A predictive current control scheme with reduction of the switching frequency for a NPC inverter was presented in Chapter 5. In this scheme, the cost function presents a primary term for current reference tracking and a secondary term for reduction of the switching frequency:
The secondary term corresponds to the predicted number of switchings involved when changing from the present to the future switching state. Thus by increasing the associated weighting factor λsw it is expected that this term gains more importance in the cost function and forces a reduction in the switching frequency, an effect that can be clearly seen in Figure 11.2a. This figure has been obtained by performing several simulations, starting with λsw = 0 and gradually increasing this value after each simulation.
It can be observed in these results that a reduction in the switching frequency introduces higher distortion, affecting ...