Vector Control Technology of Five-Phase Induction Motor without Speed Sensor Based on Speed-Adaptive Full-Order Observer

The five-phase induction motor, being the most elementary form of multiphase induction motors, boasts low noise, low torque fluctuations, and high load-bearing capacity, and is hence suitably employed in domains where high power and reliability are required. In light of the susceptibility of the speed encoder to interference from external environments, this paper proposes a sensorless vector control technique for the five-phase induction motor based on a speed-adaptive full-order observer. The proposed approach first employs the nearest four-vector space vector pulse width modulation (NFV-SVPWM) as the modulation technique for the five-phase inverter, in order to provide a constant switching frequency and low harmonic losses. Subsequently, the expression for the speed-adaptive full-order observer is constructed based on the mathematical model of the fundamental space of the five-phase induction motor, and the expression for the adaptive speed law is deduced using the Lyapunov function. Additionally, the bilinear transformation method is utilized as the discretization technique for the full-order observer during the process of digital implementation, in order to achieve higher discrete accuracy. Finally, an experimental study involving a 4.5kW five-phase induction motor was conducted to validate the accuracy and effectiveness of the proposed method. (c) 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.