U-shaped composite permanent magnet motor

Abstract

The invention relates to a U-shaped composite permanent magnet motor, which relates to the technical field of motors and aims to improve the weak magnetic speed-increasing capability. The motor comprises a stator and a rotor, wherein a plurality of permanent magnet units which are symmetrically distributed around the axis of the rotor are arranged on the rotor, and each permanent magnet unit comprises a middle permanent magnet groove and two side permanent magnet grooves; a composite magnet is inlaid in the middle permanent magnet groove and is formed by laminating a first permanent magnet anda second permanent magnet, the first permanent magnet is positioned at the outer side of the second permanent magnet, and the coercive force of the first permanent magnet is greater than that of thesecond permanent magnet; third permanent magnets are inlaid in the side permanent magnet grooves, the coercive force of each third permanent magnet is the same as that of the first permanent magnet, the arrangement shape of the two third permanent magnets is a splayed shape with inward narrow openings, and the composite magnets are arranged at the narrow opening portions of the splayed shapes. Themotor provided by the invention can meet the driving requirements of electric automobiles and hybrid electric automobiles.

Description

technical field [0001] The invention relates to motor technology, in particular to a U-shaped compound permanent magnet motor technology. Background technique [0002] Electric vehicle drive systems all use the built-in permanent magnet synchronous motor (IPMSM) as the power source. The built-in permanent magnet synchronous motor is excited by permanent magnets, and its magnetic field is constant and cannot be adjusted. When the parameters and size of the motor are constant, the speed increases with the increase of the voltage. In the constant power operation area above the base speed, as the speed increases, due to the limitation of the supply voltage (the motor for electric vehicles is powered by batteries), it is difficult to increase the speed with constant power; In addition, on the direct axis (d axis) of the motor, the magnetic permeability of the permanent magnet is close to that of air, and the direct axis inductance Ld is small, which increases the difficulty of in...

AI Technical Summary

Problems solved by technology

[0002] Electric vehicle drive systems all use built-in permanent magnet synchronous motor (IPMSM) as the power source. The built-in permanent magnet synchronous motor adopts permanent magnet excitation, and its magnetic field is constant and cannot be adjusted.

When the parameters and size of the motor are constant, the speed increases with the increase of the voltage. In the constant power operation area above the base speed, as the speed increases, due to the limitation of the supply voltage (the motor for electric vehicles is powered by batteries), it is difficult to increase the speed with constant power; In addition, on the direct axis (d axis) of the motor, the magnetic permeability of the permanent magnet is close to that of air, and the direct axis inductance Ld is small, which increases the difficulty of increasing the speed of magnetic field weakening

[0003] The existing built-in permanent magnet synchronous motor must obtain the reluctance torque by adjusting the stator current (that is, increasing the stator direct axis demagnetization current component -Id) through field weakening, and the weakening of the air gap magnetic field of the motor is equivalent to the direct Weaken the excitation magnetic field to achieve field weakening. The speed expansion range of field weakening is narrow, the stator loss is large, the efficiency of the system (motor and controller) is low, and increasing the direct-axis armature current-Id will lead to the risk of irreversible demagnetization of the magnet steel. Thicken the magnet steel It will increase the centrifugal force and cost of the rotor

Therefore, the existing built-in permanent magnet synchronous motors have defects such as low power and torque density, narrow range of high-speed constant power, large torque fluctuations, low overload capacity and system efficiency, high risk of magnet demagnetization, and poor reliability. The research and development of drive motor and its industrialization progress

Images