A Carrier Self-Synchronization Method for Distributed Control Units in Multithree-Phase Permanent Magnet Synchronous Motor

The multithree-phase permanent magnet synchronous motor (MTP-PMSM) has garnered significant attention due to its advantages, including reduced torque oscillations, lower power rating per phase, and improved fault tolerance. The control architecture of MTP-PMSM can be categorized into a centralized and distributed structure depending on the number of controllers used. The distributed control architecture proves increasingly advantageous as the number of phases in MTP-PMSM increases, owing to its modular configuration. However, minor differences in crystal oscillator frequencies among controllers may lead to pulse width modulation (PWM) carrier phase desynchronization, resulting in increased current harmonics. Conventional methods for synchronizing carrier phases in controllers rely on hardware communication systems, which not only increase the complexity of the controller, but also degrade the reliability of system. In response, our article proposes a carrier phase self-synchronization method devoid of hardware synchronization devices. The proposed method utilizes the amplitude difference between upper and lower sideband harmonic currents sampled by distributed controllers for synchronization. This carrier self-synchronization method was validated through experimentation with the dual three-phase permanent magnet synchronous motor (DTP-PMSM).