Grid-Forming Inverter Patents: Leaders, Trends & White Space 2026
- Filing peaked in 2022 at 28 families and has not been exceeded since, with the most recent full year running below that mark — a sign the initial land grab on core control methods is already behind most filers.
- China dominates the filing venue with 29 receiving-office filings against 20 in the United States and 11 at the EPO, so freedom-to-operate work has to start with Chinese fault-current and short-circuit-ride-through art.
- The most-cited records are almost all fault-current limiting methods for grid-forming converters under short-circuit conditions — not steady-state control — which tells you where the defensible prior art is actually concentrated.
Filing growth compares 2021 (6 records) with 2024 (18) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 77 records in scope (CR5), not by the ranked leaders only.
What the grid-forming inverter patent record actually covers
Grid-forming inverter design sits at the intersection of power conversion hardware and grid-stability control theory. The search underlying this landscape combines virtual synchronous machine, droop control, and grid-forming control language in the claims and title with an IPC footprint centred on H02M7 (power conversion), H02J3/38 (parallel feeding of AC networks) and H02M1/00 (apparatus for control of conversion). That combination captures both the converter topology side of the problem and the control-loop side that makes an inverter behave like a synchronous generator rather than a passive current source.
77 patent families published between 2015 and mid-2026 make up this dataset, with publication for the most recent year understated because grants and applications typically surface roughly 18 months after filing. The technology composition skews heavily toward grid systems and power conversion classes, with a smaller but consistent presence in wind turbine control, motor/generator control, and protective circuitry — a footprint consistent with grid-forming control being developed primarily for renewable generation assets that need to support grid frequency and voltage without a rotating mass.
Filing trend and technology composition
Two views of the same 77-family dataset: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing rose sharply into 2022, then flattened
Filings moved from zero in 2017 to a peak of 28 in 2022, the dataset's midpoint year. Activity since has not exceeded that peak, and the most recent year is still partial — so a flat-looking curve is not yet evidence of decline, only of a maturing first wave of filings around core control methods.
H02J and H02M carry almost all of the claim volume
H02J (power supply and grid systems) appears in 74 of 77 records and H02M (power conversion) in 29, confirming this is fundamentally a grid-integration and converter-control field. Wind turbine control (F03D, 9 records) and motor/generator control (H02P, 6) are the largest adjacent classes, with protective circuitry (H02H, 5) and welding/soldering (B23K, 3) appearing only incidentally.
Shares are the percentage of the 77 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Grid-Forming Inverter Inverter Design with Eureka
This page is one run against one query. Ask Eureka your own question about grid-forming inverter inverter design and every answer comes back with the patent numbers behind it.
Try EurekaThe claims other filers cite most
WO2023117004A1 — Generator power peak limiting in virtual synchronous machine wind turbine
The invention relates to a method for limiting generator loads in a wind turbine comprising a power converter with a line side inverter configured as a grid forming inverter. The method comprises determining a maximum grid current value (Imax) based on a measured generator load (Lgen) and a limit function which sets an upper maximum grid current value (Imax-H) and a lower maximum grid current value (Imax-L) so that the maximum grid current value approaches the lower maximum current value if the generator load is greater than a maximum generator load and approaches the upper maximum current value if the generator load is small.Filed by Vestas Wind Systems A/S, published 2023-06-29.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20230411965A1 | System-level overload ride-through control strategy for grid-forming inverter-based resources | 19 |
| 2 | CN114050561A | 限制对称短路故障下构网型变流器过电流的方法及系统 | 19 |
| 3 | CN116316805A | 电网故障下构网型逆变器动态限流控制方法 | 18 |
| 4 | CN118117651A | 基于并网模式切换的构网型逆变器的低压故障电流限幅方法 | 17 |
| 5 | CN117277414A | 一种基于虚拟电阻的构网型变流器预同步控制方法及系统 | 15 |
| 6 | US20230369865A1 | Virtual impedance current limiting control for grid forming inverter-based resources | 15 |
| 7 | US20230031575A1 | System and method for power control of an inverter-based resource with a grid-forming converter | 7 |
| 8 | CN119891342A | 基于功率匹配的构网型柔直系统限流方法、系统及设备 | 6 |
| 9 | CN119010198A | 一种构网型逆变器并联运行控制方法及系统 | 6 |
| 10 | WO2023117004A1 | Generator power peak limiting in virtual synchronous machine wind turbine | 6 |
Citation counts reflect influence within this searched corpus and favour older filings; a low count on a recent family does not mean the claim is weak, only that it has had less time to accumulate citations.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns in the data change how a competitive-intelligence or IP team should read this field.
The first wave of core control claims has already crested
Filing rose from nothing in 2017 to 28 families in 2022 and has not matched that since, even accounting for publication lag. That pattern is typical of a control-method land grab that front-loaded the broad claims early, leaving later filers to compete for narrower, more specific improvements.
China is the primary filing venue, not a secondary one
China accounts for more receiving-office filings than the United States and Europe combined against the next two venues, and the most-cited records in the dataset are predominantly Chinese fault-current-limiting methods. Any freedom-to-operate search that starts with USPTO or EPO prior art alone will miss the densest claim territory.
