The embodiment of the invention provides a method for calculating a
heat transfer ratio based on the
eddy current loss of a rotor segmented sheath of a
permanent magnet motor. The method comprises thefollowing steps: separately establishing a field circuit
coupling calculation model with a segmented sheath and a field circuit
coupling calculation model without sheath for the
permanent magnet motor based on
vector control, and calculating the loss of each component; then, separately establishing a three-dimensional
steady state temperature field solution model with a segmented sheath and a three-dimensional
steady state temperature field solution model without sheath for the
permanent magnet motor, determining a boundary condition based on an assumed condition, and obtaining a rotor steadystate heat
conduction equation; separately calculating a heat
conductivity coefficient in an air gap and the heat
conductivity coefficient of a
stator winding, substituting the heat
conductivity coefficients in the rotor
steady state heat
conduction equation, and using the loss as the heat source of a solution domain to obtain a
steady state temperature field of the permanent
magnet motor; and separately calculating the temperature of each component under the action on basic wave current on the permanent
magnet motor in which the rotor has no sheath and the permanent
magnet motor in which therotor has the segmented sheath, and calculating the
heat transfer ratio of each component according to the temperature of each component. The method provided by the invention provides important theoretical basis for the design of an electromagnetic structure of the permanent magnet motor.