DPC-based control strategy of VSC-HVDC converter for offshore wind farm

DPC (Direct Power Control) is designed for the grid-connected VSC-HVDC system of offshore wind farm, which applies the virtual flux technology to calculate the system power. The AC voltage sensors and PLL are saved to increase system reliability and decrease cost. The power and virtual flux models of three-phase VSC are constructed to estimate flux and power. The voltage reference signal is directly calculated according to the error of power, and the SPWM wave is generated to replace the hysteresis control and avoid the PI parameter adjustment of internal control loop. The results of simulation with Matlab/Simulink indicate that, the converters at both sides can operate without AC voltage sensors, and the system needs less parameter adjustment and has fast response speed and high steady-state tracking accuracy.