Power Electronics: DC-DC Converter Design & Control

Introduction to how switching converters modify DC voltage using duty cycle control, low-pass filtering, and high-efficiency switching principles, including basic buck and boost concepts.

Explanation of DC-DC converter basics, including duty cycle, switching behavior, low-pass filtering, efficiency, and how feedback control regulates the output voltage.

Introduction to the first analysis method of switching converters, based on steady-state behavior and preparing for volt-second balance.

Introduction to volt-second balance and steady-state analysis of switching converters using inductor behavior.

Learn how converter start-up leads to steady-state operation and how inductor volt-second balance is used to analyze switching converters.

Learn capacitor amp-second balance and simulate a discrete buck converter power stage in LTspice, including switching behavior and practical loss elements.

Learn how boost converters support low-voltage automotive conditions and use inductor volt-second balance to analyze their ideal steady-state voltage conversion ratio.

Complete the boost converter steady-state analysis using capacitor charge balance, then derive inductor current ripple and output voltage ripple for component selection.

Learn how switching converters can be modeled in steady state using equivalent circuits and the ideal DC transformer model for voltage, current, and efficiency analysis.

Extend the steady-state converter model by adding inductor winding resistance and analyze how copper losses affect boost converter voltage gain and efficiency.

Build the boost converter equivalent circuit model with inductor copper loss and use circuit analysis to calculate output voltage and efficiency.

Learn how a photovoltaic-fed buck converter can be modeled and analyzed using MATLAB and Simulink. This lecture starts from the detailed switching model, defines the PV and converter operating parameters, and then develops the dynamic representation using state-space averaging.

You will examine the converter ON-state and OFF-state equations, understand how duty-cycle averaging is used to obtain a continuous dynamic model, and see how the model can be linearized around a selected operating point for small-signal analysis.

The detailed switching model and the small-signal model are simulated and compared to show how the reduced-order dynamic representation captures the important converter behavior while excluding high-frequency switching ripple.

MATLAB scripts and Simulink models used in this lecture are included in the Resources section so you can reproduce and explore the simulations yourself.

Learn how to design and simulate a closed-loop PID voltage controller for a photovoltaic-fed buck converter using MATLAB and Simulink.

This lecture continues from the small-signal buck-converter model developed in the previous lecture. The photovoltaic operating point and converter dynamics are used to construct the plant transfer function and derive the feedback controller.

You will see how MATLAB is used to calculate the controller parameters and obtain the equivalent PID gains, including the proportional, integral, and derivative terms.

The controller is then implemented in a detailed Simulink model of the PV array and buck converter. Simulation results are used to evaluate PV-link voltage tracking, photovoltaic power, and the corresponding converter duty-cycle response.

All MATLAB scripts and Simulink models used in this lecture are included in the Resources section so you can reproduce the controller design and simulation yourself.

Learn how to design and verify a voltage-mode feedback controller for a Buck converter using the K-factor method.

In this lecture, the converter is first examined from a small-signal control perspective. The PLECS model is used to evaluate the power-stage frequency response and obtain the magnitude and phase information required at the selected crossover frequency. These values are then used in MATLAB to calculate the compensator parameters automatically.

You will see how the design links together:

• small-signal modeling of the Buck converter;

• PLECS frequency-response analysis;

• crossover-frequency and phase-margin selection;

• K-factor based pole-zero placement;

• calculation of the compensator gain;

• calculation of R2R_2, R3R_3, C1C_1, C2C_2, and C3C_3;

• MATLAB Bode-plot verification;

• closed-loop verification using the switching PLECS model.

The lecture resources include the MATLAB controller-design script and the PLECS Buck-converter model, so you can reproduce the complete workflow and experiment with your own parameters.

Resources:
voltage_mode_controller.m
Buck_converter_small_signal_analysis_psp.plecs

In this advanced lecture, you will develop a control-oriented model of a DC–DC Boost converter and connect the analytical derivation with practical simulation.

The lecture starts from the ON and OFF switching states, derives the averaged and small-signal model in continuous conduction mode, and obtains the control-to-output transfer function used for voltage-loop design.

You will then study:

• PWM modulator modeling and LTspice verification

• Type III voltage compensator structure

• K-factor-based controller design

• Pole-zero placement concepts

• MATLAB implementation of the Boost small-signal model

• Influence of PWM delay on the frequency response

• Bode-plot analysis of uncompensated and compensated loops

• Analog and digital controller design

• Discrete controller implementation

• PSIM open-loop and closed-loop Boost converter models

Downloadable resources include the MATLAB controller-design script, PSIM open-loop and analog closed-loop models, LTspice files, and supporting README documentation.

