TITLE:

High Efficiency Wireless EV Charger Based on Capacitive Power Transfer Principle

DATE:

Friday, October 23, 2015

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Dr. Chris Mi. Director of the Department of Electrical and Computer Engineering, San Diego State University

ABSTRACT:

Capacitive power transfer (CPT) and inductive power transfer (IPT) are two effective methods to transfer power wirelessly. The CPT technology utilizes high-frequency alternating electric filed to transfer power without direct electric connection, while the IPT system uses magnetic field to transfer power. The IPT technology has already been widely used in many applications, such as portable electronic devices, biomedical devices, and electric vehicle charging. Compared with the IPT system, the CPT system has many advantages. Magnetic fields are sensitive to nearby metal objects and the system efficiency drops quickly with this interference. It can generate eddy current losses, and hence heats in a conductive object, which creates a potential fire hazard. However, the electric filed in the CPT system does not generate significant losses in the metal objects.

Compared with previous work, this paper focus on 150mm distance power transfer by capacitive coupling. It is essentially designed for electric vehicle charging application. At this large distance, the coupling capacitance is typically at pF range. The series resonance topology is no longer suitable. In this presentation, a double-sided LCLC-compensated topology and its design process are proposed. Two pairs of metal plates are utilized to form two coupling capacitors to transfer power wirelessly. The LCLC-compensated structure can dramatically reduce the voltage stress on the coupling capacitors and maintain unity power factor at both the input and output. A 2.4kW CPT system is designed with four 610mm × 610mm copper plates and an air gap distance of 150mm. The experimental prototype reaches a dc-dc efficiency of 90.8% at 2.4kW output power. At 300mm misalignment case, the output power drops to 2.1kW with 90.7% efficiency. With a 300mm air gap distance, the output power drops to 1.6kW with 89.1% efficiency.

HOST:

Dr. Jose Castillo

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