Static Var Generator Patents: Who Leads, Where the Gaps Are 2026
- 60.2% of all 118 records sit with the top five assignees combined, and the leader alone holds 27 — this is a concentrated field, not a fragmented one.
- Filing peaked in 2017 at 9 and had fallen to a 2022 midpoint of 3, with the most recent year understated by publication lag — momentum is flat to declining, not growing.
- G05F variable control appears in 25.4% of records alongside universal H02J coverage, while wind-integration classes like F03D sit under 6% — a narrower band than the topic name suggests.
What this patent set covers
This landscape tracks patent families published between 2015 and 2026 that combine static var generator, STATCOM, or reactive power compensation device terminology in the title with claim language on response time, harmonic filtering, unbalanced load compensation, cascaded H-bridge topology, or grid voltage support, restricted to IPC classes H02J3, H02M7 and H02M1. The scope is deliberately narrow: it is not every reactive-power patent, but the subset where the claims speak directly to dynamic compensation performance rather than generic power conversion.
118 records meet that definition. Filing offices skew toward China and the United States, with Canada, WIPO, Australia and Europe filling out the remainder — a pattern consistent with grid operators and equipment makers protecting core markets plus a PCT filter for global reach.
Trend and technology composition
Two views of the same 118 records: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend, 2017–2026
Filings peaked at 9 in 2017 and eased to a 2022 midpoint of 3, with the 2026 figure necessarily incomplete since publication typically lags filing by around 18 months. The shape reads as a mature, saturated claim space rather than an emerging one — later filers are working around, not into, open ground.
IPC subclass distribution
Every record in scope carries an H02J classification by construction, and a quarter also carry G05F for variable electric or magnetic control — the pairing that defines core STATCOM control-loop claims. Wind-turbine integration (F03D) and protective circuitry (H02H) each remain under 6% of records, which marks them as adjacent rather than central to this claim set. Because records can carry multiple classes, these shares are read against the full 118-record base, not against each other.
Shares are the percentage of the 118 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Static Var Generators and Reactive Compensation with Eureka
This page is one run against one query. Ask Eureka your own question about static var generators and reactive compensation and every answer comes back with the patent numbers behind it.
Try EurekaThe documents anchoring this field
US4555659A — Static VAR generator system having improved response time
A static VAR generator utilizing a multitude of reactor banks each having different computation circuits and firing angle control circuits is provided. The different computation and firing angle control circuits allow the VAR generator the flexibility of changing reactor power in an A.C. network repetitively in any cycle in response to rapid changes in load demand, accomplished by progressively longer computation times and later insertion of additional banks after the first bank has responded.Filed by ASEA BROWN BOVERI, INC. and granted in 1985, this filing predates the rest of the corpus by three decades and defines the multi-bank, staged-response architecture that later cascaded H-bridge and unbalanced-load claims still have to route around.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20050012395A1 | Integrated closed loop control method and apparatus for combined uninterruptible power supply and generator s… | 228 |
| 2 | US20050194944A1 | Dynamic reactive compensation system and method | 105 |
| 3 | US20080088183A1 | Integrated Closed Loop Control Method and Apparatus for Combined Uninterruptible Power Supply and Generator S… | 86 |
| 4 | US7091703B2 | Dynamic reactive compensation system and method | 82 |
| 5 | US7701087B2 | Integrated closed loop control method and apparatus for combined uninterruptible power supply and generator s… | 61 |
| 6 | US3999117A | Method and control apparatus for static VAR generator and compensator | 59 |
| 7 | WO2004054065A1 | Uninterruptable power supply and generator system | 44 |
| 8 | US4047097A | Apparatus and method for transient free energization and deenergization of static VAR generators | 44 |
| 9 | US20040071000A1 | Adaptive controller for d-statcom in the stationary reference frame to compensate for reactive and harmonic d… | 43 |
| 10 | US6862199B2 | Adaptive controller for d-statcom in the stationary reference frame to compensate for reactive and harmonic d… | 41 |
Citation counts favour older filings simply because they have had more time to be cited — read them as a signal of influence within this corpus, not of current commercial 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 say about this field
Four figures worth sitting with before deciding where to file next.
A small group holds most of the claim space
The top five assignees combined account for 60.2% of all 118 records in scope, and the leader alone holds 27. The top ten extend that to 72.0%. New entrants are not filing into open ground; they are filing around an already-dense core.
Filing activity is flat to declining
Activity peaked in 2017 at 9 filings and had eased to a midpoint of 3 by 2022. Even allowing for the ~18-month publication lag that understates the most recent year, the trajectory points to a settled rather than expanding field.
Control-loop claims dominate over hardware variants
A quarter of records pair H02J with G05F variable-control classification, the signature of dynamic compensation control-loop claims. Hardware-adjacent classes — power conversion, motor control, switchboards — each sit at or below 2.5% of records.
