Sensorless control of PMSM based on third harmonic back EMF and SOGI-FLL

The article discusses the challenges and limitations of traditional sensor-based control methods for Permanent Magnet Synchronous Motors (PMSMs), focusing on the development of a novel sensorless control method based on third harmonic back EMF and SOGI-FLL. This method aims to overcome the drawbacks of existing techniques by providing high accuracy and low cost, making it particularly suitable for applications in aerospace, electric vehicles, and household appliances. The authors analyze the relationship between neutral point voltage and third harmonic back EMF, presenting a new detection circuit and sampling method that significantly reduces hardware costs. The proposed method also includes a cascaded filter to effectively remove switching spike signals and sampling noise. The use of SOGI-FLL allows for accurate position estimation and filtering of non-third harmonic back EMF caused by the asymmetry of three-phase back EMFs. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed method, showing excellent static and dynamic performance across a wide range of speeds and loads. This article is a must-read for professionals seeking innovative solutions in the field of motor control and automation.