Papers about this topic include simulation models, circulating current reduction, voltage modulators, capacitor voltage balancing and control issues.
More intensive theoretical and practical studies should be investigated to determine how to coordinate the interior power control, modulation method, circulating current suppression, and voltage balancing with exterior voltage and current compensation requirements.
The inhibition effect of harmonic circulating current by instantaneous voltage feedback method is verified in five frequencies.
The main characteristics are: 4-quadrant AC/DC converter 12-pulse with circulating current, DC load voltage ±1000 V and DC load current ±5 kA.
Open image in new window Fig. 6 Flow diagram for calculating optimal branch voltages for circulating current optimization control.
Second, an examination of the effect of changing the arm inductor for MMC behavior is carried out based on many simulation results in this paper in order to analyze the change in THD for all MMC quantities, including circulating current, upper arm current and voltage, lower arm current and voltage, and AC output voltage and current.
Also, it presents the effects on MMC quantities, such as a circulating current ripple, maximum output voltage, and submodule capacitor ripple responses with increasing the value of arm inductance.
The proposed tuning-less MPC is capable of direct active and reactive power control, circulating current minimization, submodule capacitor voltage balancing, switching frequency reduction, and great resilience under balanced and unbalanced grid conditions.
Meanwhile, the capability of capacitor voltage balancing control and circulating current control in the proposed PDPC is as good as in the predictive current controllers.
This paper proposes a novel voltage predictive based MPC strategy, which combines the ac-side current and circulating current control by using forward differential voltage prediction and nearest level approximation.
