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The Magazine

Energy column

The power electronics revolution

Recent developments in materials science and power electronics indicate that wide band-gap semiconductors could power the shift to a renewables-based system.

Three years ago, this column predicted that as digitalization progressed, power electronics would become even more pervasive, with silicon complemented by more efficient semiconductors. Today, those advances are coming even faster and more ferociously than expected, spurred by the burgeoning growth of renewables. Power electronics can be found in our everyday lives. Not just in the spread of personal mobile device chargers or e-car chargers, but also in industrial applications (adjustable motor drives) and mobility. For instance, the rising, whirring sound of an accelerating ICE train is caused by the switching frequency of the semiconductors as pulse patterns are powered up. But they are also found in energy systems as described below.

From Michael Weinhold’s notebook: Power electronics permeate our world today and may play an even greater role as new materials achieve market breakthrough.

What we are seeing is essentially a convergence of several ongoing technological trends with a specific set of market forces and political priorities. One factor in the increasing ubiquity of power electronics is the transition to a renewables-based world, which means that large-scale distributed energy systems (DES) are already a fact of life today. Many of their elements, including wind power, energy storage, and especially photovoltaics (PV), use power electronics for interfacing with the electricity grid. Hence, as these components become more intelligent, pervasive, and compact with increasingly efficient performance, they open up new possibilities that even a few years ago would have seemed fanciful.

What about other predictions regarding new semiconductor materials, for example? Currently, the everyday workhorse is clearly still silicon – a robust, proven, and mature technology used in all power ranges up to high-end HVDC systems. But recently, there have been signs that certain market actors, including established companies as well as promising start-ups and venture capital firms, are betting on silicon to be partially supplemented by a new generation of power semiconductor materials known as wide band-gap semiconductors, such as silicon carbide (SiC) or gallium nitride (GaN).

Semiconductor breakthrough

One breakthrough in this new group of semiconductors came with the successful application of a GaN substrate layer on top of a silicon wafer, which led to the creation of the blue LED light – a discovery for which the inventors won the Nobel Prize in Physics 2014. Although they have a lower power range, these new components, currently still in the commercialization or prototyping phase, can operate at significantly higher switching frequencies with lower switching and conduction losses compared to silicon. These qualities may soon see them used in infrastructures such as e-car motor drives or battery storage inverters, for example.

The rise of power electronics is only beginning.
Michael Weinhold, Chief Technology Officer, Siemens Energy Management Division

These new materials will make power electronics even more attractive, since the technology – if proven reliable and competitive – allows more compact and lightweight inverter design (smaller expenditure for passive filter components) and can operate at higher temperatures.

Convergence of digitalization and power electronics

It should also be noted that inverters contain sensor, communication, and data processing components. I anticipate a fascinating future of all-digital integrated power electronics as the switching element and the intelligence become conjoined in the hardware, creating new possibilities through connectivity.

At the macrolevel, power electronics provide the foundation for achieving political targets such as decarbonization, sustainability, efficiency, or resilience through electrification (e.g., electromobility, heat pumps for cooling and/or heating), through widespread use of DES, and by facilitating the large-scale integration of renewables. For grid operators and consumers alike, changes are coming, but they will also reap the benefits. In a nutshell: The rise of power electronics is only beginning.

Michael Weinhold, CTO Siemens.
Picture credits: Michael Weinhold