faculty of mechanical engineering chair agricultural systems and...

Electrical drive train for combine headers

Elektrifiziertes Antriebssystem für Getreideschneidwerke

Steffen Wöbcke, Thomas Herlitzius

P. Hornberger, N. Michalke, F. Mörtl, M. Müller, U. Schuffenhauer, J. Seyfarth

Faculty of Mechanical Engineering Chair Agricultural Systems and Technology

VDI-MEG Kolloquium Mähdrescher, Hohenheim, 12./13.September 2013

September 12, 2013 VDI-MEG Kolloquium Mähdrescher Slide 2

I. Introduction and description of initial state

II. Objectives of electrifying a combine header

III. System design

IV. Benefits of electrified headers

V. Summary and outlook

Content


� requirements of global market are increasing productivity with decreasing harvesting costs and increasing profitableness

� in past meeting requirements by

� improving functionality

� increasing diesel engine power

� increasing harvesting ground speed

� increasing header width

proposition:

continuing increasing combine productivity by

� using function-specific, distributed, modular designed drives

� new drive concepts, optimized in available space, energy-efficiency

� automation of operating sequences

Introduction

image source: Zürn


Initial state

knife

lateral knives

feeder belts

reel

intake auger

image sources: ACGO, Claas, Geringhoff

main header assemblies� knife� intake auger� reel� feeder belts (optional)� lateral knives


� knife:� belt, gearbox with shafts or hydraulic motor, cutting width > 9 m: divided cutterbar with two-

sided drive, fixed speed� intake auger:

� chain or gearbox and overload clutch, one-sided drive, fixed speed� reel:

� hydraulic motor or belt variator, one-sided drive, variable speed� feeder belts (optional):

� chain, fixed speed� lateral knives:

� hydraulic, electrical or mechanical

Initial state

image sources: Claas, Geringhoff, Zürn


reel intake auger knife intake belts

variability of speed

available - - -

separate reversing

- - - -

adjustable torque limits

- - - -

sensor systemn [min -1], M [Nm]

- - - -

Objectives of electrifying combine headers


reel intake auger knife intake belts

variability of speed

available desired desired desired

separate reversing

desired desired - desired

adjustable torque limits

desired desired desired -

sensor systemn [min -1], M [Nm]

desired desired desired desired

Objectives of electrifying combine headers

� technical solution meeting demands best: electrical drives


experimental model: header Zürn 640 PF 40 ft (12 m)� knife:

� belt with planetary drive, two-sided drive, fixed speed� intake auger:

� chain drive and friction clutch, one-sided drive, fixed speed� reel:

� hydraulic motor, middle drive, variable speed� feeder belts:

� 8 belts� chain drive, one-sided drive, fixed speed

� lateral knives:� mechanical

drives in combine header

knife intake auger feeder belts lateral knivesreel

Experimental platform

image source: Zürn


component speed [min-1] torque [Nm] power [kW]

knife 600 250 15,7

reel 40 1500 6,3

intake belts 385 120 4,8

intake auger 260 1000 27,2

lateral knives 550 17 1

sum 55,0

Nominal power requirements40 ft header for dimensioning

image source: Zürn


closed system of generation, transformation, storage, transfer and management� standard connection to combine:

� drive shaft� electric / CANBUS

� own generator on header� DC link� own cooling circuit

Design of electrical system


electrical system on header

� voltage level 58 V DC in DC link (extra low voltage, below threshold of 60 V)

� advantages:

� no additional safety equipment required (e.g. insulation monitor)

� legal regulations: even no protection against creature contact necessary

� reduced effort for EMC

� disadvantage: higher dimension of cable cross-section

image source: Compact Dynamics



� knife:� divided cutterbar with 2 drives� variable speed

� intake auger:� two-sided drive, 2 electric motors� partly integrated in auger� variable speed

� reel:� one-sided drive, 1 electric motor� partly integrated in reel� variable speed

