WO2023180207A1

WO2023180207A1 - Apparatus and method for inductive charging of a high-voltage battery of a vehicle

Info

Publication number: WO2023180207A1
Application number: PCT/EP2023/056938
Authority: WO
Inventors: Robert Sterff; Andreas Hager; Matthias Kerler; Johannes Rarbach
Original assignee: pepper motion GmbH
Priority date: 2022-03-22
Filing date: 2023-03-17
Publication date: 2023-09-28
Also published as: DE102022106634A1

Abstract

Apparatus (100) for inductive charging, in particular of a high-voltage battery, comprising at least a DC/mid-frequency converter (12) arranged at a charging infrastructure device (50), a mid-frequency/DC converter (18) arranged in the vehicle (110), a coil system, comprising a first coil (14) and a second coil (16), wherein the first coil (14) is arranged at the charging infrastructure device (50) and the second coil (16) is arranged at the vehicle (110). The first coil (14) is electrically connected to the DC/mid-frequency converter (12) and the second coil (16) is electrically connected to the mid- frequency/DC converter (18). The first coil (14) is arranged in a vertical axis (112) above the vehicle (110), and the second coil (16) is arranged on a roof (114) of the vehicle (110). The coils (14, 16) can be brought together for charging until the coils (14, 16) lie one on another in positively locking fashion.

Description

Title

Apparatus and method for inductive charging of a high-voltage battery of a vehicle

Prior art

The invention relates to an apparatus and a method for inductive charging, in particular for inductive charging of a high-voltage battery of a vehicle.

Battery electric vehicles can be charged by means of conductive and inductive charging methods. In the case of conductive charging methods, the electrical energy is transferred into the vehicle via mechanical and galvanically connected contact sets. In the case of inductive charging methods, the energy is transferred without contact by way of a magnetic field from a primary coil, which is usually integrated in the ground underneath the vehicle, to a secondary coil situated in the vehicle.

Conductive charging is usually used in the case of commercial vehicles such as buses, for example, in which the capacity of the energy store in the vehicle is designed for an entire day’s use (round trip). In this case, preference is given to charging at night, which is carried out at central points during the pause in operation, preferably at the vehicle depot.

If a smaller energy store that is not designed for a complete round trip is used as a traction battery, use is made of the so called opportunity charger. In this case, the energy store has to be recharged during scheduled use on the route. In contrast to depot charging in a vehicle depot with possible intermediate charging, high charging powers and a pantograph charging system are necessarily employed. Besides opportunity charging on the route, this charging strategy additionally provides for recharging at the depot and also at turning points. In addition, selected stops with a relatively long stopping time can be designed as charging points with the aim of full charging.

Inductive charging is physically characterized by energy being transported by way of the magnetic field lines. A determining feature is that the magnetic flux permeates the spatial boundary between vehicle and charging infrastructure since transformer-based (galvanic) isolation of the electrical circuits is likewise present at different locations of the system, and is normatively demanded as well, in all other charging methods. In this regard, medium-voltage transformers can be used, for example, which have a plurality of low-voltage windings and in which each low-voltage winding supplies a charging power converter and thus a charging point. In this way, the charging points are normatively isolated from the electrical supply network and also from neighbouring charging points. In this specific case, the charging power converters no longer require further galvanic isolation within their architecture.

Inductive energy transfer systems are based on the principle of near-field magnetic coupling. A current which is variable over time in the primary coil generates a magnetic flux which is variable over time and which permeates the secondary coil situated at the vehicle. This magnetic flux generates an induced voltage and also a current which is variable over time in the secondary coil. The magnetic field generated in turn by the current is superposed with that of the primary coil. Typical power ranges here are 22 kW. Pilot installations with power of 200 kW have already been realized. With regard to the range of action of the magnetic field lines, a distinction is drawn between so-called “short- range" and “mid-range" systems. In this case, a system having a ratio of the transfer distance to the coil dimension of less than 1 is allocated to the short- range systems, and systems having a ratio of greater than 1 are allocated to the mid-range systems. The two systems pursue different aims by virtue of the physical orientation to different theorems. The aim pursued by the mid-range system is that of power matching by impedance matching. The short-range system pursues the approach of maximizing efficiency.

