WO2016055181A1

WO2016055181A1 - Method for controlling a system for inductive energy transmission

Info

Publication number: WO2016055181A1
Application number: PCT/EP2015/067242
Authority: WO
Inventors: Joerg Mecks; Steffen Eppler
Original assignee: Robert Bosch Gmbh
Priority date: 2014-10-07
Filing date: 2015-07-28
Publication date: 2016-04-14
Also published as: DE102014220265A1

Abstract

The invention relates to a method for operating an inductive charging device for a vehicle, wherein the vehicle has at least one secondary coil in the vehicle underbody, wherein at least one magnetic field sensor for measuring a magnetic field of the inductive charging device is arranged on an outer vehicle line or between the outer vehicle line and the secondary coil, wherein in a first step the charging power of the inductive charging device is throttled if the magnetic field of the inductive charging device measured by means of the magnetic field sensor exceeds a specified limit value.

Description

Description title

Method for controlling a system for inductive energy transmission State of the art

The increasing spread of vehicles with an electric motor as

Drive unit and a battery as energy storage for the electrical energy in the vehicle requires a convenient solution for the

Recharging the battery. Usually, in a parked vehicle, the accumulator is physically connected to an external power source by means of a charging cable, which is referred to as conductive charging. However, such an approach requires the driver's involvement in charging, which is considered inconvenient due to the hitherto necessary frequency of charging, and therefore complicates broader market penetration of such systems.

Instead of the conductive charging, the inductive charging represents an innovative

Solution for charging the energy storage of electric vehicles. The inductive charging advantageously requires no involvement of the driver for charging, it provides protection against the weather and charging is safe against unwanted external influences. Here, typically, the primary coil of the transformer is either embedded in the street floor or designed as a floor-mounted pallet and is connected by means of suitable electronics to the power grid. The secondary coil (or passive coil) of the transformer is typically fixedly mounted in the underbody of the vehicle and in turn connected by means of associated power electronics with the vehicle battery or the energy storage. For energy transmission, the primary coil generates a high-frequency magnetic alternating field, which penetrates the secondary coil and in this a corresponding current induced. Since, on the one hand, the transmittable power scales linearly with the switching frequency, and on the other hand, the switching frequency is limited by the control electronics and losses in the transmission path, a typical result

Frequency range from 30 to 150 kHz.

The inductive energy transfer takes place via the air gap between the two coils. In this case, the primary coil is arranged below the vehicle, typically in or on the ground, whereas the secondary coil is arranged in the vehicle. In order to realize the most efficient energy transfer, the highest possible coupling between the two coils must be achieved, which equates to minimizing the stray field.

Due to physical laws, the losses increase with increasing coil spacing and the efficiency is reduced. In order to realize a high efficiency and at the same time to reduce the energy losses, therefore, the primary and secondary coils must be optimally positioned to each other, that is, both in terms of the height distance and the offset in the plane. Optimal would be a concentric arrangement of the two coil at the same time a very small distance in the height direction.

Experience has shown that it is hardly possible for a driver without additional aids to fulfill these requirements with regard to the positioning of the two coils when the vehicle is parked or parked in a targeted and reproducible manner, in particular with regard to the offset in the plane.

The attachment of the secondary coil on the vehicle can be done at different locations, such as on the vehicle roof, on the license plate, under the vehicle or in the area of the subsoil. In general, the positioning of the secondary coil under all

Vehicle preferred due to the least possible impact on selbige in the event of an accident. Furthermore, the interior of the vehicle must be shielded from the inductive energy transfer to the secondary coil resulting magnetic fields, which is why usually the

Vehicle underbody with a sheet of non-magnetic material, preferably of aluminum, shielded to prevent a possible negative influence of these magnetic fields on the persons in the vehicle.

