Aenert news. Invention analysis
In our earlier articles we discussed patenting trends in several general fields of solar energy production technology, including concentrating photovoltaics (30.04.2023), solar energy storage systems (05.06.2022 and 09.01.2023), and experimental and unconventional solutions (08.04.2023). Further, we also revised a set of aspects of solar tracking systems for concentrating and non-concentrating solar power (solar trackers: 20.06.2022, single-axis trackers: 22.12.2022, dual-axis trackers: 27.03.2023, and tracking sensors: 20.05.2023). Today, we will continue this series with an article covering the subject of tracking mechanisms, such as drives, actuators, motors, turning and pivoting arrangements, levers, torque transmission and limiting devices, etc. For this purpose, we have collected more than 3200 inventions published over the past 20 years and analyzed them using the Advanced Energy Technologies methodology. The patents and patent applications under revision were published in 41 patent offices around the world by 1586 applicants from 35 countries.

Solar energy. Tracking mechanisms. 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

The largest numbers of registered patent applications in this field were achieved in 2010-2013 and in 2019, which resulted in substantially high values of granted patents in 2012-2021 with a slight decline towards the recent years. The number of start patent applications, that didn’t belong to previously formed patent families, was varying within the range of 62%-67% in 2017-2020, with a fall to 23% in 2021.

A peak in the number of new applicants appearing in the collection of documents related to the subject under consideration was seen in 2011, after which there was a moderate decline in the values. The number of new IPC subgroups in the documents in general was on a rise, with the largest value achieved in 2018, although it should be borne in mind that IPC classification has recently undergone substantial changes in the solar energy segment. The number of new patent offices was varying throughout the period under consideration, with the peaks in 2010, 2014, and 2019. This may indicate a continuing interest of various applicants in this field of technology, with the attempts to integrate solutions from other technical fields and expand the protection to new regions.

During the twenty-year period, the largest number of patents were granted in CNIPA (CN) – almost 35% of the entire collection of patents. It was followed by KIPO (KR) and USPTO (US), each almost reaching 20%. In the collection of patent applications registered in the past 5 years, CNIPA (CN) was leading with a share exceeding 44%. EPO, JPO (JP), IP Australia (AU), and OEPM (ES) should also be mentioned as the patent offices that granted more than 30 patents each on the subject of interest during the 20-year period.

Solar energy. Tracking mechanisms. Breakdown of inventions by patent offices. Patents, 20 years (left); Applications, 5 years (right)



Residents of China were in the lead by the number of patents granted during the 20-year period with a share of more than 33% of all cases. In the pool of patents, high activity was also shown by residents of South Korea, the United States, Spain, Taiwan, and Germany. In the case of recent patent applications, the first place as well was taken by the residents of China, this time with a share exceeding 43%, they were followed by the residents of the United States and South Korea.

Below we provide a list of top 10 applicants with 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. Tracking mechanisms. Top applicants by Market involvement ratio. Patents

In the collection of patents related to solar power tracking mechanisms, the largest number of documents was issued to SunPower Corporation (US), the company was granted 31 patents. It was followed by six applicants, each of which was granted more than 10 patents: NEXTracker Inc. (US), BIGC Beijing Institute of Graphic Communication (CN), Abengoa Solar New Technologies, S.A. (ES), Big Sun Energy Technology Incorporation (TW), SENER Ingenieria y Sistemas S.A. (ES), and Soltec Energias Renovables, SL (ES). In the collection of recent patent applications, the most active applicants were NEXTracker Inc. (US) - 42 applications, Sunfolding Incorporated (US) - 35, SFS Acquisition, LLC (US) - 15, Arctech Solar Holding Co Ltd (CN) - 13, and SunPower Corporation (US) - 12 applications.

Solar energy. Tracking mechanisms. Top applicants by Market involvement ratio. Applications

Among the patents and patent applications describing technologies and equipment for solar movement tracking mechanisms, the most commonly mentioned problems are Low efficiency due to solar movement, High costs of equipment production, and High costs of repair and replacement. Device is the type of technical solutions the inventors mainly chose for their inventions. Methods are encountered substantially less often in the documents, while the number of compositions is negligible. The most popular IPC subgroups assigned to the patent documents are: H02S20/32 (specially adapted for solar tracking), F24J2/54 (specially adapted for rotary movement), F24J2/38 (employing tracking means), H01L31/042 (PV modules or arrays of single PV cells), and G05D3/12 (using feedback).

