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Wireless Power Transfer for Light-Duty Plug-In/Electric Vehicles and Alignment Methodology
- Ground Vehicle Standard
- J2954_201711
- Revised
Downloadable datasets available
Annotation ability available
Sector:
Issuing Committee:
Language:
English
Scope
The SAE Recommended Practice J2954 establishes an industry-wide specification that defines acceptable criteria for interoperability, electromagnetic compatibility, EMF, minimum performance, safety and testing for wireless charging of light duty electric and plug-in electric vehicles. The current version addresses unidirectional charging, from grid to vehicle, but bidirectional energy transfer may be evaluated for a future standard. The specification defines various charging levels that are based on the levels defined for SAE J1772 conductive AC charge levels 1, 2, and 3 with some variations. A standard for wireless power transfer (WPT) based on these charge levels will enable selection of a charging rate based on vehicle requirements, thus allowing for better vehicle packaging, and ease of customer use. The specification supports home (private) charging and public wireless charging.
In the near term, vehicles that are capable to be charged wirelessly under Recommended Practice should also be able to be charged by SAE J1772 plug in chargers.
This Recommended Practice is planned to be standardized after the 2018 timeframe after receiving vehicle data. The contents, including frequency, parameters, specifications, procedures and other contents of this Recommended Practice are to be re-evaluated at that time to allow for additional developments and future innovations.
SAE Recommended Practice J2954 is intended to be used for stationary applications (charging while vehicle is not in motion). Dynamic applications may be considered in the future based on industry feedback. This document covers above-ground surface mounted GAs. Flush mounted reference designs have been proposed in the taskforce and it is anticipated that these will be specified in the next version of the Recommended Practice planned for publication in 2018.
SAE Recommended Practice J2954 is meant to be used for interoperability, performance and emissions testing, where a single standard coil-set has been chosen for the WPT Power Class 1 and 2 to 7.7kW, per Z-Classes (1 through 3) which is circular topology. However, there are two reference options for WPT 3 to 11kW per Z-classes (1 through 3) with two topologies. The next revision of the Recommended Practice in 2018 is slated to have one standard coil set for WPT 3. This SAE J2954 Test Station is meant to provide a baseline where compatibility with the content of the Recommended Practices is to be demonstrated.
The future standard, will use this -performance based- J2954 Standard Testing Station to establish a uniform way to demonstrate design for both the electrified vehicle (VA) and WEVSE (GA) components safety, interoperability, performance and EM emissions -through testing-. The goal is to have a common methodology to validate Wireless Power Transfer and Alignment, production designs between different power classes and topologies for both the vehicle and infrastructure.
Rationale
Electrified powertrains, specifically Battery Electric and Plug-In Electric (BEV/PHEV) vehicles are projected internationally to become more prevalent in production due to environmental factors (such as CO2 emissions), regulations (such as the Greenhouse Gas and the California ZEV Mandate) and the increasing price of fossil fuels. The main benefits of electrified powertrains are eliminating or significantly reducing local emissions while increasing the overall well-to-wheels efficiency. In addition, autonomous vehicles are soon to be more commonplace to allow more convenient and safer transportation especially in traffic settings and long-distance driving.
Standardized Wireless Power Transfer (WPT) through wireless charging allows the BEV/PHEV customer an automated and more convenient and alternative to plug-in (conductive) charging. Essentially the customer simply needs to park into a SAE J2954 compatible parking space in order to charge the vehicle. WPT offers the additional advantage to autonomous vehicles enabling autonomous parking with alignment assistance and automated charging (in all weather conditions such as rain or snow).
It is essential that data-based standards are used as a basis for commercialization of this technology. The SAE J2954 TF has documented the lessons learned from the first stage of testing with real OEM systems. The SAE J2954 Recommended Practice will be an evolution of the TIR J2954 based on interoperability data.
