Course objective

By the end of the course, students should be able to:

• Understand how electrical energy is converted and controlled.
• Understand power semiconductor devices and switching behaviour.
• Analyse common DC-DC, AC-DC and DC-AC converters.
• Understand CCM, DCM and boundary conduction.
• Calculate voltage, current, ripple, losses and efficiency.
• Understand inductors, transformers and magnetic cores.
• Design basic inductors and high-frequency transformers.
• Understand core loss, copper loss, skin effect and proximity effect.
• Select MOSFETs, IGBTs, diodes, inductors, capacitors and transformers.
• Understand gate driving, switching transients and snubbers.
• Simulate converters using LTspice.
• Connect converter design with thermal management and EMC.
• Complete a small power-converter design project.

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MODULE 1 — Introduction to Power Electronics

1.1 What is Power Electronics?

• Definition of power electronics
• Electrical energy conversion
• Power electronics vs conventional electronics
• Why switching is used
• Linear vs switching power conversion
• Typical power-electronics systems

1.2 Applications

• AC/DC power supplies
• DC/DC converters
• Battery chargers
• Solar inverters
• EV powertrains
• Motor drives
• UPS systems
• Industrial power supplies
• Aerospace power systems
• Renewable-energy systems

1.3 Four Basic Conversion Types

AC → DC

• Rectifiers
• Power-factor-correction converters

DC → DC

• Buck
• Boost
• Buck-boost
• Isolated converters

DC → AC

• Inverters

AC → AC

• AC controllers
• Frequency converters

Practical exercise

Identify the power-conversion stages inside:

• Laptop charger
• EV charger
• Solar inverter
• Electric vehicle
• Battery energy-storage system

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MODULE 2 — Electrical Fundamentals for Power Electronics

2.1 Voltage, Current and Power

• Voltage
• Current
• Resistance
• Power
• Energy
• Real and reactive power
• Apparent power

2.2 DC and AC Waveforms

• Sine wave
• Square wave
• PWM waveform
• Triangular waveform
• Ripple voltage
• Ripple current

2.3 RMS and Average Values

• Why RMS matters
• Average current
• Average voltage
• RMS current
• RMS voltage
• Peak current

2.4 Power and Efficiency

• Input power
• Output power
• Power loss
• Efficiency
• Power density

Practical exercises

• Calculate converter efficiency
• Calculate RMS current
• Calculate capacitor ripple current
• Calculate power loss

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MODULE 3 — Power Semiconductor Devices

3.1 Power Diodes

• PN junction basics
• Forward voltage
• Reverse voltage
• Reverse recovery
• Schottky diode
• Silicon carbide diode

3.2 MOSFETs

• MOSFET structure
• Drain, source and gate
• RDS(on)
• Gate charge
• Switching speed
• Conduction loss
• Switching loss
• Body diode

3.3 IGBTs

• IGBT structure
• Switching characteristics
• Conduction losses
• Switching losses
• MOSFET vs IGBT

3.4 SiC and GaN

• Why wide-bandgap devices matter
• SiC MOSFET
• GaN HEMT
• High-frequency operation
• Switching losses
• Gate-drive requirements

3.5 Thyristors

• SCR
• Latching behaviour
• Applications

Practical exercise

Compare datasheets for:

• Silicon MOSFET
• SiC MOSFET
• IGBT
• Schottky diode

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MODULE 4 — Switching Fundamentals

4.1 Ideal Switch

• ON state
• OFF state
• Ideal switching
• Real switching

4.2 PWM

• Duty cycle
• Switching frequency
• PWM generation
• Fixed-frequency PWM
• Variable-frequency switching

4.3 Switching Waveforms

• VDS
• VGS
• Drain current
• Turn-on
• Turn-off

4.4 Switching Losses

• Turn-on loss
• Turn-off loss
• Conduction loss
• Gate-drive loss

4.5 Practical Switching Problems

• Voltage overshoot
• Current overshoot
• Ringing
• Parasitic inductance
• Parasitic capacitance
• dv/dt
• di/dt

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MODULE 5 — Buck Converter

This should be one of the major modules because the buck converter establishes the fundamental concepts used throughout power electronics.

