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A robust current control approach with disturbance cross-coupling compensation for permanent magnet synchronous motor drives (PMSM) is proposed in this paper. The proposed approach can enhance the reference tracking and provides a robust option for current control of PMSM drives. A discrete-time sliding mode current controller is proposed. The PMSM model includes the digital implementation delay, present due to the discrete-time algorithm execution. A discrete-time backstepping disturbance observer is developed, being combined to the sliding mode controller as a means to improve the robustness and tracking capability. The effects of coupling, parametric uncertainties and load disturbances are compensated by the backstepping disturbance observer. The stability analysis of the combined system is presented and the limits for overall system stability are discussed. Simulations and experimental results validate the combined scheme and demonstrate the good performance of the proposal. • The proposal includes the digital implementation delay in the problem formulation. • The proposed system is analyzed in the discrete-time domain. • Mitigation of the coupling effect in dq axes via the disturbance observer. • The proposed switching functions cross the sliding surface at each sampling period. • A simple structure suitable to nonlinear plants with mismatched uncertainties [ABSTRACT FROM AUTHOR]

This article proposes an alternative for robust control of synchronous reluctance motors using linear matrix inequalities to obtain fixed gains that ensure current and speed regulation, under parameter uncertainties and variations. The proposed design procedure is based on a polytopic model, which takes into account: i) uncertainties and variations of the mechanical and electrical parameters of the motor, ii) one step delay from digital implementation of the control law, and iii) internal model based controllers to guarantee reference tracking. Less conservative linear matrix inequalities, relying on slack variables, ensure robust pole location and certify the closed-loop stability for the entire domain of uncertain and time-varying motor parameters, based on parameter-dependent Lyapunov functions. The linear matrix inequalities ensure a fast and systematic computation of the control gains, that are also easy to be implemented, not adding computational complexity when compared, for instance, to usual strategies based on PI controllers. Experimental results for a 2.2 kW commercial motor are provided, validating the proposed procedure, and illustrating good tracking of currents and speed references, with suitable dynamic responses and reduced cross-coupling effects, when compared to sliding mode and PI controllers. [ABSTRACT FROM AUTHOR]