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A microprocessor-based speed controller for DC motors

Abstract

The introduction of microprocessors into electric vehicles has opened many interesting possibilities for improving the operation and maintenance of such automotive systems. On the other hand, microcomputer-based motor control systems are playing an ever increasing role in research on applied electronics. In this paper, a microcomputer-based digital dynamic control system (DDC) for a de motor is described. The description includes motor identification and corrector digital implementation, as well as precision analysis of the control system. The influence of poles and corrector gain on the system response is also presented, this allows the choice of appropriate parameters for the design of a lag-lead controller. The application of such a controller with a low power dc motor verifies the theoretical approach and reveals the necessary information to analyse the speed control system stability of a chopper-fed de motor using the same controller.

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A microprocessor-based speed controller for DC motors

Author: Bertran Albertí, Eduardo,Herranz, J,Martinez, L,Miguel, J,Munilla, I.
Year: 1983
Source: https://upcommons.upc.edu/bitstream/2117/87228/1/A%20microprocessor%20based%20speed%20controller%20for%20DC%20motors.pdf
A Mic op ocesso
...
based
Speed Con olle
o
DC
Mo o s
by
P o .
E.
Be U1,
J.
He anz, L Ma inez,
J.
Miguel and
I.
Mu nil la
College
o
Enginee ing and Telecommunica io n
iU_P
8
),
Ba celona
The in oduc ion
o
mic op ocessO s in o elec ic ehicles has
opened
many in e es ing possibili ies o imp o ing he ope a ion
and
main-
enance
o
such
au omo i e
sys ems. On
he
o he
hand, mic o-
compu e -based
mo o
con ol sys ems a e playing an e e inc easing
ole
in
esea ch
on
applied elec onics.
In
his pape , a mic ocompu e -
based
digi al
dynamic
con ol sys em
(DDC)
o a de
mo o
is
desc ibed. The desc ip ion includes
mo o
iden i ica ion and
co ec o
digi al implemen a ion,
as
well
as
p ecision analysis o
he
con ol
sys em. The in luence
o
poles and co ec o gain on he sys em
esponse
is
also p esen ed, his allows he choice o
app op ia e
pa ame e s o
he
design
o
a lag-lead con olle . The applica ion
o
such a con olle wi h a low powe de mo o e i ies he heo e ical
app oach and e eals
he
necessa y in o ma ion o analyse
he
speed
con ol
sys em s abili y o a choppe - ed
de
mo o
using
he
same
con olle .
ln odudion
..
....-p
-
------:-:::-~~---:-:;'i"
..
-.-::c.c----------,
'6
. '
I J s
..
>-1
-
-1
I I
I J
l:
0/A
I
.0,/0
I I
'
I
______
;
----------------- ---- ----
--
---1
I
-
c.
l
·~·.-·
--~
•&•••--
0
......
""
......
T--~
......
..
,
..
-
..
.........
,
...
LSI
echniques de elopmen has
caused digi al elec onic de ices o
become much smalle , as e
and
cheape ;
consequen ly,
he leld
o
au omo i e elec onics
has
been con-
side ably
b oadened
due o mic o-
compu e
u iliza ion. In 1977 he i s
mic op ocesso was
in oduced
in
he
Oldsmobile
To onado
as
pa
o
he
spa k
;>lug
iming ci cui .
In
hese
uel- ehicles he mic op ocesso
is
delega ed o
pe o m
he
<!ngine
con ol and p o ide aluable in o ma-
ion o he d i e . On he
o he
hand.
mic ocompu e -based
con ol
o
~lec ic
ehicles p o ides a highe
e iciency. allowing speed adjus men
o
o que
con ol.
amely,
bo h
igni ion and iming
con ol,
as
well
as
cylinde selec ion. which cons i u es
he main con ol asks in a uel- ehicle
and a e eplaced by a
dosed-loop
digi al
con ol
in he elec ic ehicle.
~o eo e ,
by changing only he
con ol
p og amme, di e en se ices
.:an
be
ob ained
wi h he same p opul-
sion sys em. This e sa ili y also allows
o implemen di e en kinds
o
~lec ic
ehicles ( ans. cabs, ai po
ucks) wi h
he
same p opulsion
sys em. The low
cos
and
easibili y
o
mic op ocesso s
is
ano he
signi ican
eason o hei use ei he as choppe -
ed de
mo o
con olle s o as in e e
con oUe s when ac
mo o s
ace used.
