Study and analysis on the control of SCIG and its responses to grid voltage unbalance

Investigation of Wind Farm Interaction with Ethiopian Electric Power’s Grid: A Case Study at Ashegoda Wind Farm

“…The other parts of the wind turbine structure, e.g. tower and the flap bending models do not have significant effect on grid interaction of wind farm [6].In most cases two-mass drive train model is used as it provides more accurate drive train dynamic responses and substantially improves simulation efficiency [7] 𝜔 𝑘 = 𝜔 𝑟𝑜𝑡 − 𝜏 𝑠ℎ𝑎𝑓𝑡 = 𝑐𝜔 𝑘 + 𝑘𝜃 𝑘 (5) Where: ω gen and ω rot are generator and rotor angular speeds respectively; θ k and ω k are the angles and angular speed differences between the two ends of the flexible shaft respectively; J rot is rotor inertia; τ rot and τ shaft are aerodynamic torques on low and high speed shafts respectively; k and c are the low speed shaft stiffness and a damping coefficient respectively; n gear is gear ratio which is 1:67 in this work as the wind turbines are gearless. Similar to aerodynamic model, Drive train model is implemented by DSL future of DIgSILENTPowerFactory.…”

“…The model is composed of two groups, i.e. the first is the voltage equations and the other is the flux ones [6]. { 𝜆 𝑑𝑠 = 𝐿 𝑠 𝑖 𝑑𝑠 + 𝐿 𝑚 𝑖 𝑑𝑟 𝜆 𝑞𝑠 = 𝐿 𝑠 𝑖 𝑞𝑠 + 𝐿 𝑚 𝑖 𝑞𝑟 𝜆 𝑑𝑟 = 𝐿 𝑟 𝑖 𝑑𝑟 + 𝐿 𝑚 𝑖 𝑑𝑠 𝜆 𝑞𝑟 = 𝐿 𝑟 𝑖 𝑞𝑟 + 𝐿 𝑚 𝑖 𝑞𝑠 (7) where subscripts 's' and 'r' refer to the stator and rotor sides respectively, subscripts 'd' and 'q' refer to the daxis and q axis respectively.…”

“…With respect to the reference frame oriented along the grid voltage vector position, the control enables the independent control of active and reactive power exchanges between the grid and the converter (Figure 6). The d-current is utilized to control the DC voltage and qcurrent to regulate the reactive power [6]. The grid side converter control contains two PI control loops in cascade:…”

PV and Wind Energy Conversion Exploration based on Grid Integrated Hybrid Generation Using the Cuttlefish Algorithm

“…It can be adopted to keep the DC link at a constant voltage [13][14][15][16][17], which will decouple the grid from power fluctuations caused by wind variations. The overall control method for the PMSG [1,4,[9][10][11][12] based wind energy power system is depicted in Figure 2. The reference torque is generated in a torque control scheme by measuring the generator speed.…”

Power Control of Wind Turbine Driven Permanent Magnet Synchronous Generator Using Maximum Power Point Tracking Algorithm

“…Due to the fixedspeed operation for constant speed turbines, all the variations in the wind speed are transmitted as fluctuations in the mechanical torque and then as fluctuations in the electrical power grid. This can be avoided by the use of variable-speed wind turbine and also the increased energy capture, operation at maximum power point, improved efficiency, and power quality [1]. Because of this reason, the wind industry trend is to design and construct variable-speed wind turbines.…”