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Solar energy. Dual-axis trackers. Patent Analysis

Aenert news. Invention analysis
Earlier, we have revised several subjects related to Concentrated solar power technologies, including solar energy storage technologies (05.06.2022 and 09.01.2023), solar tracking systems in general (20.06.2022) and single-axis tracking systems (22.12.2022). In this article we will analyze patents published in the past 20 years and recent patent applications in the field of dual-axis solar trackers. The documents under revision have been published in 37 patent offices around the world by 1542 applicants from 33 countries.

The peak values in the number patent applications were achieved in 2010-2014. The largest numbers of published patents were registered in 2012-2013 and 2016-2017. In recent years, the number of patent applications has declined, while the number of patents was on a moderate level. The share of start documents that didn’t belong to any previously formed patent family in recent years was about 60% on average.

Solar energy. Dual-axis trackers. Cumulative number of patents and applications*, relationship of number of applications to total number of documents by year


*Areas representing patents and applications are overlapping

In recent years, a growth in the number of new IPC subgroups is seen in the collection of patents and patent applications in this field. This can mean that the subject is expanding towards new technological areas, although, it should be borne in mind that this section of IPC classification has undergone substantial changes in the second half of the past decade. The number of new patent offices was above average several years ago, but recently has declined. The number of new applicants was at a moderate level during the last years. All this can indicate that the peak of the inventive activity in this field has passed, but the interest is still holding at a substantial level.

In the revised pool of documents, the largest number of patents were issued during 20 years in the CNIPA (CN) patent office – more than 31% of all patents. USPTO (US) and KIPO (KR) followed the leader with almost 22% and more than 16%, respectively. JPO (JP), OEPM (ES), IP Australia (AU), and EPO should also be mentioned for having a considerable number of patents granted. In the collection of patent applications, CNIPA (CN) was also in the lead with more than 46%. It was followed by USPTO (US) and WIPO, each having about 13% of applications.

Solar energy. Dual-axis trackers. Breakdown of inventions by patent offices. Patents, 20 years (left); Applications, 5 years (right)



Residents of China were leading in both the case of patents granted during the 20-year period (around 27% of cases) and in the case of recent patent applications (around 44% of cases). In the collection of patents, China was followed by residents of the United States, South Korea, and Spain. While in patent applications – by residents of the United States, Japan, and Spain.

Below is a list of top 10 applicants having the highest Market involvement ratio for patents published in the 20-year period (Market involvement ratio = volume ratio multiplied by ownership ratio, where Volume ratio - share of applicant documents in total number of documents, Ownership ratio - applicant's participation share in total number of documents):

Solar energy. Dual-axis trackers. Top applicants by Market involvement ratio. Patents

StatusCountryNameVolume
ratio, %
Ownership
ratio, %
Market involvement
ratio, %
CompanyUSSunPower Corporation2.3594.72.23
CompanyESAbengoa Solar New Technologies, S.A.1.7195.311.63
CompanyJPMitsui Engineering & Shipbuilding Co., Ltd1.691.131.46
OrganizationCNBIGC Beijing Institute of Graphic Communication1.491001.49
CompanyUSSolarCity Corporation1.391001.39
CompanyESSENER Ingenieria y Sistemas S.A.1.171001.17
OrganizationDEFraunhofer-Gesellschaft zur Förderung der Angewandten Forschung e.V.0.9650.370.48
CompanyDESoitec Solar, GmbH0.9672.330.69
CompanyUSeSolar, Inc.0.851000.85
OrganizationCNTYUST Taiyuan University of Science & Technology0.851000.85

 
Among the patents related to dual-axis solar trackers, the leading applicants by the number of documents were SunPower Corporation (US) – 22 patents, Abengoa Solar New Technologies, S.A. (ES) – 16, and Mitsui Engineering & Shipbuilding Co., Ltd (JP) – 15. In the collection of recent patent applications, the leaders were Sumitomo Electric Industries, Ltd. (JP) - 26, NEXTracker Inc. (US) - 17, and SFS Acquisition, LLC (US) - 15 patent applications.

