System-level Simulation of Transient Loads in HV/LV DC-DC Electric Vehicle Converter

LLC topology is proposed for powering low-voltage DC loads from a high-voltage battery. The simulation model of the HV/LV DC-DC converter is obtained in MATLAB/Simulink and parametric analysis of the output voltage during switch ON/OFF loads were carried out. The importance of connecting a low voltage battery on the load side in terms of drop/jump of the output voltage depending on the switching is observed by comparing the voltage indicator according to the standards for system testing. Different load power steps, power change trend (loading and unloading), as well as charging state of the battery were used as parameters of analysis. The responses of the output voltage in transient state were analyzed in terms of identifying the duration of the transient state as well as the maximum change in the instant values of the output voltage. The importance of the gain factor in the feedback loop of the control circuit at the duration of the transient state is indicated. The measurement of the AC component of the output voltage was carried out on the Infineon EVAL-2ED2101-HB-LLC 200W board in order to evaluate the simulation results.