Simulation And Implementation Of Power Generation Control For Permanent Magnet Synchronous Machine Based Mechanical Elastic Energy Storage System

Recently,the increasingly scarce of traditional energy and environmental degradation have been promoting large-scale development of new energy,which increased propotion of new energy in grid.However,with intermittent and fluctuant characteristics,when connected into grid,large-scale wind power and photovoltaic power will bring great challenges to electric power system.Experience has shown that energy storage technology can ensure large-scale intermittent new energy to be smoothly connected into grid and help solve traditional balance problem of power supply and demand in power system.Therefore,inspired from energy storage principle of mechanical spiral spring,our team proposed a noval Mechanical Elastic Energy Storage?MEES?technology,in which spiral springs are sealed in energy storage box as energy storage components.By controlling special structural linkage energy storage box with large storage capacity and Permanent Magnet Synchronous Generator?PMSG?,energy starage and power generation will be implemented.MEES unit is the important implementation form of MEES technology,whose operation concludes two major processes of enegy storage and power generation.In this thesis,power generation control of MEES unit is studied.The main works of the thesis are as follows:?1?The main structure and working principle of MEES are introduced and the mathematical models of energy storage box,PMSG and converters are built.Based on the mathematical models,physical properties of MEES unit and difficulties in power generation contro lare analized,which help laid the foundation for subsequent sections.?2?In allusion to the simultaneous time-varying characteristics of power source torque and moment of inertia in permanent magnet synchronous motor based mechanical elastic energy storage system,a parameter identification and L₂ gain based backstepping control strategy is proposed.First,time-varyring moment of inertia and input torque are simultaneously identified through the least squares algorithm with forgetting factor.Then,on the basis of identification results and combining backstepping control and L₂ gain disturbance suppression method,a nonlinear backstepping controller is designed against identification errors and parameters perturbation.simulation results show that the outputs of PMSG can track the target values rapidly and the proposed strategy has a certain anti-interference ability.?3?By considering uncertainty of internal parameters of PMSG,generation control strategy with fully unknown unit parameters is studied and an adaptive backstepping control scheme via model reference adaptive system parameter identification is proposed.Firstly,Popov super stability theory based MRAS parameter identification is designed to identify the parameters of inductance and flux linkage for PMSG,and torque and moment of inertia for spiral spring respectively.Then,based on the identification results,through combination of adaptive control and backstepping control,nonlinear controllers are designed.Finally,simulation results validate the proposed scheme can achieve precisely speed tracking and rapidly dynamic response under the condition of fully unknown unit parameters.?4?Control strategy of grid-side inverter is studied and MEES unit experiment platform is constructed.By utilizing backstepping theory,closed loop voltage regulator and closed loop reactive power regulator are desiged to replace traditional PI controllers.Then based on the constructed MEES unit experiment platform,power generation control experiment is operated and the feasibility and effectiveness of proposed control schems in this thesis is verified.