Abstract:

With the increase of wind power grid-connected capacity, the system inertia support capacity is insufficient, and the grid frequency instability is becoming more and more obvious. The virtual synchronous generator technology simulates the synchronous generator operation characteristics and becomes an effective solution. the direct-drive permanent magnet wind turbine of one of the mainstream models of wind farms as the research object is taken, and introduces the virtual synchronous control strategy in the grid-connected control to improve the equivalent inertia of the direct-drive permanent magnet wind turbine to deliver smooth power to the grid. And use the unit's own overspeed and pitch coordinated control to provide spare capacity, through the virtual synchronous generator's inertia response control link to increase the active output to improve the system’s primary frequency modulation capability. The simulation results show that the coordinated control strategy proposed here can make full use of wind turbine’s own load shedding operation and virtual synchronous generator technology, effectively improve the frequency stability and inertial support effect of the grid-connected system, which is conducive to the safe and stable operation of the power system.

Key words: Direct drive permanent magnet wind turbine, virtual synchronization control, spare capacity, inertia, primary frequency modulation