yaskawa ac drive gt 1

1

ＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡ

YASKAWA INVERTER


THANK YOU

For further information please contact usFor further information please contact us

2


Market of General purpose InvertersMarket of General purpose Inverters

IntroductionIntroduction


4

109109109109 127127127127 144144144144 151151151151 166166166166

120120120120109109109109118118118118

9898989893939393

840

751767715644

0000

50505050

100100100100

150150150150

200200200200

250250250250

300300300300

350350350350

2002200220022002 2003200320032003 2004200420042004 2005200520052005 2006200620062006 2007200720072007 2008200820082008

00001001001001002002002002003003003003004004004004005005005005006006006006007007007007008008008008009009009009001000100010001000

202225

262 260

Drives Industry Market Growth in JapanDrives Industry Market Growth in Japan

Hu

nd

red

millio

n ye

nUn

its

x1

0,0

00

Drives up to 75 kW

Hundred million

Tens of thousands

Export

Domestic

23% 24%

27% 26%

3%

51%

15%

31%

up to 0.75 kW

0.75 kW to 4 kW

4 kW to 15 kW

15 kW to 75 kW

Units Amount

Shipments by capacity in 2008

Data from JEMA

286

3


5

TotalTotalTotalTotalTotalTotalTotalTotal1.813million1.813million1.813million1.813million1.813million1.813million1.813million1.813million

FujiFujiFujiFujiFujiFujiFujiFuji24.3%24.3%24.3%24.3%24.3%24.3%24.3%24.3%

MitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishi30.5%30.5%30.5%30.5%30.5%30.5%30.5%30.5%

ToshibaToshibaToshibaToshibaToshibaToshibaToshibaToshiba9.5%9.5%9.5%9.5%9.5%9.5%9.5%9.5%

HitachiHitachiHitachiHitachiHitachiHitachiHitachiHitachi5.9%5.9%5.9%5.9%5.9%5.9%5.9%5.9%

OthersOthersOthersOthersOthersOthersOthersOthers6.0%6.0%6.0%6.0%6.0%6.0%6.0%6.0%

TotalTotalTotalTotalTotalTotalTotalTotal2,342M US$2,342M US$2,342M US$2,342M US$2,342M US$2,342M US$2,342M US$2,342M US$

YaskawaYaskawaYaskawaYaskawaYaskawaYaskawaYaskawaYaskawa12.8%12.8%12.8%12.8%12.8%12.8%12.8%12.8%

FujiFujiFujiFujiFujiFujiFujiFuji9.6%9.6%9.6%9.6%9.6%9.6%9.6%9.6%

MitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishiMitsubishi9.8%9.8%9.8%9.8%9.8%9.8%9.8%9.8%

OthersOthersOthersOthersOthersOthersOthersOthers25.8%25.8%25.8%25.8%25.8%25.8%25.8%25.8%

WorldWorld

YaskawaYaskawaYaskawaYaskawaYaskawaYaskawaYaskawaYaskawa23.7%23.7%23.7%23.7%23.7%23.7%23.7%23.7%

ABBABBABBABBABBABBABBABB10.0%10.0%10.0%10.0%10.0%10.0%10.0%10.0%

Rockwell Rockwell Rockwell Rockwell Rockwell Rockwell Rockwell Rockwell 12.1%12.1%12.1%12.1%12.1%12.1%12.1%12.1%

SiemensSiemensSiemensSiemensSiemensSiemensSiemensSiemens7.9%7.9%7.9%7.9%7.9%7.9%7.9%7.9%

※※※※Data estimated by Sales Promotion Section

ToshibaToshibaToshibaToshibaToshibaToshibaToshibaToshiba--------SchneiderSchneiderSchneiderSchneiderSchneiderSchneiderSchneiderSchneider7.2%7.2%7.2%7.2%7.2%7.2%7.2%7.2%

C.TC.TC.TC.TC.TC.TC.TC.T4.8%4.8%4.8%4.8%4.8%4.8%4.8%4.8%

Inverter Market Shares Inverter Market Shares (FY (FY 2009 2009 ))

JapanJapan

unitsunitsunitsunitsunitsunitsunitsunits

※※※※This share represents No. of unitsproduced in Japan.


6

Yaskawa

14.1%

A

13.0%

B

12.8%C

12.5%

D

11.4%

E

8.6%

G

2.8%

F

7.8%

H

1.7%

Others

15.2%

\ 395.9 billion

2009

17.4%

15.8%12.8%

17.0%11.0%

Japan

USAEurope

China Asia

*Data has been gathered and analyzed by Yaskawa.

