Predictive Control of Three Phase AC/DC Converters

Chapter 5
Investigations of Control
Methods Performance
5.1 Robustness to Parameters Mismatch
Model Predictive Control bases on mathematical description of the grid and converter.
Algorithm works correct as long as the parameters used in model are
correct. In this Chapter influence of model parameters mismatch: choke inductance
L and resistance R, will be investigated for VSF and CSF control methods.
Furthermore, on-line choke inductance estimator will be presented. Also, selected
control methods will be tested under line voltage distortions. Investigations have
been performed on the basis of simulation models and experimental tests on
laboratory set-up as well.
5.1.1 Filter‘s Inductance Variations
Figure 5.1 shows average switching frequency F swAV in VSF-P-DPC method for
1 and 2 kW of load versus choke inductance value mismatch, used in predictive
model L C . Choke inductance mismatch ∆L is defined as:
∆L = L C − L
100[%] (5.1)
L
where L C is inductance used in control method, and L is real value. Figure 5.2
shows calculated power error ∆S defined as:
∆S =
√
(Pref − P ) 2 + (Q ref − Q) 2
√
P 2 ref + Q2 ref
(5.2)
versus ∆L whereas, Fig. 5.3 shows T HD i factor variation under L mismatch.
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