Skip to main content

Electrodynamic Transducer

Ref-Nr: TA-14020/TUB


Novel claw pole generator for converting mechanical into electrical energy. It has a comparably low cogging torque and can thus expand the possible applications and uses. The claws are arranged offset from one another, whereby two pairs of claws arise, which are also offset from one another. Thereby the rotation of the shaft leads to closing of one pair of claws and opening of the other pair and vice versa.


Kinetic energy is one of the most readily available energy sources for energy harvesting devices. However, rotating machines only rarely applied in such applications as only a few miniaturized generators are available.

It is thus a growing demand for small generator systems with high efficiency for energy harvesting purposes. Typical applications are miniaturized energy sources with a huge lifetime for autonomous electronic devices, such as portable energy sources for emergency systems, wireless electronic
door locks or portable medical devices.

It is therefore an aim of the present technology to provide a novel topology for a claw-pole generator, having an extremely compact design and high conversion efficiency.

Bilder & Videos


A lot of different generators for the conversion of mechanical into electrical energy are already known to the state of the art, for instance the so called transverse flux machines, especially in the form of claw pole generators. But the production of claw pole generators is currently still time-consuming and quite expensive, due to their complex structure, which is caused by the complicated geometry of the flux leading elements. Thus, larger quantities of them are currently only used in alternators for cars. Another huge disadvantage of such transducers is their high detent torque. Even though there are already various solutions, we experience a constant increase of the demand for miniaturized electrodynamic transducers that supply energy also for small scale consumers – preferably in a self-sufficient manner.


To meet the above mentioned requirements, we provide an electro-dynamic transducer, constructed as claw pole generator with significantly improved operational characteristics that can be produced easily and cost-efficiently and can be miniaturized without big effort. In contrast to already known generators, the one developed by

scientists from the TU Berlin provides a special construction with two consistent magnets, that are axially magnetized in one direction, and with two claws that are arranged offset in relation to each other. In addition, the air gap is always between two flux-leading soft iron components and therefore exactly adjustable. Due to the usage of two claws it is possible to keep the sum of the magnetic resistance nearly constant, resulting in only very low detent torque.


First results

A prototype of the generator has already been built and analyzed at the TU Berlin. The determined torque moment is not yet zero, but significantly lower than that of other claw pole generators of this size. But this does not influence its operational behavior in any way. A greater reduction of the torque detent could probably be achieved once the manufacturing accuracy is enhanced. In addition, the effective terminal voltage was examined for different levels of electrical charging, as well as the output at different rotational speeds. This way it could be that output and terminal voltage correspond on the chosen charging as it had already been expected in advance. To achieve the maximal possible performance, it is necessary to adapt the load of the generator to its impedance.


  • Low torque detent
  • Autarkic energy harvesting
  • Simple construction
  • Cost-efficient manufacturing
  • Usable as engine


The generator can be used in the following fields: various sensoric applications, energy harvesting systems, consumer electronics, electronic door locking systems and energy converting systems.


Chances for Collaboration:

  • R&D Cooperation
  • Patent Purchase
  • Licensing

Technische Universität Berlin

Jeanne Trommer
+49 30 314 24472
Fraunhoferstr. 33-36
10587 Berlin




  • DE erteilt
  • EP anhängig
  • US anhängig
  • CN anhängig


autarkic energy harvesting, claw pole generator, converter, electrical machine, electrics, Generator, miniaturization, pole machine

Angebot Anbieter-Website

Kontakt | Geschäftsstelle

TransferAllianz e. V.
Christiane Bach-Kaienburg

c/o PROvendis GmbH
Schloßstr. 11-15
D-45468 Mülheim an der Ruhr