Technology page · data to 2026-10-15
Rare-earth-free electric motor patents
If your team works on this technology, the risk is building next to a competitor's claim you have not read yet, often published only in Chinese, Japanese or Korean.
Free: the latest weekly issue on this and the other rare-earth-free magnet technologies, one plain-English entry per invention.
Motor designs that avoid rare-earth magnets: synchronous reluctance and magnet-assisted reluctance rotors, switched reluctance, wound-field and ferrite-based machines. Filings cover rotor geometry, flux barriers, windings and control.
In our base
- 999 patent families (1479 publications) published from 2021-09-27 to 2026-10-15.
- 159 new families in the last twelve months, against 171 in the twelve months before.
New families by year of first publication
* 2021 counts publications from 09-27, when our base starts.
* 2026 counts publications up to 10-15 only; new publications reach our sources weeks late, Chinese ones three weeks or more.
| Year | Families |
|---|---|
| 2021 | 59 |
| 2022 | 276 |
| 2023 | 163 |
| 2024 | 225 |
| 2025 | 142 |
| 2026 (to 10-15) | 134 |
Offices
A family counts once in each office where a member has published.
| Office | Families |
|---|---|
| CN | 780 |
| WO | 136 |
| US | 131 |
| EP | 91 |
| KR | 27 |
| JP | 24 |
| DE | 19 |
| TW | 8 |
| GB | 4 |
| MX | 2 |
| CA | 1 |
| CZ | 1 |
| FI | 1 |
| MY | 1 |
| SE | 1 |
Applicants with two or more families
Harmonised names from the source record; subsidiaries are not merged.
| Applicant | Families |
|---|---|
| Gree Electric Appliances Inc Zhuhai | 86 |
| Pearl Haige Electric Appliance Co Ltd | 62 |
| Mahle Int GmbH [DE] | 25 |
| Univ Huazhong Science Tech | 21 |
| Univ Jiangsu | 20 |
| Harbin Inst Technology | 19 |
| Mahle Int GmbH | 18 |
| Schaeffler Technologies AG [DE] | 18 |
| Univ Shandong | 16 |
| Audi AG | 15 |
Most recent publications
The newest publication in each of the 8 most recently active families, as recorded. Families our analysts have reviewed carry a note.
Axial-flux electric traction machine
US-20260322192-A1 · published 2026-10-15 · Valeo Electrification [FR] · offices: US, WO
Rotor, separately excited synchronous machine and motor vehicle
US-20260312469-A1 · published 2026-10-08 · Audi AG [DE] · offices: CN, DE, US
Audi's second rotor-converter family is now published in the US, after Germany and China. Here the rectifier between the secondary coil and the rotor winding is a potted assembly of two half-bridges. With family 98776004, Audi is building a position on contactless rotor excitation.
Triple Stator Homopolar Alternator
US-20260312453-A1 · published 2026-10-08 · Niehoff & Co C E [US] · offices: US
An electrically excited syncrhonous machine EESM with a field-modulated magnetic gear and a marine propulsion unit comprising the EESM
SE-2550664-A1 · published 2026-10-02 · Volvo Penta Corp [SE] · offices: SE
Volvo Penta has a Swedish application on an EESM combined with a field-modulated magnetic gear, for marine propulsion. Our record has only the title. Such gears usually rely on permanent magnets, so whether this design avoids rare earths is open.
Current transmission device for externally excited synchronous machines having segmented ferrite cores
US-20260291300-A1 · published 2026-09-24 · ZF Friedrichshafen AG [DE] · offices: CN, US, WO
ZF claims a contactless current-transmission device for externally excited synchronous machines. Stator and rotor each carry a ferrite core, and at least one core is built from ferrite segments held in a matrix. The family also has WO and CN publications. Segmented cores make the rotary transformer easier to build at motor diameters. Schaeffler's applications on driving the same component (family 99137366) were published two weeks before ZF's US application.
Drive axle for an electric vehicle
US-20260291338-A1 · published 2026-09-24 · Zahnradfabrik Friedrichshafen [DE] · offices: CN, US, WO
Permanent magnet assisted synchronous reluctance motor
US-20260280395-A1 · published 2026-09-17 · Gree Electric Appliances Inc Zhuhai [CN] · offices: CN, EP, US, WO
US-20260280395-A1 claims a permanent-magnet-assisted synchronous reluctance motor with a deliberate offset between rotor and stator. When one rotor d-axis meets a stator tooth, the next d-axis meets a slot, and the q-axis between them sits off both. Offsets of this kind are used to reduce torque ripple and noise. The applicant is Gree Electric Appliances (Zhuhai). The family also has WO, CN and EP publications: WO-2024212585-A1, CN-116345832-A and EP-4668545-A1.
Eesm control method
US-20260280460-A1 · published 2026-09-17 · Volvo Truck Corp [SE] · offices: US
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Publications come from the EPO Open Patent Services and Google Patents Public Data, matched against a published CPC and keyword scope and grouped by DOCDB patent family. New publications reach our sources several weeks after they are published (Chinese ones three weeks or more), so the latest weeks are incomplete.