Current Deadbeat Predictive Control
As shown in the previous two chapters, PI controllers in the dq frame and PR controllers in the αβ or abc frame can be adopted to track the reference set for the grid current so that the power exchanged with the grid is regulated. They are able to track pure sinusoidal reference currents without steady-state errors under balanced conditions. In this chapter, a deadbeat (DB) predictive controller is discussed so that the grid currents can track the grid current references within two sampling steps so that the dynamic performance is improved. The controller is designed and implemented in the natural (abc) reference frame.
17.1 Control Structure
The block diagram of a current-controlled VSI in the natural (abc) frame with the DB predictive controller is shown in Figure 17.1. Each phase current is independently controlled via a DB predictive controller, which takes the reference current, the grid current and the grid voltage as inputs. The three-phase current references are generated from the dq current references Id* and Iq* with a transformation.
17.2 Controller Design
The basic idea of a DB controller is for the controlled ...