A Frequency Adaptive Repetitive Control for Active Power Filter With 380V/75A SiC-Inverter

Analysis and stabilization for full harmonic compensation oscillation in SAPF system with source current direct control

“…Let Δ = 0, in order to clarify the contribution of each transfer function to the system loop gain, the positive sequence loop gain T p (s) can be transformed as (17). According to Nyquist stability criterion, once the curve of the loop gain T(s) (T(s) = T p (s) + T n (s)) wraps around (−1, j0), it implies the righthalf plane (RHP) poles for the closed-loop system which leads to instability.…”

“…In the above discussion, the loop gain of the system T(s) has been derived with the positive sequence component as in (15)and (17). Since the positive and negative sequences around harmonic frequencies are almost identical, it is possible to start with the analysis of the positive sequence component T p (s).…”

“…Since the Bode plots of T p (s) and T n (s) have similar characteristics, the analysis can be developed based on T p (s). Observing (17) it can be concluded that T p (s) includes three parts: the active link of CIC, the interaction of the source impedance with the non-linear load and with the SAPF. Besides, it is obvious |L f s| < < |1+G i (s)| so that the effect of Y i (s) is insignificant and T p (s) can be further simplified into the passive and the active part as: (18) Figure 12 shows the separated Bode plots of T pP (s) and T pA (s).…”

“…To fully exploit the advantages of SAPF in novel power distribution systems, many scholars pursue advanced control strategies (e.g. sliding-mode control [12][13][14], repetitive control [15][16][17], predictive control [18][19][20], H∞ control [21] etc.). Meanwhile, the optimization of SAPF in multi-node systems to achieve global configuration of power quality is also a popular topic [22][23][24].…”

Constant Delay-Line Repetitive Control Analysis for Variable Frequency Operation

“…Moreover, the 2 oversampling reduces the available time that can be used to perform the calculations related to the control algorithm. In [16] the effects of having a variable output fundamental frequency have been compensated thanks to the usage of a very high switching frequency SiC inverter. However, that approach is very limited to a certain device and for medium to low power applications.…”