DE102017219612A1 - Method for operating a monitoring device of an inductive power transmission unit - Google Patents

Abstract

The present invention relates to a method of operating a monitoring device of an inductive power transmission unit having a transmitting coil and a receiving coil spaced from the transmitting coil, wherein the monitoring device is adapted to monitor a gap between the transmitting coil and the receiving coil and an environment outside the gap. The receiver coil and the monitoring device are arranged in or on a vehicle, wherein the monitoring device has a sensor by means of the sensor, wherein the monitoring device uses the sensor to locate an object in the gap and / or surroundings via angle, distance and radial velocity measurements using the chirp sequence method wherein in a first step (A) the charging process is switched on and the monitoring device monitors the space for penetrating objects by means of the sensor, in a second step (B) the charging process is interrupted when an intruding object detects, in a third step (C ) the monitoring system evaluates the Doppler information supplied by the object and in a fourth step (D) adjusts the Doppler information with target-doppler signatures stored in the monitoring device.

Description

The present invention relates to a method for operating a monitoring device of an inductive power transmission unit.

State of the art

Electric vehicles usually have an electrical energy storage, such as a traction battery that provides the electrical energy for propulsion. If this electrical energy store is completely or partially discharged, then the electric vehicle has to control a charging station, at which the energy store can be recharged. So far, it is customary for this purpose that the electric vehicle is connected to the charging station by means of a cable connection at such a charging station. This connection must usually be made manually by a user. It is also necessary that charging station and electric vehicle have a mutually corresponding connection system.

Furthermore, occasionally wireless charging systems for electric vehicles are known. For this purpose, an electric vehicle is placed over a coil. This coil emits a magnetic alternating field. The alternating magnetic field is absorbed by a receiving coil within the vehicle and converted into electrical energy. By means of this electrical energy, a traction battery of the vehicle can then be charged. The publication DE 10 2011 010 049 A1 discloses such a system for charging a vehicle battery, in which the energy is transmitted inductively.

Furthermore, the energy storage of the electric vehicle can also be used for feeding back. For this purpose, a cable connection or an inductive power transmission can also be used.

In the wireless charging of a battery of an electric vehicle is located between the transmitting coil of the charging station and the receiving coil in the vehicle, a gap or air gap.

Due to the required ground clearance of motor vehicles, this air gap is a few centimeters. Air gaps in the size of 15-25 cm are very common, unless an ideal small air gap is achieved by measures such as lowering the vehicle-fixed coil, the entire vehicle or lifting the stationary coil or a combination of these measures. Due to the strong magnetic fields, which occur with relatively high magnetic flux densities, it must be ensured that living beings are not endangered by the use of the system and foreign bodies such as metallic objects are not or not heated too much. For the charging system critical foreign objects are to be detected for safe operation.
A system for wireless energy transmission is used for example in the DE 10 2009 033 236 A1 described. The monitoring of the gap in contactless charging takes place here by means of ultrasonic, radar or infrared or electronic image sensors. A disadvantage of the in the DE 10 2009 033 236 A1 is that it is not allowed to penetrate both materials, to be installed concealed, to ensure a high distance resolution and thus high separation abilities of objects, to detect living things, to detect movements and thereby to ensure a lower radiation.

There is therefore a need for a method for monitoring inductive energy transmission units that reliably detect an object, a living being or even movements in the transmission range of the inductive energy transmission path.

Disclosure of the invention

The inventive method with the characterizing part of claim 1 has the advantages of being able to detect both an object, as well as a living being and movements in the transmission range of the inductive energy transmission path.

