Method for automatically releasing an energy transmission by means of an inductive energy transmission device for a motor vehicle, and inductive energy transmission device

Abstract

A method for automatically releasing an energy transmission by means of an inductive energy transmission device (11) for a motor vehicle (10), involving a ground module (16) and a vehicle module (12), determines a coupling value by means of coupling measurements. A charging release range (26) above a coupling base value is divided into an inner, first coupling range (30) above a first coupling limit value and an outer, second coupling range (32). Adjacently thereto, a third coupling range (36) is defined above a second coupling limit value which is below the coupling base value. The relative position is monitored before and after the parking position is reached. The charging release process takes place if, in a parking position, the coupling value is in the first coupling range, or the coupling value is in the second coupling range and the first coupling range has been passed through previously. In the event of position changes, it remains active in the second or third coupling range and is deactivated outside of the third coupling range. This results in a multi-stage hysteresis which avoids toggling and keeps the charging process robust in the event of small relative movements.

Description

[0001] Method for automated release of energy transfer by means of an inductive energy transfer device for a motor vehicle and an inductive energy transfer device

[0002] A method for the automated release of energy transfer by means of an inductive energy transfer device for a motor vehicle, comprising a stationary ground module and a vehicle module, wherein a coupling value is determined by means of coupling measurements between the primary unit and the secondary unit, and a charging release range is defined in which the coupling value is above a coupling base value, wherein charging is released when the coupling value is within the charging release range at a parked position of the vehicle. The invention further relates to an inductive energy transfer device for an electric vehicle.

[0003] Inductive power transfer devices of this type are generally used for the inductive charging of an energy storage device in an electric vehicle. In one operating variant, a magnetic field is generated by a first coil in a floor module, which induces a current in a second coil of an adjacent vehicle module. This current is then used to charge the vehicle's electrical energy storage device. In a second operating variant, the vehicle charging system can also transfer electrical energy stored in the vehicle's energy storage device to the floor module, for example, to power electrically connected consumers or even to feed the energy into the power grid.

[0004] The ground module is typically fixed to the ground. The vehicle module is typically mounted on the underbody of a vehicle. The vehicle module must be positioned largely above the ground module to ensure efficient energy transfer. Relevant standards and norms (IEC 61980) for automated charging systems specify a defined positioning range between the vehicle module and the ground module. Positioning systems are typically based on an ultrawideband (UWB) system or a differential-integral positioning (DIPS) system.

[0005] Positioning the vehicle near the boundaries of the positioning area, both for enabling and aborting charging, results in a less robust charging process in the field. An automated inductive charging system therefore requires the vehicle to be positioned within the positioning area, and positioning at the edge of this area can lead to a lack of robustness in the charging process. In particular, an unintentional, minor movement of the vehicle, for example during loading or unloading, can cause the energy transfer process to be interrupted, or a so-called "toggling" phenomenon can occur, i.e., a repeated switching between energy transfer and abort.

[0006] The object of the invention is to avoid such effects and to ensure robust energy transfer.

[0007] The invention is based on the idea that a multi-stage hysteresis in the positioning process of automated charging increases the robustness of the charging process, prevents charging interruptions in the event of expected relative movements, and avoids user interaction during the charging process.

[0008] The invention is defined by the features of the independent claims. Advantageous further developments and embodiments are the subject of the dependent claims. Further features, applications, and advantages of the invention will become apparent from the following description and the explanation of exemplary embodiments of the invention illustrated in the figures.

[0009] The task is solved by dividing the charging enable area into an inner first coupling area with a coupling value greater than a first coupling limit that is above the coupling base value, and an outer second coupling area. Adjacent to the charging enable area, a third coupling area with a coupling value greater than a second coupling limit that is below the coupling base value is defined outside the charging enable area. The relative position is monitored before reaching the parking position, and charging enable is activated after reaching the parking position if the coupling value at the parking position is within the first coupling area. Furthermore, charging enable is activated if the coupling value at the parking position is within the second coupling area and the relative position crossed the first coupling area before reaching the parking position.The charging release remains activated when the parking position changes if the coupling value is within the second coupling range or the third coupling range, and,

[0010] - charging is deactivated when the parking position is changed if the coupling value at the new parking position is outside the third coupling area.

