无刷双馈电机滑模变结构直接转矩控制

针对无刷双馈电机直接转矩控制系统磁链和转矩脉动大的问题,引入滑模变结构控制策略.以转矩和磁链两个滑模控制器来代替传统直接转矩控制中的两个滞环控制器,电压矢量开关的输出采用空间电压矢量PWM调制的方法,保证了逆变器开关频率恒定,应用指数趋近率方法设计滑模控制器,由Lyapunov方法求得相应的滑模变结构控制律,建立了MATLAB/Simulink环境下直接转矩控制系统的仿真模型,仿真结果表明,新型控制方案能有效减小转矩脉动,改善定子磁链和电流波形,同时仍可保持直接转矩控制固有的转矩快速响应的优点,提高系统的稳定性和鲁棒性.

Direct-torque control of the brushless double-fed machines based on sliding-mode variable structure control strategy

A novel sliding-mode variable structure(SMVS) control strategy is proposed to reduce the ripples of flux and torque of brushless double-fed machines(BDFM) based on direct torque control system(DTC). In order to ensure the constant switching frequency for the inverter, two hysteresis regulators in the conventional DTC system are substituted by the SMVS controllers of flux and torque, and the space voltage vector pulse-width-modulation is used in the output of the voltage vector switches. The SMVS controllers are designed with the method of exponential approach law, and the Lyapunov stability theory is utilized to solve for the control law of the SMVS controllers. The simulation model of DTC is established in MATLAB/Simulink environment. The simulation results show that this new control method effectively reduces the torque ipples and improves the waveforms of the stator flux and current. The inherent advantage of the fast dynamic-response of the torque in DTC is reserved. The stability and robust performance of the system is enhanced.