DE102016217703A1 - Method for determining information relating to an inductive coupling system - Google Patents

Abstract

The invention relates to a method (500) for determining information relating to an inductive charging system for inductively charging an electrical energy store of a vehicle (100), wherein the inductive coupling system comprises a primary coil (111) and a secondary coil (121) that magnetically interact with one another are coupled. The method (500) comprises determining (501) actual parameter values from a plurality of parameters (331) of a model (330) of the inductive coupling system. In addition, the method (500) includes determining (502) information related to the inductive coupling system based on the actual parameter values and based on mathematical functions for desired parameter values of the parameters (331). The mathematical function for a parameter (331) indicates the desired parameter values of the parameter (331) as a function of a relative position between the primary coil (111) and the secondary coil (121) of the inductive coupling system.

Description

The invention relates to a method and an evaluation unit for determining information relating to an inductive charging system for the inductive charging of the energy storage device of a vehicle.

Electric vehicles typically have a battery (i.e., an electrical energy store) in which electrical energy can be stored to operate an electric machine of the vehicle. The battery of the vehicle can be charged with electrical energy from a power grid. For this purpose, the battery is coupled to the power grid to transfer the electrical energy from the power grid into the battery of the vehicle. The coupling can be wired (via a charging cable) and / or wireless (based on an inductive coupling between a charging station and the vehicle).

One approach to automatically, wirelessly, inductively charging the battery of the vehicle is to transmit electrical energy to the battery from the floor to the underbody of the vehicle via magnetic induction via the underbody clearance. This is exemplary in 1 shown. In particular shows 1 a vehicle 100 with an energy storage 103 for electrical energy (eg with a rechargeable battery 103 ). The vehicle 100 includes a secondary coil 121 in the vehicle underbody, with the secondary coil 121 via an impedance matching (not shown) and a rectifier 101 with the memory 103 connected to electrical energy. The secondary coil 121 is typically part of a so-called "Wireless Power Transfer" (WPT) vehicle unit 120 or secondary unit 120 ,

The secondary coil 121 the WPT vehicle unit 120 can over a primary coil 111 be positioned, the primary coil 111 z. B. is mounted on the floor of a garage. The primary coil 111 is typically part of a so-called WPT ground unit 110 or primary unit 110 , The primary coil 111 is with a power supply 113 connected. The power supply 113 may include a radio-frequency generator that provides an alternating current in the primary coil of the WPT ground unit 110 is generated (which is also referred to in this document as a primary current), whereby a magnetic field (in particular a magnetic charging field) is induced. The magnetic charging field may have a frequency from a predefined charging field frequency range. The charging field frequency of the electromagnetic charging field can be in the range of 80-90 kHz (in particular at 85 kHz).

With sufficient magnetic coupling between primary coil 111 the WPT ground unit 110 and secondary coil 121 the WPT vehicle unit 120 about the underbody freedom 130 becomes by the magnetic field a corresponding voltage and thus also a current in the secondary coil 121 (also referred to as secondary current in this document). The induced current in the secondary coil 121 the WPT vehicle unit 120 is through the rectifier 101 rectified and in memory 103 saved. So, electric power can be wireless from the power supply 113 to the energy storage 103 of the vehicle 100 be transmitted. The charging process can be in the vehicle 100 through a charging control unit 105 to be controlled. The charging control unit 105 may be set up for this purpose, e.g. B. wirelessly (such as over Wi-Fi), with the WPT ground unit 110 to communicate.

To maximize field strengths of the magnetic charging field for bridging the underbody clearance 130 To be able to produce resonant systems can be used. Here are both the primary coil 111 as well as the secondary coil 121 integrated into resonant circuits, via the primary coil 111 and the secondary coil 121 coupled together. In particular, in a primary resonant circuit of the WPT ground unit 110 due to a relatively low coupling factor between primary coil 111 and secondary coil 121 typically uses relatively high primary currents to produce a magnetic charging field with sufficient field strength.

The distance between primary coil 111 and secondary coil 121 can vary quite a bit. In particular, the height of the underbody clearance 130 be different for different vehicle models (sedan vs. SUV). Furthermore, it may be due to imprecise parking of the vehicle 100 in the parking position to a lateral offset of the coils 111 . 121 come. As a consequence, different transmission parameters result (in particular different sizes of the coupling factor and different effective inductances of the primary coil 111 or the secondary coil 121 ) for the WPT ground unit inductive coupling system 110 and WPT vehicle unit 120 ,

Due to the various factors influencing the transmission parameters of an inductive charging system, it can typically not be determined in a precise manner whether an inductive charging system has a technical charging system Has a defect (eg a broken coil) and / or unfavorable positions between the WPT ground unit 110 and the WPT vehicle unit 120 is present.

The present document addresses the technical problem of efficiently and precisely determining information related to an inductive coupling system for charging a vehicle energy storage.

The object is solved by the independent claim. Advantageous embodiments are u. a. in the dependent claims.

