•Good prospects of PV–wind hybrid systems are found in western Himalayan Indian state.•A 6kWp roof mounted PV–micro wind hybrid system at Hamirpur location is studied.•Optimum PV–wind hybrid system ...configurations are determined for 12 locations in the region.•Comparative analysis of hybrid systems is carried out using ANN, NASA and measured data.•Methodology can be used for assessing the potential of hybrid power systems worldwide.
The western Himalayan state of Himachal Pradesh is known as the hydro-power state of India with associated social and environmental problems of large hydro power plants. The reduced water inflow in the rivers during extreme winters affects power generation in the state. Therefore solar and wind resources need to be utilized to supplement power generation requirements. With this objective the prospects of photovoltaic–micro wind based hybrid systems are studied for 12 locations of the state. The NASA data, Artificial Neural Network predicted and ground measured data are used in the analysis of Hamirpur location whereas for remaining 11 locations estimated, NASA and Artificial Neural Network predicted data are used, as measured solar and wind data are not available for most of the locations in the state. Root Mean Square Error between three input data types are found to range from 0.08 to 1.89. The results show that ANN predicted data are close to measured/estimated data. A 6kWp roof mounted photovoltaic–micro wind hybrid system at Hamirpur with daily average energy demand of 5.2kWh/day is studied. This system specifications are used to obtain optimum PV–micro wind based hybrid power system configurations for all locations. The optimum configuration for Hamirpur is found to be a 5kWp micro wind turbine, 2kW converter, 10 batteries and 8kWp PV system whereas for other 11 locations a 5kWp micro wind turbine, 2kW converter, 10 batteries and 2–9kWp PV systems are obtained. The normalized solar and wind energy generation are found to range between 1034–1796kWh/kWp/yr and 222–616.8kWh/kWp/yr respectively for all locations. The study shows that state has good prospect of power generation from hybrid systems with major solar and minor wind components. However, a detailed follow up wind resource assessment programme is needed for the Himalayan region to identify true wind penetration for wind based solar hybrid power systems. The methodology presented can be used for the prediction of the photovoltaic and wind power generation potential for any region worldwide.
An energy harvesting (EH) system is proposed to extract energy from a centimeter-scale electromagnetic (EM) micro wind turbine. To improve the end-to-end efficiency, an autonomous and self-biased ...active rectifier is employed. A hysteresis-controlled boost converter is designed with self-zero-current-switching calibrations, which achieves a peak DC-DC efficiency of 93.3% with a maximum efficiency improvement of 12.7%. In addition, a novel frequency-to-amplitude conversion (FAC) maximum power point tracking (MPPT) method is proposed for a cycle-to-cycle MPPT. In measurements, the proposed FAC MPPT requires no more than three cycles to locate the maximum power point (MPP) in abrupt frequency changes, with an 80% tracking accuracy in the first turbine cycle. In wind-field testing, the EH system starts to track the MPP one cycle after start-up at 2.0 V. In the steady-state, the EH system maintains its cycle-to-cycle MPP under different wind conditions. In wind-field testing for wind speeds from 1.0 to 5.0 m/s, the peak MPPT accuracy is 99.27%, with an MPPT efficiency of 99.85%. The extracted power is from 0.1 to 8 mW with a peak end-to-end efficiency of 88.2%. Compared to a full-bridge rectifier, a 630% energy extraction gain is measured at a low wind speed of 1.2 m/s. To the best of the authors' knowledge, this is the first IC prototype for a cm-scale EM wind turbine EH to achieve a cycle-to-cycle MPPT with the highest reported MPPT efficiency.
In this paper, the performance of micro wind turbine (MWT) is evaluated by taking into account low average wind speed cities in the West Cameroon region such as Bandjoun and Bangangte. The k-ϵ ...turbulence flow model was used to simulate the flow around wind turbine blades by considering five airfoils profiles (A18, BW3, 3R F1B, FX60-100 and K3311) with high performance at low wind speeds for different wind angles of attack (0°, 10°, 20° and 30°). Two-dimensional numerical simulations with COMSOL Multiphysics CFD module were performed and velocity surface and pressure contours were presented. In order to evaluate the forces exerted by the wind onto the airfoils, lift and pressure coefficients, and drag force were also computed to quantify their efficiency and aerodynamic performance. It has been concluded that 3R F1B airfoil has the best performance and is more efficient for the design of MWT blades in these regions.
This paper presents a novel power conditioning unit (PCU) for variable-speed micro wind turbine applications. It contains a simple generator-side rectifier, galvanic isolation with a simple dc-dc ...converter, and a single-phase full-bridge inverter at the grid side. Variable-speed micro wind turbines based on a permanent magnet synchronous generator (PMSG) are increasingly used in residential and small commercial buildings, despite their relatively low output voltage. Therefore, they can be used easily for battery charging, while their grid integration requires a PCU with galvanic isolation. Most of available PCUs provide no galvanic isolation, or use relatively complicated topologies or four stage energy conversion for that purpose. The dc-dc converter proposed allows reducing the complexity of the PCU. Steady-state analysis shows that the converter is capable of regulating voltage in a wide range suitable for micro wind turbines, which is supported by experimental results within the input voltage range of 40-400 V. The prototype built for integration of a 1.3-kW PMSG-based micro wind turbine shows good performance over the entire 1:5 range of the given wind turbine output voltage. A study of efficiency and power losses was conducted according to the wind turbine power profile.
