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Patent Searching and Data


Title:
HOUSING FOR ELECTRICAL COMPONENTS ON A VEHICLE
Document Type and Number:
WIPO Patent Application WO/2012/084633
Kind Code:
A1
Abstract:
A voltage supply system on a vehicle, said system comprising a housing (3a) containing at least two electrical components for the generation of a voltage supply.

Inventors:
BREU WOLFGANG (DE)
HONZEK ROBERT (DE)
SZAJEK ANDREAS (DE)
Application Number:
PCT/EP2011/072719
Publication Date:
June 28, 2012
Filing Date:
December 14, 2011
Export Citation:
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Assignee:
AGCO INT GMBH (CH)
BREU WOLFGANG (DE)
HONZEK ROBERT (DE)
SZAJEK ANDREAS (DE)
International Classes:
B60K6/445; B60R16/03
Foreign References:
EP0901924A11999-03-17
EP1981081A12008-10-15
US20090206662A12009-08-20
US20100072865A12010-03-25
US20040226761A12004-11-18
US5242278A1993-09-07
DE19714227A11998-10-15
Other References:
None
Attorney, Agent or Firm:
SMITH, Louise (Kenilworth Warwickshire CV8 2TQ, GB)
Download PDF:
Claims:
Claims

1. A voltage supply system on a vehicle, said system comprising a housing containing at least two electrical components for the generation of a voltage supply.

2. A voltage supply system on a vehicle as claimed in claim 1 wherein the

voltage supply is greater than 400 V.

3. A voltage supply system as claimed in claim 1 or claim 2 wherein the

housing contains a generator.

4. A voltage supply system as claimed in any preceding claim wherein the housing is provided with more than one compartment.

5. A voltage supply system as claimed in any preceding claim wherein a part of the housing is placed behind a combustion engine on the vehicle.

6. A voltage supply system as claimed in any preceding claim wherein a part of the housing is provided with a heat shield.

Description:
Housing for Electrical Components on a Vehicle

This invention relates to a housing for electrical components on a vehicle. More specifically, this invention relates to a housing for electrical components on an agricultural machine.

It is known to generate electrical energy on a vehicle for powering propulsion systems. For example, electric motors are used to drive the wheels on a vehicle, such as a truck or car. To provide the necessary electrical energy, the vehicle is provided with a rechargeable battery, a fuel cell and a combustion engine connected to a generator.

Typically, such a vehicle will additionally have an internal electrical network (usually 12V or 24V DC) for supplying components on the vehicle and/or external systems, e.g. on a towed trailer, for example lights.

Agricultural machinery, such as agricultural tractors have different electrical energy requirements than passenger vehicles. As well as travelling over ground, a tractor must also provide power to implements attached to the tractor such as trailer, balers or ploughs. The implements require power to drive certain components on the implement, such as drives. The drives are usually powered by the PTO, or a hydraulic circuit.

If a medium voltage supply system, that is a voltage supply greater than 400 V (150 kW) is available on the tractor, it is desirable to supply implements attached to the tractor with electrical energy. Electrical motors are cheap and easy to control and if the energy supply for the implement is taken from the tractor it avoids the implement having to generate and store its own electricity. In order to supply a medium voltage on a tractor, additional components need to be installed on the tractor: generator, battery or fuel cell, a power electronic unit, monitoring systems, AC/DC converters, DC/DC converters, a brake chopper control, electric ian drive and associated control, an electric PTO and associated control and electrically driven pumps.

All these components will be supplied with a voltage generated and stored by the generator, a rechargeable battery, or a fuel cell. Since high voltages are dangerous, the wiring between components must be secure so that it can not be damaged by debris or unintentionally contacted by humans. The components must however be easily accessible for repairs and maintenance.

Medium voltage components require cooling systems to keep the temperatures of the electrical components at an optimum working temperature. Cooling circuits therefore have to be provided to cool electrical components on both the tractor and implement. Additionally, cooiing requirements of electrically driven components on the tractor may be very different so a cooling supply/circuits/pipes may be widely spread over the tractor .Such cooiing circuits can be cumbersome and are also subject to damage by debris and unintentional human contact.

It is an aim of the present invention to provide a housing for electrical components for use on a vehicle. The electrical components are used to generate a voltage supply on the vehicle greater than 400V. The housing offers easy access to the

components and assists in the cooling of the components whilst increasing the personal safety of the vehicle operator.

According to the invention there is provided a voltage supply system on a vehicle, said system comprising a housing containing at least two electrical components for the generation of a voltage supply.

Preferably, the voltage supply is greater than 400V. Preferably, the housing houses a generator. More preferably, the housing is provided with more than one

compartment. The housing may be situated behind a combustion engine on the vehicle. The housing is preferably provided with a heat shield

The invention will now be described, by way of example only with reference to the following drawings in which:

Figure 1a shows a side view of an agricultural tractor,

Figure 1 b is a perspective view of a chassis of a tractor showing the electrical housing in accordance with the invention,

Figure 2 shows a circuit diagram for a medium voltage supply on an agricultural tractor.

Figure 1 shows an agricultural tractor 1 having a combustion engine 2 and a medium voltage supply 3. By the term medium voltage supply, it is meant voltages over 400 V. The electrical components needed to generate and store the medium voltage supply are described in figure 2 and are housed within housing 3a which is mounted on a tractor frame/chassis 4.