F"~
1
Func ion•
bloc: c
di8Qnm
o
he
mic ocompu'lll
~
com o
s sam
As
ega ds he
mo o
selec ion o
? o esso
E.
13e an.
J.
Hemsnz.
L.
Ma (nez.
J.
Miguel
and
I.
Munllla a e
wi h
he
Depa men
o
Sys ems
Con ol. The
Collage
o
Enginee ing
and
Telecommun'-
ca ons (U.P.B.l.
Jo dl
Gl ona SaiQIIdo,
5/N,
Ba celona
34.
Spain.
an dec ic ehicle. i
canno
be made
by ..:onside ing he
mo o
se ices
only, bu mus ake in o accoun he
ela ionship be ween
mo o
se ices
and he
<!SSOcia ed
elec onic
con ol.
F om [he elec onic con ol poin
o
iew.
ac
mo o
..:on ol
is
mo e
complex. Howe e . whe eas a de
mo o
a ely has a con e sion
e iciency bigge han 85%.
ha
o
an
ac mo o
is
app oxima ely 90%. E en
allowing o
impo an
losses
in
he
con ol sys em. he global e iciency
o
he p opulsion sys em-con ol
bene i s
by
using ac. Finally. ene gy
eco e y
is
simple o he de
mo o
which cons i u es he bes al e na i e
when wo king a low ol ages.
Digi al sys em
This pape discusses a digi al sys em
Z2 ELECT
..
IC
VEHICLE
DEVELCPMEN'TS SUMME
..
11113
which uses a Rockwell Aim-65 mic o·
.:ompu e o con ol he speed
o
a
de 5e omo o . Fo his applica ion.
he Rockwell Aim-65 mic ocompu e
is
used o implemen
he
sampled-da a
eedback .:on ol. and he mic o-
..:ompu e speed
con ol
sys em
is
shown
in
Fig. I. The ac ual speed
is
ob ained
by means
o
a achogene a o .
I s
ou pu
is
compa ed
o
he
e e ence
inpu
and he e o
is
hen compen·
sa ed
by
he
mic op ocesso whose
ou pu
p o ides he
co ec ed
con ol
signal o he p eampli ie . The se o-
ampli ie
is
d i en by he p eampli ie
and
p o ides he
ou pu
signal o he
mo o .
OC
mo o
model
An
impo an
elemen in he
analysis
and
design
o
a speed con ol
sys em
is
he choice
o
model o he
~
....
~ -
;.
,. _ .
-.
..
. -.
-
~~
"l'l l-
1UX'
~
·s
~D
·---
ms s:
1-"'-
...
-
~
,.,..
I
'MS
~C:A.I..
.
"Dc:.DDaq.
I I
~
~
-,-
~~
0 l I
lz.
s
"'
S'
..
,.
o~
la
1!
.A iO lll S
.4A/~c!>
. .
~
DINT
.
I•
...
:1
iS~
w;!
0 '
11
~
~
CJ.Oeo<...
lb.
CVIA)
Fig. 2
Func ional
sc:hame
o
he
analog
in111 ac:e
u..ci
in
he
expe imen
powe ac ua o . Co ec mo o iden-
i ica ion
is
he esul
o
measu ing he
mechanical ime cons an
as
well
as
he s a ic gain.
Mechanical ime cons an
A s ep inpu ol age
is
applied
o
he mo o a ma u e and he exponen-
ial ise
o
he mo o speed
is
measu ed on an oscilloscope. Thus.
b)'
gene a ing a low equency pulse ain
in
he
D/A
con e e ou pu . he
co esponding achome e ou pu can
be
ob ained bemg he ime cons an
7>.~
he ime equi ed
o
he acho-
me e ol age
o
ise
o
63
.
~<::;
o
i s
inal
aiue.
S a ic eain
The~
mo o s a ic
gain
K0 can be
ob ained
by
gene a ing a
signal
in
he
D/A con e e ou ou and eadinc he
co esponding achome e ou pu-
by
means
o
he AID con e e .
Mo o ans e unc ion
~o o
ans e unc ion can be
w i en:
w0
(s
1 =
V(s)
whe e K0
<Y
205 ad.sec- 1 / ol . and
Tc
""'
0.::!5 secs o he mo o used
in
he expe imen .
