Design and thermal network modeling of BLDC motor for submersible pump application

Abstract

This paper presents the design and thermal analysis of surface-mounted brushless motor (SMBLDC) for submersible pump applications. SMBLDC motor is used due to its high efficiency and low torque to weight ratio in comparison to conventional motors. For a submersible pump application, bore well size and motor diameter are the main constraints. Following the MNRE, GOI guidelines concerned with submersible pumps, all the machine parameters are numerically evaluated, and then its 2D FEA analysis is carried out in the ANSYS/Maxwell environment. The designed motor has obtained good flux concentration and low cogging torque. Then the thermal analysis is performed to examine the temperature rise in different parts of the motor. Thermal network modeling of the motor is proposed to carry out the steady-state and transient thermal analysis, which is performed in Motor-CAD software. Thermal runaway conditions are observed in the steady-state analysis with a severe increase in the temperature of windings and magnets. As submersible pumps are subjected to steady-state operations, a cooling arrangement is also proposed to keep the temperature rise within the acceptable range avoiding insulation failure or magnet losing its properties.