Performance Evaluation of a Time-Optimal Current Controller for a Voltage-Source Converter and Comparison With a Hysteresis Controller

This paper proposes a time-optimal current-control (TOCC) algorithm for a space vector modulation-based voltage-source converter. The term “time optimal” refers to optimally controlled reference current tracking in order to gain the shortest durations of current transients. The dynamics of the proposed controller are compared with a nonlinear hysteresis controller known for its good dynamic performance. For the two algorithms, the response to a reference step change is observed using PSCAD simulations. Results show that despite its digital implementation and constant switching frequency, the TOCC algorithm in most cases provides faster transient responses than the hysteresis controller. The operation of the TOCC algorithm was during balanced and unbalanced voltage sags evaluated as stable and very fast.