PDF (Thesis) - Nottingham eTheses - University of Nottingham

Abstract
Advanced power electronics systems are increasingly being used for AC motor drives,
due to their numerous advantages in terms of performance and flexibility. In a bid to
improve system performance and reduce converter size, higher switching frequencies
are being used; this however pushes switching frequencies harmonics into the MF band
(300 kHz to 3 MHz) and possibly even into the HF band (3 MHz to 30 MHz). Interest
in the research of the electromagnetic interference produced by power electronics and
drives systems has therefore grown over the past few years. To study, reduce or even
possibly eliminate any interaction with other appliances, suitable EMI filters need to
be designed and implemented. Such a need for developing filtering devices requires
accurate HF models for the polluting system to be developed.
The focus of this thesis is on the characterization of a matrix converter induction motor
drive for aerospace application from the point of view of EMI interference and on the
design and implementation of suitable filtering systems. Concerns about Electro Mag-
netic Interferences are particularly justified in the light of the fact that high reliability
is sought after in such applications. Failures of aircrafts’ subsystems could have catas-
trophic consequences, therefore strict standards [1] regulating environmental suscep-
tibility, electromagnetic interference and mechanical testing; amongst others, of such
subsystems, need to be adhered to. The main interest in this work lies in the electro-
magnetic regulations defining the allowable conducted emissions in the frequencies
between 150 kHz and 30 MHz. Parasitic elements play a dominating role in the be-
haviour of the system in this frequency range. The problem is that they are difficult to
identify and model since they are not always directly associable to a specific compo-
nent, therefore every possible path for the currents have to be considered.
The first goal achieved by this work is to characterize the EMI signature of a matrix
converter induction motor drive using common and differential mode measurements
of the converter and motor impedances separately. Based only on these measurements
the project aims to synthesize accurate HF models for the Induction Motor and the Ma-
trix Converter in common and differential mode, without the need of deep level studies
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