Pulse modulation method and system

Abstract

The invention provides a pulse modulation method and system. The pulse modulation method comprises the steps of receiving voltage signal input; calculating the input angle frequency of the voltage signal; calculating and obtaining the starting time of the next switching period according to the input angle frequency; calculating and obtaining the switching frequency of the next switching period according to the input angle frequency and a set fundamental switching frequency; and when it is judged that the next switching period is coming according to the starting time, generating PWM wave of thecorresponding pulse width according to a set duty ratio and the obtained switching frequency of the next switching period through calculation. By virtue of the pulse modulation method, the switchingfrequency of the next switching period can be intelligently adjusted according to the current actually-input voltage signal; in addition, the higher the voltage is, the lower the switching frequency becomes, so that switching loss can be lowered; the switching frequency takes the basic switching frequency as the reference value, so that high frequency requirement can be satisfied; and the switching frequency is changed within a certain range, so that power spectrum can be in broadband distribution, thereby reducing noise and electromagnetic interference.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a pulse modulation method and system applied to switching power supplies. Background technique [0002] Due to the many advantages of switching power supply in terms of quality, volume, energy density and efficiency, it has been widely used in many fields such as industrial production and household appliances. [0003] The most important feature of switching power supply is high frequency. By changing the circuit structure through high-frequency switching of switching elements (such as IGBT and MOSFET), it can effectively reduce the volume of inductance and capacitance, thereby achieving miniaturization. At present, the most widely used pulse width modulation technology (PWM) has a fixed switching frequency. The electromagnetic interference in the switching power supply will pollute the power grid and affect the normal operation of nearby electronic equipment, and the freq...

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Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a pulse modulation method and system for solving the problem in the prior art that the frequency of the switching power supply cannot be intelligently adjusted according to the actual input voltage

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