The proposed work aims to generate electricity by utilising the air flowing around the vehicle through the micro wind turbines (MWTs). In this case, the electricity produced can be used to charge up ...the battery or power up additional vehicle accessories, which increases the efficiency or/and range of the vehicle. Three driving cycles have been conducted to examine the model’s performance in moderate, highly dynamic and highway driving scenarios. The analytical works resulted in an 8.38%, 4.6% and 1.01% efficiency increase for the case of the Highway driving cycle (FTP), the new European driving cycle (NEDC) and the standardisation random test aggressive driving cycle (RTS), respectively when adding the micro wind turbines model. In terms of range analysis, 16, 11 and 2 km of the range were added to the full battery charge range of the vehicle when the vehicle was simulated for the case FTP, NEDC and RTS driving cycles scenarios, respectively. The results conclude that the value of micro wind turbines is shimming with highway driving scenarios where the effect of regenerative braking is absent and the drag force acting on the vehicle is at its highest rate.
Power generation using small wind turbines connected to AC grids has been gaining attention and contributions in recent years. As small wind turbines are connected to remote areas as support energy ...systems, there are not extensive contributions connecting those small turbines to AC grids. This paper presents the integration of a small wind generation system which is AC-grid-connected. The system is composed of a 160 W commercial small wind turbine with a permanent magnet synchronous generator and a 140 W Texas Instruments (Dallas, TX, USA) development kit devoted to connecting photovoltaic panels to AC grids. Several experimental tests were developed to characterize the devices, e.g., to obtain the power–current curves of the synchronous generator. Moreover, a mathematical model of the flyback converter is developed in detail in order to design a new converter controller. All the control capacity of the development kit is used to extract the maximum power of the synchronous generator, to reject the oscillation produced by the inverter and to connect the system to the AC grid. Experimental results show that is possible to integrate these devices to provide energy to power systems with some achievable adaptations.
•A design for swinging sail wind turbine is proposed.•The dynamical equations of the new turbine are derived and numerically solved.•The turbine performance and energy conversion efficiency are ...numerically investigated.•Effects of variations of different parameters on performance are examined.•The predicted performance of the new turbine and the power coefficient are described.
The increase in carbon dioxide concentration in the atmosphere and its detrimental effects has provided the incentive for the development of renewable energy resources. Wind energy is at the forefront of providing renewable energy alternatives. One of the attractive categories of wind turbines is the biomimetic oscillating wings. In the present study, a new oscillating wind turbine that works with a horizontally swinging sail in crosswind flows was proposed. The dynamical equations of the turbine were derived, and a computational model for solving the governing equations using quasi-steady aerodynamic data of a flat plate was developed. The computer code was used, and the time response of the turbine, the generated power, and the turbine performance were investigated. The aerodynamics results were validated using a computational fluid dynamics (CFD) approach. Effects of various parameters including oscillation period, mast length, flywheel inertia, resistive torque and spring constant were examined, and the stability chart of the turbine was determined. The predicted performance of the designed turbine agreed well with the expected behavior, and the estimated power coefficient was in the acceptable range for a micro-sized wind turbine suitable for working at low wind speeds.
•Comparison of thermal and electrical storage in reducing mismatch.•Comparison of solar tracking strategy and fixed tilt angle in reducing mismatch.•Influence of micro-wind turbine numbers and hub ...heights in reducing mismatch.•Simple payback time of micro-wind turbine and PV for single-family house.•Simple payback time when grid feed-in option is available.
This paper conducts analyses and proposes solutions for reducing mismatch between renewable energy (RE) production and electrical demand from a 150m2 single-family house. The RE options are photovoltaic (PV) and micro-wind turbine. This paper mainly focuses on the situation when grid feed-in is not available, but a brief economic analysis with grid feed-in is also conducted at the end of the paper. This paper specially investigates the influence of electrical storage in batteries and thermal storage in a domestic hot water (DHW) tank with suitable RE-DHW recharging strategies. The simulation results show that the recharging strategy of excess renewable electricity to a DHW storage tank with one day's DHW volume is more technically and economically effective than using electrical battery in reducing annual mismatch. Even without battery, the improvement in reducing mismatch can be 12.7–23.3% simply by using the RE-DHW recharging strategy. Furthermore, PV with 2-axis solar tracking strategy is not economically feasible in the Nordic climate, whereas south-facing PV with a 45° fixed tilt angle is recommended. Moreover, from both the energy and economic points of view, the increased hub height with multiple turbines is preferable for the application with a 6.64–16.2% improvement in reducing mismatch.
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