Research On Micro-sourse Inverter Based On Feeder Power-flow Optimization

As an important part of the Smart Grid, Microgrid becomes one of the hotspots nowadays, and the economic operation problem of microgrid has attracted great attention of researchers. Power flow distribution in the microgrid determines the economic load distribution, so power flow control has become an important aspect of research on micro planning and economic operation. At the same time, the operation characteristics of microgrid is based on the inverter interface, so the realization of power flow control and optimization of the microgrid needs to rely on the inverter control method. Based on the discussion of microgrid power flow analysis and power flow control, this paper conduct a related research on the control strategy of microgrid inverter based on the feeder power flow optimization, aiming at the microgrid with peer to peer control structure, and takes the total generation cost of power system and feeder losses as the objective function of the microgrid optimal power flow.Aiming at the control target of power generation cost optimization in the low-voltage microgrid, this paper established the generation cost function model of different micro power, put forward a Nonlinear Droop Control strategy based on the generation cost, and then realized the optimal power flow control of low-voltage microgrid based on generation cost. Based on high R/X ratio characteristics of low-voltage microgrid and the resulting loss of transmission line, this paper discussed the necessity and feasibility of microgrid feeder power flow control. In order to achieve the goal of optimization of feeder loss, the nearest distribution of the active power source for small autonomous microgrid with local load has been realized by using feeder power flow control(FFC) method. Meanwhile this paper put forward an optimal strategy combined with FFC and Nonlinear Droop control, then the generation costs of micro power and feeder transmission loss can be reduced through the rational allocation of the optimization weighting factor, thus realized the economic operation of micro grid based on power flow optimization.A microgrid experimental platform composed of three micro sources with DSP digital control has been built to verify the experimental platform for control strategy proposed in this paper. The experimental results show that the proposed strategy can effectively reduce the generation costs and feeder loss of the microgrid, and ensure the stability of the system at the same time. So the microgrid economic operation considered the generation cost and transmission loss can be achieved.