[0011] In the context of this invention, "charging enable" means that energy transfer between the ground module and the vehicle module can occur, but only takes place when the energy transfer is activated by a separate control command. Activating charging enable is therefore not equivalent to actual energy transfer. However, deactivating charging enable necessarily terminates the energy transfer.

[0012] The activation of the actual energy transfer can be manual or automated. In one application, the energy transfer process can begin immediately when charging is enabled according to the inventive method, or communication can be initiated with the vehicle driver requesting whether the energy transfer should take place immediately or at a later time. Since energy costs (EUR / kWh) can vary depending on the time of day, it can be advantageous to carry out the energy transfer at a time when energy costs are relatively low. Similarly, if electrical energy is to be drawn from the energy storage system and fed into the connected power grid, this should ideally occur at a time when the feed-in tariff is as high as possible.

[0013] The invention thus provides a multi-stage hysteresis with four conditions for enabling charging, which takes into account the specific physical characteristics of the electromagnetic field, whose coupling behavior is approximately circular in two dimensions and approximately hemispherical in three dimensions. This ensures more robust energy transfer, avoiding unwanted switching on and off of the energy transfer. In particular, it reliably prevents so-called "toggling," i.e., repeated, rapid switching on and off of the charging process. Furthermore, it leads to increased robustness in the event of small relative movements of the vehicle expected during the charging process.

[0014] By applying the hysteresis according to the invention with four conditions, the number of necessary charging interruptions due to relative movements of the vehicle can be significantly reduced if only the coupling measurement, and not the positioning range, is considered as the criterion. This is possible because the magnetic coupling is a direct indicator of the charging capability. If the vehicle moves briefly outside the positioning range (e.g., during loading / unloading), the charging process does not have to be interrupted as long as the magnetic coupling remains sufficiently high. The inductive charging system can still detect if the vehicle rolls away by means of a change in the coupling value, so that the charging process can be interrupted quickly enough.

[0015] Preferably, according to the invention, the coupling behavior is mathematically modeled taking into account the primary and secondary coil currents. The value determined in this way is identical to the actual magnetic coupling.

[0016] The first coupling limit of the first coupling region is preferably between 1 and 15% above the coupling baseline value. The first coupling limit is the coupling value that can be achieved precisely at the boundary between the inner first coupling region and an outer second coupling region.

[0017] The second coupling limit defines the outer boundary of the third coupling region, which lies outside the second coupling region, wherein the second coupling limit is smaller than the coupling base value. The second coupling limit of the third coupling region is preferably between 1 and 10% below the coupling base value.

[0018] According to an advantageous embodiment of the invention, the coupling baseline value is a limit at which energy transfer at maximum power is just barely possible. Since the coupling behavior of an inductive charging system can be determined in various ways, e.g., based on the magnetic flux density, the mutual induction, or the coil currents, different coupling values ​​result depending on the measurement method and coil topology used, and these values ​​are not comparable. For this reason, according to the invention, the hysteresis is described relative to a coupling baseline value. The coupling baseline value corresponds to the coupling that just barely allows energy transfer at maximum power. Viewed two-dimensionally, this coupling baseline value defines a range.

[0019] According to an advantageous embodiment of the invention, a fourth coupling area is located adjacent to and outside the third coupling area. Following an activated charging enable and a subsequent controlled deactivation of the charging process (sleep phase), the charging process is reactivated (end of the sleep phase). If the parking position has changed during the deactivation phase, a renewed charging enable occurs only if the coupling value at the new parking position lies within one of the four coupling areas. A controlled deactivation of the charging process means a deliberate shutdown of the charging process, whether performed manually or by a timer. Therefore, only a coupling value after the end of a sleep phase that lies within the fourth coupling area leads to a renewed charging enable.

[0020] The third coupling limit defines the outer boundaries of the fourth coupling region, which lies outside the third coupling region. The third coupling limit of the fourth coupling region is preferably at most 30% below the basic coupling value.

[0021] According to an advantageous embodiment of the invention, the coupling areas are round or oval.

[0022] Another aspect of the invention relates to an inductive energy transfer device for an electric vehicle for carrying out the method described above, comprising a vehicle module, a unit for continuously detecting the relative position between the vehicle module and a ground module, a control unit in which the coupling areas are stored, and a switching unit for activating and deactivating the energy transfer.

