US-20260128709-A1 - COUNTERBALANCE ASSEMBLIES IN PHOTOVOLTAIC SOLAR TRACKERS

US20260128709A1US 20260128709 A1US20260128709 A1US 20260128709A1US-20260128709-A1

Abstract

A counterbalance assembly in a photovoltaic tracking system may include a top bracket secured to a torque tube such that the top bracket rotates with the torque tube about an axis of rotation between a first rotational limit in a first direction and a second rotational limit in a second direction. The assembly may include a bottom bracket secured to a column supporting the torque tube and a stretchable member with a top end connected to the top bracket and a bottom end connected to the bottom bracket. The assembly may include a means for limiting a restorative force applied by the stretchable member to less than a threshold level while the torque tube is between the first and second rotational limits. The means may include a pin-and-slot connection in the top and/or bottom brackets or a linkage between the stretchable member and the top and/or bottom brackets.

Inventors

Kevin Krautbauer
Benjamin C. de Fresart

Assignees

ARRAY TECH, INC.

Dates

Publication Date: 20260507
Application Date: 20251030

Claims (20)

1 . A counterbalance assembly in a photovoltaic (PV) tracking system, the counterbalance assembly comprising: a top bracket configured to be secured to a torque tube such that the top bracket rotates with the torque tube about an axis of rotation between a first rotational limit in a first direction and a second rotational limit in a second direction; a bottom bracket configured to be secured to a column supporting the torque tube; a stretchable member having a top end and a bottom end, the top end being connected to the top bracket and the bottom end being connected to the bottom bracket; and means for limiting a restorative force applied by the stretchable member to the torque tube to less than a threshold level while the torque tube is between the first and second rotational limits.
2 . The counterbalance assembly of claim 1 , wherein the first and second rotational limits are the same.
3 . The counterbalance assembly of claim 1 , wherein the first and second rotational limits are different and the first rotational limit is larger than the second rotational limit.
4 . The counterbalance assembly of claim 3 , wherein the means for limiting only limits the restorative force applied by the stretchable member to the torque tube in the first direction.
5 . The counterbalance assembly of claim 1 , wherein at least one of the first rotational limit or the second rotational limit exceeds 70 degrees.
6 . The counterbalance assembly of claim 1 , wherein the stretchable member is a spring.
7 . The counterbalance assembly of claim 1 , wherein the threshold level of force is less than 1000 N-m.
8 . The counterbalance assembly of claim 1 , wherein the means for limiting comprises: a pin and slot connection where the stretchable member is connected to a pin that is positioned within a slot in at least one of the top bracket or the bottom bracket, wherein the pin and slot connection allows a connection point between the stretchable member and the at least one of the top bracket or the bottom bracket to move within the slot such that a rate at which the restorative force increases as the torque tube rotates toward the first or second rotational limits is reduced.
9 . The counterbalance assembly of claim 1 , wherein the means for limiting comprises: a linkage positioned between the stretchable member and at least one of the top bracket or the bottom bracket, wherein the linkage is secured to the at least one of the top bracket or the bottom bracket through a pivot joint such that, as the torque tube rotates toward the first or second rotational limits, a connection point between the stretchable member and the linkage pivots about the pivot joint in a rotational direction that is opposite to a rotational direction of the torque tube.
10 . A counterbalance assembly in a photovoltaic (PV) tracking system, the counterbalance assembly comprising: a top bracket configured to be secured to a torque tube such that the top bracket rotates with the torque tube about an axis of rotation between a first rotational limit in a first direction and a second rotational limit in a second direction; a bottom bracket configured to be secured to a column supporting the torque tube; and a stretchable member having a top end and a bottom end, the top end being connected to the top bracket and the bottom end being connected to the bottom bracket, wherein at least one of the top bracket or the bottom bracket includes a pin that is positioned within a slot and the stretchable member is connected to the at least one of the top bracket or the bottom bracket through a pin and slot connection; wherein the pin and slot connection allows a connection point between the stretchable member and the at least one of the top bracket or the bottom bracket to move within the slot such that a rate at which a restorative force is applied by the stretchable member is reduced as the torque tube rotates toward the first or second rotational limits.
11 . The counterbalance assembly of claim 10 , wherein the slot is symmetric about a vertical axis.
12 . The counterbalance assembly of claim 10 , wherein the slot is asymmetric about a vertical axis.
13 . The counterbalance assembly of claim 10 , wherein the stretchable member is a spring.
14 . A counterbalance assembly in a photovoltaic (PV) tracking system, the counterbalance assembly comprising: a top bracket configured to be secured to a torque tube such that the top bracket rotates with the torque tube about an axis of rotation between a first rotational limit in a first direction and a second rotational limit in a second direction; a bottom bracket configured to be secured to a column supporting the torque tube; a stretchable member connected at a top end to the top bracket and at a bottom end to the bottom bracket; and a linkage positioned between the stretchable member and at least one of the top bracket or the bottom bracket, wherein the linkage is secured to at least one of the top bracket or the bottom bracket through a pivot joint such that, as the torque tube rotates toward the first or second rotational limits, a connection point between the stretchable member and the linkage pivots about the pivot joint in a rotational direction that is opposite to a rotational direction of the torque tube.
