Fault-Tolerant Method of Current Reconstruction for Open-end Winding Permanent Magnet Synchronous Machine Electric Propulsion System with Open-Phase Operation

In order to enhance the reliability and security of the open-end winding permanent magnet synchronous machine (OEW-PMSM) electric propulsion system, a current reconstruction fault-tolerant method based on traditional space vector pulse width modulation method(SVPWM) is proposed, characterized by reducing the immeasurable regions in the high modulation region. Firstly, an installation method of DC bus current sensor is proposed to measure zero sequence current(ZSC), which is essential for fault-tolerant operation. Then, in the single-vector immeasurable regions of the high modulation region, the sum of the remaining non-fault phase currents is sampled and used to calculate the ZSC. The reconstruction of phase currents is realized through estimation and correction based on ZSC. And in the dual-vector immeasurable regions of the high modulation region, the sufficient DC bus current sampling time can be provided to realize data acquisition with ZSC by reallocating the action time of two voltage vectors with the same effect, and the phase currents are reconstructed. The proposed method maintains a symmetrical PWM waveform within one control cycle, which can be generated using a standard triangular carrier, thus avoiding additional harmonics and reducing computational burden while facilitating easy implementation in existing digital controllers. Finally, the effectiveness of the proposed method in fault-tolerant operation has been verified through experiments, improving the fault-tolerant capability of the electric propulsion system.