No.1 Global ShareNo.1 Global Share(fiscal year 2009)

Global Share by RegionGlobal Share by Region

4


7

VS-610

VS-610B

VS-616T

Thyristor inverter (current type)

Thyristor inverter (current type)

PWM transistor inverter (analog)

Varispeed G7

Varispeed A1000

VS mini V1000

VS mini J1000

World’s

First

World’s

First

1000th1000th GenerationGeneration

＊＊＊＊ 3-level

World’s

First

Year of 1968

1974

1980

VS-616HⅡⅡⅡⅡ PWM transistor inverter (digital)

1984

VS-616GⅡⅡⅡⅡ, GⅡⅡⅡⅡLN PWM transistor inverter (IGBT, low-noise type)

1987

3rd Generation

VS-616G3, etc.PWM transistor inverter

1989

5th Generation

VS-616G5, etc.PWM transistor inverter

1995

1969

World’s

First

VS-616G, H PWM transistor inverter (analog)

Year of 2000

2009

2008

2008

Year of 2000 to 2010

History of Yaskawa GeneralHistory of Yaskawa General--purpose Inverterspurpose Inverters


8

RELIABILITY OF THE YASKAWA INVERTER

Yaskawa Japan produced the inverter unit about 60,000 units per month. We made the

follow up record from field trouble for every month.

The calculation is base on “Fit” unit. (where; 1Fit = 10-9Hrs.)

For the Yaskawa Inverter ,the reliability target is 250 Fit and has been achieved the target.

Example of Reliability; (Some customer adopt 100 units in their factory which operated 8000 Hrs/Yr.)

The reliability result =100 units*250Fit*8000Hrs(1yr Operating Hrs)

(base on 100 units)

=102units*250*10-9*8*103

= 0.2 unit/Yr

= 1units/5Yrs.

5


9

Inverter Principle and CharacteristicsInverter Principle and Characteristics


What’s a drive?What’s a drive?

AC voltageRectifier Circuit (converter section

changing AC to DC)

DC Bus (capacitors smooth out the waveform)

Inverter Circuit (inverter section changes DC back

into AC)AC voltage

Control circuit section

Constant

frequency,

constant

voltage

Variable frequency, variable voltage

Motor

Basic Circuitry in an Inverter Drive

A device that converts frequency and voltageA device that converts frequency and voltage

Inverter ConfigurationInverter Configuration

6

ＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡActual Output Voltage Waveform

Basic wave

EDC

Output voltage (V) is low when frequency (f) is low.

0

0

Output voltage (V) is high when frequency (f) is high.

EDC

The waveform created in the switching patterns on the previous page is a square wave. A sine

wave, however, is more preferable for accurate motor control.

In the diagram below, IGBT switching creates the waveform, a technique called, “pulse width

modulation” (PWM). PWM is capable of creating a waveform very similar to a sine wave.

V

V


12

Control Method Output Frequency Features

PA M M ethodPA M M ethodPA M M ethodPA M M ethod (Pulse Amplitude Modulation)

・ Voltage control is

needed for the converter.

・ Motor current distortion is excessive, resulting in torque ripple.

PW M M ethodPW M M ethodPW M M ethodPW M M ethod (Sinusoidal Wave Approximate) PWM:

Pulse Width Modulation

When the above Output power frequency is 60 Hz, the number of pulses per cycle is

14. Therefore, carrier wave (carrier frequency) is obtained as 60×14 = 840 Hz.

Since the actual inverter has this carrier frequency of 15 kHz, the number of pulses

per cycle is 250 pulses (15000÷60).

・ Frequency and voltage

can be controlled only in the inverter section.

・ Smooth operation is possible at a low speed.

EdEd

(Ed: DC voltage)

Output Voltage Waveform

Ed

Ed

Average Output Voltage

VoltageVoltage--type Inverter Control Methodtype Inverter Control Method

7


13

Name Diode Thyristor GTO

(Gate Tum Off Thyristor)

Bipolar Power Transistor

IGBT (Insulated Gate Bipolar

Tr.)

Power MOS FET (Power Metal Oxide

Semiconductor. Field Effect Tr.)

Sy

mb

ol

Ch

ara

cte

ris

tic

s

Vo

ltag

e,

Cu

rre

nt

Wav

efo

rm

Fea

ture

s,

Ap

plic

ati

on

General high-voltage,

large-current rectifier

circuits

High-voltage,

large-current converter

section

Inverter section, chopper

section attached with

commutation circuit

High-voltage,

large-current inverter

section, chopper

section

Medium voltage,

medium current

high-speed switching,

inverter section

Medium voltage,

medium current

high-speed switching,

inverter section

Low-voltage, small-

current high-speed

switching, inverter

section

Main Semiconductor Power Elements Used for InvertersMain Semiconductor Power Elements Used for Inverters

Anode

Cathode Gate

Collector

BaseEmitter

Drain

Gate

Source

ＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡＹＡＳＫＡＷＡMain Circuit and Control Circuit

AC

AC

DC

IMT

Pulse train output

R

S

Voltage

CurrentVoltage

Current

Multi-function analog

output (output frequency,

current, etc.)

Fault output

Multi-function contact

output (running, speed

agree, etc.)

