The estimates of unknown load torque and time-varying rotor speed converge to the corresponding true values under a persistency of excitation condition with a physically meaningful interpretation, basically equivalent to non-null synchronous frequency.
Two other methods are proposed in [53, 54, 55, 56] for DFIGs and PMSGs by adding an incremental active power based on the MPPT curve or torque limit curve to enable the rotor speed converge to a stable point when TOP ends.
The whole process is termed Stochastic Gradient Descent (SGD), although there are several variants in use that employ different methods to increase the speed of converging on a solution.
Meanwhile, f merges a decrease trend and the speed for converging to the optimum solution will continue to be accelerated gradually, which reduce the risk of falling into local convergence.
Despite its minimal structure, the closed-loop system provided adjustments that closely matched those of therapists, both in amplitude and speed to converge towards an optimal value (p > 0.05 controlled vs. manual for each rat, Ranksum test).
Second, they have slow progress in terms of fitness function in some situations (slow speed to converge to the target locations).
As shown in Fig. 9, the swimming speed almost converged to a constant value as time passed, and the average value was 0.12 m/s.
Fast converging speed and good prediction accuracy could be promised with the use of RE-Func.
The converging speed of error states can be arbitrary turned by assigning the corresponding dynamics of the sliding surfaces.
It is also found that a well approximated Jacobian matrix is essential for the IRDG method to achieve fast converging speed and maintain robustness on large-scale problems.
