Current Deadbeat Predictive Control - Control of Power Inverters in Renewable Energy and Smart Grid Integration - page 258

Figure 17.1 Block diagram of a current-controlled VSI in the natural frame equipped with DB predic-
tive current controllers

According to (Buso et al. 2001; Timbus et al. 2009), the model of an inverter can be simplified
to only an inductive components as shown inFigure 17.2 for the purpose of designing a DB
controller. In this case, the grid current i can be expressed as

di ( t )
dt

R f + R g 1

=−

L g i ( t )

+ ( u i ( t ) − u g ( t )) . (17.1)

+ +

L f L f L g

With the sampling period of T s ,this can be discretised (Franklin et al. 1990; Kuo 1992;
Middleton and Goodwin 1990) as

b u i ( kT s ) u g ( kT s ) ,

i (( k + 1) T s ) = ai ( kT s ) + − (17.2)

where

R f + R g
L f + Lg T s

e − a = , (17.3)

T s 1

L f + L g T s

1 1

R f + Rg
L f + L g η d

R f + Rg

e − e − b = η = − , (17.4)

L f + L g R f + R g

0

i

R f +R g L f +L g

u i

u g

Figure 17.2 Single-phase representation for the design of DB controllers