Robust Control of High-Speed Synchronous Reluctance Machines

High-speed regimes allow an increase in the power density of electrical drives, which is a necessary characteristic in aeronautical applications. In such a context, together with the typical nonlinearities of low-speed drives, i.e., core saturation, phenomena related to high fundamental to sampling frequency ratios appear increasingly significant. This paper applies methodologies based on modern robust control to high-speed synchronous reluctance machines. The proposed method is based on a reformulation of the motor model as a linear parameter varying system. This allows transforming the current controller design in a multivariable optimization problem, which is solved with efficient numeric tools. The mathematical formulation of a robust digital controller directly designed in the discrete time domain is proposed. The controller performance are experimentally compared to of its counterpart designed in the continuous-time domain, and subsequently, discretized, as proposed in a previous work by the same authors, to have agreement a more standard decoupled current control using proportional-integral regulators. Results demonstrate the effectiveness of the proposed controller structure in current regulation, especially at high-speed regimes.