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PARTLY DIGITAL (ONLY FOR INVITEES) PhD Defence Cees Keyer | From the thyratron to a mess - A survey on modern power electronics from a power quality view

From the thyratron to a mess - A survey on modern power electronics from a power quality view

Due to the COVID-19 crisis the PhD defence of Cees Keyer will take place partly online.

The PhD defence can be followed by a live stream.

Cees Keyer is a PhD student in the research group Power Electronics (PE). His supervisor is prof.dr.ir. F.B.J. Leferink from the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS).

After the introduction of power control for rotating electric machines with gas filled thyratrons and mercury rectifiers in the mid 1920s power quality was not a problem. After WWII and the invention of the semiconducting; transistor, diode and thyristor, it was still no big issue. Most grid connected equipment were linear devices such as rotating machines, incandescent lighting and heating.

The introduction of the, relatively slow, triac for lighting intensity control and the increasing usage of VHF radio did not cause any issues with power quality. But with the increasing usage of high di/dt  switched mode power supplies and the increasing use of wireless connections, power quality has become a growing issue. Almost every domestic appliance nowadays has a switched mode power supply incorporated in the device. Even alternative energy sources such as Photovoltaic systems and wind turbines use high di/dt inverters.

The inherent asymmetry of appliance and mains cables make these cables effective radiators, for conducted emissions and because of the lack of standards for 2 kHz ↔ 150 kHz, there is an increasing problem of interference between power quality and wireless communications. These problematic currents are even causing faulty meter readings in modern static energy meters. This thesis contributes to the understanding of power quality problems in several areas of renewable energy sources and modern lighting.