Microgrid Optimization And Inverter Technology

With the increasing pursuit of quality of human life,intelligence has become the theme of future power grid.As the most typical smart grid,the microgrid has the advantage of self-regulatory functions to ensure the quality of electricity while maximizing the efficiency of alternative energy resources and reducing energy consumption to reduce emissions.Under the development tendency of smart grid and microgrid,this paper focuses on the research of the microgrid based on single-phase half-bridge three-level inverter and the EMS algorithms.The main work of this paper is shown below.This paper first studies the single-phase half-bridge three-level inverter.By the analysis of the topology and working principle of the single-phase half-bridge three-level inverter citcuit,the system transfer function is derived based on the unipolar modulation method.Then the corresponding controller is designed after the mathematical model of the inverter output to the load voltage established.And the parameters of the inner and outer rings are designed.Based on the description above,the hardware design and software design of the single-phase half-bridge three-level inverter are discussed in detail.The simulation of the single-phase half-bridge three-level inverter with resisters is presented at last.The harmonic analysis of the output voltage shows that the proposed method of this paper has obtained a relatively low voltage distortion rate,which verifies the correctness of the experimental scheme.Then this paper analyzes parallel power supply technologies.This technology within the microgrid generally includes constant power control when it is grid-tied and droop control when it is island.Because the main research of this paper is the microgrid under islanding mode,two distributed power sources in the microgrid are built using the Simulink module in MATLAB and two inverters are connected in parallel using the droop control strategy.Then the experiment is carried out with the same simulation parameters.By the analysis of the experiment results,the effectiveness of the proposed theory has been verifiedFinally,in order to solve the optimization problem of the management of microgrid group energy,this paper has proposed a rolling optimization algorithm.After having built up the constrained cost model for each energy unit in a microgrid,the proposed algorithm is optimal output sequence of controllable power source and battery in each dispatching cycle.And the operating cost of the whole microgrid has been reduced.Then,this paper establishes the energy cost constraint of the whole microgrids cluster based on the optimization of each microgrid,and establishes the optimization problem.By employing Alternating Direction Multiplier Method(ADMM),the proposed optimization problem has been solved to obtain the optimal output for each microgrid in the cluster.The simulation results show the feasibility of the proposed algorithm.