1995 Volume 115 Issue 10 Pages 1205-1214
Novel design theory for a three phase self commutated power conversion system (PCS) to perform as a 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 which comes in constant period. The performance is theoretically evaluated. Simulation by SPICE is also executed and the characteristics are inspected.
Error tracking mode has following attractive features. It can treat arbitrary two current waveforms as target functions of arbitrary two phase 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 get 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 surely makes contributions to improve precision in current control and to reduce current harmonics of self commutated voltage source power converters.