Smart technology for a sustainable world

Linear and Non Linear ElectronicsClass 2 of ELG4139

Julio Pimentel, CEO Kylowave Inc.

www.kylowave.comwww.kylowaveeducation.com

School of Electrical Engineering and Computer Science

The University of Ottawa, Ottawa, ON, CA

November23rd, 2012

Class 1What you will learn Introduction on PWM modulators

Introduction on three-phase inverters

Fundamentals of Brushless DC motors

Operation of BLDC motors using six-steps control algorithm

Speed and torque control of BLDC motors

A BLDCM Control System

Note: drawing from Microchip AN885

Some general classes of power electronics circuits Families of solid state power converters categorized

according to their conversion function

AC

Vac1, f1

AC

Vac2, f2

DC

Vdc1

DC

Vdc2

DC-DC

Converters

AC-D

C

Rectifiers

DC-A

C

Inve

rters

DC

Link

AC

-AC

Co

nve

rte

rs

Cic

loco

nve

rte

rs

One of our subjects for today’s class

PWM – Pulse Width Modulation The idea is to modulate the width of a stream of pulses, keeping the

carrier frequency constant, such that the low pass frequency spectrum produces the required waveform

LP Filtered signal

HF Stream of

Pulses

PWM in Wikipedia

Introduction to 3-phase inverters 6 Transistors Power Converter

Note: drawing from Freescale AN1916

Half Bridge section

Fundamentals of Brushless DC motors BLDC Motor Cross Section

Note: drawing from Freescale AN1916

Fundamentals of Brushless DC motors Types of Back Electro Magnetic Force (BEMF)

Depends on BLDCM physical construction

Note: drawing from Microchip AN885

Trapezoidal

Sinusoidal

Fundamentals of Brushless DC motors Internal View of the Stator and Rotor of a BLDC Motor

Note: drawing from Microchip AN885

StatorRotor

Fundamentals of Brushless DC motors Three-Phase Hall Sensors

Note: drawing from Microchip AN885

120 degrees

Fundamentals of Brushless DC motors Winding Energizing Sequence

Dependent on hall sensor encoding

60 degree sectors

6 possible vectors for the magnetic field

Note that all ZEROS is open circuit and all ONES is short circuit. Why?

BLDCM Theory of Operation six-steps control algorithm

Control logic is not complicate to implement

Capable of very high speed operation

Relatively high torque ripple compared to other methods (Sinusoidal BEMF, Sinusoidal PWM, FOC, SVM, etc.)

High current ripple implies high harmonic content and higher operating temperature (for the same operating conditions)

Note: drawing from Microchip AN885

Speed control of BLDC motors

PI or PID Filter

Speed Estimator

Note: drawing from Freescale AN1916

Torque control of BLDC motors

Note: drawing from Freescale AN1916

PI or PID Filter

PI or PID Filter

Speed Estimator

Putting it all together Control Block Diagram

Note: drawing from Microchip AN885

Putting it all together

For further study Two others interesting examples on power electronics

Example #2Spontaneous switching - Rectifiers

Single phase Three phaseD1

D1N4002

V2FREQ = 60VAMPL = 10VOFF = 0 R1

1K

L110uH

C1

5u

V VI

D1

D1N4002

R1

1KV2

FREQ = 60

VAMPL = 10VOFF = 0

PHASE = 120

D2

D1N4002

L110uH

C1

5u

D3

D1N4002

D4

D1N4002

D5

D1N4002

D6

D1N4002

V3

FREQ = 60

VAMPL = 10VOFF = 0

PHASE = 240

V1

FREQ = 60

VAMPL = 10VOFF = 0

PHASE = 0

I V

V

Smoothinginductance

Example #3Forced switching phase controlled rectifier DC-DC Converter

R320

V2TD = 0

TF = 10nsPW = 30uPER = 100u

V1 = 0

TR = 10ns

V2 = 2

L1

5mh

V3

20V

D1

D1N4002

C1

10n

Q1Q2N2222

R410

I

VV1

FREQ = 60

VAMPL = 50VOFF = 0

PHASE = 0

R3100

X12N1595

V2TD = 3ms

TF = 10nsPW = 0.2ms

PER = 16.6667ms

V1 = 0

TR = 10ns

V2 = 5

L1

5mh

R4

1k

V

V

V

ConclusionResources available Orcad version 16.3 Student Edition – Free

http://www.cadence.com/products/orcad/pages/downloads.aspx

NOTE: The student edition has limitations in terms of # of components, # of pins, etc.

We will publish a copy of the example circuits

The internet has many useful links Search for “ pspice and power and electronics”

References on Power Electronics This is one of the best references

Erickson, R. W. & Maksimovic, D., “Fundamentals of Power Electronics,” 2nd Edition, University of Colorado, Boulder, http://ecee.colorado.edu/copec/book/slides/slidedir.html

These are good references as well Ramshaw, E. & Shuumman, D. C., “PSpice Simulation of

Power Electronics Circuits: An Introductory Guide,” Springer Verlag, 1996

Ferrieux, J. P. & Forest, F., “Alimentation à découpage -Convertisseurs à résonance: principes, modélisation, composants,” Collection technologies, Masson, Paris, 1987, ISBN 2-225-81205-5

Tolyat, H. A. & Campbell, S., “DSP-Based Electromechanical Motion Control,”CRC Press, 2003

References on Control of BLDCM 1) Leonard N. Elevich, “3-Phase BLDC Motor Control

with Hall Sensors Using 56800/E Digital Signal Controllers,” Freescale Semiconductor, AN1916, Rev. 2.0, 11/2005

2) Padmaraja Yedamale, “Brushless DC (BLDC) Motor Fundamentals,” Microchip Technology Inc., AN885, 2003

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K-ECS Functionality

Functional Layout

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Q & A Thank you

My contact:

Julio Pimentel

jpiment@kylowave.com