Research and Implement of PMSM Regenerative Braking Control for Electric Vehicle

As the society pays more and more attention to the environment pollution and energy crisis, the electric vehicle (EV) development also entered in a new era. With the development of motor speed control technology and the improvement of motor performance, although the dynamic performance and economical cost of EVs are both better than the internal-combustion engine vehicle (ICEV), the driving range limit and charging station distribution are two major problems which limit the popularization of EVs. In order to extend driving range for EVs, regenerative braking (RB) emerges which is able to recover energy during the braking process to improve the energy efficiency. This thesis aims to investigate the RB based pure electric braking system and its implementation. There are many forms of RB system such as fully electrified braking system and blended braking system (BBS) which is equipped both electric RB system and hydraulic braking (HB) system. In this thesis the main research objective is the RB based fully electrified braking system, however, RB system cannot satisfy all braking situation only by itself. Because the regenerating electromagnetic torque may be too small to meet the braking intention of the driver when the vehicle speed is very low and the regenerating electromagnetic torque may be not enough to stop the vehicle as soon as possible in the case of emergency braking. So, in order to ensure braking safety and braking performance, braking torque should be provided with different forms regarding different braking situation and different braking intention. In this thesis, braking torque is classified into three types. First one is normal reverse current braking when the vehicle speed is too low to have enough RB torque. Second one is RB torque which could recover kinetic energy by regenerating electricity and collecting electric energy into battery packs. The last braking situation is emergency where the braking torque is provided by motor plugging braking based on the optimal slip ratio braking control strategy. Considering two indicators of the RB system which are regenerative efficiency and braking safety, a trade-off point should be found and the corresponding control strategy should be designed. In this thesis, the maximum regenerative efficiency is obtained by a braking torque distribution strategy between front wheel and rear wheel based on a maximum available RB torque estimation method and ECE-R13 regulation. And the emergency braking performance is ensured by a novel fractional-order integral sliding mode control (FOISMC) and numerical simulations show that the control performance is better than the conventional sliding mode controller

Managing electric vehicles with renewable generation through energy storage and smart grid principles

Electric vehicles (EVs) are the most comprehensive method of sustainable transportation because they are environmentally friendly, quiet and low maintenance. However, they suffer from low usability because of the limited distance that can be covered on a single charge, which limits the freedom of transportation. Further, the charging process to restore the initial driving range is relatively long compared with conventional solutions. The only proposed way to improve the distance on a charge is to install a large energy storage system (ESS), which takes up more space, thereby limiting the usability of space by passengers and increasing the weight of the EV. The increased weight and size of the EV also negatively affect the distance range. In addition, the larger size of the battery, which is the main component of the ESS, requires a longer charging time. The current solution for fast charging requires more time than traditional refuelling techniques. This study aims to design, develop and analyse a novel approach for improving the energy consumption of EVs using optimisation techniques. In the first phase of the study, detailed analysis is conducted of the existing systems of EVs to determine which areas can be improved. The outcome of this investigation is used to determine presented loading profile of the various loads in EVs and determine the way to characterise them. These results are applied to design the new architecture for the loads to improve the connectivity of the various components of EVs and introduce interaction between loads. The developed architecture has centralised topology with separated control bus for the safety systems to satisfy the ISO 26262 safety standard. The newly developed system considers various loading requests at the same time to supply the load. The control algorithm schedules the power supply to the selected loads or, in some cases, clips the load request to decrease the momentary energy consumption. To achieve better optimisation, the thermal energy generation is analysed because it has a significant effect on the electric energy consumption in the heating elements. The second part of the developed approach is deep integration of loads with the overall energy flow in EVs. As a result, the recuperated energy in the propulsion system can be transferred to the components of the ESS and to supply the auxiliary loads on demand. The xviii generation units are combined with a photovoltaic system to improve the generation capability of the architecture. One of the key aims of this research is the simulation and experimental study of the developed architecture to identify weak spots in the solution and compare its performance with existing solutions under various solutions that go beyond traditional driving cycles