Matrix Technology for next generationMatrix Technology for next generationMatrix Technology for next generation Variable Speed

Electric Motor Control

Matrix Technology for next generation Variable Speed

Electric Motor Control

First….Why do we need variable speed control of electric motors?speed control of electric motors?

Soft starting of electric motorSoft starting of electric motor

Multiple starts and stops without limit

Adapting driven load to capacity demands of the processprocess

Energy SavingsEnergy Savings

Flow, Speed (RPM), Torque & Power

Flow - Torque - Output Power

9095

100

Affinity Laws

5560657075808590

…...

50% RPM = 50% Flow80% RPM = 80% Flow

1520253035404550

% o

f …

50% RPM = 25% Torque80% RPM = 64% Torque

80% RPM = 80% Flow

05

1015

0% 10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Speed (RPM)

50% RPM = 12.5% Power80% RPM = 51 2% Power

80% RPM = 64% Torque

Speed (RPM)

Flow Rate Torque (Pressure) Output Power

80% RPM = 51.2% Power

Pumps & PowerThrottle Valve vs VFDThrottle Valve vs VFD

100110

60708090

Con

sum

ed

2030405060

% E

nerg

y C

01020

40 45 50 55 60 65 70 75 80 85 90 95 100

% Flow Rate

Throttle Valve VFD

Key Issues for Specifying Variable Speed Motor Controllers

Upstream effects to power gridDownstream effects to electric motor, thus motor reliabilityController reliabilityController Size weight costController Size, weight, costController efficiencyControl room infrastructure costsAffect on motor costTorque and Speed control performance of electric motor for the specific applicationmotor for the specific application

Affects of Traditional VFDs in the System –Fluid Analogy

Picture a 10 inch pipe containing water at 4160 PSIGate valve operates in the center of the pipe opening and closing at 1000 times per secondWater hammer travels in both directions from the valve

Downstream effectsUpstream effects

Affects of Traditional VFDs in the System

A VFD in the electrical supply system acts like the valve, creating disturbances upstream and downstreamThe VFD switches at up to 15,000 times per second!Instead of pressure and flow, affects are on voltage and current

Upstream Affects Downstream Affects

VFDVFD

Upstream Affects of Input Voltage and Current Waveform Distortion?

Reduced power factor-circulating currents that t l t i l t it b t d ktax electrical system capacity, but do no work(Those who do not maintain good power factor build cogen plants and buy larger generators)

Adverse affects on transformers, conductors, circuit breakers, and generatorsHi h h ti l i d liHigher heating losses in power delivery equipment Spurious CB and fuse tripsSpurious CB and fuse trips

Why be Concerned About Voltage andWhy be Concerned About Voltage and Current Waveform Distortion?

Inefficient use of available capacity from the utility grid will limit plant expansion or force development of expensive cogeneration capacityGenerators have high impedance and can loseGenerators have high impedance and can lose regulation due to the harmonic voltage drop across the stator. In addition, the excess heating in the windings can force derating of the generator, and in severe g g ,conditions can trip the generatorWhen generators are used as back up power supplies, the effect of the harmonic content in the electrical di t ib tio te t be l ed both de o ldistribution system must be analyzed both under normal utility power and under standby generator power. Typical generators will have 15% to 20% internal reactive impedance, whereas utility transformers will p , ytypically have between 2% to 5% internal reactive impedance

Downstream Affects-Bearings

The output of the traditional 2 level voltage source PWM type VFD causes a voltage

potential to build on the shaft of the AC motorpotential to build on the shaft of the AC motor

Arcing occurs that will pit the bearing races asArcing occurs that will pit the bearing races as this voltage seeks groundMotors with electrically isolated bearings h ld b ifi dshould be specified

Brush rig shaft ground kit is alternate solution

Downstream Affects-Bearings

Downstream Affects-Voltage Stress on Motor Insulation Caused

by High dv/dt

Present VFD technology poses a documented th t t t i l ti lifthreat to motor insulation lifeEach VFD output pulse results in a voltage spike potentially as high as 3 times nominal motorpotentially as high as 3 times nominal motor voltageAC motors must have a sufficiently high Corona I ti V lt (CIV) t i lt ikInception Voltage (CIV) to survive voltage spikes (dv/dt)Special motor designs (inverter duty)Special motor designs (inverter duty)

