Inductor Saturation Compensation in Three-Phase Three-Wire
Voltage-Source Converters via Inverse System Dynamics-II
Abstract
Current waveform quality and current control bandwidth are the figures
of merit for current controllers in three-phase three-wire (3P3W)
voltage-source converter (VSC) systems. When saturable inductors are
employed as converter side inductors due to cost, size, and energy
conversion efficiency benefits in 3P3W VSCs with conventional
synchronous frame current control (CSCC); substantial drawbacks arise by
means of these figures of merit. In the preceding part of this study, an
inverse dynamic model based compensation (IDMBC) method has been
proposed to deal with these drawbacks. Complementarily, this paper
presents a thorough analytical investigation of the control system
characteristics of CSCC and IDMBC methods that affect the current
waveform quality and current control bandwidth. The analyses are
verified via dynamic response and waveform quality simulations and
experiments that employ saturable inductors reaching $1/9^{th}$
of the zero-current inductance at full current. The results obtained
demonstrate the suitability of the IDMBC method for 3P3W VSCs employing
saturable inductors.