DE102018211100A1 - Method and device for recognizing objects - Google Patents

Abstract

Method and device for recognizing objects in the vicinity of a charging device of electrically operated devices, where the charging device is equipped with a primary coil which is suitable and designed to generate a magnetic field for inductively applying electrical energy to a secondary coil which is a component the electrically operated device is to be transmitted. The charging arrangement has a detection device for detecting objects, which has a coil arrangement with a plurality of coils, and the detection device is set up to detect objects by changes in the capacitance value between coils.

Description

The present invention relates to a device and a method for detecting or recognizing objects or for detecting the presence of objects, in particular objects that are foreign objects. The device and method are described with reference to a system for charging electrically powered vehicles. However, it is pointed out that this device for detecting objects can also be used in other areas. The foreign bodies, which can also be referred to as foreign objects, can be both inorganic bodies such as metallic bodies and organic bodies such as animals and humans.

Electromobility has recently gained in importance and is an important topic for many motor vehicle manufacturers. However, electric vehicles need to be charged. For this purpose, several procedures are already known in the prior art, for example via plug connections and the like. Charging systems are also known, which carry out the charging process inductively and in particular without contact. For this purpose, the motor vehicle can be positioned via a charger, for example, and this charger has a primary or transmitter coil, with which a coil of the vehicle-side charging system is supplied inductively.

The charging arrangement is, in particular, a primary or transmitting module which is suitable and intended for inductively supplying energy to a secondary or receiving module (for example a module having a secondary coil) of the object to be charged (e.g. a vehicle).

With inductive charging, energy is transmitted electromagnetically between one or more primary and secondary coils. Due to the high transmission power, e.g. When charging electric vehicles or hybrid vehicles in the air gap, a strong electromagnetic field (several mT) is created. Significant safety problems with these procedures can represent foreign objects or foreign bodies that lie between the coils or on the charging station, for example. Foreign objects with a metallic component can become a security risk. Metallic or electrically conductive or ferromagnetic objects in the air gap can become very hot during charging and thus lead to damage. Therefore, such charging devices contain security systems for monitoring the magnetic field and the air gap with regard to foreign objects and foreign bodies.

There can also be a safety risk for people or animals during the charging process, for example children playing with their hands between the charging elements or a cat who wants to sleep on the lower charging element.

A suitable system for the detection of ferromagnetic, electrically conductive or objects with mixed electromagnetic properties in the air gap is a matrix of coils above the primary coil.

For example, are known DE 102015112431 A1 and WO 2014/063159 A2 , In the known solutions, the coils in the EM field and the voltages induced therein are also used, and the functionality is thus optimized by various methods.

In the known solutions, special electrical capacitor elements are also used and the capacitance of these capacitors or capacitor systems is then analyzed in order to detect various objects and their behavior.

Objects that can influence these capacitor or sensor capacities or their capacitance values can be detected by means of separately installed capacitors or special capacitive sensors.

The present invention is therefore based on the object of increasing the safety of inductive charging devices. This object is achieved according to the invention by the device and the method of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

Another object of the invention is to provide a device which enables objects to be recognized or detected, and in particular to determine the presence of objects, in a cost-effective manner.

A charging arrangement according to the invention has a primary or transmitter coil which is suitable and intended to generate a magnetic field and thereby inductively transmit electrical energy to a secondary or receiver coil, which is a component of an electrically operated device such as an electrically operated vehicle , The charging arrangement has a detection device for recognizing and detecting objects, in particular foreign objects or foreign bodies, which are located between the transmitting coil and the receiving coil. If there are one or more (foreign) objects or foreign bodies on the coils, these can increase the capacity accordingly between coils. On the basis of the capacitance behavior or differences in one or more coils, the presence of these objects is determined or these objects can be detected.

• 1 eine Vorrichtung zum Laden von elektrisch betriebenen Einrichtungen,
• 2 eine schematische Darstellung einer erfindungsgemäßen Spulenanordnung,
• 3 eine schematische Darstellung einer erfindungsgemäßen Kapazitätsanalyse für die Kapazitätsmessung, und
• 4 eine schematische Darstellung einer erfindungsgemäßen Objekterkennung.

The invention will be explained in more detail below on the basis of exemplary embodiments with the aid of figures. Show:

• 1 a device for charging electrically operated devices,
• 2 1 shows a schematic illustration of a coil arrangement according to the invention,
• 3 a schematic representation of a capacity analysis according to the invention for the capacity measurement, and
• 4 is a schematic representation of an object detection according to the invention.

1 shows a device for loading ( 101 ) of electrically operated devices ( 102 ) with a primary coil ( L1 ), which generates a magnetic field to inductively apply electrical energy to a secondary coil ( L2 ) transferred to. An example is an electrically powered vehicle ( 102 ) with battery ( BAT ) mapped. The primary coil ( L1 ) and secondary coil ( L2 ) are each in a ground assembly G1 and a vehicle assembly G2 embedded.

