Multiphase Induction Motor Temperature Field Analysis And Calculation

In low-voltage large power driving systems with high reliability, such as submarine power systems and nuclear power plant cooling systems, the multi-phase induction motor has been widely used. In order to ensure the motor efficient and safe, the internal temperature rise has to be accurately calculated and some temperature rises of the motor has to be controlled within the scope of design. In this paper, the numerical calculation of stator and rotor temperature by the finite element method in the induction motor with non-sinusoidal supply is presented.To get the convective heat transfer coefficients of the stator radial cooling channel surfaces, the fluid field and temperature field indirect coupling method has been employed in the multi-phase induction motor stator, which aims to heat transfer characteristics analysis and calculation. Based on the fluid dynamics theory, a three-dimensional mathematical model of the incompressible viscous turbulent fluid flow around objects in the stator radial cooling channel is established. The non-uniform fluid velocities along radial and circumferential directions are obtained by the finite volume method. Compared with the fluid flow around non-object in the stator radial cooling channel, the calculated results are validated to be accurate. Consequently, the influence of the inlet air velocity on fluid distribution in the radial cooling channel is investigated.By means of the numerical calculation of the fluid field in the stator radial cooling channel, the convective heat transfer coefficients are obtained, and the stator three-dimensional temperature field is solved. The numerical calculation result is compared with the result by traditional method, which considers the convective heat transfer coefficients of the radial cooling channel surfaces as constants. Furthermore, other effects on the stator three-dimensional temperature field are researched, such as inlet fluid flow velocity, the number of the radial cooling channel and different isolated layer models.Finally, the three-dimensional temperature field models of the rotor two cooling system design are established. According to the calculated results, the optimal rotor cooling system design is determined. In addition, some effect factors in rotor temperature field are studied, for instance, the change of the rotor speed, the radial cross-section size and the geometry changes of the axial cooling channel and the quantitative change of the rotor axial cooling channel. Research results on the optimized design of the multi-phase induction motor stator and rotor cooling system are of some guiding significance.