RESEARCH THE ACCURACY OF MODELING POWER LOSSES IN POWER DIODES AND TRANSISTORS

The methodology for modeling static and dynamic power losses in power IGBT and MOSFET transistors in the Matlab and Multisim software environments is given. It is shown that when modeling switching processes in power transistors, Matlab / Simulink does not allow determining the dynamic components of power losses, namely, the energy of turning on the transistor, the energy of turning off the transistor, as well as the recovery energy of power diodes. At the same time, the simulation of static power losses of power diodes and transistors in Matlab/Simulink is carried out with a significant error due to incorrect representation of the current-voltage characteristics. It is shown that for a more correct and accurate simulation of the operation of power transistors, including power losses in power switches, it is more appropriate to conduct simulations in the Multisim software environment, which takes into account more than 47 parameters during simulation, including temperature characteristics, parasitic input and output capacitances and inductances, nonlinearities of current-voltage characteristics and others. In Multisim, a circuit of a half-bridge inverter with power MOSFETs controlled by the IR2104PBF driver has been developed. It is shown that the switching of power transistors is significantly influenced by the parameters of the driver microcircuit, namely the size of the storage capacitor of the driver, as well as the value of the active resistance of the gate resistor. It is shown that the simulation in Multisim correctly displays the transient processes of turning on and off power transistors and reverse recovery of diodes, which allows determining the dynamic losses of power transistors and power diodes.