Sensorless Control of Oil-submersible IPMSM with MTPA Strategy over Full Speed Range

This paper presents a study on high reliability, energy efficient control of oil-submersible interior permanent magnet synchronous motor (IPMSM). A full order sliding mode observer (FSMO) is utilized to estimate rotor position/speed in the medium to high speed region, enabling fully sensorless control. In the zero to low speed region, an I/F open loop drive enhanced by a frequency compensation loop is implemented, thereby obviating the need for more intricate sensorless vector control. A Seamless switching between the two schemes is achieved via dual dq frame switching. To fully exploit the motor’s torque potential, a maximum torque per current (MTPA)strategy combining pre test operating points with equivalent variable parameters is used to allocate dq axis currents. The complete control framework is validated through MATLAB/Simulink simulations, which confirm its effectiveness.