The Research Of Microgrid Comprehensive Control Strategy

Microgrid not only can show the advantages of distributed generation, but also can reduce the impact of distributed generation on the grid, It integrates a variety of dispersed distributed generation into a network, and make the voltage and energy within the network for unified management and scheduling, to become a novel power system structure.Firstly, the essay analyzes the principle and characteristic of the tri-phase full-bridge inverter, and obtains a discrete average state-space model. Taking into account deadbeat control strategy and load current as additional instruction, it proposes an improved double loop control strategy, which is based on traditional methods of voltage and current loop control. The simulation results show that the improved double loop control strategy can track reference instruction timely, dynamic response capability fast, and has good stability.Then analyzes the design method of PQ controller and Vf controller, builds simulation model and the effectiveness of this control strategy is verified by changing of the reference power or the reference voltage or the load, builds the microgrid master-slave control strategy simulation model, the Vf controller can track the reference voltage timely, ensure stability of the voltage and frequency of islanded microgrid; in grid connected mode, PQ control strategy can control output power to maintain their stable operation at a set value.Then the essay analyzes the droop control strategy and inverse droop control strategy, and establishes simulation model, the effectiveness of the two control methods are verified by changing load, then builds the microgrid peer to peer control strategy simulation model, the droop controller and inverse droop controller can ensure the stability of microgrid.Finally, because of the shortage of traditional droop control method, an improved droop control with a proportional-integral-derivative(PID) structure is proposed. When the voltage and frequency varies, the PID parameters are optimized using the Neural Networks technology, then a new droop controller based on single neuron adaptive PID control is designed, establishes simulation model, compared with the traditional droop control, whether steady-state operation or system disturbance occurs, the controller is able to reflect the sagging is robust, good tracking performance advantages of rapid dynamic response.