Deadbeat Control for Electrical Drives: A Robust and Performant Design Based on Differential Flatness

The present contribution introduces a new deadbeat controller design that increases robustness without compromising performance. In conventional deadbeat control, feedback linearization is applied, and the feedback gains are set very high to obtain the minimum-step reference response. This makes the control method highly sensitive to parametric uncertainties. To date, the only remedies have been to tune the deadbeat controller settling time higher and the according disturbance estimator more slowly. Recently proposed remedies based on online parameter estimators show either moderate performance or higher demands on hardware. Therefore, first a feedforward linearization-based controller is introduced to obtain the desired reference response via open-loop control. Thereby, the parametric sensitivity is considerably improved. Then, the new generalized flatness-based controller, a mix between feedback and feedforward linearization, is proposed. The result is a deadbeat controller with high dynamic performance and high robustness with respect to both parameter uncertainties and disturbances. The experimental results on an induction machine demonstrate very fast reference tracking, high robustness to typical parameter uncertainties, and active compensation of time-varying disturbances. The results on a synchronous reluctance machine show that even very large inductance uncertainties can be handled.