machine that converts mechanical energy into electrical energy. In small scale wind power plants, permanent magnet synchronous generators (PMSG) are commonly used as energy conversion machines. In this paper, a PMSG has been designed for small-scale and low-speed wind power generation as an energy conversion machine. PMSG which has been designed has the following specifications: 500 W, three phases, 18 slots, 12 poles, with a rotation speed of 500 rpm. The simulation test results obtained the following data, the output phase-phase maximum voltage of the generator is 38.84 V, and phase maximum voltage is 22.5 V.

Electromagnetic Field Characteristic Analysis and Comparison of Slotless Permanent Magnet Synchronous Generators with Grid Connection

This paper deals with the characteristic analysis of permanent magnet (PM) wind power generators according to stator winding topology to compare the machine performance, and the experimentally measured current with grid connection is employed for the investigation. The analysis models dealt with in this study have the slotless structure in their stator core to eliminate the cogging torque with the identical PM rotor, and three coil winding types according to coil pitch and winding types are addressed for their comparison. One of the analysis models is manufactured to be integrated with a grid-connected power converter, and the measured phase current of the generator is applied to investigate their flux density, resulting radial force and power loss characteristics of each analysis model. For the reasonable comparison, the generators have very similar equivalent circuit parameters, such as induced voltage and resistance, so the load voltage and current characteristics are almost identical. From the results dealt with in this study, one of the analysis models is proposed to be applied for the small-scale wind power generation systems.

Assessment of wind energy resources in Nigeria – a case study of north-western region of Nigeria

This study assesses the wind-energyresources in Nigeria by reviewing the existing literature on the subject matter, and also evaluates the wind potential in six locations in the northwest region of the country. Twenty-two years’ (1984 – 2005) wind speed data obtained from the Nigerian Meteorological Agencies (NIMET) were used in this study.Weibull two-parameter and other statistical models were employed in this analysis. Wind speed distribution across Nigeria shows that some locations in the northern part of the country are endowed with higher wind potential than others in the southern part of the country. Moreover, assessment of the wind-energy resources in the study locations reveals that wind energy potential in the region is lowest in Yelwa and highest in Kano; WPD varies from 28.30 Wm-2 to 483.72Wm-2 at 10 m AGL, 45.33 Wm-2 to 775.19 Wm-2 at 30 m AGL and 56.43 Wm-2 to 964.77 Wm-2 at 50 m AGL.Thus Kano, Sokoto and Katsina are suitable for large-scale wind power generation, while Gusau is suitable for small-scale wind power generation; whereas Yelwa and Kaduna may not be suitable for wind power production because of their poor wind potential.

Characteristics of ice accretions on blade of the straight-bladed vertical axis wind turbine rotating at low tip speed ratio

Icing on blade surface of wind turbine greatly affects the performance of wind turbine which becomes a very serious problem for the wind turbine installed in cold and wet regions both for larger-scale wind turbine and small-scale ones. The Straight-bladed Vertical Axis Wind Turbine (SB-VAWT) is a kind of lift-type VAWT which is widely used for small-scale wind power generation. Icing on blade of SB-VAWT will also affect both the starting performance and out power performance. To verify the icing characteristics of blade rotating at low tip speed ratio of the SB-VAWT during its starting stage, wind tunnel icing experiments have been carried out on a rotor with blade airfoil of NACA0018 in a wind tunnel icing experimental system by using natural low temperature in winter proposed in this study. The icing distributions were recorded by a high speed camera at different tip speed ratios from 0 to 1. The weight of icing on blade was also measured. Furthermore, the icing area ratio and icing rate were calculated and analyzed. The main results show that the ice accretion on a rotating blade of SB-VAWT at low tip speed ratio is quite different from the blade in static condition. The icing distributed on the whole surface of blade and the icing area increases along blade airfoil outline with the increasing of icing time and rotational speed. The whole weight of icing on all blades of wind turbine increased with the increasing of blade number.

