Ultra-high efficiency bidirectional WPT control between electric vehicle battery and power grid

• Main Author: Wang, Sicheng
• Other Authors: Tang Yi
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Wireless power transfer (WPT); V2G; Variable frequency phase shift control (VFPSC); Magnetic core design; NSGA-II
• Online Access: https://hdl.handle.net/10356/177459
• Institution: Nanyang Technological University

This dissertation incorporates the concept of Vehicle-to-Grid (V2G) into the WPT system and investigates the control strategy and coupler structure to apply it to electric vehicles, aims to design an efficient wireless power transfer solution with a focus on bidirectional power flow interaction and lightweight. Firstly, loosely coupled transformer theory is utilized to establish and calculate the gain characteristics for two types of symmetrical compensation networks: series-series (SS) and parallel-parallel (PP). By analyzing the load-independent operating points of these circuits, SS-WPT is selected as the main research subject. Subsequently, this report adopts a segmented charging method as the charging mode, and then a T-parameter model of the SS-WPT system is derived for analyzing the bidirectional power flow. Based on the T-parameter model the report applies a variable frequency phase shift control strategy for the V2G mode and analyzes the active and reactive power deviations under system deviation conditions, further optimizing the flow direction control parameters. In addition, a comprehensive dual-mode three-loop control scheme is established. Furthermore, this report utilizes NSGA-II algorithms and FEA simulation to design a planar magnetic core structure made of hybrid materials based on their physical behaviors. The proposed core could achieve a 7% weight reduction while ensuring high efficiency (96.81%). Finally, this report verifies the effectiveness of the proposed control strategy and the lightweight coupler design method through MATLAB/Simulink simulation and experiments.