A Novel Speed Sensor-less Control of a Solar-Powered PMSM Drive

This paper proposes a novel control methodology for the solar-powered motor drive of a surface-mounted Permanent Magnet Synchronous Motor (SPMSM). Standalone solar-powered motor drives face considerable challenges due to inherent PV power fluctuations and the absence of an external energy storage system. These challenges are further exacerbated with solar microinverters utilizing a low DC link capacitance due to the limited energy storage capacity of the DC link. Reliable operation under such conditions requires a control strategy that optimally utilizes fluctuating solar power while maintaining stability during input power and load transients, despite the low DC link stiffness. The proposed control strategy quickly modulates the drive frequency to follow the Maximum Torque per Ampere (MTPA) trajectory while the current reference is directly set by DC link voltage regulation. Compared to existing observer-based vector control methods, the proposed approach offers fast dynamic performance, simplified implementation, and eliminates the need for a separate startup routine.