Housing 3a is a solid, closable box structure made from cast which completely surrounds the electrical components. Housing 3a may be covered with an insulating material. The housing 3a further houses a cooling circuit 5 to cool down the electrical components within the housing. Housing 3a is accessible by opening cover 3b.

Cover 3b may be equipped with or activate a switch to stop the engine and/or electric voitage when the cover 3b is opened. This protects operator from coming into contact with medium voltage greater than 400 V.

The housing 3a may be divided into several parts or compartments which may be accessed by associated hinged covers.

A protective wall 6 is positioned between engine 2 and housing 3a to protect the housing 3a from heat impact caused by engine 2 and related air streams.

It is also possible that the housing 3a is integrated into the chassis of the tractor.

By having the electrical components in one confined area within housing 3a, the cooling circuit 5 can cool the components more efficiently than if the components are spread out in different locations on the tractor. Since the components are enclosed within the housing they are protected from damage by debris and humans and there is smaller risk of personnel accidentally receiving injury from the components. If any of the electrical components in the housing breakdown, or are faulty, the whole housing complete with components can be easily lifted from the chassis and sent for repair.

In addition, by having the electrical components in one confined area within housing 3a it is easier to fulfil the requirements for ensuring electromagnetic compatibility (EMC). Since all the electrical components within the housing are potential electromagnetic disturbing sources, the housing 3a itself provides a shield, or at least a base for mounting a shielding structure thereto.

Figure 2 shows a suitable circuit diagram for supplying a medium voltage supply on the tractor. The medium voltage supply unit 11 within housing 3a comprises an electric generator 11a driven by the engine crank shaft 10a of combustion engine 10 and an electronic power unit 11b (insulated-gate bipolar transistor) connected to the electric generator by wiring.

The generator produces AC power with an AC frequency dependent on the combustion engine speed. The electronic power unit 11 b converts the AC power output of the generator 1a to a DC voltage with the defined DC-link voltage level to provide all units connected to the DC network 1 e.

A brake chopper 11 c is provided to avoid a voltage rise in the DC network 1 1e if energy is fed back into the system from other sources than the generator. The chopper comprises an oscillating switch in series with a resistor and, depending on the input voltage overshoot (coming from e.g. the implement via the internal network) the switch is oscillated to guide the excess voltage into the resistor transforming the voltage into heat. The oscillation is necessary to keep the network active and supplying energy. If the switch was to be closed completely over a longer period, the complete voltage supplied by the system would be destroyed and all consumers would be non operative. By oscillating the switch, only the peaks of the voltage are destroyed and the system is still operative. In addition, the resistors are generally designed to be quite small so they are not capable of receiving a constant high load. Using oscillation enables them to cope with the load. E.g. the nominal voltage of the network is 700 V. The overshoot limitation is 900 V. If peaks greater than 900 V occur the switch is closed in an oscillatory manner.

An insulation monitoring system 1d is provided to monitor the resistance in the network to detect electrical malfunctions in the medium voltage system. This is necessary to protect the life of potential users of the system and to prevent damage in electric components of the tractor or implement or other consumers connected to the system.

Internal medium voltage DC network 11e (greater than 400V, 150 kW) is provided for supplying tractor components such as a battery/supply network 16 via DC/DC converter 16a reducing a voltage greater than 400 V to, for example, the standard 12V supply.

An electronic unit 11 g comprising a heating/ventilating/air conditioning (HVAC) compressor via DC/DC converter is also provided. Similarly a variable cooling fan drive 1 1f is supplied via a DC/AC inverter to provide a variable frequency to vary fan speed. To supply external consumers (e.g. on implements/ front loaders /stationary devices supplied by the tractor) additional supply means are provided.

Internal medium voltage DC network 1 1e is connected to an electronic unit 11 h for supplying external consumers:

In a first mode, electronic unit 11 h converts high power DC into high power AC at fixed frequency to connectors 11 i. Alternatively electronic unit 11 h can also supply high power DC to connectors 1 1 k. By having an DC or AC supply, different consumer requirements can be fulfilled. E.g. an electric motor running on constant speed can be supplied with AC at a fixed frequency adequate for the wanted motor speed. If one or more electric motors with variable speed must be supplied, it may be more efficient to supply DC and convert into AC on the implement respectively for every electric motor. Connectors 1 1 i and 11 k are attached to the rear or front of the tractor 1 to be connected to an implement, outside medium voltage supply unit 11.

There are two internal cooling circuits 111 and 11 m. First internal cooing circuit 111 carries transformer oil and is used to cool high performance components, for example electric generator 1 1a and electric power unit 11 b. A second internal cooling circuit 1 1 m carries a water glycol emulsion and is used to cool lower cooling requirement components such as a battery/supply network 1 1f, HVAC compressor supply 11g, cooling fan drive supply 1 1f and electronic units 11 h.

By having two separate cooling circuits, different consumers with different cooling requirements can be efficiently cooled.

Alternatively, cooling circuits 1 ! and 1 1 m may be merged into one cooling circuit, if components with similar requirements are to be cooled. Nevertheless, the necessary network of pipes and tubes for cooling is reduced by having all the components in a confined area within housing 3a.

Alternative embodiments of the circuit diagram shown in Figure 2 are described in the applicant's pending UK patent application, filed under reference No. GB10044GB