71 research outputs found
4-HyÂdroxy-3-[(E)-3-phenylÂprop-2-enoÂyl]-2H-chromen-2-one
In the title molÂecule, C18H12O4, the phenyl ring is twisted by 23.2â
(1)° from the mean plane of the chromene system. In the crystal, weak interÂmolecular CâHâŻO hydrogen bonds link molÂecules into zigzag chains extending in the [010] direction. An intraÂmolecular OâHâŻO hydrogen bond is also present
Comparative Analysis of Estimation Techniques of SFOC Induction Motor for Electric Vehicles
International audienceThis paper presents system analysis, modeling and simulation of an electric vehicle with different sensorless control techniques. Indeed, sensorless control is considered to be a lower cost alternative than the position or speed encoder-based control of induction motors for an electric vehicle. Two popular sensorless control methods, namely, the Luenberger observer and the Kalman filter methods are compared regarding speed and torque control characteristics. They are also compared against the well-known model reference adaptive system. Simulations on a test vehicle propelled by 37-kW induction motor lead to very interesting comparison results
A Loss-Minimization DTC Scheme for EV Induction Motors
International audienceThis paper proposes a strategy to minimize the losses of an induction motor propelling an electric vehicle (EV). The proposed control strategy, which is based on a direct flux and torque control scheme, utilizes the stator flux as a control variable, and the flux level is selected in accordance with the torque demand of the EV to achieve the efficiency-optimized drive performance. Moreover, among EV's motor electric propulsion features, the energy efficiency is a basic characteristic that is influenced by vehicle dynamics and system architecture. For this reason, the EV dynamics are taken into account. Simulation tests have been carried out on a 1.1-kW EV induction motor drive to evaluate the consistency and the performance of the proposed control approach
Design and Implementation of an Electric Differential for Traction Application
International audienceThe use of an Electric Differential (ED) constitutes a technological advance in vehicle design along with the concept of more electric vehicles. EDs have the advantage of replacing loose and heavy mechanical differentials and transmissions with lighter and smaller electric motors directly coupled to the wheels via a single gear or an in-wheel motor. This paper deals then with an Electric Differential System (EDS) for an Electric Vehicle (EV) directly driven by dual induction motors in the rear wheels. A sensorless control technique is preferred to a position or speed encoder-based control one to reduce the overall cost and to improve the reliability. The EDS main feature is the robustness improvement against system uncertainties and road conditions. The EDS control performances are validated through experiments on a dSPACE-based test bench. The experimental results show that the proposed controller is able to track the speed reference and the curvature angle with good static and dynamic performances
Sliding Mode Control of EV Electric Differential System
International audienceThis paper describes the sliding mode control of an electric differential system for Electric Vehicle (EV) with two induction motor drives (one for each wheel). In this case, the electric differential will manage the speed difference between the two wheels when cornering. The proposed sliding mode control approach is evaluated on an EV global model taking into account the vehicle dynamics. Simulations have been carried out on a test vehicle propelled by two 37-kW induction motors to evaluate the consistency and the performance of the proposed control approach. The commonly used European drive cycle ECE-15 is adopted for simulation. The obtained results seem to be very promising
Analysis, Modeling and Neural Network Traction Control of an Electric Vehicle without Differential Gears
International audienceThis paper presents system analysis, modeling and simulation of an EV with two independent rear wheel drives. The traction control system is designed to guarantee the EV dynamics and stability in case of no differential gears. Using two electrics in-wheel motors give the possibility to have a torque and speed control in each wheel. This control level improves the EV stability and the safety. The proposed traction control system uses the vehicle speed, which is different from wheels speed characterized by slip in the driving mode, an input. In this case, a generalized neural network algorithm is proposed to estimate the vehicle speed. In terms of the analysis and the simulations carried out, the conclusion can be drawn that the proposed system is feasible. Simulation results on a test vehicle propelled by two 37-kW induction motors showed that the proposed control approach operates satisfactorily
Comparative Analysis of Control Techniques for Efficiency Improvement in Electric Vehicles
International audienceThis paper presents system analysis, modeling and simulation of an Electric Vehicle (EV) with three different control strategies: Field Oriented Control (FOC), Direct Torque Control (DTC), and DTC using Space Vector Modulation (DTCSVM). The objective is to assess the control strategy impact on the EV efficiency taking into account the vehicle dynamics. Indeed, among EV motor electric propulsion features, the energy efficiency is a basic characteristic that is influenced by vehicle dynamics and system architecture. Simulation tests have been carried out on a 37-kW EV that consists in an induction motor with a three-level IGBT inverter. Preliminary results seem to indicate that the DTC-SVM scheme is the best candidate
Modeling, Analysis, and Neural Network Control of an EV Electrical Differential
International audienceThis paper presents system modeling, analysis, and simulation of an electric vehicle (EV) with two independent rear wheel drives. The traction control system is designed to guarantee the EV dynamics and stability when there are no differential gears. Using two in-wheel electricmotorsmakes it possible to have torque and speed control in each wheel. This control level improves EV stability and safety. The proposed traction control system uses the vehicle speed, which is different from wheel speed characterized by a slip in the driving mode, as an input. In this case, a generalized neural network algorithm is proposed to estimate the vehicle speed. The analysis and simulations lead to the conclusion that the proposed system is feasible. Simulation results on a test vehicle propelled by two 37-kW induction motors showed that the proposed control approach operates satisfactorily
Normative reference and cut-offs values of maximal aerobic speed-20Â m shuttle run test and maximal oxygen uptake for Tunisian adolescent (elite) soccer players
This study aimed to develop reference curves of aerobic parameters of 20 m shuttle run test for
Tunisian soccer players. The study was conducted in the 2022/2023 pre-season. The reference
curves of the maximal aerobic speed (MAS) and the maximal oxygen uptake (VO2max) were
developed according to the Lambda, Mu and Sigma (LMS) method, using data from 742 Tunisian
premier league soccer players aged 11â18 years. Measured variables included: weight, height,
body mass index and maximal heart rate (HRmax). HRmax was measured when the participants
completed the maximal aerobic speed. VO2max was estimated using the 20 m shuttle run test
protocol (speed increment every minute). Our results presented the smoothed percentiles (3rd,
10th, 25th, 50th, 75th, 90th and 97th) of MAS (km/h) and VO2max (ml/kgâąminâ»1) according to
age. In addition, raw data showed that VO2 max was positively correlated with age (r = 0.333; P
< 0.001), height (cm) (r = 0.279; P < 0.001), weight (kg) (r = 0.266; P < 0.001), practice period
(years) (r = 0.324; P < 0.001) and BMI (kg/m2) (r = 0.10; P < 0.05). However, it was negatively
correlated to HRmax (bpm) (r = 0.247; P < 0.001). Only the measurements within the age
group [12â12.99] are significantly higher (p < 0.001; ES = 0.63) compared with the previous age
group [11â11.99]. Finally, regarding prevalence, our findings showed that 15.5 % of the players
in our sample had VO2max values above the 87.7th percentile cut-off, while only 0.3 % exceeded
the 99.18th percentile. The development of normative curves could help coaches and physical trainers to more accurately detect weaknesses in the aerobic performance of their players in order
to sustain high-intensity repetitive actions during a soccer match.info:eu-repo/semantics/publishedVersio
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