Multi-functioninput

Sequencecommon

Analog input (speed setting)

Pulse train input

DigitalOperator

Analogmonitor

AC

power

supply

Inp

ut

term

inals

Ou

tpu

tte

rmin

als

Rectifier circuit(diodes)

Inverter conversion

circuit (IGBTs)

FWD run

REV run

Serial communication input

Voltage

Current

Smoothing circuit or DC bus

(capacitors)

8


15

Varispeed G7

Specifications V/f Control V/f Control with PG Feedback

Open-loop Vector Control

Flux Vector Control

Basic Control

Voltage/frequency control (open-loop)

Voltage/frequency control with speed

compensation

Current vector control without PG

Current vector control with PG

Speed Detector Not needed

Needed (pulse generator)

Not neededNeeded

(pulse generator)

Option Card for Speed Detection Not needed Needed Not needed Needed

Speed Control Range 1:40 1:40 1:200 1:1000

Starting Torque 150% at 3 Hz 150% at 3 Hz 150% at 0.3 Hz 150% at 0 min-1

Speed Control Accuracy ±±±±2 to 3% ±±±±0.03% ±±±±0.2% ±±±±0.02%

Torque Limit Disabled Disabled Enabled Enabled

Torque Control Disabled Disabled Enabled Enabled

Typical Applications

Multi-drives Replacement for existing

motor of which motor constants are unknown

Auto-tuning is enabled only for line resistance.

Simplified feedback control

Applications where pulse generator is attached on the machine shaft

Any variable speed drives

Simplified servo drives

High-accuracy speed control

Torque control

Features of Control ModeFeatures of Control Mode


16

Operation CharacteristicsOperation Characteristics

9


17

(a) Proper Acceleration Time (b) Short Acceleration Time

AccelerationAcceleration

Output Frequency f

Motor speed N

Overload capacity when inverter

capacity is equal to motor capacity

Rated Current

Excessive Slip

Overload capacity when inverter

capacity is increased

Rated Current

0

0 0

0


18

Inverter Output Frequency[Dotted line shows the set

accel. ratio.]

Motor Speed

Motor Current

Accel. time becomes longer automatically.

Peak current is limited to within the specified value.

Stall Prevention during AccelerationStall Prevention during Acceleration

t

10


19

Inverter Output Frequency

Load

Stall Prevention during RunningStall Prevention during Running

To avoid overloading by rapid

fluid temperature in hydraulic

machines. Avoid overloading by

decreasing output frequency.

t


20

DC Voltage

Inverter Output Frequency

Motor Current

RUN Signal

Actual Stall Prevention FunctionActual Stall Prevention Function

Edc.

OV，OA

11


21

Inverter Output Frequency[Dotted line shows the set decel. ratio.]

Motor Speed

DC Voltage

DC bus voltage is limited to within specified value.

Decel. time becomes longer automatically.

Stall Prevention during DecelerationStall Prevention during Deceleration

t


22

t

DC Injection Braking Time

t

DC

Current

N

N

t

DC Injection BrakingStarting Frequency

N, f

DC

Current

DC Injection

Braking Time

N

FF

F

(a) Frequency Deceleration

(Example of DC

Injection Braking

Before Stop)

(b) All-area DC Injection Braking (c) Coasting to a Stop

DC Injection BrakingDC Injection Braking

0 0 0

N, f N, f

Free Run

12


23

Circuit Pattern Input Current Waveform Input Current SpectrumHarmonics

Content

No countermeasures taken

Harmonics Order

88%

AC reactor inserted

38%

DC reactor inserted

33%

P

N

P

N

P

N

+

+

+

Typical Inverter Input Current WaveformTypical Inverter Input Current Waveform

in Each Power Supply Method (1)in Each Power Supply Method (1)

1 5

1 5 7 11

1 5 7 11


24

Circuit Pattern Input Current Waveform Input Current SpectrumHarmonics Contents

12-phase rectification

Harmonics Order

12%

PWM control converter

3%

P

N

P

N

+

+

1

1

Typical Inverter Input Current WaveformTypical Inverter Input Current Waveform

in Each Power Supply Method (2)in Each Power Supply Method (2)

13


Inverter Drive Units SelectionInverter Drive Units Selection


26

Motor Type

Motor Output

Inverter Output

Inverter Model

Peripheral units, Options

Enclosure

インバータの機種選定インバータの機種選定インバータの機種選定インバータの機種選定

Check Item

What to DecideCapacity SelectionCapacity Selection

Machine specifications

Operation method

Load type and characteristics

Inverter capacity selection

Inverter model selection

Motor selection

Peripheral units, options

Investment effect

Investment effect

Inverter selection

Final specifications

14


From General IndustrialFrom General Industrial--use to Consumer Equipmentuse to Consumer Equipment

GeneralGeneral--purpose Inverter Series purpose Inverter Series

Varispeed G7

Varispeed A1000

Varispeed V1000

Varispeed J1000

High-graded Function Current Vector Control (0.4 to 300 kW)

