atv71_m10_network braking unit v5 en_.ppt

8/10/2019 ATV71_M10_Network Braking Unit V5 EN_.ppt

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Altivar 71 Training

ATV71_regen-harmonic modules V3 EN 126/10/20148 Sept 2004 STIE \ Bertrand Guarinos

Network B raking Uni ts


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Summary

ATV71

26/10/2014 STIE Bertrand Guarinos ATV71_regen-harmonic modules V3 EN

I The Offer

II How it works ?

III Sizing principal

IV Sizing example

V Appendix

Summary


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Summary

ATV71


I The Offer

II How it works ?


IV Sizing example

V Appendix

Network Braking Units


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Summary

ATV71


Introduction

With ATV71 came a new range of option: theNetwork Braking Unit

This device allows toregenerate power onto the network when the drive system isworking as a generator.

ATV71 offer is well optimised for duty cycle up to 50% with 5mn braking time

It may replace braking resistors in system witch have quite long generating cycle or

high braking power needs like : hoisting, high inertia machines ..

For such applications, it's agood compromise volume/efficiency/cost.

And the energy saving allows a quick paying off.


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ATV71


Offer

Customer benefits

Small compact housing

User friendly first start up, no programming or adjustment necessary

Limitation of the harmoniccurrent regen on the main (line chokes)

DC-bus coupling of several controllersis possible

Up to 4 units can be paralleled(no derating)

DC bus short circuit protection(fuses)

Overload protectionduring back feed operation

97% efficiency

Overvoltage, rotating field sequence and temperature detection

IGBT technology

Self synchronizing


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ATV71


When do I need a Network Braking Unit ?

Advantages of the NBU compare to braking resistors

Energy saving

Volume saving

Efficiency

Quick response

Smooth DC bus voltage regulation

Disadvantages

The cost

Can't regen in case of network cut (no ride through operation)

Can increase a little the network voltage (supply impedance must be


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Summary

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Offer

Main specifications

2 power ranges

380V- 415V 7kW to 200kW

440V-480V 18kW to 180kW

Frenquency :40 - 60Hz +/-10%

Effiencency : 97%

Cos = 1

Line inductance(4% to 6% => THDI


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Summary

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Offer

7,6

13.8

22

33

45

70

90

135

160

200

250

345

Ppeak

400V380V-415V offer

from 7 to 200kW

continuous braking

power

3..minaclinepeak

IrmsUP


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Summary

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Ex of NBU paying off calculation

Ex for a hoist application

Braking power Pb = 100kW

Braking time per cycle tb = 10s

Number of cycles per hour n = 30/ h

Operation hours per day h = 18h / d

Working days d = 350d / y

Energy-costs K = 0,1 EUR / kWh

Costs of the power feedback unit RK = 6600 eur

Costs of equivalent braking resistor CK = 2800 eur

Energy saving per year

Energy-costs saving per year:

Paying off in days:

The network feedback unit is paid off within 9 months.

3600

350183010100 yddhhskWW

///

yearkWhW /52500

KWE

kWheakWhE /ur,/ 1052500 yeareE /ur5250

FKBntP

CRA

TBB

KK

)(

eu rdhhskW

seu reu rA

10183010100

360028006600

,//

)(

days254A


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Summary

ATV71


I The Offer

II How it works ?


IV Sizing example

V Appendix



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Summary

ATV71


Network Braking Units internal structure

Internal diagram VW3A7211 (135kW)

N t k B ki U it ki


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Summary

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Network Braking Units working

DC bus management

II The DC-bus voltage increases, when the motor is in regenerative mode. The feedback current increases

straight proportionally with the DC-bus voltage.

IV The difference between the generated and inverted voltage and the mains voltage is the necessary

voltage which drives the current back to the mains. Therefore the mains network operates as energy drain,

where a minimal voltage increase can be seen (depending on the network impedance at this point).

V Between 620 and 630V DC the IGBTs trip due to an overcurrent -> the NBU is locked till reset operation.

The time delay for overcurrent tripping is 10s.

