Periodic speed ripples minimization in PM synchronous motors using repetitive learning variable structure control

Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives

“…The conventional PI speed controller is able to reduce parasitic torque and speed pulsation up to a certain extent but is not sufficient for high performance applications [38]. The VSSC is practically as simple as that of the conventional PI speed controller and can be implementable with very little additional cost that requires a measurable variable i.e.…”

Sliding-mode repetitive learning control with integral sliding-mode perturbation compensation

“…[7], the feedforward learning control was used to compensate for the error of disturbance compensation due to a disturbance observer, but this feedforward control was updated according to the tracking error of the compensated system. Previous studies [8][9][10][11] have also tried to combine the learning control with another robust feedback control, the sliding-mode control (SMC). In an SMC, the system state is directed towards some predefined switching plane and maintained there through switching control.…”

“…In Refs. [10,11], the proposed learning control contained a standard switching control. To alleviate chatter, the boundary-layer method has been adopted to smooth out the discontinuous control input in the neighborhood of a switching hyperplane [13].…”

“…Therefore, during the initial learning phase, the existence of a sliding mode and its corresponding invariance property are not assured. Furthermore, in these previous works [8][9][10][11], the feedforward components were adjusted based on either the tracking error vector or a sliding variable that is a linear combination of the error state variables.…”