servo controllers are getting less expensive - rapidly!

So.. an H Bridge Servo controller and a SOC Processor - can be built in two parts, very cheaply.

By the time the electronics are built, the cost between stepper and servo controllers can be very little... the SOFTWARE of a servo - is a lot more complex... but can be built as standardized modules - and then self adjust to the application... neat, hunh?

If I am building a motor application - say for a water irrigation system - I would absolutely favor a servo type application. Steppers are "start - stop" type motors - and servos allow for dynamic adjustment better... so a servo can be a lot more "friendly toward" power systems sourced electrically from wind or solar power systems.

You can pick a "power range" - say 1 - 5 hp - and do a system comparison for typical irrigation systems - and it will really show the difference.

Electronics cost is low - when all things are considered....

In case of stepper motor driven solar trackers, the movement of the tracker is not continuous, rather interrupted i.e. it moves by a certain step size, stops and after some time again rotates. This is because stepper motors have typical step sizes of 7.5 degrees and above. Which means an electrical signal to the motor makes the solar panel move by atleast 7.5 degrees. Now a 7.5 degree of rotation of the solar panel on the earth will have to correspond to a larger movement of the sun in the sky (see pic). So there is problem of small misalignment(which can cause some amount of significant power losses). Whereas in linear actuator driven solar tracker, the movement/rotation is much more continuous. So it can be said that a linear actuator driven tracker can more accurately mimic the synchronized "sunflower bud" movement than a motor driven one and hence minimize the power lost due to misalignment of the solar panel.

Shailesh Tripathy's answer is totally right. Linear actuators are well suit for solar tracking applications. Because; linear actuators prvide smooth tracking ability compared to stepper motor.

Linear actuators are typically slower, however it limits the angle of movement.

If you want to move dish/PV step motors will have to drive a gear drive or

one or more slewdrives.

See our solution and literature study in this document:

https://www.researchgate.net/publication/260844761_Automatic_positioner_and_control_system_for_a_motorized_parabolic_solar_reflector

Thesis Automatic positioner and control system for a motorized para...

gearing is wonderful.

Steppers work great and are easy to control. But servos can be much smaller and burn less energy overall.... that is a good thing...

I agree with Jerry Robinson, that servomotors are better than steppers because steppers consume power even when they are at rest. But servos require a special and sophisticated controller, often a dedicated module designed specifically for them. So a someone/startup company with low capital is unlikely to go for servos. So you can say that stepper and linear actuators are cost effective solutions. To choose between these one must take into perspective whether they require better control over the tracker or slow and smooth movement of the tracker.

servo controllers are getting less expensive - rapidly!

So.. an H Bridge Servo controller and a SOC Processor - can be built in two parts, very cheaply.

By the time the electronics are built, the cost between stepper and servo controllers can be very little... the SOFTWARE of a servo - is a lot more complex... but can be built as standardized modules - and then self adjust to the application... neat, hunh?

If I am building a motor application - say for a water irrigation system - I would absolutely favor a servo type application. Steppers are "start - stop" type motors - and servos allow for dynamic adjustment better... so a servo can be a lot more "friendly toward" power systems sourced electrically from wind or solar power systems.

You can pick a "power range" - say 1 - 5 hp - and do a system comparison for typical irrigation systems - and it will really show the difference.

Electronics cost is low - when all things are considered....

I just completed designing a tracking system using servos and an Arduino control module.

Have a look. I found the step of my servo sufficiently small.

Conference Paper A Cost-effective Microcontroller based Sensor for Dual Axis ...