Iterative learning control for variable frequency drives

Variable frequency drives (VFD) are subject to various types of disturbances especially cyclical ones. These periodic disturbances are difficult to compensate by conventional controllers. Repetitive control can only compensate for constant frequency fluctuations. PWM inverter based VFDs are subject to periodic disturbances with variable frequency. In this paper, a new angle domain based iterative learning controller (ILC) is proposed to compensate for the variable frequency disturbances.