High-power-factor single-phase capacitor clamped rectifier

A control scheme for a single-phase capacitor clamped rectifier is proposed. Flying capacitor configuration has been employed as a power factor correction to achieve a high-input power factor and low-current harmonics. The adopted rectifier allows higher voltage than the voltage stress of the power switches to be achieved. The control scheme, based on a look-up table with hysteresis current controller (HCC), can (i) draw a nearly sinusoidal line current, (ii) achieve a unity power factor, (iii) reduce the current harmonics, and (iv) improve the unbalance problem between capacitor voltages. The applications of the adopted converter can be also used in multilevel active power filters, uninterruptible power supplies and high-power motor drives. The experimental results are shown to confirm the validity of the proposed concept.