Multiobjective Optimization Design of Small-Scale Wind Power Generator With Outer Rotor Based on Box–Behnken Design

In this paper, the finite-element method (FEM) based on 2-D numerical analysis was used for the basic design and characteristics analysis of a small-scale 3-kW wind power generator to which a permanent-magnet generator was applied. A prototype was manufactured, and a characteristics experiment was performed to verify the designed generator. In addition, the optimization design in order to satisfy required power of a generator while minimizing the cogging torque and the back electromotive force (EMF) total harmonic distribution (THD) on the basis of the designed initial model generator was conducted using the Box-Behnken design (BBD), which is a response surface method (RSM). The cogging torque, the back EMF THD, and the output power for each level of the design factors selected by the BBD were derived by the FEM based on 2-D numerical analysis. As a result, the optimal design model was derived in consideration of the RSA among each factor and the main effect and the interaction effects of each factor. This demonstrated the validity of the optimized design of the urban small-scale wind power generator design using the BBD.

Sensorless fuzzy‐logic‐based maximum power point tracking control for a small‐scale wind power generation systems with a switched‐mode rectifier

This study proposes a sensorless maximum power point tracking (MPPT) control using an improved variable-speed small-scale wind power generation system (WPGS) with a permanent magnet synchronous generator. The passive elements of a small-scale WPGS that use a conventional boost converter suffer from disadvantages that result in power losses, increased costs, and increased system size. Therefore, to eliminate the passive elements, the proposed system performs MPPT control to vary the duty ratio of a switched-mode rectifier. To evaluate the MPPT algorithms, a comparison was made between a fuzzy-logic-based perturb-and-observe (P&O) control with variable step size and a conventional P&O control with fixed-step size. A wind turbine model is investigated using a squirrel-cage induction motor, and the variable torque is controlled by varying the generator speed. The presented system and algorithm are verified by the simulations and experiments.

Design of disk type PM synchronous generator based on halbach

This paper expounds the application merits of disk type PM synchronous generator in small-scale wind power generation .The characteristics of the disk type PM synchronous generator were analyzed and 8P, 200W disk type generator with 90 degree Halbach magnet structure was designed. Simulation and calculation are carried out by using finite element method. By comparing the 90 degree Halbach magnet structure and the traditional magnet structure of the disk type generator, the results shows that the 90 degree Halbach magnet structure can improve the air gap magnetic density, reduce the leakage of main magnetic circuit and the loss.

Methodologies for city-scale assessment of renewable energy generation potential to inform strategic energy infrastructure investment

In support of national and international policies to address climate change, local government actors across Europe and Asia are committed to reducing greenhouse gas emissions. Many recognise the contribution that decentralised renewable electricity production can bring towards reducing emissions whilst also generating revenue. However, these actors are often subject to significant financial pressures, meaning a reliable and compelling business case is needed to justify upfront investment. This article develops a method for rapid comparison of initial project viability for multiple city sites and installation options using data from wind and solar resource prediction techniques. In doing so, detailed resource assessments grounded in academic research are made accessible and useful for city practitioners.Long term average wind speeds are predicted using a logarithmic vertical wind profile. This employs detailed three-dimensional building data to estimate aerodynamic parameters for the complex urban surface. Solar resource is modelled using a Geographical Information System-based methodology. This establishes the location and geometry of roof structures to estimate insolation, whilst accounting for shading effects from other buildings and terrain features. Project viability for potential installations is assessed in terms of the net present value over the lifespan of the technology and associated Feed-in Tariff incentive. Discounted return on investment is also calculated for all sites. The methodology is demonstrated for a case study of 6794 sites owned by Leeds City Council, UK. Results suggest significant potential for small-scale wind and solar power generation across council assets. A number of sites present a persuasive business case for investment, and in all cases, using the generated electricity on site improves financial viability. This indicates that initial installations should be sited at assets with high electricity demands. Overall, the work establishes a methodology that enables large city-level asset holders to make strategic investment decisions across their entire portfolio, which are based on financial assessment of wind and solar generation potential accurate to the individual asset scale. Such tools could facilitate strategic planning within cities and help to ensure that investment in renewable energy is focused at the most viable sites. In addition, the methodology can assist with asset management at the city scale by identifying sites with a higher market value as a result of their potential for renewable energy generation than otherwise might be estimated.

