An introduction to switched-mode dc-dc converters. The first part of the course treats basic circuit operation, including steady-state converter modeling and analysis, switch realization, discontinuous conduction mode, and transformer-isolated converters. Next, converter control systems are covered, including ac modeling of converters using averaged methods, small-signal transfer functions, and classical feedback loop design. Finally, magnetics design for switched-mode applications is discussed, including: basic magnetics, the skin and proximity effects, inductor design, transformer design.

1. Introduction

• Introduction to Power Processing
• Several Applications of Power Electronics
• Elements of Power Electronics

I. Converters in Equilibrium

2. Principles of Steady State Converter Analysis

• Inductor Volt-Second Balance, Capacitor Charge Balance, and the Small-Ripple Approximation
• Boost Converter Example
• Cuk Converter Example
• Estimating the Output Voltage Ripple in Converters Containing Two-Pole Low-Pass Filters

3. Steady-State Equivalent Circuit Modeling, Losses, and Efficiency

• The DC Transformer Model
• Inclusion of Inductor Copper Loss
• Construction of Equivalent Circuit Model
• Example: Inclusion of Semiconductor Conduction Losses in the Boost Converter Model

4. Switch Realization

• Switch Applications
• Single-Quadrant Switches
• Current-Bidirectional Two-Quadrant Switches
• Voltage-Bidirectional Two-Quadrant Switches
• Four-Quadrant Switches
• Synchronous Rectifiers
• A Brief Survey of Power Semiconductor Devices
• Power Diodes
• Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
• Bipolar Junction Transistor (BJT)
• Insulated Gate Bipolar Transistor (IGBT)
• Thyristors (SCR, GTO, MCT)
• Switching Loss
• Transistor Switching with Clamped Inductive Load
• Diode Recovered Charge
• Device Capacitances, and Leakage, Package, and Stray Inductances
• Efficiency vs. Switching Frequency

5. Discontinuous Conduction Mode

• Origin of the Discontinuous Conduction Mode, and Mode Boundary
• Analysis of the Conversion Ratio M(D,K)
• Boost Converter Example

6. Converter Circuits

• Circuit Manipulations
• Inversion of Source and Load
• Cascade Connection of Converters
• Rotation of Three-Terminal Cell
• Differential Connection of the Load
• A Short List of Converters
• Transformer Isolation
• Full-Bridge and Half-Bridge Isolated Buck Converters
• Forward Converter
• Push-Pull Isolated Buck Converter
• Fly back Converter
• Boost-Derived Isolated Converters
• Isolated Versions of the SEPIC and the Cuk Converter
• Converter Evaluation and Design
• Switch Stress and Utilization
• Design Using Computer Spreadsheet

II. Converter Dynamics and Control

7. AC Equivalent Circuit Modeling

• Introduction
• The Basic AC Modeling Approach
• Results for Several Basic Converters
• Example: A Non ideal Fly back Converter
• State-Space Averaging
• The Canonical Circuit Model
• Modeling the Pulse-Width Modulator

8. Converter Transfer Functions

• Review of Bode Plots
• Single pole/zero/RHP zero Responses
• Frequency Inversion
• Combinations
• Quadratic Pole Response: Resonance
• The Low-Q Approximation
• Approximate Roots of an Arbitrary-Degree Polynomial
• Analysis of Converter Transfer Functions
• Example: Transfer Functions of the Buck-Boost Converter
• Transfer Functions of Some Basic CCM Converters
• Physical Origins of the RHP Zero in Converters
• Graphical Construction of Impedances and Transfer Functions
• Series Impedances: Addition of Asymptotes
• Series Resonant Circuit Example
• Parallel Impedances: Inverse Addition of Asymptotes
• Parallel Resonant Circuit Example
• Voltage Divider Transfer Functions: Division of Asymptotes
• Graphical Construction of Converter Transfer Functions
• Measurement of AC Transfer Functions and Impedances

9. Controller Design

• Introduction
• Effect of Negative Feedback on the Network Transfer Functions
• Feedback Reduces the Transfer Functions from Disturbances to the Output
• Feedback Causes the Transfer Function from the Reference Input to the Output to be Insensitive to Variations in the Gains in the Forward Path of the Loop
• Construction of the Important Quantities 1/(1 + T ) and T/(1 + T ) and the Closed-Loop Transfer Functions
• Stability
• The Phase Margin Test
• The Relationship Between Phase Margin and Closed-Loop Damping Factor
• Transient Response vs. Damping Factor
• Regulator Design
• Lead (PD) Compensator
• Lag (PI ) Compensator
• Combined (PID) Compensator
• Design Example
• Measurement of Loop Gains
• Voltage Injection
• Current Injection
• Measurement of Unstable Systems

III. Modern Power Electronics

10. Power Factor Correction

• Introduction to power factor correction
• Single phase circuit topologies
• Design examples

11. Resonant Converter

• Introduction to Resonant Converter
• Analysis of full bridge dc to dc converter
• Three traditional resonant topologies
• LLC resonant converter
• Operation of LLC resonant converter
• Power stage parameter design of LLC resonant converter
• Extension of LLC resonant topology
• High frequency operation
• Design examples

12. Multi Level inverter

• Introduction to Resonant Converter
• Analysis of various multilevel inverter topologies
• CC multilevel inverter
• DC multi level inverter
• Cascaded multi level inverter
• PWM methods

IV. Magnetics

13. Basic Magnetics Theory

• Review of Basic Magnetics
• Transformer Modeling
• Loss Mechanisms in Magnetic Devices
• Core Loss
• Low-Frequency Copper Loss
• Eddy Currents in Winding Conductors
• Introduction to the Skin and Proximity Effects
• Leakage Flux in Windings
• Foil Windings and Layers
• Power Loss in a Layer
• Example: Power Loss in a Transformer Winding
• Interleaving the Windings
• PWM Waveform Harmonics
• Several Types of Magnetic Devices, Their B-H Loops, and Core vs. Copper Loss

14. Inductor Design

• Filter Inductor Design Constraints
• The Core Geometrical Constant Kg
• A Step-by-Step Procedure
• Multiple-Winding Magnetics Design via the Kg Method
• Window Area Allocation
• Coupled Inductor Design Constraints
• Design Procedure
• Example: Coupled Inductor for a Two-Output Forward Converter
• Example: CCM Fly back Transformer

15. Transformer Design

• Transformer Design: Basic Constraints
• Optimum Flux Density
• A Step-by-Step Transformer Design Procedure
• Example 1: Single-Output Isolated Cuk Converter
• Example 2: Multiple-Output Full-Bridge Buck Converter
• AC Inductor Design