Design of a high-torque machine with two integrated motors axes reducing the electric vehicle consumption

The motorization of electric vehicle needs to work at a constant power on a wide range of speed. In order to be able to satisfy these requirements, we describe in this paper a solution, which consists in modifying of a simple structure of a permanent magnet motor by a double rotor structure integrating two motor axes into the same machine. This article describes, then, a design methodology of a permanent magnet motor with double rotor, radial flux, and strong starting torque for electric vehicles. This work consists on the analytical dimensioning of the motor by taking into account several operation constraints followed by a modelling by the finite elements method. This study is followed by the comparison between this motor and a motor with one rotor. A global model of the motor- converter is developed for the purpose to answer several optimisation problem

Combined design and control optimization of hybrid vehicles

Hybrid vehicles play an important role in reducing energy consumption and pollutant emissions of ground transportation. The increased mechatronic system complexity, however, results in a heavy challenge for efficient component sizing and power coordination among multiple power sources. This chapter presents a convex programming framework for the combined design and control optimization of hybrid vehicles. An instructive and straightforward case study of design and energy control optimization for a fuel cell/supercapacitor hybrid bus is delineated to demonstrate the effectiveness and the computational advantage of the convex programming methodology. Convex modeling of key components in the fuel cell/supercapactior hybrid powertrain is introduced, while a pseudo code in CVX is also provided to elucidate how to practically implement the convex optimization. The generalization, applicability, and validity of the convex optimization framework are also discussed for various powertrain configurations (i.e., series, parallel, and series-parallel), different energy storage systems (e.g., battery, supercapacitor, and dual buffer), and advanced vehicular design and controller synthesis accounting for the battery thermal and aging conditions. The proposed methodology is an efficient tool that is valuable for researchers and engineers in the area of hybrid vehicles to address realistic optimal control problems

Convex relaxations in the optimal control of electrified vehicles

When controlling the energy flow in electrified powertrains by means of convex optimization, the typically non-convex set of the original formulation needs to be relaxed to a convex super-set. In this paper we show that when using the backward simulation approach, where vehicle velocity is equal to the reference velocity, the global optimum of the original non-convex problem can be obtained by solving the relaxed convex problem. When vehicle velocity is kept as a state in the problem, in the so called forward simulation approach, we provide a condition for which, when satisfied, an agreement will be achieved between the solutions of the relaxed and the original problem

Comparative Study of PMSM and SRM Capabilities

International audienceThis paper is a synthesis of various research work performed on innovative structures for electrical machines (EM) responding to new performance requirements and applications. A presentation of the various statistical applications of EM will be made with various criteria. It will establish an initial comparison between the possibilities of both types of machines, namely the permanent magnet synchronous machine (PMSM) and switched reluctance machine (SRM), since more competing by conventional machines such as induction machines. It will be completed by a performance comparison study using a torque density criterion. Finally, an analytical-numerical method for PMSM and SRM structures design will be proposed

Electromobility Studies Based on Convex Optimization DESIGN AND CONTROL ISSUES REGARDING VEHICLE ELECTRIFICATION

This article presents a framework to study design tradeoffs in the search for electromobility solutions based on approximate modeling of the power flows in the powertrain as a function of component sizes. An important consequence of the modeling assumptions is that the optimal energy management and component sizes can be computed simultaneously in a convex program, which means that competing designs can be evaluated in an objective way, avoiding the influence of a separate control system design. The fact that the optimization problem is convex allows large problems to be solved with moderate computational resources, which can be exploited by, for example, running optimizations over very long driving cycles. The problem formulation also admits design decisions for the charging infrastructure to be included in the optimization

Design Parameter Analysis of Point Absorber WEC via an Evolutionary-Algorithm-Based Dimensioning Tool

