Deadbeat Flux Vector Control for Dynamic Six-Step Operation of Synchronous Machines

Abstract

This paper proposes a deadbeat flux vector regulator to control flux along a hexagonal flux trajectory for six-step operation. Since the stator flux is directly controlled at every sampling instant, fast and smooth flux and torque generation is achieved both in steady state and transient operations. A key feature of this control technique is that deviations from the ideal six-step flux trajectory can be detected and corrected at every sample instant resulting in a very fast transient response and good disturbance rejection properties while maintaining six-step operation. Furthermore, this approach allows transitioning in and out of six-step within a few sampling periods. By using flux as the primary control variable, the control law is simple to implement and only relies on a few parameters. Moreover, this paper analyzes discrete time control limitations and stator resistance sensitivity and proposes techniques to mitigate these limitations. The paper presents simulation-based and experimental evaluation of the control approach and compares it to conventional six-step voltage angle torque control.