Grid friendly digital control of active front-end converters

The active front-end converter (AFC) can provide constant/controllable DC-bus voltage, nearly sinusoidal input current, controllable power factor, and regenerating capability. Hence, the AFC has been so far very attractive and investigated extensively. In this text, a research work for an AFC on the basis of two-level VSC is introduced. The investigation was emphasized on a control strategy of AFC and a possibility to combine or to extend its functionality to work in parallel in different working modes or in different applications. As a result, a grid-friendly control strategy for the AFC extended functionally with shunt active filter was proposed. In order to achieve a complete digitalizing in control and a high dynamic performance, a deadbeat control technique has been adopted to develop an inner current controller. A deadbeat response with high dynamic as well as an improved performance can be achieved with the help of a proper control compensation and adaptive parameter control. The proposed control scheme was implemented and verified with a commercial AFC platform of Bosch Rexroth AG and set-up in a training experiment system of distributed drive system.