Brayima Dakyo

DC/DC Converter Design for Supercapacitor and Battery Power Management in Hybrid Vehicle Applications—Polynomial Control Strategy

This paper presents supercapacitor (SCAP) and battery modeling with an original energy management strategy in a hybrid storage technology. The studied dc power supply is composed of SCAPs and batteries. SCAPs are dimensioned for peak power requirement, and batteries provide the power in steady state. A bidirectional dc/dc converter is used between SCAPs and the dc bus. Batteries are directly connected to the dc bus. The originality of this study is focused on SCAP behavior modeling and energy management strategy. The proposed strategy is based on a polynomial (RST) controller. For reasons of cost and existing components (not optimized) such as batteries and semiconductors, the experimental test benches are designed in reduced scale. The characterized packs of SCAPs include two modules of ten cells in series for each one and present a maximum voltage of 27 V. The proposed strategy is implemented on a PIC18F4431 microcontroller for two dc/dc converter topology controls. Experimental and simulation results obtained from the polynomial control strategy are presented, analyzed, and compared with that of classical proportional-integral control.

Quasi-3-D analytical modeling of the magnetic field of an axial flux permanent-magnet synchronous machine

A quasi-three-dimensional (3-D) analytical model of the magnetic field in an axial flux permanent-magnet synchronous machine is presented. This model is derived from an exact two-dimensional analytical solution of the magnetic field extended to the 3-D case by a simple and effective radial dependence modeling of the magnetic field. The obtained quasi-3-D solution allows rapid parametric studies of the air-gap magnetic field. Then, analytical modeling of the cogging torque is presented. It is based on the obtained quasi-3-D analytical solution. Results issued from the proposed model in the air gap are compared with those stemming from a 3-D finite-element method simulation as well as with prototype measured values.

DC/DC and DC/AC Converters Control for Hybrid Electric Vehicles Energy Management-Ultracapacitors and Fuel Cell

This paper presents the ultracapacitors and the fuel cell (FC) connection for hybrid electric vehicles (HEVs) applications. An original method for the embedded energy management is proposed. This method is used to share the energetic request of the HEV between the ultracapacitors and the FC. The ultracapacitors are linked to dc-bus through the buck-boost converter, and the FC is connected to dc-bus via a boost converter. An asynchronous machine is used like traction motor or generator, and it is connected to dc-bus through an inverter. A dc-motor is used to drive the asynchronous machine during the decelerations and the braking operations. The main contribution of this paper is focused on the embedded energy management based on the new European drive cycle (NEDC), using polynomial control technique. The performances of the proposed control method are evaluated through some simulations and the experimental tests dedicated to HEVs applications.

Two-Dimensional Exact Analytical Solution of Armature Reaction Field in Slotted Surface Mounted PM Radial Flux Synchronous Machines

This paper presents an analytical solution for prediction of the armature reaction magnetic field in slotted surface mounted permanent magnet radial flux synchronous machines. This technique is used in the case of internal and external rotor radial-field machines. The magnetic field expressions are developed in both slots regions and magnetic airgap region leading to an exact calculation of the effects of slotting on the airgap magnetic quantities. Results from this analytical model are compared to corresponding finite element analyses. This analytical model is then used to estimate the self and mutual inductances.

Use of Ultracapacitors and Batteries for Efficient Energy Management in Wind–Diesel Hybrid System

The interconnection of the wind generator (WG) and the diesel generator (DG) induces some interactions on the common coupling point. These interactions are studied in this paper with the aim of identifying the system limits in performance and proposing an alternative solution. Due to the fast fluctuations of the WG and the DG slow dynamics, ultracapacitors and batteries are used for improving the hybrid system performances and reducing the fuel consumption. The dc-bus voltage is controlled by the diesel engine while providing a smoothed current. To ensure optimized life cycle cost and performance, a lifetime-estimation-based method is proposed. In this method, a rainflow counting method is applied to size the storage devices by taking into account the actual conditions of the system operation. The experimental test bench is designed in a reduced scale. Some simulations and experimental results are presented and analyzed.

