Novel frequency modulation method and device using AC feedforward to improve EMI

A frequency modulation and feedforward technology, applied in the field of new frequency modulation methods and devices, can solve the problems of reducing amplitude margin and reducing electromagnetic compatibility, etc.

Inactive Publication Date: 2018-05-15
ZHENGZHOU YUNHAI INFORMATION TECH CO LTD
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  • Application Information

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Problems solved by technology

Its spectrum distribution, as attached image 3 As shown, the frequency of noise harmonics is concentrated, so that the energy superposition of each harmonic at fs is incr

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  • Novel frequency modulation method and device using AC feedforward to improve EMI
  • Novel frequency modulation method and device using AC feedforward to improve EMI
  • Novel frequency modulation method and device using AC feedforward to improve EMI

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Embodiment Construction

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

[0025] On the one hand, the embodiments of the present invention provide a novel frequency modulation method using AC feed-forward to improve EMI, the method comprising:

[0026] Using AC feedforward, divide the AC voltage obtained by sampling into 256 equal parts on average, set the initial frequency at the zero crossing point of the AC voltage as the minimum frequency fmin, and set the maximum frequency fmax at the peak point of the AC voltage; start timing from the zero crossing point, every T / 256 time to change the fre...

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Abstract

The invention provides a novel frequency modulation method and device using AC feedforward to improve EMI. AC feedforward is used. The switching frequency completes a frequency jitter from the zero-crossing point to the peak point of AC voltage in a cycle. The frequency is periodically changed. The frequency at the zero-crossing point of AC voltage is the lowest. The frequency at the peak point ofAC voltage is the highest. The frequency distribution is changed, so that the energy of several or dozens of frequencies with relatively high amplitude is dispersed to new components. According to the invention, the frequency is periodically changed according to the set method; the higher the number of harmonics, the greater the frequency dispersion; the noise harmonic frequency is dispersed, sothat the superimposed energy of harmonics at the switching frequency is reduced; the noise energy is dispersed and reduced; the amplitude margin is guaranteed over the entire frequency band; and the electromagnetic compatibility requirement is met.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a novel frequency modulation method and device for improving EMI by adopting AC feedforward. Background technique [0002] Switching power supply is a kind of power supply that uses modern power electronics technology to control the time ratio of switching tube on and off to maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating. At present, the switching power supply topology is widely used in almost all electronic devices because of its low power consumption, high conversion efficiency, small size, light weight, and wide voltage regulation range. It is an indispensable power supply method for the rapid development of today's electronic information indus...

Claims

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Application Information

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IPC IPC(8): H02M1/44
CPCH02M1/44
Inventor 高鹏飞滕学军
Owner ZHENGZHOU YUNHAI INFORMATION TECH CO LTD
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