Continuous-Control-Set Model Predictive Control with Integrated Modulator in Permanent Magnet Synchronous Motor Applications

Abstract

A key aspect in the control of electrical drives is the demand for a high control performance. In addition to a short settling time and a small setpoint deviation, a low current ripple is desired. The unavoidable ripple is caused by the switching principle of the used voltage-source inverters. The consideration of the ripple when determining the actuating variables differs between the established control approaches such as the field-oriented control (FOC), the finite-control-set (FCS), or the continuous-control-set (CCS)model predictive control (MPC). This also depends on whether a dedicated modulator is used or not. A CCS-MPC with integrated modulator which takes the principle of a pulse width modulation-like modulator (PWM)during optimization into account is presented. The setpoint deviation and the current ripple are the objectives of a optimization problem. Here, choosing an appropriate cost function is investigated such that the performance in steady state is comparable to that of a FOC and during transients to that of a MPC approach. The chosen cost function also defines the class of the optimization problem to be solved online in each controller cycle. Besides a simulative investigation, an experimental setup with a permanent magnet synchronous motor (PMSM)and qpOASES as solver for real-time optimizations was implemented.