AC filter voltage reconstruction in PWM-CSR

Three-phase Pulse Width Modulated rectifiers are successfully used in industrial applications. They feature fast dynamic response, a constant dc current or voltage control loop, low both ac and dc harmonic distortion, bi-directional power flow, and unity power factor control. The development of control methods for this type of rectifiers has been possible thanks to the advances in power semiconductor devices, which have diminished their cost and increased their speed of operation allowing the implementation of very sophisticated control algorithms. On the other hand, the application of control strategies based on non-linear techniques has demonstrated excellent results in control process applications and electric power systems because these methods consider the internals non-linearities, coupled behavior, and other existing phenomena in most of real systems. Unfortunately, these have not been amassed at industrial level due mainly to the large amount of variables that are necessary to measure. This work proposes a voltage reconstruction technique applied to the ac filter of a PWM-CSR. Experimental results obtained from a 2 kVA DSP TMS320C30 based prototype are shown to confirm the validity of the theoretical considerations.