The largest patent family of the entire collection made for the present analysis includes 31 patent documents and is represented by core document US20180294769A1 (Core document is a base document for which a complete description of the invention is available in generally-accessible patent databases):

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

It is followed by one patent family having 28 and two families each having 21 patent documents, represented by core documents US20180302025A1, WO2015126890A1 and AU2013200320A1, respectively:

Pneumatic actuator system and method / A: US20180302025A1 / IPC: F15B15/10, H02S20/32 / Basel Louis Hong, Betts Kyle Douglass, et al. / Sunfolding Inc / Appl. date: 17/04/2018; Publ. date: 18/10/2018 / United States Patent and Trademark Office / Core document: US20180302025A1 / Technology categories: G / Technology elements: TR, Tfp, Tms / Problems: UP / Technical solution types: D / Claims: 19 / Rating: 9

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

AUTOMATIC SOLAR TRACKING ADJUSTMENT/CONTROL APPARATUS OF SOLAR GENERATION SYSTEM / A: AU2013200320A1 / IPC: F24J2/38, F24J2/54 / Luo Chia Ching / BIG SUN ENERGY TECHNOLOGY INCORPORATION, LUO CHIA CHING / Appl. date: 22/01/2013; Publ. date: 07/11/2013 / IP Australia / Core document: AU2013200320A1 / Technology categories: G / Technology elements: TR, Tms, Tsa, Tsp, Tss / Problems: LESM / Technical solution types: D / Claims: 21 / Rating: 11

The following abbreviations are used in the documents hereinbefore and hereinafter: D - Device; M - Method; CPV - Concentrator photovoltaics; ST - Solar tower; G - CSP or PV in general; HCEP - High costs of equipment production; 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; UP - Unclear problem; OAE - Other auxiliary equipment; Tcc - Concentrating collector trackers; Tda - Dual-axis trackers; Tfp - Flat-panel trackers; Tms - Tracking mechanisms; TR - Trackers; Tsa - Single-axis trackers; Tsp - Tracker support structures; Tss - Tracking systems.

Solar energy. Tracking mechanisms. Breakdown of documents by family size. Patents and applications



Following are several examples of patent documents having the highest rating calculated using the Advanced Energy Technologies methodology, from the pool of documents related to tracking mechanisms in solar power systems and their production:

Solar energy. Tracking mechanisms. 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

Tracking solar collector assembly / P: US7888588B2 / IPC: E04B7/02, H02N6/00, H01L25/00 / Shingleton Jefferson G / SunPower Corporation, Systems / Appl. date: 27/05/2009; Publ. date: 15/02/2011 / United States Patent and Trademark Office / Core document: US7888588B2 / Technology categories: G / Technology elements: TR, Tfp, Tms, Tsa, Tsp / Problems: HCRR, LESM / Technical solution types: D / Claims: 20 / Rating: 20

Photovoltaic systems with local maximum power point tracking prevention and methods for operating same / P: US9923374B2 / IPC: H02J3/38, H02S50/00 / Judkins Zachary S, Johnston Keith / Sunpower Corp / Appl. date: 14/06/2016; Publ. date: 20/03/2018 / United States Patent and Trademark Office / Core document: WO2013147942A1 / Technology categories: G / Technology elements: OAE, TR, Tfp, Tms / Problems: LESM / Technical solution types: M / Claims: 19 / Rating: 19

Photovoltaic systems with local maximum power point tracking prevention and methods for operating same / P: AU2016225833B2 / IPC: H01L31/042 / Judkins Zachary S, Johnston Keith / Sunpower Corp / Appl. date: 07/09/2016; Publ. date: 05/04/2018 / IP Australia / Core document: WO2013147942A1 / Technology categories: G / Technology elements: OAE, TR, Tfp, Tms / Problems: LESM / Technical solution types: M / Claims: 20 / Rating: 19

Tracking solar collector assembly / P: US7554030B2 / IPC: E04B7/02, H01L25/00, H02N6/00 / Shingleton Jefferson G / SunPower Corporation, Systems / Appl. date: 16/03/2004; Publ. date: 30/06/2009 / United States Patent and Trademark Office / Core document: US7888588B2 / Technology categories: G / Technology elements: TR, Tfp, Tms, Tsa, Tsp / Problems: HCRR, LESM / Technical solution types: D / Claims: 32 / Rating: 19

Actuated feedforward controlled solar tracking system / P: MA33054B1 / IPC: F24J2/38, F24J2/52, F24J2/40 / Oosting Kenneth / Inspired Surgical Technologies Inc. / Appl. date: 22/08/2011; Publ. date: 01/02/2012 / Moroccan Industrial and Commercial Property Office / Core document: WO2010085592A3 / Technology categories: G / Technology elements: TR, Tcc, Tda, Tfp, Tms, Tsa, Tsp, Tss / Problems: HCEP, HCRR, LESM / Technical solution types: D / Claims: 21 / Rating: 18