High Performance Vector Control (0.4 to 630 kW)

Compact Vector Control Control (0.1 to 18.5 kW)

Compact V/f control Drive (0.1 to 5.5 kW)


(1) Power supply transformer

(2) Circuit breaker or

(3) Leakage breaker

(4) Contactor(6)Noise filter

(5) AC reactor

(10) Braking resistor unit

(7) DC reactor

(8) Noise filter

(9) Contactor

Peripheral Devices and Their ConnectionsPeripheral Devices and Their Connections

(11) Contactor for commercial power backup

(12) Zero phase reactor

(13) Thermal

relay

(14) Motor

15


29

No. Name Purpose and Selecting Points

1 Power transformer ・・・・Transformer capacity ＞＞＞＞ Inverter capacity ×××× 1.5

2 Circuit breaker・・・・Breaks accidental current (shortcircuit current). ・・・・Rated current ＞＞＞＞ inverter rated current ××××1.5 → Described in the inverter catalog.

3 Leakage breaker

・・・・Grounding protection・・・・High frequency leak current protection for electric shock accident & leakage current fire.

1. Use a breaker provided with countermeasures for high frequency leakage current. 2. Increase sensitivity current.3. Decrease inverter carrier frequency.

4 Contactor

・・・・Since the inverter has the contactor function, any contactor is not needed except for special cases.

・・・・When a braking resistor is used, insert a contactor to make thermal trip circuit.・・・・Perform RUN/STOP at the inverter side and set the contactor to “Always ON” to use.

57

AC reactorDC reactor

・・・・For high frequency current suppression and improvement of power factor・・・・Install a reactor to protect the inverter when the power supply capacity is large.

68

Noise filter orZero-phase reactor

・・・・Prevent radio noise generated by inverter section

910

Braking unitBraking resistor unit

・・・・Used when an electrical brake is needed (when the required braking torque exceeds 20%).

1112

Contactor for commercial power backup

・・・・Used for backup at inverter failure or when commercial power supply is used for normal operations.

13 Thermal relay・・・・Not needed when one motor is driven by one inverter. (Connected when more than two motors are used.)

How to Select Peripheral DevicesHow to Select Peripheral Devices


30

Inverter Functions and AdvantagesInverter Functions and Advantages

16


31

No. Advantage Technical Details Main Precautions

1

Can control speeds

of the specified

constant-speed

type motors.

Number of revolutions changes

when squirrel-cage-type motor

terminal voltage and frequency

are changed.

Since a standard motor has

temperature rise that becomes

greater at a low speed, torque must

be reduced according to frequency.

2

Soft start/stop enabled. Accel/decel time can be set freely

from a low speed.

(0.01 to 6000 seconds).

Set proper accel/decel time after

performing load operation.

3

Highly frequent

start/stop enabled.

Little motor heat generation since

smooth accel/decel is enabled with

little current.

Motor or inverter capacity frame

must be increased depending on the

accel/decel capacity. Check the

accel/decel time and load J.

4

FWD/REV run enabled without main

circuit contactor.

Because of phase rotation changes

by transistor, there are no moving

parts like conventional contactors

so that interlock operation can be

assured.

When applying the inverter to an

elevating unit, use a motor with a

brake to hold mechanically for

stand still.

Advantages of Inverter Applications (1)Advantages of Inverter Applications (1)

Cushion Startt

f

FWD Run

REVRun

Cushion Stop

Inverter

RUN CommandFWD Run

REVRun

t

f


32


5

Can apply an electrical brake. Since mechanical energy is converted into

electrical energy and absorbed in the

inverter at decel, the motor can auto-

matically provide braking force.

DC current is applied to the motor around

zero-speed so that it becomes dynamic

braking, to completely stop the motor.

Braking force is approx. 20% when

only the inverter is used.

Attaching a braking resistor

(optional) externally can increase

the braking force.

Pay attention to the capacity of the

resistor.

6

Can control speeds of the

motor under adverse

atmosphere.

Since the inverter drives squirrel-cage

motors, it can be used easily for

explosionproof, waterproof, outdoor or

special types of motors.

An explosionproof motor in

combination with an inverter is

subject to explosionproof

certification.

7

High-speed rotation enabled. Commercial power supply can provide up

to 3600 min-1 (2-pole at 60Hz) or 3000 min-

1 (2-pole, at 50Hz).

A general-purpose inverter can increase

frequency up to 400 Hz (12000 min-1) while

a high-frequency inverter can increase it

up to 3000 Hz (180000 min-1).

The speed of a general-purpose

motor cannot be increased by

simply increasing the frequency.

(It can be applied without being

changed if frequency is approx. 120

Hz.)

Mechanical strength and dynamic

balance must be examined. 60Hz 120Hz 400Hz

Electrical Braking


f

t

V

f

17


33


8

The speeds of more than one motor

can be controlled by one inverter.

