Drive-system protection arrangements for photovoltaic trackers

1 . A method of operating a solar energy system, the solar energy system comprising a photovoltaic (PV) assembly defining a mechanical pivot range, a drive system comprising a pivot-wheel assembly and a drive-system protection arrangement, the method comprising:

rotating the pivot wheel assembly towards a limit of the defined mechanical pivot range of the PV assembly, wherein (i) the PV assembly comprises a frame subassembly and an array of PV panels joined thereto and pivotable therewith about a longitudinal axis of the PV assembly, (ii) the drive system further comprises a motor assembly including an electric motor and a drive-system controller, (iii) the pivot-wheel assembly of the drive system is arranged to transfer a torque from the electric motor to the frame subassembly, (iv) the pivot-wheel assembly comprises a drive chain joined to a hoop portion at two opposing coupling points defining respective limits of the mechanical pivot range of the PV assembly; and (v) a drive-system protection arrangement comprises:

A. a pair of spaced-apart tab portions comprising respective sensor targets, joined to the hoop portion and circumferentially displaced from the two opposing coupling points, and

B. a sensor in electronic communication with the drive-system controller and operative to send a signal thereto indicating detection of a proximate presence of one of the sensor targets;

receiving, by the drive-system controller and from the sensor, the signal indicating the detection of the proximate presence of one of the respective sensor targets of the pair of spaced-apart tab portions; and

responsively to receiving the signal, calibrating an angular orientation of the PV assembly.

2 . The method of claim 1 , wherein the respective sensor targets comprise magnets, and the sensor comprises a magnetic sensor.

3 . The method of claim 1 , wherein the respective sensor targets comprise a metal or metal alloy, and the sensor comprises an induction sensor.

4 . The method of claim 1 , wherein the sensor comprises an ultrasonic sensor.

5 . The method of claim 1 , wherein the sensor comprises an optical sensor.

6 . The method of claim 5 , wherein the respective sensor targets comprise markings or reflectors.

7 . The method of claim 1 , wherein the drive-system protection arrangement is configured so that the signal is sent before the pivot wheel is rotated to a limit of the mechanical pivot range.

8 . The method of claim 1 , wherein the drive-system controller is programmed to receive the signal and perform at least one of the following in response thereto:

i. stopping the rotating of the pivot wheel before reaching the limit of the defined mechanical pivot range, and

ii. slowing the rotating of the pivot wheel before reaching the limit of the defined mechanical pivot range.

9 . The method of claim 1 , wherein in response to receiving the signal, one of the following is performed:

i. stopping the rotating of the pivot wheel before reaching the limit of the defined mechanical pivot range, and

ii. slowing the rotating of the pivot wheel before reaching the limit of the defined mechanical pivot range.

10 . The method of claim 9 , wherein the stopping and/or slowing is performed following a predetermined time interval after the receiving of the signal, the predetermined time being based upon at least one of: a current rotational or angular speed of the hoop portion, and a circumferential distance between the one of the spaced-apart sensor targets and the limit of the defined mechanical pivot range.

11 . The method of claim 9 , wherein the electric motor comprises a stepper motor, and the rotating is stopped or slowed after a predetermined number of motor steps following the receiving of the signal, the predetermined number being based upon at least one of: a rotational or angular speed of the hoop portion and a circumferential distance between the one of the spaced-apart sensor targets and the limit of the defined mechanical pivot range.