Basics of Power Electronics

Explain why pwm matters in power electronics, show the wasteful resistor approach, and introduce transistor linear operation with load lines and power dissipation concerns.

Explains pulse width modulation to reduce transistor losses by switching on and off, delivering average load voltage via duty cycle, and highlights efficiency gains over linear operation.

Explore LTSpice validation of linear versus switched operation in a 100 V, 5 ohm load circuit, showing 500 W dissipation in linear mode and ~99% efficiency in switched mode.

This lecture explains rms and average values in power electronics, shows how to compute effective values for different waveforms, and use them to estimate conduction losses, switching losses, and efficiency.

Explore how to compute instantaneous and average power, energy, and RMS values for signals in power electronics, and apply decomposition for complex waveforms to simplify calculations.

Learn to compute rms and average values for periodic signals by decomposing waveforms, applying duty cycle concepts, and handling pulsating, rectified, sinusoidal, and offset waveforms.

Learn to use LTSpice to compute average and rms values for different waveforms, and to determine power in a component by calculating i^2 r or integrating v*i.

Learn to compute instantaneous and average power from voltage and current waveforms, and determine energy per period in power electronics.

Assess the cost feasibility of higher-efficiency converters by calculating energy losses and payback time, comparing 86% vs 96.8% efficiency, and examine switching losses during on transitions.

Install SPICE, build a dc-dc converter, and validate theory with operating point, transient, and ac analyses while exploring sources and parameter variations and adding models or libraries.

Build a first circuit in a SPICE-like tool by placing resistors, ground, and a voltage source, wiring nets, measuring voltage, current, and power, and performing operating point and transient analyses.

Explore two sources and waveforms including pulse, sine, and piecewise linear functions in transient simulations, learn to compute average values and powers, and perform ac analysis to reveal frequency response.

Add a new component to your spice library by locating its spice model online, downloading it from Mouser, and importing it for simulation.

Discover thermal considerations in power electronics, focusing on junction temperature, thermal resistance, and heat flow from junction to ambient, and how heatsinks, grease, and fans manage dissipation.

Analyze how to estimate junction temperature in power electronics by using thermal resistance from junction to case and ambient, decide heat sink needs, and compare natural versus forced cooling scenarios.

Validate a MOSFET thermal model by comparing calculated junction temperatures with model predictions. Show heat sink insertion lowers the junction temperature from about 90–95 C to about 42.7 C.

Explore practical switches, including controlled and passive devices, and learn how conduction and switching losses arise and are calculated for resistive and inductive loads using a triangular approximation.

Compare switching losses for resistive and inductive loads using a free-wheeling diode, with XPRIZE validation, and analyze voltage and current waveforms to estimate on-time, off-time, and peak losses.

Explore how switching and conduction losses are calculated for resistive and inductive loads, using duty cycles and voltages, then design thermal management with heatsinks.

Conduct lab tasks on a chopper circuit to analyze duty cycle and efficiency with a BGT and MOSFET, and design a heat sink to keep MOSFET temperature under 100 degrees.

Power diodes pass current in one direction with a forward voltage drop, provide high blocking voltage, and exhibit reverse leakage and reverse recovery that cause switching losses.

Explore types of power diodes—general purpose, fast recovery, and Schottky barrier diodes—focusing on reverse recovery, forward voltage, leakage, and the rise of wide bandgap devices.

Explains why diodes in series require balancing resistors to equalize voltage under high supply and leakage differences, and how parallel diodes use balancing resistors to balance current and prevent overheating.

Explore bipolar transistors for power electronics, focusing on saturation, cutoff, switching, and the role of driver circuits. Learn how base drive, overdrive factor, and storage time influence efficiency and heat.

Explore enhancement-mode power MOSFETs and their voltage-controlled switching. Understand gate-source voltage, Miller plateau, parasitic capacitances, and the importance of gate drivers for fast, efficient operation.

Analyze MOSFET switching considerations, including driver proximity, input capacitance, and damping resistors to prevent oscillations, reduce switching losses, and ensure safe turn-on and turn-off.