The inverter is a power supply unit

to the motor, therefore, as many

motors as the capacity allows can

be connected.

These motors do not have to be the

same capacity.

The number of motor revolutions

differs depending on each motor

characteristics or load ratio even at

the same frequency.

(Among general-purpose motors,

speed deviation of 2 to 3% can be

considered.)

Synchronous motors have the same

number of revolutions.

9

Power supply capacity can be small

when the motor is started up.

Large current (5 or 6 times larger

than the motor rating) does not

flow as with a commercial power

supply start.

Current can be limited to at most

100 to 150% by low-frequency start.

Transformer capacity (kVA)

= 1.5 ×××× inverter output capacity

10Number of revolutions becomes

constant regardless of power supply

frequency.

Output freq. can be set regardless

of power supply freq. 50/60Hz.

Inverter


IM

IM

IM


34

Inverter Output Voltage

Inverter Output Current

Inverter Input Current

150%

150%100% Current

100% Current

100% Voltage (100% Speed)

t

Motor and Power Supply CurrentMotor and Power Supply Current

in Inverter Drivesin Inverter Drives

t

t0

18


35

Applied Load Concept of Energy-saving

Fans Pumps Blowers (Any Variable Torque Load)

Replace with a more efficient motor.

Reduce a redundancy of the facility for the actual loads.

Abate the head loss at valves or dampers.

(2)

(1)

(1)

Extruders Conveyors, etc. (Any Constant Torque Load)

Change to more efficient drives.

Replace the primary voltage control, secondary resistance

control, eddy-current coupling (VS motors) with a more efficient

control method(Frequency Control).

(3)

Cranes Elevators, etc.

Collect the regenerative energy at lowering by using the inverter

power supply regenerative function.

(4)

Rewinders Collect the regenerative energy of the rewinders.

Replace with a more efficient motor.

(4)

(2)

General Machines Reduce the starting energy.

(Use the inverter as a starter to stop the operations positively

whenever the load ratio is low.)

(5)a

Optimum EnergyOptimum Energy--saving Plan for Facilitysaving Plan for Facility


36

Chapter 7 Chapter 7

Harmonics, Noise & Surge VoltageHarmonics, Noise & Surge Voltage

19


37

Noise Harmonics

Frequency Band High frequency

(10 kHz or more) 40th to 50th harmonics (up to several kHz)

Main Source Inverter section Converter section

Transmission Path ・・・・Electric wire (conduction)

・・・・Space (radiation)

・・・・Induction (electrostatic,

electromagnetic

Electric wire

Influence Distance, wiring distance Line impedance

Generating Amount ・・・・Voltage variation ratio

・・・・Switching frequency

Current capacity

Failure ・・・・Sensor malfunction

・・・・Radio noise

・・・・Overheat of capacitor for P.F improvement

・・・・Overheat of generator

Corrective Actions ・・・・Change the wiring route.

・・・・Install a noise filter.

・・・・Install INV. in a screened

box

・・・・Install a reactor.

・・・・12-phase rectification

・・・・Sinusoidal wave power regeneration

converter 主な

主な主な主な

Difference between Harmonics and NoiseDifference between Harmonics and Noise


38

Co

mm

erc

ial

Po

wer

+

Sm

oo

thin

g

Cap

acit

or

Converter Section

Motor

Bridge Rectifier

ＭＭＭＭ

Harmonics Current Generated by Rectifier Circuit

Noise Generated by High-speed Switching

Harmonics and Noise SourcesHarmonics and Noise Sources

Inverter Section

20


39

Without Filter →

(a) Test Circuit

[Inverter Output] [Motor Input]

(b) Result of Waveform Observation

(5µs/div, 250/div)

Expanded Diagram

With Filter →

Inverter Output Motor Input

IM

Surge Voltage Suppression by FilterSurge Voltage Suppression by Filter

Filter

Expanded Diagram

PWM Inverter


40

The solution to 400V class inverter drive problems

1. Low surge voltageSuppresses motor surge voltage, eliminating theneed for the motor surge voltage protection.

2. Low electrical noise (Radiated, Conductive)

3. Low acoustic noise

4. Electrolytic corrosion of motor bearings due to shaft voltage

Features of 3Features of 3--level control level control

21


41

(b) Example of Shaft Voltage Measurement (between Shafts) (c) Shaft Voltage Waveform

(Hz)

Commercial Power Supply Drives

Actual Measurement of Shaft VoltageActual Measurement of Shaft Voltage

Commercial Power

Drives

(Direct-coupling Side)(Opposite to Direct-

coupling Side)

Sh

aft

Vo

lta

ge

(mV

)

Inverter

Inverter Drives

V: Measuring DeviceR: Non-inductive Resistor (1kΩ)

(Stator)

(Rotor)

