Patent Application
20170085136
The invention relates to a monitoring apparatus for at least one electrical apparatus designed for inductive energy transmission. The invention likewise relates to an electrical apparatus designed for inductive energy transmission to a further electrical apparatus. In addition, the invention relates to a method for monitoring at least one partial surrounding area of at least one electrical apparatus designed for inductive energy transmission and to a method for inductive energy transmission between two electrical apparatuses.
An apparatus for inductive transmission of electrical energy is described in the German patent publication DE 20 2009 009 693 U1. The apparatus for transmission of electrical energy comprises a charging station having a primary coil. An induction current in a secondary coil of charging electronics for charging a battery of a vehicle is thereby to be generated by passing a current through the primary coil. A plurality of measuring coils is disposed in a housing of the primary coil, said measuring coils being connected in each case to an impedance measuring apparatus. The impedance measuring apparatuses are connected to a central evaluation device. If an energy transmission does not occur between the primary coil and the secondary coil, a measuring current of predetermined strength is applied to the measuring coils. An undesired metallic foreign body in the vicinity of the charging station can be detected based on the different impedance changes of the measuring coils.
The present invention creates options for monitoring at least one partial surrounding area of an electrical apparatus designed for inductive energy transmission, which options can still reliably carry out the desired functions thereof even when magnetic fields (generated for energy transmission) are present in the at least one coil of the coil arrangement. At the same time, a detection of foreign objects having a high sensitivity and a comparatively low error rate (of approximately zero) is ensured in all of the options for monitoring the electrical apparatus designed for inductive energy transmission that are implemented by means of the present invention. The present invention therefore contributes advantageously to safeguarding inductive energy transmissions between two electrical apparatuses.
The present invention also particularly facilitates a detection of foreign objects during an inductive energy transmission carried out without interruption. For example, it is therefore possible to charge a battery via the inductive energy transmission without a significant loss of efficiency. Because the conventional problem of the detection of foreign objects being affected by the alternating magnetic fields generated for the inductive energy transmission is eliminated, an interruption of the inductive energy transmission in order to examine at least the energy transmission path for a possibly present foreign object is prevented. In addition, a desired inductive energy transmission can be started immediately by means of the present invention without the energy transmission path to first be scanned for a possibly present foreign object. Instead, the monitoring of the energy transmission path can also be begun simultaneously with starting the inductive energy transmission.
The subject matters of the present invention particularly make it possible to determine an undesired presence of at least one foreign object which is at least in part formed from a conductive material. Thus, foreign objects consisting of critical materials, which can be quickly heated up or damaged during an inductive energy transmission, can specifically be detected in the proximity of the at least one electrical apparatus for inductive energy transmission.
The subject matters of the present invention can also be modified for an autonomous calibration. When, in fact, only one electrical apparatus is present at the desired location of the inductive energy transmission, the foreign object detection can furthermore be carried out between the electrical apparatus and a further electrical apparatus. It is therefore not necessary to dispose the two electrical apparatuses in close proximity to one another before the detection of foreign objects can be started.
The detection of foreign objects that can be carried out by means of the present invention is also very robust. Not only is an influence of external magnetic interference fields noncritical, but also ambient conditions, such as, for example, the weather, a falling of leaves, a snowfall and/or pollutants, can neither impair the sensitivity nor the low error rate of the foreign object detection.
In one advantageous embodiment of the monitoring apparatus, the at least one electronic circuit comprises at least one resonant circuit which can be set into resonance and in which the at least one coil of the coil arrangement is integrated. For example, the at least one physical variable can be determined with respect to a temporal change of at least one resonance frequency of the at least one resonant circuit, a temporal change of the at least one resonance amplitude of the at least one resonant circuit and/or a temporal change of at least one temporally averaged amplitude of the at least one resonant circuit by means of the evaluation device. At least one derivative of the at least one resonance frequency, the at least one resonance amplitude and/or the at least one temporally averaged amplitude can particularly be determined as the at least one current actual variable.
