Devices, Magnetics, and Thermal Management
This intensive course offers an in-depth technical examination of core power semiconductor devices and the thermal management techniques required for efficient power electronic systems. Beginning with a detailed review of semiconductor physics, the curriculum analyzes the structure, operation, and performance limits of diodes (standard, Schottky, fast-recovery), thyristors (SCR, GTO), power MOSFETs, IGBTs, and JFET-based devices. A significant focus is placed on the superior characteristics of wide bandgap materials like SiC and GaN. Practical topics include calculating switching losses, designing snubber circuits for device protection, and mastering heat-sink selection and thermal resistance modeling to ensure reliable, high power-density operation.
Textbooks
Power Electronics: Converters, Applications, and Design
Ned Mohan, Tore M. Undeland, William P. Robbins · Wiley
Modules
Description: This module serves as a detailed review of the fundamental principles of semiconductor physics, which are crucial for understanding all modern power devices. It covers core concepts like charge carrier generation and recombination, mobility, resistivity, and the behavior of P-N junctions in equilibrium and under bias. This review establishes the theoretical foundation for the rest of the course.
Description: This lecture focuses on the characteristics and operation of various power diodes used in power electronics, including standard, fast-recovery, and Schottky diodes. It analyzes key performance metrics such as Forward Voltage Drop VF, reverse recovery characteristics trr and Qrr, and the design of the drift region to achieve high blocking voltage.
Description: This module introduces the thyristor (silicon-controlled rectifier or SCR), a four-layer, three-junction device primarily used for high-power, low-speed control applications. The lecture explains the two-transistor model of the SCR, its latching behavior, and its characteristic I-V curve, including the necessary conditions for turn-on (gating) and turn-off (commutation).
Description: This video focuses on the gate turn-off (GTO) thyristor, a significant advancement over the standard SCR because it can be turned off by a negative gate current pulse. The module details the GTO's structure, the mechanism of gate-assisted turn-off, and the complexity of the gate-drive circuits required for its high-current switching capabilities.
Description: This lecture explores JFET (junction field-effect transistor) based devices in power electronics, including the normally-on and normally-off configurations. It discusses the physical structure of the vertical JFET and its characteristics such as excellent linearity and high-frequency operation, particularly in the context of wide bandgap materials.
Description: This comprehensive module covers the structure, operation, and characteristics of power MOSFETs. It analyzes the concept of ON-resistance Ron and its components, and details the switching characteristics controlled by the intrinsic gate capacitances Ciss, Coss, and Crss, which dictate the device's high-speed performance.
Description: This video is dedicated to the insulated-gate bipolar transistor (IGBT), a hybrid device combining the high input impedance of a MOSFET with the low conduction loss of a bipolar junction transistor (BJT). It explains the mechanism of conductivity modulation in the drift region and the trade-off between low forward voltage drop and the slower tail current during turn-off.
Description: A critical topic for modern power systems, this module provides an overview of wide bandgap semiconductors, focusing on silicon carbide (SiC) and gallium nitride (GaN). It details their superior material properties—higher breakdown field, faster switching speed, and better thermal conductivity—and how these translate into smaller, more efficient power converters.
Description: This module explains the necessity and design of snubber circuits, which are used to protect power semiconductor devices from high voltage and current stresses during switching. It covers the operation of both turn-on and turn-off snubbers such as the RCD snubber and the process for selecting component values to absorb transient energy and ensure reliable operation.
Description: This lecture focuses on thermal management in power electronics, specifically the design and selection of heat sinks. It introduces concepts like thermal resistance (junction-to-case, case-to-sink, sink-to-ambient), and methods for calculating required heat-sink dimensions to maintain the device junction temperature below its maximum limit.
Description: This video focuses on the passive components of power converters, specifically the design of magnetic components like inductors and transformers. It covers the fundamentals of core materials, the B-H loop, and the process for selecting the appropriate core size and number of turns based on power requirements and saturation limits.
Description: Building on the previous module, this lecture continues the practical design of magnetic devices. It provides detailed considerations for minimizing losses, including winding losses such as skin and proximity effects and core losses. The module focuses on optimizing magnetics geometry for high-frequency operation and maximum energy storage.