This article proposes an open-circuit fault-tolerant strategy for a dual-three-phase synchronous reluctance motor (DTP-SynRM) based on rotation coordinate transformation. A DTP-SynRM vector space decoupling model is established to achieve complete decoupling of voltage, current, and flux equations. Then, the influence of the fault state on the current and the torque fluctuations of the motor is analyzed. The proposed fault-tolerant strategy converts the second harmonic of the current through rotational coordinate transformation, thereby directly controlling the second harmonic of the current using a proportional-integral regulator in the new coordinate system. The simulation results prove the analysis and the effectiveness of the proposed strategy.

This article focuses on the one-phase open-circuit fault in a dual three-phase synchronous reluctance motor (DTP-SynRM). Firstly, a mathematical model of the DTP- SynRM is established, Then the influence of the open-circuit fault on the voltage and current of the DTP-SynRM is analyzed. Afterwards, a fault-tolerant control method based on rotating coordinate transformation is proposed, which converts the secondary current harmonics through rotating coordinate transformation, so that the second current harmonics can be directly controlled by using a PI controller in the new coordinate system. Finally, the feasibility and effectiveness of the proposed fault-tolerant strategy are verified by simulation experiments.

The advantage of Dual three-phase Permanent Magnet Synchronous Motors (DTP-PMSMs) is their excellent fault tolerance ability. However, the complex fault-tolerant controller structure and the high torque ripple when operating after failure limit their further development. This paper develops a fault tolerant control scheme for DTP-PMSMs under open-phase faults (OPFs) with only 3 current loops and smooth output torque. The proposed controller structure can remain basically unchanged as normal operation and appropriate voltage compensation is deduced and employed to suppress the torque ripple induced by OPF. Simulation and experiment results demonstrate the analysis and the validity of the proposed strategy.

Dual-three-phase permanent magnet synchronous machines (DTP-PMSMs) are famous for their fault-tolerant capability. However, the complex modeling, high copper loss, and torque ripple under postfault operation limit their further application. In this article, a fault-tolerant control (FTC) strategy is developed for DTP-PMSMs under the open-phase fault (OPF) with straightforward modeling and smooth output torque. The virtual healthy DTP-PMSM model, where the coordinate transformation, the modulation strategy, and the controller structure remain unchanged under OPF, is adopted in the proposed FTC scheme. And the current references are derived in sinusoidal waves with minimum copper loss. The inaccurate transmission of control signals under OPF is also focused on. Comprehensive theoretical analysis shows the relationship between the controller output voltage and the actual stator voltage should be considered in the proposed FTC strategy; otherwise, distortion in torque and current will be introduced. The voltage compensation is utilized to compensate for the voltage difference and ensure the smooth torque output. Besides, a quasi proportional resonance controller is designed to further suppress the residual torque ripple. The proposed strategy will not induce complex implementation and heavy computation burden. The simulation and experimental results prove the analysis and the effectiveness of the proposed strategy.

When the control strategy of permanent magnet synchronous motor (PMSM) is switched from open-loop control to closed-loop control, direct switching will result in some side effects, such as large current, torque and speed fluctuations. Aiming at these problems, a control strategy of switching method based on linear weight change is proposed. The contribution of this work is: both the gradual reduction of the angular difference and the smooth switching from open-loop to closed-loop are taken into account. Current, speed, and torque fluctuation caused by switching are eliminated. The effectiveness is demonstrated by simulation and experimental results.