Speed Variable Pump Drives Technology

9/6/2012 | DCUS/SET1 | © Bosch Rexroth AG 2012. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in

the event of applications for industrial property rights.

Speed Variable Pump Drives Technology

Jan Komsta

Bosch Rexroth

September 2012

1



Saving energy and increasing productivity

Variable-speed pump

drives offer:

Reduced energy consumption

Reduced average noise

Compact drive size

Reduced cooling requirements for

oil

High robustness

Intelligent hydraulic drive

2



Motivation, market drivers: Energy costs

5

6

7

8

9

10

11

12

1995 1998 2001 2004 2007 2010

Average price electrical energy

European Union (EU 15) Source: Eurostat

EURO CENT

3

Average price electrical energy

USA

Source: www.eia.gov/electricity/data/state

US CENT



Total Cost of Ownership (TCO)

Motivation, market drivers: Energy costs

Machine

&

Equipment

Investment

costs

Operating

costs

Commissioning

Training

Spare parts

Maintenance

Staff costs

Taxes

Insurances

Energy Retrofit

Disposal

...

80 ... 95 %

5 ... 20 %

AC motor 1 kW

5 year operation

Acquisition costs

approx. 250 $ (4%)

Energy costs approx. 5,950 $ (96%)

4



Drive Technology Choices

drive power transmission Properties

Constant speed

electric motor classic hydraulics

Hydraulic pump control motor /

cylinder Power density, robustness

Controllability

Multiple consumers possible

Noise

Energy efficiency

Force transmission Spindle drive

Electro-mechanic Variable speed

motor drive

Controllability

Noise

Energy efficiency

Multiple consumers not

possible (or very difficult)

Power density

Hydraulic pump motor /

cylinder Power density, robustness

Controllability

Multiple consumers possible

Energy efficiency

Noise

variable speed pumps

w/o valves

Variable speed

motor drive

5



System Solutions

(for large drives)

Servo Motor + Drive

+ variable pump

Motor + VFD

+ variable pump

Fixed speed motor

+ fixed pump

Motor + VFD

+ fixed pump

Fixed speed motor

+ variable pump

Efficiency

(for large drives)

Servo Motor + Drive

+ fixed pump

Costs Dynamics

M 3 ~

M 3 ~

M 3 ~

M 3 ~

M 3 ~

M 3 ~

6

7 9/6/2012 | DCUS/SET1 | © Bosch Rexroth AG 2012. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in


Energy saving… but how?

Conventional systems

Constant speed AC motor with variable

displacement pump (i.e. pressure

compensated)

Flow rate is a function of swivel angle α:

Motor torque is a function of swivel angle,

α, and pump pressure, p:

n=constant

α 0% :

Vp(α) = 0

α 100 %:

Vp(α) = max

α

1000

)( volP nVQ

.20

)(

mech

PVpM

Vp(α) n= constant

Axialkolben-Pumpe.swf




Conventional systems: overall efficiency

Swivel Angle [%] Load of Motor M/M_nominal [%]

Overall pump efficiency

for n= constant

Pu

mp

Eff

icie

ncy

[%

]

Mo

tor

Eff

icie

ncy [

%]

.20

)(

mech

VpM

Low pressure

High Pressure

Swept volume Swivel angle

V ~ α




Conventional systems:

overall efficiency

Efficiency of conventional system

is low during partial load

operation:

Pressure Holding

Idling

For α <40-50%

High saving potential!

Q, p

n= const. Vp(α)

Pressure holding

Qsys/min




10

1. Fixed displacement

pump

Constant speed

2. Variable disp. pump

Constant speed

3. Fixed/ var. disp. pump

Variable speed

M 60 Hz

M 60 Hz

M

Useful energy

Losses Total energy

Useful energy

Losses Total energy

Throttling losses

eliminated

Less power

consumption during

partial load operation

Useful energy

Losses Total energy

Minimized / no power

consumption during

partial load operation

Motor heating

Pump losses

Throttling losses (valve)

