Designing with SiC & GaN devices with Emphasis on EMC & Safety considerations

Transcription

1 Designing with SiC & GaN devices with Emphasis on EMC & Safety considerations Dr. Supratim Basu, Prof. Tore Undeland & Prof. Jorma Kyyrä Seminar Presentation Time: Full day Seminar Presentation Abstract: The ability of WBG devices to switch very fast, have negligible switching losses and also low on-state losses at high voltages greater than 600 V, etc, makes them near an ideal switch. While Practical Power Electronics design has never been something straightforward, realizing converters having high power densities at lowest cost, stringent EMI and safety requirements and high efficiency at both full/light load, makes their design even more challenging. Thus good design practice and in depth technical knowledge of power-electronics design, thermal design, failure modes, designing for immunity to noise, control system design, conservative PCB layout, wiring and grounding issues, etc., is the key to success in designing with SiC & GaN components. This intermediate to advanced level course will begin with a refresh on SiC components followed by an in-depth treatment of various topics like switching speed considerations, EMI generation and management, PCB layout, control loop noise susceptibility, ground loops etc. Lastly the focus of this presentation is to present everything with as many practical engineering examples as possible and thus have a mix of both practice and theoretical explanations and not focus on only theory or physics. Presenting Speakers and Affiliations: Corresponding Presenter Dr. Supratim Basu BOSE RESEARCH PVT. LTD. #1, KVC Complex, 5th Main, R.M.V. 2nd Stage, Bangalore , India Tel.: E- Mail: boseresearch@vsnl.net Prof. Tore. M. Undeland NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY Dept. of Electrical Power Engineering, Trondheim, Norway Tel.: , Mail: Tore.Undeland@elkraft.ntnu.no Non-Corresponding Presenter Prof. Jorma Kyyrä ALTO UNIVERSITY Department of Electrical Engineering and Automation, Helsinki, Finland Tel.: Mail: jorma.kyyra@aalto.fi 1

2 Introduction and Overview Si and WBG-An Introduction. EPE 2018, September 2018, Riga, Tutorial-Part 1 The Physics of WBG semiconductors Why SiC Why GaN Comparison between Si and SiC/GaN The SiC Diode Normally on and Normally off devices The SiC transistor The SiC MOSFET GaN devices Commercial availability today. Overview of Important Power Electronics Components. Components: Capacitors, Resistors, Inductors, transformers Components: Diodes, Zeners Components: Magnetics Understanding & Designing with resistors Understanding & Designing with capacitors Understanding & Designing with magnetic components Leakage inductance & Inter-winding Capacitance Driving inductive components. Understanding WBG Design Considerations Design considerations for WBG switches. Switching speed of WBG devices Parasitic oscillations Inductance-a bane or boon Parasitic oscillations Switching and conduction losses of SiC devices Driving SiC FETS/Transistors optimally SiC Driver Circuits GaN devices GaN Driver Circuits Switching and conduction losses of GaN devices Driving GaN FETS optimally Common causes of WBG Device Failures Thermal Considerations Mounting of SiC & GaN devices Important safety considerations Over temperature protection Over current protection of SiC switches Over voltage protection of SiC components Over current protection of GaN switches Over voltage protection of GaN devices. Practical Design Considerations Circuit design, ringing, grounding issues, etc. with SiC & GaN devices Driver circuit design for SiC & GaN devices Understanding transients, circuit protection & ESD Circuit parasitic elements, ringing and damping with SiC & GaN devices Controlling switching speed of SiC & GaN devices Reducing circuit inductance for switching SiC & GaN devices Passive & regenerative snubber circuits Ferrite Beads Kelvin connections Using ICs Generation of noise, coupling & its management Instabilities caused by noise. 2

