Research On Virtual Inertia Optimization Control Of Direct-Drive Permanent Magnet Synchronous Wind Generator

With the rapid development of wind power generation technology,direct-drive permanent magnet synchronous wind generator(PMSG)which is a common type of wind power generation can transmit the captured wind energy to the power system.However,after the wind power is connected to the power grid on a large scale,a new problem that is different from the traditional power system emerges.Conventional direct-drive wind turbine has insufficient support capacity for system frequency,which may cause instability of the system frequency under disturbance.This paper introduces the PMSG model and the overall control strategy of PMSG system with virtual inertia,and analyzes the stability of PMSG system with drive shaft.Based on the conventional virtual inertia control,the adaptive virtual inertia control and the multi-objective model predictive virtual inertia control are proposed to improve the system frequency under disturbance.In the optimal control of virtual inertia based on adaptive control,this paper proposes three control strategies based on the existing methods: the improved bang-bang control,the power function control and the optimal control.The main purpose of those methods is to optimize the dynamic process in the disturbance process and to improve the frequency response.In order to analyze the stability of the PMSG system with adaptive virtual inertia,the paper Contains two different methods.Finally,a simulation platform of 2MW direct-driven wind turbine is built to verify the effectiveness of the control strategy.The optimal control of virtual inertia based on multi-objective model predictive control(MPC)applies the multi-objective regulation ability and efficient tracking ability of MPC,and it realizes the optimal control of current and frequency of direct-driven wind turbine through the establishment of the prediction model of the next moment.The extraction method and specific steps of each component are introduced in detail,and the weight coefficient is allocated reasonably according to different working conditions to improve the stability of direct-driven wind turbine.Finally,a simulation platform of 2MW direct-driven wind turbine and a 5k W experimental platform are built to verify the effectiveness of the control strategy.