Tianze Kan

A New Integration Method for an Electric Vehicle Wireless Charging System Using LCC Compensation Topology: Analysis and Design

There is a need for charging electric vehicles (EVs) wirelessly since it provides a more convenient, reliable, and safer charging option for EV customers. A wireless charging system using a double-sided LCC compensation topology is proven to be highly efficient; however, the large volume induced by the compensation coils is a drawback. In order to make the system more compact, this paper proposes a new method to integrate the compensated coil into the main coil structure. With the proposed method, not only is the system more compact, but also the extra coupling effects resulting from the integration are either eliminated or minimized to a negligible level. Three-dimensional finite-element analysis tool ANSYS MAXWELL is employed to optimize the integrated coils, and detailed design procedures on improving system efficiency are also given in this paper. The wireless charging system with the proposed integration method is able to transfer 3.0 kW with 95.5% efficiency (overall dc to dc) at an air gap of 150 mm.

Modeling and Analysis of AC Output Power Factor for Wireless Chargers in Electric Vehicles

This paper presents a general mathematical expression and characteristic analysis of the output power factor before rectification on the receiver side for wireless chargers in electric vehicles. This power factor is usually regarded as unity (i.e., the ac output voltage is in phase with the current), based on fundamental harmonic approximation. However, the default unity power factor assumption is not accurate for output power derivation even at resonance frequency. This study explores not only output power factor characteristics for different frequencies or power levels, but also the phase relationships of the input and output ac voltages. The continuous conduction mode and discontinuous conduction mode are both analyzed. An integrated LCC compensation topology is selected as the research object, and its analysis process can be readily extended to other common topologies. Furthermore, this study is beneficial for the implementation of some control strategies requiring precise power computation/estimation, e.g., feedforward control or model prediction control. Finally, a comparison of numerical and experimental results with various misalignment cases validates correctness of the proposed theoretical derivation and analysis methodology.

Design and Analysis of a Three-Phase Wireless Charging System for Lightweight Autonomous Underwater Vehicles

Lightweight autonomous underwater vehicles (AUVs), powered by rechargeable batteries, are widely deployed in inshore surveying, environmental monitoring, and mine countermeasures. While providing valuable information in locations humans have difficulty accessing, limited battery capacity of such systems prevents extended mission times. In order to extend mission times, this paper proposes a three-phase wireless charging system that could be used in a field-deployable charging station capable of rapid, efficient, and convenient AUV recharging. Wireless charging should not, however, affect instrumentation located inside the AUV. Thus, a three-dimensional finite element analysis tool is employed to study the characteristics of magnetic fields inside the AUV during three-phase charging. Simulation results reveal that the magnetic field generated by the proposed three-phase coil structure is concentrated away from the center of the AUV, where instrumentation would nominally be located. Detailed circuit analysis and compensation method to achieve resonance on both transmitters and receivers sides are also given. To validate the proposed concept, a three-phase wireless charging system is developed. Experimental results demonstrate that the system is able to transfer 1.0xa0kW with a dc–dc efficiency of 92.41% at 465xa0kHz.

A high efficiency and compact inductive power transfer system compatible with both 3.3kW and 7.7kW receivers

This paper proposes a high-efficiency, compact inductive power transfer (IPT) system for the stationary charging of electric vehicles, which contains a single transmitter and two receivers of different power. The transmitter is compatible with both 3.3kW and 7.7kW receivers. A double-sided LCC compensation circuit is adopted to realize the IPT system. In the magnetic coupler design, the external compensation inductors are integrated into the main coils without introducing extra magnetic couplings. The design procedure of the circuit parameters is provided, in which high system efficiency is maintained for both the 3.3kW and 7.7kW receivers. A prototype is implemented to validate the proposed system. The transmitter coil size is 500mm×500mm, the 3.3kW receiver coil size is 300mm×300mm, and the 7.7kW receiver size is 420mm×420mm. When the air-gap is 150mm, the 3.3kW receiver system achieves a dc-dc efficiency of 95.4%, and the 7.7kW receiver system achieves a dc-dc efficiency of 95.2%.

A three-phase wireless charging system for lightweight autonomous underwater vehicles

Lightweight autonomous underwater vehicles (AUVs), powered by rechargeable batteries, are widely applied in inshore survey, environmental monitoring, and mine countermeasures. In order to provide a convenient charging option for AUVs, a three-phase wireless charging system is proposed in this paper. Three-dimensional (3D) finite-element analysis (FEA) tool ANSYS MAXWELL is employed to demonstrate the magnetic characteristics and advantages of the proposed coil structure. Detailed circuit analysis and compensation method are also given. Furthermore, a three-phase wireless charging system is designed and tested. The system is able to deliver 1.0 kW at efficiency (overall dc to dc) of 92.41% at 465 kHz.