Siemens Worldwide

Pictures of the Future



Mr. Sebastian Webel
Mr. Sebastian Webel


Tel: +49 (89) 636-32221

Fax: +49 89 636-35292

Werner-von-Siemens-Straße 1
80333 Munich

Pictures of the Future
The Magazine for Research and Innovation

The Future of Manufacturing

New Software Defined Inverter Could Link the Physical and Digital Worlds

Researcher from Siemens Corporate Technology in Erlangen: Thanks to the use of a new semiconductor material, the era of small custom-made inverters could be soon a thing of the past.

Tapas – the new inverter developed by experts at Siemens Corporate Technology – has innumerable possible uses. It is much more universal in application than previous inverters, features low distortion, and is very dynamic and impressively compact in its design. In order to learn more about the wide range of possible uses, Siemens has now organized a competition in which engineers, scientists, and makers can try out the new inverter and learn what just what it can do.

Robotic arms, audio amplifiers or drones – all of these applications are using so called inverters. Inverters are high-power electronic devices that adapt the frequency of a voltage as desired, in fractions of a second.

Today a wide variety of very specialized small inverters are used for specific application areas. This might soon be a thing of the past, thanks to Tapas, a new universal inverter that was developed by experts at Siemens Corporate Technology.

This innovation of this inverter was primarily made possible by the development of gallium nitride (GaN) – a material that can withstand higher frequencies and temperatures than silicon, the main material currently used in inverters. What’s more, GaN produces less waste heat. “We describe the transition from silicon to GaN as being similar to the switch from vacuum tubes to transistors – it will make completely new applications possible overnight,” says Dominic Buchstaller, who managed the development at Siemens of the new inverter. “The effect will be disruptive.”

Especially Suited for Robotics

Compared to silicon, GaN is still a relatively new semiconductor material and sometimes costs a bit more. All the same, it has good future prospects.  “Due to the material’s outstanding properties, it takes up less space on semiconductor wafers during production. Over the long term, this will push costs below those of silicon,” predicts Buchstaller.

The performance data of the free devices is impressive. Tapas are not only more versatile than traditional inverters – they also cause minimal distortion, are 10 to 50 times more dynamic than conventional systems, and are more compact. This makes them especially well-suited for robots that require great precision at high speeds. However, the areas of application are even more extensive than that. The inverter could, for example, be used in wireless charging, 3D printing or LED and laser technology.

“We describe the transition from silicon to GaN as being similar to the switch from vacuum tubes to transistors."

Open-source for Developers

Gallium nitride is not the only factor that is making innovative flexible inverter technology possible. New software, fast signal processors, and special high-performance filters are also helping to exploit the possibilities of GaN and achieve new levels of flexibility.

Since only a software modification is needed in order to adapt the universal inverter, Siemens refers to the new device as a “software-defined inverter” (SDI). Within certain limits, this completely new class of inverters behaves more like ideal amplifiers than traditional high-power electronic systems. Moreover, because these devices are characterized by a range of possible applications greater than Siemens could possibly exploit by itself, the company has decided to make the technology available to the general public.

One System - many applications: A maker working with ‘Tapas’ at the SDI lab at FAU Erlangen.

“We have produced more than 1,000 Tapas inverters that are currently being shipped free of charge to industrial engineers, university researchers and members of the ‘maker community’,” says Buchstaller. These “makers” are tinkerers who do professional-level work during their free time – building drones, for example.

Four sponsors were among those helping to distribute the Tapas circuit boards to developers free of charge: Texas Instruments, Efficient Power Conversion from California, Würth Elektronik, and Allegro MicroSystems, a sensor manufacturer – these four sponsors supplied the components for Tapas.

Surprising Solutions

But that’s not all Siemens is doing with Tapas. The company wants to exploit the innovation resources of a global community. That’s why it has launched the TAPAS community challenge, in which developers from all over Europe can compete against one another to come up with the best Tapas-related ideas.

Dominic Buchstaller (right) explains Siemens CTO Roland Busch the Tapas development.

That’s also why Tapas is compatible not only with Siemens controls but also with Raspberry PI, a credit-card-size miniature computer that costs only around $35. Millions of these devices have been sold since Raspberry PI was first introduced in 2012. It is widely used by the global maker community and also by researchers and industrial companies. If this miniature computer serves as the “brains” of a device, Tapas is its muscle – the link between the digital and the physical worlds. The right programs enable the system to take on a wide variety of roles.

“All of us are eagerly looking forward to the ideas developers will surprise us with,” says Buchstaller. “For example, we didn’t come up with the idea of using Tapas as an audio amplifier – a student thought of that. But that’s exactly why we created Tapas: to spark people’s imaginations and strike out in new technological directions.”

Hubertus Breuer