Wave energy conversion has an essential difference from other renewable energies since the dependence between the devices design and the energy resource is stronger. Dimensioning is therefore considered a key stage when a design project of Wave Energy Converters (WEC) is undertaken. Location, WEC concept, Power Take-Off (PTO) type, control strategy and hydrodynamic resonance considerations are some of the critical aspects to take into account to achieve a good performance. The paper proposes an automatic dimensioning methodology to be accomplished at the initial design project stages and the following elements are described to carry out the study: an optimization design algorithm, its objective functions and restrictions, a PTO model, as well as a procedure to evaluate the WEC energy production. After that, a parametric analysis is included considering different combinations of the key parameters previously introduced. A variety of study cases are analysed from the point of view of energy production for different design-parameters and all of them are compared with a reference case. Finally, a discussion is presented based on the results obtained, and some recommendations to face the WEC design stage are given

Design and Control of a Multiphase Interleaving DC-DC Converter with Loss Optimizing Operating Strategies for Electric Vehicle

The drivetrain components of commercial electric vehicles include the battery pack, inverter, and electric machine. However, in such a drivetrain configuration, the inverter input voltage (DC-Link voltage) is equal to the battery voltage, which presents some drawbacks. Firstly, different values are required to achieve the optimum voltage level during the battery stack and electric machine design process. Secondly, the battery state of charge negatively impacts the electric machine operating area. Additionally, as it will be demonstrated in this work, reducing the DC-Link voltage lowers inverter power losses. In operating points where the necessary machine voltage is lower than the battery voltage rated value, a fixed DC-Link voltage equal to the battery voltage results in additional inverter losses. The focus of this work is on the design and analysis of a battery electric vehicle drivetrain using an additional DC-DC converter extension in it. Accordingly, the main objective is to investigate the energy efficiency benefits of shifting the operating points of the drivetrain components by placing a DC-DC converter between the battery and the inverter-fed machine. For this purpose, a multiphase interleaving converter is selected, and through comprehensive modeling of the drivetrain, the appropriate control system is designed and evaluated on the one hand, and loss optimizing operating strategies are developed on the other hand to take the most advantage of the integration of a DC-DC converter into the drivetrain

Optimizing Investment Planning For District Heating Coupling Of Industrial Energy Systems Using MILP

Industrial energy systems are being transformed to decrease energy costs, reduce emissions, and ensure security of supply. The increasing integration of renewable energies and industrial waste heat leads to complex and interconnected industrial energy systems. At the same time, the decarbonization of the heating sector is still in its infancy and possibilities are discussed to make excess heat from industrial companies available for building supply via district heating networks or to use district heating for thermal energy supply in the industrial sector. In this paper, we present an optimization-based investment planning approach to calculate the optimal dimensioning of a potential heat transfer station connecting industrial sites to district heating systems. The approach is based on a model library that includes typical components of industrial energy systems. Moreover, it integrates different energy demands such as heating, cooling, or electricity of production systems and sites as well as waste heat of production processes depending on predominant temperature levels. The approach manages to include transformation strategies of the industrial energy system by integrating different scenarios using regret optimization, giving decision makers a better overview of the impact of the investment in a heat transfer station on the overall factory planning. The approach is applied to the planning process of an industrial company. In the use case, a positive net present value shows the benefits of an investment in a heat transfer station. Moreover, energy costs and carbon dioxide emissions can be reduced over the planning horizon and through the higher utilization of waste heat as well as the more efficient use of energy systems

Multi-objective optimisation for battery electric vehicle powertrain topologies

Electric vehicles are becoming more popular in the market. To be competitive, manufacturers need to produce vehicles with a low energy consumption, a good range and an acceptable driving performance. These are dependent on the choice of components and the topology in which they are used. In a conventional gasoline vehicle, the powertrain topology is constrained to a few well-understood layouts; these typically consist of a single engine driving one axle or both axles through a multi-ratio gearbox. With electric vehicles, there is more flexibility, and the design space is relatively unexplored. In this paper, we evaluate several different topologies as follows: a traditional topology using a single electric motor driving a single axle with a fixed gear ratio; a topology using separate motors for the front axle and the rear axle, each with its own fixed gear ratio; a topology using in-wheel motors on a single axle; a four-wheel-drive topology using in-wheel motors on both axes. Multi-objective optimisation techniques are used to find the optimal component sizing for a given requirement set and to investigate the trade-offs between the energy consumption, the powertrain cost and the acceleration performance. The paper concludes with a discussion of the relative merits of the different topologies and their applicability to real-world passenger cars