According to one aspect, a method is described for determining information relating to an inductive coupling system for inductively charging an electrical energy store of a vehicle. The method may, for. B. be carried out by an evaluation or control unit of the vehicle. The inductive coupling system includes a primary coil (as part of a WPT ground unit) and a secondary coil (as part of a WPT vehicle unit), with the primary and secondary coils magnetically coupled together.

The method comprises determining actual parameter values of a plurality of parameters of a model of the inductive coupling system. The parameters may describe one or more inductive properties of the inductive coupling system. In particular, the model with the parameters can describe the electromagnetic behavior of the inductive coupling system (in an approximate manner). The parameters can z. B. indicate a degree of coupling between the primary coil and the secondary coil and / or inductance values of the primary coil and the secondary coil.

The inductive coupling system comprises two magnetically coupled coils that form a transformer. The model of the inductive coupling system may comprise an electrical equivalent circuit diagram or an electrical equivalent circuit of the inductive coupling system, and in particular an electrical equivalent circuit diagram or an electrical equivalent circuit of a transformer (eg a T equivalent circuit diagram). The parameters may include inductances (eg an effective inductance and / or a mutual inductance) and possibly resistances of an electrical equivalent circuit diagram of the inductive coupling system. An equivalent electrical circuit typically includes a plurality of idealized electrical components (particularly idealized coils and possibly linear resistors). The parameters may describe the characteristics of the different idealized electrical components of the equivalent electrical circuit (eg, the inductors).

The model of the inductive coupling system can describe measurable physical quantities of the inductive coupling system as a function of the parameters. In other words, the model can describe a relationship between measurable physical quantities of the inductive coupling system and the parameters (eg in the form of an electrical equivalent circuit diagram of the inductive coupling system). The measurable physical quantities may include currents and / or voltages at the primary coil and the secondary coil or currents and / or voltages at the idealized, electrical components of the equivalent circuit diagram.

By using a model of the inductive coupling system, the inductive coupling system can be described efficiently. In particular, properties of the inductive coupling system that are relevant to electromagnetic energy transmission (i.e., parameter values for the parameters of the model) can thus be efficiently determined based on (current or voltage) measurements on the real inductive coupling system.

The method further includes determining information related to the inductive coupling system based on the actual parameter values and based on mathematical functions for desired parameter values of the parameters of the model. In particular, a mathematical function can be provided for each (considered) parameter of the model. The mathematical function for a parameter indicates the desired parameter values of the parameter as a function of a relative position between the primary coil and the secondary coil of the inductive coupling system. The relative position between the primary coil and the secondary coil may, for. By Cartesian coordinates (i.e., by distances in X, Y and Z directions). The mathematical function for a parameter may then indicate the desired parameter values of the parameter as a function of x, y, and z.

The method makes it possible by using a model of the inductive coupling system with several (inductively relevant) parameters and by the use of mathematical functions for Describing the desired parameter values of the (inductive-relevant) parameters of the inductive coupling system to determine in an efficient and precise manner information relating to the inductive coupling system (eg a current relative position between the primary coil and the secondary coil).

The mathematical function for a parameter can be determined in advance by measuring the inductive coupling system. In particular, maps for the parameters of the (model of) inductive coupling system can be detected. The characteristic map for a parameter may include values of the parameter as a function of the relative position between the primary coil and the secondary coil (eg as a function of x, y, z). The mathematical function for the parameter can then be determined by approximation, in particular by means of linear regression, of the characteristic map for the parameter.

The mathematical function for a parameter may in particular comprise an analytic function, for example a polynomial of a certain order (eg 3rd, 5th, 10th or higher order). In this case, the mathematical function can be determined in such a way that the function approximates the characteristic map as well as possible (eg in the quadratic mean). Alternatively, the mathematical function z. B. include a neural network that has been learned based on measurements of the map.

The mathematical function may specify a desired parameter value of a parameter as a function of different positional variables for describing the relative position between the primary coil and the secondary coil. The position variables can indicate distances between the primary coil and the secondary coil, eg. In Cartesian coordinates or in polar coordinates. The position variables can, for. Example, a distance in the X direction, a distance in the Y direction and / or display a distance in the Z direction. Exemplary further position variables are z. B. the angle of rotation between the primary and secondary coil 111 . 121 , In particular, a mathematical function may have a desired parameter value of a parameter as a function of the angle of rotation between the primary coil 111 and the secondary coil 121 describe.

The mathematical function is preferably continuous with respect to a position variable and continuously derivable according to a position variable. Thus, the mathematical function for a model of the inductive coupling system can be efficiently used to determine information related to the current state of the inductive coupling system (eg, as part of an optimization process).

The determination of information related to the inductive coupling system may include reducing a cost function that indicates a deviation of the actual parameter values from the desired parameter values given by the mathematical functions (eg, a mean square distance). Reducing (in particular minimizing) the cost function can be done by varying the relative position between the primary coil and the secondary coil. In particular, a relative actual position between the primary coil and the secondary coil can be determined, by which the cost function is reduced, in particular minimized. Furthermore, a minimum value of the cost function can be determined.

