Solid-State Transformer for EV Charging Patent Landscape
Solid-State Transformer for EV Charging Patent Landscape in 2026
The solid-state transformer for EV charging field is still expanding on a multi-year basis, though annual volume has eased from its 2023 peak; the corpus is moderately concentrated, with Delta Electronics and Hitachi Energy holding the top two positions. Power-conversion topology (H02M) dominates the technology mix, and the United States leads all filing jurisdictions.
Delta Electronics leads a moderately concentrated field
Delta Electronics (CN) holds the leading position in this landscape, followed by Hitachi Energy and Georgia Tech Research Corporation. The top five filers account for 37% of the combined output of the hundred largest filers, signalling moderate rather than extreme concentration.
A clear tier gap separates the top two applicants from the mid-tier: the leader’s count is roughly twice that of the third-ranked entity, suggesting that the two front-runners have established a meaningful head start in core power-conversion topology claims.
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 1 | Delta Electronics Inc (CN) | 21 | |
| 2 | Hitachi Energy Ltd | 17 | |
| 3 | Georgia Tech Research Corporation | 13 | |
| 4 | Delta Electronics (Shanghai) Co Ltd | 12 | |
| 5 | Huawei Digital Power Technologies Co Ltd | 11 | |
| 6 | LS Electric Co Ltd | 9 | |
| 7 | ABB E-Mobility BV | 9 | |
| 8 | ABB (Schweiz) AG | 9 | |
| 9 | UT-Battelle LLC | 8 | |
| 10 | Huawei Technologies Co Ltd | 8 |
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 11 | Multicharge OÜ | 6 | |
| 12 | McMaster University | 6 | |
| 13 | Caterpillar Inc | 5 | |
| 14 | Fronius International GmbH | 5 | |
| 15 | Hitachi Ltd | 3 | |
| 16 | Hitachi Energy Switzerland AG | 3 | |
| 17 | Delta Electronics India Pte Ltd | 3 | |
| 18 | Indian Institute of Technology | 2 | |
| 19 | Hyosung Heavy Industries Corp | 2 | |
| 20 | Mission Power Corp | 2 |
The presence of two Delta Electronics entities (Taiwan-headquartered and Shanghai-based) and two ABB entities (ABB (Schweiz) AG and ABB E-Mobility BV) in the top ten means actual corporate concentration is higher than individual entity counts imply — a point worth noting for freedom-to-operate assessments.
Filings from approximately 2024 onward are likely under-counted due to patent publication lag; apparent softening in recent data does not necessarily reflect a real slowdown in R&D activity. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Rapid post-2019 build-up with power-conversion topology dominating the mix
The annual filing trend reveals a sharp inflection point around 2020, and the technology composition chart shows that power conversion and grid integration account for the vast majority of patent activity, while transformer magnetics and protection circuits remain sparsely covered.
Annual filing trend
Filings were negligible before 2020, then surged sharply through 2021 and reached their recorded peak in 2023. The apparent dip in 2024 and 2025 should be read with caution given standard patent publication lag of 18–24 months; the three-year recent window is 75% above the prior three-year window, confirming genuine multi-year growth.
↗ Hover for values · click a bar to ask EurekaTechnology composition
H02M (power conversion) is the dominant branch by a wide margin, reflecting the centrality of converter topology design to this field. H02J (power supply and grid systems) and B60L (EV propulsion) form a secondary tier. Branches covering transformer magnetics (H01F), protection circuits (H02H), and measurement (G01R) each represent only a small fraction of total activity, identifying them as relatively under-served areas.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Power Conversion System
A power conversion system includes a high voltage (HV) switchgear; a solid-state transformer; and a low voltage (LV) switchgear. The HV switchgear connects to and disconnects from a HV or medium voltage (MV) network. The HV switchgear connects to an input of the solid-state transformer. The solid-state transformer comprises a first module and a second… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | Wireless power system | 58 |
| 2 | 一种基于固态变压器的电动汽车充电站供电系统 | 30 |
| 3 | Power apparatus applied in solid state transformer… | 18 |
| 4 | SST System with Multiple LVDC Outputs | 10 |
| 5 | Converter Topologies for AC-to-AC and AC-to-DC Pow… | 9 |
| 6 | Dual-active bridge converter and applications of s… | 8 |
| 7 | Power conversion system applied to solid state tra… | 8 |
| 8 | A system and method for supplying ac driving volta… | 8 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the competitive structure means for R&D investment decisions
The landscape’s growth trajectory, moderate concentration, and lopsided technology mix create both risk and opportunity for new entrants and incumbents alike. The four dimensions below frame the most actionable implications.