A/D
Con e sion
Assemble
P og amme
Figu e 2 shows he unc ional
scheme
o
he analog in e ace o he
Rockwell
Aim-65
mic ocompu e
sys em which
has
been de eloped
in
he Depa men o Sys ems Con ol
(ETSIT. Ba celona). The design
is
easily adap able o any -o he
compu e .
l
uses
eigh mul iplexed
inpu s and one ou pu , and
has
been
designed o con ol low-powe de ices.
LDA
*DF
The mic ocompu e con ols he
analog inpu h ough he so-called VIA
ia se
o
p og ammable
inpu /ou pu
po s)
by
using an Aim-65 sys em.
B
means
o
he usua sub ou ine
he main p og amme
in
·Basic makes
he ollowing sequence
oi
assemble
ins uc ions o he A/D con e sion:
. DEFISE VIA'S OPERATIOS
MODE
STA
LDA
STA
LDA
STA
OP
NOP
LDA
STA
LEVl .
LDA
SEC
SBC
BNE
JMP
A003
: 3F
A0Cb1
.
~-
:::z::
_,
:
A00l
=i=
27
A00
AOOl
#07
LEV
1
C0D 1
. SELECT ANALOG
1! 'PL
~
T
.
HOLD
:END OF
CONVERSIOJ' '~
RETURN
TO
BASIC
Co ec o
Digi al
Implemen a ion
By
using
he bilinea ans o ma ion a
Jag-lead
con olle has been p o-
g ammed
in
he mic ocompu e . i s ans e uncnon being:
G
(s)
= K
L!:..C.
c
s+p
The co esponding
Basic
p og amme
is
gi en
below:
ELECTRIC
VEHICLE
DEVELOPMENTS
SUMMER
1983
23
'
..,
5
7
10
15
18
20
22
DlM
X<4>
DIM
Y<4>
INPUT
"TRNS.
Z=
l"
; FR
IF
FR:::ol
GO
TO 300
INPUT
"SAMPLING PERIOD" ; T
INPUT
"DELAY" ; Z
INPUT
"C" = ; C
24
INPUT
"P'' = ; P
26
INPUT
"K"
= ; K
28
INPUT
"DER=l,
BlLIN.~";
FT
3(J
IF FT=l
GO
TO
38
32 o
1 =
<K•c•T
-2•K> <2+P*T>
34 01 =
<2•K+K*C•T>/<2+P*T>
36 Q3 = <P*T
-2>/<P*T+D
38 FOR I
=~TO
4
~
X<D=0
-4-2
Y<D=0
44
~EXT
I
Mo o
esponses
o
a 5 ol s-s ep in
he
se -poin ha e been
ob ained
o
di e en
alues
o
p ( igu e 3)
and
K
( igu e
4).
Being
he
co ec o
gain a
cons an ,
he o e shoo
and
damping
equency
o
he
ou pu
will
dec ease
i
he
co ec o
pole becomes mo e nega i e,
as
i can
be
seen in igu e 3.
On
he
con a y,
a g ea inc ease
o
K
makes
he
damping equency
componen
bigge when p
and
c a e ixed ( ig. 4 ).
S abili y Analysis
Figu e 5 shows he
sys em
block
diag am whe e he
mic ocompu e
compu a ion
lag
has
been
modelled
by means
o
a delay
block
o
T
seconds.
Choosing c=4 i s ans e
unc ion
can
be ob ained, om he
sys em
block diag am as ollows:
(100+10p}z3 +
(1
Op-IOO+l5.J8K)z1
+ 30.76Kz +
!5.J8z
= 0
I
he
sys em
is
s able all
he
oo s
Zi
o
his
equa ion
will lie inside
he
uni
ci cle,
o
I
Zi
I<
I.
Choppe - ed
DC
Mo o
Figu e 6 shows
he
unc ional
block
diag am
o
a de
mo o
which
is
ed by
a c
hoppe .
Di e ences
be ween
his
scheme
and
ha
in igu e 1
can
easily
be es ablished.
Thus.
p
eampli ie
and
s
e oampli ie
a
e
eplaced he e by
pulse g
ene a o
and
c
hoppe
. F om
he
poin
o
i
ew
o
s a
bili y i me:ms
ha
a new
block
diag am mus be anaJ
ys
ed.
In
which
case. he c
hoppe
ans
e
un
c
ion
is
d
e e mined
by i s
du y
cycle:
V(s) = E
IJ(s)
211'
whe e E ep esen s
he
ba e y
ol age.
