Design of a High Voltage System for Agricultural...

Design of a High Voltage System for Agricultural Machines

Wolfgang Breu 25. / 26. Juni 2013

Fendt Advanced Engineering

4. Kolloquium Elektrische Antriebe in der Landtechnik 25. - 26. Juni 2013 BLT Wieselburg, Wolfgang Breu

1

Agenda

AGCO History Higher Voltage Electrification 1

Challenges 3

4 Current Status

Motivation 2

5 System architecture

6 System costs

7 Statements


AGCO History of Higher Voltage Electrification

2001 Start of MELA research project

Development of compact 140 kW PSM electric machine

Development of suitable power electronics

Safety concept

Electrical - mechanical power split CVT

2009 first common discussions with competitors

Common interface for agriculture industry is required

2010 Presentation AGCO E-Rogator

Self-propelled sprayer with electric four wheel drive

2011 Cofounder of AEF High Voltage Group 7

Working sample of an interface up to 150 kW

2


3

Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


Comfort enhancement due to simplified operation for the driver

New functions and technologies

PTO hits complexity and power limit

Hydrostatic drives are worse in efficiency and controllability

Precise automation

Higher efficiency of complete system

Yield increase, decreasing usage

of chemical substances

Process enhancement

Motivation

4


5

Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


Challenges

Generation of electric power on a higher voltage level

• 700 V DC link

• Additional installation space required

Cooling of electronic components

• Additional cooler

• Flow temperature T < 65°C

Safety

• Current is not visible, can cause serious hazards monitoring/diagnostics required

System costs

• Electric components are additional equipment higher general costs

Service

• Service personnel is not trained training requirements

6


7

Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


Current Status: Electrification in Agricultural Industry

Several prototypes have been build up and were tested under

field conditions

Necessary key components – motors and power electronics are available in different power levels in meantime

Target prices of 30 to 60 € per kW electrical power

(motor and power electronics) are achievable according to supplier-statements

Positive impressions and experiences clearly predominate

Further electrification projects of different manufacturers are

planned or already in progress

8


9

Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


AGCO System Architecture

10

700 V DC - link

DC/AC

DC/AC

Interlock – Safety Monitoring

Cooling

ISOBUS - Communication

ECU ECU

DC/AC

AC/DC


Safety concept

11

IT - System

Isolation monitoring (including implement)

Permanent monitoring of electrical connection and power supply

Double insulated system

Emergency shut down


625 nF

12

2

electric drive class II

AC

DC

Cy Cy

Cpar

1/Ctotal class II=1/Cpar+1/(2*Cy)

electric drive class I

Ctotal class I=2*Cy+ 2*Cpar

AC

DC

Cy Cy Cpar Cpar

IEC protection class I vs. protection class II

example: 140 kW generator/motor C total class I = 280 nF

C total class II = 10,8 nF (values needed to fulfill EMC regulations)

280 nF

10,8 nF


Tractor implement

pump P1 (p, Q)

cooling power approx. 10 % generated power

heat exchanger PWT (p, Q)

pump P2 (p, Q)

component c

component a component b

Component x motor/electronic etc…

5 Cooling System: Tractor with implement

Narrow DT (45°C ambient temperature and 65°C flow temperature)

Complex in comparison to hydraulic system:

harness for current and tubes for cooling fluid


14

Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


System costs

Tractor side:

• Cooling system additional

• Generator additional

• Converter additional

• High voltage harness additional

Implement side

• Substitution of mechanical or hydraulic drives replacement (first prototypes)

• New machine concepts not available yet

System costs will rise in first series, especially on tractor side

Intelligent solutions on implement side are essential

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Availability of components

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Electric motors

• A lot of different technologies in different sizes at different costs available

• Rapidly ongoing development of various motor technologies over the last years

• best motor technology is application specific, selection requires experience

• Goal: 20 - 40 €/kW in series (depending on torque and speed)

Power Electronics

• More and more inverters for mobile machines are available

• Costs are already coming down

• New developments in progress, new concepts in the pipeline

• Goal: 20 - 40 €/kW in series (depending on technology/electric motor type)


Costs of key-components

17

electric motors (exemplary)

inverters (exemplary)

Power [kW]

Speed [rpm]

Technology

Costs [€]

pcs/year €/kW Cooling

13 5000 PSM 450 5000 35 Air

20 5000 PSM 600 5000 30 Air

12 3500 SR 300 5000 25 Water

Power [kW]

Voltage [V]

Costs [€]

pcs/year €/kW Cooling

2 x 10 700 DC 972 10.000 49 Water

2 x 20 700 DC 1632 10.000 41 Water

15 700 DC 445 5.000 30 Water/Oil

Data based on quotes of several potential suppliers


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AC 1) DC 2)

Electric motor technology ASM, PSM ASM, PSM, SR, other 3)

Inverters - 2 x 300 €

Interface 2 x 200 € 1 x 100 €

harness 4) 2 x 250 € 1 x 150 €

total 900 € 850 €

1) AC inverters on tractor, 2 AEF interfaces required

2) DC inverters on implement, single DC-only interface 3) motor motor technology: can be selected individually

4) harness - 50 €/m @ 5 m special cable (power lines,

lower and higher voltage, bus-system) in AC case - 30 €/m @ 5 m series cable in DC case

Example: electric driven implement (2 motors, 10 kW each)


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Agenda


Challenges 3

4 Current Status

Motivation 2


6 System costs

7 Statements


20

700 V DC - link

DC/AC

DC/AC

Interlock - Sicherheitsüberwachung

Kühlung

Isobus - Kommunikation

ECU ECU

DC/AC

AC/DC

One DC Power Interface Best practice for future concepts.

One communication interface ISOBUS standard.

Implement Drives cooling available if necessary.

Key components will be affordable within the next couple of years.

A compact, cost effective DC-only interface has to be developed.

New partners are welcome to join and work with us at the AEF.

Statements


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Thank you for your attention!

Design of a High Voltage System for Agricultural...

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