Wireless power system
A method for wirelessly or conductively (non-wireless) providing AC or DC power in AC or DC load applications and bidirectional applications.
Asa, Erdem↗
Engineering topics
Onar, Omer C.
Publications and source records attributed to Onar, Omer C..
Medium-Duty Delivery Truck Integrated Bidirectional Wireless Power Transfer System With Grid and Stationary Energy Storage System Connectivity
Electric vehicles (EVs) can provide power to the grid or buildings similar to distributed energy resources (DER) for energy balancing applications or optimizing the operation of the microgrids in harmony with the other DER assets. This article presents the operating modes of a bidirectional wireless power transfer (WPT) system designed for a medium-duty package delivery vehicle. The WPT system designed for this study can transfer 20 kW of power across 11 in of air gap using custom-designed double-D (DD) couplers with LCC–LCC tuning networks. The proposed system utilizes a 480-V three-phase grid connection, a plug-in hybrid delivery truck with bidirectional WPT, and a stationary energy storage system (SESS) that can be connected to the primary-side dc link. Due to the differences in primary and secondary dc bus voltages, and considering the voltage of the SESS, asymmetric voltage gains were used in the system. Sensitivity analyses of this system with respect to these voltage levels are presented. Five different operating modes of the grid, SESS, and the EV battery are investigated with experimental results. Control algorithms are described for grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operating modes. A bidirectional WPT system is operated with a power factor of 0.99 on the grid side in every operating mode. The EV battery was charged with 20.3 kW with an overall efficiency of 93.02% in the G2V operating mode. Finally, in the V2G operating mode, the WPT system provided 12.82 kW of power back to the grid with an overall efficiency of 89.08%.
25 ENERGY STORAGE↗
Tuning circuitry for a wireless power system
A wireless power supply power supply including first tuning circuitry coupled directly to a transmitter, the first tuning circuitry including an LCC configuration. The wireless power supply may include second tuning circuitry coupled directly to switching circuitry (e.g., an inverter) of the power supply, where the second tuning circuitry may be operable to direct power from the switching circuitry to the first tuning circuitry for supply to the transmitter, and where the second tuning circuitry includes a reactance operable to establish inductive operation of the switching circuitry at the switching frequency of the switching circuitry.
Pries, Jason L.↗
Sensitivity Analysis of a Polyphase Wireless Power Transfer System under Off-Nominal Conditions
Misaligned and/or variable coil airgaps cause coupling coefficient variation in wireless power transfer (WPT) systems, resulting in a decrease in the system’s transmitted power and efficiency. This paper presents sensitivity analyses of a three-phase, Y-Y connected, series-tuned WPT system in the frequency domain in terms of several different electric vehicle wireless charging off-nominal conditions (misalignments in Δ x and Δ y directions, change of airgap Δ z , and the roll Δψ, pitch Δθ, and yaw ΔΦ angles) as specified in Society of Automotive Engineers (SAE) J2954 Standard. Coil inductance matrices were obtained by measuring the self- and mutual inductances of the primary and secondary coil phase windings at variable airgap classes (from 5 cm to 30 cm) for five different charging positions as identified in SAE J2954. These 6 × 6 inductance matrices were used in sensitivity and Plexim/PLECS simulation analyses. The sensitivity of the WPT system was analyzed analytically using the input impedance and phase angle, voltage gain, current gain, quality factor, and coupling coefficient parameters of the series-tuned WPT system. The results were confirmed experimentally on a 50 kW WPT system.
42 ENGINEERING↗
Wireless power system
A method for wirelessly or conductively (non-wireless) providing AC or DC power in AC or DC load applications and bidirectional applications.
Asa, Erdem↗
Severe Temperature Impact Study on Ferrite Electromagnetic Shielding for Wireless Electric Vehicle Charging
Wireless charging of an electric vehicle (EV) is an emerging technology that enables noncontact charging, which has advantages in terms of convenience and flexibility. However, the embedded charging pads under and on the ground expose the charging coils, ferrite shielding, and related components to a potentially severe external environment. To study the electromagnetic shielding performance under such extreme temperature conditions, ferrite shielding material's permeability characteristics are tested under temperatures as low as -50°C to as high as 240°C. Referring to the official recorded lowest and highest temperature of the United States, in this paper, it is assumed that the operation temperature ranges from -50°C to 57°C as the coldest winter and hottest summer environment for WPT application. Electromagnetic performance, shielding, and associated stray magnetic emissions are simulated by using three-dimensional (3D) transient simulations to study the impact of low and high temperature on electromagnetic shielding performance. Based on ferrite testing data, from -50°C low temperature to 57°C high temperature, the ferrite's relative permeability ranges from 2550 to 3727. The simulation study indicates that there won't be significant impact on the EM shielding performance for WPT operated under those severe environment temperature conditions.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Wireless power system
A method for wirelessly or conductively (non-wireless) providing AC or DC power in AC or DC load applications and bidirectional applications.