According to the invention, a method is provided for operating a monitoring device of an inductive power transmission unit having a transmitting coil and a receiving coil spaced from the transmitting coil, wherein the monitoring device is designed to monitor a gap between the transmitting coil and the receiving coil and an environment outside the intermediate space. Advantageously, the monitoring device, since it is only connected to the vehicle, in other cases, such as parking operations, are used to monitor the area under the vehicle, for example, to protect animals or to protect the vehicle from damage when driving over dangerous objects , The receiver coil and the monitoring device are arranged in or on a vehicle, wherein the monitoring device has a sensor by means of the sensor, wherein the monitoring device uses the sensor to locate an object in the gap and / or surroundings via angle, distance and radial velocity measurements using the chirp sequence method , in a first step ( A ) the charging process is switched on and the monitoring device monitors the gap for penetrating objects by means of the sensor, in a second Step ( B ) the charging process is interrupted when a penetrating object detects, in a third step ( C ) the monitoring system evaluates the Doppler information supplied by the object and in a fourth step ( D ) Aligns the Doppler information with stored in the monitoring device Doppler signatures.

An advantage of the method is that only a single sensor (there are quite a number of sensors used) is used, for example, behind the plastic panel of the front or rear bumper or the subfloor is attached. The monitoring device also has the advantage that the entire danger zone - here the space between the transmitting and receiving coil and the surrounding danger zone surrounding the transmitting and receiving coils: the environment - can be illuminated and monitored. The method thus advantageously makes it possible to monitor the air gap of an inductive energy transmission path before and during the energy transmission by means of the monitoring device and thus to ensure that during the energy transmission there are no foreign bodies or organisms in this air gap or penetrate. The use of the chirp sequence method (the repeated sequence of FMCW ramps) allows the evaluation of distance and speed information of a detected object. On the one hand, the detection area under the vehicle can be spatially limited, which provides a robust evaluation, since foreign objects outside the vehicle can be reliably hidden. Since movements due to the high carrier frequency of the automotive radar sensor also generate high Doppler frequencies, even small movements can be detected and evaluated. This allows a more robust evaluation.

An essential advantage of the present invention is that it ensures, during the entire energy transmission, that there are no interfering foreign objects (such as objects or organisms) in the space between the transmitting coil and the receiving coil. Invasion of foreign objects (such as objects or living things) could otherwise be a major hazard during energy transfer. Thus, for example, animals which penetrate into the space between the transmitting coil and the receiving coil suffer damage due to the strong magnetic field. In addition, there is a risk that penetrating objects, especially metal-containing objects, heat up through the strong magnetic field and may even catch fire. Such intrusion of both animals and other debris can be reliably detected by the interspace monitoring of the invention. If necessary, appropriate action can then be taken.

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

Advantageously, in the first step (A) only one selective zone in the region of the transmitting coil and the receiving coil is monitored. A monitoring of the entire gap is thus eliminated advantageously, since only a small zone in the region of the transmitting and receiving coil must be monitored as protection against the magnetic field to ensure safety, for example, for living objects.

Furthermore, it is advantageous that in the second step (B) the entire gap between the vehicle and the ground is monitored. This has the advantage that, for example, when starting the vehicle no (living) object is run over and thus comes to harm.

Advantageously, the monitoring system switches on the charging process in the fifth step (E) again if no target-doppler signature is detected. The detected object is classified as non-dangerous. This allows the safe operation of the charging process.

Furthermore, it is advantageous that the monitoring system ( 3 ) all static, detected objects ( 7.1 . 7.2 ) in a sixth step ( F ) is removed by background printing and restores the initial state.

Furthermore, it is advantageous that the sensor is a radar sensor. Just by monitoring the gap between the transmitting and receiving coil by means of a radar, the magnetic field of energy transfer is not disturbed. The magnetic field for energy transfer and the radar beams of the monitoring device do not influence each other, so that the energy transfer can take place unhindered and this is done no interference.

It is advantageous that the monitoring device for distance measurement by means of the sensor uses a modulation method, preferably Frequency Modulated Continuous Wave. Modulated continuous wave radar devices, or FMCW (Frequency Modulated Continuous Wave Radar) radar, are mainly used as distance or altimeters with a short range. The distance to an object can be measured correspondingly advantageously.

Advantageously, the monitoring device uses the Doppler effect for measuring radial speeds of the object by means of the sensor. The Doppler effect is the temporal compression or elongation of a signal with changes in the distance between transmitter and receiver during the duration of the signal, which is preferred for determining the speed of an object, which enters the space between the transmitting and receiving coil or in the environment suitable.

