Model predictive control of interleaved boost converters for synchronous generator wind energy conversion systems

Interleaved boost converters are used in multimegawatt wind energy conversion systems with synchronous generators (SG), after a diode rectifier stage to control the generator and provide voltage elevation for the grid connection at lower speeds. The use of a diode rectifier is possible due to the fact SG do not consume reactive power, making it a cost-effective solution to reduce the size and cost of the full-scale converter needed in SG based turbines. This paper proposes a finite control set model predictive control (FCS-MPC) for the interleaved boost converter capable of effectively distributing the power among the different boost channels. In addition, a new strategy to fix the switching frequency is introduced to the predictive control algorithm. A criterion is presented for the design of the weighting factors. The control method has been tested through simulation on a three-channel interleaved boost converter. The steady-state behavior achieved with the proposed method is similar to the one obtained with classic PI control and PWM. This work enables the use of FCS-MPC for interleaved boost converters, to be further included in existing FCS-MPC algorithms for applications where these converters are used, such as SG based wind energy conversion systems, where this control strategy has already been used for the grid side converter.