460Vac

444Vac

400Vac

II

I

III

IV

V

620-630Vdc Ir = 120% Imax

NBU tripping Threshold

600Vdc Ir = 100% Imax

max peak power

540Vdc Ir = 0% Imax

750-850Vdc

Drive tripping Threshold

Example for a 400V NBU :

M i f t


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Summary

ATV71


Main features

Set up

No settings, in factory configuration the NBU is ready to work

However :

Check the supply voltage is corresponding to the NBU name plate

Check the network connection L1,L2,L3 (the phase rotation must be respected)

Check the DC bus connection from the drive (+/-)

Check the fan supply connection (>45kW)

Check the fault relay is connected to external fault input of the drive

At voltage turn on the green led is lighten the NBUis ready to work

In case of fault there are other leds for trouble shooting

1. red: phase failure

2. red: overcurrent

orange: overtemperature

The reset button allows acquit the fault

Internal jumpers allow to set different ways of tripping and autostart in case of fault

N t k B ki U it


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Summary

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I The Offer

II How it works ?


IV Sizing example

V Appendix


Si ing of the Net ork Braking Units


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Summary

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Sizing of the Network Braking Units

The basics

Sizingthe Network Braking Units for the technical and economic optimum requires toknow several characteristics of the application.

Without this knowledge you choose the NBUin accordance with the continuous and

maximum power rating of the drive.

Naturally this will not lead to the best economic solutionas most often the NBUwill be

oversized.

The sizing can be done in 3 steps :

- 1. Calculate the electrical braking power to feedback

- 2. Calculate the NBU peak power(function of the minimum network voltage)

- 3. Choose the corresponding NBU power rating



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Summary

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Electrical braking power calculation

To size the Network Braking Units you must know :

thepeak braking power Pb to feedback

the mean braking powerPb to feedback

Ex of a braking power cycle :

The power is depending on the cycle, the inertia, the load and the efficiency of the system.

Braking power

Pb2Pb1

T

t0 t1 t2

Pb

Pb T

tPtPtPP bbb

b

221100...



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Summary

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Real regenerating power

The braking power calculated results of the energy that is fed back from the mechanical

system.

Not the whole energy comes back to the Network Braking Units unit.

Themechanical friction, inverter losses help for braking.

Theselossesare generally represented by theefficiency () of the system.

In an other hand some loads can increase the braking power, as for example the wind

on a crane jib arm.

Anyway, it's good to take a safety margin.

For example, to simplify the calculation, efficiency (if not supposed very bad) can be

considered = 1.

drive m o tm ect ..

tm ecbrealb PP



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Summary

ATV71



Power flow during regenerating phase

L1L2L3

UV

W

M

3 ~

Drive

Network Braking Unit

NetworkM, w

J

L1L2L3

Input-rectifier DC-bus-

capacitor

Inverter Motor

Load

Power

regenerated

onto the network

Motor

losses

Mechanical

losses

System

mechanical

Power

Motor elec.

power

Motor mec

power

Inverter

losses

Network

Braking

Units

losses

Braking

power

cos... 3mmem

IUP .TPmm

mecm o tdm ecb PP ... dtd

JPmec

2

.

dcdcdr IUP .

3..minmax nr

IUP



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Summary

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Some efficiency datas*

Drive efficiency

0.37- 1.5kW 0,9-0,94 2.2kW-500kW 0,95-0,97

AC Motor efficiency (standard)

0.37-3kW = 0,75-0.82

4-7.5kW = 0,85

11-55kW =0.9-0.93

75-500kW =0,95

Transmission part efficiency

Gear box = 0.8-0.95

Pignon-Rack = 0.7-0.8

Belt or Chain = 0.95

Endless screw = 0.6-0.8

*Can be used for a first approach calculation



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Summary

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Effective regenerating power

With a Network Braking Units the power regenerated is depending on the network

voltage.

Thus the minimum network voltage must be consideredin order to size the unit.

Ex :

for an application32kW barking peak poweris calculated

33kW 400V unit VW3A7204 is chosen

but the network voltage can decrease to Umin = 340V

max ac currentfor VW3A7204 => In= 48A

If we take into account the min voltage, the peak regenerating power availableis only :

It would be better in this case to choose a range above VW3A7205 (45kW 400V)

kWPIUPrnr 283340483 ....

maxminmax



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Summary

ATV71


I The Offer

II How it works ?


