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The trends in power DC/DC conversion are not only size and weight reduction together with a good efficiency; EMI and mass production are a must as well. In this context, piezoelectric transformers seem to be the ideal solution, since they allow higher switching frequencies (size and weight reduction) while also providing high efficiencies. Additionally, they are not magnetic devices, which facilitates...
This work presents the electromechanical characterization and design of a Piezoelectric Transformer (PT) made on a Silicon-On-Insulator (SOI) structure through a bulk micromachining process exploiting low-frequency flexural-modes. The footprint area of the device is less than 3.5 mm2. The purpose of this work is to show the enhancement obtained with respect to prior state of the art in terms of quality...
This paper describes auxiliary power supply for supplying high-side MOSFET driver using piezoelectric transformer. The proposed circuit consists of the piezoelectric transformer and driving circuit. The circuit allows 100% duty cycle of the high side MOSFET driver. Used piezoelectric transformer works in radial vibration mode. To verify the power supply function the full bridge convertor was used...
Light emitting diode (LED) lights are becoming more popular nowadays due to their advantages such as low cost, design flexibility and environmental friendliness. Piezoelectric transformer (PT) is suitable to drive LED because it reduces its overall size, component count and cost. Advantage of PT is that it has no electromagnetic interference as compared to conventional electromagnetic transformer...
In present study, three longitudinal piezoelectric transformers with size of 18.5×3.5×2 mm3, 26×3×1.5 mm3 and 24×3×2 mm3 are fabricated and tested with a soft PZT (P191) piezoelectric ceramic. The input and the output part vibrate in longitudinal extensional mode. Three configurations of the input and the output voltage are proposed. The electrical measurements results are successfully compared to...
In this paper, the electrical equivalent circuits of the piezoelectric transformer (PT) with heat transfer system (HTS) had been studied. A heat transfer model of the longitudinal vibration PT had been built and an experiment study on the equivalent circuit model of the PT with HTS was proposed. this work provides a useful information for the application of piezoelectric transformer in high-power...
This paper presents a study of the energy transfer of piezoelectric polymer transformers. Several transformer constructions are discussed, evaluated and compared. Analysis and experimental studies for all of the constructions are presented. Results highlighting the parameters of the transformers are provided. A comparison based on frequency, efficiency and geometrical properties is made. As a result,...
A new method is implemented in designing of self-oscillating loop for driving piezoelectric transformers. The implemented method is based on combining both analog and digital control systems. Digitized delay, or digitized phase shift through the self-oscillating loop results in a very precise frequency control and ensures an optimum operation of the piezoelectric transformer in terms of voltage gain...
This paper studies power enhancement of piezoelectric transformers to be used in inductorless, half-bridge, piezoelecteric-based switch mode power supplies for driving a piezo actuator motor system in a high strength magnetic environment for magnetic resonance imaging and computed tomography applications. A new multi element-piezo transformer solution is proposed along with a dual mode piezo transformer,...
This paper describes implementation design and analysis of piezoelectric transformer with pulse dropping technique to produce high voltage. The main contribution is the implementation of pulse dropping mode in inverter switching mechanism to decrease heat of piezoelectric transformer during the high voltage generation. Piezoelectric transformer fed by inverter in this work is dedicated to generate...
This paper presents a methodology to obtain an optimized model of a Radial Piezoelectric Transformer with primary and secondary at same piezoelectric ceramic surface. Three-dimensional simulation by Finite Element Method is utilized as analysis tool. Methodology aim is obtaining an improved accuracy model for low cost Piezoelectric Transformer samples. Finite Element analysis was done in order to...
In this paper an analysis and modeling methodology of piezoelectric transformers is presented. Three-dimensional simulation by Finite Element Method is utilized to obtain the Mason lumped parameter model. The PT has been prototyped and the experimental measurements are compared with the simulations. The results show that the simulation in three-dimensional environment by Finite Element Method reveals...
In recent years LED lighting has been exponentially growing. In daily life the demand for dimmable LED brightness has also increased. This requires that the conventional TRAIC dimmer is compatible with LED driver. This paper presents a low profile LED offline phase-cut dimming ballast, using the serial inductor half bridge (SIHB) converter with piezoelectric transformer (PT), which delivers at output...
This paper deals with the study of the operating frequency variation in piezoelectric plasma generator. The analysis relies on experimental investigations of transformers driven with a digital phase locked loop. The frequency shift attests of simultaneous effects of plasma load and the rise of temperature. Several tests are shown to highlight and distinguish these effects.
A piezoelectric transformer based converter is presented in this paper, which not only is capable of generating high voltages, but also incorporates a bi-directional power stage. Applications of high capacitive loads, such as dielectric electro active polymers (DEAP) [1], often suffer from poor overall system efficiency, as only a small fraction of the supplied electrical energy is transferred to...
In order to control a power supply using piezoelectric transformer, AC current in the transformer needs to be measured. Due to the control strategy it is necessary to measure amplitude, phase angle and zero crossing of this current. In some applications there is common ground between primary and secondary sides of the transformer which is internally implemented inside the transformer. Therefore, current...
A new type of piezoelectric transformer which is based on the stress distribution of the piezoelectric transformer to change the output voltage is presented. In this paper, we verified the feasibility of the principle of the new piezoelectric transformer from the simulation and experiment. The experiment results show a good consistent with the theoretical analysis. The designed piezoelectric transformer...
Inductorless switch mode power supplies based on piezoelectric transformers are used to replace conventional transformers in high power density switch mode power supplies. Even though piezoelectric-based converters exhibit a high degree of nonlinearity, it is desirable to use piezoelectric transformers due to their smaller size, lighter weight, lower electromagnetic interference, higher power density,...
The temperature field of a piezoelectric transformer with heat couple component are analyzed at steady state conditions in this paper. The contour extensional vibration mode of the transformer is determined by impedance simulation analysis and experiment result. Mechanical vibration losses, piezoelectric losses, dielectric losses are considered for a piezoelectric transformer. In order to verify the...
Piezoelectric transformers have been used successfully in DC/AC or DC/DC converter. However, the use of piezoelectric transformers presents a major challenges for power electronic design: the capacitive nature of such devices makes their use delicate as the instantaneous power may be much greater than the average effective power. Due to this challenge, conventional drive circuits, especially inductor,...
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