HELIOSTAT REPOSITIONING SYSTEM AND METHOD / P: AU2015200879B2 / IPC: F24J2/38 / Currier Thomas / SolarCity Corporation / Appl. date: 20/02/2015; Publ. date: 17/11/2016 / IP Australia / Core document: US20110240007A1 / Technology categories: CPV, ST / Technology elements: TR, Tcc, Tda, Tfp, Tms / Problems: HCM, HCPC, LESM / Technical solution types: D / Claims: 41 / Rating: 18

In the pool of recent patents and patent applications related to solar tracking mechanisms, the most noticeable groups of inventions were those aimed at solving the problems of Low efficiency due to solar movement, High costs of equipment production, and High costs of repair and replacement. Below we provide several examples of patent documents that concern these groups of technical solutions:

- US9954481B2 - tracking accuracy is improved by a linear drive apparatus comprising an outer tube having a drive nut, a screw connected to a drive mechanism, and an extension rod with a wear resistant rust-proof layer positioned between the outer tube and the screw, and connected to the drive nut on one end and passing through the sealing end cap of the outer tube with the other end;

- US11101768B2 - solar panel tracking efficiency is improved by a tracking device comprising a torque tube with an energy source on an upper side and an electronic module comprising a DC to DC converter, a battery, a boost converter, a capacitor device, and a micro-controller – on a lower side;

- US11165385B2 - a solar tracking system has a number of posts with actuators on some of them, a torque structure coupling the actuators, damper devices comprising a housing, a friction plate and two flanges on the remaining posts, and seal members between the housing and the torque structure to retain a silicone gel or oil and capable of rotating with the torque structure. The invention is aimed at reducing solar tracker equipment cost;

- US11689151B2 - a table for tracking solar modules comprises a gear element pivotable by a drive shaft having an actuation element capable of engaging into the toothing of the gear element with special pins, to drive or block it. The invention is aimed at providing a less costly solution to compensate various oscillations;

- US11387773B2 - tracking dual-axis heliostat stability is improved by system comprising a frame, a support and two rotational mechanisms. The elevation rotation mechanism includes a crossbar, a coupling member, an actuator to rotate the frame, and a truss structure. The azimuth rotation mechanism comprises a rotating member, a coupling member, an actuator to rotate the frame, and a truss structure.

Low efficiency due to solar movement

Patent US9954481B2 published by China Hainan Sun Source Solar Energy Development Ltd. (CN) describes a linear drive apparatus for solar tracking system. The apparatus comprises an outer tube with a back section on the first end a front section on the second end. The first end is equipped with a sealing cap. A screw is positioned on the outer tube, connected to a drive mechanism, and a drive nut is positioned on the screw. The screw has a length-diameter ratio of 20-25, while for the drive nut this value is 3-5. An extension rod with a wear resistant rust-proof layer is provided between the outer tube and the screw, connected to the drive nut on one end and passing through the sealing end cap with the other end. Sealing is ensured between the extension rod and the end cap, and an insulated ventilation stopper is provided on the outer tube. DC motor serves as the drive mechanism and is equipped with a "…planet reduction gear and Hall signal feedback", and connected to the first end of the screw. The claims of the invention further provide additional details and arrangement options of the system components.

The object of the invention is to provide a drive apparatus for improved tracking accuracy.

The patent is a part of a family comprising 10 documents published in 2013-2018 in CN, WO, AU, EP, and US.



Image from: US9954481B2

16 - connection rod; 17 - solar-energy panel; 18 - mounting base

Patent US11101768B2 by NEXTracker Inc. (US) discloses a solar tracking device comprising a horizontally-oriented cylindrical torque tube with a drive device and solar modules attached thereto. The torque tube is connected by a crank such that it is offset from the drive device. A solar panel energy source up to 300 Watts is disposed side by side with a solar module on top of the torque tube, while a box with an electronic module comprising a DC to DC converter, a battery, a boost converter, a capacitor device for voltage stabilization, and a micro-controller is mounted on a lower side of the tube, separated from the energy source. The drive device is powered by the solar panel energy source and operates with less than 15 Watt-hours per day. The micro-controller is coupled to an inclinometer configured to measure tilt of the panels.

The authors of the invention mention that in previous solutions solar panels don’t convert energy at full potential due to non-optimum position of the panels with respect to the sun.

The patent belongs to a family comprising 7 patent documents, all published in the USPTO (US) patent office between 2016 and 2023.