Downstream AffectsDownstream AffectsVoltage Stress on Motor Insulation

Downstream Affectso st ea ects3 level low voltage inverter = ½ dv/dt

Ｐ

V０VPN

Ｎ

Downstream AffectsDownstream AffectsDownstream AffectsReduction of dv/dt levels on the outputDownstream AffectsReduction of dv/dt levels on the output

Output Voltage WaveformsMulti-level control eliminates motor surge voltage issue

2-Level Inverter

g g(Reflected Wave Phenomenon)

The output waveform is nearly sinusoidal.

Multi-level Inverter

sinusoidal.

■ No surge voltage to negatively affectthe motor■ Low torque ripple - good for load Inverter

Matrix 4.16kV output waveform.

■ Low torque ripple - good for load■ Audible noise as low as commercial power supply operation■Existing motors and motor cables can be usedbe used

Present Medium Voltage (MV) Inverters begin toPresent Medium Voltage (MV) Inverters begin toPresent Medium Voltage (MV) Inverters begin to solve Downstream AffectsPresent Medium Voltage (MV) Inverters begin to solve Downstream Affects

M di V lt Di t ib ti RMedium Voltage Distribution Range2.4 to13.8kV3 3 6 6 and 13 8kV class are common standards3.3, 6.6, and 13.8kV class are common standards4.16kV dominant in US, some 2.4kV in US and Canada

Traditional Medium Voltage Inverter TypesTraditional Medium Voltage Inverter TypesCurrent Source (CSI) – Rockwell Power Flex 7000 (ca late 70s)3 Level Voltage Source (VSI) - ABB ACS1000 (ca early 90s)5 Level VSI – ABB ACS5000, Toshiba T300MV (ca mid 90s)Multi level VSI – Yaskawa MV1S, Siemens Robicon Perfect

Harmony others (ca mid 90s)Harmony, others (ca mid 90s)

Traditional VFD (Voltage Source Type)The inverter changes AC power to DC power and thenThe inverter changes AC power to DC power and thenThe inverter changes AC power to DC power and then The inverter changes AC power to DC power and then changes it back to AC powerchanges it back to AC power

CCACAC ACACDCDC

Harmonic Distortion-the Unsolved Upstream AffectUnsolved Upstream Affect

Fourier Analysis of the waveforms

Three phase diode rectifier, line voltage/current

600700

Fourier Analysis of the waveforms found in a three phase diode rectifier shows low order harmonics including the 5th, 7th, 0

100200300400500

harmonics including the 5th, 7th, 11th, 13th, etc.

Calculation of true power factor -700-600-500-400-300-200-100

Voltage CurrentCalculation of true power factor considers the energies contained on these additional frequencies. Figure 6-2 shows the resulting

-700Figure 18.1

100.00%

amen

tal

Normalized Harmonic Spectrum

Figure 6 2 shows the resulting harmonic spectrum based on Fourier analysis of the current waveform shown in figure 6-1. 30.38%

agn

itu

de (

as %

of

Fun

da

g5.55% 7.16% 4.83% 4.32% 3.59%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Harmonic Order

Ma

Figure 18.2

How Harmonics L Effi i

True power factor is greatly affected by THD. Consider VFD below with no filters.

Lower EfficiencyTrue power factor is improved, when current distortion is corrected (includingCo s de e o o e s

400

500

current distortion is corrected (including filters or active switching front ends)

400

500

-300

-200

-100

0

100

200

300

400

-300

-200

-100

0

100

200

300

-500

-400

Figure 19.1

pf = kW/kVA

Power Factor Considering 92.8% I THD

-500

-400

Figure 19.1

Power Factor Considering 52.6% I THD

pf = kW/kVA

I THD = 92.8%

pf = 1/Sqrt(12+.9282)

pf = kW/kVA

I THD = 52.6%

pf = 1/Sqrt(12+.5262)pf = 73.3%

Figure 19.2

pf = 88.5%Figure 19.2

■ Generates variable AC voltage and frequency directly from AC power supply

What is a Matrix Converter?■ Generates variable AC voltage and frequency directly from AC power supply■ AC-AC direct conversion without DC link■ Energy saving (low switching losses), Long product life, Space saving