The information relating to the inductive coupling system may thus include information relating to a relative actual position between the primary coil and the secondary coil. The method may thus be used for efficient and accurate positioning of a vehicle over a WPT ground unit.

The method may include determining a relative output position between the primary coil and the secondary coil (eg, at the beginning of a charge). The starting position can z. B. be determined by the method described in this document. Alternatively or additionally, other positioning methods (eg, camera-based positioning methods) may be used to determine the relative home position. The information relating to the inductive coupling system can then also be determined on the basis of the relative output position. So z. B. the relative actual position between the primary coil and the secondary coil can be determined with increased accuracy (in particular can be avoided by taking into account an output position possible ambiguities in the determination of the relative actual position).

Alternatively or additionally, defects or disturbances of the inductive coupling system can be detected by taking account of an output position. For example, it may be detected that the relative actual position deviates from the relative output position although the vehicle was not moved between the time of determining the relative output position and the time of determining the relative actual position. This can be an indication that a disturbing object has moved between the primary coil and the secondary coil and / or that the inductive coupling system has a defect. It can then be an inductive charging of the electrical energy storage of the vehicle via the inductive Pairing system to be canceled. Thus, the safety of inductive charging can be increased in an efficient and reliable manner.

Alternatively, z. For example, it may be determined that the relative actual position deviates from the relative home position because the underfloor clearance between the vehicle and WPT ground unit has changed. In particular, a deviation of the actual position from the starting position in the Z direction can be detected (with substantially unchanged positioning in the X / Y direction). It can then be closed on a loading or unloading of the vehicle. In this case, an adjustment of an operating point (eg, an adaptation of a frequency of the charging field) may be made to improve the energy efficiency of the inductive charging process. Thus, the energy efficiency of inductive charging can be increased in an efficient and reliable manner.

The inductive coupling system may additionally comprise (at least) one measuring coil. The parameters of the model of the inductive coupling system can then comprise (at least) one parameter which depends on a degree of coupling between the measuring coil on the one hand and the primary coil and / or the secondary coil on the other hand. By taking into account a further measuring coil symmetries of the inductive coupling system and thus ambiguities in the determination of information in relation to the inductive coupling system can be eliminated.

In accordance with a further aspect, an evaluation unit or a control unit (for example with a processor) which is set up to carry out the method described in this document is described.

According to a further aspect, a vehicle (in particular a road motor vehicle, for example a passenger car, a lorry or a motorcycle) is described, which comprises the evaluation unit or control unit described in this document.

In another aspect, a software (SW) program is described. The SW program can be set up to run on a processor and thereby perform the method described in this document.

In another aspect, a storage medium is described. The storage medium may include a SW program that is set up to run on a processor and thereby perform the method described in this document.

It should be understood that the methods, devices and systems described herein may be used alone as well as in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, devices, and systems described herein may be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

Furthermore, the invention will be described in more detail with reference to exemplary embodiments. Show

1 exemplary components of an inductive charging system;

2 exemplary components of a WPT ground unit and a WPT vehicle unit;

3a an exemplary inductive coupling system;

3b an exemplary model for an inductive coupling system;

3c exemplary parameter profiles of an inductive coupling system;

4 exemplary courses of cost functions (with only the x-coordinate shown as an example); and

5 a flowchart of an exemplary method for determining the state of an inductive coupling system.

Due to tolerances when parking a vehicle 100 over a primary coil 111 and / or due to varying underbody freedoms 130 (eg due to different loading states of the vehicle 100 In the case of an inductive charging system, relatively large mechanical tolerances result (eg -7 to +7 cm in the X-direction, -10 to +10 cm in the Y-direction, 10 to 16 cm in the Z-direction). These mechanical or local tolerances typically lead to a relatively large dispersion of the parameters of the inductive charging system (in particular the parameters L ₁ , L ₂ and k). Due to the relatively large variance of the possible parameter values of the inductive coupling system (ie of the inductive charging system), only a relatively rough diagnosis with respect to a state of the coupling system is typically possible. In particular, can not be reliably detected, if a coil 111 . 121 is broken, whether a vehicle 100 with respect to the bottom coil 111 is shifted and / or whether z. B. a foreign body obstructs the inductive energy transfer. Furthermore, the setting of an operating point for an inductive charging process is usually insufficient, since the state of the inductive charging system is only insufficiently known.