Image from: US11101768B2

1500 - drive assembly; 5400 - energy system; 5410 - solar panel energy source; 5420 - box; 5430 - electronic module; 5440 - battery

High costs of equipment production

Patent US11165385B2 by Kinematics Llc (US) proposes a solar tracking system having a number of spaced apart posts with actuators (slew drives or electric motors) located on some of them, a torque structure that couples the actuators together and bears solar panels, and damper devices on the posts that don’t have actuators. Each damper device comprises a friction plate coupled to the torque structure and partially enclosed by a housing having top and bottom plates fastened together and encircling a portion of the torque structure, and two flanges extending from the top and bottom plates, respectively. Seal members are placed between the housing and the torque structure capable of retaining a silicone gel or oil within the housing and engaging and rotating with the torque structure and the friction plate. A controller is used to control actuators for proper distribution of a torque to rotate the solar panels by delivering power from such sources as a plugged connection, a battery, or a photovoltaic panel.

The authors state that "…It is desirable to reduce the cost of the energy generated by solar panels" and mention that equipment employed is one of the main costs in solar power production.

Patent family of the invention consists of 5 documents published in WO and US between 2018 and 2021.



Image from: US11165385B2

12 - posts; 14 - torque structure; 17 - longitudinal axis of rotation; 18 - panel portions; 19 - tube structure portions; 20 - panels; 22 - brackets; 30 - multiple actuators

Patent US11689151B2 granted to Ideematec Deutschland GmbH (DE) on 27.06.2023 describes a pivotable module table for solar panel tracking system. The table is coupled to a gear element pivotable by an electrically driven drive shaft having an actuation element and extending through the toothing of the gear element. The actuation element drives and blocks the gear element by engaging into its toothing. The drive shaft comprises two discontinuous segments connected by the actuation element. The actuation element comprises pins located between, parallel to and separate from the two discontinuous segments, and adapted to engage with the toothing of the gear element to drive or block it.

The invention is considered to provide a less costly solution to compensate the oscillations caused by winds, hydraulic dampers, or other reasons.

The patent is a part of a family comprising 16 patent documents published between 2019 and 2023 in WO, CA, JO, AU, CN, IL, MX, BR, EP, US, CL, JP, and ZA.



Image from: US11689151B2

2a - module table; 3 - solar module; 4 - gear segment; 5 - drive shaft; 7 - cross brace; 8 - actuation element; 11 - toothing; 14 - vertical post; 15 - supporting plate; A - transverse axis; L - longitudinal axis

High costs of repair and replacement

Patent US11387773B2 granted to Tressbio Laboratory Co., Ltd. (JP) on 12.07.2022 discloses a solar battery panel heliostat apparatus. The panel is positioned on a frame supported by a support and rotated in a north-south and an east-west direction with the two rotational axes being in a skew positional relationship, and one of the axes passing through a top of the support (preferably, the azimuth angle rotation axis) and is above the other one. The panel is positioned between the two axes. The north-south rotation mechanism of the invention comprises a central crossbar passing through the support and movable in the east-west direction, a coupling member, and an actuator placed between the central crossbar and the frame to rotate the frame by extension and contraction. The north-south rotation truss structure comprises several coupling portions to connect the coupling member, the frame, the central crossbar, and the actuator. The east-west rotation mechanism of the invention comprises a rotating member rotatably coupled to the support on the one end, a coupling member connecting the rotating member and the frame on the other end, and an actuator coupling the other end of the rotating member and the support and rotating the frame by extension and contraction. The east-west rotation truss structure comprises several coupling portions to connect the rotating member, the support, and the actuator.

The authors mention that the prior art solutions are vulnerable to wind or other impacts.

The patent belongs to a family comprising 9 patent documents published in JP, WO, TW, CN, EP, and US, between 2019 and 2023.



Image from: US11387773B2

2 - solar battery panel; 2A - panel surface; 4 - elevation angle rotation axis; 7 - east-west rotation mechanism; 8 - support; 9 - north-south frame members; 10 - east-west frame members; 11 - support body; 12 - support plates; 13 - east-west rotating member; 14 - coupling member for east-west rotation; 15 - actuator for east-west rotation; 21 - central crossbar; 22 - north-south rotation; O,P,Q - truss structure

In the analysis of inventions from the present collection of documents, it was uncovered that, in the majority of cases, inventions related to solar tracking mechanisms additionally can be attributed to Flat-panel trackers, Tracker support structures, and Dual-axis trackers. Trackers for single-axis solutions and specifically for concentrating solar devices appear in lesser amount, although can still be widely met in the collection of inventions.

More detailed information about inventions in the field of solar energy, and patent research methodology can be found on aenert.com, in SOLAR ENERGY. Solar Trackers. Extended patent report. June 2022, and CONCENTRATED SOLAR POWER. Energy Storage. Patent Database. May 2022.

By the Editorial Board