(a) Example of Shaft Voltage Measuring Circuit

Inverter: PWMMotor: 3.7 kW, 200 V, 4 polesV/f characteristics: Constant torque


No. U030701-Page 42

Improving output voltage

Reducing

component losses

Speed

sensor

Drive section

AC power supply

Processing

section

New Inverter Technology

⑤⑤⑤⑤ New power conversion method

How to improve inverter efficiency

①①①① Reducing loss

②②②② Improving PWM control

③③③③ Improving inverter output voltage waveform

④④④④ Improving the drive’s input power factor

Improving input power

factor

Improving PWM control

New power conversion

method

The diagram below illustrates five steps that can be taken to improve motor control and inverter drive

performance: ①①①① Reducing the loss generated in the inverter unit; ②②②② and ③③③③ concern circuitry and the

control method used for high-efficiency performance; ④④④④ covers improvements to drive’s power supply side;

⑤⑤⑤⑤ involves a new approach to power conversion.

Motor

22


No. U030701-Page 43

8.6%

60.8%

5.3%

0.2%

0.8%

1.0%8.1%

15.3%

Rectifier diode IGBTs Smoothing capacitors ＭＣMain circuit fuse

Discharge resistance

Control power supply

Others

Reducing Inverter Component Loss

12.4%

43.6%7.6%

0.2%

1.1%

1.5%

11.6%

22.0%

BEFORE NOW

Improving the switching characteristics of the IGBT device has reduced the power loss to the

half of what it was 10 years ago. In addition to reducing power consumption for the control

power supply and control circuit, inverter efficiency is 9o% better than in the past.

One way to improve inverter efficiency is to reduce loss from various components. The circle graphs

below show the amount of loss generated from each component in the drive. About 10 years ago, the

loss generated from IGBT (Insulated Gate Bipolar Transistor) switching in the main circuit exceeded

60% of all loss. Recent improvements in switching technology have now minimized loss from IGBTs

down to 40%.

Rectifier diode IGBTs Smoothing capacitor ＭＣMain circuit fuse

Discharge resistance

Control power supply

Others


No. U030701-Page 44

Improvements with PWM Control

High-efficiency PWM control: 2-phase modulation

(b) 3-phase modulation

Output voltage Output current

(a) 2-phase modulation

Output voltageOutput current

Switching loss is not generated in the 2-phase

modulation method since IGBT switching does not

occur in this area.

Employing 2-phase modulation can reduce

IBGT switching loss by approximately 30%.

The high carrier frequency used in PWM (pulse width modulation) increases the amount of IGBT

switching loss. Yaskawa has created a 2-phase modulation method to minimize this switching loss.

As shown below, the 2-phase modulation method stops switching when current is large. This way, one

of the 3 phases is always in the stopped status. Using this 2-phase PWM control method can reduce

the switching loss by approx. 30%.

23


No. U030701-Page 45

Improving the Output Voltage Waveform

Common Problems

① Motor insulation damaged by surge voltage

② Peripheral devices malfunctioning due to noise

generated by the inverter

③ Earth leakage breaker malfunctioning due to leakage

current

④ Motor bearings corroded by shaft current

Solved with Solved with

33--level control! level control!

Although high carrier PWM control makes the output current waveform very close to sinusoidal, the

actual voltage waveform created is still a group of square waves. The surge voltage generated at rising

and falling edges of this square waves causes trouble. A surge suppression filter is normally attached

between the inverter and the motor in order to prevent the motor insulation from being damaged by

surge voltage. This filter is called RLC filter, and is is composed of a resistor, reactor, and a capacitor.

A large filter is not needed if the inverter and motor are close together. If they are far apart, however, a

large capacity filter is needed. For example, with the motor capacity of 75 kW, the filter consumed

power is 0.3 kW, 1.4 kW and 12.6 kW when the wiring length is 30 m, 100 m and 300 m, respectively.

As the distance gets longer, the required capacity is sharply increased. Additionally, the size of the

filter also becomes larger, it will be necessary to examine where to install. To omit this filter, 3-level

control inverters have been devised. Using these inverters can solve the problem of ①①①①. Furthermore,

this control method can reduce the remaining 3 failures (②②②②, ③③③③ and ④④④④) at the same time.


No. U030701-Page 46

What Is 3-Level Control?

Varispeed G7: 3-level controlConventional Drives: 2-level control

VPN /2

＋＋＋＋

００００

－－－－

VPN /2

VPN

＋＋＋＋

－－－－

VPN : DC bus bar voltage = AC input voltage ×××× √２２２２

VPN

U V W

ＰＰＰＰ

ＮＮＮＮ

VPN

U V W

ＰＰＰＰ

ＮＮＮＮ

００００

Volt

ag

econ

trol

by

12

tran

sist

ors

Volt

ag

e co

ntr

ol

by 6

tra

nsi

stors

Circuit

configu-

ration

Phase

voltage

Line

voltage Volt

ag

e fl

uct

uati

on

re

du

ced

to h

alf

of

con

ven

tion

al

mod

el

A

B

C

D

E

F

VPN

24


No. U030701-Page 47

(a) Circuit configuration during for one phase (b) Switching patterns

A B C D Potential

ＯＮＯＮＯＦＦＯＦＦ Level P

ＯＦＦＯＦＦＯＮＯＮ Level N

ＯＦＦＯＮＯＮＯＦＦ Level O

Principle of 3-Level Control MethodIn conventional 2-level control, 2 transistors are used for each phase, making a total of 6 transistors for 3