Solar energy. Dual-axis trackers. Top applicants by Market involvement ratio. Applications

 

StatusCountryNameVolume
ratio, %
Ownership
ratio, %
Market involvement
ratio, %
CompanyJPSumitomo Electric Industries, Ltd.4.651004.65
CompanyUSNEXTracker Inc.3.041003.04
CompanyUSSFS Acquisition, LLC2.6896.672.59
CompanyESSENER Ingenieria y Sistemas S.A.1.971001.97
CompanyUSAlion Energy Inc1.971001.97
CompanyATSmart Flower Energy Technology GmbH1.79951.70
CompanyFROptimum Tracker1.251001.25
CompanyCHElemental Eng Ag1.251001.25
PersonESCarrascosa Perez Marco Antonio1.071001.07
CompanyJPSOLARFLAME CORPORATION1.071001.07


In the pool of patents and patent applications related to dual-axis trackers, the most encountered problems were Low efficiency due to solar movement, High costs of equipment production, and High costs of repair and replacement. In the vast majority of cases, technical solutions disclosed in the patent documents under revision were represented in the form of devices. Methods were encountered less often in the documents, while the number of compositions was negligible. The most popular IPC subgroups assigned to the patent documents were: H02S20/32 (specially adapted for solar tracking), F24J2/38 (employing tracking means), F24J2/54 (specially adapted for rotary movement), G05D3/12 (using feedback), and H01L31/042 (PV modules or arrays of single PV cells).

In the collection of documents under consideration, the largest patent families comprise 31 and 21 patent documents and are represented by core documents US20180294769A1 and WO2015126890A1, respectively (Core document is a base document for which a complete description of the invention is available in generally-accessible patent databases). They are followed by three patent families each having 19 documents that are represented by core documents US20150007870A1, US20200153381A1, and US20110240007A1:

Pivot and Fanning Drive for Solar Panels / A: US20180294769A1 / IPC: H02S30/20, H02S20/30, F16M13/02, F24S20/50, F24S30/48 / Stoger Elmar, Swatek Alexander, Zach Gerald / SMART FLOWER ENERGY TECHNOLOGY GMBH / Appl. date: 20/09/2016; Publ. date: 11/10/2018 / United States Patent and Trademark Office / Core document: US20180294769A1 / Technology categories: G / Technology elements: OAE, TR, Tda, Tfp, Tms, Tsp / Problems: HCEP, HCRR / Technical solution types: D / Claims: 15 / Rating: 10

TORSION LIMITER DEVICES, SYSTEMS AND METHODS AND SOLAR TRACKERS INCORPORATING TORSION LIMITERS / A: WO2015126890A1 / IPC: F24J2/38 / CORIO Ronald P / CORIO Ronald P / Appl. date: 18/02/2015; Publ. date: 27/08/2015 / World Intellectual Property Organization / Core document: WO2015126890A1 / Technology categories: G / Technology elements: TR, Tda, Tfp, Tms, Tsa, Tsp / Problems: HCEP, LEEF / Technical solution types: D, M / Claims: 19 / Rating: 9

Heliostat Repositioning System and Method / A: US20150007870A1 / IPC: F24J2/38, H01L31/052, H01L31/042 / Currier Thomas Joseph / Qbotix Inc / Appl. date: 25/09/2014; Publ. date: 08/01/2015 / United States Patent and Trademark Office / Core document: US20110240007A1 / Technology categories: CPV, ST / Technology elements: TR, Tcc, Tda, Tfp, Tms / Problems: HCM, HCPC, LESM / Technical solution types: D / Claims: 20 / Rating: 11

SOLAR ARRAY WITH REFERENCE SOLAR POWER PLANT FOR IMPROVED MANAGEMENT / A: US20200153381A1 / IPC: H02S20/32, G05D3/10, F24S30/425 / MICHOTTE DE WELLE Madyan, ARLIAUD Jerome / NEXTracker Inc. / Appl. date: 27/12/2016; Publ. date: 14/05/2020 / United States Patent and Trademark Office / Core document: US20200153381A1 / Technology categories: G / Technology elements: CS, TR, Tda, Tfp, Tss / Problems: HCG, LEEF, LESM / Technical solution types: D, M / Claims: 11 / Rating: 11

HELIOSTAT REPOSITIONING SYSTEM AND METHOD / A: US20110240007A1 / IPC: F24J2/38, F24J2/40, F24J2/52 / Currier Thomas / BLACK SWAN SOLAR, INC. / Appl. date: 27/05/2011; Publ. date: 06/10/2011 / United States Patent and Trademark Office / Core document: US20110240007A1 / Technology categories: CPV, ST / Technology elements: TR, Tcc, Tda, Tfp, Tms / Problems: HCM, HCPC, LESM / Technical solution types: D / Claims: 20 / Rating: 11


The following abbreviations are used in the documents hereinbefore and hereinafter: D - Device; M - Method; CPV - Concentrator photovoltaics; G - CSP or PV in general; ST - Solar tower; OAE - Other auxiliary equipment; CS - Control systems; TR - Trackers; Tss - Tracking systems; Tsr - Sensors; Tms - Tracking mechanisms; Tsp - Tracker support structures; Tfp - Flat-panel trackers; Tcc - Concentrating collector trackers; Tsa - Single-axis trackers; Tda - Dual-axis trackers; HCEP - High costs of equipment production; HCG - High costs in general; HCM - High costs of maintenance; HCPC - High costs of plant construction; HCRR - High costs of repair and replacement; LEEF - Low efficiency due to environmental factors; LESM - Low efficiency due to solar movement.