IV Sizing example

V Appendix


ATV71

Sizing of the Network Braking Units ex.1


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Summary

ATV71



Simplified example for a hoist application

Motor torque

t

Speed

Network = 400V +/-5%

Braking power reflected on the

motor shaft160kW

Motor efficiency=0.9

Drive efficiency=0.98

Braking

Power

3s 3s 3s30s 40s

T1=40s T2=3sT0 = 79s

1.8 Tn

0.8 Tn

0.8 Tn

1.8 Tn

up

down

kWPb 54588034079

316081504016080..

)..().(

88098090 ... t

tnb PP 81.

t

bbb

bT

tPtPtPP .

...221100

kWPb

25388016081 ..

Peak regenerative power :

Mean regenerative power :

Efficiency :

ATV71



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Summary

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Choice of the braking unit

1- Choose a module witch maximumpeak power

is equal or higher the peak braking power

calculated (230kW).

Ppeak power of the module VW3A7212:

Ppeak = Irms*Umain*SQR3 Ppeak

=500*380*SQR3 = 329kW > 253kW

2- Check that the continuous poweris

equal or higher than the mean braking

power calculated (45.5kW).

P mean = 200kW >45.5kW

Or check with the duty cycle

ATV71



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Summary

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Exemple of using the catalogue diagram for a cycle

Example 1:

necessary braking power : 33 kW

braking duration : 2 min.

time between two brakes : 5 min.

Evaluation: In this case the point of

intersection of braking time and

intermission time is below

the thermal limited power graph in the

allowed area this operation cycle is

allowed.

Example 2 :

necessary braking power : 45 kW

braking duration : 3 min.

time between two brakes : 3 min.

Evaluation: In this case the point of

intersection of braking time and

intermission time is above

the thermal limited power graph.That means this operation cycle is not

allowed.

Remark: In case of an intermission time

of e.g. 3,5 min. this operation cycle

would be allowed again

ATV71



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Summary

ATV71


I The Offer

II How it works ?


IV Sizing example

V Appendix

g

ATV71

Example of association of several modules


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Summary

ATV71


p

2x Regen

modules

110kW

VW3A7210

ATV71

90kW

ATV71

90kW

ATV71

110kW

ATV71

45kW

Regen

module

26kW

VW3A7205

Up to 4 modules // possible, the

range can be different.

ATV71

Calculation of mechanical braking power


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Summary

ATV71


g p

Braking power for an horizontal movement (ex trolley)

constant deceleration (n->0) and negligible inertia and friction

Braking power

Pb

tb

Pb

Speed

Torque

bb PP . 2

b

ki n

b

t

EP 2

2

1vmE

kin..

inrv ...

Ekin (j)= kinetic energy

m (kg) = mass of the mobile

v (m/s)= linear speed

r (m)= radius of the wheel

n (t/s)= motor speed

i = gearbox ratio

tb

(s) = time to stop

Pb(W)= mean braking power during stopping

Pb(W)= peak braking power during stopping

n


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ATV71



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Summary 326/10/2014 STIE Bertrand Guarinos ATV71_regen-harmonic modules V3 EN

Braking power for constant speed (ex motor test bench)

negligible acc/dec power, inertia and friction

Braking power

Pb

tb

Speed

nTPP bbb ...

2

Tb (N.m)= braking torque

n (t/s)= motor speed


g (m/s2)= gravity acceleration

m (kg) = mass of the mobile

Pb(W)= mean braking power during stopping

Pb(W)= peak braking power during stopping

M

n

G

Torque

Tb

vgmPPbb

..

ATV71



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Summary 326/10/2014 STIE Bertrand Guarinos ATV71_regen-harmonic modules V3 EN

Calculation formulas of the braking power for a vertical movement

T (s)= total cycle time

t0(s) = stop time + ascent time t1

(s)= descent time t2

(s) = stop time in descent

Pb1(W)= mean braking power during descent

Pb2(W)= mean braking power to stop in descent

Pb2(W)= peak braking power to stop in descent

m(rd/s)

=max angular speed

Jtm(kg.m2)= total inertia reflected to the motor

g (m/s2)= gravity acceleration (9,81)

a (m/s)= load deceleration


T

tPtPP bb

b

2211..

Braking power

Pb2Pb1

Pb

T

t0 t1 t2

Pb2

Braking Torque

Speed

vgmPPbb

.. 11

Up

down

1

2

2t

JvagmPb .)..(

2

2

2

b

b

PP

atv71_m10_network braking unit v5 en_.ppt

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