Asa, Erdem↗
Magnetic Shield Design for the Double-D Coil-Based Wireless Charging System
In this work, magnetic field emission (MFE) of the high-power double-D (DD) coil-based wireless charging system is investigated and a shielding technique is proposed. The MFE pattern produced by the DD coils is significantly different from the MFE of the unipolar (e.g., circular, square, or rectangular) coils, and the traditional aluminum shield does not suppress the MFE from the DD coils. This study shows that a conventional aluminum shield increases the MFE, and a magnetic shield effectively suppresses the MFE of the DD coils. Therefore, a magnetic shield consisting of high-permeability magnetic material, such as ferrites, nanocrystalline, etc., is proposed for the DD pads. The shielding effectiveness of the proposed shield is evaluated through finite element analysis and verified through experiments. An 11 kW DD coil-based wireless charging system was used to test the proposed shielding technique. The experimental results show that a traditional aluminum shield increased the MFE by 29.8%, and the proposed magnetic shield suppressed the MFE by 50.5%.
42 ENGINEERING↗
Quasi-Dynamic Electromagnetic Field Safety Analysis and Mitigation for High-Power Dynamic Wireless Charging of Electric Vehicles
Dynamic wireless charging of electric vehicles (EV) is an emerging charging technology to enable non-contact wireless charging while the vehicle is moving. Compared to stationary wireless charging, in-motion wireless charging involves dynamic processes in which an EV is passing over the charging pads (transmitters). This in motion process makes the dynamic electromagnetic (EM) environment more complicated, and EM safety needs to be ensured under all circumstances. This is due to the fact that the entire vehicle body may be exposed to magnetic fields while the vehicle moves over the energized transmitter. This paper investigates several typical charging scenarios when EVs approach, pass over, and move away from the charging pads. Quasi-dynamic models, which are preliminarily verified by coils’ inductance measurements, are developed to analyze the dynamic process. Based on the quasi-dynamic analysis, shielding solutions are also studied to ensure EM safety for the dynamic wireless charging processes.
24 POWER TRANSMISSION AND DISTRIBUTION↗
A Field Enhancement Integration Design Featuring Misalignment Tolerance for Wireless EV Charging Using LCL Topology
This article proposes a magnetic integration design for EV wireless power transfer (WPT) systems, where the compensation and transmitting coils overlap one on top of the other to share the ferrite layer without any decoupling consideration. The magnetic field generated by both the compensation and transmitting coils are exploited to transfer power. To this end, a compensation method is proposed to enable magnetic field enhancement without any reactive power flow between the compensation and the transmitting coils, and to achieve input zero phase angle and constant current output. In addition, an efficient finite element analysis-based coil optimization algorithm is proposed to improve the coil misalignment tolerance on the horizontal plane, in which a reversely connected inner coil is used to stabilize the system output under misalignment conditions. Analytical and simulation results confirm transmission flux density enhancement and reduced leakage field characteristics of the proposed coil design. Finally, a scaled-down WPT prototype is built and tested to verify the performance and effectiveness of the design. The proposed design achieves 91.17% efficiency and misalignment tolerance up to 200 mm in any XY-direction while maintaining the power transfer and its efficiency. The results of this work provide insights into magnetic integration design of high-order compensation topologies featuring higher compactness, less ferrite usage, magnetic field enhancement, and misalignment tolerance for WPT systems.
42 ENGINEERING↗
Electromagnetic Shielding Design for 200 kW Stationary Wireless Charging of Light-Duty EV
Wireless power transfer (WPT) is a developing technology with the advantage of convenience and flexible charging. SAE recommended practice J2954 defines typical size and geometry with aluminum or ferrite plate shielding to limit leakage electromagnetic (EM) fields for WPT with power levels lower than 22 kVA from the input side. However, as the WPT power goes up to 100- or 200-kW level, EM safety surrounding the WPT becomes a critical concern. To address this oncoming safety challenge, a novel ferrite shielding design is proposed in this paper. Different misalignment scenarios in accordance with definitions in SAE J2954 are also taken into consideration to ensure EM safety under various operation scenarios. Simulation results, which are preliminarily verified by magnetic field measurements at 1.1 m from the center of the vehicle side coil under 100 kW operation, indicate that the magnetic field leakage can be maintained below the limits defined in SAE J2954 for 200 kW operation. A 3.3 kW scale-down test was also carried out and compared to parallel scale-down simulations. 26.8% field emission reduction is observed from the scale-down test, which supports the effectiveness of the proposed shielding design.