DE 11 2018001 471 T5 discloses a transmitter coil of a charger for a vehicle having a receiver coil arranged at an upper end of a chassis of the vehicle. The coils are moved relative to each other and aligning such that the transmitter coil is disposed above and proximal to the receiver coil.

CN 105896 695 A discloses a suspension type wireless charging system of an electric bus platform. The suspension type wireless charging system comprises an electric energy emission coil and an electric energy receiving coil. The electric energy emission coil is arranged on the bus platform, the electric energy receiving coil is arranged on the electric bus. The charging system can be used for charging an ordinary structural electric bus in a wireless way driving to the bus platform. A safety air gap between the coils is established to ensure that the coils do not touch on uneven and bumpy road surfaces even at the highest position of the electric energy receiving coil. Disclosure of the invention

The object of the invention is to provide an improved apparatus for inductive charging of a high-voltage battery of a vehicle, which is usable in particular for commercial vehicles such as buses.

A further object is to specify an improved method for inductive charging of a high-voltage battery of a vehicle, which is usable in particular for commercial vehicles such as buses.

The objects are achieved by means of the features of the independent claims. Advantageous embodiments and advantages of the invention are evident from the further claims, the description and the drawing.

According to an aspect of the invention, an apparatus for inductive charging, in particular for inductive charging of a high-voltage battery of a vehicle, is proposed, comprising in each case at least: a DC/mid- frequency converter arranged at a charging infrastructure device, a mid-frequency/DC converter arranged in the vehicle, and a coil system comprising at least one first coil and at least one second coil, wherein the at least one first coil is arranged at the charging infrastructure device and the at least one second coil is arranged at the vehicle. The at least first one coil is electrically connected to the DC/m id-frequency converter and the at least one second coil is electrically connected to the mid-frequency/DC converter. The at least one first coil is arranged in a vertical axis above the vehicle and the at least one second coil is arranged on a roof of the vehicle. In this case, the at least one first coil and/or the at least one second coil are/is able to be brought together for charging purposes until the coils lie one on another in positively locking fashion. In particular, a minimum air gap can be established at the interface of the first and second coils. The minimal air gap of the coil system at the interface is determined by the distance which is required by a boundary and/or insulating layer between the coils. Favourably, the first and second coils may be arranged in a horizontal manner.

The proposed apparatus has advantages of inductive charging. On account of the transfer of electrical power without contact sets from a first coil as so- called primary coil to a second coil as so-called secondary coil, the apparatus is protected against wear and weather influences. The apparatus combines the advantages of charging by way of a pantograph with those of inductive charging and thus avoids the disadvantages of inductive charging such as health risks as a result of high magnetic field strengths and air gap clearances that can be reduced in size with difficulty or only in a costly way.

The coil system can also have a plurality of first coils and/or a plurality of second coils, depending on the geometric realization

The proposed inductive charging system is detached from the ground and is integrated into the pantograph instead of a mechanical contact set. In this case, the mechanical contact set of the pantograph is exchanged for the coil system of the inductive charging system.

The apparatus has two essential configurations. Either a movable part of the system, for example an arm, is situated on the vehicle, or the movable part of the system is situated in a manner suspended above the vehicle in the inverting sense. That is to say that one coil of the magnetic system is always arranged on the vehicle roof, while the other coil is suspended above the vehicle. One of the two coils is movable by means of a mechanical arm, for example. This configuration of the apparatus overcomes the disadvantages of inductive charging. The air gap of the coil system can easily be closed apart from a minimum required boundary and/or insulating layer between the coils. The coils lie one on another in positively locking fashion. Thus the magnetic fields can be guided considerably more precisely. That allows the magnetic emission and the stray fluxes of the system to be significantly reduced. It is thus possible to dispense with increased safety precautions since it is ensured that no living being is permeated by the high field strengths. Moreover, no foreign bodies can be situated between the coil systems. As a result of the primary coil and secondary coil being accurately positioned one on another and in close vicinity to each other at a minimal distance at the interface of the horizontally arranged coils, a corresponding gain in efficiency is possible. The efficiency of the inductive charging is considerably increased since the reactive power demand is considerably reduced according to the invention.

