The DC electronic load is a laboratory test instrument that provides a wide range of additional options in the test environment. It is used to test power supplies, rectifiers, solar cells, etc., as any adjustable load. In addition to adjustable load, the instrument also measures voltage, current and power and when enriched with software, also calculates energy, etc. Naturally, all this leads to great complexity and higher price, so the thesis presents the theory of electronic load operation, which is then used to build a simple and affordable device with most of the functions offered by the commercial implementations.
The first step presents the selection of the implemented functions, followed by the design part, where individual parts of the electronic load are designed using simple structures, and then with the help of simulation, the operation is checked before the prototype is built. With the satisfactory results of the simulation, a prototype was made and functional tests with short measurements were performed, which showed inappropriate current measurement and regulation of the cooling system.
The next step was the second revision, where the errors were eliminated and optimized through simulation. After a successful simulation results, an improved printed circuit board was designed, where new components were used and a housing was built which encloses the prototype, the cooling system and the user interface.
Before the product testing, a calibration procedure was performed to ensure correct measurement and adjustment of the control loop. The measurements showed the linearity of the circuit measuring parts, and the accuracy within the desired current and voltage limits, and power ranges. The effectiveness of heat flow from the transistors to the heat sink and then out of the instrument was also checked.
After analyzing all the results, it was concluded that the goal of electronic load design and manufacture has been achieved. In addition, possible improvements such as more accurate measurement, change in current capacity and addition of major software functions such as external communication between the instrument and the computer are given.
|