The present document therefore deals with the efficient and accurate detection of information regarding the condition of an inductive charging system for the inductive charging of a vehicle.

ergibt. Die Ladefeld-Frequenz ist bevorzugt nahe an der Resonanzfrequenz f₀, um einen möglichst hohen Primärstrom durch die Primärspule 111 zu erzeugen (durch eine Resonanz). Ein hoher Primärstrom ist typischerweise erforderlich, da der Kopplungsfaktor k 230 zwischen Primärspule 111 und Sekundärspule 121 aufgrund des großen Luftspaltes 130 relativ klein ist, z. B. k ~ 0.1. 2 shows a circuit diagram of a WPT ground unit 110 and a WPT vehicle unit 120 , The WPT ground unit 110 includes an inverter 213 which is adapted to generate an alternating current with a charging field frequency from a direct current (eg at a direct voltage of approximately 500 V). Furthermore, the WPT ground unit includes 110 the primary coil 111 (commonly referred to as inductive unit) and a primary capacitor 212 (commonly referred to as capacitive unit). It is also in 2 an example of a filter 214 the WPT ground unit 110 shown. The WPT ground unit 110 thus includes a series resonant circuit (also referred to herein as the primary resonant circuit), the resonant frequency of the total capacitance C (in particular the capacitance of the capacitor 212 ) and the total inductance L (in particular the inductance of the primary coil 111 ) when

results. The charging field frequency is preferably close to the resonance frequency f ₀ , to the highest possible primary current through the primary coil 111 to generate (by a resonance). A high primary current is typically required because the coupling factor k 230 between primary coil 111 and secondary coil 121 due to the large air gap 130 is relatively small, z. Eg k ~ 0.1.

Analogously, the WPT vehicle unit includes 120 a resonant circuit (also referred to here as secondary resonant circuit), which consists of the secondary coil 121 (commonly referred to as inductive unit) and a secondary capacitor 222 (generally referred to as capacitive unit) is formed. The resonant frequency of this secondary resonant circuit is preferably at the resonant frequency of the primary resonant circuit of the WPT ground unit 110 adapted to achieve the best possible energy transfer. It is also in 2 a filter capacitor 224 , a rectifier 101 and an energy store to be charged 103 shown.

The effective inductances L ₁ , L _{2 of} the primary coil 111 and the secondary coil 121 depend on the arrangement of the primary coil 111 relative to the secondary coil 121 from. In particular, the effective inductance L _{1 of} the primary coil depends 111 or the effective inductance L _{2 of} the secondary coil 121 the size of the underbody clearance 130 and / or from a transverse offset of the primary coil 111 to the secondary coil 121 from. A changing effective inductance leads to a changing resonant frequency of the primary resonant circuit. The control of the primary coil 111 should be adjusted accordingly for optimal energy efficiency. In particular, an adaptation of the charging field frequency, an adaptation of a matching network (eg of the filter 214 ) and / or an adjustment of the voltages.

The relative positioning between primary coil 111 and secondary coil 121 can be like in 3a z. B. by Cartesian coordinates X, Y, Z are described. The Z-coordinate gives the size of the underbody clearance 130 at. The X and Y coordinates describe the transverse offset of the primary coil 111 to the secondary coil 121 ,

Die Parameter L₁, L₂, k 331 sind dabei Funktionen der relativen Position zwischen Primärspule 111 und Sekundärspule 121, d. h. Funktionen von x, y, z.The inductive coupling system between primary coil 111 and secondary coil 121 can z. B. by a T-equivalent circuit diagram (see 3b ) are described or modeled. This model 330 indicates as a parameter 331 the effective inductance L _{1 of} the primary coil 111 , the effective inductance L _{2 of} the secondary coil 121 and the coupling factor k (where

The parameters L ₁ , L ₂ , k 331 are functions of the relative position between the primary coil 111 and secondary coil 121 , ie functions of x, y, z.

3c shows exemplary gradients / maps 300 . 310 . 320 for the parameters k, L ₁ , L ₂ 331 , These curves / maps 300 . 310 . 320 can be determined in advance for a specific inductive coupling system. In particular, for a particular combination of WPT ground unit 110 and WPT vehicle unit 120 or for a particular WPT ground unit combination 110 and vehicle type the gradients 300 . 310 . 320 for the parameters k, L ₁ , L ₂ 331 be measured. These courses 300 . 310 . 320 can then each be approximated by a mathematical function, in particular by an analytical function. In other words, the measured parameter maps k (x, y, z) 300 , L ₁ (x, y, z) 310 and L ₂ (x, y, z) 320 can each be approximated by a mathematical function P _k (x, y, z), P _L1 (x, y, z) and P _L2 (x, y, z). For example, the parameter maps can be approximated by polynomials. The mathematical functions can z. By linear regression based on the three-dimensional parameter maps 300 . 310 . 320 be determined. The mathematical functions P _k (x, y, z), P _L1 (x, y, z) and P _L2 (x, y, z) describe the desired parameter values of a model 330 an inductive coupling system.

To determine the mathematical function for a parameter z. B. in the development of the inductive coupling system, the actual parameter values of the parameter at as many positions (x, y, z) or for as many values of the position variables are detected. From this data, the mathematical function for the parameter can then be determined. For this purpose (depending on the functional class used, i.e. depending on the type of function used), linear or non-linear regression and / or dimensional reduction techniques may be used. In particular, methods from the field of "machine learning" can be used. For example, a neural network can be used as the type of function and trained on the basis of the measured data. The learned neural network (i.e., the mathematical function) for a parameter may then indicate the desired parameter value of the parameter for a particular position.

