A grid voltage perturbations based bidirectional impedance uniform control for grid‐connected DC/AC converter

Abstract

For bidirectional grid‐connected DC/AC converters, the power flow variation substantially alters the system stability, and especially severs under heavy load. Towards this problem, this paper proposes a novel impedance uniform control method to eliminate the stability degradation under power flow variations, which is achieved by reshaping the converter negative incremental impedance to resistive in the stability fragile mode. The d‐axis voltage perturbation is extracted to dynamically modify the active power current reference. Hence, the system bidirectional damping performance can be simultaneously improved by this dedicated design. Without switching control modes or sacrificing dynamic performance, the grid‐connected converter system can maintain satisfied stability under bidirectional power flow variations. Finally, the effectiveness of the proposed control method has been validated by both simulations and experiments.

ANFIS-based FOPID controller to enhanced stability of cascaded converter for electric vehicle (EV) charger

“…From figure 2, the open loop and close loop output impedance of VSC are mentioned in (1) and (2) and more details of derivation are found in [13].…”

“…Traditionally, the regulation of the voltage of the converter has been accomplished by using a PI controller due to its ease of implementation. However, its limitations include difficulties in tuning for non-linear systems and sensitivity to parameter variation [13]. PID controllers find widespread application in various industries for enhancing both the transient and steady-state performance of the system.…”