Three Phase Grid Connected Photovoltaic System with Active and Reactive Power Control Using “Instantaneous Reactive Power Theory”

Abstract

In  this paper,  a  photovoltaic  (P/V)  system,  with maximum  power  point  tracking  (MPPT),  connected  to  a  three phase grid is presented. The connection of photovoltaic system on  the  grid  takes  place  in  one  stage  using  voltage  source inverter  (VSI).  For a better  utilization  of the photovoltaic system,  the  control  strategy  applied is based  on  p-q  theory.According  to  this  strategy during  sunlight  the  system  sends active  power to  the  grid  and at  the  same  time  compensates  the reactive  power  of  the  load.  In  case  there  is  no  sunlight  (during the   night   for   instance),    the   inverter   only compensates   the reactive power of the load. The advantage of this strategy is the operation  of  the  photovoltaic  system  the  whole  day.  In  this paper the  p-q theory  is  proposed,  which does not  demand  the use of PLL and introduces simple algebraic calculations.