Download Influence of Voltage Drop to Electric Drive with Induction

Recent Researches in Circuits, Systems, Control and Signals
Influence of Voltage Drop to Electric Drive
with Induction Motor and Voltage Sourced
Inverter
P.Beneš, J.Fořt and M. Pittermann1
Abstract — This paper solves problematic of immunity
from the voltage drop of the power supply of the electric drive
with induction motor with Voltage-Fed inverter. There are
reflected opportune control algorithms for the quickly to
change of working regime from full load in regime “drive” to
“no-load” regime (to achieve for approximately constant value
of voltage in capacitance in DC-link) and opportune control
algorithms for quickly to return to original working regime
after the regeneration of energy supply. There are also
referenced the variants of adaptation of power circuits for to
achieve a higher of immunity from the voltage drop of the
power supply.
Keywords— electric drive with induction motor, electric drive
with voltage sourced inverter, voltage drop
ACKNOWLEDGMENT
This research work has been made within research project
of Czech Science Foundation No. GACR 102/09/1164.
I. INTRODUCTION
E
LECTRIC drives with induction motor (supplied from
voltage sourced inverter) is often used type of drives.
Today this type is used for the most demanding applications.
A fundamental disadvantage of the drive with asynchronous
motor and voltage sourced inverter (compared with older types
of DC motor drive) is notably higher complexity of the drive.
Induction motor is happening during the transition tends to
oscillating behavior. Then there is the danger of the state
1
Manuscript received July 31, 2011. This research work has been made
within research project of
Czech Science Foundation No. GACR
102/09/1164.
P.Beneš is with West Bohemia University of Pilsen, Czech Republic
(corresponding author to provide phone: 420-377-634493; fax: 420-377634402; e-mail: [email protected]).
J.Fořt is with West Bohemia University of Pilsen, Czech Republic
(corresponding author to provide phone: 420-377-634415; fax: 420-377634402; e-mail: [email protected] ).
M.Pittermann is with West Bohemia University of Pilsen, Czech Republic
(corresponding author to provide phone: 420-377-634423; fax: 420-377634402; e-mail: [email protected] ).
ISBN: 978-1-61804-035-0
189
where the power is restored may have to connect the inverter
output voltage to the motor in the wrong value of frequency or
phase (due to the current value of the motor shaft rotation
speed or due to the current value of angle fading magnetic
field in the motor).
Hence the "safest" behavior "simplest" drives such
behavior, when, after intervention by the under-voltage
protection will shut down the drive, then a deceleration and
after appropriate time delay occurs re-start the drive from
"zero" initial conditions. Such behavior would consider
coming to the least demanding applications (eg. typically
drives a fan, etc.) and the simplest algorithm for inverter
control.
Manufacturers of frequency converters, however even these
"simple" cases often improve the behavior of these drives by
editing "additional" features (eg. feature called "flying start"
drive, the wait is not required to stop the motor).
In addition, this procedure is unsatisfactory for a significant
number of applications where the influence of these
considerable delays may occur to an unacceptable negative
effect on the driven equipment.
Therefore, from this perspective, there is influence of these
failure modes to drive with asynchronous motor powered from
the voltage inverter.
Therefore, the drive to ensure greater resistance against
these agents will be given editing power in the power scheme
in the control circuits.
II. FAULT CONDITIONS
These faults are considered:
1) Short-term reductions in voltage
2) Long-term decline in the value of supply voltage
3) Take special conditions leading not only to decrease
tensions, but also to other negative influences (for example
the unbalanced supply)
4) Faults in regenerative braking mode
Attention will be devoted mainly to cases according to point
1 and point 2.
III. MEANS OF ENSURING GREATER RESISTANCE
DRIVE AGAINST VOLTAGE DROP
Increased resistance to negative influences mentioned in
Recent Researches in Circuits, Systems, Control and Signals
chapter II can be implemented as follows:
A) Using a more complicated power circuit of the drive,
allowing delivery of sufficient energy to the capacitor
and inverter fault conditions listed in chapter 2
B) Using a better method of controlling the drive
C) Increased tolerance of the drive in terms of allowed
values larger drop in voltage on the capacitor
D) Ensuring appropriate and rapid return to original
working condition
Fig. 4.3 Drive with step-up converter
The drives described on Fig.4.2 and on Fig.4.3 are able to adjust
small value in the input to high value in DC-link.
IV. MORE COMPLICATED POWER CIRCUIT
Power circuit can be completed by these devices:
a) active rectifier (see Fig.4.2)
b) other type of converter for stabilization of voltage
c) other external source for DC-link
Other methods are methods (for a relatively short voltage drop),
which used tanks to store energy. For illustrative image is shown in
Table 1 some examples of storage elements corresponding to usable
energy (for that mode) and the period T during which it would be
possible to cover that deficit 1kW output.