Recommended Content
| Ground Vehicle Standard | Recommended Practice for General Fuel Cell Vehicle Safety |
| Ground Vehicle Standard | Wireless Power Transfer for Light-Duty Plug-in/Electric Vehicles and Alignment Methodology |
| Ground Vehicle Standard | Recommended Practice for the Design and Test of Hybrid Electric and Electric Trucks and Buses for Electrical Safety |
Topic
Data Sets - Support Documents
| Title | Description | Download |
|---|---|---|
| Unnamed Dataset 1 | ||
| Unnamed Dataset 2 | ||
| Unnamed Dataset 3 | ||
| Unnamed Dataset 4 | ||
| Unnamed Dataset 5 | ||
| Unnamed Dataset 6 | ||
| Unnamed Dataset 7 | ||
| Table 1 | WPT power classifications for L.D. vehicles | |
| Table 2 | Interoperability by Power Class | |
| Table 3 | Specification of the Z-classes | |
| Table 4 | Compatibility between Z class GAs and VAs | |
| Table 6 | Positioning tolerance requirements for Test Stand VAs and Product VAs | |
| Unnamed Dataset 13 | ||
| Table 7 | Component level EMC - off-board components | |
| Unnamed Dataset 15 | ||
| Table 8 | EMF exposure standard: Reference levels | |
| Table 12 | Reference EMF exposure measurement standards | |
| Table 13 | Example worksheet for worst case operating condition search | |
| Table 14 | Touch current measurement points | |
| Table 15 | Coupler configurations for touch current measurement | |
| Table 16 | Combined EMF and pacemaker limits for laboratory use | |
| Table 17 | Measurements of fields | |
| Table 18 | “Natural offset” (x_0) for the systems as described in the Appendixes of this document | |
| Table 19 | Test configurations | |
| Table 20 | Maximum rotational offsets | |
| Table 21 | Offset positions for testing | |
| Table 22 | Sample efficiency test form | |
| Table 23 | Table of test objects | |
| Table A1 | Inductance | |
| Table A2 | Inductance | |
| Table A3 | Inductance | |
| Table A4 | Secondary coil inductance L and impedance matching values | |
| Table A5 | Secondary coil inductance L and impedance matching values | |
| Table A6 | Secondary coil inductance L and impedance matching values | |
| Table B2 | Secondary coil inductance L2 and secondary tuning capacitor C | |
| Table B4 | Secondary coil inductance L2 and secondary tuning capacitor C | |
| Table B6 | Secondary coil inductance L2 and secondary tuning capacitor C | |
| Table C1 | Maximum values of currents | |
| Table C2 | Primary coil inductance L1 depending on the Z class | |
| Table C3 | Coupling k between primary and secondary coil depending on the Z class | |
| Table C4 | Table of values | |
| Table C5 | Primary coil inductance L depending on the Z class | |
| Table C6 | Coupling k between primary and secondary coil depending on the Z class | |
| Table D2 | Primary coil inductance L1 depending on the Z class | |
| Table D3 | Coupling k between primary and secondary coil depending on the Z class | |
| Table E1 | Primary coil inductance L depending on the Z class | |
| Table E2 | Maximum currents in the GA WPT3 | |
| Table E3 | Coupling k between primary and secondary coil depending on the Z class | |
| Table E5 | Secondary coil inductance L | |
| Table E7 | Secondary coil inductance L | |
| Table 9 | Secondary coil inductance L | |
| Table E14 | Primary coil inductance L1 depending on the air gap class | |
| Table E15 | Coupling k between primary and secondary coil depending on the air gap class | |
| Table E16 | Secondary coil inductance L2 depending on the air gap class | |
| Table E17 | Secondary tuning capacitor C depending on the air gap class | |
| Table G1 | Secondary impedance Z for fixed power level and varying output voltage U . | |
| Table G2 | Calculation of Z impedance for fixed power level and varying output voltage U . | |
| Table G3 | Calculation of Z impedance including tolerance factor for fixed power level and varying output voltage U | |
| Table H1 | Magnetic flux and voltage values for the Z1 transversal | |
| Table H2 | Magnetic flux and voltage values for the transversal test device | |
| Table H3 | Magnetic flux and voltage values for the transversal test device | |
| Table H1 | Magnetic flux and voltage values for Z1 coaxial | |
| Table H5 | Magnetic flux and voltage values for Z2 coaxial | |
| Table H6 | Magnetic flux and voltage values for Z3 coaxial | |
| Table L1 | Approximate impact on VA of varying k based on design and chosen operation | |
| Table L2 | Approximate pad losses assuming Q = Q = 400, with two values of k and variations in primary and secondary operating Q | |
| Unnamed Dataset 67 | ||
| Table O1 | ||
| Table O2 | ||
| Table P1 | Methods of EMI measurement |
Issuing Committee
The Hybrid Technical Standards Committee reports to the Powertrain Systems Group of the Motor Vehicle Council. The Committee is responsible for developing and maintaining SAE Standards, Recommended Practices, and Information Reports related to the field of hybrid vehicle technology. The following topics are within the scope of this committee's work: safety aspects of hybrid systems in vehicles, test procedures to establish the performance of hybrid systems and components, nomenclature, as well as vehicle interface and serviceability requirements Participants in the SAE Hybrid Technical Standards Committee include OEMs, suppliers, consulting firms, government, and other interested parties.
Reference
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