Nested Loop Control of a Buck Converter under Variable Input Voltage and Load Conditions

Buck converters are widely used in industry, traction, and renewables. However, most of the researches in the control of these converters are devoted to low-power applications with discontinuous current mode, or use very complex control theory without taking into account current limit and external disturbances such as rapid input voltage and load current deviations. This paper proposes a nested loop control, which idea was taken from the motor drive control theory and implemented for the buck converter of auxiliary power supply of subway train. Simulation results are presented in the paper considering variation of the disturbances as well as inaccuracies of the sensors.