LTE
Sainte-Foy-lès-Lyon, France
LTE
Sainte-Foy-lès-Lyon, France

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Cheng Y.,Harbin Institute of Technology | Bouscayrol A.,L2EP | Trigui R.,LTE | Espanet C.,University of Franche Comte | Cui S.,Harbin Institute of Technology
Journal of Electrical Engineering and Technology | Year: 2013

This paper presents the control of a Permanent Magnet Electric Variable Transmission (PM-EVT) for Hybrid Electric Vehicles (HEVs). Consisting of two electric machines, the EVT realizes the power split function in an electromagnetic way rather than in a mechanical way. A specific PM-EVT has been designed for Toyota Prius II. The control scheme of the entire vehicle is deduced using the Energetic Macroscopic Representation methodology. The energy management strategy yields local control references. A specific attention is paid for the field weakening for wide speed range. Simulation results are provided to illustrate the EVT modeling and control.


Cheng Y.,Lille University of Science and Technology | Cheng Y.,Harbin Institute of Technology | Bouscayrol A.,Lille University of Science and Technology | Trigui R.,LTE | Espanet C.,CNRS Femto ST Institute
2011 IEEE Vehicle Power and Propulsion Conference, VPPC 2011 | Year: 2011

As a novel series-parallel hybrid powertrain, the electric variable transmission (EVT) has gained much attention last years. With EVT, a power split function can be realized by changing its torque and speed in an electromagnetic way. Various machine types can be introduced into the concept of EVT. This paper will present a permanent magnet EVT (PM-EVT) with focus on its energetic modeling and control structure. Energetic Macroscopic Representation (EMR) is presented to be used to organize the connection between different elements of the PM-EVT. An inversion-based control is then deduced on the basis of EMR. Because the PM machines are more sensitive to operate in high speeds, field weakening is adopted. A simple energy management strategy has been developed in order to check the energetic modeling and the deduced control. © 2011 IEEE.


Vinot E.,LTE | Trigui R.,LTE | Cheng Y.,Lille University of Science and Technology | Cheng Y.,Harbin Institute of Technology | And 2 more authors.
2012 IEEE Vehicle Power and Propulsion Conference, VPPC 2012 | Year: 2012

This paper presents the application of optimal control to two series-parallel hybrid architectures. The dynamic programming method is applied to Toyota Hybrid System (THS) and a hybrid vehicle with Electric Variable Transmission (EVT). First the theoretical approach of dynamic programming and its application to SP-HEVs is presented. The way to take into account the extra degree of freedom, provided by the decoupling of wheel and engine, is presented. Then, the optimal fuel consumption of the two architectures is compared on different driving cycles for the case of a same reference vehicle Prius II. The over-consumption of the EVT topology is analysed and explained. © 2012 IEEE.


Le Lostec B.,LTE | Le Lostec B.,Université de Sherbrooke | Millette J.,LTE | Galanis N.,Université de Sherbrooke
International Journal of Thermal Sciences | Year: 2010

This paper presents an optimization study of a single stage absorption machine operating with an ammonia-water mixture under steady state conditions. The power in the evaporator, the temperatures of the external fluids entering the four external heat exchangers as well as the effectiveness of these heat exchangers and the efficiency of the pump are assumed fixed. The results include the minimum value of the total thermal conductance UAtot as well as the corresponding mean internal temperatures, overall irreversibility and exergetic efficiency for a range of values of the coefficient of performance (COP). They show the existence of three optimum values of the COP: the first minimises UAtot, the second minimises the overall irreversibility and the third maximises the exergetic efficiency. They also show that these three COP values are lower than the maximum COP which corresponds to the convergence of the internal and external temperatures towards a common value. The influence of various parameters on the minimum thermal conductance of the heat exchangers and on the corresponding exergy efficiency has also been evaluated. From an exergetic viewpoint it is interesting to reduce the temperature at the desorber and at the evaporator and to raise the values of that parameter at the condenser and the absorber. However these changes must be accompanied by an important increase in the total UA if it is desired to conserve a constant COP. The internal heat exchangers between the working fluid and the solution improve both the overall exergy efficiency and the coefficient of performance of the absorption apparatus. © 2010 Elsevier Masson SAS. All rights reserved.


Le Lostec B.,LTE | Galanis N.,Université de Sherbrooke | Millette J.,LTE
Renewable Energy | Year: 2013

An increased interest in absorption chillers has been observed [1] because these systems can utilize solar, geothermal and biomass energy sources, but also because they are quiet, vibration-free, require little maintenance and are ecological [2]. Instead of a compressor system, which uses electricity, an absorption cooling system, using renewable energy and kinds of waste heat energy, may be used for cooling. This paper presents the simulation of a single stage solar absorption chiller operating with an ammonia-water mixture under steady state conditions. This simulation is based on heat and mass balances for each component. The heat and mass transfers in the absorber, the condensation of binary vapor of ammonia-water in the condenser and a thermosyphon desorber placed under the purification column were modeled. The numerical model was compared and validated with experimental data obtained with a solar absorption chiller. The calculated results agree well with experimental data. Simulations based on experimental data were used to predict the temperature and concentration profiles in each heat exchanger. A parametric study was conducted to investigate the effect of evaporator and desorber temperature on the absorption chiller's performance. The COP decreases by 25% with a decrease of 10°C in evaporator temperature and the COP increases by 4% with an increase of 10°C in desorber temperature. © 2013 Elsevier Ltd.

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