The values described here can be easily determined and can be evaluated with respect to a possible deviation from the at least one predefined normal range of values by means of cost effective electronics that require little installation space. The monitoring apparatus is thus simple to manufacture, cost effective and can be easily disposed or integrated in a desired position.
In a further advantageous embodiment, the at least one coil of the coil arrangement is integrated into at least one CCFL inverter circuit as the at least one resonant circuit. The advantages of such a circuit, which is also frequently referred to as a Royer converter or as a Royer circuit, can thus also be used for the monitoring apparatus according to the invention.
In another advantageous embodiment, the monitoring apparatus comprises at least one receiver coil as the at least one coil integrated into the at least one electronic circuit and additionally at least one transmitter coil, wherein the at least one transmitter coil can be operated by the sensor apparatus such that at least one electromagnetic signal can be transmitted by means of the at least one transmitter coil, and, during the transmission of the at least one electromagnetic signal, a voltage induced in the at least one receiver coil and/or an amperage generated in the at least one receiver coil can be ascertained by means of the at least one electronic circuit as the at least one physical variable.
The at least one receiver coil can particularly be disposed in a partially overlapping manner with respect to the at least one transmitter coil such that, when the surrounding area of the at least one receiver coil and the at least one transmitter coil is free of foreign objects, the voltage and/or amperage induced in the at least one receiver coil during the transmission of the at least one electromagnetic signal disappears.
For example, when the electrical apparatus and/or the further electrical apparatus are located in the foreign object protection mode, an inductive energy transmission between the electrical apparatus and the further electrical apparatus cannot be started, is prevented from starting at least for the predefined period of time, is concluded or can be carried out for the predefined period of time only with a reduced energy transmission rate with respect to a normal mode of the electrical apparatus and/or the further electrical apparatus. In this way, the at least one foreign object is neither undesirably heated up nor is damage to the same to be feared. In addition to the foreign object protection described here, an improved protection of the monitoring apparatus and the electrical apparatuses from damage by the heated foreign object and an improved protection of individuals in the vicinity are ensured.
In a cost effective embodiment, the coil arrangement can comprise a plurality of coils having different winding directions. As an alternative or in addition thereto, the coil arrangement can also comprise at least one bifilar coil, at least one figure-of-eight shaped coil, at least one butterfly coil and/or at least one binocular coil. It should however be noted that the listed advantageous design options for the coil arrangement are only to be interpreted in an exemplary fashion.
The coil arrangement can furthermore comprise at least one coil which has outer windings in a first winding direction and inner windings in a second winding direction that is oriented oppositely to the first winding direction. This too ensures the advantages described above.
The advantages specified above are also ensured in an electrical apparatus which is designed for inductive energy transmission to a further electrical apparatus and comprises a corresponding monitoring apparatus.
The electrical apparatus can be a charging station, a mobile device, an electric bicycle, an electric or hybrid vehicle, a three wheeler, a pedelec, a wheel chair, a mobile telephone, a portable computer and/or battery charging electronics. The present invention also thus facilitates a charging of batteries for a multiplicity of application options.
The method for monitoring at least a partial surrounding area of at least one electrical apparatus designed for inductive energy transmission also implements the corresponding advantages. The method can be modified according to the design options for the monitoring apparatus that are described above.
In addition, the advantages described can also be implemented by carrying out the corresponding method for inductive energy transmission between two electrical apparatuses.