Detail of bi-directional switchNo DC bus capacitor

Matrix Converter(Single cell) S1

S2S3

MotorMotorBi-directionalsemiconductorswitching device

S4

Power Power SourceSource

S5S6

Motoring PowerMotoring PowerRegenerative Power

One Bidirectional Cell 635V

Configuration of the Medium Voltage MatrixConfiguration of the Medium Voltage MatrixConfiguration of the Medium Voltage Matrix Power CellsConfiguration of the Medium Voltage Matrix Power Cells

Configuration of MxC power cell section(4.16kV class: 4 cells in series for each phase)

Configuration of an Matrix power cell

(Bi-directional IGBT switch)

O t t( p )

UU Input Output

U1

U2

U3

U4

2402VPhase Voltage 4160V4160V

LineLineVoltageVoltage

W4W3

W2

V4V3

V2

Multi-level control is the optimum configuration for existing AC motorsW1 V1

WW VVo e st g C oto s

Configuration of a Medium Voltage MatrixConfiguration of a Medium Voltage MatrixConfiguration of a Medium Voltage Matrix ConverterConfiguration of a Medium Voltage Matrix ConverterThe Matrix uses PWM control

N

W4

U4V4

MxCCELL MxC

CELLM C

The Matrix uses PWM control with multiple outputs connected in series, using 4 MxC cells per phase (for 4.16kV).

Main circuitCell control

MxCCELL

AC 4.16kVW3

U3V3

Controller

MxCCELL MxC

MxCCELL

circuit(Fiber optic) Input

(Primary) W2

U2

U1

V2

CELLMxCCELL MxC

CELL MxCCELL

MxC Cell

UV

W

W1

U1V1

MxCCELL

CELL

MxCCELL

MxCCELL

Output(Secondary)

U WM

Panel Configuration - 4.16kV 1250HPPanel Configuration - 4.16kV 1250HP

Transformer- Dry type, multiple winding with high reliability Class H insulation

Control section

Power CellsNo DC Link capacitors

Class H insulation

Power cell section

- No DC Link capacitors- Modular, draw out type for simple replacement- Easy access for circuit board and fuse

Transformer sectionControl-Visible arrangement-Low voltage-High reliability PCB

Solution for Upstream AffectsSolution for Upstream AffectsSolution for Upstream AffectsMinimal Input Harmonics Solution for Upstream AffectsMinimal Input Harmonics

Input Current WaveformsMulti-level control virtually eliminates input harmonics

6-pulserectifier

Compliant with International Standards for Power Quality

No harmonics filt ti filtfilter or active filter

is requiredMatrix

Solution for Downstream AffectsSolution for Downstream AffectsSolution for Downstream AffectsSinusoidal Output VoltageSolution for Downstream AffectsSinusoidal Output Voltage

The output waveform is nearly

Output Voltage Waveforms

The output waveform is nearly sinusoidal.

Multi-level control eliminates

2-Level Inverter

motor surge voltage issue (Reflected Wave Phenomenon)Low torque ripple - good for load.

Multi-level I

Audible noise as low as commercial power supply operation

Inverter

Matrix output waveform.

