Study On PID Control Strategy Of Offshore Wind Power Grid Connection Base On VSC-HVDC

As the wind resource of random and the scale of the offshore wind farms expanding larger, the impact of the offshore wind turbines connecting into the net on power quality must be paid sufficient attention. But with the development of AC power system, its inherent shortcomings gradually appear. Because of the communication cables on the transmission capacity constraints, large-scale offshore wind farm whose rated capacity is hundreds of megawatts. So it can be considered to base on the voltage source converter (VSC) technology, HVDC Light (HVDC) transmission mode.Voltage source converter based HVDC transmission is the technology based new DC transmission technology, which is a form of controlled shutdown devices (such as IGBT, etc.) and pulse width modulation. Voltage source converter based HVDC (VSC-HVDC) power system is in the broad application prospects, so the control of wind farm based on VSC-HVDC was studied in this paper, the main contents include: compare the several offshore wind power technology with emphasis on the principle of VSC-HVDC technology analysis, establish the mathematical VSC-HVDC model and do the decoupling analysis, design of the control system base on the mathematical model and the principle of PID control strategy, and set up the simulation model of this system in Matlab/Simulink, do the work of commissioning, and the optimization of PID parameters, then analysis the final waveform diagram. The simulation result show:the VSC-HVDC system quickly into a stable condition under our design control system, when the condition is changed, the system more quickly follow the set value into a new condition. The simulation results verify the effective of the control system.