How a Special Box Turns Solar Panel Power into Home Electricity
This patent describes a device that takes the unique direct current (DC) electricity from each layer of a special multi-layer solar panel and converts it into alternating current (AC) electricity usable in homes, making sure to get the most power out of each layer.
Original patent title: “Apparatus and method for producing AC power”
This patent describes a device that takes the unique direct current (DC) electricity from each layer of a special multi-layer solar panel and converts it into alternating current (AC) electricity usable in homes, making sure to get the most power out of each layer. Granted to Sunlight Photonics in 2016 with 33 claims and 1 forward citation, and it is expected to expire in 2032.
Coverage
What does this patent actually cover?
This patent describes an electrical power conversion device that takes direct current (DC) energy from a multi-junction solar cell and turns it into alternating current (AC) energy. A multi-junction solar cell has several layers, or "junctions," each producing its own DC electricity. The device has multiple input pairs (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1) to receive DC energy from each of these different junctions. It then uses multiple DC-to-AC inverting circuits (Claim 1), one for each input, to convert that DC energy into AC. An important part is the Maximum Power Point Tracking (MPPT) circuit (Claim 1), which ensures that the device always pulls the most power possible from the solar cell junctions. For example, if a multi-junction solar cell has three layers, this device would have three separate inputs and three separate DC-to-AC inverting circuits, each optimized to convert the power from its specific layer.
The gap
What does this patent NOT cover?
- Does not cover power conversion devices for single-junction solar cells.
- Does not cover systems that combine the DC outputs from different junctions before converting them to AC.
- Does not cover converting DC power from sources other than multi-junction solar cells.
- Does not cover power conversion without an MPPT circuit to maximize energy harvest.
- Does not cover devices where the power conversion components are not housed within a single package (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The noveltynoveltyThe requirement that an invention be different from anything publicly known before its priority date.Read more → lies in individually managing and converting the DC output from each separate junction within a multi-junction solar cell, rather than treating the entire cell as a single DC source. This allows for more precise Maximum Power Point Tracking and conversion for each layer, maximizing overall energy yield.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Concentrated photovoltaic (CPV) systems
Spacecraft solar arrays
High-efficiency solar panels for specialized applications
Microinverters designed for multi-junction cells
Why it matters
The bigger picture
Multi-junction solar cells are known for their high efficiency, especially in concentrated solar power or specialized applications like spacecraft. This patent addresses a challenge with these cells: optimizing power extraction from each individual junction. By converting each junction's output separately, the device can maximize the overall energy harvested, even if different junctions are performing differently due to varying light conditions or degradation. This approach can lead to more efficient solar power systems, particularly in niche high-performance solar markets.
Filed
September 28, 2012
Granted
July 12, 2016
Market context
Who's building on this
Companies in this space
Companies developing high-efficiency solar cells and power electronics for specialized applications, such as those in the concentrated photovoltaic (CPV) sector or aerospace, would be interested in this technology. Sunlight Photonics Inc., the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, focuses on advanced solar energy solutions. Other companies like SolAero Technologies (now part of Rocket Lab) and Spectrolab (now part of Boeing) work with multi-junction cells for space applications.
Market impact
This patent addresses a specific challenge in the high-efficiency solar market, particularly for multi-junction solar cells. By enabling more efficient power extraction from each junction, it could contribute to higher overall system efficiencies for specialized applications where space or weight is critical, such as satellites or high-performance terrestrial CPV systems. It provides a method to maximize the value derived from expensive, high-performance multi-junction cells, potentially reducing the overall cost of energy for these niche uses.
Claim 1 — Plain English
What this patent covers
This patent describes an electrical power conversion device that takes direct current (DC) energy from a multi-junction solar cell and turns it into alternating current (AC) energy. A multi-junction solar cell has several layers, or "junctions," each producing its own DC electricity. The device has multiple input pairs (Claim 1) to receive DC energy from each of these different junctions. It then uses multiple DC-to-AC inverting circuits (Claim 1), one for each input, to convert that DC energy into AC. An important part is the Maximum Power Point Tracking (MPPT) circuit (Claim 1), which ensures that the device always pulls the most power possible from the solar cell junctions. For example, if a multi-junction solar cell has three layers, this device would have three separate inputs and three separate DC-to-AC inverting circuits, each optimized to convert the power from its specific layer.
