Eric Bideaux

Thermal Network Model of Supercapacitors Stack

In the field of urban transport, supercapacitors are submitted to relative high charge and discharge currents and therefore significant heat generation occurs. It has been shown that the temperature has a great influence on the aging mechanism of supercapacitors and, by consequence, on the lifetime of the system. That is why the thermal management becomes a key issue in the study of the performance of a supercapacitors stack. In this paper, thermal modeling of a supercapacitors stack is presented and a matrix representation of the model is deduced. Validation of the model has been carried out using measurement on a developed test bench. Sensitivity of the model according to input uncertainties is finally discussed.

Adaptive Higher Order Sliding Modes for Two-dimensional Derivative Estimation

In this paper, some recent technical of the derivatives noisy transient signals estimation is extended to the two-dimensional case. This technique, which called higher order sliding modes is mostly used in the synthesis of robust controllers and is also shown a good results in the synthesis of the rth order robust dierentiators. In this work, such dierentiators are used as an edge detection method into image application. The proposed algorithm use an adaptive mechanism for tuning up its parameters in real time, in order to increase the efficiency of basic scheme. Some comparative study with a conventional methods of edge detection is performed.

Combinatorial approach for sizing and optimal energy management of HEV including durability constraints

This paper presents a combinatorial approach used to solve an optimization problem including component sizing and energy management control applied to an offroad hybrid electric vehicle with durability constraints. The problem under consideration is the optimization of the hybrid power supply system of an electric mini-excavator. It is composed of a fuel cell system and one energy storage system, i.e includes a lithium battery or a supercapacitors pack. The goal is to minimize the global cost of the machine during its entire working lifetime. In order to fulfill the requirements, an ageing model is included in the original problem to simulate the degradation of the battery and the fuel cell. The paper is focused on the reformulation of the nonlinear original problem into combinatorial subproblems. Then a branch and bound algorithm is applied to solve all sub-problems. Some results are presented to compare the different energy storages configurations.

Dynamic Gains Differentiator for Hydraulic System Control

This paper deals with online numerical differentiation of a noisy time signal where new higher order sliding mode differentiators are proposed. The key point of these algorithms is to include a dynamic on the differentiator parameters. These dynamics tune-up automatically the algorithm gains in real-time. Convergence properties of the new schemes are derived using a Lyapunov approach. Their effectiveness is illustrated via simulations and experimental tests, where comparative studies are performed between classical schemes and the new ones. Such algorithms are also used in the feedback control of an electrohydraulic system.

Electro-thermal sizing of supercapacitor stack for an electrical bus: Bond graph approach

This paper is devoted to the study of electro-thermal sizing of supercapacitors stack. The application concern the alimentation of trolleybus in case of electrical microcuts that frequently occurs during circulation of the trolleybus. The goal is to size the number of supercapacitor to be implemented knowing the speed and acceleration profile of the trolleybus and to discuss about the thermal performance of the obtained stack. Based on bond graph approach, direct and inverse model of the kinematic chain of trolleybus is developed in order to deduce the consumption of an electrical bus and the braking energy in relation with the speed profile. Validation of direct model has been carried out with experimental results. Then, based on the Ragone plot of supercapacitors, we study the number of supercapacitors needed to recover braking energy and to supply the bus in the case of electrical microcuts. Finally, A bond graph thermal model of the stack is developed and the efficiency of this model is validated based on experimental results on a test bench.

Game theoretic approach for electrified auxiliary management in high voltage network of HEV/PHEV

Auxiliary electrification becomes a potential solution to reduce the vehicle energy consumption. However, electrified auxiliaries operate mostly in individual way, non-cooperative in regardless of the vehicle state. In this paper, a new control strategy for electrified auxiliary system is proposed in order to improve the coordination among auxiliaries. This new control strategy is not only based on a game theoretic approach but also a model predictive control (MPC). In this approach, each electrified auxiliary is considered as a player participating in an energy consumption game, where players have incentive to cooperate and improve the global vehicle consumption. Simulation results on a plug-in hybrid electric vehicle show that this new control design provides a promising and simple approach to control the electrified auxiliary system.

