State-of-the-art Piezoelectric Transformer technology

Horsley, E. L.; Foster, M. P.; Stone, D.A.

doi:10.1109/epe.2007.4417637

Cited by 54 publications

(41 citation statements)

References 31 publications

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“…3 illustrates the inductorless half-bridge, consisting of a MOSFET-based half-bridge, the lumped parameter model a half-bridge output rectifier, and an output voltage buffer capacitor, followed by the LED load. Usually, a series inductor is required in the PT-based half-bridge topology [5], [29], in order to achieve ZVS operation of the half-bridge switches and avoid large hard switching losses, in connection to the PT input capacitor C d1 . But through a ZVS optimized PT design, soft switching can be obtained without auxiliary components [3], [14]- [16], [19].…”

Section: Inductorless Half-bridge Topologymentioning

confidence: 99%

“…3) has six modes of operation, divided into the following periods. As mentioned, the switches should be turned ON in between the time periods t 1 − t 2 and t 4 − t 5 , so sufficient dead time should be supplied to the gate signals, in order to utilize the ZVS capability.…”

Section: Inductorless Half-bridge Topologymentioning

confidence: 99%

“…The operation frequency is one of the most critical parts, when utilizing PT-based converters, as the PT resonance frequency is very narrow [3], [5]- [7], [14]- [16], [20]- [22]. Some of the most common control methods are phase lock loop (PLL) [23]- [27] and resonance current control [28], but self-tuned control has also been proposed [29].…”

mentioning

confidence: 99%

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Forward Conduction Mode Controlled Piezoelectric Transformer-Based PFC LED Drive

Roedgaard

Weirich²,

Andersen

2013

IEEE Trans. Power Electron.

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Abstract-Light-emitting diode (LED) illumination is getting more and more common; as LED's performance is rising, the price is falling and is getting competitive. Some of the challenges of ac mains supplied illumination are the requirement of power factor correction (PFC) and the competitiveness of a low priced market. In this paper, a new forward conduction mode (FCM) control method for piezoelectric transformer (PT)-based power converters is proposed. A PT-based LED drive facilitating passive PFC is developed, utilizing and validating the FCM control method. The drive utilizes an inductorless half-bridge topology and for circuit minimization and simplicity it has no load regulation and has a 100-Hz output modulation. The proposed FCM control method ensures that the PT is operated at its optimal operation frequency, which ensures soft-switching operation and a constant gain. As a result a 6.5-W PT-based PFC LED drive has been developed, supplied from 230-V 50-Hz ac mains, achieving a power factor of 0.96. Index Terms-Forward conduction mode (FCD) control, lightemitting diode (LED), power factor correction (PFC), piezoelectric transformer (PT).

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Section: Inductorless Half-bridge Topologymentioning

confidence: 99%

Section: Inductorless Half-bridge Topologymentioning

confidence: 99%

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Forward Conduction Mode Controlled Piezoelectric Transformer-Based PFC LED Drive

Roedgaard

Weirich²,

Andersen

2013

IEEE Trans. Power Electron.

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“…Transmitted energy ratio in PTs cannot exceed 95% due to piezoelectric material losses [1]. PTs are frequency-, load-and temperature-dependent [2,3,4,5]. This fact influences their voltage gain and efficiency.…”

Section: A Pts In Smpsmentioning

confidence: 99%

“…With these approaches, full advantage of PTs could not be achieved and resulted in extra expense, size and effect of EMI in power supplies. Therefore, PTs should be used with inductorless converters in order to have effective reduction of cost and size [3,12,22].…”

Section: B Soft Switching Operation and Constraintsmentioning

confidence: 99%

State-of-the-art piezoelectric transformer-based switch mode power supplies

Ekhtiari

Zhang

Andersen

2014

IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society

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Abstract-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, higher efficiency, and lower cost. Moreover, PTs allow converters to operate in high switching frequencies and by obtaining soft switching condition, switching losses will decrease. This paper discusses power supplies with the trend evaluation of piezoelectric transformer-based converter topologies and control methods. The challenges of piezoelectric transformers regarding soft switching capability and nonlinearity are addressed. This paper can be used as a guideline for choosing a proper topology of piezoelectric-based switch mode power supply and a control method for the required application.

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