Transformer Less Power Transfer at Unity Power Factor via HVDC Link Using Improved Power Quality HCC PWM AC-DC Converter

The three-phase bridge topology of the bi-directional boost type improved power quality ac-dc converter (IPQC) is capable of providing power transfer between a high voltage dc (HVDC) link and a relatively low voltage ac system with improved power quality at input ac mains in terms of high power factor and low THD. This paper presents unity power factor operations, in the rectification and inversion modes, with near sinusoidal line currents; of the IPQC that employs IGBTs. The current forced control (CFC) strategy is implemented with closed loop control, adopting the hysteresis-band current control (HCC) pulse width modulation (PWM) technique. Simulation results confirm the efficacy of the control technique.