2on cicle tèncic d'energia a la indústria
Jornada eficiència energètica en motors elèctrics
Ponents: Ana Marañon. Enginyera Indsutrial EIC
Toni Garcia. Dr. enginyer industrial. Professor UPC
Normes, disseny i ús de motors elèctrics industrials
1. Normes, disseny i ús de
Motors Elèctrics Industrials
2on CICLE TÈCNIC:
ENERGIA A LA INDÚSTRIA
Antoni Garcia (UPC-Terrassa)
Ana Marañón (AM enginyeria)Eficiència energètica en motors elèctrics
21 de juny de 2017
Can Muntanyola, Carrer Camí del Mig, 22
(P.I. Palou Nord) Granollers
2. MOTORS D’ALTA EFICIÈNCIA
1. Precedents
ESTALVI ECONÒMIC
ESTALVI ENERGÈTIC
Roughly 65 % of total power generation capacity is consumed
by electric motors. Of this total consumption, approximately 90 %
is utilized induction machines.
3. 1. Precedents
El conjunt dels accionamients elèctrics està format per:
− Motor elèctric
− Motor elèctric amb reductor
− Motor elèctric alimentat amb convertidor de freqüència (o variador de
velocitat)
En la figura 1 se presenta la distribución del consumo eléctrico entre los
diferentes tipos de accionamientos eléctricos.
5. 1. Precedents
El rendiment als motors Standard
- 8% (motors 1kW)
- 1.5% (motors 100kW)
Si es pot regular la velocitat (amb convertidor de freqüència)
- El consum es reduïria al 40%
La millora de rendiment + regular velocitat:
Estalvi de 1.140 milions d’euros (refª 0.0712380€/kWh) (per any a l’Estat Espanyol).
L’estalvi energètic (despesa econòmica) reducció impacte mediambiental.
Si per general 1kWh es produeixen 0.59kg de CO2, l’estalvi en emissions de CO2 significaria
una mica més de 9 milions de tones (per any a l’Estat Espanyol).
A la UE s’estimen 118 milions de tones d’emissions de CO2, que suposa un 25% del compromis
de reducció de Kyoto.
http://www.motors-electrics.com/
6. 2. Polítiques energètiques
APLICACIÓ DE NORMATIVA DE CONTROL DE CONSUM DE
MOTORS ELÈCTRICS
Polítiques energètiques als diferents països del mon per incentivar l’ús de
motors elèctrics d’alt rendiment
EEUU
DOE promulga la llei Epact (24/10/97) obliga que els motors que es
comercialitzin tinguin un rendiment mínim
Els motors elèctrics estan normalitzats a Amèrica segons la norma NEMA MG1
(National Electrical Manufacturers Association)
http://www.motors-electrics.com/
7. 2. Polítiques energètiques
Canadà
Llei similar EEUU, EEAct (Energy Efficiency Act 1992)
Rendiment mínim
Comunitat europea
Acord voluntari signat al 2000
FABRICANTS MOTORS + DIRECCIÓN GENERAL DE LA ENERGIA
3 categories
EFF1: Alt rendiment
EFF2: Rendiment Millorat
EFF3: Baix rendiment
http://www.motors-electrics.com/
Compromis a fabricar només motors amb rendiment millorat i alt rendiment.
8. Els fabricants de motors que signen l’acord, marquen els seus motors a la placa
de característiques amb el logotip:
2. Polítiques energètiques
http://www.motors-electrics.com/
10. 2. Polítiques energètiques
Los valores presentados en la tabla 1 resultaron de la puesta en común de los
rendimientos que podrían ofrecer los fabricantes en el estado actual de la
técnica y sin encarecer excesivamente el producto.
S’indiquen de forma tabulada els valors nominals de rendiment en funció de la
polaritat i la mida del motor.
http://www.motors-electrics.com/
11. 2. Polítiques energètiques
CEMEP (European Committe of Manufacturers of Electrical Machines and
Power Electronics)
“EFF”
16/06/2011
IEC 60034-30
Esta nueva legislación fue aprobada en la Unión Europea con el objetivo de
reducir el consumo energético y, como consecuencia, las emisiones de CO2
12. 2. Polítiques energètiques
La norma especifica los niveles de eficiencia energética para motores de
inducción eléctricos trifásico, de velocidad única, de jaula de ardilla con 2, 4 o 6
polos. Clasifica tres niveles: IE(international efficiency)
IE1: eficiencia estándar (equiparable to eff2)
IE2: alta eficiencia (high) (equiparable to eff1 or EPAct’92)
IE3: eficiencia premium (equiparable to EPAct’05)
IE4: Eficiencia Super Premium
los fabricantes no podrán poner en circulación dentro de la Unión Europea
motores IE1 a partir de esa fecha, pero todo motor fabricado anterior a esta
fecha puede ser vendido o instalado por cualquier fabricante.
15. 2. Polítiques energètiques
Quins estalvis representa?
