String Inverter Safety Patents: Who Leads, Where Gaps Remain 2026
- Filing peaked in 2025 at 40 records after a flat-to-declining run through the 2022 midpoint (24), suggesting the field is consolidating around known architectures rather than expanding into new ones.
- H02J and H02S dominate the composition with 123 and 87 records respectively, while adjacent subclasses like G05F (20) and B60L (19) show comparatively thin coverage.
- The US receiving office carries the bulk of filings at 119 of 207 records, more than double the EPO's 44, pointing to where enforcement risk concentrates first.
Filing growth compares 2021 (16 records) with 2024 (35) — 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 207 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 207 patent families filed between 2015 and 2026 that combine string or PV solar inverter hardware with arc-fault protection, rapid shutdown, or grid safety compliance claims. The search string deliberately pairs power-conversion hardware terms with safety-function terms, so the corpus captures the specific intersection where UL 1699B and NEC 690.12 rapid-shutdown requirements meet inverter design, rather than solar power generation broadly.
Publication lags filing by roughly eighteen months, so the 2026 count of 2 and even the 2025 count of 40 understate the true recent filing rate. Read the trend's shape, not its most recent point.
Filing trend and technology composition
Two views of the same 207 families: how filing activity has moved year over year, and which IPC subclasses carry the claim density.
A flat-to-declining trend after a 2025 peak
Filings rose from 7 in 2017 to a peak of 40 in 2025, but the 2022 midpoint of 24 sits well below a straight-line extrapolation from either end, indicating the growth curve flattened mid-period before the late run-up. Treat 2025 and 2026 as provisional given publication lag.
Concentration in grid and PV subclasses
H02J (power supply and grid systems) and H02S (photovoltaic generation) together account for 210 of the tagged classifications, well ahead of H02M power conversion (36) and H02H protective circuits (31). Measurement (G01R, 26) and control (G05F, 20) subclasses trail further, and EV propulsion (B60L, 19) appears only as a secondary tag on inverter families with shared power-electronics architecture.
Shares are the percentage of the 207 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on String Inverter Safety and Compliance with Eureka
This page is one run against one query. Ask Eureka your own question about string inverter safety and compliance and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this corpus
Rapid shutdown device for photovoltaic modules (US11811361B1)
A rapid shutdown device for rapidly de-energizing a photovoltaic module system is disclosed. The rapid shutdown device includes power lines connected to a photovoltaic string of modules on a roof of a structure. A high voltage switch on a first power line is disconnected when the high voltage switch is open. The rapid shutdown device includes a gate drive circuit that receives an electronic photovoltaic string status signal associated with an operating status of the photovoltaic string. The gate drive circuit may determine that the operating status indicates the presence of a hazard based on the electronic photovoltaic string status signal.Filed by GAF Energy LLC, granted 2023-11-07.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20160329715A1 | Photovoltaic power system inverter detection | 124 |
| 2 | US20180191292A1 | Method and system for communication between inverter and solar module | 88 |
| 3 | US11811361B1 | Rapid shutdown device for photovoltaic modules | 52 |
| 4 | US20200336003A1 | Energy control system | 45 |
| 5 | US20160344192A1 | Systems and methods for quick dissipation of stored energy from input capacitors of power inverters | 33 |
| 6 | US20190027617A1 | Photovoltaic panel rapid shutdown and recovery | 30 |
| 7 | US20220396167A1 | Electric vehicle solar charging system | 27 |
| 8 | US20210376613A1 | Microgrid system controller for creating and maintaining a microgrid | 26 |
| 9 | US20190081458A1 | Electrical Service Adapter for Supply Side Interconnect | 24 |
| 10 | US20210143774A1 | Optimizing hybrid inverter system | 21 |
Citation counts are drawn from within this searched corpus and skew toward older filings that have had more time to accumulate citations; treat them as a signal of influence rather than current relevance.
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 that matter more than the raw counts.
Growth is not linear
The jump from a flat mid-period to a 2025 peak suggests a late wave of filings, likely tied to tightening rapid-shutdown code cycles, rather than sustained organic growth in the field.
US filings dominate enforcement exposure
With more than half of all records routed through the US receiving office, freedom-to-operate risk for rapid-shutdown hardware sold into the US market is the first thing to clear before entering that market.
Grid-safety claims outweigh PV-specific claims
H02J's lead over H02S implies that much of the claim activity centres on grid-interface safety functions common to any inverter, not PV-specific rapid-shutdown mechanics alone.
