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Hysteresis random spectrum spreading method in inverter random pulse width modulation selective resonance elimination

A pulse width modulation and inverter technology, applied in the direction of output power conversion device, AC power input conversion to DC power output, electrical components, etc., can solve the problem of controlling the instantaneous switching frequency and average switching frequency of the inverter, Issues such as the switching period and the general formula of random numbers are not given, achieving the effect of simple algorithm, easy implementation, and strong control flexibility

Active Publication Date: 2021-10-22
LIAONING TECHNICAL UNIVERSITY
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AI Technical Summary

Problems solved by technology

The existing relevant literatures do not consider how to control the instantaneous switching frequency and the average switching frequency of the inverter when realizing selective harmonic elimination; nor do they give general formulas for the switching period, random number and the corresponding upper and lower limits of frequency. Lack of systematic analysis of the elimination mechanism for specific sub-frequency

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  • Hysteresis random spectrum spreading method in inverter random pulse width modulation selective resonance elimination
  • Hysteresis random spectrum spreading method in inverter random pulse width modulation selective resonance elimination
  • Hysteresis random spectrum spreading method in inverter random pulse width modulation selective resonance elimination

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Embodiment 1

[0039] A hysteresis random spread spectrum method in random pulse width modulation selective harmonic elimination of inverters, such as figure 1 shown, including the following steps:

[0040] Step S1: Based on each cycle frequency f of the inverter m The summation is performed to obtain the average value f of the inverter switching frequency An ;

[0041] Step S2: Set the frequency hysteresis upper and lower limits f 1 and f 2 ;

[0042] Step S3: The average value of the inverter switching frequency f An with the upper and lower limits of the frequency hysteresis f 1 and f 2 Perform comparison to obtain hysteresis comparison results;

[0043] Step S4: Determine the average switching frequency error Δf according to the hysteresis comparison result;

[0044] Step S5: Determine a random number k according to the value of the switching frequency error Δf;

[0045] Step S6: Based on the random number k and the method of selective harmonic elimination, the sampling period T ...

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Abstract

The invention provides a hysteresis random spectrum spreading method in inverter random pulse width modulation selective resonance elimination, and belongs to the technical field of inverter pulse width modulation. The method comprises the steps: carrying out the summation based on the frequency of each period of an inverter, and obtaining an average value of the switching frequency of the inverter; setting upper and lower limits of frequency hysteresis; comparing the inverter switching frequency average value with the frequency hysteresis upper and lower limits to obtain a hysteresis comparison result; determining an average switching frequency error according to a hysteresis comparison result; determining a random number according to the value of the switching frequency error; obtaining a sampling period of the next moment based on the random number and a selective harmonic elimination method; and according to the sampling period of the next moment, assigning a value to a comparison register, and generating a PWM driving signal of the single-phase inverter. According to the invention, the harmonic waves which are centrally distributed at the switching frequency and the integral multiple of the switching frequency can be uniformly distributed in the selected frequency range, and random PWM control is realized, so that the harmonic waves at the specific frequency can be selectively reduced.

Description

technical field [0001] The invention belongs to the technical field of inverter pulse width modulation, and in particular relates to a hysteresis-loop random spread spectrum method in random pulse width modulation selective harmonic elimination of inverters. Background technique [0002] In a traditional sinusoidal pulse width modulation (Sinusoidal Pulse Width Modulation, SPWM) strategy, the switching frequency of the inverter is usually fixed. More high-order harmonics will be generated at the switching frequency and its integer multiples; it is the main cause of electromagnetic vibration and noise of loads such as motors. Although increasing the operating frequency of the inverter can weaken electromagnetic vibration and noise; it is not suitable for applications where the switching frequency must be limited to a lower value, such as a high-power traction drive system. RPWM can distribute the harmonics that were originally concentrated on the switching frequency and its ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/5395H02M1/12
CPCH02M7/5395H02M1/12
Inventor 赫飞沈家北李国华曹冬满杨涵杰
Owner LIAONING TECHNICAL UNIVERSITY
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