LLC (Logical Link Control) resonant wide-voltage-range output high-efficiency power supply with variable resonant frequency

Abstract

The invention provides an LLC (Logical Link Control) resonant wide-voltage-range output high-efficiency power supply with a variable resonant frequency, which is used for adjusting the resonance point of an LLC resonant power supply with widely-adjustable output voltage. According to the technical scheme of the invention, the LLC resonant power supply comprises an input circuit, a first switching tube, a second switching tube, a sampling circuit, an output circuit, N resonant cavities and a control circuit, wherein N is at least 2; the resonance point of each of the N resonant cavities is different from one another; the control circuit is used for selecting a preferred resonant cavity for accessing into a current circuit from the N resonant cavities according to a sampling parameter acquired by the sampling circuit; the resonance point of the preferred resonant cavity is matched with a current working frequency; the control circuit is coupled with the sampling circuit and the N resonant cavities. By implementing the scheme of the invention, the electric energy conversion efficiency of the LLC resonant power supply can be increased greatly.

Description

Technical field [0001] The present invention relates to the technical field of electronic power, in particular to an LLC resonance type wide voltage range output high-efficiency power supply capable of changing the resonance frequency. Background technique [0002] LLC resonant power supply is widely used in almost all electronic equipment fields, such as industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instrumentation, medical equipment, semiconductor cooling and heating, air purifiers , Electronic refrigerators, liquid crystal displays, LED lamps, communication equipment, audio-visual products, security monitoring, LED light bags, computer cases, digital products and instruments and other fields. [0003] At present, the LLC resonant charging power supply used for multiple battery packs in series adjusts the output voltage and the output current by the way that t...

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Problems solved by technology

[0005] However, the LLC resonant power supply with only a single resonant cavity has the problem that the operating frequency greatly deviates from the resonance point when outputting in a wide voltage range: the output voltage adjustment range is relatively narrow, and when the output voltage needs to drop to a relatively low level, it is necessary to greatly increase the LLC resonance. The operating frequency of the circuit, at this time, the operating frequency will be much higher than the resonance point. At this time, the secondary rectifier has already lost the zero current switch (ZCS) condition, and the working mode of the LLC resonant circuit will be transformed into an LC series working mode. , losing the high efficiency advantage of LLC

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