[0023] Further advantages, features, and details will become apparent from the following description, in which at least one embodiment is described in detail with reference to the drawings. Identical, similar, and / or functionally equivalent parts are identified by the same reference numerals.

[0024] They show:

[0025] Figure 1: a schematic representation of a motor vehicle with an inductive charging system

[0026] Energy transmission device;

[0027] Figure 2: a representation of the coupling regions according to the invention; Figure 3: a schematic representation of the hysteresis during activation of the

[0028] Charging enabled;

[0029] Figure 4: a schematic representation of hysteresis during deactivation of the

[0030] Charging enabled;

[0031] Figure 5: a schematic representation of the first and second

[0032] Coupling area with various exemplary parking positions;

[0033] Figure 6: a schematic representation of the release area and the third

[0034] Coupling area with various exemplary parking positions;

[0035] Figure 7: a schematic representation of the release area, the third and fourth coupling areas with various exemplary parking positions.

[0036] Figure 1 schematically depicts an electrically powered motor vehicle 10, which includes an inductive energy transfer device 11 comprising a vehicle module 12 that can be inductively coupled to a ground module 16 arranged on a ground 14. For this purpose, the vehicle module 12 and the ground module 16 each have coils to transfer electrical energy by means of inductive coupling either from the ground module 16 via the vehicle module 12 to a vehicle-side energy storage device 18 (preferably a battery) or vice versa. The ground module 16 is connected to a local or regional power supply network via cables (not shown). A sensor arrangement 20, shown only schematically, is provided to detect the relative position between the vehicle module 12 and the ground module 16. The sensor arrangement 20 is configured to determine the magnetic coupling between the ground module 16 and the vehicle module 12.The sensor arrangement 20 is connected to a control unit 22 in which the coupling limits according to the invention are stored, which define the coupling ranges.

[0037] When the sensor arrangement 20 detects a magnetic coupling between vehicle module 12 and ground module 16 that meets individual criteria of the invention, the control unit 22 activates a charging enable. This means that if the control unit 22 receives the instruction via external communication that energy transfer should take place, and at the same time it is determined that the vehicle is stationary and the enable criteria according to the invention are met, the control unit 22 activates a switching unit 24, which enables energy transfer from the ground module 16 to the energy storage device 18 or vice versa. Figure 2 shows the coupling areas according to the invention in relation to a circular charging enable area 26 with a center point 28.The charging release area 26 corresponds to the area within which energy transfer at maximum power is possible; thus, the dashed line 26 marks the limit at which energy transfer at maximum power is just barely possible.

[0038] According to the invention, the charging release area 26 is divided into an inner, first coupling area 30 and a contrasting outer, second coupling area 32, which are separated from each other by a first boundary 34 (shown with dotted lines). In the illustrated embodiment with a circular charging release area 26, the first coupling area 30 is also circular, while the second coupling area 32 forms a closed circle enclosing the first coupling area 30. Outside the charging release area 26, a third, circular coupling area 36 and, outside this, a fourth, circular coupling area 38 are defined, which are separated by a second boundary line 39 (shown with dashed lines). The fourth coupling area 38 is bounded externally by the third boundary line 40 shown.

[0039] When the motor vehicle 10 has assumed a parking position, the relative position between ground module 16 and vehicle module 12 is represented as a point in the XY coordinate system according to Figure 2, and the consequences for the charging release depend on where or in which of the coupling areas 30, 32, 36, 38 the parking position is located.

[0040] Figure 3 schematically illustrates how the hysteresis occurs when charging is enabled. The horizontal axis shows the distance of the parking position from the zero point or center point 28, both in the vehicle's longitudinal direction (X-direction) and in the vehicle's transverse direction (Y-direction), as this is a schematic representation and the principle applies equally to both directions. The vertical axis shows whether charging is enabled (1) or not (0).

[0041] If the vehicle 10 stops at parking position P1, which lies outside the release area 26 (movement along the solid line), upon first entering the release area 26, no charging is authorized. Similarly, no charging is authorized at parking position P2, which is within the standardized release area 26 but outside the boundary line 34, i.e., in the second coupling area 32. However, charging is authorized at parking position P3, which lies within the first coupling area 30.

