Fault-Tolerant Predictive Current Control of Six-Phase PMSMs With Minimal Reconfiguration Requirements

By manipulating the additional degrees of freedom of multiphase machines, inherent to this type of machine, fault-tolerant control strategies are able to keep multiphase drives in service after one or more open-phase faults (OPFs). Therefore, multiphase machines controlled by finite control set model predictive control (FCS-MPC) strategies are an excellent fit for critical systems, where reliability and excellent dynamic performance are necessary. However, the existing fault-tolerant FCS-MPC strategies typically require considerable changes to the structure of the control algorithm when transitioning between healthy and fault-tolerant modes of operation. Therefore, this article proposes a novel fault-tolerant predictive current control (FT-PCC) strategy with minimal reconfiguration requirements for the six-phase permanent magnet synchronous machine (PMSM) drives. The proposed method only requires the adjustment of current references during fault-tolerant operation and keeps the structure of the control algorithm unchanged. To validate this FT-PCC strategy, several simulation and experimental results are presented for different OPF scenarios, in which the excellent performance obtained with the proposed method is demonstrated.

I. Introduction

Multiphase machines offer unique fault-tolerant capabilities as they can remain in operation after the occurrence of single or multiple open-phase faults (OPFs) without requiring any additional hardware [1]. Furthermore, since the decoupled regulation of flux and torque in multiphase machines only requires the control of two independent currents, i.e., two degrees of freedom, their remaining degrees of freedom can be manipulated to guarantee a disturbance-free operation during post-fault conditions [2]. In addition, multiphase electric drives provide several advantages over the three-phase drives, such as lesser torque harmonics, reduced power ratings per phase, lower cabling costs, and smaller dc-link capacitors [3], [4].