A small inventor cluster drives repeat filings
The strongest co-assignee pairs each recur at six shared filings, all involving the same lead inventor, indicating a concentrated internal team rather than broad cross-company collaboration.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to string inverter safety and compliance, with the prior art for and against each one.
Who is filing, and where activity has stalled
Recent-year momentum data shows several previously active assignees dropping to zero filings in the latest year, which is as informative as who is still filing.
Several named assignees have gone quiet
A number of assignees tracked in the momentum data, including firms with prior activity, show zero filings in the most recent year and year-over-year declines of -100% where a prior baseline existed.
Early rapid-shutdown detection art anchors the field
The most-cited record, on photovoltaic power system inverter detection, and the second-ranked communication-protocol filing together set much of the vocabulary later filings build on or design around.
Collaboration is limited and inventor-driven
The co-assignee network is thin: ten pairs total, with the strongest links all tracing to the same lead inventor working across several named co-inventors rather than to inter-company joint filings.
| Assignee | Recent year | YoY |
|---|---|---|
| Hanwha Solutions Corporation | 0 | -100% |
| SunPower Corporation | 0 | — |
| dcbel Inc. | 0 | — |
| Diego Energy Ltd. | 0 | -100% |
| Eaton Intelligent Power Limited | 0 | — |
| Maximum Output Renewable Energy Company | 0 | — |
| SolarEdge Technologies Ltd. | 0 | — |
| MCCUNE CHUCK | 0 | — |
Where to take this analysis
The dataset points to specific next steps rather than a single conclusion.
Clear freedom-to-operate against the top-cited records
The five most-cited records, particularly the two filed before 2018, set claim boundaries that later filings still work around; check any new rapid-shutdown design against them first.
Explore citation network in EurekaWatch the 2025-2026 filing gap close
Publication lag means the apparent 2025 peak and 2026 drop are not yet final; revisit the trend once later filings publish to see whether the peak holds.
Track filing trends in EurekaAssess the under-claimed measurement and switchboard branches
G01R and H02B carry meaningfully lower record counts than the core grid and PV subclasses, which may indicate open claim space for diagnostic or substation-level compliance integration.
Search white space in EurekaCommon questions on string inverter safety patents
This landscape includes patent families that combine string or PV solar inverter hardware claims with arc-fault protection, rapid shutdown, or grid safety compliance functionality. It excludes general solar power generation patents that do not touch on these specific safety functions. The 207 records span IPC subclasses from power supply systems (H02J) through protective circuits (H02H) and measurement (G01R), reflecting how broadly rapid-shutdown compliance now touches inverter design.
The data shows a midpoint of 24 filings in 2022 against a peak of 40 in 2025, which is not a straight-line growth curve. This pattern is consistent with a late wave of filings likely driven by tightening code requirements such as NEC 690.12 rapid-shutdown mandates rather than continuous organic expansion. Because publication lags filing by roughly eighteen months, the apparent 2026 drop to 2 records is largely an artefact of unpublished applications, not a real collapse in activity.
The United States receiving office accounts for 119 of the 207 records, more than double the European Patent Office's 44 and far ahead of WIPO PCT filings at 16. Anyone shipping rapid-shutdown or arc-fault hardware into the US market should treat US claim clearance as the priority, since that is where both filing density and, presumably, enforcement activity concentrate. Europe and India carry meaningfully thinner coverage by comparison.
US11811361B1, assigned to GAF Energy and granted in 2023, claims a rapid shutdown device architecture that de-energizes a photovoltaic string using a high-voltage switch controlled by a gate drive circuit responding to an electronic string status signal. It sits within a corpus where the two highest-cited records (124 and 88 citations respectively) already established core detection and communication concepts, so this patent's practical scope should be assessed against those earlier records as well as read on its own claims. Anyone designing a rooftop rapid-shutdown mechanism with string-status-driven switching should review its independent claims specifically before finalising a design.
Relative to the dense H02J and H02S clusters (123 and 87 records), subclasses like G05F control (20), B60L EV propulsion overlap (19) and H02B switchboard integration (17) carry noticeably thinner coverage. This suggests less-claimed territory in diagnostic control loops, shared EV-inverter safety architectures, and substation-level compliance integration. These are not guaranteed gaps, but the lower record density relative to the core clusters makes them worth a focused prior-art search before committing claim language.
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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.