The proposed apparatus for inductive charging enables electrical power flows to be transferred into vehicles conveniently and safely, without manual action, i.e. in a manner initiated automatically.

In this case, provision can be made, in particular, for the primary coil and secondary coil to be able to be moved towards one another not just in a vertical direction. The charging infrastructure device can optionally move towards the vehicle to be charged in a horizontal direction as well. In particular, the device can also be configured to compensate for a tilt angle between the coils so that positively locking can be achieved between the coils. Freedom from barriers at future depots for commercial vehicles, which is intended to afford protection against possible damage to vehicles and devices, can largely be preserved since the system is constructed at height as intended.

The proposed apparatus provides a maximum degree of electrical safety. There are no charging implements such as charging cables which, given the required charging power, are difficult to mount by hand just on account of their size and their weight and which may threaten to be damaged by being run over or by being hit for example by snow clearing services. Contact sets subject to wear are not present. Weather influences are not a factor or can easily be monitored. The absence of electrical contacts ensures maximum protection against electric shock for personnel.

According to an advantageous embodiment of the apparatus, the charging infrastructure device can have an inverting pantograph, at which the at least first coil is arranged. In this way, when the vehicle stops beneath a charging point with the first coil, the first coil can be lowered onto the second coil by way of the inverting pantograph and the inductive charging process can thus be initiated when the two coils have reached a minimum distance when the coils lie one on another in a positively locking fashion with a minimal distance at the interface between the coils.

Alternatively or additionally, a pantograph can be arranged on the vehicle and the at least second coil can be arranged at the pantograph. In this way, when the vehicle stops beneath a charging point with the first coil, the second coil can be moved to the first coil by way of the pantograph and the inductive charging process can thus be initiated when the two coils have reached a minimum distance. The air gap of the coil system can easily be closed apart from the minimum distance which is required by a boundary and/or insulating layer between the coils. According to an advantageous embodiment of the apparatus, the at least first coil and the at least second coil can be configured in positively locking fashion. In particular, the at least first coil and the at least second coil can form a positively locking engagement in the brought-together state. If the two coils are configured such that they form a positively locking engagement at a minimum distance, advantageous conditions for the inductive energy transfer can be attained. Moreover, the fact that the position of the two coils relative to one another that is advantageous for the energy transfer has been reached can easily be detected in this way.

According to an advantageous embodiment, the apparatus can comprise a positioning device configured to position the at least first coil and/or the at least second coil in such a way that a minimum electrical reactive power is set during charging. A minimum distance between the two coils and a possible positively locking engagement can be set by means of the positioning device, which can be mechanically connected to one of the two coils. In particular, the positioning device can be configured to compensate for a tilt angle between the at least first and the at least second coil. This may be achieved by a rotation means provided by the positioning device, in particular by rotation means for two rectangular directions, which is able to effect a tilting angle of the at least first and the at least second coil. The efficiency of the energy transfer can thus advantageously be increased.

According to an advantageous embodiment of the apparatus, a control of the positioning device can be integrated in the DC/ mid-frequency converter or in the mid-frequency/DC converter.

In this way, the control of the positioning device can be implemented by way of a control of the reactive power of the system. The efficiency of the energy transfer can advantageously be increased as a result. According to an advantageous embodiment of the apparatus, the control can be coupled to an imaging optical system, which optically detects at least one position of the at least first coil or of the at least second coil. By this means, the control of the positioning device can be carried out in an advantageous manner and the two coils can be positioned at a minimum distance in an efficient manner.

The position of the two coils can thus be controlled more rapidly, particularly if the distance between the two coils is still relatively large.

Advantageously, the transferred electrical energy can be fed directly into the high-voltage battery from the mid-frequency/DC converter.

According to an advantageous embodiment of the apparatus, the mid- frequency/DC converter can be electrically connected to a DC/DC converter of a traction power converter. The transferred electrical energy can thus be fed into the DC-intermediate circuit of the traction power converter. In accordance with the stipulations of a battery control unit of the high-voltage battery, the DC/DC converter of the traction power converter then performs the closed-loop control of charging current and charging voltage, in a similar manner to that in the case of recuperation during travel.

