Research Of Reactive Power Control Based On Three-phase Grid-connected Inverter

The dependency upon new energy has become more and more serious with theincreasing critical situation of non-renewable energy, despite the utilization of newenergy has become widely spread in recent years, the cost of equipment ingrid-connected system remains expensive. Besides, new energy greatly relies onexternal environment, results in the equipment to transform the energy into net idle or inlow utilization, then improve the cost of power generation system. At the same time,due to the mass use of power electronics, low power factor and low efficiency become acommon occurrence in power grid.In order to improve the utilization rate of the grid-connected system equipmentsand quality of power-grid system. This paper realizes the reactive power compensationbased on tri-phase grid-connected inverter, improving the efficiency and quality of thegrid. The main contains are shown as following:1. Operating principle and the switching processes of tri-phase grid-connectedinverter is analyzed. And in order to realize the current control of the inverter, themathematical model in stationary frame and synchronous frame are established.2. Instantaneous reactive current detection method is used to detect the reactivecurrent of the load, and the method of tri-phase grid-connected inverter to export theactive and reactive current is analyzed. The voltage outer and inner current loop controlstrategy and PI+RP compound control algorithm are given to realize the control ofactive and reactive current.3.Combined with the mathematical model and control strategy, simulation model isestablished based on MATLAB/SIMULINK. Simulation results shows that the invertercould compensate reactive and transfer the active power at the same time, which ishelpful to power quality improvement.4. An experimental platform is built, realize the reactive current detection of theload and the control of the active current and reactive current, achieve the purpose of transferring the active power and compensate reactive current at the same time.