Control of Power Inverters in Renewable Energy and Smart Grid Integration电力—ch17.pdfVIP

17 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 I ∗ d and I ∗ with a dq → abc transformation. q 17.2 Controller Design The basic idea of a DB controller is for the controlled variable to reach its desired value within fixed periods of sampling. In inverter control, this is widely employed, with the capability of predicting the reference current and the grid voltage, to track sinusoidal currents (Buso et al. 2001; Habetler 1993; Holmes and Martin 1996; Kawabata et al. 1990, 1991; Kojabadi et al. 2006; Lindgren 1996; Lindgren and Svensson 1998; Mohamed and El-Saadany 2007, 2008b; Wu and Lehn 2006; Zeng and Chang 2008). A DB predictive controller is able to provide a fast dynamic response but it is sensitive to system uncertainties (Timbus et al. 2009; Zeng and Chang 2005). Control of Power Inverters in Renewable Energy and Smart