Abstract

Several technologies have been applied to electric vehicles (EVs) to achieve high performance in terms of mileage, speed, and efficiency. However, technological advances and customer demand are constantly revolutionizing the transportation sector. From the conventional internal combustion engine (ICE) vehicles, transportation has reached the area of hybrid electric vehicles (HEVs) and has moved towards fuel cell electric vehicles (FCEVs). Throughout this revolution, electric machines (EMs) made considerable progress. While the ICEs are phasing out because of their efficiency limitations and negative environmental impact, the EMs will remain the fundamental component of EVs. Hybrid topologies have been adopted and optimized by the industry to address several challenges related to efficiency, mileage, and ecology. However, the green transportation trend will undoubtedly lead to dominance of battery and fuel cell electric vehicles. Efficient high-speed EMs and their associated power electronics and control are therefore needed to replace and transcend ICEs.
The requirement of high-speed EMs that can replace and surpass the ICE in terms of efficiency versus speed range requires associated power electronic converters that can drive the EMs through their operating envelopes. The new generation of EVs will be more demanding in terms of power, integration to the grid, efficiency, mileage; ruggedness and size reduction of power electronics interfaces and machines. The aim is to reduce the overall cost/weight of EVs and optimize energy efficiency across the entire drivetrain.
This research proposes and validates a new step-by-step design method for EV drivetrain design and testing. The proposed method is based on analytically obtaining feasible drivetrain parameters from the torque-speed curve and battery nominal voltage specifications. A case study based on a 2010 Toyota Prius motor is used to validate the proposed approach for its ability to estimate feasible parameters that can be matched using finite element analysis (FEA) software. The proposed method's ability to estimate IPMSM parameters from a given SPMSM is validated
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experimentally. This method allows machines and drive specialists to work in parallel on the drivetrain component design and speed up the whole drivetrain design process.
A novel integrated multipurpose power electronics interface (IMPEI) designed for PHEVs and EVs is proposed to provide a solution to the increasing need for integration and grid support of EVs. The IMPEI is analyzed, designed, prototyped, tested, and compared with several other integrated power electronics interfaces (IPEIs) and with conventional power electronics interfaces (CPEI) in this work. The proposed IMPEI and different other topologies are compared in terms of configuration, device count, cost, and efficiency, using the BMW i3 as the benchmark application. The design requirements of the IMPEI are presented and discussed, including modes of operation, switch and passive element sizing, and ratings. The results of experiments in propulsion, regenerative braking, and single-phase and three-phase V2G and G2V are presented. The experimental efficiency analysis and comparison are carried out in the propulsion, V2G, and G2V modes.
The proposed analytical drivetrain design approach is used to size the drivetrain of a Renault Twizy. In this design, the IMPEI is used as a drive inverter. The potential fuel economy of the IMPEI-based Renault Twizy drivetrain is investigated based on experimental and simulation data. The IMPEI is sized and simulated in PSIM software to obtain its efficiency map throughout the operating envelope. The designed PMSM efficiency map is obtained from JMAG software. However, the mechanical system efficiency map is obtained practically throughout a drive cycle in Aachen city in Germany. A fuel economy analysis is also carried out in this work.
A comparison of commonly used test benches is provided, followed by the details on the test bench used to obtain the experimental results throughout the thesis. The main components of the test bench are described. Also, a regenerative braking analysis of high-speed permanent magnet synchronous motors (PMSMs) during emergency conditions is presented. Overloading the electric machine during regenerative braking in emergency conditions using field-oriented control (FOC) is investigated.