Further features and advantages of the present invention are explained below with the aid of the drawings. In the drawings:
The monitoring apparatus 10 schematically depicted in
In order to monitor at least the partial surrounding area of the electrical apparatus, the monitoring apparatus 10 comprises a sensor device 12 with a coil arrangement comprising at least one coil 14, wherein the coil arrangement comprising the at least one coil 14 can be disposed or is disposed at, on and/or in the electrical apparatus. The coil arrangement comprising the at least coil 14 can, for example, also be integrated into the electrical apparatus. It should be noted that the monitoring apparatus 10 can however also be designed as a discrete component, which only if need be is disposed at and/or on the electrical apparatus. The at least one coil 14 of the coil arrangement can, e.g., be disposed in a coil housing 16, which can be or is disposed on a surface of the electrical apparatus. In the embodiment of
Thus, the (external) temporally variable magnetic field B cannot exert any negative influences on the measurements for detecting at least one foreign object, said measurements being carried out by means of the coils 14. This advantage is also ensured in the case of a temporally variable magnetic field B generated for an inductive energy transmission. The advantageous coil geometry of the coil arrangement comprising the at least one coil 14 allows for the use of the at least one resonant circuit 18 for detecting at least one foreign object even when a comparatively strong temporally variable magnetic field B is present. It is therefore not necessary to interrupt an inductive energy transmission, which is carried out between the electrical apparatus and the further electrical apparatus, for examining at least the partial surrounding area for a foreign object possibly present therein. The conventional necessity for interrupting the inductive energy transmission in order to carry out a monitoring for a foreign object is therefore eliminated. A use of the monitoring apparatus 10 thus facilitates a quicker execution of the inductive energy transmission. As is furthermore explained below, the foreign object monitoring can nevertheless still be reliably carried out and with a low error rate during use of the monitoring apparatus 10.
It should furthermore be noted that the implementation of the coil arrangement comprising a plurality of coils 14 having different winding directions, which is depicted in
The monitoring apparatus 10 also comprises an evaluation device 20. The evaluation device is designed to detect whether at least one physical variable Δf1 to Δfn, which is measured by means of the at least one electronic circuit 18 or appears in the at least one electronic circuit 18, differs from at least one predefined normal range of values. In the embodiment described here, the evaluation device 20 is designed to also determine the at least one physical variable Δf1 to Δfn of the at least one resonant circuit 18. This is schematically depicted in
In the embodiment of
The implementation of the evaluation device 20, which is schematically depicted in
The evaluation device 20 is, e.g., designed to ascertain whether the at least one determined physical variable Δf1 to Δfn differs from the at least one predefined normal range of values by the at least one physical variable Δf1 to Δfn being compared to at least one predetermined threshold value. If the at least one predefined threshold value has been exceeded by the at least one physical variable Δf1 to Δfn, this is generally a reliable indication of the presence of at least one foreign object in a spatial surrounding area of the at least one coil 14 of the coil arrangement. This effect is also frequently assured provided that another physical variable Δf1 to Δfn is evaluated by the evaluation device 20 instead of a gradient analysis of the at least one frequency f1 to fn of the at least one resonant circuit 18.
In the event of a (at least partially metallic and/or conductive) foreign object being present in the proximity of the at least one coil 14, eddy currents are induced in the at least one foreign object, which impair the oscillatory behavior of the at least one resonant circuit 18 that was set into resonance. Thus, the presence of the at least one undesirable foreign object can be detected by means of a comparison of the at least one physical variable Δf1 to Δfn which can be simply carried out. In so doing, a triggering of the metallic parts of the vehicle chassis is not of concern.
In the embodiment of
As an alternative or in addition to the output of the foreign object information signal 32, the evaluation device 20 can also be designed to output at least one control signal 36 to the electrical apparatus and/or further electrical apparatus designed for inductive energy transmission (to the electrical apparatus). In this case, the electrical apparatus and/or the further electrical apparatus can be directed by means of the at least one control signal 36 into a predefined foreign object protection mode at least for a predefined period of time. When the electrical apparatus and/or the further electrical apparatus are located in the predefined foreign object protection mode, an inductive energy transmission between the electrical apparatus and the further electrical apparatus preferably cannot be started, is at least prevented for a predefined period of time, is concluded or can be carried out at least for the predefined period of time only at a reduced energy transmission rate with respect to a normal mode of the electrical apparatus and/or the further electrical apparatus. After detecting a presence of the at least one foreign object, the monitoring apparatus 10 thus prevents said foreign object from overheating or being damaged as a result of a further continued inductive energy transmission at a normal energy transmission rate (corresponding to the normal mode). The monitoring apparatus 10 therefore contributes to the improved safety of objects and persons in the surrounding area of an inductive energy transmission.
