LED constant current control circuit and harmonic distortion optimization method of flyback conversion topology

Abstract

The invention provides an LED constant current control circuit of a flyback conversion topology architecture and a harmonic distortion optimization method. The circuit comprises a voltage input module, a transformer, an output module, a power switch tube that regulates an output current, a phase delay module which compares a feedback voltage of the output module and a reference voltage to obtain acompensation voltage and carries out phase delay on the feedback voltage such that an input average current phase follows an input voltage phase, and a switch control module that controls the turn-onand turn-off of the power switch tube. By the phase delay module, the phase shift of the compensation voltage is adjusted such that the compensation voltage is in phase with an input voltage. At thesame time, the compensation voltage is positively correlated with the input voltage, the product of a duty cycle of the power switch tube and a turn-on time is a constant, the input average current phase follows the input voltage phase, and harmonic distortion is optimized. The method has the advantages of a simple circuit structure, low cost and high reliability.

Description

technical field [0001] The invention relates to the field of circuit design, in particular to an LED constant current control circuit of a flyback conversion topology structure and a harmonic distortion optimization method. Background technique [0002] In current power electronic systems, harmonics are a type of distortion of the normal current waveform, usually caused by nonlinear loads. Switching Mode Power Supply (SMPS), copiers, computers, printers, fax machines, battery chargers, and Uninterruptible Power Supply (UPS) are all non-linear loads. These non-linear loads generate short, high-amplitude pulses of current that cause severe distortion of the current and voltage waveforms, known as harmonic distortion. This distortion propagates back to the power system, which will affect other devices connected to the same power supply, pollute the entire power system, and even cause communication errors, overheating, and hardware damage. [0003] In the current power managem...

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Problems solved by technology

[0009] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an LED constant current control circuit and a harmonic distortion optimization method of a flyback conversion topology, which are used to solve the problems of the LED flyback conversion topology in the prior art. The constant current control circuit has problems such as high harmonic distortion, complex circuit structure, high cost, and poor reliability

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