applied electronics engineering


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How to change orientation of matrix elements and dimension of matrix in Matlab

- Saturday, February 25, 2017 No Comments
Matlab has lots of useful inbuilt functions that you can use to change orientation of matrix elements and dimension of matrix in Matlab. Transpose is one of them but there are also other functions. The other often used and useful are the reshape, flip, fliplf, flipud, rot90 and repmat functions. We will here how to use them and how they work.

Before you read this tutorial you may want to read the previous tutorials on vector and matrices in Matlab:
First lets make a base matrix called mat with dimension 3x4, 3 rows and 4 columns. We will use the randi function to create arbitary matrix elements.
There are thus 12 elements in the matrix and so we could have various arrangment of the elements such that we have different size of matrix like 2x6, 6x2, 4x3, 1x12 or 12x1 etc. To change the mat matrix above to one of the possible matrix we can use the reshape function.

Let's say we want to change or reshape the above 3x4 matrix to a 2x6 matrix. We can do that as follows,

Note that when doing reshaping the original matrix, mat in this case, will not change.

Next we show how to flip the matrix mat left to right or up to down. To flip the matrix left to right we use the fliplr function as follows.

And to flip the matrix up and down we use the flipud function as follows.

Another useful matlab function to reorient matrix elements which is the rot90. By applying rot90 to a matrix like mat, the elements gets rotated by 90 degree counter-clockwise. See th
 example below.

 Finally we show two functions that changes the matrix dimensions which are the repmat function and the repelem function. They work as follows. The repmat() function replicates a matrix to create another matrix which contains the specified matrix.

Consider a matrix called intmat(internal matrix) with size 2x2 as follows.

Using repmat(intmat, 3,2) we create another matrix with size 3 by 2 such that each element of the new matrix has element intmat.

Download Analytical Methods in Rotor Dynamics Second Edition PDF free

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 Download Analytical Methods in Rotor Dynamics Second Edition PDF free. The design and construction of rotating machinery operating at supercritical speeds was, in the 1920s, an event of revolutionary importance for the then new branch of dynamics known as rotor dynamics. In the 1960s, another revolution occurred: In less than a decade, imposed by operational and economic needs, an increase in the power of turbomachinery by one order of magnitude took place. Dynamic analysis of complex rotor forms became a necessity, while the importance of approximate methods for dynamic analysis was stressed. Finally, the emergence of fracture mechanics, as a new branch of applied mechanics, provided analytical tools to investigate crack influence on the dynamic behavior of rotors. The scope of this book is based on all these developments. No topics related to the well-known classical problems are included, rather the book deals exclusively with modern high-power turbomachinery.

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Fundamentals of Machine Theory and Mechanisms PDF free download

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Download Fundamentals of Machine Theory and Mechanisms PDF free. This book develops the basic content for an introductory course in Mechanism and Machine Theory. The text is clear and simple, supported by more than 350 figures. More than 60 solved exercises have been included to mark the translation of this book from Spanish into English. Topics treated include:
dynamic analysis of machines; introduction to vibratory behavior; rotor and piston balanced; critical speed for shafts; gears and train gears; synthesis for planar mechanisms; and kinematic and dynamic analysis for robots. The chapters in relation to kinematics and dynamics for planar mechanisms can be studied with the help of WinMecc software, which allows the reader to study in an easy and intuitive way, but exhaustive at the same time. This computer program analyzes planar mechanisms of one-degree of freedom and whatever number of links. The program allows users to build a complex mechanism. They can modify any input data in real time changing values in a numeric way or using the computer mouse to manipulate links and vectors while mechanism is moving and showing the results. This powerful tool does not only show the results in a numeric way by means of tables and diagrams but also in a visual way with scalable vectors and curves.

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High Performance Control of AC Drives with MATLAB/Simulink Models PDF free download

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Download High Performance Control of AC Drives with MATLAB/Simulink Models PDF free. The book is authered by Haitham Abu-Rub, Atif Iqbal, Jaroslaw Guzinski.

This book provides a comprehensive guide to understanding AC machines with exhaustive simulation models to practice control design with matlab. Nearly seventy percent of the electricity generated worldwide is used by electrical motors. Worldwide, huge research efforts are being made to develop commercially viable three- and multi-phase electric and motor drives systems that are economically and technically feasible.

Focusing on the most popular AC machines used in industry – induction machine and permanent magnet synchronous machine – this book illustrates advanced control techniques and topologies in practice and recently deployed. Examples are drawn from important techniques including Vector Control, Direct Torque Control, Nonlinear Control, Predictive Control, multi-phase drives and multilevel inverters.
High Performance Control of AC Drives with MATLAB/Simulink Models
Key features include: systematic coverage of the advanced concepts of AC motor drives with and without output filter; discussion on the modelling, analysis and control of three- and multi-phase AC machine drives, including the recently developed multi-phase-phase drive system and double fed induction machine; description of model predictive control applied to power converters and AC drives, illustrated together with their simulation models; end-of-chapter questions, with answers and PowerPoint slides available on the companion website

This book "High Performance Control of AC Drives with MATLAB/Simulink Models" integrates a diverse range of topics into one useful volume, including most the latest developments. It provides an effective guideline for students and professionals on many vital electric drives aspects. It is an advanced textbook for final year undergraduate and graduate students, and researchers in power electronics, electric drives and motor control. It is also a handy tool for specialists and practicing engineers wanting to develop and verify their own algorithms and techniques.

