More than a century-old gasoline internal combustion engine is a major contributor to greenhouse gases. Electric vehicles (EVs) have the potential to achieve eco-friendly transportation. However, the major limitation in achieving this vision is the battery technology. It suffers from drawbacks such as high cost, rare material, low energy density, and large weight. The problems related to battery technology can be addressed by dynamically charging the EV while on the move. In-motion charging can reduce the battery storage requirement, which could significantly extend the driving range of an EV. This paper reviews recent advances in stationary and dynamic wireless charging of EVs. A comprehensive review of charging pad, power electronics configurations, compensation networks, controls, and standards is presented.

Wireless Power Transfer for Vehicular Applications: Overview and Challenges

The profitable commercialization and fast adoption of electrified transportation require fast, economical, and reliable charging infrastructure. This paper provides a comprehensive, state-of-the-art review of all the wireless charging technologies for electric vehicle (EVs), characteristics and standards available in the open literature, as well as sustainable implications and potential safety measures. A comparative overview of conductive charging and wireless charging is followed by a detailed description of static wireless charging, dynamic wireless charging (DWC), and quasi-DWC. Roadblocks, such as coil design of power pads, frequency, power level limitations, misalignment, and potential solutions, are outlined. The standards are then tabulated to deliver a coherent view of the current status, followed by an explanation of the crux of these standards. Necessity and progress in the standardization of wireless charging systems are then deliberated. Vehicle-to-grid application of wireless charging is reviewed followed by an overview of economic analysis, social implications, the effect on sustainability, and safety aspects to evaluate the commercial feasibility of wireless charging. This paper will be highly beneficial to research entities, industry professionals, and investment representatives as a ready reference of the wireless charging system of EVs, with information on important characteristics and standards.

A Comprehensive Review of Wireless Charging Technologies for Electric Vehicles

Tensor Analysis of Networks. By Gabriel Kron. Pp. xxix, 635. 70s. 1965. (Macdonald)

A review of wireless power transfer for electric vehicles: Prospects to enhance sustainable mobility

In this study, a 3-kW inductive power transfer system is investigated, specifically intended for contactless vehicle charging. A series-series-compensated topology with dual-side power control and a corresponding control strategy is proposed to significantly increase the overall efficiency, especially for systems with large coupling factor variations and in partial load mode. The topology, which is closely related to the dual-active bridge converter, enables the dual-side power control without adding additional dc/dc converters to the system, and thus keeping the additional hardware effort minimal. A detailed analysis of the proposed topology is provided, and the benefits of the dual-side control are demonstrated both theoretically and experimentally. A hardware prototype is built and a peak dc-to-dc efficiency of 95.8% at 100 mm air gap and a minimal efficiency of 92.1% at 170 mm air gap is measured, including the power electronic components. The partial load efficiency at 500 W output power is still as high as 90.6% at 135 mm air gap. Overall, the proposed topology provides a practical method to overcome the main drawback of most single-side controlled inductive power transfer systems, which is a significant efficiency drop outside the nominal operating point.

A Dual-Side Controlled Inductive Power Transfer System Optimized for Large Coupling Factor Variations and Partial Load

This paper details the optimization of inductive power transfer (IPT) coil systems with respect to efficiency $\eta $ and area-related power density $\alpha $ as required in electric vehicle applications. Based on analytical calculations and finite-element models, which are discussed and experimentally verified in detail, generally valid design guidelines for high-power IPT systems are derived, and the $\eta $ - $\alpha $ -Pareto optimization of a scaled 5kW prototype system is presented. Experiments demonstrate a dc-to-dc conversion efficiency of more than 96.5% at a power density of 1.47kW/dm $^{2}$ with coils of 210mm diameter/52mm air gap, including the losses in the resonant capacitors and the power converter. Field measurements validate the predicted stray field with a calculation error of less than 10%.

Modeling and $\eta $ - $\alpha $ -Pareto Optimization of Inductive Power Transfer Coils for Electric Vehicles

Inductive Power Transfer (IPT) is well-established for applications with biomedical implants and radio-frequency identification systems. Recently, also systems for the charging of the batteries of consumer electronic devices and of electric and hybrid electric vehicles have been developed. The efficiency η of the power transfer of IPT systems is given by the inductor quality factor Q and the magnetic coupling k of the transmission coils. In this paper, the influence of the transmission frequency on the inductor quality factor and the efficiency is analyzed taking also the admissible field emissions as limited by standards into account. Aspects of an optimization of the magnetic design with respect to a high magnetic coupling and a high quality factor are discussed for IPT at any power level. It is shown that the magnetic coupling mainly depends on the area enclosed by the coils and that their exact shape has only a minor influence. The results are verified with an experimental prototype.

Optimized magnetic design for inductive power transfer coils

Inductive Power Transfer (IPT) has recently been proposed for application with Electric or Hybrid Electric Vehicles (EV/HEV), where a highly efficient system operation is demanded for the high-power transfer. Due to the high requirements on the regulation of the output power and the output voltage, and due to the large variations of the magnetic coupling, the control of these systems is a challenging task. In this paper, the frequency characteristics of a series-parallel compensated IPT system are discussed. Different control methods found in the literature are analyzed and a comparative evaluation of the current and voltage stress in the transmission coils, the resonant capacitors, and the semiconductors in the primary-side inverter is presented. It is shown that the dual control method offers a number of advantages in the controllability and potentially lower losses compared to the frequency control which is commonly used.

Comparative evaluation of control methods for Inductive Power Transfer

We present a space-domain integral-equation method for the analysis of periodic structures formed by three-dimensional (3-D) metallic objects arranged in a general skewed two-dimensional lattice The computation of the space-domain Green's function is accelerated using the Ewald transformation The method is validated on several periodic structures ranging from planar frequency-selective surfaces to 3-D photonic crystals and metamaterials For these structures, our technique shows a clear advantage in terms of computational speed when compared with available commercial softwares

/pdf/integral-equation-analysis-of-3-d-metallic-objects-arranged-188o2jtewz.pdf

Integral-Equation Analysis of 3-D Metallic Objects Arranged in 2-D Lattices Using the Ewald Transformation

Note: 110 pages Reference LEMA-REPORT-2009-001 Record created on 2009-09-11, modified on 2016-08-08

Ivica Stevanovic

Papers

Modeling and $\eta $ - $\alpha $ -Pareto Optimization of Inductive Power Transfer Coils for Electric Vehicles

Optimized magnetic design for inductive power transfer coils

Comparative evaluation of control methods for Inductive Power Transfer

Integral-Equation Analysis of 3-D Metallic Objects Arranged in 2-D Lattices Using the Ewald Transformation

Smart Antenna Systems for Mobile Communications