Multi-pole permanent magnet synchronous generator wind turbines' grid support capability in uninterrupted operation during grid faults

Power system transient stability enhancement using direct drive wind generators

“…2 shows the drive train system for stability analysis considering severe network disturbances. In [4], it is stated that for such study, the drive train system must be approximated by at least a two-mass model. In the wind turbine integration studies, it is common to define the wind turbine mechanical power output as [7] In the fully rated converter wind generation, the speed control does not only depend on the generator, but also on the wind turbine drive power characteristics [18], so integrating the two parts is important for dynamic study of the machine.…”

“…Fig. 3 presents the pitch control system using a PI controller with anti-wind-up [4,19]. Its function is to control the generator speed by controlling the pitch angle of the blade and its rate-of-change such that over speeding of the wind turbine can be avoided.…”

“…4). This inverter is responsible to maintain the DC-link voltage, V DC, at constant value and control the flow of reactive power, Q grid , to the grid [4,20,21]. The var/voltage control for this study is built based on [19].…”

“…The tip speed ratio λ is expressed as [7]: Theoretically, full converter based wind turbine can ride through any grid faults (symmetrical or unsymmetrical) as the generator is fully decoupled from the grid through the grid side inverter. The reactive power exchange merely depends on the characteristic of the grid side converter and not on the generator properties [4,25]. Therefore, capability of the P machine to inject reactive power is utilized at the grid side converter.…”

“…Implementation of grid codes worldwide has been reported in various works and mostly suggested the utilization of variable speed generators such as DFIGs [2,3] and full converter based wind generation systems [4][5][6][7]. However, fixed speed generator are still contributing about 20% to 30% of global wind capacity [8], which mostly were installed in the 1980s to 1990s.…”