Quina és la diferència més important entre un motor IE1 i un IE2?
Exemple:
15kW 4 pols
IE1 rendiment=88.7%
IE2 rendiment=90.6%
IE1 consumirà=15/ 0,887=16,91 kW
IE2 consumirá 15/0,906=16,56 kW; 0,35 kW menos
Suposant que els 2 treballen a plena càrrega 3000 hores, l’estalvi seria de
0.35x3000=1050kW.h
A 0.15€/kWh, l’estalvi és de 157.5€/any
Si es compara amb la diferència de preus en menys de 2 anys s’amortitza. Per
no parlar de la millora mediambiental que suposaria.
16. This explains the vast amount of initiatives and standardization efforts in the context
of energy efficiency of induction motors.
Publication of the revised IEC Std. 60034-2-1 concerning the “Methods for
determining losses and efficiency from tests (excluding machines for traction
vehicles)”
IEC Std. 60034-30-1 specifies efficiency classes for line operated AC motors.
IEC/TS 60034-30-2 shall specify classifications for variable speed AC motors.
IEC/TS 60034-31: Rotating electrical machines - Part 31: Guide for the
selection and application of energy-efficient motors including variable-speed
applications .
IEC 60034-2-1 valid for sinusoidal supply, with PWM inverter supply too
IEC/ TS 60034-2-3 determination of the rated efficiency of converter-fed
induction motors
STANDARDS
17. AC In
AC to DC
Converter
Three
Phase
Inverter
Gate
Drivers
DC Bus
Gate
Driver
Power
Supplies
Analog
Conditioning
Serial
InterfaceF2803x
12 Bit
ADC Trigger
Fault
ePWM
Module
Sync
Isolation
eQEP
Module
Commanded
Speed
Actual Speed
+
-
PI
Controller
Field
Oriented
Controller
Commanded iq
Commanded id
Phase
Current
Reconstruction
icia
Space
Vector
Modulation
Vα
Vβ
ibus
Bus
Over-
Voltage
GPIO or PWM
Speed
Calculation
ibVbus
MotorPWMs
Overcurrent
BusCurrent
BusVoltage
Processor Ground
θ(t)
θ(t)
17
18. 0 500 1000 1500 2000 2500
0
50
100
150
200
250
300
350
400
Induction motor torque-speed for variable frequency
Speed, rpm
Torque,N-m
Frequency increment: 4.6667 Hz
Base curve(solidline): 50 Hz
CONVERTER FED INDUCTION MOTORS
19. The addition of an variable frequency controller adds considerable potential
for improved energy efficiency in many electric motor systems.
The first group of applications is pumps, fans and similar with changing loads
where torque increases nearly by the square of the rotating speed of the
motor.
motor pump
valve
Supply
motorPEC pump
Supply
Power
In
Power loss
Power out
Power loss
Mainly in valve
Power outPower
In
Variable Speed DrivesConstant speed
CONVERTER FED INDUCTION MOTORS
20. The addition of an variable frequency controller adds considerable potential
for improved energy efficiency in many electric motor systems.
The first group of applications is pumps, fans and similar with changing loads
where torque increases nearly by the square of the rotating speed of the
motor.
motor pump
valve
Supply
motorPEC pump
Supply
Constant speed Variable Speed Drives
Power loss
Mainly in valve
Power outPower
In
Power loss
Power
In
Power out
CONVERTER FED INDUCTION MOTORS
21. The second group of applications are conveyors, escalators, hoists and
similar where the torque is more or less independent from speed.
The cost and efficiency benefits are smaller compared to the first group of
applications because the change of input power is linear with the speed.
CONVERTER FED INDUCTION MOTORS
24. There is a mutual influence of motor, converter, control algorithm and
parameter settings on the respective losses in motor and converter. Besides,
there is no harmonized system for the visualization or classification of the VSD
efficiency over the entire operating range yet.
Inverter and Motor Loss Components
The inverter losses Pinv :
Conduction losses Pcond
Switching losses Pswitch
The conduction loss is a product of inverter output current and a fixed voltage
drop across the transistors and diodes.
When the switching elements (usually IGBT’s) change states, the current through
and the voltage across the switch does not change instantly. The product of voltage
and current during each transition represents a switching loss, proportional to
the switching frequency.
CONVERTER FED INDUCTION MOTORS
26. Induction motor losses can be subdivided in:
Joule losses Pjoule in stator windings and rotor bars are proportional to the
resistances and the currents squared.
Iron losses Pfe (hysteresis and eddy-current losses) augment approximately
with fundamental frequency and flux level squared. More harmonic content in the
motor current yields small fast changes in flux level and minor additional hysteresis
loops causing respectively more eddy-current and hysteresis loss.
Friction and windage losses Pfr,w depend on motor speed.
Stray load losses PSLL(additional losses) are due to time and space harmonics
and leakage flux caused by magnetic saturation, practical slot geometry and supply
distortions. They increase with load current and harmonic content.