Growth stage with annual volume easing from 2023 peak
The field is classified as Growth: recent three-year filings are well above the prior three-year window, confirming sustained momentum on a multi-year basis. However, annual volume has eased from its 2023 peak, suggesting the initial wave of foundational topology patents may be maturing even as adjacent application areas continue to attract new filers. Late-period data should be interpreted cautiously given publication lag.
Growth stageModerate concentration with two dominant corporate groups
The top five filers hold 37% of the hundred largest filers’ combined output, which is moderate rather than oligopolistic. However, consolidating the two Delta Electronics entities and the two ABB entities reveals that effective corporate concentration is meaningfully higher. Mid-tier entrants such as Georgia Tech Research Corporation, Huawei Digital Power, and LS Electric each hold defensible positions with focused portfolios.
Moderate concentrationLimited co-filing; ABB internal collaboration is the only confirmed instance
The only identified co-filing relationship is between ABB (Schweiz) AG and ABB E-Mobility BV, which have jointly filed 4 patent families. This is an intra-corporate pairing rather than an external partnership. No cross-company or university–industry co-filing relationships are identified in the current evidence, suggesting the ecosystem has not yet developed strong open-innovation habits in this domain.
Low co-filing activityUS-centric filing with meaningful European and PCT coverage
The United States leads all filing jurisdictions, followed by Europe (EPO) and WIPO (PCT). India appears as the fourth jurisdiction, reflecting activity from Indian academic and research institutions visible in the applicant list. China-designated filings are relatively low despite Chinese entities (Delta Electronics Shanghai, Huawei Digital Power) being prominent filers, which may indicate a deliberate strategy of seeking protection in end-markets rather than at home.
US-led, EPO secondaryGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| ABB (Schweiz) AG | ABB E-Mobility BV | 4 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Delta Electronics and Hitachi Energy lead on volume; momentum favors new entrants
The two front-runners differ in their technology emphasis and trajectory: Delta Electronics (CN) concentrates on DC/DC and AC/DC conversion subclasses, while Hitachi Energy extends its coverage into EV propulsion standards. Several challengers entered the recent filing window for the first time, indicating the competitive set is still forming.
Delta Electronics Inc (CN)
Delta Electronics (CN) holds 21 patent families, the largest portfolio in the landscape. Its technology focus is concentrated in H02M subclasses covering DC/DC conversion (H02M3), general power-conversion front-ends (H02M1), and AC/DC rectification (H02M7). Momentum has moderated (▼ –46% in the recent window), suggesting the company is consolidating rather than aggressively expanding its filing rate — though it retains the largest absolute position. Its Shanghai-based affiliate (Delta Electronics Shanghai, 12 patent families, ▲ new entrant in the recent window) adds further effective scale to the corporate group.
patent families: 21Hitachi Energy Ltd
Hitachi Energy holds 17 patent families and is classified as a new entrant in the recent filing window (▲ new entrant), indicating its portfolio was built largely in the current period and is still growing. Its technology mix is notable for including B60L53 (EV charging infrastructure standards) alongside the dominant H02M subclasses, giving it broader application-level coverage than most peers. The Hitachi Energy Switzerland AG entity adds 3 further patent families within the same corporate group.
patent families: 17| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| Delta Electronics Inc | 7 | ▼ -46% |
| Georgia Tech Research Corporation | 6 | ▲ new entrant |
| Hitachi Energy Ltd | 9 | ▲ new entrant |
| Delta Electronics (Shanghai) Co Ltd | 11 | ▲ new entrant |
| Huawei Digital Power Technologies Co Ltd | 6 | ▲ new entrant |
| ABB (Schweiz) AG | 7 | ▲ new entrant |
| Huawei Technologies Co Ltd | 2 | ▲ new entrant |
| LS Electric Co Ltd | 9 | ▲ new entrant |
Under-served branches in magnetics, protection, and measurement
Several IPC branches adjacent to the dominant power-conversion core carry very low patent counts relative to the overall corpus. These represent observations of relative sparsity; where a branch also has plausible technical relevance and a realistic entry path, it merits closer attention.