An approach for a contactless energy transfer is described in DE 10 2010 053 058 AI, which is a motor vehicle device for an electric and / or hybrid motor vehicle with a charging unit, which has a power transmission unit for charging a battery device, which is for a contactless

Power transmission is provided, and with a positioning unit, which is intended to position the electric and / or hybrid motor vehicle autonomously for a charge, and having at least one guide coil, which is provided for determining a position of the electric and / or hybrid motor vehicle thereto to receive an inductive contact to an inductive guide element of a charging device.

The extent of the high-frequency magnetic alternating field between the primary and the secondary coil (and thus the local field strength) depends, among other things, on the transmission power, frequency, the

Coil spacing, coil offset, coil geometry,

Shielding measures, etc. from. In the range of very high field strengths, which occur in the direct air gap between primary and secondary coil, the alternating magnetic fields in metallic objects can induce electrical eddy currents and thereby heat them unacceptably. This heating represents a danger not only for personal safety but also for the operational safety of the vehicle. A necessary component of an inductive charging system (or system for inductive energy transmission) is to detect metallic objects located in the air gap ("foreign object detection"). and then bring the energy transfer to a safe state by reducing power or completely shutting off the transmission. In addition to the direct danger from heated metallic objects, must protect the

Public the valid limit values for electromagnetic fields are kept (eg ICNIRP). As a public, different zones can be defined in, on or around the vehicle. Current state of the art is that there are various limits for the electromagnetic fields present in inductive charging worldwide.

The permissible limits are still under discussion, but it is expected that an agreement on a limit in the context of a

Standardization can be achieved.

Since inductive charging is a new technology, it can not be ruled out that limits will be subject to further changes in the future or that these limits may differ locally and regionally. For operation in semi-public or safe areas (e.g.

Parking garage) could also be allowed significantly higher limits, as a direct threat to living things is not present.

Inductive power transmission systems are currently being designed to accommodate a specific vehicle type (with specific wheelbase, distance between coil and vehicle rim, underbody construction, shielding, ground clearance) as well as maximum transverse offset to primary coil (eg: + / ^■ 15 cm

Positioning offset in longitudinal / lateral direction) the limits for the magnetic stray fields in the vehicle or in the vehicle environment are met.

The disadvantage is that the structural conditions, however, are different from vehicle to vehicle. This requires a lot of effort and hinders a possible standardization which in turn is disadvantageous. Thus, for standardization, it is imperative that different vehicles can be loaded on one and the same baseplate where the primary spool is located, so that a small short wheelbase car with a narrow track is also above the System can be loaded like a large sedan with a long wheelbase and wide track

It is therefore an object of the invention to provide an improved method for controlling a system for inductive energy transmission or an inductive

Specify charging system, with the limits for electromagnetic

Stray fields in various areas in and around the vehicle to be loaded are observed in a controlled manner, the procedure being of loading

Vehicle type is independent. Disclosure of the invention

The inventive method for operating an inductive energy transmission system with the characterizing part of claim 1 has the advantage that with him the limits for stray electromagnetic fields in different areas in and around the vehicle to be charged are met, the method of the vehicle to be loaded type independently is.

For this purpose, the invention provides that in the method for operating the system for inductive energy transmission for a vehicle having at least one secondary coil and at least one magnetic field sensor for measuring a magnetic field of the inductive charging device on a

Vehicle outer line or between the vehicle outer line and the secondary coil has, in a first method step (A), the charging power of the inductive charging device is throttled when the measured magnetic field with the magnetic field of the inductive charging device exceeds a predetermined limit. By the arrangement of at least one

Magnetic field sensor in the vehicle outer line or between the

Outside the vehicle and the secondary coil, the limits for stray electromagnetic fields in various areas in and around the vehicle can be controlled. When operating the system, the magnetic field is first controlled to a maximum allowable limit. Is based on the at least one magnetic field sensor on a

Is arranged outside the vehicle or between the vehicle outer line and secondary coil, exceeding the allowable limit measured (for example, impermissibly high stray fields), the charging power of the inductive

Charger throttled accordingly. This advantageously ensures that systems for inductive energy transmission (primary as well

Secondary side) can be designed vehicle-unspecific, the

Development effort is reduced and interoperability across diverse

Vehicle classes is ensured.

