Integrated Optimal Design of a Passive Wind Turbine System: An Experimental Validation

This work presents design and experimentation of a full passive wind turbine system without active electronic part(power and control). The efficiency of such device can be obtained only if the system design parameters are mutually adapted through an Integrated Optimal Design (IOD) method. This approach based on multiobjective optimization, aims at concurrently optimizing the wind power extraction and the global system losses for a given wind speed profile while reducing the weight of the wind turbine generator. It allows us to obtain the main characteristics (geometric and energetic features) of the optimal Permanent Magnet Synchronous Generator (PMSG) for the passive wind turbine. Finally, experiments on the PMSG prototype built from this work show a good agreement with theoretical predictions. This validates the design approach and confirms the effectiveness of such passive device

Model simplification and optimization of a passive wind turbine generator

In this paper, the design of a "low cost full passive structure" of wind turbine system without active electronic part (power and control) is investigated. The efficiency of such device can be obtained only if the design parameters are mutually adapted through an optimization design approach. For this purpose, sizing and simulating models are developed to characterize the behavior and the efficiency of the wind turbine system. A model simplification approach is presented, allowing the reduction of computational times and the investigation of multiple Pareto-optimal solutions with a multiobjective genetic algorithm. Results show that the optimized wind turbine configurations are capable of matching very closely the behavior of active wind turbine systems which operate at optimal wind powers by using a MPPT control device

Influence of PWM methods in semiconductor losses of 15kVA three-phase SiC inverter for aircraft applications

In near future, modern aircrafts will be more electrical, having more power converters in different applications. Inverters is one of the most common applications, which are used in actuators, cabin pressurization, among others. In order to significantly reduce weight, size and losses of these converters, disruptive technology such as Wide Bandgap components (SiC and GaN transistors) should be used. In this paper, we study the influence of SiC components in a 540V/15kVA inverter for motor driving applications. The approach proposed here starts by the dynamic characterization of SiC modules with the aim of obtaining accurate switching energies in order to precisely calculate semiconductor losses in three-phase inverters. Then, precise conduction and switching loss calculation is developed to verify the influence of PWM methods on losses of this converter. A generic 15kVA inverter setup is built. Experimental results in this setup confirm the characterization and loss calculation and shows the best PWM methods for specific aircraft applications

Robust design of a passive wind turbine system

The effectiveness of full passive Wind Turbine (WT) systems has been recently demonstrated. Such low cost and reliable structures without active control and with a minimum number of sensors can be efficient only if the system design parameters are mutually adapted through an integrated optimal design approach. Even if there is a good agreement between theoretical design models and an experimental prototype, it is relevant to evaluate the WT efficiency with respect to design variable variations. Thus, this work is devoted more specifically to the sensitivity analysis of a passive WT system according to electrical variable variations of the Permanent Magnet Synchronous Generator (PMSG). It also investigates the interest of a robust design approach for reducing the sensitivity of the WT efficiency to specific variable variations

Trade-off between Losses and EMI Issues in Three-Phase SiC Inverters for More Electrical Aircrafts

Power converters will only be effectively used in future aircrafts if they are compact, efficient and reliable. All these aspects can be improved by the use of disruptive technology such as the so-called Wide Bandgap (WBG) semiconductors made of Silicon Carbide (SiC) or Gallium Nitride (GaN). These components can switch much faster than their silicon counterpart, which can reduce converter losses and also decrease differential mode filter given the increase of switching frequency. However, such a fast commutation increases Electromagnetic Interference (EMI) issues in the converter and load connected to it. This paper shows the approach developed at the French Institute of Technology (IRT) Saint-Exupery, in order to evaluate the trade-offs between losses and EMI issues of three-phase inverters used in future aircraft applications. Given the high voltage DC bus of 540V, SiC MOSFETs are investigated and experimental results show the impact of these components on losses and EMI for different parameters

Optimization of Superplastic Forming Process of AA7075 Alloy for the Best Wall Thickness Distribution

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes

Optimal linear quadratic Gaussian control based frequency regulation with communication delays in power system

In this paper, load frequency regulator based on linear quadratic Gaussian (LQG) is designed for the MAPS with communication delays. The communication delay is considered to denote the small time delay in a local control area of a wide-area power system. The system is modeled in the state space with inclusion of the delay state matrix parameters. Since some state variables are difficult to measure in a real modern multi-area power system, Kalman filter is used to estimate the unmeasured variables. In addition, the controller with the optimal feedback gain reduces the frequency spikes to zero and keeps the system stable. Lyapunov function based on the LMI technique is used to re-assure the asymptotically stability and the convergence of the estimator error. The designed LQG is simulated in a two area connected power network with considerable time delay. The result from the simulations indicates that the controller performed with expectation in terms of damping the frequency fluctuations and area control errors. It also solved the limitation of other controllers which need to measure all the system state variables

Determinants Influencing Quality of Finance and Accounting Education: The Case Study of Vietnam

The quality of undergraduate program in general and in the discipline of finance and accounting in particular is one of the big concerned issues in society. For a long time, Vietnam has trained a large number of bachelor students which exceeds the real needs, especially in the field of economics. In the dimension of this study, we investigate the impact levels of determinants on quality of financial and accounting education in the context of the 4th Industrial Revolution. Data were collected by receiving questionnaire feedbacks from students of Trade Union University of Vietnam. By employing the tests of Cronbach’s Alpha, exploratory factor analysis and multivariate regression, the results show that four determinants including (i) role of trainers, (ii) innovation of the training program, (iii) applying information technology; (iv) and social behavior skills of students influence positively the quality of education in the field of finance and accounting. Keywords: Education quality, finance and accounting, Vietna

NUMERICAL SIMULATION TO STUDY EFFECT OF DIE DESIGN PARAMETERS ON DEFORMATION POSSIBILITY OF METAL ON COMBINED DRAWING

This paper uses numerical simulation to study amethod in combined drawing process with thinning the wall when drawing of a cylindrical cup of sheet metal. The software Deform 2D is used to examineeffect of die design parameters (inclination of die) on deformation possibility of metal. Simulation results in order to select appropriate die design parameters (conical die), to enhance the ability to deform and contribute to improve product quality

SOME RESULTS OF AIR MONITORING QUALITY IN HANOI AND ASSESSMENT OF AIR MONITORING METHODS USED IN VIETNAM

Joint Research on Environmental Science and Technology for the Eart