High power isolated DC-DC converter design, modelling and control

The rapidly developing technology and the necessity of power control progressing in parallel with this technology is constantly increasing. DC-DC converters are the first method that comes to mind in order to best manage the power control necessity. Such elements have a wide range of uses such as renewable energy systems, new generation welding machines and motor applications. DC-DC converters needed from homes to industry differ according to the power levels used and the desired protection type. DC-DC converters respond to high or low power necessity in an isolated or non-isolated manner. DC-DC cenverters are basically composed of analog circuit elements. Due to the internal structure of the analog circuit elements and the material from which they are produced or disruptive environmental effects, the desired output voltage and current values may not be consistent. Also, considering the whole converter topologies, many undesirable losses occur. Think about all this effects, control of the converter becomes very critical. Converter control methods are divided into two types called as current mode control and voltage mode control, basically. Current mode control includes two nested control loops. Due to this structure, robustness and dynamical behaviour of system are getting better. The inner control loop of the current mode control method is current, and the outer control loop is voltage. The most used method to control the voltage is PID, considering its simple and inexpensive sutructure as well as the ease of use. PID method is based on error analysis and requires the measurement value taken continuously from the converter output. PID method is used in different types. The most used in converter systems is the PI method due to the nature of the converter systems. Current mode controllers are also divided into two method. One of them is the peak current mode control and the other is the aveerage current mode control method. Both methods have pros and cons compared to each other. Within the scope of study, as a first choice for high power systems, full-bridge converter will be designed and critical element selections will be made. Full-bridge converter will be handled at the system level and small signal analysis will be made in accordance with the current mode control and the transfer function will be created. Then, the simulation study of the full-bridge converter whose controller will be designed will be completed using the PSIM program and the results will be examined.