Triangular carrier slope random distribution pulse width modulation circuit

Abstract

The present invention discloses a triangular carrier slope random distribution pulse width modulation circuit. The circuit comprises a system clock module, a counter module, a Rom module and a random triangular carrier processing module. The system clock module is configured for system clock signals; the counter module is configured to output the count according to the real-time system clock signals; the Rom module is configured to take the count as an address, take out stored random data [Delta]i and transmit the random data [Delta]I to the random triangular carrier processing module; and the random triangular carrier processing module is configured to generate the random triangular carrier according to the random data [Delta]I and output the random triangular carrier to a modulation main circuit. The triangular carrier slope random distribution pulse width modulation circuit can reduce the electromagnetic interference in an electric system from the source and reduce the mechanical vibration and the noise in the condition that the pulse width modulation main circuit topology is not changed so as to provide a new way for effectively solve the electromagnetic interference problem in the electric system and the vibration noise problem at the external portion of the system; and moreover, the vibration and noise reduction does not rely on an additional device so as to reduce the filtering and vibration cost and save the system resource.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and specifically refers to a pulse width modulation circuit with random distribution of triangular carrier slope. Background technique [0002] In power electronics technology, pulse width modulation technology with fixed carrier frequency has been widely used. Based on the equivalent principle of volt-second balance, this technology determines the duty cycle by controlling the on-off of the switching device to modulate different waveforms, but the output voltage has large-amplitude harmonics at the carrier frequency and its multiplier, which is harmful to power The harm of the system is very extensive: for the system, these harmonics are the main source of electromagnetic interference, and the harmonics reduce the electromagnetic compatibility quality of the system, and even affect the normal operation of other devices and equipment in the system in severe cases; for the load , harmon...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the pulse width modulation output voltage with a fixed carrier frequency has a harmonic with a large amplitude at the carrier frequency and its multiplier, and proposes a pulse width modulation circuit with a random distribution of the triangular carrier slope to achieve In order to disperse the harmonic energy; at the same time, the harmonic distortion rate THD of the output voltage remains unchanged

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