Existing AC motors and motor

cables can becables can be used

M t i C tUpstream effects to power gridDownstream effects to electric motor, thus motor reliabilityController reliabilityMatrix Converter

How does it solve the

Controller reliabilityController Size, weight, costController efficiencyControl room infrastructure costsAffect on motor costTorque and Speed control performance of electric

issues?Minimal Input and Output harmonics – No filters required

Torque and Speed control performance of electric motor for the specific application

Power factor at input is .97+ regardless of buss characteristics thus efficient use of supplied power

13 level output waveform at 3 3kV and 26 level at 6 6 kV13 level output waveform at 3.3kV and 26 level at 6.6 kV, thus close to sinusoidal output

Converts input AC to output AC without a DC bus, thus no capacitors-this vastly improves reliability and reduces size

Improved Efficiency over existing designs; from 94 to 97+%. With thermal losses cut in half and with smaller physicalWith thermal losses cut in half and with smaller physical footprint, there is less cost impact on control room HVAC

Upstream effects to power gridDownstream effects to electric motor, thus motor reliabilityController reliabilityMatrix Converter

How does it solve the

Controller reliabilityController Size, weight, costController efficiencyControl room infrastructure costsAffect on motor costTorque and Speed control performance of

issues?

Special motors not required; can be applied to existing

Torque and Speed control performance of electric motor for the specific application

motors (and cables) without addition of filtersFully regenerative to power line-full control of electric motor

in all four quadrants of operation without dynamicin all four quadrants of operation, without dynamic braking circuitry

Precise torque control, even at zero speed without derating gof the duty cycle of the power transistors

Control of motor in velocity or torque mode

Matrix, the perfect electric valve?

Matrix Architecture represents transformational technology, a long awaited advance in motor control design that enables complete control ofcontrol design that enables complete control of electric motor speed and torque performance, without mistreating the power grid or the electric motor.

As such when total cost of the motor controlAs such, when total cost of the motor control system is considered, Matrix technology will become the dominant design moving forward.

Thank you from Yaskawa and Atlas Copco JC CarterAtlas Copco JC Carter

Yaskawa Electric Corporation

Founded: 1915Sales: $4.0 billionAssociates: 8,000Headquarters: KitakyushuKitakyushu, Fukuoka, Japan

Worldwide Locations

JapanJapanYukuhashiYukuhashi

K kK kUnited StatesUnited StatesTorsasTorsas

UKUK

SwedenSwedenCanadaCanadaTorontoToronto

KokuraKokuraYahataYahataIrumaIrumaWest West

CarrolltonCarrolltonChicagoChicago

United StatesUnited States

SchwalbachSchwalbachGlasgowGlasgow GermanyGermany

TroyTroy

New BerlinNew Berlin

IsraelIsrael

ChinaChinaBeijing Beijing ShanghaiShanghai

Tel AvivTel AvivTroyTroyPortlandPortlandColumbusColumbus

ShanghaiShanghai

Kuala LumpurKuala LumpurMalaysiaMalaysia

BrazilBrazil

Kuala LumpurKuala Lumpur

Sao PauloSao Paulo~~Sao PauloSao Paulo

YEC – Yaskawa Electric Corp. - JapanEstablished in 19151930 – 40’s – Motors & Controllers1950’s – Motors / Applications1960’s – Industrial Electronics1970’s – Industrial Automation1980’s to Present – Factory Automation & Mechatronics4 Billion Dollars in sales worldwide4 Billion Dollars in sales worldwideWorlds Largest AC Drive Manufacturer

Power Quality Topics

What are Harmonics?What is Harmonic Distortion?What is Harmonic Distortion?Differences between current and voltage distortionvoltage distortionPossible effects of HarmonicsWhat Guidance is there in theHarmonics are important to understand theWhat Guidance is there in the IndustryWhat Solutions does Yaskawa Offer?

Harmonics are important to understand the relationship between Power Quality and switch mode power supplies!

What Solutions does Yaskawa Offer?

D fi iti f H iDefinition of HarmonicsHarmonics are defined as currents or voltages with frequencies that are integervoltages with frequencies that are integer multiples of the fundamental power frequencySIMPLY PUT - Harmonics are used to mathematically describe the shape of a curve that is not sinusoidalcurve that is not sinusoidal.

What is Harmonic Distortion?What is Harmonic Distortion?Harmonic Distortion is a mathematical way of describing how non-sinusoidal a wave shape appearsFourier Analysis - Sum of the Squares

TVD Vh=∞

∑ 2

THD = 78.3%

hh z=∑

THD = 1.2%

Every Wave shape has Harmonic Distortion!