~8
POKE
40962. 255
5(J
X
<a>=
X
<I>
52
X<I>=X<2>
53 X
<~=X<3>
54
X
<3>
= X
<4>
55
y
<0>
= y < 1 >
56
y
<1>
= y
<2>
57 y
<2>=
y
<3>
58
Y<3>=Y<4>
60
POKE
04
.
~
e-Ts
( l - e·Ts ) K s + c
Km
'
S'T'P
TniS'-:n
H(s) =
65
POKE
05.
12
I + K K + e·Ts ( l - e-T
s)
K
~
A S s + p
Km
1"TT1S
+ I
70
W=USR<R>
75
U =PEEK
<40959>
= e·Ts ( l - e·Ts ) K.820
85 X
<4>
=
<U-!2T>
• 08
88
IF
FR
=I
GO
TO
350
s1 + sp + e-Ts ( 1 - e
·Ts
) K.l
5.
38
89 IF
FT=
l
GO
TO
250
91
Y<4>=X<J>*Ql+X<4>
And
i s pulse ans e
unc ion:
~~
102
104
110
120
• Q2 -y
<3>
•
Q3
FOR
L=0
TO
Z H(z) = 820K
(zl
+
2z
+
I)
(lOO+ 10p)z3
+(lOp-
100 +
1538K)zl
+ 30.76Kz +
1538K
150
254'
252
255
300
310
32~
350
3
51
360
370
380
40(.1
G = 3 • 5
~EXTL
0 =
<Y
<4>.
13.5> + 127
POKE
40960 . 0
GO
TO
5~
F
o
pa icula alues
o
K. p
and
c,
he s abili y
o
such a sys em can be
de e mined om he loca
i
on
o
he
oo s
o
he cha ac e is ic
equa ion
y
<4>
= Y
<J>
+
K•X<4>-K*X<3>+K*C•T•X<4>
y
<4>
= Y
<4>
I <1 +
P•T>
GO
TO
LOO
INPUT
Nl.JM.
COEFFICIENTS
IN
DECREASING ORDER:
A0.
Al.
A2,
A3.
A4.
INPUT
DEN
. COEFFICIENTS :00. Bl,
B2,
B3,
B4
GO
TO
38
Y
<4>
= X<4>*
A<0>+X<J>•
AI
+X<D*
A2
Y
<4>
=
Y<4>•X<I>•AJ+X<4>*A4
Y
<4>
=
Y<4>-Y<J>•BJ-Y<2>*B2-Y<I>•BJ-Y<0>*84.
Y
<4>=
Y<4>
/80
GO
TO
100
END
Di e en
asks in his
p og amme
a e explained as ollows:
10-28
300-310
60-85
32-58
91
110-120
250-252
310-380
100-104
Inpu
pa ame e s
Sample
e o
signal
Compu e
y( }
Ou pu
o
Dl
A
con e e
Co ec
he
compu a ion
o
y( )
by means
o
he bilinea
ans o ma ion
Find
y( )
by
means
o
he
z- ans onn
Delay
in oduced
by
he
usua y
o
expe imen
he
in luence
o
he
sampling
pe iod.
Op ions:
-Di ec
compu a ion
(22,
24,
26).
-
Compu a ion
by
means
o
z- ans onn
( 1
l.
3119,
31
)
-Modi y
sampling
ime
(29).
ELECTRIC
VEHICU
DEVELOPMENTS
SUMMER
1113
Mo eo e ,
an
impo an
class
o
pulse
gene a o s
can
be
modeUed as a ze o-
o de -hold
ci cui
I l I whose
ans e
unc ion
can
be
w i en
as
ollows:
I - e-Ts
G(s)
= G0 (....:....-
5
~-1
whe e T
is
he mic op ocesso
sampling ime.
By
i
n oducing
bo h
choppe
and
pulse gene
a o
an
s
e
iunc
ions ( ig.
5)
,
he
sys em
cha
ac e
is ic e
qua
ion
can
be
ob ained,
in
o de
o
e i y
he
s abili y
o
he
sys em.
Conclusion
The
applica ion
o
a pe sonal
compu e
on a de
mo o
con ol
has
b
een
desc i
bed.
Th
e s
udy
shows
ha
he co
n
ol can be used sa
i
s ac o ily
in se omo
o
applica i
ons
a
nd
as a
speed
con ol.
As
o i s
u iliza ion
in
e
lecoic
ehicles.
he
sa
me
c
on
c
ep
:1
pplies.
