Get documents about "How to Use New Motor Design Methods and Materials
Document Sample
Electrical Machines – the
future ,,,,MOVES →
Alan Jack
University of Newcastle upon Tyne
Newcastle Drives and M achines Group
This is Newcastle – it was the largest coal port in
the world in the 18th century
Hence the saying “never bring coals to Newcastle”
WEMPEC tops betting list for best machines group
worldwide so I bring machines to WEMPEC with
considerable fear and humility!
Newcastle Drives and M achines Group
The need to make things move has
never been greater
Cars
Trains
Boats
Aeroplanes
Automate
everything – 150 Alstom/Rolls Royce
motors in a mermaid pod 19MW direct
Hitachi HEV motor
drive induction motor
Mercedes S Class
Newcastle Drives and M achines Group
The old guard
Wound rotor synchronous – still the best
for big generators
Induction motors, turn it on and forget it –
still the best for 1500 to 3000 rpm fixed
speed
Commutator m/c’s dc and universal still the
cheapest for short term high speed and
low cost high starting torque
These machines won’t disappear but their
designers are a dying breed – if the
industry does not pay to train them …..
“Houston we have a problem….”
Newcastle Drives and M achines Group
Two big new drivers
1 Power Electronics
Can choose any speed – faster or slower
“synchronous” (including e.g. SRM’s) motors
possible
Can have variable speed
Can have better control
Can manage inrush – no 4pu online start
current
Can control through faults
But why does it cost so much!
Newcastle Drives and M achines Group
Magnets
Chinese magnets have removed the
cost floor
Magnets compete best at “small”
sizes but “small” is really quite large
e.g. even a turbogenerator field
magnet would “only” need to be 500
mm thick
Newcastle Drives and M achines Group
Example: Panasonic air conditioner scroll pump motor
The application is driven by
the need for efficiency
Non-overlapped, interior
magnet m/c with full inverter
Used to be the province of
on/off induction motors
Newcastle Drives and M achines Group
Smaller, lighter, cheaper
If its power we want then go faster –
or is direct drive the answer?
Push up the loadings – more flux,
more current
Find ways to make it for less
Newcastle Drives and M achines Group
Lets provide a reference - Turbogenerators
try very hard with cooling and speed
Drax 660MW- 2 pole
Built by C.A. Parsons
(inventor of steam turbine)
August 22nd 1966 – sweet 16
– those were the days!
Mag shear stress = 146 kN/m2
Rotor surface speed = 179.5 m/s = 402 mph
Self hoop stress = 253 MPa (UTS ~ 1000MPa)
Newcastle Drives and M achines Group
The biggest bang for the buck
1: how fast should we go?
50Hz is only right for 100’s of MW
everything smaller should run at higher
frequency
Motor size proportional to torque, power =
torque x speed there is a good argument
for fast
e.g. 30mm dia rotor (hand drill) for
253MPa self stress means speed of
114,000rpm = times 6 on current power!
Newcastle Drives and M achines Group
Conventional 35,000 rpm
universal motor stator
Dyson
100,000 rpm
vacuum cleaner
motor
SR motor
Newcastle Drives and M achines Group
100,000 rpm appliance motor
Mag shear stress
30kN/m2
Rotor surface speed
52.4m/sec
Self hoop stress
21.5MPa
Original motor
20,000 rpm New motor
Newcastle Drives and M achines Group
Aeroengine fuel pump 15,000 rpm,
16 kW, runs fuel flooded
Mag shear stress = 45 kN/m2
Rotor surface speed = 37 m/sec
Self hoop stress = 9.4 MPa
Newcastle Drives and M achines Group
Aeroengine
fuel pump
30,000 rpm,
100kW, runs
fuel flooded
Rotor OD 72.4mm, length 81mm, Torque = 31.8N
Mag shear stress = 54 kN/m2
Rotor surface speed = 106 m/sec
Self hoop stress = 96 MPa
Newcastle Drives and M achines Group
Turbogenset high speed generator
Typical configuration
30,000 rpm
8 poles
2kHz base frequency
Newcastle Drives and M achines Group
Lots of applications don’t want to go fast
– lets drop the gearbox – direct drive…….
translator
stator
Archimedes Wave Swing
Electric Power
Processing
TU Delft
This is going to hurt! Only 2.2MW from all that!
Newcastle Drives and M achines Group
Peak power 2.2MW, Peak force = 106 N
Mag shear stress = 179 kN/m2
Magnets
Newcastle Drives and M achines Group
Enercon wind
generator
4MW very slow =
very big!
