Micro and Precision Devices


Patent 14020/TUB


This invention provides a generator that converts mechanical energy to electrical energy for use, for example, in electronic door closing systems and energy conversion systems.




A variety of different generators are already known for converting mechanical energy into electrical energy. One form is the so-called transverse flux machines, and a special form is the claw pole generators. Due to their complex design, which is based on the complicated geometry of the flux-carrying parts, these are very complex and expensive to manufacture. Up to now, they have therefore only been used in large quantities in vehicle alternators. Another major disadvantage of previous claw-pole alternators is their high cogging torque.


Technical description


First results A prototype of the generator was built and measured at the TU Berlin. The cogging torque determined in this process is significantly lower than that of other claw pole generators of this size and does not represent any restriction for operation. Further reductions in the cogging torque could certainly be achieved through increased manufacturing accuracy. The effective clamping voltage and the power output at variable speed for different electrical loads were also investigated. As expected, the clamping voltage and power output depend on the selected load. Matching the load to the impedance of the generator is required to achieve the maximum power. The advantage of the claw-pole generator over other designs is its high pole pitch. Necessary voltages are thus already reached at relatively low speeds.




Low cogging torque

Self-sufficient power generation

Simple construction

Cost-effective manufacturing

Can be used as a motor


Possible applications

The generator can be used in the following areas: various sensory applications, energy harvesting systems, consumer electronics, electronic door locking systems and energy conversion systems.


Even though a wide range of solutions already exist, the demand for miniaturized generators that can supply small consumers with energy as autonomously as possible is constantly increasing.


For this purpose, this electrodynamic transducer in claw-pole design with significantly improved operating characteristics was developed, which can be manufactured easily and cost-effectively, as well as miniaturized without any problems. In contrast to known generators, this one has a special design with two magnets magnetized continuously in one direction and two claws arranged offset to each other. In addition, the air gap is always between 2 flux-carrying soft iron components and can thus be adjusted very precisely. By using the two claws, the sum of the magnetic resistances can be kept almost constant, resulting in only an extremely low cogging torque.

Possibilities of cooperation


R&D Cooperation


Patent purchase


Please contact us: ptz7@mfg.tu-berlin.de

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