Permanent-magnet synchronous motor and compressor using this

Abstract

A permanent-magnet synchronous motor provided with a rotor structure having cage-type windings and a permanent magnet disposed on the inner peripheral side of the cage-type winding bar, wherein the permanent magnet is magnetized to provide a ratio theta / alpha of 0.54 through 0.67 between the peripheral-direction pitch angle theta of the permanent magnet's magnetic flux distribution and a magneticpole pitch angle alpha so as to ensure a required induced electromotive force with no increase in iron loss and to reduce a waveform distortion rate. Accordingly, a high-efficiency permanent-magnet synchronous motor can be provided due to an induced electromotive force having little distortion and a shape of nearly a sinusoidal wave.

Description

Permanent magnet synchronous motor and compressor using it technical field The invention relates to a permanent magnet synchronous motor and a compressor using it. Background technique The advantage of the induction motor is that it not only has a solid structure, but also can be started by directly turning on a commercial power supply, and can be configured at low cost as a driving source for a constant-speed drive that does not require speed control. On the other hand, like an induction motor, a synchronous motor not only has a low-cost configuration of the drive unit, but also has the advantage that it greatly contributes to the high efficiency of the drive system because there is almost no secondary copper loss during normal operation. However, as a disadvantage, there is a cage winding for starting on the outer peripheral side of the rotor, and it is necessary to further arrange permanent magnets on the inner peripheral side of the cage conductor, which limits the sp...

AI Technical Summary

Problems solved by technology

In the case of the latter, there are many cases where the waveform distortion is also increased, and the characteristics are deteriorated.

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