In
his case, he p
owe
is
s
upplied
o
he
mo o
h ough
a
c
hoppe
{SCR o ansis o ), his
be
ing
he
pulse g
ene a
o
o in e
ace
be ween
he
mic ocompu e
and
he
powe
s age.
S abili y
analysis
is
also
gi en when
he
pulse g
ene a o
is
modelled
as
a
ze o-o de
ho
l
d.
Real
ime
con ol
cons i u es
he
mos
s ingen
demand
on
mic o-
p ocesso
based
equipmen .
Compu a-
ion
lags, con e sion imes
and
ope a ionaJ
accu acy
acqui e a ele an
d
esign
signi icance.
Hence,
esponse
s
peed
p oblems
wiTI
a ise
i
he
og amme
execu ion
ime
is la ge.
e e o e,
maximum
con olled
mo o
p
Th
spee
p d
will
be
de e mined
by
mic o-
ocesso
minimum
sampling
ime.
Ti is
pe iod
is
calcula ed
by
conside ing
he
AID
con e sion
ime
he
con ol
algo i hm
compu a ion
ime
and
he
0/A
con e sion
ime.
Finally,
p og amming
in
Basic
e ea~
ha
in e nal
ope a ions
can
be
made
wi h
g ea llccu acy
a
he
expense
o
educing
p ocessing
speed.
On
he
o he
hand,
he
use
o
assemble
language
imp o es
he
speed
o
esponse.
while
ope a ions
a e
made
wi h
la ge
e o s.
The e o e,
his
ade·
o
be ween
speed
esponse
and
algo i hm
ope a ions
accu acy
con-
s i u es
he
i s
p oblem
o
be sol ed
when
designing a digi al
con olle .
Re e ences
I
Linn.
A. K.
and
Koespel,
W.
W
••
"A
mic op ocesso
speed
con ol
sys em".
IEEE
T ans.
lnd.
Elec on
.
Con .
lns um.
Vol.
IECI-24,
No.
3.
Augus
1977.
2
Cen
da
go a
-G
ala a.
M.
and
P a s, J
.•
"Yehiculo
eiEc ico con alimen aci6n
sola ".
P oyec o
Fin de Ca e a, ETSIT
de Ba celona.
1980.
3 Modula Se o Sys em
MS
ISO Book 3
DC.
Synch o
S.
AC, Ad anced
Expe imen s".
Feedback
Ins umen s
Limi ed.
4
Cadzow
.
J.
A.
and
Ma ens. H.R ..
"Disc e e- ime
and
Compu e
Con ol
Sys ems".
P en ice·H
aD.
INC.
En~ewood
Cli s. New
Je sey.
.
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Fig. 4
Speed
...--
o
5
a ,.._
(K •
0.07.
0.1,
O.SI
OI•ITA'
co~A C"WI!!
I
I '
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ll ~T
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Fig. 5
S~m
block
die -m
I
whe e
nn
"'"0.25
secs
'
Km""' 205 •
KT
:
25.l<P
I
KA
: 0.75
T : 0.2
secs.
I
EVC
-Expo
.83
Fig. 6
Sp.d
con1 01
- n-m
a •
choppe
ied
de
mo o
Washinl! on.
DC
(
19
Jul
1983)-
The
Elec i~
Vehicle Council
announced
oda~
ha
13
o ganisa ions a e so a
commi ed
o
exhibi
p oduc s
and
se ices du ing he Council's
Expo
"83
Conie ence
and
Showcase.
The
in e ·
na ional
e en will be held
a
he
H a
Re2enc Ho el in
Dea bo n.
M.ichigan om:
Oc obe
4 o 6. 1983.
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..
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• I
I
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•••
, I
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:
1 • : '
....
••
Exhibi o s:
Gene al
Mo o s
Co po a ion
Fo d
Mo o
Company
De oi
Edison
Company
Ea on
Co po a ion
Long
Island
Ugh ing
Company
G umman
Allied Indus ies,
lnc
Albe Enginee ing,
lnc
Ene gy
De elopmen
Associa es
(Gul +
Wes e n)
Lucas Chlo ide EV Sys ems
L d
Fia
SpA/IVECO
B own,
Bo e i, & Cie
Tennessee
Valley
Au ho i y
AVERE
In o ma ion
is a ailable
om
he
Fig. 3 Speed
~ o
5
ol~
(p
•
3,
5.
81
Council,
llll-19 h
S ee
NW.
Washing on, DC 20036.
ELECTRIC
VEHICLE
DEVELOPMENTS
SUMMER
1983
25