An adaptation to new limits - e.g. updated national or

international standardization - can thus be easily achieved through software become. It is also possible to comply with various limit values depending on the security area (public space, secured garage, etc.). This only requires the transmission of the locally valid maximum limit value to the vehicle. Furthermore, it is advantageous that the implementation of the mentioned in claim 1

Method allows operation at the maximum power limit, whereby the shortest possible charging time is achieved. If several vehicles are charged inductively, the permissible limit value can be exceeded in the area between the vehicles due to superposition of the individual fields. By direct measurement of the resulting absolute field, an excess can be prevented and the energy transfer of one or more vehicles can then be reduced accordingly. The limit, which leads to throttling the charging power when exceeded, can be advantageously set by the end user himself for his individual charging. This can be this

Limit value only below the limit prescribed in the standardization. The user can thus his device in a personal

Operate "low emission mode" (UCX).

The measures mentioned in the dependent claims advantageous refinements of the method specified in the independent claim are possible.

Advantageously, the magnetic field sensor is installed in an exterior mirror of the vehicle. The exterior mirror is located on the outside of the vehicle and is preferably installed on the driver and passenger door. A vehicle occupant or passerby usually approaches the car in the area of the vehicle doors and would be exposed there to health-threatening stray fields.

In a further advantageous embodiment of the method, the at least one magnetic field sensor is installed in a parking sensor of the vehicle.

Parking sensors are usually installed in the front or rear bumper and thus mounted in the outline of the vehicle. It is therefore appropriate to the same place / position the at least one magnetic field sensor position it at the maximum distance from the secondary coil

Magnetic field or stray field to detect.

According to a further embodiment of the method, the at least one magnetic field sensor is installed in the interior of the vehicle. Due to the arrangement in the vehicle interior use during loading would be conceivable while driving. Thus, the resulting during charging electromagnetic

Stray fields are limited so that the occupants during this dynamic loading (charging while driving) no health risk.

Furthermore, it is advantageous that the vehicle is repositioned in a further method step (B). Is in the first process step a

Exceeding the limit value of the measured with the magnetic field sensor

Magnetic field detected, the u.a. The reason for this is that the vehicle is positioned incorrectly and optimal energy transfer is not possible. The resulting stray fields can be outside the tolerable limits. Accordingly, it is advantageous to make a repositioning of the vehicle.

In a further advantageous embodiment is in another

Process step (C) at least one active element for controlling the

Magnetic field actuated. By active elements such as e.g. further coil systems (multicoils) or ferrites it is possible to influence the electromagnetic field forming during the charging process, so that e.g. the maximum permitted limit can be met, but in areas that are accessible to living beings (persons, animals, etc.), there is no risk to health.

In a further advantageous embodiment, the inductive charging system is designed as a multi-coil system, wherein at least one coil this

Multi-coil system as needed in a further process step (D) additionally switched on or off. The multi-reel system thus enables the Forming a magnetic field adapted individually to the present vehicle geometry of the vehicle to be loaded.

Advantageously, the driver or owner of the vehicle is informed in a further method step (E) if an excess of the limit value of the magnetic field is detected. This serves as a warning against any potentially harmful magnetic fields.

Furthermore, in a further advantageous embodiment, a

External monitoring in a further method step (F) activated, with which it can be monitored whether a living being (animal or person) is in the immediate or immediate vicinity of the vehicle. Is by means of

External surveillance found that currently no living thing in the

Therefore, it is advantageously possible to charge the vehicle inductive and thereby accept stray fields, which in

Presence of existing living things would not be allowed.

Advantageously, each of the said further method steps (B) to (F) can be carried out according to the method step (A) mentioned in claim 1. A fixed sequence is advantageously not necessary.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the invention.

