This paper presents a multiple target implementation technique for a doubly fed induction generator （DFIG） under unbalanced and distorted grid voltage based on direct power control （DPC）. Based on the mathematical...This paper presents a multiple target implementation technique for a doubly fed induction generator （DFIG） under unbalanced and distorted grid voltage based on direct power control （DPC）. Based on the mathematical model of DFIG under unbalanced and distorted voltage, the proportional and integral （PI） regulator is adopted to regulate the DFIG average active and reactive powers, while the vector P1 （VPI） resonant regulator is used to achieve three alternative control targets： （1） balanced and sinusoidal stator current; （2） smooth instantaneous stator active and reactive powers; （3） smooth electromagnetic torque and instantaneous stator reactive power. The major advantage of the proposed control strategy over the conventional method is that neither negative and harmonic sequence decomposition of grid voltage nor complicated control reference calculation is required. The insensitivity of the proposed control strategy to DFIG parameter deviation is analyzed. Finally, the DFIG experimental system is developed to validate the availability of the proposed DPC strategy under unbalanced and distorted grid voltage,展开更多
We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional reso...We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional resonant part and vector proportional integral(VPI) regulator with VPI resonant part. Based on the mathematical model of DFIG under distorted grid voltage, the transfer function and frequency response characteristics of the two current regulators are analyzed and compared. The superiority of the VPI current regulator over the PIR regulator is pointed out, and the influence of discretization methods on the performance of the resonant current regulator is studied. All the results are validated by MATLAB simulation and experiments.展开更多
The medial entorhinal cortex of rodents is known to contain grid cells that exhibit precise periodic firing patterns based on the animal’s position,resulting in a distinct hexagonal pattern in space.These cells have ...The medial entorhinal cortex of rodents is known to contain grid cells that exhibit precise periodic firing patterns based on the animal’s position,resulting in a distinct hexagonal pattern in space.These cells have been extensively studied due to their potential to unveil the navigational computations that occur within the mammalian brain and interesting phenomena such as so-called grid cell distortions have been observed.Previous neuronal models of grid cells assumed their firing fields were independent of environmental boundaries.However,more recent research has revealed that the grid pattern is,in fact,dependent on the environment’s boundaries.When rodents are placed in nonsquare cages,the hexagonal pattern tends to become disrupted and adopts different shapes.We believe that these grid cell distortions can provide insights into the underlying neural circuitry involved in grid cell firing.To this end,a calibration circuit for grid cells is proposed.Our simulations demonstrate that this circuit is capable of reproducing grid distortions observed in several previous studies.Our model also reproduces distortions in place cells and incorporates experimentally observed distortions of speed cells,which present further opportunities for exploration.It generates several experimentally testable predictions,including an alternative behavioral description of boundary vector cells that predicts behaviors in nonsquare environments different from the current model of boundary vector cells.In summary,our study proposes a calibration circuit that reproduces observed grid distortions and generates experimentally testable predictions,aiming to provide insights into the neural mechanisms governing spatial computations in mammals.展开更多
A doubly-fed induction generator(DFIG)based configuration is still preferred by wind turbine manufacturers due to the cost-effective power converter and independent control of the active power and reactive power.To co...A doubly-fed induction generator(DFIG)based configuration is still preferred by wind turbine manufacturers due to the cost-effective power converter and independent control of the active power and reactive power.To cope with stricter grid codes(e.g.reactive power compensation,low voltage ride-through operation,as well as steady and safe operation during long-term distorted grid),control strategies are continuously evolving.This paper starts with a control strategy using the combined reactive power compensation from both the back-to-back power converters for their optimized lifetime distribution under normal grid conditions.Afterwards,an advanced demagnetizing control is proposed to keep the minimum thermal stress of the rotor-side converter in the case of the short-term grid fault.A modularized control strategy of the DFIG system under unbalanced and distorted grid voltage is discussed,with the control targets of the smooth active and reactive power or the balanced and sinusoidal current of the rotor-side converter and the grid-side converte。Finally,a bandwidth based repetitive controller is evaluated to improve the DFIG system's robustness against grid frequency deviation.展开更多
