Research On Power Coordination Control Of Multi Inverters In Controllable Microgrid

With the emergency situation of global energy and increased environmental pollution, the distributed generation of clean energy, such as solar energy and wind energy, has attracted wide attention. Different distributed generation units are integrated into the microgrid, which can provide high quality power supply for local load. Microgrid not only has the advantages of distributed generation, but also has its own superiority. How to realize the coordinated control of power according to the local load demand and its own power generation when there are multiple distributed generation units in the microgrid, is the main research content of this paper.The working principle of UPC control and FFC control of distributed generation unit is described in this paper. A hybrid microgrid control structure is adopted in the condition of multiple DGs in the microgrid. The active power and frequency characteristics of the structure is also presented. The validity of this control structure is verified through theoretical analysis and simulation study in microgrid grid connected mode and islanded mode.A coordinated control strategy of active power is proposed in this paper, which is based on the hybrid control structure of microgrid. In this kind of control structure, the power flow between the microgrid and the grid can be kept constant when the microgrid is connected to the grid, and the frequency of the system is not affected by the load change in islanded operation. Not only the problem of power demand for the DG of peak load is solved effectively, but also the using efficiency of the DG is improved when changing the given value of the power of the DG in UPC control mode.The reactive circulation between DGs is caused by the difference of line impedance and local load when there are more than one DG in the microgrid. More seriously, the reactive power will be imbalanced when the reactive circulation occurred. If the reactive circulation is too heavy the line loss will be increased and even the inverter will be damaged. In order to solve the above problem, a reactive circulation suppression strategy, which suitable for microgrid connected mode and islanded mode, is proposed in this paper. The reactive circulation between multip DGs will be reduced and the stability of the system improved, when the proposed strategy is applied.A simulation platform is built in MATLAB/Simulink to verify the correctness and effectiveness of the proposed control strategy based on the above control strategies. The hardware of the system is introduced briefly, and the software design of the experiment is completed in TMS320FDSP2812. The feasibility of the control strategy of active power coordination control and reactive power sharing is verified by experiments.