Air conditioner or compressor for refrigerator driven by permanent magnet synchronous motor

Abstract

An air conditioner or a refrigerator compressor is driven by a permanent magnet synchronous motor with a stator of a concentrated winding mode, the interval between the pole pieces of the stator (1) is La, the stator (1) and the rotor (2 ) is Lg, so that 0.3Lg<La≤2.0Lg, or, assuming that the pole shoe end thickness of the permanent stator (1) is Lb, the air gap between the stator (1) and the rotor (2) is Lg , and make 2Lg<Lb<5Lg. In addition, the outer peripheries of both circumferential end portions of the permanent magnets (6) provided on the outer peripheral portion of the rotor (2) may be formed in a concave shape that is recessed radially inward from the outer periphery of the rotor. In this way, it is difficult for the demagnetization field to act on the permanent magnet (6), thereby improving the demagnetization resistance of the permanent magnet (6).

Description

[0001] This application is a divisional application with the application number 02105150x, the filing date being September 7, 1998, and the name being "compressor for air conditioner or refrigerator driven by permanent magnet synchronous motor". technical field [0002] The present invention relates to a compressor for an air conditioner or a refrigerator, which is driven by a permanent magnet synchronous motor whose rotor is provided with a permanent magnet for generating a magnetic field, and in particular to an air conditioner driven by a permanent magnet synchronous motor with a stator having a concentrated winding method Or a compressor for a refrigerator. Background technique [0003] Compressors for air conditioners or refrigerators are generally driven by permanent magnet synchronous motors. In general, high-power permanent magnet synchronous motors increase the number of teeth of the stator and adopt a distributed winding method to make the synthetic magnetomotive f...

AI Technical Summary

Problems solved by technology

[0004] However, the distributed winding method has problems in that the winding process is complicated and the winding efficiency is low, and the rare earth magnet is expensive, and the sensor for detecting the rotation phase is also expensive, so the cost is high

[0010] So far, although there have been many motors with concentrated winding methods, when the pole piece spacing is very narrow and the polarities of adjacent pole pieces are opposite, the permanent magnet is easily demagnetized. If a permanent magnet with a small coercive force such as ferrite is used Magnets, the ability to resist demagnetization becomes weak

Especially in the case of sensorless driving, there is a high possibility of being subjected to a reverse magnetic field at the time of starting and out of step, and there is a problem that it is extremely easy to demagnetize

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