In the 2 For example, a large number of coils are recorded as a coil matrix or coil arrangement. Such coil arrangements can also be present in known solutions, where they are used for field condition analysis by the induced voltages. The magnetic field is called H (t) respectively. B (t) shown. The coils are numbered in the first column as 1 to 4 or U1 . U2 , etc., and in further rows until 24 , This defines a rectangular coil matrix as an example.

The coil form of the existing coils for the voltage induction method described - which can also be referred to as coil windings or coil wires - are used in this invention as capacitor plates for the capacitance measurement. Examples of the capacity analysis or capacity measurement are based on the 3 displayed.

The intrinsic capacities of the individual coils numbered in the figures can be considered as individual values in the process ( C1 . C2 , ... etc.). The capacities between some coils are designated here for the description according to the numbering as follows: the capacitance value C1-2 means the capacitance between the coils 1 and 2 , the capacity value C1_21 means the capacitance between the coils 1 and 21 etc. for other coils and their combinations.

Like in the 2 , drawn when two coordinate axes are shown here, namely the x-axis in the direction of the coils 1 . 5 . 9 . 13 . 17 . 21 and the Y axis in the direction of the coils 1 . 2 . 3 . 4 . 5 , then a coordinate system is determined in the area of the coil matrix. The capacitance measurements can be made in the directions of the two axes, such as along the X direction between coils 1 . 5 or 5 . 9 or 9 . 13 in the vicinity and between coils 1 . 9 or 5 . 13 or between coil groups 1 + 5 and 9 + 13, or between 1 + 5 + 9 and 13 + 17 + 21 etc. etc. Measurements can be made similarly for other rows, such as between groups 2 + 3 + 6 + 7 and 19+ 23 + 18 + 22nd The object presence and, for example, average object dimensions in the x direction can thus be queried.

Using an identical procedure, the capacitance values and therefore, for example, the object dimension in the Y direction with corresponding coil combinations and groups (such as between 1 . 2 or 3 . 4 , or between groups 5 + 6 + 9 + 10 and 7 + 8 + 11 + 12).

Using a similar procedure, other directions can also be included, such as between coils 1 . 11 or 5.15 or 4, 13 or 8, 17 and also between groups 1 + 2 + 5 + 6 and 19 + 20 + 23 + 24. This allows additional information about objects and their properties to be obtained.

The capacity value query in different directions as well as the comparison with references (which have to be formed in advance), without objects and / or with sample objects with known properties (dimensions, metal, dielectrics, mixed: conductive-non-conductive, magnetic-non-magnetic, etc.), form the information source for the recognition (detection) of the objects and the determination of their properties.

In one embodiment, the initial state of the coil matrix can be measured or analyzed with all relevant capacities without foreign objects, and measured values can be recorded. The initial state of the coil matrix can also be measured or analyzed without useful objects such as devices for charging or electronic modules for receiving energy, and measured values can be recorded. The measurements and the analysis can preferably be carried out in a dirt or interference-free state. The measured values can be saved as a reference. The measured values can be used for comparison and / or evaluation.

In one embodiment, deviations from the reference can serve as a source of information for the detection of object presence, such as the presence of useful objects and foreign objects. As an example, the values C1-2 . C1-3 , ..., C1_21 , and also C 2-3 . C2 4 ... as compared in the reference and as currently measured.

With the o.G. Detection or device is possible without an EM field. Visibility and accuracy can be increased significantly. Contamination can also be detected, and stationary and slowly moving objects can be detected. The method can be used for some existing coil matrix solutions without installing additional sensor parts in order to significantly improve the functionality. Ultimately, parasitic capacitances of the coils can be used as an advantageous sensor property.

Also based on the o.G. The device or method is the detection of the electrical and dielectric material properties of the objects, e.g. Snow, liquids, snowmatch with or without salt, dry and / or wet waste etc. possible without additional sensor hardware for the existing coils of the coil matrix or coil arrangement, based on changes in the capacitive properties of the coils.

Any combination of intermediate capacities from coil pairs or coil groups is possible. Coil groups consisting of two, three or more coils or turns are possible. The groups can be created by galvanic connections, which can be set and separated dynamically. Transistors such as FET (field effect transistors) could be used for the connections. Quickly switchable connections are preferred so that groups can be set up and changed quickly.

Galvanic isolation is required to determine capacitance values between coils or groups of coils. Electrical isolation can be achieved using high-resistance switches such as can be achieved by electronic switches, for example semiconductor switches such as FETs or MOSFETs. In a preferred embodiment, coils are electrically isolated on both sides or on all sides, with which there is no longer any electrical connection.

Capacitance variations that indicate an object presence can be detected between two groups of coils, or they can be detected between a group of coils and a single coil, or they can be detected between individual coils. The reference values for all groups used must of course be formed in advance.

In order to achieve even better accuracy, sensitivity and spatial resolution, coil formers or coil turns that are galvanically separated from one another are preferred. In another version, coil formers or coil turns can be galvanically separated if necessary in order to achieve even better accuracy, sensitivity and spatial resolution if required or as desired.

If the coil form or coil turns remain galvanically connected, the capacitance between coil groups or between coil groups and individual coils should be considered in the method or the device.

