BRUSHLESS DC MOTORS
NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA
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BRUSHLESS DC MOTOR
SIMULINK SIMULATOR
Usage Manual
Devendra Rai,
Department of Electronics and Communication Engineering,
National Institute of Technology Karnataka,
Surathkal 575 025
INDIA
devenrai@rediffmail.com
BRUSHLESS DC MOTORS: ABOUT THE MANUAL
NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA
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ABOUT THE MANUAL
The manual describes the working of brushless dc motor simulator. The
simulator was developed as a final year project at National Institute of
Technology, Karnataka. The work is based around the trapezoidal back emf ,
,star wound stator type brushless dc motor, although the logic used here can
be applied to any type of flux distribution.
The Simulator has been written exclusively in Matlab R13. The details of all
the packages used are given in the report.
Much of the work involved the development of the core BLDC ‘mybldc’ block,
and a logical equivalent of the inverter. The idea has been to avoid the use of
SIMULINK Simpower blockset that are slow to simulate and require large
memory and phenomenal processor power.
The approach used is to reap the benefits of both Matlab and Simulink,
thereby giving a very flexible but reliable model.
Since, the product was developed as a student project, I would be glad to
receive any feedbacks on its performance.
Devendra Rai,
devenrai@rediffmail.com
Department of Electronics and Communication Engineering,
National Institute of Technology Karnataka,
Surathkal – 575 025.
INDIA
BRUSHLESS DC MOTORS: DISCLAIMER
NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA
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DISCLAIMER
The present manual is the result of the undergraduate project carried out at the
National Institute of Technology, Karnataka-Surathkal. The purpose of the manual is
to make available the simulator as a freeware and to enable people to work and
improve the product.
Commercialization and copy rights regarding this work should not be done as it
would be a disgrace to all the individuals who have helped me free of cost. Let
education and knowledge be free.
However, neither the author nor the institute ‘National Institute of Technology
Karnataka-Surathkal’ shall be held liable for any direct, indirect or consequential
damages with respect to any claims arising from the content of such a
note/manual and/or the used made by anybody of the information contained
herein.
BRUSHLESS DC MOTORS: SYSTEM REQUIREMENTS
NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA
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SYSTEM REQUIREMENTS AND OTHER IMPORTANT INFORMATION
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MATLAB Version 6.5.0.180913a (R13)
Operating System: Microsoft Windows XP Version 5.1 (Build 2600)
Java VM Version: Java 1.3.1_01 with Sun Microsystems Inc. Java HotSpot(TM)
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MATLAB Version 6.5 (R13)
Simulink Version 5.0 (R13)
MATLAB Compiler Version 3.0 (R13)
RAM (min recommended) 256 MB
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The Processor should be powerful. The modeling was done on a Pentium 4 (1.7
Ghz) processor.
A good graphics card to view the results
THE RESULTS OF SIMULATION ARE HIGHLY DEPENDENT UPON THE CHOICE OF THE
SOLVER. WE HAVE USED ODE113(ADAMS). SOLVERS LIKE ODE45 ARE FAST BUT
GIVE POOR RESULTS.
The main Simulink file name is ‘mybldc2_mdl2.mdl’. The other .m and .mdl
files that are supplied are required by the main .mdl file.
BRUSHLESS DC MOTORS: CONTENTS
NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA
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CONTENTS
1. Modeling the brushless dc motor ---------------------------------------------------6
(description of the mathematical modeling)
2. The core ----------------------------------------------------------------------------------10
(description of the ‘mybldc.mdl’ block that simulates the brushless dc
motor
3. The Estimation Block------------------------------------------------------------------13
(description of the control logic, modified Park’s Transform and
evaluation of the phase command currents)
4. Zero Crossing, IC, 120 deg trigger generator blocks-------------------------16
(description of the auxiliary blocks used for simulation
5. The ‘Controller_mod’ block----------------------------------------------------------19
(description of the finite state machines that control the working of the
inverter
6. The Inverter, ‘all phase’ block-------------------------------------------------------21
(description of the working of the logical inverter)
7. The ‘changer’ block---------------------------------------------------------------------23
(describes the bus relay that switches the bldc from open loop operation
to the closed loop operation)
8. The Simulink output file---------------------------------------------------------------24
(describes the output file contents where all the simulation results are
stored.)
9. References---------------------------------------------------------------------------------25
10. Acknowledgements -------------------------------------------------------------------26