� feeder belts:� 8 belts� every belt with own electric motor� partly integrated between belts� variable speed

� lateral knives:� left and right side� mechanical drive� alternative electric motors




technical data of main usedelectric machine Dynax in header

inverter 3-phase inverter integrated

voltage DC 42 V – 58 V

power (continuous) 20 kW (at 58 VDC)

power (maximum) 25 kW (at 58 VDC)

torque 75 Nm (up to 3000 min-1)

maximum speed 10.000 min-1

cooling water / glycol

weight 14 kg

174 ∅ 250

242

speed [1/min]

torq

ue [N

m]

efficiency of motor and inverter

number of Dynax machines in header:� generators (3)� intake auger (2)� reel (1)� knife (2)




challenges of function-specific, distributed, modular designed drives� in comparison to all-mechanical drives specific loads become more important � removal of inertia� decoupling of diesel engine’s and combine’s inertia system

� linear sinusoidal trajectory of cutterbar and load cycle of electric motor� simulation provides conclusions for

� dimensioning and design of drive system� strategy for control� mechanical loads� power distribution

-1

-0,5

0

0,5

1

0,25 0,3 0,35 0,4 0,45 0,5

F*

/Fm

ax

, P*

/Pn

t in s

linear force and drive power

F, variant 1

P, variant 1

F, variant 2

P, variant 2


-1,0

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

1,0

0 10 20 30 40 50 60 70 80

stroke [mm ]

M/M

max

forward stroke - acceleration forward stroke - deceleration

return stroke - acceleration return stroke - deceleration


� additional benefit caused by advantages of electrical drives

� decentralized drives are mostly integrated into functional elements

� reduced space demands especially in side panel sections

� enhanced maneuverability at barriers and headland

� reduced crossing crop and reduced header losses

� advantages of electrical drives in headers:

� variable speed

� absolute value

� direction

� adjustable torque limits

� integrated measurement of current and voltage

� calculation of speed and torque possible

Benefits of electrified headers I

image source: Zürn


� homogenized crop flow in header and in combine

� increased feedrate of combine at constant loss level

� reduced cleaning and separation losses at constant feedrate

� generation of feedrate related signal for feedrate control of combine

� reduced wear and tear of drives and functional elements

� reduction of maintenance

� reduced costs

Benefits of electrified headers II

image source: Wikipedia


� opportunity of separate reversing functional elements

� fast removal of jamming crop

� reduced machine downtime and increased combine performance

� condition monitoring of functional elements

� generation of load cycles

� maintenance interval load-dependent instead of time-dependent

� reduction of maintenance

� reduced machine downtime

� reduced costs

Benefits of electrified headers III

image sources: Schumacher, agrartechnik-im-einsatz


new form of power-train management system

� semi-automated header functions

� reduced excessive demands of operator, especially

� homogenizing crop flow in header and in combine

� fast removal of jamming crop

Benefits of electrified headers IV

image source: John Deere


Challenges of electrified header

challenges of electrical drive system in combine headers

� costs of electrical drives

� complexity

� generating electrical energy

� EMC

� cooling system

� …

� dynamic loads

� reliability of electrical components in field

� …


� configuration of combine header with electrical drives

� generation of electrical energy with generators on header

� independent electrical and cooling system with same standard connection to combine as conventional headers

� drive train as decentralized architecture with torque and speed as degrees of freedom

� enhancement of functionality

� new strategies of power-train management system

� semi automated sequences possible

Summary

image source: Zürn


� currently experiments on test stand

� field tests in season 2014

� statements to technical feasibility and suitability of electrical drives in

combine headers in field

� determination of power requirements and power distribution with

available information as torque and speed

� load cycles can be deviated

� evaluation of additional benefit

� estimation of economic feasibility

Outlook


Thank you for

your attention!

website of project:

www.eharvest.eu

faculty of mechanical engineering chair agricultural systems and...

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