Position Sensorless Control of Multiphase PMSM Based on Harmonic Back-EMF Observation

Position sensorless control not only reduces the cost and size of motor control systems, but also enhances control system stability. These advantages have made it a prominent research topic in the realm of permanent magnet synchronous motor (PMSM) control. This paper proposes a strategy for position sensorless control of a multiphase PMSM, where the mathematical model of a nine-phase PMSM is derived in different coordinate systems, and the rotor position is extracted by observing the harmonic back-EMF. The sensorless control system of the nine-phase PMSM is designed in detail, and the proposed method in this paper is verified by experiments.