Design and Optimization of EMI Filters for Power Electronics Systems
Modern power electronics develop very rapidly. The main direction for development nowadays is increasing power density. This can be achieved by utilizing higher switching frequencies. The last generation of SiC and GaN semiconductors can reach switching frequencies up to several MHz. At the same ti...
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| Format: | Others |
| Language: | en |
| Published: |
2019
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| Online Access: | https://tuprints.ulb.tu-darmstadt.de/8563/2/2019-03-18_Manushyn_Illia.pdf Manushyn, Illia <http://tuprints.ulb.tu-darmstadt.de/view/person/Manushyn=3AIllia=3A=3A.html> (2019): Design and Optimization of EMI Filters for Power Electronics Systems.Darmstadt, Technische Universität, [Ph.D. Thesis] |
| Summary: | Modern power electronics develop very rapidly. The main direction for development nowadays is increasing power density. This can be achieved by utilizing higher switching frequencies. The last generation of SiC and GaN semiconductors can reach switching frequencies up to several MHz. At the same time the number of power electronics devices connected to the power grid has grown significantly during past decades and continues to increase. These two factors result in the high level of power grid pollution with electromagnetic interferences. In order to minimize the emission level, passive electromagnetic interference (EMI) filters are employed.
Within the frame of this thesis, issues related to design and improvement of EMI filters for three-phase power electronic converters are comprehensively studied. Detailed analyses of magnetic materials, filter components, mutual couplings, enhancement methods and filter topologies are presented. Insertion loss of EMI filters is analysed within a system under idealised conditions 50 Ohm reference impedance). Moreover the impact of the reference impedance used for EMI filter characterisation on insertion loss is investigated based on mathematical models.
Behavioural models of EMI filters with different complexity are developed. Diverse simulation approaches are used for profound understanding of the physical processes inherent in EMI filters. Exactness of the behavioural models is proven by measurements of built prototypes. The main insertion loss degradation mechanisms are derived from the developed models. The advantages and disadvantages of models based upon the network theory, S-functions and differential equations with the help of electronic design automation tools are shown.
Existing filter improvement methods are systematized and complemented. Novel improvement possibilities for conventional filters including parasitics compensation methods and mutual coupling minimization are developed. Different combinations of improvement methodologies are applied to reference EMI filters and tested. Multistage filters with enhanced topologies are proposed. Critical comparison of conventional and proposed filter topologies considering power density and costs is carried out. Obtained results demonstrate considerable advantages of enhanced EMI filter topologies over conventional ones.
Three phase power electronics systems are examined from the perspective of electromagnetic compatibility. Analysis of common and differential currents' contribution into the spectrum of a conventional drive system is carried out. EMI filters are tested together with different types of power electronic converters. Effects caused by variation of converter parameters on the emitted spectrum of disturbances are assessed from the EMI filter design point if view. It is determined that essentially all investigated parameters of a power electronics converter and a drive system except DC voltage fluctuation have feasible impact on the EMI spectrum. Thus EMC behaviour of the system can be adjusted by variation of these parameters. Semiconductor speed, motor stray capacitance and concept of protective earthing are determined as the most relevant system parameters influencing EMI filter design. |
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