While positioning a vehicle 100 above the primary coil 111 a WPT ground unit 110 may be the actual parameter values k ⁽ⁱ⁾ , L ₁ ⁽ⁱ⁾ , L ₂ ^{(i) of} the model 330 an inductive coupling system are measured. For this purpose, z. In the WPT ground unit 110 an AC voltage U ₁ can be effected with a certain angular frequency ω. It may then be the primary current I ₁ in the WPT ground unit 110 , and the secondary current I ₂ and the voltage U ₂ in the WPT vehicle unit 120 be measured (as measurable electrical quantities 332 of the model 330 , Especially if the vehicle 100 relative to the WPT ground unit 110 moved, while doing the measurements on the WPT ground unit 110 and at the WPT vehicle unit 120 time-synchronized. For this purpose, the measurements can be made on the WPT ground unit 110 and at the WPT vehicle unit 120 be timestamped. This can be z. B. over WLAN by means of TSF timestamp ( IEEE 802.11y , HW for transit time measurement).

From the current and voltage measurements of the measurable quantities 332 in the WPT ground unit 110 and in the WPT vehicle unit 120 can then z. B. with the following system of equations of the model 330 out 3b the actual parameter values k ⁽ⁱ⁾ , L ₁ ⁽ⁱ⁾ , L ₂ ^{(i) of} the inductive coupling system are determined:

It may possibly be assumed that due to the high quality of the coils 111 . 121 (R _i << jωL _i ) holds, so that the resistors R _i 332 of the model 330 can be neglected.

• • Information in Bezug auf die relative Ist-Position (d. h. auf in Bezug auf die Ist-Werte von x, y, z) zwischen Primärspule 111 und Sekundärspule 121;
• • Information in Bezug auf einen Defekt der WPT-Bodeneinheit 110 und/oder der WPT-Fahrzeugeinheit 120; und/oder
• • Information in Bezug auf ein induktiv störendes Objekt zwischen der Primärspule 111 und der Sekundärspule 121.

On the basis of the actual parameter values k ⁽ⁱ⁾ , L ₁ ⁽ⁱ⁾ , L ₂ ⁽ⁱ⁾ the parameter 331 of the model 330 the inductive coupling system, and _k on the basis of mathematical functions P (X, Y, Z), P _L1 (X, Y, Z) and P _L2 (X, Y, Z) for the target parameter values of the parameters 331 of the model 330 of the inductive coupling system information can be determined with respect to the coupling system. Exemplary information regarding the coupling system is:

• Information relating to the relative actual position (ie with respect to the actual values of x, y, z) between the primary coil 111 and secondary coil 121 ;
• • Information regarding a defect of the WPT ground unit 110 and / or the WPT vehicle unit 120 ; and or
• • Information relating to an inductively disturbing object between the primary coil 111 and the secondary coil 121 ,

For example, the actual position of the vehicle 100 relative to the WPT ground unit 110 be determined. For this purpose, a cost function J ⁽ⁱ⁾ (x, y, z) can be formulated and optimized, the cost function depending on the actual parameter values and on the mathematical functions for the desired parameter values. For example, the cost function J ⁽ⁱ⁾ (x, y, z) may be designed to reduce the quadratic deviation between corresponding actual parameter values and desired parameter values, ie

• • Es kann der Start-Quadrant aus einem Positionierungsvorgang vermerkt werden (z. B. wenn die Start-Position des Fahrzeugs 100 bekannt ist), und bei der Optimierung der Kostenfunktion berücksichtigt werden.
• • Es kann für alle Quadranten simultan eine Optimierung der Kostenfunktion vorgenommen werden, um im Laufe eines Positionierungsvorgangs den wahrscheinlichsten Quadranten zu ermitteln (nach dem Prinzip der Sequentiellen Monte Carlo, SMC, Methode bzw. nach dem Prinzip von Partikel-Filtern).
• • Es können ein oder mehrere zusätzliche Sensoren bzw. Messspulen verwendet werden, um die Quadranten zu ermitteln.

The cost function J ⁽ⁱ⁾ (x, y, z) can z. B. optimized by using a gradient method (in particular minimized). In this case, the cost function typically has one or more local minima (in particular due to a symmetrical structure of the coupling system (for example with regard to the X and / or the Y axis)). It may be that, due to local minima, the actual position of the vehicle 100 can not be determined clearly. In particular, it may not be possible to determine in which quadrant of the X / Y sub-coordinate system the vehicle is located 100 relative to the WPT ground unit 110 located. These ambiguities can z. B. can be resolved as follows:

• • The start quadrant can be noted from a positioning process (eg when the vehicle's starting position is 100 is known), and be taken into account in the optimization of the cost function.
• • It is possible to optimize the cost function for all quadrants simultaneously in order to determine the most probable quadrant in the course of a positioning process (according to the principle of Sequential Monte Carlo, SMC, method or according to the principle of particle filters).
• • One or more additional sensors or measuring coils can be used to determine the quadrants.