The respective resonant circuit 18 can, for example, be excited via the resistor 44 with the input voltage UFG at an amplitude of 10 volts in the resonance frequency thereof, so that a sufficiently large signal-to-noise ratio is ensured. (A superelevation of the voltage UC with respect to the input voltage UFG occurs in the resonance frequency.) At the same time, the voltage profile at the capacitor 46 can be continuously recorded and evaluated.
An array can also be generated from a plurality of resonant circuits 18, said array covering a space to be monitored on at least one side. In an array, offsets, which uniformly occur across all of the coils 14 (for example due to temperature fluctuations or very low lying vehicle chassis) can be easily detected and therefore eliminated. A changing vehicle clearance leads to a systematic offset which is detected and eliminated by comparing the values of all of the array elements.
A weak coupling between adjacent coils 14 can be prevented by means of a larger distance between the coils 14. In addition, different frequencies can be applied in the case of resonant circuits 18 adjacent to coils 14 in order to further minimize a coupling.
As can be seen in
In the example of
The respective physical variable ΔA1 to ΔAn can subsequently be compared to the at least one predefined threshold value using at least one comparison unit 56. The comparison units 56 can be designed to communicate with one another by means of a communication signal 58 for adjusting the respective threshold value. Comparison signals 60 can subsequently be outputted by means of the comparison units 56, which comparison signals can subsequently be read by a central evaluation unit 62 as to whether a current variable ΔA1 to ΔAn still lies in the at least one predefined normal range of values. Provided this is not the case, at least one of the signals 32 and 36 already described can be outputted by the central evaluation unit 54.
Of the third embodiment of the monitoring apparatus 10, only a circuit diagram of the at least one resonant circuit 18 is depicted in
The CCFL inverter circuit depicted schematically in
The monitoring apparatus 10 partially schematically depicted in
In the embodiment of
The at least one receiver coil 14a of the coil arrangement, said receiver coil being depicted in
In
The electronic circuit 18 schematically depicted in
As can be seen with the aid of
The embodiment of
The embodiment of
In the embodiment of
The embodiment of
The embodiment of
All of the monitoring apparatuses 10 described above can be used in an air gap of inductive charging systems. Even in the case of an inductive transmission of comparatively large energies by means of relatively strong electromagnetic alternating fields, the monitoring apparatuses 10 can still carry out the detection of foreign objects without interrupting the inductive energy transmission (at least for a short period of time) in order to accomplish this end. At the same time, it is ensured by means of the advantageous controllability of the inductive charging systems by the monitoring apparatuses after the detection of at least one foreign object that the eddy currents induced by the alternating fields do not lead to the at least one foreign object being heated up. Instead, the inductive charging system can be actuated in a timely fashion such that undesired heating of or damage to the at least one foreign object by the conductive materials is reliably prevented. A fire or combustions due to a foreign object becoming too hot is thus reliably prevented.
In the case of all of the monitoring apparatuses 10 described above, the influence of magnetic interference fields is not critical. The monitoring apparatuses 10 can furthermore reliably carry out the detection of foreign objects without changes to a width of an interstitial gap, for example due to a changing vehicle height or an offset of the coils 14 and 14a, distorting the measurement result. In addition, all of the monitoring apparatuses 10 ensure a sufficient robustness so that ambient conditions do not contribute to a distortion of the measurement results. A one-time calibration (due to permanently present metal in at least one coil used to inductively transmit energy) is at most necessary prior to a use of the monitoring apparatuses 10.
In a modification to the monitoring apparatuses 10, said apparatuses can additionally be equipped with at least one temperature sensor. A temperature determined by means of the at least one temperature sensor can, for example, be used for selecting the at least one threshold value or for carrying out a comparison (using a characteristic diagram of values deposited for the at least one physical variable).