[0042] However, if the vehicle 10 was moved through the first coupling area 30 before reaching parking position P2 (movement along the dashed line), then charging will still be enabled at parking position P2, but not at parking position P1.

[0043] Figure 4 schematically illustrates how hysteresis occurs when charging is enabled. The horizontal axis shows the distance of the parking position from the zero point 28, both in the vehicle's longitudinal direction (X-direction) and in the vehicle's transverse direction (Y-direction), as this is a schematic representation and the principle applies equally to both directions. The vertical axis shows whether charging is enabled (1) or not (0).

[0044] If, according to Fig. 3, the charging release has been activated (point P3 and possibly P2) and the vehicle has moved and is located at point P4, which lies in the third coupling area 36 but outside the normalized release area 26, the charging release remains activated.

[0045] If the parking position is located at point P5 in the fourth coupling area 38, the charging release remains active only if the inductive energy transfer device 11 was previously in a so-called sleep phase, i.e., energy transfer was prevented due to external intervention despite the activated charging release.

[0046] With reference to Figure 5, the activation of the charging release is further explained. Assume that the vehicle 10 enters the effective area of ​​the ground module 16 in such a way that it comes to a standstill at the parking position [A]. This position lies within the second coupling area 32, which, although it lies within the standardized release area 26, nevertheless, according to the invention, the charging release is not activated.

[0047] If, however, vehicle 10 parks at parking position (B) which is located in the first coupling area 30, the charging authorization is activated.

[0048] If the vehicle 10 parks at parking position (C), which, like parking position [A], is within the second coupling area 32, but has previously crossed the first coupling area 30, the charging release is still activated, even though the vehicle is in the same second coupling area 32 as parking position [A].

[0049] If the vehicle 10 is parked at parking position [D], the charging release is not activated, as parking position [D] is outside the standardized release area 26.

[0050] If the vehicle 10 is parked at parking position [E], i.e. within the second coupling area 32, but has previously crossed the standardized release area 26, i.e., has driven backwards a bit, then the charging release is not activated.

[0051] If the vehicle 10 is parked at parking position (F), i.e. within the first coupling area 30, the charging authorization is activated regardless of the direction of entry.

[0052] If the vehicle 10 parks at parking position (G), i.e. within the second coupling area 32, after having previously crossed the first coupling area 30, the charging release is activated analogously to parking position (C).

[0053] With reference to Figure 6, the deactivation of charging authorization (charging abort) is further explained.

[0054] Assume that the vehicle 10 was positioned in the parking position (B) within the standardized release area 26, so that the charging release was activated. Due to a slight relative movement, which can be caused, for example, by loading or unloading the vehicle 10, the vehicle 10 is now in the parking position (A), which is also within the standardized release area 26, so that the charging release remains activated. It is also possible that the parking position of the vehicle 10 does not change at all, but an imprecision of the sensor arrangement 20 or the measurement results (e.g., due to temperature drift) suggests a slight change in the parking position. According to the invention, this is treated in the same way as actual movements of the vehicle 10.

[0055] If the vehicle has moved 10 to the parking position (H) which lies within the third coupling area 36, ​​the charging release remains activated.

[0056] However, if vehicle 10 has moved to parking position [J], which lies outside the third coupling area 36, ​​charging will be deactivated. If vehicle 10 has moved from parking position (B), for example by rolling away, to parking position [K], which lies outside the third coupling area 36, ​​charging will be deactivated.

[0057] Assuming that vehicle 10 was positioned at parking position (C) within the standardized release area 26 and has moved to parking position (L) within the third coupling area 36, ​​the charging release remains activated.

[0058] If, however, the vehicle 10 has moved from parking position (C) to parking position [N] which is outside the third coupling area 36, ​​the charging authorization is deactivated.

[0059] If the vehicle 10 has moved from parking position (C), for example by rolling away, to the parking position (K) which lies outside the third coupling area 36, ​​the charging authorization is deactivated.

[0060] With reference to Figure 7, the deactivation of charging authorization after a so-called sleep phase is further explained. A charging pause or sleep phase, in which energy transfer is interrupted by external signals despite activated charging authorization, can occur, for example, if the energy storage unit 18 is to be charged by means of its own photovoltaic system and this system does not supply sufficient energy at times.

