Performance evaluation of an improved model predictive control with field oriented control as a benchmark

Abstract

Compared to the widespread modulation-based control strategies such as field oriented control (FOC), MPC eliminates the use of internal current control loops and modulation block, hence featuring very quick dynamic response. Furthermore, MPC well respects the discrete nature of power converters by evaluating the influence of each voltage vector on the concerned control variables, which are usually combined into a cost function, hence featuring simple concept. In spite of the merits of quick response and conceptual simplicity, it seems that MPC may be inferior to FOC in terms of steady-state performance, especially in the low speed range, which is usually a drawback of MPC-branched methods. This study proposes an improved two-vectors-based MPC (MPC2) and compares it to the well-established FOC. A detailed experimental study of both methods is presented, including steady-state performance, dynamic response, low speed operation and control complexity. Very promising results are obtained in MPC2 by providing better steady-state performance and much quicker response than FOC under the condition of similar average switching frequency. The results prove that MPC2 is a powerful alternative to FOC and may find wide applications in the near future.