基于改进型积分器的直接转矩控制的仿真研究

目前,在直接转矩控制中大多采用电压模型来估算定子磁链.然而由于纯积分环节存在直流偏移和初始值误差,会使得估算的定子磁链不准确,特别在低速时会使整个系统性能下降.采用了一种改进的积分器来消除纯积分环节产生的直流偏移和初始值误差对电压模型定子磁链观测器的影响.该积分器采用自适应控制自动调整磁链补偿量到最优值,并且通过坐标变换将幅值和相位分离,在调整幅值的同时,保持磁链的相位不发生变化,从而从本质上消除了纯积分直流偏移和初始值问题,同时还能保证定子磁链辨识无稳态误差,适合于直接转矩控制系统低速情况下使用.仿真结果验证了这种方法的有效性.

Simulation of Direct Torque Control Based on Modified Integrator

At present, the flux estimation based on voltage model is widely used in direct torque control system.However, the estimated stator flux become inaccurate because DC drift and initial value exist in the pure integrator, the system performance will be degraed, especially in the low speed area. This paper introduces a modified integrator which uses the adaptive control to adjust the flux compensation level automatically to an optimal value, separates the magnitude and angle by frame transform, and keeps the angle unchanged when adjusting the magnitude. Accordingly, the DC drift and initial value problem are essentially eliminated without adding other error to the steady state flux. This method is also more effective at low speed of direct torque control. Its feasibility is verified by the simulation results .