Furthermore, it is advantageous that the monitoring device for angle measurement by means of the sensor uses the phased array technique and / or the monopulse method. The use of, for example, electronically tiltable phased array antennas, allows the fast and accurate tracking of a moving object.

Advantageously, the sensor has several transmit and receive channels. These allow the measurement or estimation of the angle of the object to be detected. Angular and distance information together provide a unique position of the object.
Advantageously, the monitoring device preferably operates the sensor at 79 GHz. The advantage of using a radar sensor in the 79 GHZ band is that the licensing for the application already exists (standard frequency for automotive applications) and the sensor has a correspondingly small size. Alternatively, the sensor is operated at 120 GHz, for example.
The monitoring device is advantageously designed to detect the penetration of an object into the space between the transmitting coil and the receiving coil and to deactivate the transmitting coil if an intrusion of an object has been detected. In this way, the inductive energy transfer can be stopped quickly. Thus, a penetrating object is not exposed to the magnetic field of the transmitting coil.

Other features and advantages of the present invention will become apparent to those skilled in the art from the following description of exemplary embodiments, which are not to be construed as limiting the invention with reference to the accompanying drawings.

list of figures

• 1: eine schematische Darstellung des Verfahrens;
• 2: eine weitere schematische Darstellung des Verfahrens;
• 3: eine weitere schematische Darstellung des Verfahrens;
• 4: eine schematische Darstellung eines Querschnitts durch ein Fahrzeug mit einer Überwachungsvorrichtung einer induktiven Energieübertragungseinheit gemäß einer Ausführungsform der Erfindung.

It shows:

• 1 : a schematic representation of the method;
• 2 : a further schematic representation of the method;
• 3 : a further schematic representation of the method;
• 4 : A schematic representation of a cross section through a vehicle with a monitoring device of an inductive power transmission unit according to an embodiment of the invention.

1 shows a schematic representation of the method according to the invention or the components according to an embodiment of the invention. The monitoring device 3 is part of an inductive energy transfer unit 8th with a transmitting coil 1 and one of the transmitting coil 1 spaced receiving coil 2 , The monitoring device 3 is designed to have a gap 30 between the transmitter coil 1 and the receiving coil 2 and an environment 31 , outside the gap 30 to monitor. The receiver coil 2 and the monitoring device 3 are in or on a vehicle 20 arranged, wherein the monitoring device 3 a sensor 6 wherein the monitoring device 3 by means of the sensor 6 an object 7 in the space 30 and / or in the environment 31 localized via angular, distance and radial velocity measurements using the Chirp Sequence method. In a first step A the charging process is switched on and the monitoring device 3 monitored by means of the sensor 6 the gap 30 for invading objects. In a second step B the charging process is interrupted when an intruding object 7 detected. In a third step C evaluates the monitoring system 3 the of the object 7 delivered Doppler information from and in a fourth step D The Doppler information is included in the monitoring device 3 stored target duplicate signatures matched.

2 shows a further schematic representation of the method according to the invention or the components according to a further embodiment of the invention. Same elements in terms of 1 are provided with the same reference numerals and are not explained in detail. The monitoring system 3 switches the charging process on again in the fifth step E if no target-doppler signature is detected. In this case, the detected object 7 classified as non-dangerous.

3 shows a further schematic representation of the method according to the invention or the components according to a further embodiment of the invention. Same elements in terms of 1 and 2 are provided with the same reference numerals and are not explained in detail. The monitoring system 3 removes the signature of the detected object 7 in a sixth step F by background subtraction and restores the initial state by all statistical objects 7.1 . 7.2 , ... are hidden.

