The thesis addresses design and development of a solar simulator with LEDs and illuminated area of 30 cm x 30 cm. In the beginning of the thesis we explain the need for the system for characterisation of solar cells and panels, introduce standardisation in this field and few examples of commercial solutions. Then we focus on the development of our system. The thesis from Žiga Rojec  which defines theoretically optimal positions and relative power outputs of LEDs, was used as the starting point. With use of various optimisation tools non-uniformity of 0,9 % was reached. Our goal for the whole system is to reach non-uniformity below 2 %.
Since we want to achieve this high non-uniformity goal, we have to drive and compensate each LED channel individually. For our system to be as cheap and simple as it is possible we don't achieve correct light spectrum, as need for that can be avoided. All the LED channels are driven by the use of microcontroller.
Final result is a working solar simulator, with spatial non-uniformity of 1,9 % which is capable of constant illumination. Measured non-uniformity is strongly dependent on radiation pattern of an LED as well as on the reference sensor used. Light rays are not parallel to each other.