Design method of electric roller with high torque density

The invention provides a design method of an electric roller with high torque density, the electric roller comprises an outer rotor permanent magnet driving motor and a roller, the outer rotor permanent magnet driving motor is a magnetic field modulation permanent magnet motor, and the design method comprises the following steps: 1, determining rated torque according to an task book index; 2, according to the cooling condition of the motor, preliminarily selecting the current density of a line load and a wire, and according to the capacity grade of the motor, preliminarily selecting the flux density of an air gap and the flux density of stator teeth; 3, preliminarily determining structural parameters of a stator, a rotor and magnetic steel of the outer rotor motor by adopting a field circuit analysis method; fourthly, according to the preliminarily determined structural parameters of the stator, the rotor and the magnetic steel, finite element software is adopted for simulation, the flux density and performan