Cascaded Continuous and Finite Model Predictive Speed Control for Electrical Drives

This paper presents a new cascaded model predictive control (MPC) approach for electrical drives. The new cascaded continuous and finite model predictive control (CCF-MPC) combines two different predictive control algorithms in a cascaded structure. The finite control set approach (FCS-MPC) offers an optimised current control and the continuous control set approach (CCS-MPC) enables an optimal speed control. The cascaded control scheme allows a prediction in dependence on electrical and mechanical time constants. The separation of the time constants offers an optimum between the discrete granularity of the predictive step size and the possible length of the prediction horizon. In this way, a predictive control of the entire mechatronic system is possible. In addition, non-linear and linear equations of the drive system are separated. The results of the proposed method show an optimised current with highly dynamic behaviour in combination with an active damping of oscillations at the mechanical shaft of the drive system, which are beneficial for mechatronic applications.