Power enhancement of piezoelectric transformers by adding thermal pad

Abstract

It is well known that power density of piezoelectric transformers is limited by mechanical stress. The power density of piezoelectric transformers calculated by the stress boundary can reach 330 W/cmP 3 P.However, no piezoelectric transformer has ever reached such a high power density in practice. The power density of the piezoelectric transformer is limited to 33 W/cmP 3 Ptypically.This fact implies that there is another physical limitation in piezoelectric transformer. In fact, it is also known that piezoelectric material is constrained by vibration velocity. Once the vibration velocity is too large, the piezoelectric transformer generates heat until it cracks. To explain the instability of piezoelectric transformer, we will first model the relationship between vibration velocity and resulting heat by a physical feedback loop. It will be shown that the vibration velocity as well as the heat generation determines the loop gain. A large vibration velocity and heat may cause the feedback loop to enter into an unstable state. Therefore, to enhance the power capacity of piezoelectric transformer, the heat needs to be dissipated. In this paper, we used commercial thermal pads on the surface of the piezoelectric transformer to dissipate the heat. The mechanical current of piezoelectric transformers can move from 0.382A/2W to 0.972A/9W at a temperature of 55°C experimentally. It implies that the power capacity possibly increases 3 times in the piezoelectric material. Moreover, piezoelectric transformers that are well suited in applications of high voltage/low current becomes also well suited for low voltage/high current power supplies that are widely spread. This technique not only increases the power capacity of the piezoelectric transformer but also allows it to be used in enlarged practical applications. In this paper, the theoretical modeling will be detailed and verified by experiments.

Providing of Rod Piezoceramic Electroacoustic Transducers Thermal Mode Operation

“…Нагрівання ПЕП призводить до таких негативних наслідків -деполяризація та старіння п'єзокераміки, зміна робочої частоти та частоти резонансу, зміна електричного імпедансу та порушення умов узгодження з генератором, обмеження щодо тривалості роботи та режиму роботи [1,2,[8][9][10][11][12][13][14], (Патент РФ № 2304947). Перегрів перетворювача може призвести до виходу з ладу окремих компонентів, або й цілого пристрою.…”

A comparison of 1D analytical model and 3D Finite Element Analysis with experiments for a Rosen-type piezoelectric transformer

“…100 W/cm 3 ) whose heating must be minimised in order to preserve it from ageing (due to depoling). Thermal analysis could be an additional contribution to the model [25].…”

Study of the influence of the housing on the cooling efficiency of the piezoceramic electroacoustic Langevin-type transducer

“…In some housings, it is justified to use more temperature-resistant materialsa piezoceramic composite [10], materials with a high operating temperature. So, in [21], an additional layer of aluminum and a graphite tape is used as an additional heat-absorbing element. To cool the rod transducer, heat-conducting layers of a larger size are used [18,22].…”