15 . The counterbalance assembly of claim 14 , further comprising one or more stops which prevent the linkage from moving in the rotational direction of the torque tube when the torque tube rotates past a rotational threshold.
16 . The counterbalance assembly of claim 15 , wherein a first stop is included on a first side of the linkage and a second stop is included on a second side of the linkage.
17 . The counterbalance assembly of claim 15 , wherein the rotational threshold is less than 45 degrees in a counterclockwise direction of rotation and/or less than 45 degrees in a clockwise direction of rotation.
18 . The counterbalance assembly of claim 14 , wherein the stretchable member is a spring.
19 . The counterbalance assembly of claim 14 , wherein: the linkage is positioned between a top end of the stretchable member and the top bracket, the top end of the linkage is secured to the top bracket through the pivot joint, and the connection point is between the top end of the stretchable member and a bottom end of the linkage, wherein: the connection point rotates in a clockwise direction as the torque tube rotates in a counterclockwise direction and rotates in a counterclockwise direction as the torque tube rotates in a clockwise direction.
20 . The counterbalance assembly of claim 14 , wherein: the linkage is positioned between a bottom end of the stretchable member and the bottom bracket, the bottom end of the linkage is secured to the bottom bracket through the pivot joint, and the connection point is between the bottom end of the stretchable member and a top end of the linkage, wherein: the connection point rotates in a clockwise direction as the torque tube rotates in a counterclockwise direction and rotates in a counterclockwise direction as the torque tube rotates in a clockwise direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 63/715,341, entitled COUNTERBALANCE ASSEMBLIES IN PHOTOVOLTAIC SOLAR TRACKERS, filed Nov. 1, 2024, which is incorporated by reference in its entirety. FIELD The present disclosure relates to solar energy production and more particularly to counterbalance assemblies for decreasing the moment force exerted on a torque tube at high tilt angles. BACKGROUND Solar installations including solar farms, photovoltaic (PV) plants, solar tracking systems, fixed solar systems, and other PV systems often include large numbers of PV modules that collect sunlight and generate energy. In solar tracking systems, PV modules are supported by horizontal support structures, or torque tubes, which rotate so that the PV modules may be oriented at various tilt angles to follow a position of the Sun as it moves throughout the day. PV modules are often left vulnerable to the elements because of the tilt angles at which the modules operate. As most PV modules utilize glass to encase the PV cells, hail is a significant threat to solar installations. For example, hail may shatter the glass, damage the PV cells, and cause unseen damage that may reduce the effectiveness of the PV module. One technique for mitigating hail damage is to position the PV modules at steeper tilt angles—or stow the PV modules at higher angles—during a hailstorm. PV modules that are positioned horizontally (with 0° tilt angles) are subject to direct or nearly direct impact from falling hail and the forces that result. Stowing the modules at steeper angles may reduce the impact force of the hail relative to horizontal tilt angles thereby creating glancing blows instead of direct impacts. A steeper tilt angle results in a less direct impact from falling hail. Additionally, stowing the modules at higher angles reduces the effective area of glass that is exposed to the hail. Thus, stowing the modules at higher angles may reduce the extent of damage that may be caused by a hailstorm and may render the PV module more effective over a longer period of time. In many solar tracker systems, counterbalance assemblies may create forces that assist the PV modules in returning the PV modules to lower tilt angles or horizontal from stow configurations. As the torque tube is rotated, a moment force may be created about the center of the rotation axis, which increases as the tilt angle increases. The amount and direction of this moment force is determined by the weight of the PV modules, which creates a rotational force on the torque tube in the direction of the PV modules, and by the counterbalance assembly, which creates a rotational force in an opposite direction. As the tilt angle increases, the moment created by the counterbalance assembly also increases. At steep tilt angles, however, (such as hail-stow angles) the moment load created by the counterbalance assembly may exceed the rotational force created by the PV modules. While the torque tube rotates to stow the modules, the counterbalance assembly may effectively be influencing or pulling the modules back toward horizontal. The amount of pull created by the counterbalance assembly at these steep tilt angles may be sufficiently strong to damage components of the tracking system and/or prevent the tracking system from achieving a hail-stow position, leaving the PV modules at a more shallow angle and more vulnerable to hail damage. Accordingly, there is a need for a counterbalance assembly that reduces the rate at which a restorative force created by a counterbalance assembly increases when PV modules are stowed at steeper angles. As a result, steeper tilt angles may be achieved, and PV modules may suffer less damage during a hailstorm. The subject matter claimed in the present disclosure is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example technology area where some embodiments described in the present disclosure may be practiced. SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Exemplary embodiments of the present disclosure address problems experienced in solar tracking systems, including problems associated with stowing PV modules at higher tilt angles. Embodiments disclosed herein address these issues by providing a counterbalance assembly with a means for limiting a restorative force applied to the torque tube to less than a threshold level while the torque tube is between the rotational limits of the PV tracking system, which may allow for hi