Sunreign Reference: Some patents

Some patents

Motor control
Motor control dc
Tracking head
Heliostat field (can't be new)
Rim Driven

Pic hardware

Heliostat Controllers

The basic two types of heliostats are tracking and reflecting. These two types pose different requirements on the control system. In the case of tracking there needs to be a feedback loop between the panel orientation and the sun position. In the case of reflecting the relationship between the mirror orientation and the sun position is more complicated. Both tracking and refelcting can also be achieved by a precise time piece (afer all the sun's position determines the time of day).

A good tool to do any tracking work is a microcontroller. Microcontrollers are cheap (a few bucks) and have a lot of usefull features, reducing the need for components and simplifying electronics design. One can drive up to 36 volt and on amp using ICs on a simple board.

Tracking

As said a tracking controller has to create a feedback loop between the panel (for which it is mostly used) and the sun (light sensors). There are severla ways of measuring light intensity and the light intensity differential necessary for tracking.

You can find a number of tracking controllers here.

Pic Microcontrollers

One of the more popular microcontrollers is the pic controller of Microchip inc.. It can be coded in C or Basic and there is the easy to use Picaxe platform one can use.

Features
- 10 to 12 ADC converters for measuring light intensity
- I2C interface capability for interfacing with other sensors and clock
- Binary output channels for controlling H-bridge motor controlers or stepper motors
- PWM motor signal output
- Servo control output
- Serial output
- Low power modes

Prototypes

2-Axis with time

Above prototype uses a 28x2 picaxe mircocontroller. It drives the 12 volt motors with an L2930 H-bridge chip. This chip takes logic input from the picaxe which allows you to direct the dc motors in any direction.

It has a RTC clock to drive the position of the motor. It also has analog inputs meant either for watching what the mirror is doing or tracking the light of the sun.

I added a tricolor LED for indicating movement direction (can be hard to spot with slow moving motors) and other signals.

The buttons allow me to control the motors manually.

Below a rough schematic..

One axis with sensor

his one axis tracker is based on a picaxe 14m or 20 controller. It is the basis for a 2 axis unit that is both cheap and easy go make. It is combinde with the 293D chip for motor control up to 36 V and 1 Ampere.

The sensor is a LDR resistor in the low kOhm range. its output is fed into the AD converters of the picaxe chip. A stereo plug was used to connect the sendor. Some code drives the motor. There can be several options on how to do that, and that will be subject to more testing.

Here the test rig for the 1-axis heliostat controller.

A/D to serial

using a picaxe O8M2 more on the o8m2 here.

Sunreign Reference : HeliostatDIYController