This lecture is intended to connect converter modeling, frequency-domain controller design, and simulation-based verification in one practical workflow.

In this lecture, you will design and verify the voltage-control system of a synchronous Buck converter using analytical calculations and multiple simulation tools.

The lecture begins with the Buck converter operating point, component sizing, and control-oriented model. The uncompensated frequency response is then evaluated and a Type III compensator is designed using the K-factor method.

You will then study:

• Buck converter power-stage design and operating point

• Open-loop transfer-function analysis

• Crossover frequency and phase-margin selection

• K-factor-based Type III compensator design

• Controller pole, zero, and gain calculations

• Mathcad-based engineering calculations

• Analog closed-loop verification in PSIM

• LTspice switching-level verification

• Continuous-time and discrete-time controller concepts

• Simulink modeling of the synchronous Buck converter

• ADC quantization and limits

• Digital control delay

• DPWM quantization and duty-cycle limits

• Load-step and transient-response analysis

The lecture connects analytical controller design with practical switching simulation and digital-control implementation.

Downloadable resources include selected Mathcad calculations, MATLAB files, PSIM models, LTspice models, and Simulink models used in the engineering workflow.

In this lecture, you will study the operation, design, simulation, and practical implementation of buck-boost DC-DC converters.

We begin with the classical inverting buck-boost converter, examining the switch ON and OFF states, inductor energy transfer, duty-cycle relationship, current waveforms, and the reason the output voltage is inverted.

The lecture then develops the main engineering design considerations, including:

• inductor sizing and current ripple;

• peak and RMS inductor current;

• output-capacitor RMS current and voltage ripple;

• capacitor ESR effects;

• MOSFET voltage and current ratings;

• diode voltage, peak-current, and average-current requirements;

• verification of the calculated design using PLECS simulation.

The second part moves from the classical inverting topology to practical non-inverting buck-boost solutions used when a positive regulated output is required. SEPIC, Zeta, and other buck-boost arrangements are introduced and compared.

A practical design workflow is then demonstrated using Texas Instruments LM5155/LM5156 design resources, including the Excel-based SEPIC design calculator and WEBENCH-style component-selection and implementation workflows.

The objective is to connect converter theory with the type of engineering process used in real power-supply development: derive the operating relationships, size the components, verify the switching behavior in simulation, and then use vendor design tools when implementing an integrated controller solution.

At the end of the lecture, we also connect this topic to automotive ECU power architectures, where buck-boost capability can be required to maintain regulated internal supply rails during wide battery-voltage variations.

In this lecture, you will see how buck and boost converter functions are integrated into modern automotive System Basis Chips, or SBCs, and how these devices are used as central power and communication building blocks inside an ECU.

Rather than treating the DC-DC converter as an isolated power stage, we now move to the system level and examine how practical automotive ICs combine:

• Buck DC-DC regulation for MCU and ECU supply rails

• Boost regulation for additional or hold-up supply functions

• Secondary LDO regulators

• CAN and LIN communication interfaces

• Watchdog and reset functions

• Wake-up and fail-safe functions

• Diagnostics, supervision, and protection

• Low-power operating modes

• Hardware and software scalability across ECU platforms

The lecture explains why automotive ECUs may require more than a simple step-down regulator. During low-battery conditions such as cranking, the system may still be required to maintain regulated internal supply rails. This creates a practical use case for architectures that combine buck and boost functionality.

Bring together the complete DC-DC converter engineering workflow in the final assessment.

The exam is designed to test your understanding of converter analysis, component design, modeling, control, stability and engineering interpretation across structured technical problems.

After completing the exam, use the complete worked solutions to check your reasoning, calculations and design decisions, and identify the areas you may want to review.

The downloadable Final Engineering Exam and Complete Solutions will be provided in the Resources section of this lecture.

This lecture outlines the next development steps for the course and shows how the material will continue to expand beyond converter analysis and simulation.

Upcoming updates will progressively connect the existing Buck, Boost, and control-design workflows to more practical engineering implementation topics, including:

• hardware realization of DC-DC converter power stages;

• digital control implementation using embedded controllers and DSP-oriented workflows;

• measurement and validation of switching behavior and closed-loop performance;

• practical power-stage design considerations;

• automotive-oriented DC-DC converter applications and ECU power architectures;

• additional advanced control and implementation examples.

These updates will build on the engineering foundation already developed in the course: converter operating principles, steady-state analysis, state-space averaging, small-signal modeling, frequency-response analysis, controller design, simulation, exercises, and the final engineering assessment.

New material will be added progressively as it is completed and technically verified.