In the field of embedded applications, power converter specifications are crucial. They must not only be efficient and compact, but also meet strict electromagnetic compatibility (EMC) standards. Understand that these converters may be susceptible to their own interference (autoimmunity), cause or experience disturbances in their environment, primarily from common mode currents.
Even low-power power converters can generate high-frequency electromagnetic emissions, which can interfere with other nearby equipment or even disrupt radio signals.
Traditionally, to meet EMC requirements, we rely on shielding and passive filtering techniques, which add significant weight, volume and cost to the system. Around 20% of these costs and constraints are attributed to passive EMC filters.
We note the arrival of new converters (based on large gap SiC/GaN components) whose switching frequencies approach, or even encroach on, the frequency ranges of EMC standards. In order to counter this problem, a new alternative is emerging: active EMC filters. The latter offer at least similar performance while considerably reducing bulk and weight.
As part of this thesis, we will explore these active CEM filters through different stages. We will start with a state of the art, followed by the estimation of common mode and differential mode noise of switching components. Then, we will simulate and compare the most relevant solutions, whether active or passive. We will also get hands-on by performing electromagnetic compatibility tests on common filters and converters.
Finally, we will design and test a prototype active filter for a specific converter. To successfully complete this thesis, it is necessary to master both analog and digital electronics, as well as electronic simulation software (LTspice, Pspice or PSIM) and printed circuit design tools (Altium). Additionally, knowledge of embedded programming would be a valuable asset.