Error tracking mode AC current waveform control method for three‐phase self‐commutated voltage source power converters

Abstract

AbstractA novel design theory for a three‐phase self‐commutated power conversion system (PCS) to perform as an ac current source is proposed. In this new ac current waveform control method termed error tracking mode, the switching instructions of main devices are decided only by the error function of ac current at every data sampling time that comes in a constant period. The performance is theoretically evaluated. Simulation by SPICE also is executed and the characteristics are inspected.Error tracking mode has the following attractive features. It can treat two arbitrary current waveforms as target functions of two‐phase arbitrary ac currents. The error between actual ac current value and the objective function value can be controlled and guaranteed to be less than an arbitrary value, which is given beforehand. All control components can be digitized. The minimum continuous on and off time of main devices is guaranteed in advance. No special starting control is necessary because actual ac currents are guaranteed to start tracking the target functions automatically. Error tracking mode makes contributions to improve precision in current control and to reduce current harmonics of self‐commutated voltage source power converters.