Typically, a coupling system for the inductive charging of a vehicle includes further sensor elements, such. B. measuring coils for detecting foreign bodies in the air gap between the primary coil 111 and the secondary coil 121 , It is also possible to determine characteristic diagrams of parameters for these additional coils. For example, the WPT ground unit 110 have one or more additional coils L _A , L _B , L _C , and L _D , with the secondary coil 120 each form a coupling system. It can then z. B. the maps of mutual inductances M _{2A, B, C, D,} from L ₂ to L _A , L _B , L _C , and L _{D are} measured as desired parameter values and approximated by mathematical functions. The mutual inductances have a high dependence on the offset of the secondary coil 121 on. The mutual inductances result from the voltages U _{A, B, V, D} / L ₂ and are thus relatively easy to determine. During a positioning process, actual parameter values for the mutual inductances can then be determined. Furthermore, the deviations between the actual parameter values and the mathematical functions for the desired parameter values can be included in the cost function J ⁽ⁱ⁾ (x, y, z). Thus, local minima of the cost function J ⁽ⁱ⁾ (x, y, z) can be avoided.

The measured actual parameter values k ⁽ⁱ⁾ , L ₁ ⁽ⁱ⁾ , L ₂ ^{(i) are} the parameters 331 of the model 330 the inductive coupling system and the mathematical functions P _k (x, y, z), P _L1 (x, y, z) and P _L2 (x, y, z) for the target parameter values of the parameters 331 of the model 330 of the inductive coupling system can also be used for a physical change of the inductive coupling system (eg due to a defect of a coil 111 . 121 of the coupling system and / or due to an object between the primary coil 111 and secondary coil 121 ) to detect. For such a diagnosis of a physical change of the inductive coupling system, an ambiguity of the cost function J ⁽ⁱ⁾ (x, y, z) is typically irrelevant.

It can be an initial position of the vehicle 100 relative to the WPT ground unit 110 , ie x ₀ , y ₀ , z ₀ , be known. The starting position of the vehicle 100 can z. B. determined by another positioning method (eg, an image-based positioning method). Alternatively or additionally, the starting position x ₀ , y ₀ , z _{0 of} the vehicle 100 relative to the WPT ground unit 110 has been determined by minimizing the cost function J ⁽ⁱ⁾ (x, y, z) (eg at the beginning of a loading process). The minimum J ₀ = J ⁽ⁱ⁾ (x ₀ , y ₀ , z ₀ ) is then known.

The actual parameter values L ₁ ⁽ⁱ⁾ , L ₂ ^{(i) of} the inductive coupling system can then be measured (eg at a later time and possibly again), and by optimizing the cost function J ⁽ⁱ⁾ ( x, y, z) the actual position x _i , y _i , z _{i of} the vehicle and the actual value of the minimum of the cost function J _i = J ⁽ⁱ⁾ (x _i , y _i , z _i ) are determined. Due to a change in the coupling system, the actual position x _i , y _i , z _{i can} deviate from the starting position x ₀ , y ₀ , z ₀ .

For example, then the radial deviation in the three-dimensional (3D) space (x _i - x ₀ ) ² + (y _i - y ₀ ) ² + (z _i - z ₀ ) ² can be determined, and it can be checked whether this radial 3D deviation is greater or less than a maximum allowable radial 3D deviation r _max .

If the radial 3D deviation is greater than the maximum permissible radial 3D deviation r _max , it may be possible to stop an inductive charging process.

Alternatively or additionally, a radial deviation in the X / Y plane (ie in two-dimensional, 2D, space) can be determined, and a deviation in the Z-direction can be determined, ie (x _i -x ₀ ) ² + (y _i - y ₀ ) ² and (z _i - z ₀ ). These deviations can be compared with respective maximum permissible deviations. So z. For example, it can be seen that a significant change in the Z direction but no substantial change in the X / Y plane has resulted. Such a change in the Z direction can z. B. on a load or a discharge of the vehicle 100 based. The operating point of the inductive charging system (eg the frequency of the inductive charging field used) can then be changed in order to adapt the inductive charging process to the changed underbody clearance 130 (and thus to the changed resonant frequency of the inductive coupling system) adapt. Other sensors (eg a load sensor) of the vehicle may also be used 100 be taken into account to load or unload the vehicle 100 to confirm. Can the loading or unloading of the vehicle 100 can not be confirmed, so it may be a write off of the loading (for security reasons).