Brief description of the drawings

Fig. 1 shows in schematic form a side view of a motor vehicle with a system for inductive energy transfer;

Fig. 2 shows in schematic form a plan view of the motor vehicle of Fig. 1 from above Fig. 3 shows in schematic form a representation of the invention

Method for controlling the system for inductive energy transmission

Embodiments of the invention

FIG. 1 shows a vehicle 10 which is parked above an inductive charging system 11 or a system for inductive energy transmission 11. The vehicle 10 is thereby turned off so that the secondary coil 14 or receiving coil 14 of the vehicle 10 is arranged above the primary coil 23 or transmitting coil 23. Due to the required ground clearance of the vehicle 10, there is a gap 24 between the terrain in which the primary coil 23 is disposed and the vehicle floor 13 of the vehicle 10 in which the secondary coil 14 is located.

After the vehicle 10 has been parked with the secondary coil 14 in the vehicle 10 over the primary coil 23, the charging of the traction battery 25 (not shown) may begin. For this purpose, the primary coil 23 generates an alternating magnetic field. This alternating magnetic field is absorbed by the secondary coil 14 and into electrical energy

transformed. This electrical energy is then available via a suitable circuit 26 (not shown here) for charging the traction battery 25. The secondary coil 14 does not necessarily have in

Vehicle floor (vehicle underbody) 13 of the vehicle 10 to be installed.

It is also conceivable on the side, the front, the rear or the roof of the vehicle 10 arranged secondary coil 14. In the vehicle 10, at least one magnetic field sensor 12 is installed, which is preferably in the

Vehicle outer line 15 - ie the outermost boundary of the vehicle 10 (vehicle outer shell) - is arranged. The magnetic field sensor 12 is preferably used in the exterior mirrors 16, in the parking sensors 17 (for example in the US Pat

Bumper arranged) or generally between secondary coil 14 and

Vehicle exterior line 15 installed. The inductive charging system 11 is preferably constructed as Einspulensystem - means that in each case a larger coil than primary coil 23 is provided and a larger coil than secondary coil 14 is present. But it is also alternatively as a primary coil 23 and secondary coil 14, a so-called multi-coil system 20 conceivable that contains a plurality of coils 21 and has. These coils 21 of the multi-coil system 20 can be selectively additionally switched on or off before or during the inductive charging process.

In the range of very high field strengths that occur in the direct air gap or gap 24 between the primary 23 and secondary coil 14, the

magnetic alternating fields in metallic objects induce electrical eddy currents and thereby inadmissibly heat them. This heating is a danger not only for personal safety, but also for the operational safety of the vehicle. Necessary component of the inductive charging system 11 is to detect metallic objects located in the air gap 24 and then bring the energy transfer in a safe state by the Power is reduced or the transmission is completely switched off. In addition to the direct danger from heated metallic objects, must protect the

Compliance with the applicable electromagnetic field limits (e.g., ICNIRP).

During the inductive energy transmission, the local magnetic field is measured by means of the at least one magnetic field sensor 12. Here are the

Magnetic field sensors 12 preferably on the outline of the vehicle 10th

arranged to best possible the stray magnetic fields on the outline of

Vehicle 10 to detect. When installing the magnetic field sensors between the secondary coil and the vehicle outer line, the magnetic field strength at the vehicle outer line is computationally determined from the locally measured value; be implemented by stored maps. Will the for the

Exceeded outside range of the vehicle predetermined limit, the charging power of the inductive charging device 11 is throttled.

When exceeding the permissible limit value GW In further

Procedural steps that can be performed in any order, further actions performed. In method step (B), the vehicle 10 is repositioned. Is the vehicle 10 not optimally with its secondary coil 14 above the primary coil 23, unwanted stray fields may form. These can be reduced by the repositioning of the vehicle 10. In a further method step (C), at least one active element 18 for controlling the magnetic field is actuated. As active elements, for example, single coils or multi-coil systems come into question, which are added to or provide a further contribution to the existing magnetic field. Furthermore, ferrites are conceivable, which can also contribute as active elements 18 to the control of the magnetic field and to the elimination of interference fields by being introduced into the charging device 11.