These options mean more complicated drive power circuit
(ie.a higher price than the basic variant in Fig.4.1.)
TABLE 1
Storage elements
and its operating mode
Capacitor C=1mF, VN=540 V,
UMin=0,9 UN
Capacitor C=1mF, VN=540 V,
UMin=0,8 UN
Capacitor C=1mF, VN=540 V,
UMin=0,7 UN
Capacitor C=1mF, VN=800 V,
UMin=0,1 UN
Super-Capacitor C=1F,
VN=200 V, UMin=0,1 V
Inertia J= 0,4 kg m2
nN= 3000 RPM, nMin=0,9 nN
Inertia J= 0,4 kg m2
nN= 3000 RPM, nMin=0,8 nN
Inertia J= 0,4 kg m2
nN= 6000 RPM, nMin=0,1 nN
LiFePo battery 80Ah, 12V
Fig. 4.1 Basic variant of drive
Fig. 4.2 Drive with active rectifier
Active rectifier (4.2) bring some advantages in the field the
reducing of negative influence drive into supply grid
(minimize the harmonics components in the input current). In
addition, this drive provides regenerative brake. In some
application its main advantage is the possibility to increase the
input voltage.
In some applications (which does not require a regenerative
brake, etc.) can be used according involvement as Fig.4.3.
This configuration of power-converter is often used in
applications with 1-phase supply (to achieve a low content of
higher harmonics in the input as so called APFC).
Energy
T
28 J
28 ms
53 J
53 ms
74 J
74 ms
320 J
320 ms
20 kJ
20 s
3 kJ
3s
13 kJ
13s
76 kJ
76 s
3,5 MJ
1 hour
The simplest variant is the "only" increase the overall value
of the capacity of capacitors in DC-link (first 3 rows). For
better utilization of storage element (eg capacitor with a higher
permitted discharge) would be the storage element not directly
connected to the DC-link but by using another converter (for
example see Fig.4.4).
Fig. 4.4 Drive with energy storage with own converter
ISBN: 978-1-61804-035-0
190
Recent Researches in Circuits, Systems, Control and Signals
V. CONTROL ALGORITHMS
The drive according the Fig.4.1 (with the basic
configuration of power circuit) is not able to operate
continuously with full power during the voltage drop.
According to Table 1 would have to quickly discharge the
capacitor in the DC-link. Therefore it is necessary to rapidly
reduce the output drive.
Fig.5.1 shows the transient corresponding requirements of
the rapid drop in performance for simple control algorithm of
induction motor (eg, scalar control algorithms). The actual
process output is not slow. Therefore, it could cause a large
discharge of capacitor in DC-link.
shock could occur for example n the event that during the very
time when the inverter decreased motor speed (ie, the inverter
would have a higher recovery rate than your current value of
engine speed).
It is also necessary to respect the magnetic flux in the motor.
Fig.5.3-5.5 shows the waveforms after restoring power to the
motor. To illustrate, there are shown transient, when after the
restoration of power supply should be the torque motor zero
(which in the aftermath of the transition state actually will).
Fig.5.3 shows the case that the induction machine could
magnetic flux disappear. Then jump of the supply voltage as
well as "correct frequency and size" (ie. with regard to the new
steady state) results in current and torque surges (motor is
excited to form oscillating happening).
Fig. 5.1 Time chart of scalar control algorithms
Fig. 5.3. Restoration work of work of inverter, (induction motor
without magnetic flux)
Fig.5.2 shows the same transient but with the rapid control
algorithm of induction motor (for example vector control
algorithms). The transient time was reduced.
Fig. 5.4. Restoration work of work of inverter, (incorrect angle of
the voltage vector to the current position mg.flux, which
remained in the engine during a power outage).
Fig. 5.2 Time chart of scalar control algorithms
If the inverter has been switched off (eg due to the large
drop in voltage on the capacitor due to the intervention or
protection), it is necessary to ensure that restoration work did
not occur inadmissible the inverter current or torque. Torque
ISBN: 978-1-61804-035-0
Fig.5.4 shows the condition when the induction machine kept
mg. flux but is used in the restoration of a different phase shift
inverter voltage than would correspond to the mg. flux (ie, even a
191
Recent Researches in Circuits, Systems, Control and Signals
"error only" in the angle can lead to oscillating action). So for the
restoration of power with minimal current and torque must be
respected and the current value of the angle of mg. flux (eg see
Fig. 5.5), where transient minimized.
indicated increased resistance against these errors in the
supply and demand both in terms of the complex arrangement
of power circuit or in a sense more complex regulatory
structures. There were also some of the courses outlined in
the respective transition states. More information can be
traced in the following literature.