4 shows a vehicle 20 , that over an inductive charging station or inductive energy transfer unit 8th is turned off. Same elements in terms of 1 . 2 or 3 are provided with the same reference numerals and are not explained in detail. The vehicle 20 is turned off so that the receiver coil 2 of the vehicle 20 above the transmitting coil 1 is arranged. Due to the required ground clearance of the vehicle 20 exists between the terrain 10 in which the transmitting coil 1 is arranged and the bottom or vehicle underbody / underbody 5 of the vehicle 20 in which the receiver coil 2 is located, a gap 30 with an air gap. This gap 30 with the air gap can be several centimeters. In typical vehicle types today, air gaps between 15 and 25 cm are to be expected. But other sizes for the space between terrain 10 and vehicle base are also possible. This gap 30 is usually freely accessible. Therefore, there is a possibility that in this space 30 any living thing or object can penetrate at any time. For example, animals such as dogs, cats or mice can invade. Further, there is also the danger that due to external influences objects, such as dirt (metal chips, etc.), rubbish, leaves or the like, in this space 30 can penetrate. In particular, flammable, metal-containing objects pose a great danger during the inductive charging process, since these objects heat up strongly and can then ignite if necessary. After the vehicle 20 so turned off that the receiving coil 2 in the vehicle 20 above the transmitter coil 1 can, charging the traction battery 22 (not shown here) start. For this purpose, the transmission coil generates 1 a magnetic alternating field. This alternating magnetic field is from the receiving coil 2 absorbed and converted into electrical energy. This electrical energy is then via a suitable circuit 21 (not shown here) for charging the traction battery 22 to disposal. For a return of electrical energy from the vehicle 20 conversely, in a power supply network, the coil in the vehicle can serve as a transmitting coil, which generates a magnetic field. The coil in the charging station then works as a receiving coil, which receives the energy of the magnetic field and converts it into electrical energy. This electrical energy can then be fed into a power grid.
To before or during the inductive energy transfer from the transmitter coil 1 to the receiving coil 2 make sure that in the gap 30 will not find any unwanted objects, this space becomes 30 from a monitoring device 3 supervised. The monitoring device comprises a sensor which is designed as a radar. The monitoring device uses angle measurement by means of the sensor 6 a modulation method that is preferably Frequency Modulated Continuous Wave (FMCW). The use of the chirp sequence method (repeated sequence of FMCW ramps) enables the evaluation of distance and speed information of a detected object. On the one hand, the detection area under the vehicle can be spatially limited, which provides a robust evaluation, since foreign objects outside the vehicle can be reliably hidden. Since movements due to the high carrier frequency of the automotive radar sensor also generate high Doppler frequencies, even slow movements can be detected and evaluated. This enables a robust evaluation. From these evaluation possibilities, the detection scheme described below can be derived:

If the charging process is switched on, the sensor monitors 6 the gap 30 for invading objects 7 by the objects 7 be located two-dimensionally. This methodology allows a dynamic adaptation of the detection range depending on charging power or coupling factor. As long as no object 7 enters the monitoring area, the charging process remains switched on.

Became a penetrating object 7 detected, the energy transfer unit 8th initially switched off and the sensor evaluates the Doppler information provided by the object. As long as the object is moving, the charging system will remain off because there are significant Doppler signals. The decisive factor is the evaluation of weakly moving objects such as a sleeping cat or a branch moved by the wind, the latter potentially posing no danger to the inductive charging system. Here you can set the target duplicate signatures, eg breathing or heartbeat. This allows the random movements of an unchallenged object to be distinguished from an endangered object. If, therefore, an endangered object is detected, the system remains switched off. Can not detect a signature that is a vulnerable object 7 can be assigned, the system can be turned on again.

For the detection of radial velocities of an object 7 in the space between 30 or in the environment 31 is located, the monitoring device uses the Doppler effect. In order to determine the angle information or object arrangement relative to the vehicle axis, the monitoring device uses the phased array technique or the monopulse method and advantageously has several transmit and receive channels. The radar is preferably operated in the 79 GHz frequency band, but can also be designed as ultra-wideband radar his. Preferably, a high bandwidth of at least 2 GHz is used to obtain a sufficient distance separation of the measurement method.
The emitted electromagnetic waves are reflected on objects that differ in their electrical properties from the propagation medium (eg air). The reflected signals are registered in the receiver and their transit time or phase and amplitude are determined. By measuring the transit time and phase, a distance determination is possible. In addition, electromagnetic waves in different polarization directions can be used. This information can be used to construct a polarimetric radar system which uses the polarization information (backscatter properties of objects are dependent not only on the frequency used but also on the polarization of the incident electromagnetic wave) additional object discrimination.