A possible case with two objects ( 410 . 420 ) is in the 4 shown. Here is object 410 at close range and object 420 a little further from the coils 1 - 24 shown in the coil matrix.

In the 4 is capacity, for example C12_20 due to the presence of at least the object 420 changed and is therefore from the partial capacities C12_20a and C12_20b exist or the capacity value C12_20 is due to by at least the object 420 influenced environmental properties changed. The same applies to object 410 that is close to the coils, for example. The most influenced capacities bring information about where and how large the object or an object group can be. In addition, the influenced capacities can provide information about what properties these objects can have. If the capacitance values have been compared in several directions, then the comparison values can provide further information about the properties of the objects.

As mentioned above, groups of coils or windings can be used to obtain better or more accurate information. These groups can be designed statically or switched dynamically. They can be created according to a given program, or as needed to better recognize objects. In one embodiment, capacitance values are measured in a first step, and potential objects or foreign objects are recognized in a second step. In a third step, groups of coils are formed or newly formed on the basis of identified potential objects or foreign objects. In a fourth step, capacitance values are measured again.

Designs as described above are typically supplemented by system elements not shown. Executions can be three Components, namely a signal generator, for example in the form of a sine or pulse source, an electrical network that responds to objects, and a sensor device or a detector; other configurations are also possible. The signal generator or the source serves as a signal source and preferably generates a periodic sine signal or periodic pulses. The signal generator can be designed as an oscillator, for example. The signal generator could also be designed in a broadband manner with variable frequencies, for example as a frequency synthesizer or another pulse generator.

The second element is the electrical network or the circuit as a sensor element. This has at least one electrical component or a combination of components whose capacitance is changed by approaching the object.

Thirdly, there is a detector for signal acquisition and processing of the signal. Several versions are possible. This detector can have, for example, a directional coupler, a logarithmic amplifier, a rectifier or an AD converter. Combinations thereof or the use of several of the devices mentioned have also been considered by the inventor.

It is pointed out that features were also described in the figures, which in themselves can be advantageous. The person skilled in the art recognizes that a certain feature described in a figure can be advantageous even without the adoption of further features from this figure. The person skilled in the art further recognizes that an advantage can also result from a combination of several features shown in individual or in different figures.

LIST OF REFERENCE NUMBERS

1-24

Coils or bobbin or coil turn

101

Loading device

102

electrically operated devices

410, 420

objects

B (t), H (t)

magnetic field

BAT

battery

C1-4

Capacity between the coils 1 and 4

C1-5

Capacity between the coils 1 and 5

C1_9

Capacity between the coils 1 and 9

C1_21

Capacity between the coils 1 and 21

C12 20

Capacity between the coils 12 and 20

C12_20a, C12_20b

partial capacitances

L1

primary coil

L2

secondary coil

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015112431 A1 [0007]
• WO 2014/063159 A2 [0007]

Claims (15)

Device for recognizing objects in the vicinity of a charging device (101) of electrically operated devices (102), the charging device being equipped with a primary coil (L1) which is suitable and designed to generate a magnetic field in order to generate electrical energy to be transmitted inductively to a secondary coil (L2), which is part of the electrically operated device, the charging arrangement having a detection device (G1, 201, 301, 401) for detecting objects, the detection device comprising a coil arrangement with a plurality of coils ( 1-24), characterized in that the detection device is set up to detect objects by changing the capacitance value between coils. Device after Claim 1 , characterized in that the detection device is set up to recognize objects by changes in the capacitance value between groups of coils. Device according to at least one of the preceding claims, characterized in that both groups with two or three coils and groups with more than four coils are formed in order to measure the capacitance value. Device according to at least one of the preceding claims, characterized in that the detection device is set up to dynamically form and change groups of coils. Device according to at least one of the preceding claims, characterized in that groups of coils are formed as required to measure the capacitance value. Device according to at least one of the preceding claims, characterized in that the detection device is set up to form groups of coils on the basis of knowledge from capacitance value measurements in order to measure the capacitance value. Device according to at least one of the preceding claims, characterized in that the coils are galvanically separated from one another. Device according to one of the Claims 1 - 6 , characterized in that the coils can be galvanically separated from one another. Method for detecting objects using a coil arrangement with a large number of coils (1-24), characterized in that the coils are used as capacitor plates for the capacitance measurement, and objects or foreign objects are recognized by changes in the capacitance value between coils. Procedure according to Claim 9 , characterized in that changes in the capacitance value is used to detect the electrical and dielectric material properties of the objects or foreign objects. Procedure according to one of the Claims 9 - 10 , characterized in that a reference is formed from measured values, and measurements that deviate from the reference are used for object and foreign object detection. Procedure according to one of the Claims 9 - 11 , characterized in that the reference is formed in an initial state and without foreign objects. Procedure according to one of the Claims 9 - 12 , characterized in that the reference is formed as a matrix. Procedure according to one of the Claims 9 - 13 , characterized in that the capacitance value or the capacitance values between coil pairs or coil groups are measured. Procedure according to Claim 14 , characterized in that a coil group consists of a single coil.

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