Staff

Research Topics:

Causes, propagation paths and interactions of PE/PA currents; modelling of components at the grid side of converter.

The use of power electronic systems is essential for the implementation of climate protection goals and energy saving plans. For a Variable Speed Drive (VSD) System, the most important EMI noise source is the common mode voltage, which in the case of the three phase system is the displacement of the neutral point from the earth potential.

At the grid side, the passive diode rectifiers, also known as Diode-Front-End (DFE), are predominantly used which do not feed any power back into the network. It cannot be avoid that common-mode voltages arise between the grid and the DC link. In a few cases, Active-Front-End rectifiers (AFE) are also used at the grid side. In this case, PWM-frequency common-mode voltages are also generated.

The common-mode voltages generate corresponding common-mode currents that flow in the PE or PA wires. The undesirable effects of the PE/PA currents are:

• Disturbance of communication facilities

• Heating of components in EMC filters

• Fault / false tripping of residual current circuit breakers (RCD) corrosion

Main targets of the Project PEPA:

• Systematisation and description of the causes and propagation paths of the PE / PA currents

• Creation of a modelling environment and a model library with which PE / PA currents up to a frequency of 150 kHz can be calculated and determined

• Comparison of the models through measurements on a reference system

Current research topics:

• Creation of the models of transformer and rectifier up to 150 kHz

• Research of the harmonics behaviour of transformer and rectifier at the grid side

• Comparison of the total power losses of AFE and DFE systems at the grid side

• Analysis the impact of the capacitors and the inductors of the filter on the leakage current

• Design EMC-filters

If you are interested in student work or thesis related to these topics, please write me an email. (Both in German or in English are welcome)