从并网风力发电系统的发展趋势出发,对现代风力发电机组进行了比较.分析了双馈感应电机数学模型及其定子磁链定向矢量控制模型,论证了其无功功率和转矩的独立控制的可行性,探讨了转子电流解藕控制的控制方案并给出了PID闭环控制方案.在...从并网风力发电系统的发展趋势出发,对现代风力发电机组进行了比较.分析了双馈感应电机数学模型及其定子磁链定向矢量控制模型,论证了其无功功率和转矩的独立控制的可行性,探讨了转子电流解藕控制的控制方案并给出了PID闭环控制方案.在数学模型的基础上搭建了MATLAB/SIMULINK仿真模型对结论进行了验证.The study of the vector control system of the展开更多
The unbalanced voltages cause negative effects on the doubly fed induction generator （DFIG） sucn as torque pulsation,and increased stator current. Based on the symmetrical component theory, the torque pulsation is t...The unbalanced voltages cause negative effects on the doubly fed induction generator （DFIG） sucn as torque pulsation,and increased stator current. Based on the symmetrical component theory, the torque pulsation is the consequence of the interaction of stator and rotor currents of different sequences. This paper presents a control technique to reduce the effect of unbalanced voltages on the DFIG in wind energy conversion systems. The negative sequence stator voltage is derived from the unbalanced three phase stator voltages. The compensated rotor voltage in terms of the derived negative sequence stator voltage and slip which minimizes the negative stator and rotor currents is proposed. The results from the simulation of control system with steady state model and dynamic model of the DFIG show that additional control loop with compensated voltage can significantly reduce torque and reactive power pulsations.展开更多
VFT （variable frequency transformer） has been recently used as art alternative to HVDC （high voltage direct current） to control power flow between asynchronous networks. VFT consumes less reactive power than a bac...VFT （variable frequency transformer） has been recently used as art alternative to HVDC （high voltage direct current） to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIM （doubly-fed induction machine） where the machine torque controls the power flow from stator to rotor and vice versa. The main disadvantage of this VFT is the slip rings and brushes required for the rotor circuit, especially in bulk power transmission. The BDFM （brushless doubly-fed machine） with nested cage rotor machine is proved to be a comparable alternative to conventional DFIM in many applications with the advantage that all windings being in the stator frame with fixed output terminals. In this paper, the BDFM is used as a BVFT （brushless variable frequency transformer）. A prototype machine is designed and simulated to verify the system validity.展开更多
文摘从并网风力发电系统的发展趋势出发,对现代风力发电机组进行了比较.分析了双馈感应电机数学模型及其定子磁链定向矢量控制模型,论证了其无功功率和转矩的独立控制的可行性,探讨了转子电流解藕控制的控制方案并给出了PID闭环控制方案.在数学模型的基础上搭建了MATLAB/SIMULINK仿真模型对结论进行了验证.The study of the vector control system of the
文摘The unbalanced voltages cause negative effects on the doubly fed induction generator （DFIG） sucn as torque pulsation,and increased stator current. Based on the symmetrical component theory, the torque pulsation is the consequence of the interaction of stator and rotor currents of different sequences. This paper presents a control technique to reduce the effect of unbalanced voltages on the DFIG in wind energy conversion systems. The negative sequence stator voltage is derived from the unbalanced three phase stator voltages. The compensated rotor voltage in terms of the derived negative sequence stator voltage and slip which minimizes the negative stator and rotor currents is proposed. The results from the simulation of control system with steady state model and dynamic model of the DFIG show that additional control loop with compensated voltage can significantly reduce torque and reactive power pulsations.
文摘VFT （variable frequency transformer） has been recently used as art alternative to HVDC （high voltage direct current） to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIM （doubly-fed induction machine） where the machine torque controls the power flow from stator to rotor and vice versa. The main disadvantage of this VFT is the slip rings and brushes required for the rotor circuit, especially in bulk power transmission. The BDFM （brushless doubly-fed machine） with nested cage rotor machine is proved to be a comparable alternative to conventional DFIM in many applications with the advantage that all windings being in the stator frame with fixed output terminals. In this paper, the BDFM is used as a BVFT （brushless variable frequency transformer）. A prototype machine is designed and simulated to verify the system validity.