Wind Power potential in Kigali and Western provinces of Rwanda

Wind speed and wind direction are the most important characteristics for assessing wind energy potential of a location using suitable probability density functions. In this investigation, a hybrid-Weibull probability density function was used to analyze data from Kigali, Gisenyi, and Kamembe stations. Kigali is located in the Eastern side of Rwanda while Gisenyi and Kamembe are to the West. On-site hourly wind speed and wind direction data for the year 2007 were analyzed using Matlab programmes. The annual mean wind speed for Kigali, Gisenyi, and Kamembe sites were determined as 2.36m/s, 2.95m/s and 2.97m/s respectively, while corresponding dominant wind directions for the stations were , and respectively. The annual wind power density of Kigali was found to be while the power densities for Gisenyi and Kamembe were determined as and . It is clear, the investigated regions are dominated by low wind speeds thus are suitable for small-scale wind power generation especially at Kamembe site.

Wind Power Potential in Kigali and Western Provinces of Rwanda

Wind speed and wind direction are the most important characteristics for assessing wind energy potential of a location using suitable probability density functions. In this investigation, a hybrid-Weibull probability density function was used to analyze data from Kigali, Gisenyi, and Kamembe stations. Kigali is located in the Eastern side of Rwanda while Gisenyi and Kamembe are to the West. Onsite hourly wind speed and wind direction data for the year 2007 were analyzed using Matlab programmes. The annual mean wind speed for Kigali, Gisenyi, and Kamembe sites were determined as 2.36m/s, 2.95m/s and 2.97m/s respectively, while corresponding dominant wind directions for the stations were 3200, 1800 and 1500 respectively. The annual wind power density of Kigali was found to be 13.7W/m2, while the power densities for Gisenyi and Kamembe were determined as 18.4W/m2and 24.4W/m2. It is clear, the investigated regions are dominated by low wind speeds thus are suitable for small-scale wind power generation especially at Kamembe site.

계통 연계형 인버터의 DC-Link 전압 가변을 통한 소형 풍력발전 시스템의 MPPT 제어

In this paper, the Maximum Power Point Tracking(MPPT) control of the small scale wind power generation system with a three-phase diode rectifier and the grid-connected inverter is studied. Without the need for the converter circuits to control speed of the generator, it is economical and the structure is simple. Compared with existing systems, it can be to reduce the power semiconductor switches and passive elements, and to implement the MPPT control with only DC-Link voltage control of the grid-connected inverter. In order to allow MPPT control without the characteristic information of the wind turbine, the P&O algorithm is applied, and these are verified by the simulation and experiment.

Design Method for the Automatic MPPT Wind Power Generator System

The maximum power point tracking (MPPT) for the small-scale wind power generator systems is a hot research topic. We presented a novel solution for MPPT in 2013 that eliminates the disadvantages of conventional methods, such as low reliability and high loss. The wind power generator system is able to track maximum power automatically without using converters and control circuits. This paper mainly discusses the design method for this novel generator. A prototype has been designed and manufactured, and simulations and experiments have validated the generator system concept.

Dynamic modeling and performance evaluation of axial flux PMSG based wind turbine system with MPPT control

This research work develops dynamic model of a gearless small scale wind power generation system based on a direct driven single sided outer rotor AFPMSG with coreless armature winding. Dynamic modeling of the AFPMSG based wind turbine requires machine parameters. To this end, a 3D FEM model of the generator is developed and from magnetostatic and transient analysis of the FEM model, machine parameters are calculated and utilized in dynamic modeling of the system. A maximum power point tracking (MPPT)-based FOC control approach is used to obtain maximum power from the variable wind speed. The simulation results show the proper performance of the developed dynamic model of the AFPMSG, control approach and power generation system.

과풍속 영역에서의 약계자 제어를 이용한 풍력발전용 3상 PWM 컨버터의 출력제어

This paper proposes the battery charging algorithm for small-scale wind power generator using three phase PWM converter. it is impossible to control output power of the converter in over wind speed region since back EMF of PMSG is higer than battery voltage. Therefore, battery charging algorithm is proposed to expand battery charging over wind speed region. The suggested method is using the q-axis current for battery charging in the rated wind speed region. In the over wind speed region after it lower back EMF of PMSG using d-axis current it can control output power of the converter. The validity of the proposed algorithm are verified by experiments.