Newcastle Drives and M achines Group
The biggest bang for the buck 2
– can we do anything about the loadings
Bn = limited by steel (and magnets) to 1T
1: drop the steel and the magnets, use
superconductors – 4T now possible but
it costs in £ and complexity
“conventional wound field synchronous
m/c” - Superconducting field, no iron in
flux path, air gap winding, forced cooled
– e.g. water
Newcastle Drives and M achines Group
Automation and Drives
Three Siemens Projects Develop the HTS-Technology
towards Drive Systems Market Requirements
1 Introduction
2 Challenges and
Trends
3 Innovative
Drive
Concepts
HTS I HTS II
HTS III
Model-Motor 4-MVA-Geno
application
4 Summary 1999-2002 2002-2005 2005-2008
P/S kW / kVA 400 4000
t
ye
U V 400 6600
d
he
lis
f Hz 50 / VSD 60 / VSD
ub
tp
n 1/min 1500 3600
No
M kNm 2,4 10,6
IEE PEMD Conference, Dublin 6th – 8th April 2006 RMO 20/ 48
Automation and Drives
HTS Machines: Small Sizes and low Weight
1 Introduction
4 MVA HTS Generator compared to conventional
generator
2 Challenges and
Trends
11 t
2700
3 Innovative
Drive
Concepts
7t
4 Summary
1800
2600 2200
3700 1900
IEE PEMD Conference, Dublin 6th – 8th April 2006 RMO 21/ 48
Automation and Drives
HTS Machines: Low Losses, High Efficiency
Loss Comparison 1FJ4 801-4 / HTS II
1 Introduction 6600 V, 60 Hz, 4000 kVA, cosphi=0,8
140000
2 Challenges and
Trends 120000 P Zus
P Cu2 / P Kry2
P Cu1
100000 P Fe
3 Innovative PR
Losses (W)
Drive 80000
Concepts
60000
40000
4 Summary
20000
0
1FJ4 801 HTS II
η (cosϕ = 0,8) 96,1 % 98,4 %
η (cosϕ = 1,0) 97,0 % 98,7 %
IEE PEMD Conference, Dublin 6th – 8th April 2006 RMO 22/ 48
2: drop the steel and
use loads of magnets
Bn still 1T using halbach magnets
- but big weight and volume
reduction
Direct drive ironless wheel motor –
Mecrow et al
5Nm/kg naturally cooled
Low inductance
– keeps down converter VA
– field weakening limited
Newcastle Drives and M achines Group
3: Modulated pole machines –
TFM, Claw Pole Claw Pole structure
All poles see all of the mmf –
SMC Core Back
Coil
electric loading proportional Magnets
to pole number
SMC Rotor
Shaft & Hub
Newcastle Drives and M achines Group
Claw pole TFM
23Nm/kg, naturally cooled, 100 poles, power factor 0.41
very high electric loading, tortuous magnetic path
= the flux leaks all over the place
= poor power factor and bad use of magnets
Mag shear stress = 68kN/m2
Newcastle Drives and M achines Group
There is nothing much in electrical
machines which is truly new!
Alexanderson Looks a bit like
-Fessenden a double sided
inductor TFM to me!
alternator
circa 1910
Newcastle Drives and M achines Group
Making it cheaper - should we compromise the
motor for the electronics?
Is it 6 switch bridge
or matrix converter
for everything?
Or should we bifilar
wind for instance?
Newcastle Drives and M achines Group
PM machines – “new” freedoms
Magnet strength prop depth; winding
strength with area - at small sizes magnet
has massive advantage
Magnets don’t conduct (much!)
Magnets are not permeable
Magnets have fixed pole number
Can take terrible liberties with magnetic
and electric circuit!
Newcastle Drives and M achines Group
Explosion in methods of
construction - Its all about non-
overlapped coils
Non-overlapped coils let you tear the
motor apart
Make the end windings shorter
Allow slots to be fully filled even with
full automation (coil insertion slot fill
<35%, separate teeth 65% or more)
But have lots of space harmonics so
watch out!
Newcastle Drives and M achines Group
Single Tooth Segment Approach to
Machine Construction (Sheldon 1954)
Newcastle Drives and M achines Group
Panasonic servo motors
Newcastle Drives and M achines Group
SMC servo motor
Mag shear stress = 28 kN/m2
Newcastle Drives and M achines Group
IEE PEMD 2004
Two part
Three part
Cutting down the no of parts
to keep the cost down
Newcastle Drives and M achines Group
Mitsubishi joint-lapped core
Core segments are clenched Core is hinged back
together to for pivots to get access
Newcastle Drives and M achines Group
Further Core Splitting
Techniques
Yaskowa separate
tooth and core backs
Plastic over-
moulding provides
bearing mountings
– i.e. has no metal
case
Newcastle Drives and M achines Group
Slip on coils over the core back
Newcastle Drives and M achines Group
Little men laminations
Coil slips onto teeth
Newcastle Drives and M achines Group
Axial flux motors are difficult to
laminate - real opportunity for SMC
SMC + Laminations
“strip” core back “rolled
up” holds teeth Newcastle Drives and M achines Group
What’s new in SR’s segmented rotor
Conventional 12/8 SR = 22.5Nm
Segmented 12/10 SR = 32Nm
Mag shear stress 22 kN/m2
PM 12/8 = 42Nm
Newcastle Drives and M achines Group
What’s new in SR’s 2: – flux switching - Black
and Decker Circular saw motor – Pollock et al
x x
x - - x
-
-
- -
-
x x -
x x
Implemented circuit – natural “series
wound” characteristic
Cheaper bifilar circuit
Newcastle Drives and M achines Group
Non-overlapped winding induction motor
can we get I2R reduction?
Shorter end windings,
better slot fill
But nonsynchronous
harmonics cause loss
(evens really hurt)
Two stators displaced
180o wound backwards
kills even harmonics
But! zig-zag is very
high
Mk 2 with tooth splits
Newcastle Drives and M achines Group
Tooth splits
No load – mag
8 current
Conventional up slightly
MK 1 non-overlapped
Mk 2 non-overlapped
Torque (Nm)
6
4
2
0
0 500 1000 1500
rpm
Rotor current driven field -
Still some work to do!
Still lots of zig-zag Drives and M achines Group
Newcastle
Linear actuators
piston pumps
Free piston engines
Linear servos and position
smc
Newcastle Drives and M achines Group
To Conclude:
If electronics cost next to nothing (big if!!!):
IM looses all round
SRM might win some
PM wins (if magnets keep falling in price!)
The biggest motor challenge bar
none is to get the cost of the
electronics down
Newcastle Drives and M achines Group
Related docs
