Increased penetration of wind energy systems has serious concerns on power system stability. In spite of several advantages, doubly fed induction generator (DFIG) based wind energy systems are very sensitive to grid d...Increased penetration of wind energy systems has serious concerns on power system stability. In spite of several advantages, doubly fed induction generator (DFIG) based wind energy systems are very sensitive to grid disturbances. DFIG system with conventional vector control is not robust to disturbances as it is based on PI controllers. The objective of this paper is to design a new vector control that is robust to external disturbances. To achieve this, inner current loop of the conventional vector control is replaced with sliding mode control. In order to avoid chattering effect and achieve finite time convergence, the control gains are selected based on positive semi-definite barrier function. The proposed barrier function adaptive sliding mode (BFASMC) is evaluated by testing it on a benchmark multi-machine power system model under various operating conditions. The simulated results show that the proposed method is robust to various disturbances.展开更多
High wind power penetration(WPP)is challenging system frequency stability.As a countermeasure,virtual inertia controls are introduced,utilizing kinetic energy(KE)stored in wind turbine generators(WTGs)for frequency re...High wind power penetration(WPP)is challenging system frequency stability.As a countermeasure,virtual inertia controls are introduced,utilizing kinetic energy(KE)stored in wind turbine generators(WTGs)for frequency regulation.Without restoration,generation efficiency of WTGs will be degraded after inertia contribution.To counter this issue,we propose an inertia control scheme of a doubly fed induction generator(DFIG),aiming at achieving dynamic inertia recovery regarding both KE and DC link energy.An asymmetrical droop control,referred to as the rate of change of frequency(RoCoF),is proposed for KE management.The upper boundary of droop gain is extended to give full play to converters and is revised,considering the system frequency state,to counter positive feedback issues induced by reversible gain regulation,which is restricted by KE to ensure stable operations as well.The inertial DC energy needed to cooperate with KE control regarding countering small fluctuations,is improved with an orderly recovery behavior.Case studies are conducted under dynamic wind conditions and the results indicate that with our proposed scheme,the ability of dynamic inertia recovery can be obtained,bringing DFIG higher generation efficiency and more adequate operation margin for sustained regulation.Essentially,the inertial frequency response and fluctuation suppression ability is well maintained.展开更多
文摘Increased penetration of wind energy systems has serious concerns on power system stability. In spite of several advantages, doubly fed induction generator (DFIG) based wind energy systems are very sensitive to grid disturbances. DFIG system with conventional vector control is not robust to disturbances as it is based on PI controllers. The objective of this paper is to design a new vector control that is robust to external disturbances. To achieve this, inner current loop of the conventional vector control is replaced with sliding mode control. In order to avoid chattering effect and achieve finite time convergence, the control gains are selected based on positive semi-definite barrier function. The proposed barrier function adaptive sliding mode (BFASMC) is evaluated by testing it on a benchmark multi-machine power system model under various operating conditions. The simulated results show that the proposed method is robust to various disturbances.
文摘High wind power penetration(WPP)is challenging system frequency stability.As a countermeasure,virtual inertia controls are introduced,utilizing kinetic energy(KE)stored in wind turbine generators(WTGs)for frequency regulation.Without restoration,generation efficiency of WTGs will be degraded after inertia contribution.To counter this issue,we propose an inertia control scheme of a doubly fed induction generator(DFIG),aiming at achieving dynamic inertia recovery regarding both KE and DC link energy.An asymmetrical droop control,referred to as the rate of change of frequency(RoCoF),is proposed for KE management.The upper boundary of droop gain is extended to give full play to converters and is revised,considering the system frequency state,to counter positive feedback issues induced by reversible gain regulation,which is restricted by KE to ensure stable operations as well.The inertial DC energy needed to cooperate with KE control regarding countering small fluctuations,is improved with an orderly recovery behavior.Case studies are conducted under dynamic wind conditions and the results indicate that with our proposed scheme,the ability of dynamic inertia recovery can be obtained,bringing DFIG higher generation efficiency and more adequate operation margin for sustained regulation.Essentially,the inertial frequency response and fluctuation suppression ability is well maintained.