Alternatively or additionally, the actual value of the minimum of the cost function J _i = J ⁽ⁱ⁾ (x _i , y _i , z _i ) can be considered, and with a maximum allowable threshold J _max and / or with the output value J ₀ = J ⁽ⁱ⁾ (x ₀ , y ₀ , z ₀ ). If the actual value J _{i is} too high, then it can be concluded that a defect of the coupling system is present and / or that an object is located between the coils 111 . 121 of the coupling system is located. It can then be canceled, the inductive charging.

4 shows an exemplary course 400 the cost function J ⁽ⁱ⁾ (x, y, z) for an intact coupling system and an exemplary course 401 the cost function J ⁽ⁱ⁾ (x, y, z) for an impaired coupling system. It is off 4 it can be seen that the cost function is impaired by a defect and / or by a disturbing object, so that the minimum of the cost function shifts to another position (and a different actual position is determined) and so that the minimum of the cost function is increased Value. Both facts can be used (separately or in combination) to detect a defect and / or a disturbing object.

It can thus be the relative output position x ₀ , y ₀ , z _{0 are} determined, for. B. from previously determined coil parameter fields. Different information sources can be used. Furthermore, automatically determined data fields of the inductive coupling system can be taken into account, which have been converted into parameterizable functions by means of regression calculation and are therefore relatively easy to evaluate.

On the basis of the parameterizable functions, an actual position x _i , y _i , z _{i can then be} estimated. The estimation position can be used to switch off (possibly in conjunction with vehicle height data) a charging process, to detect defects, to detect foreign bodies in the air gap, to optimize the energy transfer and / or to optimize other functions such. B. the threshold value adjustment of a sensor array for foreign body detection can be used.

5 shows a flowchart of an exemplary method 500 for determining information relating to an inductive coupling system for inductively charging an electrical energy storage device of a vehicle 100 , The inductive coupling system comprises a primary coil 111 (eg as part of a WPT ground unit 110 ) and a secondary coil 121 (eg as part of a WPT vehicle unit 120 of the vehicle 100 ), which are magnetically coupled together. For an energy-efficient charging process, it is advantageous that the degree of coupling between the primary coil 111 and the secondary coil 121 as high as possible. This requires a precise positioning of the secondary coil 121 above the primary coil 111 ,

The procedure 500 includes determining 501 of actual parameter values of several parameters 331 a model 330 of the inductive coupling system. The model 330 The inductive coupling system can thereby measurable physical quantities 332 of the inductive coupling system as a function of the parameters 331 describe. In other words, the model can 330 of the inductive coupling system a relationship between measurable physical quantities 332 and the parameters 331 (eg idealized component) of the model 330 describe. The measurable physical quantities 332 can z. For example, voltages and / or currents on the WPT ground unit 110 and / or the primary coil 111 or at the WPT vehicle unit 120 and / or the secondary coil 121 include. The parameters 331 may include inductive parameters, the inductive properties of the coupling system such. B. the (effective) Induktivtäten L ₁ , L _{2 of} the primary coil 111 and / or the secondary coil 121 or describe the degree of coupling k. The model 330 can z. B. a T-replacement model of a transformer with the primary coil 111 and the secondary coil 121 include.

The actual parameter values of the parameters 331 can be measured by measuring values of measurable physical quantities 332 be determined. For this purpose, from the measured values of the measurable physical quantities 332 using the model 330 of the inductive coupling system, the actual parameter values of the parameters 331 be determined.

The procedure 500 further includes determining 502 information related to the inductive coupling system based on the actual parameter values and based on mathematical functions for desired parameter values of the parameters 331 , In particular, for each parameter 331 be provided a separate mathematical function. This shows the mathematical function for a parameter 331 the target parameter values of the parameter 331 as a function of a relative position x, y, z between the primary coil 111 and the secondary coil 121 of the inductive coupling system.

In particular, the relative actual position x _i , y _i , z _i between the primary coil 111 and the secondary coil 121 be determined as information relating to the inductive coupling system. For this purpose, a cost function J ⁽ⁱ⁾ (x, y, z) can be minimized, which depends on a (possibly quadratic) deviation between the actual parameter values and the desired parameter values. The desired parameter values are thereby determined in an efficient manner on the basis of the mathematical functions

The procedure described in this document 500 makes it possible to efficiently detect defects in a coil system 111 . 121 to detect. Furthermore, a relative offset between the primary and secondary coils 111 . 121 be monitored (possibly also in dependence on a known vehicle vertical movement). In addition, parameters can 331 of the inductive charging system can be determined in a precise manner, so that an operating point of the inductive charging system can be optimized to increase the efficiency of the inductive charging system. It may be possible settings of the circuits of the WPT ground unit 110 and / or the WPT vehicle unit 120 be adjusted.

The procedure 500 can with a relatively low computational effort in the vehicle 100 be implemented, since previously determined mathematical functions can be used. In the context of the determination of the mathematical functions (eg in a regression calculation), statistical measurement errors of the characteristic diagrams for the parameters 331 be smoothed the inductive coupling system (in particular, an under- and overfitting can be avoided). The mathematical functions for describing the desired parameter values of the inductive coupling system are typically of the vehicle type 100 dependent. By providing type-dependent mathematical functions, the procedure can 500 be efficiently transferred to different types of vehicles.

