Decoupled stationary ABC frame current control of three-phase four-leg four-wire converters

Abstract

This paper analyzed a method for decoupling the current control loop of three-phase converters in the stationary abc frame, which is valid for both the three-leg three-wire and four-leg four-wire (with neutral inductor) topologies. As control in the abc frame presents an extra degree of freedom for the converter references, the extra reference is set to zero or the negative sum of the others. The latter decoupled the closed-loop system, assuming that there were no voltage disturbances. The two options were compared through a transfer matrix analysis, simulations and experimental results. With the suggested control structure, a simple and effective control implementation can be achieved in the abc frame.