MODELING OF THE COMBINED ELECTRIC POWER SYSTEM OF A LOCAL OBJECT WITH MULTIFUNCTIONAL CONVERTER UNIT OF PHOTOVOLTAIC BATTERY

Abstract

The development of a detailed mathematical model of the system "network - multifunctional converter  unit  with  a  photovoltaic  battery  -  load",  which  will  allow  for  a  comprehensive  study  of  the processes in the system with an assessment of the efficiency of the unit. Synthesis of the structure of the model and the control system of the unit based on the analysis of processes in electrical circuits using computer simulation. Findings.  Dependencies  for  approximating  the  current-voltage  characteristics  of  a  photovoltaic battery.  The  use  of  a  standard  model  of  a  transformer  with  magnetic  circuit  saturation  as  a  nonlinear reactor is proposed. A model for determining power losses in semiconductor switches by the instantaneous values of currents and voltages and their catalog data. Originality.  The  mathematical  model  of  the  photovoltaic  battery  is  improved  according  to  the passport data with the introduction of the dependence of the open circuit voltage on the intensity of solar radiation. The structure of the control system with an internal current control loop and switching external
controllers  according  to  the  operating  modes  has  been  improved:  when  working  with  the  network  in  the "day" mode, it is the voltage controller of the photoelectric battery, in the "night" mode it is the inverter input  voltage controller; in  standalone  mode -  load voltage controller.  There  is  a justified  change  in  the settings of the current control loop and the modulation frequency in the standalone mode to eliminate the
growth of power losses in the switches.  Practical value. The obtained solutions are the basis for the design and analysis of indicators of multifunctional converting units for systems with renewable energy sources with improved energy efficiency.