H01F · Transformer magnetics and high-frequency inductors
With only 10 patent records in this branch — roughly 3% of the activity in the dominant H02M branch — the magnetic design layer of solid-state transformers is significantly under-protected. High-frequency transformer cores, winding geometries, and magnetic materials for wide-bandgap device integration are technically critical to SST efficiency and power density, yet remain sparsely claimed. Researchers or manufacturers with expertise in ferrite or nanocrystalline core design could find defensible space here with relatively few blocking patents. The entry path is through material-level and geometry-level claims rather than system-level topology claims, which are already densely occupied.
Search this in Eureka →H02H · Protective circuit arrangements for SST systems
Only 6 patent records cover protection circuits in this landscape, representing roughly 2% of the activity concentrated in the power-conversion branch. As SSTs for EV charging must handle bidirectional power flow, fault isolation, and grid-disturbance ride-through, protection circuit design is a commercially important but currently sparse area. The low count may reflect that protection is embedded in broader system claims rather than claimed separately — which itself represents a gap a challenger could exploit through dedicated fault-protection architecture patents. Entry could be achieved through claims specific to SST fault-current management and arc-flash protection at the medium-voltage interface.
Search this in Eureka →How top applicants differ across technology routes
Strength of each leader across the main technology routes.
| Player | H02M 3 · Power conversion (AC/DC etc.) | H02M 1 · Power conversion (AC/DC etc.) | H02M 7 · Power conversion (AC/DC etc.) | H02J 7 · Power supply & grid systems | B60L 53 · Electric vehicle propulsion |
|---|---|---|---|---|---|
| Delta Electronics Inc | Strong · 16 | Strong · 14 | Strong · 12 | Moderate · 8 | Emerging · 3 |
| Georgia Tech Research Corporation | Strong · 11 | Strong · 6 | Strong · 8 | Absent | Moderate · 4 |
| Hitachi Energy Ltd | Strong · 8 | Strong · 8 | Absent | Moderate · 4 | Moderate · 4 |
| Delta Electronics (Shanghai) Co Ltd | Strong · 10 | Strong · 10 | Absent | Absent | Absent |
| Huawei Digital Power Technologies Co Ltd | Absent | Strong · 9 | Strong · 7 | Absent | Absent |
| UT Battelle LLC | Absent | Absent | Absent | Strong · 8 | Strong · 8 |
| McMaster University | Strong · 6 | Absent | Absent | Strong · 4 | Strong · 4 |
Frequently asked questions
The current corpus contains 187 patent families in scope. Activity was negligible before 2020 and the field reached its recorded annual peak in 2023, with the three-year recent window running 75% above the prior three-year window.
Delta Electronics (CN) leads with 21 patent families, followed by Hitachi Energy (17), Georgia Tech Research Corporation (13), Delta Electronics (Shanghai) (12), and Huawei Digital Power Technologies (11). The top five filers account for 37% of the combined output of the hundred largest filers.
The United States leads with 71 patent records, followed by Europe (EPO) with 49, WIPO (PCT) with 22, and India with 20. China and Germany each have 8 patent records.
H02M (power conversion — AC/DC, DC/DC, etc.) is by far the dominant IPC branch. H02J (power supply and grid systems) and B60L (electric vehicle propulsion) form a secondary tier. Transformer magnetics (H01F) and protective circuits (H02H) are sparsely covered.
The field is in a Growth lifecycle stage: the recent three-year filing window is 75% above the prior three-year window on a multi-year basis. Annual volume has eased from its 2023 peak, and the most recent years are further understated by publication lag, so a definitive judgment on current annual pace is not yet possible.
The most sparsely covered adjacent branches relative to the dominant H02M core are H01F (transformer magnetics and high-frequency inductors, 10 patent records), H02H (protective circuit arrangements, 6 patent records), and G01R (electric and magnetic measurement, 4 patent records). These areas have plausible technical relevance to SST system performance but contain relatively few blocking patents at present.
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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.
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