Resonant frequency tracking circuit of piezoelectric ceramic transformer

Abstract

The invention discloses a resonant frequency tracking circuit of a piezoelectric ceramic transformer. The resonant frequency tracking circuit comprises piezoelectric ceramics, a current switch, a sampling circuit and a phase-locked loop circuit. The piezoelectric ceramics is connected with one end of a resonance inductor, the current switch is connected with the other end of the resonance inductor and is used for converting direct-current voltage input by a power supply into high-frequency pulse current, the sampling circuit is used for sampling input signals or output signals by the piezoelectric ceramics, the phase-locked loop circuit is connected with an output end of the sampling circuit and is used for correcting the sampled signals and outputting the corrected signals as feedback signals to the current switch to control pulse current frequency output by the current switch. The problem that transmission efficiency is lowered since resonant frequency of the piezoelectric ceramic transformer changes along with operation temperature and output load is eliminated and phase of drive frequency can be locked between 105 degrees to 110 degrees by the resonant frequency tracking circuit of the piezoelectric ceramic transformer, and the piezoelectric ceramic transformer is protected from being damaged.

Description

technical field [0001] The invention relates to a piezoelectric ceramic transformer resonant frequency compensation circuit, in particular to a piezoelectric ceramic transformer resonant frequency tracking circuit. Background technique [0002] Piezoelectric ceramic transformers use the piezoelectric effect of piezoelectric ceramics to realize the conversion of electrical energy. Piezoelectric ceramic transformers have the advantages of small size, large transmission power, and high efficiency. Piezoelectric ceramic transformers have the following characteristics: when the temperature rises, the natural resonant frequency rises; when the load increases, the natural resonant frequency rises. The best working state of the piezoelectric ceramic transformer must ensure that the driving frequency is equal to the natural resonance frequency of the piezoelectric ceramic on the one hand, and on the other hand, the phase shift angle must be between 105 and 110 degrees. In order to e...

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Problems solved by technology

[0005] The object of the present invention is to provide a piezoelectric ceramic transformer resonant frequency tracking circuit, which is used to solve the problem that the inherent resonance frequency of the existing piezoelectric ceramic transformer increases due to the temperature rise during the working process, and further causes the piezoelectric ceramic transformer to The problem of the transmission power and efficiency reduction of the transformer

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