The clever bit
The novelty lies in individually managing and converting the DC output from each separate junction within a multi-junction solar cell, rather than treating the entire cell as a single DC source. This allows for more precise Maximum Power Point Tracking and conversion for each layer, maximizing overall energy yield.
What it does not cover
- Does not cover power conversion devices for single-junction solar cells.
- Does not cover systems that combine the DC outputs from different junctions before converting them to AC.
- Does not cover converting DC power from sources other than multi-junction solar cells.
- Does not cover power conversion without an MPPT circuit to maximize energy harvest.
- Does not cover devices where the power conversion components are not housed within a single package (Claim 1).
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Early stage
Citation count
6/40
Early citations
Claim breadth
20/20
Very broad protection
Recency
5/20
Granted 10–20 years ago
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$47K – $151K
Midpoint $94K · 6.0 yr remaining · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
33 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Cyrus, M., Frolov, S., & Bruce, A. J. (2016). How a Special Box Turns Solar Panel Power into Home Electricity (U.S. Patent No. 9,391,457). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/9391457/apparatus-and-method-for-producing-ac-power
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US9391457"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4965188 · 1990
How to Make Many Copies of a DNA Piece with Heat
This patent describes the Polymerase Chain Reaction (PCR) method, a technique to make millions of copies of a specific DNA segment using a heat-resistant enzyme and repeated temperature changes.
Cetus Corp
US 4235871 · 1980
How to Encapsulate Active Materials in Lipid Bubbles Efficiently
This patent describes a method for trapping biologically active substances inside tiny, multi-layered fat bubbles called liposomes, using a specific water-in-oil emulsion and gel-forming process to improve how much material gets captured.
Individual
Semantically similar
You might also find these interesting
US 9287431 · 2016 · Alliance for Sustainable Energy
How to Make High-Efficiency Solar Cells with Stacked Layers
US 8912428 · 2014 · Epir Technologies
Solar Cells Made of Stacking Layers with Different Energy Gaps
US 9293619 · 2016 · Solexel
Solar Cells with Built-in Smart Electronics on the Back
US 2780765 · 1957 · Bell Telephone Laboratories Inc
How the First Practical Silicon Solar Cell Works
More to explore
More in Consumer Electronics
US 7657849 · 2010 · Apple Inc
How the iPhone's Slide-to-Unlock Gesture Works
US 7479949 · 2009 · Apple Inc
How Touchscreens Understand Your Finger Swipes and Scrolls
US 4528643 · 1985 · FPDC Inc
How Stores Make Custom Products On-Demand with Remote Approval
US 7469381 · 2008 · Apple Inc
How Touchscreens Show and Snap Back When You Scroll Past an Edge
New to patents?
Common Questions
Frequently Asked Questions
What does How a Special Box Turns Solar Panel Power into Home Electricity cover?
This patent describes a device that takes the unique direct current (DC) electricity from each layer of a special multi-layer solar panel and converts it into alternating current (AC) electricity usable in homes, making sure to get the most power out of each layer.
Who owns patent US 9391457?
Sunlight Photonics owns this patent, granted in 2016.
When does this patent expire?
This patent is expected to expire on September 28, 2032, when the invention enters the public domain.
What is patent US 9391457 cited by?
This patent has been cited by 1 later patents that build on its ideas.
What problem does this patent solve?
Multi-junction solar cells are known for their high efficiency, especially in concentrated solar power or specialized applications like spacecraft. This patent addresses a challenge with these cells: optimizing power extraction from each individual junction. By converting each junction's output separately, the device can maximize the overall energy harvested, even if different junctions are performing differently due to varying light conditions or degradation. This approach can lead to more efficient solar power systems, particularly in niche high-performance solar markets.
What does this patent NOT cover?
Does not cover power conversion devices for single-junction solar cells.
Patent monitoring