System Modeling With Transfer Functions

What is a transfer function? Three examples included.

Tags: Control Theory

Transfer Function Stability - Interesting Facts About Polynomial Form

Quickly determine system stability from the sign of the polynomial coefficients. Numerical analysis not required.

Tags: Control Theory

Control System Block Diagram

A quick refresher on system block diagrams and associated signals.

Tags: Control Theory

Voltage to Current Opamp Converter

Voltage to current transducer circuitry for system instrumentation.

Tags: Instrumentation

Current Mode Control- Where is the Second Pole?

The second pole, typically associated with PI controller, seems to disappear in current mode

Tags: Power Electronics

Lead / Lag Compensators   >> Simulator <<

Introduction to Lead and Lag compensators. Bode plot characteristics and interactive example in the web-based simulator

Tags: Control Theory, Interactive Demo

2nd-order System Dynamics

Natural frequency, damping factor, oscillations, pole locations, time-domain waveforms.

Tags: Control Theory, Interactive Demo

Proportional-Integral (PI) Controller : Theory + Demo   >> Simulator <<

Explore the interactive demo of a PI compensator controlling a motor winding current in both time and frequency domains.

Tags: Control Theory, Interactive Demo

A Quick Look on Three-phase Overmodulation Waveforms

What shape do output voltage waveforms have in non-linear overmodulation region?

Tags: Motor Control

System Dynamics - Time Constants

Three easy ways to estimate system time constants.

Tags: Control Theory

Proportional Controller Implementation

This article focuses on the high-level implementation of the proportional controller with opamps, DSPs, FPGAs, and in Simulink.

Tags: Control Theory

Are FPGAs the Future for the Control of Power Electronics and Motor Drives?

Do you prefer DSPs or FPGAs? Fortunately, there seems to be great future for both.

Tags: Miscellaneous

Textbooks and Journals for Power Electronics and Motor Controls

A list of fundamental resources for general and applied control theory.

Tags: Miscellaneous

Proportional Controller: Theory and Demo   >> Simulator <<

The simplest linear controller explained. Explore the dynamics and steady-state behavior in the web-based simulator.

Tags: Control Theory, Interactive Demo

Bode Plot - Interactive Pole/Zero Placement   >> Interactive <<

Bode plots of low/high-pass filters, PI controller, lead/lag filters and build-your-own. Overlay multiple Bode Plots.

Tags: Control Theory, Interactive Demo

Switching Losses & Simple 3-Dimensional Plotting   >> Interactive <<

This article touches on one of the two loss mechanisms in power electronics: switching loss. Further, a simple table to 3-D plot visualization technique is discussed.

Tags: Power Electronics, Miscellaneous

Capacitor / Resistor Discharge Circuit : Theory + Demo   >> Simulator <<

Let's discharge a charged capacitor with a resistor. Basic circuit, signal diagram, and interactive simulation included.

Tags: Control Theory, Miscellaneous, Interactive Demo

Interactive Website Scope : Documentation

Learn how to use the scope feature used throughout this website.

Tags: Instrumentation, Miscellaneous

Digital Control Loops

Digital control systems are the norm today. Learn a bit about the path from the analog domain to the discrete-time domain.

Tags: Control Theory

Feedback-path Filtering

What is the effect of feedback-path filtering on controller design?

Tags: Control Theory

Final Value Theorem   >> Simulator <<

What is the steady-state output of a transfer function subjected to a step change? There is a simple rule - but does it work in all cases?

Tags: Control Theory, Interactive Demo

IIR to FIR System Conversion   >> Simulator <<

How can one approximate Infinite-Impulse Response systems with Finite-Impulse Response systems?

Tags: Control Theory

Bode Plot Engine Documentation

The Bode Plot Engine is a computing and plotting environment with combined symbolic and numerical inputs.

Tags: Instrumentation, Miscellaneous, Engine

Notes on the Nyquist Stability Criterion

This article by Prof. David Torrey delves into the Nyquist Stability Criterion.

Tags: Control Theory

Supplementary Notes on Circuit Analysis, Pt. 1

This article by Prof. David Torrey focuses on fundamental components.

Tags: Power Electronics

Supplementary Notes on Circuit Analysis, Pt. 2

This article by Prof. David Torrey focuses on analysis techniques.

Tags: Power Electronics

Transformations for Motor Drive Design - Clarke

This article introduces the reader to the ubiquitous 3-phase to 2-phase system transformation.

Tags: Control Theory, Power Electronics & Motor Control

Web-based Simulator Documentation

The Web-based Transfer Function Simulator is a simplistic (yet quite powerful) imitation of commercial products such as Simulink(r) by MathWorks(c) or PLECS(r) by PLEXIM(c). The purpose behind providing the simulator is simple: not everyone has access to Simulink. Alternatively, there might not a free license at the time or simply one would like to explore the design of control systems online on a machine without installed MatLab.

Tags: Instrumentation, Miscellaneous, Engine

Low-Pass Filter Discretization     >>> Interactive Example <<<

Explore the discretization of the most common IIR filter.

Tags: Control Theory, Interactive Demo

S/Z Plane Relationship     >>> Interactive Example <<<

See the effect of pole location in continuous and discrete time domains at the same time.

Tags: Control Theory, Interactive Demo

Fourier Series Demo     >>> Interactive Example <<<

See the relationship between frequency-domain coefficients and time-domain waveform.

Tags: Control Theory, Interactive Demo