Aaron Gilchrist

A High Efficiency 5 kW Inductive Charger for EVs Using Dual Side Control

This paper presents the design of a 5 kW inductive charging system for electric vehicles (EVs). Over 90% efficiency is maintained from grid to battery across a wide range of coupling conditions at full load. Experimental measurements show that the magnetic field strength meets the stringent International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human safety. In addition, a new dual side control scheme is proposed to optimize system level efficiency. Experimental validation showed that a 7% efficiency increase and 25% loss reduction under light load conditions is achievable. The authors believe this paper is the first to show such high measured efficiencies for a level 2 inductive charging system. Performance of this order would indicate that inductive charging systems are reasonably energy efficient when compared to the efficiency of plug-in charging systems.

A review on inductive charging for electric vehicles

The scarce supply of fossil fuel in the mere future has driven the development of electric vehicles (EV) worldwide. Plug-in connectors have been commonly proposed for EV charging, however, these systems have disadvantages such as safety, esthete, and operation in snow. Therefore, a new method to inductively charge the vehicle without any physical contact has been proposed. This paper presents a state of the art literature review on the recent advancements of Inductive Power Transfer (IPT) technology used in EV charging. A possible future technology to solve the inherent range anxiety problem is also presented using roadway electrification and in-motion power transfer concepts.

A 90 percent efficient 5kW inductive charger for EVs

This paper presents the design of a 5kW inductive charging system for electric vehicles (EVs). Over 90% efficiency is maintained from grid to battery across a wide range of coupling conditions at full load. Experimental measurements show that the magnetic field strength meets the stringent International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human safety. In addition, a new dual side control scheme is proposed to optimize system level efficiency. Experimental validation showed that a 7% efficiency increase and 25% loss reduction under light load conditions is achievable. The authors believe this paper is the first to show such high measured efficiencies for a level 2 inductive charging system. Performance of this order would indicate that inductive charging systems are reasonably energy efficient when compared to the efficiency of plug-in charging systems.

Design of Symmetric Voltage Cancellation Control for LCL converters in Inductive Power Transfer Systems

This paper presents a new design strategy for Symmetric Voltage Cancellation (SVC) Control used in LCL converters for Inductive Power Transfer (IPT) Systems. It was found that the operating mode that eliminated diode reverse recovery losses in the H-bridge had particularly low losses. An analytical technique is used to calculate the operating modes. Three common control schemes used in LCL converters were computed and normalized graphs are produced to aid designers in making engineering tradeoffs between more efficient switching schemes, total harmonic distortion (THD) and the overall cost of the converter. For a typical LCL converter example, total losses in the H-bridge can be reduced by a factor of 11 by restricting operation to a mode with no diode reverse recovery loss.

Novel system for wireless in-motion EV charging and disabled vehicle removal

This paper proposes roadway electrification to facilitate wireless charging to accomplish two purposes. The system allows electric vehicles (EVs) traveling on an electrified lane to receive a charge update. It also permits charging of a low-profile autonomous emergency assist vehicle. Several vehicles of this type would be stationed along a congested roadway allowing an automated and quick response to clear incident situations such as roadway debris, abandoned or disabled vehicles, and minor accidents. It is anticipated that by accomplishing both EV charging and incident response, the system can help to reduce important problems of incident delay, injury and deaths to emergency response personnel, and petroleum related emissions. A case study using data from Washingtons State Route 520 indicates that the system can potentially save up to 50% of the induced delay due to incidents. The concept of operations for the system is described in the paper and aspects of technology readiness are explored.