phases to switch DC bus bar voltage VPN. Phase voltage turns ON and OFF depending on the size of VPN,

and changes according to it. In the 3-level control, 4 transistors are used per phase, for a total of 12

transistors for 3 phases. The illustrations below shows how transistors switching works during one phase.

In this figure, voltage P appears in phase U when transistors A and B turn ON. Then O appears in phase U

through diodes E and F when transistors B and C turn ON. N appears when transistors C and D turn ON.

It means that phase U can take three states: P, N, and O. This is how 3-level control was named. While

voltage fluctuates between P and N in 2-level control, it fluctuates between P & O, and between O & N in 3-

level control. Therefore, phase voltage turns ON and OFF depending on the size of VPN/2, which is half of

VPN during 2-level control. This creates an output waveform very close to a perfect sine wave. Surge voltage

is cut in half when voltage fluctuation becomes half, which means that noise and leakage current is also cut

in half, resulting in reduction of shaft current.

A

B

C

D

VP N

MotorVP N

２

VPN

２

VPN : DC bus bar voltage

P

N

O

PVPN

2O

N

E

F

(phase U appears below)

Phase U


No. U030701-Page 48

Comparison of Surge Voltage Waveform in 3-level Control Method

Suppression effect

VPN

770 V peak

0

VPN

1200 V peak

0

(a) 2-level control surge voltage waveform (b) 3-level control surge voltage waveform

The following figures show the output voltage waveforms of 400 V class inverter 2-level control and

3-level control, respectively. In the 2-level control method, the peak value of the waveform is almost

1200 V, while it is limited to 770 V in the 3-level control method. Since this value is lower than the

insulation voltage of the 400 V class motor, the existing motors can be driven by an inverter without

using surge suppression filters.

25


No. U030701-Page 49

Comparison of Radiation Noise in 3-level Control Method

20

030

40

60

80

100

Lev

el

dBµ

V/m

50 70 100 200 300

Frequency (MHz)

Max. 20 dB down20

0

40

60

80

100

Lev

el

dBµ

V/m

30 50 70 100 200 300

Frequency (MHz)

These graphs show noise levels. In the frequency bandwidth between 30 MHz and 300 MHz, the

noise level is limited to 20 dB at the maximum. This reduces the effects on surrounding peripheral

devices caused by noise.


No. U030701-Page 50

Comparison of Leakage Current in 3-level Control Method

11111111AAAA

5555AAAA

(a) Leakage current in 2-level control method (b) Leakage current in 3-level control method

The graphs below compare leakage current in 2-level and 3-level control. Leakage current in the 3-level control method is almost the half of that in the 2-level control method. Less leakage current means fewer faults with the leakage breaker.

26


No. U030701-Page 51

No Surge Suppression Filter Needed Because of Surge Reduction

Configuration of surge suppression filter

Reactor

AC

pow

er

sup

ply

Surge suppression filter

Wiring distance

Heat energyHeat energy

Not needed!

Motor

InverterVarispeed G7

Capacitors

Resistors

Cf: Capacitor size is determined by cable type or wiring length

E: DC bus bar voltage (600 V at 440 Vac input)

fi: Inverter carrier frequency

××××2: Multiplied by 2 for charging and discharging of capacitor

Consumed power WR of the resistor is

calculated as follows:

WR = Cf････E2････fi××××2

3-level control contributes to energy saving because there is no need for a surge

suppression filter that would otherwise consume power.


No. U030701-Page 52

0

10

20

30

40

50

60

70

80

90

Operating conditions: Motor specifications: 440 V, 75 kW

When 100sq polyethylene sheath cable is used

Consumed power WR of

resistor for wiring distance

0 200 400 600 800 1000

Wiring length (m)

Consu

med

pow

er o

f re

sist

or

WR

(kW

)

15

Long distance drastically Long distance drastically

increases power consumptionincreases power consumption

Long distance drastically Long distance drastically

increases power consumptionincreases power consumption

How wiring length affects power consumption of a surge suppression filter resistor

Energy saved because no filter is used

Power Consumption of Surge

Suppression Filter

27


Maintenance and Inspection Maintenance and Inspection


Failure PatternsFailure Patterns

Initial Failure Period

Accidental Failure Period Wear-out Failure Period

t

Specified Failure Ratio

Service Lifetime

Failu

re

Ratio

λ (

t)

0ta tb

28


55

Place Item Checking ItemSchedule

Daily Periodical1-yr 2-yr

WholePeripheral environment Ambient temperature, humidity, dust, hazardous gases, oil mist, etc.

