Rotor of built-in permanent magnet motor and magnetic steel structural parameter determining method thereof

Abstract

The invention relates to a rotor of a high-quality and high-speed built-in permanent magnet motor and a magnetic steel structural parameter determining method thereof. In the invention, the whole section magnetic steel of each electrode of the rotor of a conventional built-in permanent magnet motor is divided into multiple sections of magnetic steel which have the same polarity and different widths; the multiple sections of the magnetic steel are respectively arranged in a rotor core; and reinforcing ribs with the function of magnetic isolation are arranged among the multiple sections of the magnetic steel. By reasonably modulating and determining the width and distribution of each section of the magnetic steel, the air gap magnetic density waveform approaches sine distribution; harmonic components are reduced to the greatest extent; the eddy current loss of the magnetic steel and the torque pulsation of the motor are simultaneously reduced; and the electromagnetic performance of the motor is enhanced. Furthermore, the multiple sections of the magnetic steel are arranged in the circumference along the rotor; the highest rotating speed of the safe operation of the rotor is greatly enhanced on machinery; the radial thickness which is needed by the magnetic circuit of the rotor is obviously reduced on the structure; the rotational inertia and weight of the rotor are reduced; the dynamic response of the motor is improved; and the requirements of a high-speed driving system on the performance of the motor are met.

Description

technical field [0001] The invention relates to a rotor of a built-in permanent magnet motor, in particular to a high-quality high-speed built-in permanent magnet motor rotor and a method for determining its magnetic steel structure parameters. Background technique [0002] With the rapid development of industrial technology and permanent magnet materials, built-in permanent magnet motors have increasingly broad application prospects in high-speed servo systems such as precision CNC machine tools, machining centers, and industrial robots. At the same time, more stringent requirements are put forward for the mechanical and electromagnetic performance of the interior permanent magnet motor. It is necessary to pursue high stiffness, small inertia, and light weight to meet the requirements of high dynamic response and high power / torque density of the system; it is also necessary to suppress the harmonic components in the air-gap magnetic field to achieve low torque ripple and lo...

AI Technical Summary

Problems solved by technology

However, when running at high speed, the conventional permanent magnet motor with built-in rotor structure also has obvious shortcomings. Taking the "I" type built-in rotor as an example, the main performances are as follows: 1) Due to the long moment arm of the rotor centrifugal force distribution load, the large The bending moment causes a large stress at the magnetic isolation bridge and a large deformation at the middle position of the adjacent magnetic isolation bridge, and the stress and deformation increase rapidly with the increase of the rotational speed

Restricted by the yield strength of the rotor silicon steel sheet and the length of the air gap of the motor, it is difficult to increase the maximum safe operating speed of the motor; 2) The sine degree of the air gap flux density waveform is difficult to adjust, and the harmonic component is large, which affects the torque ripple of the motor, Vibration, noise, efficiency and other performance indicators; 3) The structural and magnetic reasons restrict the minimum size of the silicon steel sheet, and the radial thickness of the rotor is relatively large, which increases the weight and moment of inertia of the rotor

Therefore, surface-mounted and conventional built-in rotor structure permanent magnet motors are difficult to meet the requirements of the drive system for motors under high-speed operating conditions

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