[0061] During the charging break, relative movements of the parked vehicle may occur, for example due to loading and unloading of the vehicle, or temperature fluctuations may affect the tolerance chain of the sensor arrangement (20).

[0062] Assume that vehicle 10 was positioned at parking position (B) within the standardized release area 26 when the energy transfer was interrupted. If the vehicle subsequently moved to parking position (J), which is outside the third coupling area 36 but within the fourth coupling area 38, the charging release remains activated.

[0063] However, if the vehicle moves to the parking position [P] during the charging break, which is outside the fourth coupling area 36, ​​the charging authorization is deactivated.

[0064] The behavior corresponds to that shown in Figure 7 if the vehicle did not move during the charging pause, but moves after the charging pause has ended, i.e. after the start of the renewed energy transfer, by making slight movements to positions (J), [P] or [K], with the difference that the energy transfer is terminated.

[0065] Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

[0066] Reference symbol list

[0067] 10 motor vehicle

[0068] 11 inductive energy transfer device

[0069] 12 Vehicle module

[0070] 14 Floor

[0071] 16 floor module

[0072] 18 Energy storage

[0073] 20 Sensor arrangement

[0074] 22 Control unit

[0075] 24 switching unit

[0076] 26 Charging Release Area

[0077] 28 Center point

[0078] 30 inner, first coupling area

[0079] 32 outer, second coupling area

[0080] 34 first limit

[0081] 36 third coupling area

[0082] 38 fourth coupling area

[0083] 39 second boundary line

[0084] 40 third boundary line

Claims

Patent claims 1. Method for the automated release of energy transfer by means of an inductive energy transfer device (11) for a motor vehicle (10), which comprises a stationary ground module (16) and a vehicle module (12), wherein a coupling value is determined by means of coupling measurements between the ground module (16) and the vehicle module (12) and a charging release range (26) is defined in which the coupling value is above a coupling base value, wherein charging is released when the coupling value is within the charging release range at a parked position of the vehicle (10), characterized in that the charging release range (26) is subdivided into an inner first coupling range (30) with a coupling value that is greater than a first coupling limit value that is above the coupling base value, and an outer second coupling range (32). - adjacent to outside the charging release area (26) a third coupling area (36) is defined with a coupling value that is greater than a second coupling limit value that is below the coupling base value, wherein the relative position is monitored before reaching the parking position and after reaching the parking position - Charging is enabled if the coupling value at the parking position is within the first coupling area (30); furthermore, charging is enabled if the coupling value at the parking position is within the second coupling area (32) and the relative position has crossed the first coupling area (30) before reaching the parking position; charging remains enabled when the parking position changes if the coupling value is within the second coupling area (32) or the third coupling area (36); charging is disabled when the parking position changes if the coupling value at the new parking position is outside the third coupling area (36).

2. Method according to claim 1, characterized in that the coupling base value is a limit value at which energy transfer with maximum power is just possible.

3. Method according to claim 1, characterized in that a fourth coupling area (38) is located adjacent outside the third coupling area (36) with a coupling value that is greater than a third coupling limit value, wherein after an activated charging release and a subsequent controlled deactivation of the charging process, a reactivation of the charging process is to take place, and if the parking position has changed during the deactivation phase, a reactivation of the charging process only takes place if the coupling value at the new parking position is within one of the four coupling areas (30, 32, 36, 38).

4. Method according to claim 1 or 2, characterized in that the coupling areas (30, 32, 36, 38) are round or oval.

5. Method according to claim 1 or 2, characterized in that the first coupling limit is between 1 and 15% above the coupling base value.

6. Method according to claim 1, characterized in that the second coupling limit is between 1 and 10% below the coupling base value.

7. Method according to claim 1, characterized in that the third coupling limit is at most 30% below the coupling base value.

8. Method according to claim 1, characterized in that the fourth coupling limit is at most 30% below the basic coupling value and is smaller than the third coupling limit.

9. Inductive energy transfer device (11) for an electrically powered motor vehicle (10) for carrying out the method according to one of the preceding claims, comprising a vehicle module (12), a floor module (16), a sensor arrangement (20) for continuously detecting the coupling value of the inductive coupling between the vehicle module (12) and the floor module (16), a control unit (22) in which the coupling areas (30, 32, 36, 38) are stored, and a switching unit (24) for activating and deactivating the energy transfer.

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