5.1 Buck Converter Topology

• Basic circuit
• Switch
• Diode
• Inductor
• Capacitor
• Load

5.2 Operating Principle

• Switch ON
• Switch OFF
• Inductor charging
• Inductor discharging
• Energy transfer

5.3 Steady-State Analysis

• Output voltage
• Duty cycle
• Inductor current
• Ripple current
• Capacitor ripple voltage

5.4 CCM

• Continuous conduction mode
• Waveforms
• Design equations
• Component selection

5.5 DCM

• Discontinuous conduction mode
• Three operating intervals
• Boundary between CCM and DCM

5.6 Practical Buck Converter

• MOSFET selection
• Diode selection
• Inductor selection
• Capacitor selection
• Switching frequency

5.7 Synchronous Buck

• High-side MOSFET
• Low-side MOSFET
• Dead time
• Body-diode conduction
• Efficiency improvement

Simulation

LTspice: Design a 12 V → 5 V, 5 A buck converter.

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MODULE 6 — Boost Converter

6.1 Basic Boost Topology

• Inductor
• Switch
• Diode
• Capacitor

6.2 Operating Principle

• Energy storage
• Energy transfer
• Switch ON
• Switch OFF

6.3 Design

• Duty cycle
• Inductor ripple
• Output ripple
• Peak current

6.4 CCM and DCM

6.5 Practical Problems

• Diode losses
• MOSFET losses
• Voltage overshoot
• Inductor saturation

6.6 Applications

• Battery systems
• PV systems
• PFC
• LED drivers

Simulation project

Design a 12 V → 24 V boost converter.

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MODULE 7 — Buck-Boost and Other Non-Isolated Converters

7.1 Buck-Boost

• Inverting buck-boost
• Operating principle
• CCM
• DCM

7.2 SEPIC

• Topology
• Operation
• Advantages
• Applications

7.3 Cuk Converter

• Operating principle
• Continuous input current
• Advantages and disadvantages

7.4 Four-Switch Buck-Boost

• Bidirectional power flow
• Battery applications

Practical design

Select the appropriate topology for different voltage-conversion requirements.

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MODULE 8 — Capacitors in Power Electronics

8.1 Why Capacitors Are Important

• Energy storage
• Filtering
• DC-link applications
• Decoupling

8.2 Capacitor Types

• Ceramic
• Aluminium electrolytic
• Polymer
• Film

8.3 ESR and ESL

• Equivalent series resistance
• Equivalent series inductance
• Ripple current

8.4 Capacitor Loss

• Ripple current
• ESR heating
• Lifetime

8.5 DC-Link Capacitors

• DC-link ripple
• Bulk capacitance
• High-frequency bypassing

Practical exercise

Select a DC-link capacitor for a switching converter.

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MODULE 9 — Fundamentals of Magnetics

This is the foundation of the magnetics section. Dedicated power-electronics curricula typically cover magnetic circuits, inductor/transformer modelling, core losses and winding losses.

9.1 Why Magnetics Are Needed

• Energy storage
• Energy transfer
• Filtering
• Isolation
• Voltage conversion

9.2 Magnetic Fields

• Magnetic flux
• Flux density
• Magnetic field strength
• Permeability
• Reluctance

9.3 Magnetic Circuit

• Magnetic path
• Core
• Air gap
• Reluctance
• MMF

9.4 B-H Curve

• Linear region
• Saturation
• Hysteresis
• Remanence
• Coercivity

9.5 Faraday's Law

• Voltage and changing flux
• Flux waveform
• Volt-seconds
• Transformer operation

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MODULE 10 — Inductor Fundamentals

10.1 What Does an Inductor Do?

• Energy storage
• Current smoothing
• Filtering

10.2 Inductor Construction

• Core
• Winding
• Bobbin
• Air gap

10.3 Inductance

• Factors affecting inductance
• Number of turns
• Core material
• Core geometry
• Air gap