Decrease with increasing switching frequency in the converter.
CONVERTER FED INDUCTION MOTORS
27. IEC 60034-2-1 valid for sinusoidal supply, with PWM inverter supply too
IEC/ TS 60034-2-3 determination of the rated efficiency of converter-fed
induction motors
EFFICIENCY DETERMINATION OF CONVERTER-FED INDUCTION MOTORS
A. Boglietti, A. Cavagnino, M. Cossale, A. Tenconi and S. Vaschetto, "Efficiency determination of converter-fed induction motors: Waiting for the IEC
60034–2–3 standard," 2013 IEEE Energy Conversion Congress and Exposition, Denver, CO, 2013, pp. 230-237.
doi: 10.1109/ECCE.2013.6646705
Efficiency decrease of 1–2 % at full load (Mohan 2003)
29. TIPO AM HE 200LP2 AM 200LLA2
Clase Eficiencia (CEM EP) EFF1 EFF2
RENDIM IENTO [% ] 93,1 91,6
Potencia EJE [kW ] 30 30
Potencia Red [kW ] 32,22 32,75
Precio Energía [Eur/kW -h] 0,071238
Precio M otor [Eur] 2.422,54 2.202,14
Ahorro Eur/hora [Eur] 0,0376
Am ortización Diferencia precio horas [horas] 3.094 128 días
Am ortización M otor Eff1 horas [horas] 64445 7 años
PAYBACK TIME
t [dias]
Cost [€]
Fixed Cost EFF1
Fixed Cost EFF2
243
hCost
hCost
hkW
hkW
CostFixedCost
75.32071238.014.2202
22.32071238.054.2422
€
In 243 days the over cost of
220,4 € is amortized
2422,54 € -2202,14 € =220,4 €
http://www.motors-electrics.com/en/
30. MOTOR OPTIMIZATION
W. Deprez et al., "Iso efficiency contours as a concept to characterize variable speed drive efficiency," The XIX International Conference on Electrical
Machines - ICEM 2010, Rome, 2010, pp. 1-6.
doi: 10.1109/ICELMACH.2010.5607991
31. MOTOR OPTIMIZATION
Stator Joule losses
1.- Increase cupper
2.- Increase slot dimensions
3.- Decrease end windings
4.- Two layer winding
Iron losses
1.- Improve magnetic steel
2.- Thinner magnetic steel
3.- Improve winding factor
4.- Increase airgap
Rotor Joule losses
1.- Increase flux density in airgap
2.- Increase bar dimensions
3.- Increase bar conductivity
32. MOTOR OPTIMIZATION
Friction and windage losses
1.- Increase fan efficiency
2.- Low losses bearings
Stray load losses PSLL(additional losses)
1.- Improve winding factor
2.- Skew
33. Example.
Load with constant torque.
P2= 15 kW->n= 2600 rev/min
Minimum speed= 867 rev/min
Maximum speed= 2600 rev/min
NmT 55
60
2
2600
15000
4-poles motor Δ/Y 230/400
The maximum voltage supply is 380/400 V
Connected in Y, constant flux at 230V/50 Hz
The maximum and minimum supply frequency is:
Hzf
Hzf
p
f
n
67.86
60
22600
9.28
60
2867
60
max
min
MOTOR SIZING WITHOUT AUXILIAR VENTILATION
“AEG Manual técnico de diseño. Motores asíncronos alimentados con convertidor de frecuencia”
36. Synchronous-type electric motor drives, PMSM’s, are now extensively used in
many industrial applications requiring high system reliability and high efficiency
PERMANENT MAGNET SYNCHRONOUS MACHINES
37. Size comparison between a PMSM and an IM of the same power
PERMANENT MAGNET SYNCHRONOUS MACHINES
38. There are several different magnet materials that are commonly used. Ferrite is an
inexpensive but less magnetically powerful material that is frequently used. The
rare earth magnets neodymium-iron-boron (NdFeB) and samarium-cobalt
(SmCo) magnets are stronger magnetically and more resistant to temperature.
The PMSM is superior to induction machines both in torque per kilograms and
efficiency. Typical applications for these machines are applications where machine
volume or efficiency is important.
There are different approaches of incorporating the magnets into the rotor design:
Surface mounted magnets (SPMSM)
Interior magnets (IPMSM)
PERMANENT MAGNET SYNCHRONOUS MACHINES
39. A SPMSM is a non-salient machine because the magnet has the permeability
similar to air.
IPMSM is a salient pole machine because the iron and magnet parts of the rotor
have different permeability. Having saliency in the machine allows the utilization of
the reluctance torque instead of only the electro magnetic torque. Disadvantage:
Introduction of cogging torque due to the saliency and magnets of the rotor.
SPMSM
IPMSM
PERMANENT MAGNET SYNCHRONOUS MACHINES