Split type combined permanent magnet brushless motor for electric vehicle

Abstract

The invention discloses a split type combined permanent magnet brushless motor for an electric vehicle. A rotor is coaxially positioned in the internal of a stator; a rectangular neodymium iron boron permanent magnet steel and two same rectangular ferrite permanent magnet steels are fixedly embedded in each pole of the rotor; the neodymium iron boron permanent magnet steels are close to air gaps and are symmetrical relative to the central line of the rotor poles; the two ferrite permanent magnet steels are close to a rotation shaft, are distributed on the two sides of the central line of the rotor poles and are symmetrical relative to the central line of the rotor poles; a magnetic conductive bridge is between the two ferrite permanent magnet steels; the permanent magnet steel on each pole is magnetized along the tangential direction of the circumference; the magnetizing directions on the same pole are the same, and the magnetizing directions on the adjacent two poles are opposite; the rare earth permanent magnet material and the non-rare-earth ferrite permanent magnet material are adopted at the same time; on the basis of ensuring the power density and the torque density of the permanent magnet motor with a small amount of rare earth, the cost of the motor is reduced by more than 50%; and in addition, the requirements on the torque and the power in the electric vehicle applications can be met on the premise of keeping the relatively high power density and the torque density.

Description

technical field [0001] The invention relates to a permanent magnet synchronous motor, which belongs to the field of motor manufacturing and control, in particular to a permanent magnet synchronous motor suitable for traction hybrid vehicles, electric vehicles and other applications that require wide speed regulation, high efficiency, high power density and other drive performance requirements. Magnetic brushless motor. Background technique [0002] With the improvement of the performance of permanent magnets, rare earth permanent magnet motors based on NdFeB have been widely used in hybrid vehicles, electric vehicles and other fields due to their advantages such as high power density and high efficiency. In recent years, the over-exploitation of rare earth minerals has not only greatly reduced the reserves of rare earths, but also caused serious damage to the ecological environment. In order to protect rare earth resources and the increase in demand for rare earth permanent...

AI Technical Summary

Problems solved by technology

However, since the reluctance torque accounts for the main part of the output torque, the torque ripple of the permanent magnet assisted synchronous reluctance motor is relatively large

In the document "Rotorstructure in 50kW spoke-type interior permanent magnet synchronous motor with ferrite permanent magnets for automotive applications" (published in IEEE Energy Conversion Congress and Exposition in 2013, pages 606-613), the power density of the motor is improved by adding an air gap to the traditional spoke-shaped ferrite motor rotor, but the reluctance torque is used The mechanical strength of the machine is also reduced, and there is a risk when running at high speed

In order to ensure a certain power density, ferrite permanent magnet motors generally need to use a large amount of ferrite permanent magnet materials, which will reduce the direct-axis inductance of the motor, thereby affecting the motor's ability to increase speed with weak magnetic field, and is not suitable for high-speed motors. run

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