REFERENCES
[1] Cibulka J.:Vybrané dynamické jevy trakčního pohonu s asynchronním
motorem. Ph.D.-these WBU Pilsen 2004
[2] Cibulka J., Pittermann M.; Reakce asynchronního motoru s
napěťovým střídačem na poruchové stavy vyskytující se při provozu
trakčního pohonu. In XXVIII.celostátní konference o elektrických pohonech
Plzeň 2003, str 148-153
[3] Cibulka J., Pittermann M., Zeman K.; Kvalitativní posouzení
regulačních zásahů užívaných při dlouhodobém přerušení dodávky energie do
stejnosměrného obvodu měniče. In XIX. Mezinárodní sympozium učitelů
elektrických pohonů SYMEP 2002, Liberec 2002, str 150-155
[4] Cibulka J., Zeman K.; Simulace dlouhodobého přerušení dodávky
energie do ss.obvodu měniče trakčního pohonu. In Celostátní konference
Elektrické pohony a výkonová elektronika EPVE 2001 Brno 2001, str. 56-61
[5] Danzer J..: Elektrická trakce I.,II.,III.. Skripta ZČU Plzeň 2002
[6] Flajtingr, J.; Kule L.: Elektrické pohony se střídavými motory a
polovodičovými měniči. Skripta ZČU Plzeň 2002
[7] Kůs, V. : Nízkofrekvenční rušení. Skripta ZČU Plzeň 2003
[8] Kůs V.: Vliv polovodičových měničů na napájecí soustavu BEN 2002
[9] Podrapský J.: Napájecí jednotky frekvenčních měničů Siemens.
XXX.celostátní konference o elektrických pohonech. Plzeň 2007, str.160-166
[10] Vinh, D.Q..:Dynamické vlastnosti asynchronního motoru napájeného
měničem kmitočtu.. Dizertační práce ZČU Plzeň 1996
[11] Vondrášek F.: Výkonová elektronika I.,II.,III. Skripta ZČU Plzeň
1994
[12] Zboray, L.; Ďurovský F.; Tomko J.: Regulované pohony. Vienala
Košice 2000
[13] Zeman K., Cibulka J.; Vybrané poruchové stavy trakčního pohonu s
asynchronním motorem. In XX-VII.celostátní konference o elektrických
pohonech Plzeň 2001
[14] Zeman K., Cibulka J.; Vybrané poruchové stavy trakčního pohonu s
asynchronním motorem. In XX-VII.celostátní konference o elektrických
pohonech Plzeň 2001, str.277-173
[15] Zeman K.; Peroutka Z.; Janda M.: Automatická regulace pohonů s
asynchronními motory. Skripta ZČU Plzeň 2004
Fig. 5.5. Restoration work of work of inverter - adhered to the
voltage angle mg. flux, which remained in the motor after a
power failure (induced voltage precision) and immediately
set to zero torque.
Fig. 5.6 shows the transition process, which is also
respected mg. flux angle (as in Fig.5.5.), but immediately set
the full value of torque.
Petr Beneš received the M.Sc. degree in electrical engineering from the
Pilsen, Czech Republic) at the
voltage angle mg. flux, which remained in the motor after a powerdepartment of Electromechanics and Power electronics in 2008. Since 2011
failure (induced voltage precision) and immediately set to full he worked as lecturer on WBU. In 2010 and 2011 he studied at the TUChemnitz in Germany. He specialized in robotics, electric drives and power
torque.
electronics.
Jiří Fořt received the M.Sc. degree in electrical engineering from the
For this purpose it is necessary to use good quality
WBU (West Bohemia University of Pilsen, Czech Republic) at the
induction motor control scheme (such as vector control
department of Applied electronics in 1996. He received Ph.D. degree in
electric drives and electric traction at WBU in 2003. Since 2000 he worked as
induction motor with embedded jet engine model, or evaluate
lecturer on WBU Pilsen.
the value of the induced voltage in the stator windings).
Martin Pittermann received the M.Sc. degree in electrical engineering
from the WBU (West Bohemia University of Pilsen, Czech Republic) at the
department of Applied electronics in 1995. He received Ph.D. degree in
electric drives and electric traction at WBU in 1999. From 1997 to 1999 he
worked as research worker in ŠKODA Research Pilsen. Since 1999 he
VI. CONCLUSION
worked as lecturer on WBU Pilsen. He specialized in electric traction, control
techniques, electric drives and power electronics.
Fig. 5.6. Restoration work of work of inverter, - adhered to the WBU (West Bohemia University of
The article dealt with the behavior problems with
asynchronous drive motor and the inverter voltage during the
short-falls and power outages. There are some variants
ISBN: 978-1-61804-035-0
192