Ph.D. Dissertation Defense: Arun Sankar Uma Sankar
Wednesday, June 26, 2019
301 405 0680
Announcement: Ph.D. Dissertation Defense
Name: Arun Sankar Uma Sankar
Prof. Alireza Khaligh, Chair/Advisor
Prof. Robert Newcomb
Prof. Neil Goldsman
Prof. Kevin Daniels
Prof. Patrick McCluskey, Dean's representative
Date/Time: Wednesday, June 26, 2019, at 11 AM - 1 PM
Place: 2328, A.V. Williams Building
Title: Integrated Inductive and Conductive Charging System for Electric Vehicles
Global electric vehicle (EV) market acceleration is facilitated by supporting policies deployed by governments and cities to reap multiple benefits in the fields of transport decarbonization, air pollution reduction, energy efficiency and security. Currently conductive chargers are a customary method of storing electric energy into the storage elements present onboard of EV which is inadequate in supporting complete autonomy. Thriving inclination towards design of autonomous vehicles have shaped wireless charging as an attractive solution in favor of complete autonomy. Until the wireless charging infrastructure as well as interoperability standards are not completely developed, wired and wireless chargers have to co-exist onboard the vehicles for user convenience. Incorporation of an entire parallel wireless charging system on-board an EV, either during manufacturing or after-market increases size, weight, or cost, while declining the electric range of vehicle. Current requisite for multiple on-board charging options motivates the necessity for a solution efficiently integrating wired and wireless charging systems.
In this PhD research we propose multiple charging architectures capable of integrating inductive and conductive charging systems. The proposed architectures merge the output rectifying stage of inductive charging system to the existing on-board charger eliminating the additional weight and volume associated with wireless charger. Since the proposed system involves multiple power conversion stages, a system level study is carried out to select feasible topologies capable of maximizing the efficiency of integrated system. Additionally, an extended harmonic approximation (EHA) technique is introduced to increase the accuracy of resonant converter model facilitating the optimized design parameter selection of inductive charging system. Furthermore, a novel analog synchronous rectification circuit is proposed and designed to enable active rectification maximizing power transfer efficiency.
For proof of concept verification, a laboratory prototype of a 3.3kW Silicon Carbide (SiC) based integrated wireless charger is developed that can be interfaced to a variable input voltage (85-265 Vrms) 50/60Hz AC grid. According to the experimental measurements, the charger draws an input current with total harmonic distortion of 1.3% while achieving an overall efficiency of 92.77% at rated output power.