Chapter 1 Introduction to High Performance Drives (pages 1–17):
Chapter 2 Mathematical and Simulation Models of AC Machines (pages 19–43):
Chapter 3 Pulse Width Modulation of Power Electronic DC?AC Converter (pages 45–138):
Chapter 4 Field Oriented Control of AC Machines (pages 139–170):
Chapter 5 Direct Torque Control of AC Machines (pages 171–254):
Chapter 6 Non-Linear Control of Electrical Machines Using Non?Linear Feedback (pages 255–291):
Chapter 7 Five-Phase Induction Motor Drive System (pages 293–364):
Chapter 8 Sensorless Speed Control of AC Machines (pages 365–399):
Chapter 9 Selected Problems of Induction Motor Drives with Voltage Inverter and Inverter Output Filters (pages 401–477):

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PID and Predictive Control of Electrical Drives and Power Converters Using MATLAB/Simulink PDF free download

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Download PID and Predictive Control of Electrical Drives and Power Converters Using MATLAB/Simulink PDF free. PID and Predictive Control of Electric Drives and Power Supplies Using MATLAB/Simulink examines the classical control system strategies that are widely used in current practice, such as PID control, feed-forward control, and cascade control. The book includes sections on closed-loop performance analysis in frequency domain and time domain. These are presented in a way that helps designers in the selection of controller parameters and validation of the control system.

Electrotechnical Systems: Simulation with Simulink® and SimPowerSystems PDF free download

- Friday, February 24, 2017 No Comments
Download Electrotechnical Systems: Simulation with Simulink® and SimPowerSystems PDF free. Filling a gap in the literature, Electrotechnical Systems: Simulation with Simulink® and SimPowerSystems™ explains how to simulate complicated electrical systems more easily using SimPowerSystems™ blocks. It gives a comprehensive overview of the powerful SimPowerSystems toolbox and demonstrates how it can be used to create and investigate models of both classic and modern electrotechnical systems.

Build from Circuit Elements and Blocks to System Models:
Building from simple to more complex topics, the book helps readers better understand the principles, features, and detailed functions of various electrical systems, such as electrical drives, power electronics, and systems for production and distribution of electrical energy. The text begins by describing the models of the main circuit elements, which are used to create the full system model, and the measuring and control blocks. It then examines models of semiconductor devices used in power electronics as well as models of DC and AC motors. The final chapter discusses the simulation of power production and transmission systems, including hydraulic turbine, steam turbine, wind, and diesel generators. The author also develops models of systems that improve the quality of electrical energy, such as active filters and various types of static compensators.

 Download link:®_and_SimPowerSystems.pdf

Send pulses from Simulink to the Arduino PWM pins

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As you perhaps know you can co-simulate Arduino with Simulink. By connecting various blocks in the simulink such as sine wave, square wave, mathematical operators and so on to arduino hardware blocks such as PWM output blocks or digital output blocks or input blocks we can perform signal analysis, send various kinds of signals to the arduino hardware. We showed earlier how to do Arduino Simulink Digital Input example.

In this arduino simulink tutorial, we wanted to show how to send signal like pulses from Simulink to the Arduino PWM pins. By sending pulses from simulink a LED connected to the Arduino board will blink at the rate specified by the sample time in the pulse generator in the simulink. On the hardware side, we connect a LED to the PWM pin 5. Note that the pin is grounded using 220Ohm resistor. Below is the hardware setup picture.

Now in simulink we use the pulse generator block from the simulink sources library and use the PWM block.

Send pulses from Simulink to the Arduino PWM pins

In this setup, the pin 5 PWM pin on the Arduino board was used. The PWM block is available in the common section or Simulink Support for Arduino Hardware.

Also we have connected a Scope to view the output from the Pulse Generator. The following shows the pulses sent to the Arduino.

Now by connecting the Arduino board to the computer and running simulation you should see the LED blinking on and off. The pulses were sent from simulink to the Arduino.

So in this way you can send pulses from simulink to the Arduino PWM pins. See also other arduino tutorials-

How to find dimension of vectors and matrices in Matlab

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Matlab is a very good programming software when it comes to vector and matrices. Often you need to determine your vector or matrix dimension such as length and size. There are few inbuilt functions that you can use to determine the length and size of vector and matrices.

This is continuing tutorial on vector and matrices in Matlab. In the last tutorials we showed you how to create vectors and matrices in Matlab and how to refer and modify matrix elements in Matlab

How to find dimension of a vector in Matlab

Consider a vector first. To find length of a vector you can use the length() function and to find the size you can use the size() function.Consider a vector vec which has elements from -2 to 1, that is, -2, -1, 0 and 1. This vector has thus 4 elements and since it is a row vector it size is 1x4 which means one row and 4 columns. The following illustrates how to find length and size of the vector vec.

How to find dimension of a matrix in Matlab

Now consider how to find dimension, that is length and size of a matrix in Matlab. For this lets make a matrix mat as follows.

Now what is the length of this matrix? what do you think matlab will return if we try to find its length using the length() function? When length is used in matrix in matlab then matlab will return either the row or column whichever is larger. In this case the row is 3 and column is 2 so Matlab will return number of row 3,

Similarly we can get the size of the matrix using the size() function as follows,

So in this way you can find dimension of vectors and matrices in Matlab.