Permanent magnetic synchronous motor system, field weakening control method thereof, and field weakening control device thereof

Abstract

The invention discloses a permanent magnetic synchronous motor system, a field weakening control method thereof, and a field weakening control device thereof. The field weakening control method comprises steps that a first output voltage ud/uq under the rotating coordinate system of the permanent magnetic synchronous motor system or a second output voltage u alpha/u beta under the static coordinate system of the permanent magnet synchronous motor system, and an expected output voltage us is acquired according to the first output voltage u d/ u q or the second output voltage u alpha/u beta; a voltage amplitude limiting threshold value is acquired according to the output voltage us, and field weakening current is generated according to the amplitude of the expected output voltage us and the voltage amplitude limiting threshold value; the field weakening current is superposed with the direct axis current closed loop of the permanent magnetic synchronous motor system to carry out the field weakening control over the permanent magnetic synchronous motor system, and in addition, a field weakening control bandwidth is smaller than the bandwidth of the direct axis current closed loop, and is greater than double of frequency of an alternating current power supply input in the permanent magnetic synchronous motor system. The responding speed of the field weakening control is guaranteed, and by fully using a fluctuating direct current busbar voltage, maximum motor efficiency operation is achieved during the fluctuation of the direct current busbar voltage.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a field-weakening control method for a permanent magnet synchronous motor system, a field-weakening control device for a permanent magnet synchronous motor system, and a permanent magnet synchronous motor system. Background technique [0002] Permanent magnet synchronous motors have been widely used in various industries due to their good control performance, high power density, and energy saving. Among them, in many applications, permanent magnet synchronous motors are required to operate in the high frequency range, and then run in the field weakening range, such as variable frequency compressors based on permanent magnet synchronous motors, fans based on permanent magnet synchronous motors, etc. The field weakening control method in the related art is usually based on the DC bus voltage, but there is a problem that the fluctuation of the DC bus voltage will affect the fi...

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Problems solved by technology

The field weakening control method in the related art is usually based on the DC bus voltage, but the problem is that the fluctuation of the DC bus voltage will affect the field weakening control of the permanent magnet synchronous motor, resulting in too large or too small field weakening depth

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