What’s the equivalent circuit of piezoelectric transducer

The mechanical energy of piezoelectric ceramics is converted into electrical energy. The electromechanical coupling coefficient is not only related to material parameters, but also related to the working mode of specific piezoelectric materials. For piezoelectric ceramics, its size is also related to the degree of polarization. It only reflects the strength of the coupling between the two types of energy through the piezoelectric effect, and does not represent the conversion efficiency between the two types of energy. The coupling coefficient of the piezoelectric material piezo tubes transducer has different requirements in the different occasions. When making the transducer, it is desirable that the electromechanical coupling coefficient is as large as possible.

The equivalent circuit representation of a PZT materials piezo disc crystal piezoelectric transducer is an electrical network term that expresses the mechanical vibration characteristics of a piezoelectric ceramic, that is, a method of simulating a amount of mechanical quantity into an electrical quantity. The piezoelectric transducer is represented by an equivalent circuit, which has many advantages: first, it can effectively simplify the mechanically complex vibration problem; second, in order to obtain various parameters of the transducer, quantitative analysis or screening Transducer; third, the practical needs, because in practical applications, the piezoelectric transducer is also connected to a specific electronic circuit, the equivalent circuit of the piezoelectric transducer can be better Its peripheral circuits are matched and designed. It can be seen that it is necessary to obtain an equivalent circuit of the piezoelectric transducer.

The resonant characteristic of a Pzt piezoceramic cylinder piezoelectric transducer is that when the signal frequency is changed, it can be found that the current through the piezoelectric ceramic transducer also changes. When the signal frequency is mf, the current through the piezoelectric ceramic transducer is the largest.

According to the knowledge of the AC circuit, the impedance Z of the LC circuit also changes with the frequency. By replacing the piezoelectric ceramic transducer with an LC circuit, it can be found that the resonant frequency of the piezoelectric ring crystal piezoelectric ceramic has the appropriate 1L, 1C, 1R, and 0C. the current through the LC circuit and the impedance of the LC circuit are absolute. The value versus frequency curve is very similar to the relationship between (b) and (c) . Near the series resonance frequency, the impedance characteristics and resonance characteristics of the piezoelectric ceramic transducer are very similar to those of the LC circuit. Therefore, using the electromechanical analogy method and an LC circuit can be used to represent the parameters and characteristics of the piezoelectric ceramic transducer. This LC circuit is the equivalent circuit of the piezoelectric ceramic transducer. For piezoelectric ceramic transducers, near any series resonant frequency,Its electrical behavior can be represented by an LC circuit. In the vicinity of the series resonant frequency of the piezoelectric ceramic transducer, if there is a vibration mode in the value, that is, there is no other parasitic response, it can be considered as a piezoelectric sphere crystal piezoelectric ceramic in a narrow frequency range near the series resonant frequency. The effect parameters 1R, 1C, 1R and 0C are independent of frequency. In practice, by selecting the appropriate size for processing, it is possible to fully isolate the requiring vibration mode from other modes. In addition, considering that in practice, after energization, the piezoelectric ceramic transducer must have energy loss, and this energy loss can be equivalent by a parallel resistance .