Energy Management in the Decentralized Generation Systems Based on Renewable Energy—Ultracapacitors and Battery to Compensate the Wind/Load Power Fluctuations

This paper presents the energy management for the decentralized generation systems (DGS) using the wind turbine with photovoltaic (PV) panels and the energy storage devices. For a high penetration level of the wind/PV generation, the energy storage device with a fast response is necessary to cover the shortfall or overflow of generation due to sudden variations of the wind or the sun. In addition, the requested energy by the residential appliances presents random behavior, which can be lower or higher than the produced energy from the renewable sources. Using the wind turbine and the PV power generation system with energy storage will reduce the fluctuations of the wind power and the load ones. The energy storage system requires capital investment; thus, it is important to estimate the reasonable storage capacities without an overflow size for the desired applications. In addition, a good strategy for energy management is necessary to reduce the variation impacts of the wind energy and the load for the battery and the residential appliances. The contribution of this paper is focused on energy management based on the frequency approach using the wind/loads fluctuating power sharing and the polynomial controllers. First, this method enables reducing for the battery and the microgrid the impacts of the microcycles due to the wind/loads power fluctuations. Second, it allows estimating the energy storage capacity without the overflow size. The performances of the proposed method are evaluated through some simulations and experimental tests using the summer load profile and the winter ones.

Energy Management Based on Frequency Approach for Hybrid Electric Vehicle Applications: Fuel-Cell/Lithium-Battery and Ultracapacitors

This paper presents the ultracapacitors (U) and fuel-cell/lithium-battery connection with an original energy management method for hybrid electric vehicle (HEV) applications. The proposed method is focused on the frequency approach to meet the load energy requirement. The ultracapacitors are connected to the dc link through a buck-boost converter, and the fuel cell is connected to the dc link via a boost converter for the first topology. In the second topology, the lithium battery is connected to the dc link without a converter to avoid the dc-link voltage control. An asynchronous machine is used like the traction motor; it is related to the dc link through a dc/ac converter (inverter). The main contribution of this paper is focused on HEV energy management according to the dynamics (frequency) of the hybrid sources using polynomial correctors. The performances of the proposed method are evaluated through some simulations and the experimental tests, using the New European Driving Cycle (NEDC). This study is extended to an aggressive test cycle, such as the U.S. driving cycle (USDC), to understand the system response and the control performances.

Quasi-3D analytical modeling of the magnetic field of an axial flux permanent magnet synchronous machine

A quasi-three-dimensional (3D) analytical model of the magnetic field in an axial flux permanent magnet synchronous machine (AFPMSM) is presented. This model is derived from an exact 2D analytical solution of magnetic field extended to the 3D case by a simple and effective radial dependence modeling of the magnetic field. The obtained quasi-3D solution allows rapid parametric studies of airgap magnetic field. Then, an analytical modeling of the cogging torque is presented. It is based on the obtained quasi-3D analytical solution. Results issued from the proposed model in the airgap are compared with those stemming from a 3D finite elements method (FEM) simulation as well as with prototype measured values.

Analytical modeling of an axial flux permanent magnet synchronous generator for wind energy application

In this paper, an analytical modeling of an axial flux permanent magnet synchronous generator (AFPMSG) is investigated. The proposed model is based on an exact two dimensional (2D) solution of the magnetic field in the generator. Then, the generators quantities such as the phase electromotive force (EMF), the cogging torque and electromagnetic torque are written based on the developed exact 2D solution. To validate the proposed modeling, a 2D finite elements analysis (FEA) is performed, and results issued from the proposed model are compared with those stemming from a 2D FEA simulations. According to the simulation results, it is possible to evaluate the performance of the AFPMSG with reasonable accuracy via the developed analytical model

Wind Turbine Simulation Procedures

The main goal of this work is to develop specific procedures for implementation in wind turbine simulators designed especially for small machines. Using blade element methodology, we establish procedures for the torque and power characteristics of a small wind turbine, where some physical construction parameters are known. The algorithm is developed for two simulation procedures, which differ by the parameter used for the set of characteristics (wind speed or pitch angle).