10.4 Inductor Current

• Ripple current
• Peak current
• Average current

10.5 Saturation

• What saturation means
• Saturation current
• Loss of inductance
• Excessive current
• Converter failure

10.6 Selecting an Inductor

• Inductance
• RMS current
• Saturation current
• DCR
• Core loss
• Temperature rise

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MODULE 11 — Practical Inductor Design

11.1 Core Selection

• Ferrite
• Powder cores
• Iron powder
• Nanocrystalline materials
• Amorphous materials

11.2 Core Geometry

• EE
• EI
• EFD
• RM
• Toroid
• PQ

11.3 Air Gap

• Why an air gap is used
• Energy storage
• Saturation control

11.4 Number of Turns

• Selecting turns
• Flux density
• Window utilisation

11.5 Wire Selection

• Wire diameter
• Current density
• Temperature rise
• Parallel wires
• Litz wire

11.6 Complete Inductor Design

Example:

Design a 10 µH, 20 A buck-converter inductor.

Students determine:

• Core
• Number of turns
• Air gap
• Wire size
• DCR
• Copper loss
• Core loss
• Temperature rise

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MODULE 12 — Transformer Fundamentals

12.1 Transformer Operation

• Primary
• Secondary
• Flux
• Turns ratio
• Voltage ratio

12.2 Ideal Transformer

12.3 Real Transformer

• Magnetising inductance
• Leakage inductance
• Winding resistance
• Parasitic capacitance

12.4 Transformer Core

• Ferrite
• Core size
• Flux density
• Saturation

12.5 Transformer Reset

• Volt-second balance
• Flux walking
• DC bias

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MODULE 13 — High-Frequency Transformer Design

13.1 Transformer Design Process

• Define input voltage
• Define output voltage
• Power rating
• Switching frequency
• Maximum flux density
• Core selection

13.2 Turns Calculation

13.3 Winding Design

• Primary winding
• Secondary winding
• Interleaving
• Winding arrangement

13.4 Leakage Inductance

• Causes
• Effects
• Voltage spikes
• Reduction techniques

13.5 Parasitic Capacitance

• Primary-to-secondary capacitance
• Common-mode current
• EMI implications

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MODULE 14 — Magnetic Losses

14.1 Core Loss

• Hysteresis loss
• Eddy-current loss
• Frequency dependence
• Flux-density dependence

14.2 Copper Loss

• DC resistance
• RMS current

14.3 Skin Effect

• Why current moves toward the conductor surface
• Frequency dependence
• AC resistance

14.4 Proximity Effect

• Adjacent conductors
• Magnetic fields
• Winding losses

14.5 Litz Wire

• Construction
• Advantages
• Limitations

14.6 Thermal Design

• Core temperature
• Winding temperature
• Temperature rise

Skin and proximity effects are particularly important in high-frequency converters because AC winding losses can become substantially higher than simple DC-resistance calculations suggest.

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MODULE 15 — Isolated DC-DC Converters

15.1 Why Isolation?

• Safety
• Ground separation
• Multiple outputs
• System architecture

15.2 Flyback Converter

• Basic operation
• Transformer as an energy-storage element
• CCM
• DCM
• RCD clamp

15.3 Forward Converter

• Operation
• Transformer reset
• Output filter

15.4 Push-Pull Converter

15.5 Half-Bridge Converter

15.6 Full-Bridge Converter

15.7 Introduction to LLC

• Resonant tank
• Resonance
• Soft switching
• ZVS
• High-frequency operation

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MODULE 16 — Rectifiers and AC-DC Conversion

16.1 Diode Rectifier

• Half-wave
• Full-wave
• Bridge rectifier

16.2 Capacitor-Input Rectifier

• Charging pulses
• Ripple
• Peak current

16.3 Three-Phase Rectifier

• Six-pulse rectifier
• DC output
• Ripple frequency

16.4 Power Factor

• Displacement
• Distortion
• Harmonics

16.5 PFC Introduction

• Why PFC is required
• Boost PFC
• CCM PFC
• Interleaved PFC

MIT's power-electronics curriculum similarly treats rectifiers, power factor, DC/DC converters and magnetics as core foundations before moving into more advanced converter topics.