Fault-current limiting under short-circuit conditions is the most-defended sub-area
Nearly every heavily-cited record in this dataset addresses limiting overcurrent or dynamic current under grid fault conditions for grid-forming converters, rather than steady-state droop or virtual-inertia control. That concentration signals where the strongest prior art blocking positions already exist.
Several established filers show no latest-year activity
Assignees including large equipment makers and a major research institute show zero filings in the most recent tracked year, with one showing a full year-over-year drop. That could reflect a pause in new claim territory, a shift to trade secret protection, or simply publication lag masking work already filed.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to grid-forming inverter inverter design, with the prior art for and against each one.
Assignee landscape and collaboration patterns
Filing in this dataset clusters around a small set of Chinese grid-operator research institutes and a handful of global wind and power-conversion equipment makers, with co-filing patterns that mirror institutional structure rather than open collaboration.
State Grid entities co-file within their own institutional structure
The strongest co-assignee pairs in the dataset all involve State Grid Corporation of China and its provincial or research-institute affiliates, each pair appearing twice. This pattern reflects internal collaboration across a state utility's research network rather than cross-company joint development.
Wind and power-conversion majors filed early, then went quiet
General Electric, its renewable-energy Spanish subsidiary, Vestas, and Battelle Memorial Institute all show zero filings in the most recent tracked year in this dataset. Their earlier filings, including the representative Vestas record on generator power peak limiting, suggest the initial control-method claims are already staked.
University filers show sharp swings rather than steady output
Huazhong University of Science and Technology shows a full year-over-year drop to zero in the latest tracked year, a pattern more typical of grant-cycle-driven academic filing than of a sustained commercial program. Shandong University appears in the dataset without the same momentum data reported.
| Assignee | Recent year | YoY |
|---|---|---|
| General Electric Company | 0 | — |
| General Electric Renewable Energy Spain, S.L. | 0 | — |
| Vestas Wind Systems A/S | 0 | — |
| Battelle Memorial Institute | 0 | — |
| Huazhong University of Science and Technology | 0 | -100% |
| State Grid Corporation of China | 0 | — |
| SIEMENS CORP | 0 | — |
| Hitachi Energy Ltd. | 0 | — |
Where to take this analysis
This landscape identifies the pattern; the next step is testing a specific claim or design against it.
Check a draft claim against the fault-current cluster
The most-cited records concentrate on limiting overcurrent under short-circuit conditions for grid-forming converters. Before filing in this area, run a targeted novelty check against that specific cluster rather than the field broadly.
Search prior art in EurekaTrack assignee filing momentum over time
Several major equipment makers show no filings in the most recent tracked year. Set up ongoing monitoring to catch when they resume, or when a new entrant fills the gap.
Monitor assignees in EurekaExplore the under-claimed branches
Black-start sequencing, multi-inverter synchronization, and weak-grid virtual inertia tuning show low filing density relative to the core control claims. Map the existing art there before committing R&D budget.
Explore white space in EurekaCommon questions on grid-forming inverter patents
A grid-forming inverter sets its own voltage and frequency reference and behaves like a synchronous generator, rather than tracking an existing grid signal the way a grid-following inverter does. This dataset's IPC composition, concentrated in H02J power-grid classes and H02M power-conversion classes, reflects that grid-forming patents skew toward control methods for maintaining stability and limiting fault current, while grid-following patents more often focus on synchronization and power quality. Filing in the grid-forming space only began accelerating after 2017 as renewable generation created demand for inverters that could support grid stability without rotating mass.
The dataset shows filing concentrated among Chinese state-grid-affiliated research institutes and a small group of global wind and power-conversion equipment makers, including General Electric, its renewable-energy Spanish subsidiary, Vestas, and Battelle Memorial Institute. Several of these established filers show zero filings in the most recent tracked year, which may indicate a pause in new claim territory or simply reflect the roughly 18-month lag between filing and publication. State Grid entities co-file heavily within their own institutional network, appearing in three of the six identified co-assignee pairs.
China is the largest receiving office in this dataset with 29 filings, ahead of the United States at 20 and the EPO at 11, so a filing strategy that skips Chinese prior art risks missing the densest claim territory, particularly around fault-current limiting methods. India and WIPO PCT filings are smaller but present, suggesting some filers are pursuing broader international coverage. The right venue mix depends on where the underlying hardware or grid asset will actually be deployed, since grid-code compliance claims are jurisdiction-specific by nature.
Fault-current limiting under short-circuit conditions is the most heavily cited sub-area in this dataset, with the top-cited records almost all addressing how a grid-forming converter limits overcurrent during a grid fault. Broader control topics like virtual synchronous machine behavior and droop control are well represented across the 77 families but show more distributed citation patterns. Adjacent branches such as black-start sequencing, multi-inverter synchronization during islanding, and protective coordination between grid-forming and grid-following units show comparatively low filing density.
Filing peaked at 28 families in 2022 and has not exceeded that level since, with the most recent tracked year still partial due to publication lag. This looks more like a maturing field than a still-accelerating one, though it is too early to call it declining since a full year of 2026 filings has not yet published. Recent-year momentum data showing several major assignees at zero filings supports the read that the initial broad control-claim land grab has largely concluded, even as narrower improvement claims likely continue.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.