Lowest efficiency

during partial load

operation

Energy saving




SvP 7000

Basic performance High performance Advanced performance

FcP 5000 DFEn 5000

Sytronix

Sytronix – Bosch Rexroth Variable-Speed Pump




12

Sytronix – FcP 5000

Constant pressure system

basic performance required

pressure control

pressure control

Flow control

force control

speed control

position control

Control functions

Performance

Quadrants

1 flow

pressure

Machine tool

FcP 5000

System

Sample application

energy

efficient

M 3~

3~

P U

basic dynamics

basic accuracy

http://www.google.de/imgres?imgurl=http://ellagsaeure.vitamin-power.eu/assets/images/Gruener-Haken.jpg&imgrefurl=http://ellagsaeure.vitamin-power.eu/html/firmengrundsatz.html&usg=__txR33NN_VdB0tr3foXMQLZ4NR8Y=&h=346&w=346&sz=22&hl=de&start=1&zoom=1&tbnid=e0yDGVPJk7c5KM:&tbnh=120&tbnw=120&ei=TulPTZPGF4bwsgaQv9ybDw&prev=/images?q=gr%C3%BCner+haken&um=1&hl=de&sa=N&tbs=isch:1&um=1&itbs=1





13

Sytronix – DFEn 5000

Constant pressure system

advanced performance required

pressure control

pressure control

Flow control

force control

speed control

position control

Control functions

Performance

Quadrants

1 flow

pressure

Wood working machine

DFEn 5000

System

Sample application

2

energy

efficient

M 3~

3~

P U

n_CMD

advanced dynamics

advanced accuracy





Sytronix – DFEn 5000

Based on variable displacement pump A10VSO, pressure + stroke

control

Frequency converter (HCS03)

Standard motor (inverter duty)

Advanced dynamics

p/Q-control


speed

flow

swivel angle

Maintain high pump

and motor efficiency,

swivel angle α>80%




15

Sytronix – SvP 7000

Axis control

high performance required

force control

speed control

position control

Press brake

SvP 7000

pressure control

Flow control

force control

speed control

position control

control functions

Performance

Quadrants

1 2

4 3

flow

pressure

System

Sample application

energy

efficient

M 3~

3~ SG

n

s

P U

high dynamics

high accuracy






http://www.boschrexroth.com/industrial-hydraulics-catalog/Vornavigation/Vornavi.cfm?Language=DE&VHist=g54590&PageID=p77961



Sytronix – SvP 7000


Internal Gear Pump PGH (Fixed Displacement Pump)

• Very high efficiency

• High drive speed

• Low pressure ripple

• Low noise

• Low mechanical inertia

Synchronous servo motor

• High dynamics

• Low mechanical inertia

• High power density

Servo frequency converter HCS03

• Dedicated flow and pressure controller (p/Q)

• Leakage detection/ compensation

• Safety functions; i.e. torque limitations, anti-cavitation

protection…



SvP 7000 Pressure Control


High accuracy pressure control

Pressure rise and fall times equal

(T95% < 150ms at oil volume < 5 l)

No overshoot or undershoot

pressure

10 bar

150bar

speed

3000 rpm

-3000 rpm

T95%= 150ms

0 s 1.5 s

low RPM during pressure hold



SvP 7000 Flow Control


High Dynamics improve cycle time

Flow control response twice as fast

as conventional hydraulic pumps

Can save approximately 400ms per

cycle (i. e. 5% improvement in an 8s

cycle)

High repeatability due to high

accuracy speed control

High accuracy at very low flows

Leakage detection and compensation

Flow Up Down

T25% 15 ms 10 ms

T50% 26 ms 18 ms

T75% 36 ms 24 ms

T100% 57 ms 35 ms

time T25%

System example SVP-SF-1X/075-S2

T50% T75% T100% T25% T50% T75% T100%

Up Down



Functionality and Requirements

19

Constant

pressure

system

Dynamics

300ms

p/Q, Pos

Marine &

Offshore

Metallurgy Bulk material

Handling Wood, paper

1

2

Axis-

control,

p/Q, Pos

p/Q

control

Dynamics

50ms

Dynamics

150ms

Dynamics

300ms

< 7,5 kW >7,5 to 37 kW >60 kW >37 to 60 kW

Machine

tools

Presses

Presses

Die casting Injection molding

machine



Functionality and Requirements

20

Constant

pressure

system

Dynamics

300ms

p/Q, Pos

1

2

Axis-

control,

p/Q, Pos

p/Q

control

Dynamics

50ms

Dynamics

150ms

Dynamics

300ms

< 7,5 kW >7,5 to 37 kW >60 kW >37 to 60 kW

DFEn 5000

SVP 7000

FcP 5000



Noise Reduction with Speed Variable Pump

21

RPM

Variable pump

Axial piston pump A10

71cc

50 bar

1750 RPM

Sytronix constant pump

Internal gear pump PGH

40 cc

50 bar

75 - 3000 RPM

Part load

-20dB(A)