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MODULE 17 — DC-AC Inverters

17.1 Single-Phase Half-Bridge

17.2 Single-Phase Full-Bridge

17.3 PWM Inverter

• Sinusoidal PWM
• Carrier waveform
• Modulation index

17.4 Dead Time

• Why it is required
• Cross-conduction
• Dead-time distortion

17.5 Three-Phase Inverter

• Six-switch bridge
• Switching states
• Phase voltage
• Line voltage

17.6 Applications

• Motor drives
• Solar inverters
• UPS
• EV traction

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MODULE 18 — Switching Transients, Snubbers & Protection

18.1 Why Switching Creates Ringing

• PCB parasitic inductance
• Device capacitance
• Loop area

18.2 MOSFET Turn-On/Turn-Off

18.3 Voltage Overshoot

18.4 RCD Snubber

18.5 RC Snubber

18.6 TVS Protection

18.7 Gate Resistor

18.8 Active Gate Control

Practical laboratory

Measure:

• VDS
• VGS
• Drain current
• Overshoot
• Ringing

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MODULE 19 — Thermal Management

19.1 Where Does Heat Come From?

• Semiconductor conduction loss
• Switching loss
• Magnetic loss
• Capacitor loss

19.2 Thermal Resistance

• Junction
• Case
• Heatsink
• Ambient

19.3 Heatsinks

19.4 Forced-Air Cooling

19.5 PCB Thermal Design

19.6 Junction Temperature

Practical exercise

Calculate the expected junction temperature of a MOSFET.

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MODULE 20 — Gate Drivers

20.1 Why Gate Drivers Are Required

20.2 Low-Side Gate Drive

20.3 High-Side Gate Drive

20.4 Bootstrap Driver

20.5 Isolated Gate Driver

20.6 Gate Resistance

20.7 Miller Effect

20.8 Shoot-Through

20.9 Dead Time

20.10 SiC/GaN Gate Driving

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MODULE 21 — Feedback & Control Fundamentals

21.1 Open Loop vs Closed Loop

21.2 Voltage Feedback

21.3 Error Amplifier

21.4 PWM Controller

21.5 Voltage-Mode Control

21.6 Current-Mode Control

21.7 Compensation

• Type I
• Type II
• Type III

21.8 Loop Stability

• Gain
• Phase
• Crossover frequency
• Phase margin

21.9 Introduction to Bode Plots

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MODULE 22 — EMI & EMC Fundamentals

This would be particularly valuable as a NextGenBright practical engineering module, because students can connect converter switching behaviour directly to real EMC problems.

22.1 What Is EMI?

• Conducted EMI
• Radiated EMI

22.2 Noise Sources

• dv/dt
• di/dt
• Switching nodes
• Gate-drive loops

22.3 Common-Mode Noise

22.4 Differential-Mode Noise

22.5 Current Return Paths

22.6 PCB Layout

• High-current loops
• Gate-drive loop
• Ground planes
• Power/ground separation

22.7 EMI Filters

• Common-mode choke
• Differential-mode filter
• X capacitor
• Y capacitor

22.8 Practical EMC Debugging

• Near-field probes
• LISN
• Spectrum analyser
• Current probes

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MODULE 23 — Simulation with LTspice

Students learn to simulate:

1. Buck converter
2. Boost converter
3. Buck-boost
4. Flyback
5. Full-bridge inverter
6. Gate driver
7. Snubber
8. LC filter
9. Transformer
10. LLC converter

Simulation skills

• Transient analysis
• AC analysis
• Parameter sweep
• .step
• .meas
• Efficiency calculation
• Waveform measurement
• FFT
• Bode plots

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MODULE 24 — Practical Power Electronics Design

Students complete a complete converter design.

Design flow

Specification → Topology → Switching device → Magnetics → Capacitors → Gate driver → Thermal → PCB → Simulation → Testing

Students learn how engineers actually approach a design rather than simply solving equations.