Full Torque–Speed Range Minimum Loss (FT-SRML) Fault-Tolerant Control of Dual Three-Phase PMSMs Under Open-Phase Fault

When dual three-phase PMSM (DT-PMSM) operates under open-phase fault, the harmonics in the post-fault currents could substantially degrade system efficiency, maximum torque range and maximum speed range. Existing full torque range minimum loss (FTRML) fault-tolerant controls (FTCs) consider the current magnitude limit to achieve the extended torque range with minimum loss. However, full speed range minimum loss (FSRML) is not achieved yet. Thus, this paper proposes a full torque-speed range minimum loss (FT-SRML) FTC, which combines proposed FSRML and existing FTRML, and thus can be used in the full torque speed range with minimum loss. In the proposed FTC, the zero ripple post-fault currents are designed and optimized to achieve minimum loss in full torque-speed range by considering peak phase current (PPC) and peak phase voltage (PPV) constraints. Moreover, the optimal solutions are analytically derived in not only full torque range but also full speed range with high computational efficiency. Compared with existing FTCs, the proposed FT-SRML FTC is applicable to full torque and speed range and achieves minimum loss with higher computation efficiency. Extensive experiments and comparisons on a test DT-PMSM are conducted to validate the proposed FTC.