The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended to illustrate only the principle of the proposed methods, apparatus and systems.

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 non-patent literature

• IEEE 802.11y [0050]

Claims (11)

Procedure ( 500 ) for determining information relating to an inductive coupling system for inductively charging an electrical energy store of a vehicle ( 100 ), wherein the inductive coupling system is a primary coil ( 111 ) and a secondary coil ( 121 ) magnetically coupled together; the method ( 500 ), - determining ( 501 ) of actual parameter values of several parameters ( 331 ) of a model ( 330 ) of the inductive coupling system; and - determining ( 502 ) of information relating to the inductive coupling system based on the actual parameter values and on the basis of mathematical functions for desired parameter values of the parameters ( 331 ); where the mathematical function for a parameter ( 331 ) the nominal parameter values of the parameter ( 331 ) as a function of a relative position between the primary coil ( 111 ) and the secondary coil ( 121 ) of the inductive coupling system indicates. Procedure ( 500 ) according to claim 1, wherein - the method ( 500 ), acquisition of maps ( 300 . 310 . 320 ) for the parameters ( 331 ) of the inductive coupling system; and - the map ( 300 . 310 . 320 ) for a parameter ( 331 ), Values of the parameter ( 331 ) as a function of the relative position between the primary coil ( 111 ) and the secondary coil ( 121 ); and - the method ( 500 ), determining the mathematical function for the parameter ( 331 ) by approximation, in particular by means of linear regression, of the characteristic map for the parameter ( 331 ). Procedure ( 500 ) according to one of the preceding claims, wherein the mathematical function, - comprises an analytical function; A desired parameter value of a parameter ( 331 ) as a function of different position variables for describing the relative position between the primary coil ( 111 ) and the secondary coil ( 121 ) indicates; The position variables, in particular distances between the primary coil ( 111 ) and the secondary coil ( 121 ) in Cartesian coordinates; - is continuous with respect to a position variable; - is continuously derivable according to a position variable; and / or - a polynomial. Procedure ( 500 ) according to any one of the preceding claims, wherein the determining ( 502 ) of information relating to the inductive coupling system, reducing a cost function indicating a deviation of the actual parameter values from the desired parameter values given by the mathematical functions by varying the relative position between the primary coil ( 111 ) and the secondary coil ( 121 ). Procedure ( 500 ) according to claim 4, wherein said determining ( 502 ) of information relating to the inductive coupling system, - determining a relative actual position between the primary coil ( 111 ) and the secondary coil ( 121 ), which reduces, in particular minimizes, the cost function; and / or - determining a minimum value of the cost function. Procedure ( 500 ) according to one of the preceding claims, wherein the information relating to the inductive coupling system contains information relating to a relative actual position between the primary coil ( 111 ) and the secondary coil ( 121 ). Procedure ( 500 ) according to one of the preceding claims, wherein - the method ( 500 ), determining a relative output position between the primary coil ( 111 ) and the secondary coil ( 121 ); and - the information relating to the inductive coupling system is also determined on the basis of the relative output position. Procedure ( 500 ) according to claim 7 with reference to claim 4, wherein the method ( 500 ), - detecting that the relative actual position deviates from the relative starting position, although the vehicle ( 100 ) has not been moved between determining the relative home position and determining the relative current position; and - in response, canceling an inductive charging of the vehicle electrical energy storage ( 100 ) via the inductive coupling system. Procedure ( 500 ) according to one of the preceding claims, wherein the parameters ( 331 ) a degree of coupling between the primary coil ( 111 ) and the secondary coil ( 121 ) and / or inductance values of the primary coil ( 111 ) and the secondary coil ( 121 ) Show. Procedure ( 500 ) according to one of the preceding claims, wherein - the inductive coupling system additionally comprises a measuring coil; and - the parameters ( 331 ) a parameter ( 331 ), which depends on a degree of coupling between the measuring coil on the one hand and the primary coil ( 111 ) and / or the secondary coil ( 121 ) on the other hand. Procedure ( 500 ) according to one of the preceding claims, wherein - the model ( 330 ) of the inductive coupling system measurable physical quantities ( 332 ) of the inductive coupling system as a function of the parameters ( 331 ) describes; - the model ( 330 ) of the inductive coupling system comprises an electrical equivalent circuit of the inductive coupling system; - the model ( 330 ) of the inductive coupling system comprises a plurality of idealized electrical components, in particular idealized coils; - the parameters ( 331 ) describe the properties of the idealized electrical components, in particular the inductances; - the model ( 330 ) an equivalent circuit, in particular a T-equivalent circuit, of a transformer with the primary coil ( 111 ) and the secondary coil ( 121 ); and / or - the measurable physical quantities ( 332 ) Currents and / or voltages at the primary coil ( 111 ) and the secondary coil ( 121 ).

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