This thesis is about designing and building an intelligent battery charger, which shall be able to charge the most common types of batteries. During the process of implementation I have used digitally controlled synchronous Step-Down DC/DC converters. My work also contains a hardware and an embedded software. The first step was about working out a detailed specification and determining the parameters and the limits of the power supply.
The footprints of the components were planned by standards, so that they can easily be soldered. I designed the necessary PCB, after which it was manufactured and the components were implanted. Firstly, I have examined the output of the auxiliary power supplies by using current limit from laboratory power supply. Right after that, the microcontroller got the first „Hello world” program, followed by the testing of the components. Some minor mistakes occurred, but all of them were successfully corrected. Communication with a PC and the data transfer are done via USB.
In the further parts of the thesis, the most common types of batteries are being described including the most important measurable parameters; namely, the capacity, the efficiency, the internal resistance, and the specifying principles. For a better understanding of the internal resistance, the two-parameter and four-parameter battery models are being described, and a precise description of the theoretical background of the design of DC/DC converters is also given.
Measurements were done with the finished hardware and some characteristics were defined, i.e. efficiency and output voltage range. Lastly, I have compared and presented the outcomes of the different battery tests.
The finalised intelligent battery charger can be used properly with almost all types of batteries, with specified voltage and current limit. As for the future, I intend to improve the control panel for PC and create a user interface for smartphone. A Wi-Fi modul can also be implanted to the PCB.