3 Tutorial-Part 2 PCB & Safety Considerations, EMC Management, etc. PCB Layout issues. Thermal considerations of SiC & GaN SMD power semiconductors Inductance considerations of SiC & GaN SMD power semiconductors Kelvin connections Shielding and noise guards for sensitive signals Grounding considerations and ground planes Understanding and placing decoupling capacitors Reducing heating of capacitors Need for multiple PTHs Placement of heat generating components Selection of components based on wave or reflow soldering Understanding generation of fields from PCB Identifying tracks with high dv/dt and high di/dt. E field and B field coupling Shortest track length and balancing switching currents considerations Understanding significance of resistance, inductance, mutual capacitive coupling and mutual inductance with other PCB traces as PCB traces are not perfect equi-potential conductors Influence of PCB trace inductance on ringing, voltage spikes, switching loss and associated EMI. Managing switching speed of SiC & GaN devices Good converter design always has low high frequency ringing emissions without the need for a slow switching speed or significant snubber dissipation Internal circuit ground node is never at zero potential causing circulating ground loop currents Minimizing coupling of signals and fields by proper component placement Multi-layer PCBs. Overview of EMI management. Design of Practical Filters. Noise Coupling Modes and paths for SiC & GaN applications Electrostatic & Magnetic coupling Common & Differential Mode Noise Ground plane, grounding and high frequency current paths Electric & Magnetic Field Noise Emissions for SiC & GaN applications Emissions from high dv/dt surfaces and remedies Heat-sinks and common mode currents Heat-sink to device capacitance, Heat-sink shields Influence of high speed switching of SiC & GaN components on Common Mode currents through transformer interwinding capacitances Transformer Shields and Flux Straps di/dt Current loops and radiated magnetic field Radiated Magnetic Fields from Magnetic Circuits How noise current flow can contribute to EMI Relevance of switching speed of SiC & GaN devices on EMI Conductors act as Antennas as they carry noise current Improper earthing or high earth resistance significantly increases EMI Safety Capacitors and Leakage currents A typical EMI filter and how it works Mitigating Radiation coupling to filters Shielding EMI filters and their importance Placement of EMI filters and influence on PCB Board Layout. Safety Considerations. Single fault considerations Creepage/clearence distances Safety Capacitors Residual voltages Insulation SELV RMS voltage considerations. 3

4 EPE 2018, September 2018, Riga, End of Tutorial Presentation Biography of Presenting Speakers and Authors: Supratim Basu received the B.E. degree in electrical and electronics engineering from BIT, Mesra, India, in 1988 and the M.Tech. degree from Indian Institute of Science, Bangalore, India, in 1992 & Ph.D. degree from Chalmers University of Technology, Göteborg, Sweden in He has published many papers, presented many lectures in many universities & industries in Europe & India and presented many Seminars in IEEE & EPE conferences on Power Electronics design. His current research interests are power electronics applications and EMI and has independently developed many converters and inverters. Presently he is managing director at Bose Research Pvt. Ltd, Bangalore, India and heads a research and development team of sixteen power electronics engineers. He also works as an independent power electronics consultant for many companies around the world. Tore M. Undeland (M 86, SM 92, F 00) is Professor of power electronics at the Norwegian University of Science and Technology, Trondheim, Norway. He has been teaching since 1972 and as a Professor since He has authored many publications in the field of power converters, snubbers, and control in power electronics. He is a coauthor of the book Power Electronics: Converters, Applications, and Design (New York: Wiley, 2003). Dr. Undeland was the chairman of the European Power Electronics and Drives Association (EPE) 1997 Conference, Trondheim, and is presently member of EPE. He is a Fellow of IEEE. For six years he is a member of the AdCom, IEEE Power Electronics Society. Prof. Jorma Kyyrä received M.Sc., Lic.Sc. and D.Sc. degrees from Helsinki University of Technology (TKK), Helsinki, Finland, in 1987, 1991, and 1995, respectively. He has worked at the university since 1985 in various positionsassociate Professor of Power Electronics since 1996, Professor of Power Electronics since 1998, Dean of the Faculty of Electronics, Communications and Automation during , Vice President at Aalto during and presently head of the department of electrical engineering and automation at Aalto. His research interest is power electronics at large. Power electronics group at Aalto University has expertise e.g. in power electronics for ac drives, dc-dc converters, modeling of converters, 4

5 filtering of EMI, power factor correction, distributed power systems and hybrid electric vehicles. He has been lecturing a full semester course on EMI, for many years. 5