Model Predictive Control Dedicated to an Electrified Auxiliary in HEV/PHEV

Auxiliary electrification in Hybrid Electric Vehicle (HEV) and Plug-in Hybrid Electric Vehicle (PHEV) represents a promising solution in energy management of vehicle. The work presented in the following paper focuses on the design of a controller able to reduce the electrical energy consumption of electrified auxiliaries during a driving cycle. A Model Predictive Control (MPC) is proposed and applied to the air supply system of a PHEV. A comparison of energy consumption between this method and two others (Hysteresis Control and Dynamic Programming) is carried out in order to verify the performance of the MPC controller. Numerical simulations show that this technique allows to obtain a significant gain on energy consumption compared to a standard Hysteresis Control. Furthermore, the difference in term of energy consumption between MPC and Dynamic Programming is weak.

Experimental Analysis of Air Jets for Sorting Applications

Pulsed air jets are used in the industry to eject objects in sorting operation and understand the jet establishment and its spatial characteristics is important to optimize the application. This paper presents a first experimental analysis of jets issued from a high speed solenoid valve in terms of pressure, temperature, and velocity. Results will be first shown for steady state flows at different pressure conditions inducing subsonic or supersonic air jets and compared to the literature. For a subsonic jet, the results confirm the topography proposed in the literature. For the supersonic jets, a subsonic topography was identified after the supersonic zone. These supersonic jets have a constrained diameter which is appreciated in order to perform sorting with precision. Then, first unstationary experimental results will be presented and commented. This first measurement of the jet development is encouraging, since it was possible to identify the different delays linked to the propagation time from the valve outlet to the measurement point on opening and closing.Copyright

Combined Kinetic and Potential Energy Recovery Solution Applied to a Reach Stacker

Reach stackers are heavy duty mobile machines mainly used for container handling on intermodal terminals or harbors. The increasingly restrictive legislation on pollutant emissions as well as the need to reduce fuel costs for operators motivate manufacturers to design more efficient machines. Previous studies highlighted three ways to improve the fuel consumption, namely: (i) improving the engine efficiency; (ii) recuperating the potential energy of elevated containers; (iii) recovering the kinetic energy of the vehicle during decelerations. The architecture proposed in this paper combines these three requirements while preserving most of the conventional components. It results in a moderately priced solution. Control strategies are also studied, especially focusing on the potential energy recovery system where an input-output linearization method is compared to a conventional linear controller. Simulation conducted on several duty cycles shows fuel savings of up to 18.4% and a good robustness to cycle variations.Copyright

Reynolds number–dependent mass flow rate calculation for pneumatic pipes:

In fluid power applications, pipes may have important effects on the system performances. In hydraulics, simple pipe models could give a good approximation of the pressure drop, but in pneumatics, accurate approximations are more complex because of the fluid compressibility. Therefore, simple but accurate models of air mass flow rate in pipes are still needed for system design and control purposes. The main contribution of this article is to propose a novel analytical formulation of the mass flow rate in pneumatic pipes by taking into account the pipe friction factor and more specifically its dependency on the flow Reynolds number. Accordingly, it makes it applicable to any circuit conditions (variable pressure at upstream or downstream pipe sides). The proposition here is a physically based adaptation of the flow approximations as defined in the first edition of the ISO 6358 standard and only uses the two conventional flow rate parameters; the novelty is to introduce a specific relationship between these flow parameters and the pipe friction factor. The proposed formulation provides a simple analytical way to predict accurately pipe behaviour in pneumatic circuits for sonic and subsonic flows. Based on this formulation, the calculated mass flow rates show a good agreement with measurements obtained with pipes of different diameters and lengths, even for variable upstream pressure conditions. Finally, limitations of existing formulations are discussed and advantages of the proposed approach highlighted.