Types of HarmonicsDC Drive - SCR Based AC Drive - Diode Rectifier

SCR Rectification - Line Notching, Increases Voltage Distortion

Diode Rectification - Pulsed Current, Increases Current Distortion

New Technology May Solve Old Power Quality Problems

Possible Effects of HarmonicsIncreased Transformer Heating

d d K F t f 4 t 13recommended K-Factor of 4 to 13 on new installations

I d C d t H tiIncreased Conductor Heatinglarger gauge wire

i i ll lrun two wires in parallelElectromagnetic EquipmentPLCs - more sensitive to Voltage Notching

System resonance - Power Factor C i

( )PF PF Power Power Power PowerTrue Total al al act Harmonics= = + +Re Re Re ./

Correction utilize input reactors to reduce likelihood

f

Harmonic Distortion most likely will have no effect on Power Distribution Performance

How Harmonics L Effi i

Consider estimating power factor at the terminals of an AC Drive in a system with

Lower EfficiencyTrue power factor is improved, when current distortion is limited by system

low source impedance (high available short circuit current) with no input line reactor or DC bus choke.

400

500

current distortion is limited by system impedance. (Including reactors, or bus chokes.)

400

500

-300

-200

-100

0

100

200

300

400

-300

-200

-100

0

100

200

300

-500

-400

Figure 39.1

pf = kW/kVA

Power Factor Considering 92.8% I THD

-500

-400

Figure 39.1

Power Factor Considering 32.6% I THD

pf = kW/kVA

I THD = 92.8%

pf = 1/Sqrt(12+.9282)

pf = kW/kVA

I THD = 32.6%

pf = 1/Sqrt(12+.3262)pf = 73.3%

Figure 39.2

pf = 95.08!Figure 39.2

Power Factor When Harmonics ExistHarmonics Exist

From IEEE Std. 141-1993: Power is the product of in-phase current times the voltage or:

P = V * I cos θ

True Power Factor Representation - Expanded

ctiv

e

r)P60 = V60 * I60cos θIn the case of harmonics:

Ph = Vh * Ihcos θ or S = (Sqrt(P2 + Q2

+D2)){R1]

QRe

acPo

wer

X

(kVA

r

))

Where P = Real Power, Q = Reactive Power and D = Distortion Power.

P Real Power (kW)

Figure 40 1

System losses will be higher due to the harmonic components than with

Figure 40.1

components, than with equivalent 60 kVA.

Ph = I2h * Rh

The Risk of Parallel RResonance

Hp - the harmonic order (per-unit frequency) at parallel resonant frequency

Power Factor Capacitors Relieve Load [R2]

q y) p q yMVAsc - the system short-circuit capacityMVArc - the power factor improvement capacitor

XcXL

i

ih

Hp - Sqrt(MVAsc / MVArc)

Per IEEE Red Book (Std 141 1993): “If

ih

Resonance occurs when: Xc = XLFigure 41.1

Per IEEE Red Book (Std. 141-1993): If the SCR (short circuit ratio is less than 20), and there is a parallel resonance condition near a characteristic harmonic of the non linear load there will be a

Parallel Resonance

of the non-linear load, there will be a problem.”

Since all power systems have inductance and capacitance, they will resonate at a given frequency. When an exciting energy at that frequency, in a quantity that is large enough to offset the natural

Current measured at the capacitor,showing 660Hz, (11th harmonic resonance)Figure 41.2

of Harmonic Mitigation Devices

Assumptions:10,000 installed

Figure 42.2base cost of 6-pulse drive.Values will vary for lower HP drives.

MTBF Ratingsg

Calculating MTBF:Calculating MTBF:Total Hours of Operation = 3,128,068 = 1,564,034 Hrs

Number of failures 2

To put this in terms of years instead of hours,To put this in terms of years instead of hours,divide by 8760 hours/year:divide by 8760 hours/year:

MTBF=MTBF= 1,564,0341,564,034 1781788,7608,760

~~==Interpretation: if you had 178 drives running Interpretation: if you had 178 drives running

24/7, you could expect one failure per year!24/7, you could expect one failure per year!

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