One of the main problems of multivariable cost functions in model
predictive control is the choice of weighting factors. Two finite
control set model predictive control algorithms, applied to the
three-phase active rectifier with an LCL filter, are described in the
paper. The investigated algorithms, i.e. PCi_{c}u_{c}
and PCi_{g}i_{c}u_{c}, implement multivariable
approaches applying line (grid) current, capacitor voltage and converter
current. The main problem dealt with in the paper is the choice of
optimum values of the cost function weighting factors. The values of the
factors calculated using the method proposed in the paper are very close
to the values represented by the lowest THDi of the line current.
Moreover, simulations verifying the equations used in the prediction of
controlled values, i.e. line current, capacitor voltage and converter
current, are presented. Both simulation and experimental results are
presented to verify effectiveness of the investigated control strategies
under change of the load (P = 5 kW and 2.5 kW), during transient states,
under unbalanced and balanced line voltage.