If charging is to begin, a transmitting coil will first be activated 1 provided. For example, it may be the transmitting coil of a charging station for the electric vehicle. Furthermore, a receiving coil 2 provided. This may be, for example, the receiving coil in the electric vehicle with which the traction battery is to be recharged. Finally, there is an inductive energy transfer from the transmitting coil 1 to the receiving coil 2 , This is followed by the space between the transmission coil 1 and the receiving coil 2 with the monitoring device 3 supervised. Will now the penetration of an object in the space 30 between transmission coil 1 and receiver coil 2 or in their environment 31 is detected, then the energy transfer between the transmitting coil 1 and receiver coil 2 interrupted.
Optionally, then signaling may occur when in the gap 30 between transmission coil 1 and receiver coil 2 an object was detected. This signaling may, for example, be the output of an optical and / or acoustic signal. In addition or as an alternative, the notification of a remote user can also be effected by means of a radio link. For this example, a mobile phone connection, a wireless connection or the like can be used.

A further embodiment variant is the combination of the application of the live object detection monitoring device with an application for automatic driving, positioning and parking operations.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• DE 102011010049 A1 [0003]
• DE 102009033236 A1 Résumé

Claims (11)

Method for operating a monitoring device (3) of an inductive energy transmission unit (8) with a transmitting coil (1) and a receiving coil (2) spaced from the transmitting coil (1), the monitoring device (3) being designed to interpose a gap (30) between the transmitting coil (1) and the receiving coil (2) and an environment (31) to monitor outside of the intermediate space (30), wherein the receiving coil (2) and the monitoring device (3) are arranged in or on a vehicle (20), wherein the monitoring device (3) has a sensor (6), wherein the monitoring device (3) by means of the sensor (6) an object (7) in the space (30) and / or in the environment (31) via angle, distance and Localized radial speed measurements using the chirp sequence method, characterized in that - in the first step (A), the charging is turned on and the monitoring device (3) by means of the sensor (6) the space (30) after one monitors ringing objects; - In the second step (B), the charging is interrupted when a penetrating object (7) detected; in a third step (C), the monitoring system (3) evaluates the Doppler information supplied by the object (7); in a fourth step (D), the Doppler information is compared with target doppler signatures stored in the monitoring device (3). Method according to Claim 1 , characterized in that in the first step (A) only a selective zone in the region of the transmitting coil (1) and the receiving coil (2) is monitored. Method according to one of the preceding claims, characterized in that in the second step (B) of the entire gap (30) between the vehicle (20) and the ground is monitored. Method according to one of the preceding claims, characterized in that the monitoring system (3) the charging process in the fifth step (E) turns on again, if no Doppler signature is detected and classifies the detected object (7) as non-dangerous. Method according to one of the preceding claims, characterized in that the monitoring system (3) removes the signature of the detected object (7) in a sixth step (F) by background subtraction and restores the initial state in which all statistical objects (7.1, 7.2, .. .) are hidden. Method according to one of the preceding claims, characterized in that the sensor (6) is a radar sensor. Method according to one of the preceding claims, characterized in that the monitoring device (3) for distance measurement by means of the sensor (6) uses a modulation method, preferably Frequency Modulated Continuous Wave. Method according to one of the preceding claims, characterized in that the monitoring device (3) for measuring radial velocities of the object (7) by means of the sensor (6) uses the Doppler effect. Method according to one of the preceding claims, characterized in that the monitoring device (3) for angle measurement by means of the sensor (6) uses the phased array technique and / or the monopulse method. Method according to one of the preceding claims, characterized in that the sensor (6) has a plurality of transmitting and receiving channels. Method according to one of the preceding claims, characterized in that the monitoring device (3) preferably operates the sensor (6) at 79 GHz.

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