Alternatively, the inductive energy transmission system 11 may be designed as a multi-coil system 20. By turning on or off individual coils or at least one coil in step (D), the magnetic field can also be modified so that the resulting stray field is optimally reduced. If the limit value in method step (A) is exceeded, the driver is informed of this limit value violation in a method step (E).

On the one hand, therefore, he knows about a potential hazard and on the other he can take further steps to remedy such. Repositioning the vehicle, etc. make. It may also be information to the environment e.g. be given in the form of an activated warning light, that there is a certain risk. Finally, in a method step (F), a

Outdoor monitoring 22 activated. If this external monitor 22 is activated, it is quite possible to continue charging despite high stray fields when

it is guaranteed that no living beings in the area

of the vehicle or in the field of stray fields are present. The limit value of the magnetic field can have a value deviating from the nominal operation at the outer line of the vehicle when the approach of a living being is detected, or can take place within the method when the distance of the vehicle is detected

Living being again set to the nominal value.

Fig. 2 shows in schematic form a plan view of the motor vehicle of Fig. 1 from above. The same elements with respect to Fig. 1 are provided with the same reference numerals and are not explained in detail. Fig. 3 shows in schematic form a representation of the method according to the invention for controlling the system for inductive energy transmission. In the first method step (A), the charging power of the system for inductive energy transmission 11 is reduced or throttled, if that with the

Magnetic field sensor 12 measured magnetic field 19 exceeds a predetermined limit. After the end of the process step (A), the

Process steps (B) to (F) carried out, wherein they can be carried out individually, in parallel or in any order.

Claims

claims

1. Method for operating a system for inductive energy transmission

(11) for a vehicle (10), wherein the vehicle (10) has at least one secondary coil (14), wherein at least one magnetic field sensor

(12) for measuring a magnetic field (19) of the inductive charging device (11) on a vehicle outer line (15) or between the

Vehicle outer line (15) and the secondary coil (14) is arranged, characterized in that

- In a first process step (A), the charging power of the inductive energy transfer system (11) is throttled when measured with the magnetic field sensor (12) magnetic field (19) of the inductive energy transfer system (11) exceeds a predetermined limit.

2. The method according to claim 1, characterized in that the at least one magnetic field sensor (12) in an exterior mirror (16) of the vehicle (10) is installed.

3. The method according to claim 1, characterized in that the at least one magnetic field sensor (12) in a parking sensor (17) of the vehicle (10) is installed.

4. The method according to claim 1, characterized in that the at least one magnetic field sensor (12) in the interior (18) of the vehicle (10) is installed.

5. The method according to any one of the preceding claims, characterized

characterized in that the vehicle (10) in another

Process step (B) is repositioned.

6. The method according to any one of the preceding claims, characterized

in that at least one active element (18) for controlling the magnetic field (19) is actuated in a further method step (C).

7. The method according to any one of the preceding claims, characterized

characterized in that the inductive charging system (11) as a

Multi-coil system (20) is executed, wherein at least one coil (21) in a further process step (D) additionally turned on or turned off.

8. The method according to any one of the preceding claims, characterized

in that the driver of the vehicle (10) is informed in a further method step (E).

9. The method according to any one of the preceding claims, characterized

characterized in that an external monitoring (22) of the vehicle (10) in a further method step (F) is activated.

10. The method according to any one of the preceding claims, characterized

in that the method steps (B) to (F) are carried out in any order.

11. The method according to any one of the preceding claims, characterized

in that a limit value (GW) of the magnetic field (19) for a relevant region is predetermined by the user.

12. The method according to any one of the preceding claims, characterized

in that a limit value (GWP) dependent on the parking situation for the magnetic field (19) is transmitted to the vehicle.

13. The method according to any one of the preceding claims, characterized

characterized in that during the simultaneous operation of a plurality of systems for inductive energy transmission (11) and the possible superposition of magnetic fields (19), via a communication interface an exchange between a primary side (26) and / or a secondary side (27), based thereon one or more systems for inductive

Energy transmission (11) correspondingly reduce a transmission power.