25 ENERGY STORAGE↗
Electrification Annual Progress Report (FY2019)
During fiscal year 2019 (FY 2019), the U.S. Department of Energy (DOE) Vehicle Technologies Office (VTO) funded early stage research & development (R&D) projects that address Batteries and Electrification of the U.S. transportation sector. The VTO Electrification Sub-Program is composed of Electric Drive Technologies, and Grid Integration activities. The Electric Drive Technologies group conducts R&D projects that advance electric motors and power electronics technologies. The Grid and Charging Infrastructure group conducts R&D projects that advance grid modernization and electric vehicle charging technologies. This document presents a brief overview of the Electrification Sub-Program and progress reports for its R&D projects. Each of the progress reports provide a project overview and highlights of the technical results that were accomplished in FY 2019.
25 ENERGY STORAGE↗
DC current controller for continuously variable series reactor
A direct current controller includes a rectifier configured to convert alternating current input into a direct current output. A converter electrically coupled to the rectifier generates a converted direct current voltage that regulates a converted direct current from the direct current output of the rectifier and synthesizes an ac component of an alternating current grid to counteract an induced back-emf. A direct current controller central controller coupled to the converter regulates the converted direct current.
Wang, Fei (Fred)↗
Load Power Agnostic 6.6 kW Wireless EV Charger with LCL Tuned Primary and Secondary Side Regulation
Wireless charging of electric vehicles (EVs) is going to play a major role in electrification of transportation. This paper proposes to utilize an LCL tuned primary and series tuned secondary with a secondary buck regulator to achieve power transfer control by secondary side control only. Analytical expressions for base (primary) coil current and transformer turns ratio N required to transfer the required power at a certain input voltage is calculated for a given coil set. The required parameters are calculated for a 6.6 kW wireless charging system with a matched circular coil set. The proposed control scheme and analysis were validated through Saber Sketch simulations and by a 6.6 kW laboratory prototype. Experimental results for different load power settings at voltages of 290 V, 340 V, and 370 V are presented.
Galigekere, Veda Prakash N.↗
A Review of High-Power Wireless Power Transfer
High-power wireless power transfer (HPWPT) is a key enabling technology for the adoption of battery electric vehicles (BEVs). As the technology has matured from year to year, discussions of standardization and many commercial partners have come to the area. Much research has been done in this area, and the realization of high-power charging has been furthered by the introduction of new techniques and devices. Here, current high-power WPT systems are reviewed and the passive elements, devices, subsystems, and techniques that have been developed to reach high-power levels are briefly detailed.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Guest Editorial Special Issue on Wireless Charging Systems
Wireless power transfer is a safe and convenient method for electric vehicle (EV) charging. And, if designed properly, it can be highly efficient. Applications cover a wide range of power transfer levels from less than a kilowatt to a few hundreds of kilowatts with transfer distances from a few millimeters to a few hundreds of millimeters. Applications also cover stationary, dynamic (in-motion), or quasi dynamic wireless charging systems. Safety is inherent in wireless power transfer systems due to the large airgap separation between the source and load sides, and users do not have to touch any cables, connectors, or plugs at all. With the recent advancements in automation, parking aid systems can be integrated and the wireless charging process can be a simple “park and go” approach without requiring any input from the driver.When applied in motion, wireless charging can be the ultimate end of game in transportation electrification, providing reduced battery size and cost with unlimited range for EVs. This approach is also known as ”charge-on-the-go” or “roadway powered vehicle” concept. While the connected and automated vehicles can self-drive and self-park, they currently cannot self-charge. Furthermore, wireless charging is a key enabling technology for the widespread development and adoption of connected and automated vehicle technology for the future of smart mobility.
33 ADVANCED PROPULSION SYSTEMS↗
Overvoltage protection system for wireless power transfer systems
A wireless power transfer overvoltage protection system is provided. The system includes a resonant receiving circuit. The resonant receiving circuit includes an inductor, a resonant capacitor and a first switching device. The first switching device is connected the ends of the inductor. The first switching device has a first state in which the ends of the inductor are electrically coupled to each other through the first switching device, and a second state in which the inductor and resonant capacitor are capable of resonating. The system further includes a control module configured to control the first switching device to switching between the first state and the second state when the resonant receiving circuit is charging a load and a preset condition is satisfied and otherwise, the first switching device is maintained in the first state.
24 POWER TRANSMISSION AND DISTRIBUTION↗