Solar energy. Dual-axis trackers.  Breakdown of documents by family size. Patents and applications



Some examples of inventions related to dual-axis solar trackers and having the highest rating calculated using Advanced Energy Technologies methodology are provided below:

Solar energy. Dual-axis trackers. Prominent patent documents by rating:

Entrainement de suiveur solaire (en: Solar tracker drive) / P: MA34337B1 / IPC: F24J2/38, F24J2/54, F24J2/40 / Almy Charles, Barton Nicholas / Sunpower Corporation / Appl. date: 25/12/2012; Publ. date: 01/06/2013 / Moroccan Industrial and Commercial Property Office / Core document: MA34337B1 / Technology categories: CPV / Technology elements: TR, Tcc, Tda, Tfp, Tms, Tsa, Tss / Problems: HCEP, LESM / Technical solution types: D, M / Claims: 20 / Rating: 21

Suitable Control Method for A System of Photovoltaic Concentration Modules / P: MA35855B1 / IPC: F24J2/38, G01S3/786, G05F1/67 / Ortega Linares Manuel Gil, Rodriguez Rubio Francisco, Guerrero Cano Manuel, Noriega Gil Pablo / ABENGOA SOLAR NEW TECHNOLOGIES S.A. / Appl. date: 11/07/2014; Publ. date: 01/12/2014 / Moroccan Industrial and Commercial Property Office / Core document: US20150013751A1 / Technology categories: CPV / Technology elements: CS, TR, Tcc, Tda, Tsr, Tss / Problems: LEEF, LESM / Technical solution types: D, M / Claims: 16 / Rating: 20

Drive with integrated inclination sensor / P: US10520224B2 / IPC: F24S50/20, F24S30/00, F24S30/425, F24S50/80, H02S20/32 / Linderman Ryan, Barton Nicholas / Sunpower Corp / Appl. date: 31/01/2018; Publ. date: 31/12/2019 / United States Patent and Trademark Office / Core document: US9353970B2 / Technology categories: CPV, G / Technology elements: TR, Tcc, Tda, Tfp, Tss / Problems: HCEP, HCPC / Technical solution types: D / Claims: 19 / Rating: 19

Drive with integrated inclination sensor / P: US9920957B2 / IPC: H02S20/32 / Linderman Ryan, Barton Nicholas / SUNPOWER CORPORATION / Appl. date: 27/05/2016; Publ. date: 20/03/2018 / United States Patent and Trademark Office / Core document: US9353970B2 / Technology categories: CPV, G / Technology elements: TR, Tcc, Tda, Tfp, Tss / Problems: HCEP, HCPC / Technical solution types: D / Claims: 20 / Rating: 19

Sun tracking solar power system hardware and method of assembly / P: US9998064B2 / IPC: H02S20/10, H02S20/32, H01L31/052, H01L31/042 / Wares Brian S, Grushkowitz Tyler, McKibben Nicholas / SunPower Corporation / Appl. date: 07/10/2015; Publ. date: 12/06/2018 / United States Patent and Trademark Office / Core document: US20150187975A1 / Technology categories: G / Technology elements: TR, Tcc, Tda, Tfp, Tsa, Tsp / Problems: HCEP, HCM, HCPC / Technical solution types: D / Claims: 20 / Rating: 19

SUN TRACKING SOLAR POWER SYSTEM HARDWARE AND METHOD OF ASSEMBLY / P: US9184324B2 / IPC: H01L31/042, H01L31/052, F24J2/54, F24J2/38 / Wares Brian S, Grushkowitz Tyler, McKibben Nicholas / SUNPOWER CORPORATION / Appl. date: 30/12/2013; Publ. date: 10/11/2015 / United States Patent and Trademark Office / Core document: US20150187975A1 / Technology categories: G / Technology elements: TR, Tcc, Tda, Tfp, Tsa, Tsp / Problems: HCEP, HCM, HCPC / Technical solution types: D / Claims: 19 / Rating: 19

