Starter And Generator Control Of The Micro-Turbine Generation System

The rapid economic development in recent years has promoted the continuous growth of electricity demand,the environmental pollution and energy crisis caused by the continuous consumption of fossil fuels are also becoming increasingly prominent.The development of new energy and distributed generation technologies is receiving increasing attention.However,the distributed power source represented by the wind power and the photovoltaics has strong intermittent and instability characteristics,which makes the power quality of the distributed new energy power station poor and the light rejection rate and the wind abandoning rate are high,resulting in waste of resources.The Micro Turbine Generation System(MTGS)has the advantages of fast response,low emissions and high comprehensive utilization efficiency.It is very suitable for the task of peaking and frequency regulation in the new energy grid,which will help the new energy consumption.In this thesis,the start-up and power generation of the micro turbine generation system and the control strategy of the bi-directional converter in the heuristic smooth switching process is studied.Established a mathematical model of the micro turbine generation system.The control strategy of various operating conditions of MTGS start-up/power generation is proposed and carried out simulation verification.This thesis mainly includes the following content:During the start-up process of MTGS,the thesis proposes control strategies for machine side and grid side converters.Power supply from the grid to the permanent magnet synchronous motor via a back-to-back four-quadrant converter,realizing the start of the micro turbine.Specifically,it is proposed that the grid-side converter adopts vector control based on grid voltage orientation to achieve the effect of rectification and voltage stability.The machine-side converter adopts vector control based on the rotor flux linkage orientation,and drives the motor to the rated speed,thereby driving the micro turbine to start.In view of the power generation process of the MTGS,the rectification control strategy based on the rotor flux linkage of permanent magnet motor is proposed to maintain the stability of the bus voltage.At the same time,according to whether the system is connected to the grid,the grid-side converter adopts VF control of isolated network and PQ control in grid-connected state,and can realize the switching of the system's on-grid or off-network status.Based on the actual operating characteristics of the micro turbine generation system,this thesis proposes an integrated control strategy for MTGS start-up and power generation,and establishes the judgment logic of MTGS heuristic switching,which can realize the control of the MTGS start-up/power generation and smooth switching in two states.Modeling with Matlab/Simulink and verifying the control strategy of MTGS under different operating conditions,and the simulation results show that the proposed control strategy can realize the startup and power generation control of the MTGS.In the switching process between starter and generator,the bus voltage has a small impact and can quickly return to stability.And through the back-to-back four quadrant PWM converter to realize the power-direct-crossing conversion and the bidirectional flow of energy between the micro turbine generation system and the grid and verify the effectiveness of the adopted control strategy.