基金Project supported by the National High-Tech R&D Program(863)of China(No.2011AA050204)the National Natural Science Foundation of China(No.51277159)
文摘This paper presents a multiple target implementation technique for a doubly fed induction generator （DFIG） under unbalanced and distorted grid voltage based on direct power control （DPC）. Based on the mathematical model of DFIG under unbalanced and distorted voltage, the proportional and integral （PI） regulator is adopted to regulate the DFIG average active and reactive powers, while the vector P1 （VPI） resonant regulator is used to achieve three alternative control targets： （1） balanced and sinusoidal stator current; （2） smooth instantaneous stator active and reactive powers; （3） smooth electromagnetic torque and instantaneous stator reactive power. The major advantage of the proposed control strategy over the conventional method is that neither negative and harmonic sequence decomposition of grid voltage nor complicated control reference calculation is required. The insensitivity of the proposed control strategy to DFIG parameter deviation is analyzed. Finally, the DFIG experimental system is developed to validate the availability of the proposed DPC strategy under unbalanced and distorted grid voltage,
基金Project supported by the National High-Tech R&D Program(863)of China(No.2011AA050204)the National Natural Science Foundation of China(No.51277159)
文摘We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional resonant part and vector proportional integral(VPI) regulator with VPI resonant part. Based on the mathematical model of DFIG under distorted grid voltage, the transfer function and frequency response characteristics of the two current regulators are analyzed and compared. The superiority of the VPI current regulator over the PIR regulator is pointed out, and the influence of discretization methods on the performance of the resonant current regulator is studied. All the results are validated by MATLAB simulation and experiments.
基金the European Union’s Horizon 2020 Framework Program for Research and Innovation under Specific Grant Agreement(SGA)Number 945539(Human Brain Project SGA3).
文摘The medial entorhinal cortex of rodents is known to contain grid cells that exhibit precise periodic firing patterns based on the animal’s position,resulting in a distinct hexagonal pattern in space.These cells have been extensively studied due to their potential to unveil the navigational computations that occur within the mammalian brain and interesting phenomena such as so-called grid cell distortions have been observed.Previous neuronal models of grid cells assumed their firing fields were independent of environmental boundaries.However,more recent research has revealed that the grid pattern is,in fact,dependent on the environment’s boundaries.When rodents are placed in nonsquare cages,the hexagonal pattern tends to become disrupted and adopts different shapes.We believe that these grid cell distortions can provide insights into the underlying neural circuitry involved in grid cell firing.To this end,a calibration circuit for grid cells is proposed.Our simulations demonstrate that this circuit is capable of reproducing grid distortions observed in several previous studies.Our model also reproduces distortions in place cells and incorporates experimentally observed distortions of speed cells,which present further opportunities for exploration.It generates several experimentally testable predictions,including an alternative behavioral description of boundary vector cells that predicts behaviors in nonsquare environments different from the current model of boundary vector cells.In summary,our study proposes a calibration circuit that reproduces observed grid distortions and generates experimentally testable predictions,aiming to provide insights into the neural mechanisms governing spatial computations in mammals.
文摘A doubly-fed induction generator(DFIG)based configuration is still preferred by wind turbine manufacturers due to the cost-effective power converter and independent control of the active power and reactive power.To cope with stricter grid codes(e.g.reactive power compensation,low voltage ride-through operation,as well as steady and safe operation during long-term distorted grid),control strategies are continuously evolving.This paper starts with a control strategy using the combined reactive power compensation from both the back-to-back power converters for their optimized lifetime distribution under normal grid conditions.Afterwards,an advanced demagnetizing control is proposed to keep the minimum thermal stress of the rotor-side converter in the case of the short-term grid fault.A modularized control strategy of the DFIG system under unbalanced and distorted grid voltage is discussed,with the control targets of the smooth active and reactive power or the balanced and sinusoidal current of the rotor-side converter and the grid-side converte。Finally,a bandwidth based repetitive controller is evaluated to improve the DFIG system's robustness against grid frequency deviation.