SUITABLE CONTROL METHOD FOR A SYSTEM OF PHOTOVOLTAIC CONCENTRATION MODULES / P: MX344410B / IPC: F24J2/10, F24J2/38, F24J2/40, G01S3/786, G05F1/67, H01L31/02, H02S50/00 / ORTEGA LINARES Manuel Gil, RODRÍGUEZ RUBIO Francisco, GUERRERO CANO Manuel, NORIEGA GIL Pablo / ABENGOA SOLAR NEW TECHNOLOGIES S.A / Appl. date: 14/12/2012; Publ. date: 13/12/2016 / Mexican Institute of Industrial Property / Core document: US20150013751A1 / Technology categories: CPV / Technology elements: CS, TR, Tcc, Tda, Tsr, Tss / Problems: LEEF, LESM / Technical solution types: D, M / Claims: 16 / Rating: 19


In the collection of documents related to dual-axis tracking systems, three major groups with the largest number of documents can be highlighted. They include patents and patent applications that concern Solar Tower technologies, and that to some extent solve problems of High costs of equipment production and High costs of repair and replacement. Below we provide several examples of inventions from these three groups of documents.

- US11169241B2 - improved tracking accuracy and lower costs are achieved by a tracking sensor comprising a photosensitive detection component with at least five photosensitive elements, at least one of which is for sensing radiation intensity;

- US10890645B2 - a solar tracking method based on GPS data related to the time, date, and location of the device, comprising repeatedly calculating angular and linear motion paths and error corrections. The method is applicable to solar power towers and is aimed at lowering equipment costs;

- US11387773B2 - structural stability of heliostat is improved by a design comprising a solar battery panel frame held by a truss structure with three connection points and rotatable in two directions by extension and contraction of actuators and comprising central crossbars, coupling members, and other elements;

- WO2017097712A1 - a dual-axis heliostat design comprising an anti-astigmatism system is aimed to reduce costs, improve heliostat performance, and resistance to bending loads;

- US11082001B2 - a dual-axis heliostat includes a frame comprising a horizontal top rail and several leg members with footing and mounting surface, an optical assembly comprising concrete and hanging from the frame. The optical assembly is moved by actuators, based on the data from a camera. The invention provides a cost-effective and wind resistant design.



High costs of equipment production

A solar tracker sensor is disclosed in patent US11169241B2 published by Suzhou Jsolar Incorporated (CN).  The sensor comprises an optical component made of a black weather resistant material comprising a cover plate, positioning and light transmission holes (openings of different sizes), a control component, an interface component, a circuit board with several detection components (photosensitive and tilt angle detection components). The photosensitive detection component is facing a radiation source, while the tilt angle detection component is faced away from it. The photosensitive detection component comprises at least five photosensitive elements, at least one of which is for sensing radiation intensity. The sensor further comprises a tempered glass protective housing with an outlet (four core shielded cable), a waterproof vent, and a circuit board placement interface. The claims of the invention further specify method of operating the sensor.

With reference to prior art solutions, the authors mention high cost of tracking sensors and low accuracy.

The invention belongs to a family consisting of 7 patent documents published in CN, WO, and US in 2017-2021.



Image from: US11169241B2

401 - protective housing; 402-1,402-2 - optical components; 403-1,403-2,403-3,403-4 - optical channels; 404-1,404-2,404-3,404-4 - bumps; 405-1,405-2 - plug connectors; 406 - outlet; 407 - waterproof vent; 409-1,409-2 - bodies; 410-1,410-2 - cover plates.


Patent US10890645B2 by Wts Llc (US) discloses a method of tracking the sun for dual-axis solar applications, such as solar panels, solar concentrators, or heliostats. The method comprises receiving GPS data related to the time, date, and location of the device, determining an azimuth and altitude of the sun, calculating a first angular motion path to accommodate the second angular motion path, the motion paths corresponding to the two axes of rotation. The angular motion paths are used to calculate a first and a second linear motion paths, which, in turn are used to direct the solar device by the means of linear motors. This procedure is repeated at timed intervals during the day. The method further comprises calculating an error correction for the motion paths "…by referencing an error correction lookup table and using bicubic interpolation to interpolate an error correction".

The authors of the invention point out that this kind of tracker can be applied in solar power tower applications. Among the drawbacks of the prior-art solutions, the authors mention high cost of equipment involved.

The invention belongs to a patent family comprising 9 documents published between 2016 and 2021 in the US, WO, EP, and CN patent offices.



