Dynamic properties of a step-down sinusoidal current AC/DC converter under state-feedback control

A control system is presented for a switching AC/DC converter which complies with electromagnetic compatibility (EMC) standards on conducted emissions and is suitable for applications presently using line-commutated controlled-rectifiers. The properties of the buck converter (which steps-down from 0.866 V_line(peak)) are compared to those of the established boost converter (which steps-up from V_line(peak)). The reduction in size of the energy storage components compared with those of a line-commutated controlled-rectifier is examined. A control strategy able to provide a well-regulated output while exploiting the fast response of the power circuit is designed. A state-feedback controller is implemented using programmable logic and an embedded microcontroller. A 3 kVa insulated gate/bipolar transistor (IGBT) converter is used to demonstrate low input-current distortion, controllable displacement-factor, load current disturbance rejection and fast-response output voltage changes