Views:0 Author:Site Editor Publish Time: 2020-02-12 Origin:Site
Dynamic operating frequency of piezoelectric ceramics
Piezoelectric ceramic chips have been widely used in the scientific research, industry, national defense and other precision positioning and control fields due to their piezoelectric characteristics, electromechanical coupling coefficient and other characteristics. Among them, the dynamic operation of piezoelectric ceramics transducer for a considerable proportion in shock absorption and suppression, precision machining, precision detection and other aspects. When it is consulting types of piezoceramic , customers who need dynamic application usually want to use more frequently. The higher is the better, then, what frequency can Pzt powder piezo ceramic achieve?
How to evaluate the frequency of use of piezoelectric ceramics crystal for specific applications? Let's look at:
(1)working rate limiting system
In order to prolong the service life of piezoelectric ceramics, we suggest that customers use piezoelectric ceramics within the safe power range.
Under the dynamic operation, the piezoelectric ceramics will generate heat due to the friction during the stretching process. The overheated temperature will affect the performance of the piezoelectric ceramics, and even lead to the damage of the piezoelectric ceramics.
(2) System resonance frequency of piezo ceramics crystal
When a certain load is applied to piezoelectric ceramics, the resonance frequency of the piezo electric sensor will be reduced, so it is necessary to calculate the resonance frequency of the system after determining the external mechanical load. The resonance frequency of the system is usually calculated by the formula.
In the process of dynamic operation of piezoelectric ceramics, due to the rapid expansion and contraction of piezoelectric ceramics, dynamic force will be generated. Too much power will cause the piezoelectric ceramics to be pulled in the process of expansion and contraction, which will affect their service life and even directly damage the piezoelectric ceramics.
Therefore, we recommend using encapsulated Pzt material piezoelectric plates with a certain preload for dynamic operation, but the preload is limited, usually about one tenth of the maximum load of piezoelectric ceramics. For dynamic applications with higher frequency, we accept special customized piezoelectric ceramics with larger preload. In principle, the dynamic force should not exceed the preload to ensure that the piezoelectric ceramics are not subject to dynamic force production .It can ensure the reliability and service life of piezoelectric ceramics. Especially when the external load is applied, the dynamic force of piezoelectric crystals will increase greatly with the increasing of the load. It is more necessary to calculate the dynamic force of the system in advance to ensure that the piezoelectric ceramics work within the safe dynamic force range. For example, about piezoelectric ceramics ,the effective mass of the system is 1kg, the working frequency is 1000 Hz, the displacement is 4 μ m, and the dynamic force is about equal to plus or minus 80N.
Piezo ultrasonic transducers are capacitive loads, which need enough current to achieve the required frequency response. For some relatively large-scale piezoelectric ceramics, the electrostatic capacity is relatively large. In order to realize high-frequency vibration, a piezoelectric ceramic driving power supply with sufficient power supply current is needed. The peak current of the piezoelectric ceramic driving power supply introduced by the magnetic core tomorrow is 17a.