Full load

-5dB(A)

No

ise

[d

B(A

)]

1

2 1

2

1

2

Partial load (pressure holding)

Full load (max flow rate)



Application Example: FcP 5000 for Machining Center

22

* Energy mix, Germany according to GEMIS version 4.2 in year 2004: 0,613 kg CO2/kWh

** electricity tariff 0,14 €/KWh incl. 3,592 ct/KWh EEG-allocation

Rexroth Sytronix solution

• 4.0 kW motor

• Variable speed pump drive Sytronix

• 6cc internal gear pump

• Return line filter/cooler

Energy consumption 13.620 kWh/Yr

– 45 % Savings 10,980 kWh/Yr

1,537 €/Yr **

CO2-prevention* 6.7 tons/Yr

source: www.sw-machines.de

Energy

on Demand

Efficient

Components

Energy

System Design

Sytronix FcP 5000

Conventional drive solution:

• 5.5kW motor

• Control pump 250 bar / 13 l/min

• Fixed displacement pump for filter/cooler

Energy consumption 24.600 kWh/Yr



Application example – Die Casting Machine

23

Conventional solution:

Constant speed drive

(11 kW motor) with fixed

displacement pump

Advanced solution:

Rexroth SvP variable-speed

pump drive

50 to clamp force

7.5 s cycle time

Energy consumption:

10.1 kW 1.7 kW Energy saving

83.2 %



Application example – Rubber Injection Machine

24

Conventional solution:

Constant speed drive(15 kW

motor, load sensing) with

SYDFE pump

Advanced solution:

Rexroth SvP variable-speed

pump drive

50 to clamp force

7.5 s cycle time

Energy consumption:

2.9 kW 0.8 kW Energy saving

72.3 %



Sytronix SVP 7000 Application

25

Requirements

Equip both hydraulic axis with controlled servo

variable pump drive (SvP)

Use existing interfaces

Machine Information

Press brake 135t

cycle time: 15sec

Press Brake




26

PLC

U x

U x

PLC

Safety control

power unit

Control block

with safety

functionality

Control block Control block

U x

U x

U x

Control block

with safety

functionality

Press Brake – Conventional Solution HMI




27

Press Brake – New Solution

Servo motor MSK

Digital servo drive HCS02

Axial piston pump A10

(4-quadrant)

Control block w/ switching

and safety valves

HMI

PLC

U x

U x

PLC

Safety control

Control block

with safety

functionality

Control block Control block

U x

U x

U x

Control block

with safety

functionality




28

Press Brake – Positioning Accuracy Conventional System SvP System A10 (6ccm)

(zoom of target position) (zoom of target position)

Fast Advance

hold time

Forming speed

fast return




29

Press Brake - Energy Consumption

t [s]

P[k

W] / E

[Wh]

axis position

power energy

SvP System A10 (6ccm)

x [m

m]

5 10 15

0

10

20

30

40

50

60

5 10 15-100

0

100

200

300

400

t [s]

P[k

W] / E

[Wh] axis position

power

energy

Conventional System

x [m

m]

Maximum electric power:

19kW 22kW

Total energy per cycle:

32,6Wh 19,2Wh

Stand-by power:

1,85kW 0,55kW

• Energy savings approximately 40% for typical press cycle




30

Energy efficient system design

Efficient components

Energy recovery

Energy on demand

Thank You




Jan Komsta

Tel: 610-694-8547

Mobile: 610-216-9034

[email protected]

www.boschrexroth-us.com

www.boschrexroth.com/sytronix




Application example: Ingersoll CM Systems, S-8255

Speed Variable Pump Drives Technology

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