Fundamental Research

Air pollution from emissions by various industries is a persistent and major societal problem with serious health implications and a major source of pollution in nature. Transientplasma - electrical discharges generated by high-voltage pulses - is one of the most promising technologies for air purification and is especially effective in removing the most problematic industrial pollutants such as odor, nitrogen-based pollution, hydrocarbons and harmful biological pathogens.

Research and application tests show the potential of transient plasma for air purification in various industries, but what is urgently required for economic and industrial success is a large step in efficiency, robustness, modularity, flexibility and upscaling.

With our research we aim to take this step. In a collaboration between power electronics experts and high-voltage pulsed power and transient plasma experts, we work on extremely high voltage (100kV) and fast (<1 nanosecond rise time) pulses and modular plasma reactor designs.

The research also includes the development of ultrafast, multilevel pulsed GaN (galliumnitride) based switch modules and a new, fast topology to combine the modules flexibly into a wide range of pulse sources.

The reserach will result in a system with the folloding properties:


For efficient plasma generation, the high-voltage pulses need to rise very fast from zero to peak voltage. Here it holds: the faster, the better. Several nanoseconds rise time is acceptable, but sub-nanosecond rise time is preferred.


Existing pulse topologies are often based on spark gap switches, which are powerful but require maintenance and auxiliary systems, are bulky, and have a limited lifetime and pulse repetition rate. To realize robust and compact systems, it is necessary to move to solid-state semiconductor technology instead ofspark gaps.

Flexibility and Modularity

Every air-purification application may require a different plasma in terms of process volume, specific chemical composition, and so forth. Therefore, the technology should be modular and flexible. Modular means that the system is comprised of identical modules that can be easily arranged to suit every air- purification application. Flexible means that the high-voltage pulses must be on-line variable in amplitude, pulse duration and shape. This flexibility (combined with the required fast rise time) can only be achieved with novel solid-state topologies using next-gen wide band gap semiconductor switches.


For large-scale applications, a significant plasma volume needs to be generated. This is currently solved by placing many systems in parallel, but ideally a high-volume is also generated by using a much higher voltage (>100 kV) and a larger reactor, which has not been researched so far.