The advantages of the monitoring apparatuses 10 described above are also ensured for an electrical apparatus which is equipped with the same and which is designed for inductive energy transmission to a further electrical apparatus.
The method subsequently described can, for example, be carried out by means of one of the monitoring apparatuses described above. It should however be noted that the feasibility of the method is not limited to the use of such a monitoring apparatus.
In a step S1 of the method, at least one physical variable, which is measured using at least one electronic circuit or appears in the at least one electronic circuit, is determined, wherein at least one coil of a coil arrangement is connected to the respective at least one electronic circuit. The determination of the at least one physical variable takes place while the coil arrangement comprising the at least one coil is disposed at, on and/or in the electrical apparatus. It should be pointed out that the at least one coil of the coil arrangement is wound/designed and/or attached to at least one filter in such a manner that currents and/or voltages induced in the at least one coil of the coil arrangement can be at least partially averaged and or filtered out.
In step S1 of the method, at least one resonant circuit of the at least one electronic circuit, in which the at least one coil is integrated, is, for example, set into resonance while the at least one physical variable is determined. In this case, the step S1 of the method preferably comprises the sub-steps S11 and S12. In the sub-step S11, at least one frequency of the at least one resonant circuit can, e.g., be determined. In the sub-step S12, a temporal derivative of the at least one determined frequency can subsequently be formed as the at least one physical variable.
In a further advantageous embodiment, at least one electromagnetic signal is transmitted by means of at least one further coil designed as a transmitter coil while the at least one physical variable is being determined. In this case, a voltage or amperage induced in the at least one attached coil (designed as a receiver coil) is measured using the at least one electronic circuit. The at least one receiver coil can be designed in such a manner that a magnetic field homogenously permeating the at least one receiver coil induces (virtually) no voltage and/or (virtually) no current in the at least one receiver coil. The at least one receiver coil can also be alternatively integrated into the at least one electronic circuit such that induced voltages/currents are filtered out. In order to carry out the step Si of the method, means for the synchronous demodulation of the voltages/currents (comprising the alternating currents that actuate the at least one transmitter coil) that are detected in the at least one receiver coil are used in this case. The at least one demodulated signal obtained in this way can be evaluated with respect to the amplitude thereof as well as with respect to the phase thereof (relative to the respective alternating current). (The presence of a foreign object can be inferred from the amplitude of the at least one signal. The phase can be evaluated with respect to certain properties of the foreign object, such as, for example, the conductivity thereof and/or the magnetic permeability thereof—ferromagnetic or paramagnetic. The embodiment described here thus also implements a high level of sensitivity of an inductive metal detection device.)
In a step S2 of the method, it is determined whether the at least one physical variable differs from at least one predefined normal range of values. This can take place, for example, by means of a threshold value comparison. Provided the at least one determined physical variable differs from the at least one predefined normal range of values, a step S3 of the method is carried out.
In step S3 of the method, the electrical apparatus and/or a further electrical apparatus designed for the inductive energy transmission (to the former electrical apparatus) are/is controlled in a predefined foreign object control mode at least for a predefined period of time and/or at least one information output electronics for outputting at least one foreign object warning signal is actuated. Reference is made to the embodiments mentioned above regarding the foreign object protection mode and the at least one controllable information output electronics. Hence, the method schematically depicted in
The at least one ascertained physical variable can also optionally be stored in step S3 of the method. In this case, the at least one stored physical variable can be used as a comparative value when resuming the detection of foreign objects after at least one foreign object has been removed.
The method carried out above can also be carried out to improve a safety standard of an inductive energy transmission between two electrical apparatuses. The examination, which can be executed using the method, of at least the partial surrounding area of at least one of the two electrical apparatuses for a foreign object present therein or in close proximity thereto can take place prior to the start of the inductive energy transmission, during the resumed inductive energy transmission and/or during a (short-term) interruption of the inductive energy transmission. It should however be noted that an interruption of the inductive energy transmission is not necessary for carrying out the method described here.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102014205598.9 | Mar 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/078423 | 12/18/2014 | WO | 00 |