Whole unit No excessive vibration or noise. Power supply voltage Check that main circuit voltage or control voltage is normal.

Main Circuit

Whole① Megger check between main circuit terminal and ground terminal② No loose connections③ No traces of overheating in components④ Clean.

Connected conductor, Power supply

① No distortion in conductor② No breakage or deterioration (cracks, discoloration, etc.) in cables

Transformer, Reactor No odor, excessive beats or noise Terminal stand No damages

Smoothing capacitor① No liquid leakage② No projection (safety valve) or bulge③ Measure electrostatic capacity and insulation resistance.

Relay, Contactor① No chattering at operations② Timer operation time③ No roughness on contacts

Resistor ① No crack in resistor insulating material② No disconnection

Control Circuit, Protective

Circuit

Operation check① Balance of output voltage between each phase by inverter single-unit operation② No failure in protective or display circuit by sequence protection test

Component check

Whole ① No odor or discoloration② No excessive corrosion

Capacitor No traces of liquid leakage or deformation

Cooling System Cooling fan

① No excessive vibration or noise② No loose connections③ Clean the air filter.

Display Display ① All lamps lights correctly.② Clean.

Meter Indicated values are correct.

(From JEMA Information)Daily Inspection and Periodical InspectionDaily Inspection and Periodical Inspection


56

NameNameNameNameStandard Standard Standard Standard

Replacement Replacement Replacement Replacement PeriodPeriodPeriodPeriod

MethodMethodMethodMethod

Cooling fanCooling fanCooling fanCooling fan 2 to 3 years2 to 3 years2 to 3 years2 to 3 years Replace.Replace.Replace.Replace.

Smoothing capacitorSmoothing capacitorSmoothing capacitorSmoothing capacitor 5 years5 years5 years5 years Replace on investigation.Replace on investigation.Replace on investigation.Replace on investigation.

Breaker, relayBreaker, relayBreaker, relayBreaker, relay －－－－ Determine what to do on Determine what to do on Determine what to do on Determine what to do on investigation.investigation.investigation.investigation.

TimerTimerTimerTimer －－－－ Determine after checking the Determine after checking the Determine after checking the Determine after checking the operation times.operation times.operation times.operation times.

FuseFuseFuseFuse 10 years10 years10 years10 years Replace.Replace.Replace.Replace.

Aluminum capacitor Aluminum capacitor Aluminum capacitor Aluminum capacitor on PC boardon PC boardon PC boardon PC board 5 years5 years5 years5 years Replace on investigation.Replace on investigation.Replace on investigation.Replace on investigation.

Note : Operational Conditions

・・・・ Ambient temperature : Annually 30 in average

・・・・ Load ratio : 80% or less

・・・・ Operation ratio : 12 hours or less per day

Component Replacement Guidelines Component Replacement Guidelines

29


57

* Clamp meters available on markets have differences in characteristics between manufacturers.

Especially, measured values tend to be extremely small at low frequency.

Precautions on MeasurementPrecautions on Measurement

Inverter Approximate Waveform Element Meter

Input Voltage All effective

values

Moving iron type

voltmeter

Current All effective

values

Moving iron type

ammeter

Output Voltage Fundamental

wave effective

value

Rectifier type

voltmeter (Model

YEW2017, etc.)

Current All effective

values

Moving iron type

ammeter *


58

Purpose and Types of Protective FunctionsPurpose and Types of Protective Functions

Inverter Protection

Pro

tecti

on

Warn

ing

Motor Overheat Protection

Others

Operation status is not proper.

Prediction of protective

function operation

Overcurrent OC

Overvoltage OV

Grounding GF

Main circuit undervoltage UV1

Cooling fin overheat OH

Braking transistor error rr

Inverter overload OL2

Motor overload OL1

Overtorque detection OL3/OL4 lit

CPU error CPF

Overtorque detection OL3/OL4 (blinking)

Undertorque detection UL3/UL4 (blinking)

Inverter overheat prediction OH2

Radiation fin overheat prediction OH

30


59

Main circuit overvoltage : OVApprox. 410 V(Approx. 820 V)

Approx. 380 V(Approx. 760 V)

Voltage at stall prevention during deceleration


Voltage at braking


Main circuit

undervoltage : UV1 ※※※※

DC Voltage

Voltage in the parentheses shows 400-V series.

Inverter output overcurrent : OC

Overload anti-time-interval characteristics

Stall prevention level during running ※※※※

Inverter rated output current

Current

200%

160%

100%

Stall prevention level during acceleration ※※※※

150%

Level at Which Protective Function OperatesLevel at Which Protective Function Operates

※※※※ Can be changed.


NOTE :

yaskawa ac drive gt 1

Documents

commercial

power supply

power supply

pulse width

power supply

dotted line

level control

surge suppression