Co-filing is limited and grid-operator-led
Only 10 co-assignee pairs appear across the corpus, and the strongest recurring pairings involve a state grid operator filing alongside its own subsidiary research and software units — internal collaboration rather than cross-industry joint filing.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to static var generators and reactive compensation, with the prior art for and against each one.
Who is filing, and where the gaps sit
70 companies make up the full ranked list this dataset returns — not a top-50 or top-100 cut. Filing is led by grid-equipment and utility incumbents, with a long tail of single- or double-filing entrants below the top ten.
A single assignee holds nearly a quarter of the field
The leading assignee's 27 records alone exceed the fifth-place total several times over, setting the baseline that any competitive filing strategy in this space has to measure against.
The field thins out fast after the leader
Fifth place holds 5 records — a sharp drop from the leader's 27 — and by tenth place the count is down to 2, showing a short head and a long, thin tail rather than a smooth distribution.
Even leaders show no recent-year activity
Every one of the top-momentum assignees tracked shows zero filings in the latest year captured, consistent with the broader flat-to-declining trend rather than any single company retreating from the field.
Joint filing stays inside single organisations
The strongest co-assignee pairs pair a large grid operator with its own subsidiary research institute or software arm, suggesting internal R&D structuring drives most of the joint filings rather than external partnership.
| Assignee | Recent year | YoY |
|---|---|---|
| American Superconductor Corporation | 0 | — |
| Westinghouse Electric Corporation | 0 | — |
| Electric Power Research Institute | 0 | — |
| Vestas Wind Systems A/S | 0 | — |
| State Grid Corporation of China | 0 | — |
| Northeastern University (US) | 0 | — |
| XJ Group Corporation | 0 | — |
| Xuchang XJ Software Technology Co., Ltd. | 0 | — |
Where to take this analysis
The dataset points to specific follow-up questions rather than a single conclusion. These are the natural next moves for an R&D or IP team.
Map the leader's full claim set
With 27 of 118 records, the top assignee's portfolio is worth reading claim-by-claim before committing engineering time to the same control-loop architecture.
Explore assignee portfolios in EurekaTest the under-claimed branches
Wind-turbine integration and protective-circuit overlaps show low record counts here — confirm whether that reflects true white space or simply a narrow search scope before filing.
Run a freedom-to-operate check in EurekaWatch for the next filing cycle
Given the ~18-month publication lag, filings from 2025 onward are still incomplete in this data. Recheck the trend once later years settle.
Track filing trends in EurekaCommon questions on this landscape
The leading assignee in this dataset holds 27 of the 118 records in scope, well ahead of fifth place at 5 and tenth place at 2. The top five assignees combined account for 60.2% of all records, and the top ten reach 72.0%. That pattern means the field is concentrated at the top with a long tail of smaller filers below it, so a new entrant's freedom-to-operate work should start with the leading few portfolios rather than spreading thin across the full ranked list of 70 companies.
No, the filing trend points flat to declining. Activity peaked in 2017 at 9 filings and had eased to a midpoint of 3 by 2022. Publication typically lags filing by around 18 months, so the most recent year is always undercounted, but even accounting for that lag the multi-year trajectory does not show renewed growth. This is consistent with a technology area where core control-loop claims are already well staked out.
Every record in this dataset carries an H02J power-supply-and-grid classification by definition of the search, and a quarter also carry G05F for variable electric or magnetic control — the pairing behind most dynamic compensation control-loop claims. Smaller overlaps exist with wind turbines (F03D, 5.9% of records), electric measurement (G01R, 3.4%), and protective circuitry (H02H, 3.4%). Because a single record can carry several IPC classes, these percentages are measured against the full 118-record base and will add up to more than 100%.
US4555659A, filed by ASEA BROWN BOVERI, INC. and granted in 1985, claims a multi-bank reactor architecture where each bank carries progressively longer computation and firing-angle control circuits, staged to insert additional banks after earlier ones respond to load demand. Anyone designing a staged or tiered response mechanism for reactive compensation needs to check their architecture against this staged-insertion approach specifically, since it predates the rest of this corpus by decades and defines a response-time mechanism that later filers have had to design around rather than reuse directly.
Based on IPC composition, wind-turbine integration (F03D, 5.9% of records), protective circuit coordination (H02H, 3.4%), and electric measurement tie-ins (G01R, 3.4%) all sit well below the dominant H02J/G05F control-loop pairing. That does not guarantee open ground — it may reflect this search's narrow scope rather than true absence of prior art — but it does mark these branches as worth a dedicated freedom-to-operate search before assuming the core control-loop space is the only viable filing target.
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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.