Motor control method for irregular carrier slope random modulation

Abstract

The invention discloses a motor control method for irregular carrier slope random modulation. The implementation of the method comprises four parts: a three-phase motor, a voltage-source inverter bridge, a modulated wave generating module and a random PWM generating module. The random PWM generating module calculates six comparison values in one cycle by comparing the value of a random variable corresponding to a fixed sawtooth carrier when the irregular carrier slope is random; and then comparing the calculated comparison value with a sawtooth carrier to generate a random PWM pulse. The implementation method of the irregular carrier slope random modulation does not require an external additional circuit, has universality, is small in calculation, is easy to implement in engineering, can uniformly distribute a phase current spectrum in a wide range while maintaining the sampling frequency unchanged, and reduces the harmonic amplitude at an integer multiple of the switching frequency toachieve a purpose of suppressing electromagnetic interference of the system and reducing the high and low frequency vibration of the motor.

Description

technical field [0001] The invention relates to a motor control method for random modulation of irregular carrier slope, which belongs to the field of motor control. Background technique [0002] With the rapid development of industry and technology, vibration noise and electromagnetic interference (EMI) during motor operation have become the current focus and urgent problems to be solved. When the motor is powered by variable frequency, the pulse width modulation control will introduce a large number of current harmonics in the armature winding, which will cause the motor to generate obvious vibration noise at integer multiples of the switching frequency, which will also aggravate the electromagnetic interference of the motor and affect the overall performance of the electromechanical system. Different motor control methods have different magnitudes and distributions of phase current harmonics, so problems such as motor vibration and electromagnetic interference can be supp...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of high motor phase current and low frequency harmonic amplitude caused by the traditional fixed triangular carrier pulse width modulation, which cause relatively large high and low frequency vibration and electromagnetic interference of the motor, and propose an irregular carrier slope Randomly modulated motor control method, the method has obvious suppression effect on motor vibration, and the sampling frequency is constant, easy to implement in engineering, does not require hardware auxiliary circuits, and has universal applicability

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