Conductive power and energy transfer systems for electric vehicles - Part 21-1: Electric vehicle on-board charger EMC requirements for conductive connection to AC/DC supply

This Final Draft International Standard is an up to 6 weeks' pre-release of the official publication. It is available for sale during its voting period: 2026-06-19 to 2026-07-31. By purchasing this FDIS now, you will automatically receive, in addition, the final publication. IEC 61851-21-1:2026 covers electromagnetic compatibility (EMC) requirements for conductive connection of an electric vehicle (EV) to an AC or DC supply. It applies only to on-board charging systems either tested on a host vehicle or tested on the charging system component level (ESA – electronic sub assembly). This document does not set any requirements for the vehicle as a whole when the on-board charger (OBC) is tested on host vehicle level. Vehicle requirements are defined for example in CISPR 12 or the ISO 11451 series. This document is also useful for industrial trucks and vehicles designed primarily to be used off-road, for example forestry and construction machines, in charging mode. This document is not applicable to trolley buses and rail vehicles. Bidirectional power transfer between the EV rechargeable energy storage system (RESS) and the grid (for vehicle to grid in grid-following mode) or a load/islanded installation (for vehicle to load or home in grid-forming mode) will be dedicatedly treated in a future edition of IEC 61851-21-1. Until then, host vehicles in grid-following mode are treated as an additional operating mode for emission requirements and the same requirements apply. This second edition cancels and replaces the first edition published in 2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Clause 1: The Scope has been defined more precisely; b) Clause 2: Normative references have been updated; c) Clause 3: Some definitions have been added; d) Clause 4: A bidirectional charging mode has been added; e) Clause 5: The test setup for vehicle in charging mode has been described more precisely and the figures and their keys have been updated. In Tables 2 & 3 pulse modulation testing has been added. The frequency range has been extended down to 9 kHz for conducted emission measurements and up to 6 GHz for radiated emission and immunity measurements. Additionally, the emission test operating conditions have been defined more precisely. f) Annex A (normative): DC-charging-AN has been defined more precisely; g) Annex B (informative) has been added; h) Annex C (informative) has been added; i) Annex D (informative) on future work items has been added.