Damping for Wind Turbine Electrically Excited Synchronous Generators

Abstract

-The electrically excited synchronous generator (EESG) is applied in wind turbine systems recently. In an EESG control system, electrical torque is affected by stator flux and rotor current. So the control system is more complicated than that of the permanent-magnet synchronous generator (PMSG). Thus, the higher demanding of the control system is required especially in case of wind turbine mechanical resonance. In this paper, the mechanism of rotor speed resonant phenomenon is introduced from the viewpoint of mechanics firstly, and the characteristics of an effective damping torque are illustrated through system eigenvalues analysis. Considering the variables are tightly coupled, the four-order small signal equation for torque is derived considering stator and rotor control systems with regulators, and the bode plot of the closed loop transfer function is analyzed. According to the four-order mathematical equation, the stator flux, stator current, and electrical torque responses are derived by torque reference step and ramp in MATLAB from a pure mathematical deduction, which is identical with the responses in PSCAD/EMTDC simulation results. At last, the simulation studies are carried out in PSCAD software package to verify the resonant damping control strategy used in the EESG wind turbine system.

Modeling and Simulation of the Anticipated Effects of the Synchronous Condenser on an Electric-Power Network with Participating Wind Plants

“…These variable-speed wind plants are decoupled from the corresponding electricity grid by power electronic converters. Different from synchronous generators, some types of wind plants are not able to play a part in frequency control activities such as inertia and governor response after a disturbance [33][34][35][36][37]. Although several control methodologies have been developed to allow Type-3 and Type-4 wind plants to be used for frequency regulation [38,39], such solutions are still not mandatory and normally do not operate for the Type-3 wind plant.…”

Wind energy conversion technologies and engineering approaches to enhancing wind power generation: A review

“…Besides, the field winding result in power losses, and, thus deteriorating the system performance. Furthermore, the cons and pros of DD-EESG are briefly summarized as follows [ 9 , 14 , 93 ]: Full-scale PEC allows it to completely handle the frequency and amplitude of the voltage on the machine side. Relatively generates high electrical power compared DFIG WECSs.…”

“… [ 105 ] Based on EESG technology Optimizing design Developing the robust control system design under the consideration of the wind turbine mechanical resonance, and by implementation the resonant damping control strategy for rotor speed and torque. [ 14 ] Enhancing low voltage ride through (LVRT) based on the provision of: active power in proportion to the voltage retained during voltage dip, and maximum reactive current until the voltage starts recovering. [ 93 ] …”

“…A severe three-line-to-ground fault [ 104 ]; and braking chopper (BC) [ 105 ] schemes were also implemented to smooth the operations of PMSG-based WECS. On the other hand, only few studies were recently introduced based on the design optimization of EESG wind power generation system, and two of them are similarly presented based on [ 14 ], and [ 93 ].…”

“…Hence, the optimization of the electrical components of PMSG-based WECS is one of the major themes of the recent and future research studies in the field of wind power engineering [ 13 ]. In the same time, EESG-based WECS is currently under continuous research studies for the better enhancement of its design efficiency in terms of cost, size, and weight though it is relatively less popular due to its cumulatively compromised performance in wind energy harvesting [ 9 , 14 ].…”