Advanced fault-tolerant current control of five-phase PMSM for mining applications

The next big change in mining technology is associated with using more power dense motors, such as permanent magnet synchronous motors (PMSM). For added robustness and fault tolerance, multiphase PMSM can be recommended. Focus of this paper is development of an advanced current control scheme for five-phase PMSM under normal conditions and one-phase open-fault. While traditional linear controllers can cope well with current reference tracking in the healthy motor conditions, but post fault operation involves unmodelled dynamics, which significantly reduces the effectiveness of linear controllers. The proposed non-linear control scheme is based on decoupled fault motor model and sliding mode control (SMC). It is capable of providing constant d and q axis current and constant back-EMFs, even if the motor is missing one phase. With this approach the faulty motor has a smooth output speed profile. This makes it efficient and suitable for demanding drive applications, such as mining machinery. Feasibility of the proposed control strategy is experimentally verified on a FPGAIDCS based five-phase PMSM drive.