Image from: US10890645B2

100 - tracking device; 110 - payload



High costs of repair and replacement

Patent US11387773B2 published on 12.07.2022 by Solarflame Corporation (JP) discloses a heliostat apparatus capable of moving in two directions. The heliostat comprises a solar battery panel frame held by a truss structure, a north-south and an east-west rotation mechanisms, a frame support. In one embodiment of the invention, the north-south rotation mechanism comprises "…a central crossbar that penetrates the support and that can be oscillated in the east-west direction", a coupling member and an actuator between the crossbar and the frame. The frame is rotated by extension and contraction of the actuator. The truss structure is formed from three points - a coupling portion of the coupling member and the frame, a coupling portion of the central crossbar and the actuator, and a coupling portion of the actuator and the frame. The claims of the invention specify other structural element of the heliostat, as well as alternative variants of their mutual arrangement.

The invention is aimed at providing improved stability of the heliostat to reduce its vulnerability to wind and other loads. The patent belongs to a patent family comprising 8 documents published in JP, WO, TW, CN, EP, and US in 2019-2022.



Image from: US11387773B2

1 - heliostat apparatus; 2 - solar battery panel; 2A - panel surface; 3 - frame; 4 - elevation angle rotation axis; 5 - north-south rotation mechanism; 6 - azimuth angle rotation axis; 7 - east-west rotation mechanism; 8 - support; 9 - north-south frame member; 10 - east-west frame member; 13 - east-west rotating member; 14 - coupling member for east-west rotation; 15 - actuator for east-west rotation; 21 - central crossbar; 22 - coupling member for north-south rotation; 23 - actuator for north-south rotation.


Patent application WO2017097712A1 filed by Carrascosa Perez Marco Antonio (ES) describes a dual-axis tracking heliostat. The heliostat comprises a pedestal, a torque tube, a number of arms attached to the tube, a number of facets attached to the arms. An azimuth drive and a horizontal support are positioned on top of the pedestal and connected with the tube through zenith pivots and zenith lugs with hinge pins (ball and socket joints). A zenith drive is pivotably connected to the horizontal support and to the tube. The heliostat further comprises an "…anti-astigmatism system made up of a lattice configuration connecting consecutive arms (9) of the heliostat and the torque tube". The claims of the invention further provide detailed description of a structural reinforcement of the torque tube, pivoting connections, and other structural elements of the heliostat, as well as their mutual arrangement.

The authors state that such design can be used in central solar tower technology and provides improved aiming precision, improved heliostat performance, improved resistance to bending loads due to gravity or wind, reduced costs, etc.

The application is a part of a family consisting of 8 patent documents published in EP, WO, CN, and MA in 2017-2020.



Image from: WO2017097712A1

1 - pedestal; 1' - control cabinet; 2 - torque tube; 3 - azimuth drive; 4 - horizontal support or table; 5 - zenith pivots; 7 - zenith drive; 8 - zenith lugs; 9 - arms; 10 - facet anchoring points; 11 - facets; 12 - shared anchors of the arms; 16 - Structural elements of the anti-astigmatism system.



Solar tower

A self-ballasted dual-axis heliostat is described in patent US11082001B2 by Heliogen, Inc. (US). The heliostat includes a frame comprising a horizontal top rail and several leg members, comprising a footing, and a mounting surface, on which the heliostat rests. Optical assembly comprising concrete hangs from the frame between the leg members on several wires connected to its center. Actuators mounted at the underside of the optical assembly move it in two perpendicular directions by reeling the wires in and out via wire guides. The optical assembly further comprises a tracking controller to energize the actuators.  The heliostat includes a tracking controller that determines and alters the orientation of the optical assembly based on the images made by a camera. The heliostat further comprises a cleaning assembly with a wiper blade to remove debris, a reservoir for capturing water, and a pump for spraying it on the optical assembly.

The authors mention that such heliostat can be used in central tower concentrated solar power plants. The aim of the invention is to provide a cost-effective and wind resistant heliostat design.

The patent is a part of a family comprising 8 patent documents published between 2019 and 2023 in the US, WO, AU, CN, CL, and ZA patent offices.



Image from: US11082001B2

100 - heliostat; 101 - frame; 102A,102B,102C - leg members; 104 - top rails; 106 - footpad; 120 - optical assembly; 122 - mirror; 130A,130B,130C - suspension wires; 132 - vertex; 140 - wire guide; 150 - tracking controller.


Analysis of these and other inventions shows that the inventors almost equally focus on both Concentrating collector trackers and Flat-panel trackers. In the majority of cases, the inventions describe novel Tracker support structures (such as frames, bearings, supports, pedestals, etc.) and Tracking mechanisms (such as motors, actuators, drive systems, rotation devices, etc.).

More detailed information about inventions in the field of solar trackers, and patent research methodology can be found on aenert.com and in SOLAR ENERGY. Solar Trackers. Extended patent report. June 2022.


By the Editorial Board