According to an advantageous embodiment of the apparatus, the mid- frequency/DC converter can be configured as a passive diode bridge circuit.

In accordance with the arrangement that the transferred electrical energy is fed into the DC-intermediate circuit of the traction power converter, an active mid-frequency/DC converter is not needed, rather passive rectification of the mid-frequency is sufficient for fulfilling the objective. In this regard, the apparatus for inductive charging can be further simplified. Advantageously, the charging infrastructure device can have an AC/DC converter having a DC output, via which the DC/mid-frequency converter is electrically fed.

According to an advantageous embodiment of the apparatus, the charging infrastructure device can be electrically connected to a central DC supply.

In this embodiment, not every individual pantograph system has a dedicated AC/DC converter. Rather, a common AC/DC converter for all connected pantograph systems is installed at a central location and supplies all pantographs as a DC voltage source with the electrical energy for the charging process. Besides reducing costs for the overall system, cutting back and reducing the installations on mast arms and technical bridges of the charging infrastructure devices in the field is especially advantageous.

According to an advantageous embodiment of the apparatus, at least one of the at least first coil or the at least second coil can be actively cooled, in particular at least during the charging of the high-voltage battery. The heat loss that arises during the charging of the high-voltage battery can be advantageously dissipated as a result. If the two coils lie one on another in positively locking fashion during charging, then it is sufficient if only one of the two coils, the transmitter coil or the receiver coil, is actively cooled.

In this case, the respective other coil is concomitantly cooled by the heat transfer by means of heat conduction from the uncooled coil towards the cooled coil. According to a further aspect of the invention, a method for inductive charging, in particular for inductive charging of a high-voltage battery of a vehicle, is proposed, by means of an apparatus, comprising in each case at least one DC/m id-frequency converter arranged at a charging infrastructure device, one mid-frequency/DC converter arranged in the vehicle, one coil system, comprising at least one first coil and at least one second coil, wherein the at least first coil is arranged in a vertical axis above the vehicle and the at least second coil is arranged on a roof of the vehicle, wherein the at least first coil is electrically supplied by the DC/ mid-frequency converter and wherein the at least second coil is electrically connected to the mid- frequency/DC converter.

In this case, the method comprises at least the steps of driving the vehicle into a charging infrastructure device; bringing together the at least first and the at least second coils by moving the at least first coil towards the at least second coil and/or moving the at least second coil towards the at least first coil; starting the charging process.

The proposed method has advantages of inductive charging. On account of the transfer of electrical power without contact sets from a first coil as so- called primary coil to a second coil as so-called secondary coil, the method used is protected against wear and weather influences. The coils can be moved together until they lie one on another at their interface. The air gap between the primary and secondary coils can be minimized apart from a minimum distance which is required by a boundary and/or insulating layer between the coils. The method combines the advantages of conductive charging by way of a pantograph above the vehicle with those of inductive charging and thus avoids the disadvantages of inductive charging such as health risks as a result of high magnetic field strengths and air gap clearances that can be reduced in size with difficulty or only in a costly way.

In accordance with the proposed method, the inductive charging system is detached from the ground and is integrated into the pantograph instead of a mechanical contact set. In this case, the mechanical contact set of the pantograph is exchanged for the coil system of the inductive charging system.

The method has two essential configurations. Either a movable part of the system, for example an arm, is situated on the vehicle, or the movable part of the system is situated in a manner suspended above the vehicle in the inverting sense. That is to say that one coil of the magnetic system is always arranged on the vehicle roof, while the other coil is suspended above the vehicle. One of the two coils is movable by means of a mechanical arm, for example.

The proposed method overcomes the disadvantages of inductive charging. The air gap of the coil system can easily be closed apart from a minimum required boundary and/or insulating layer between the coils. The coils can lie one on another in positively locking fashion and the magnetic fields can be guided considerably more precisely. That allows the magnetic emission and the stray fluxes of the system to be significantly reduced. It is thus possible to dispense with increased safety precautions since it is ensured that no living being is permeated by the high field strengths. Moreover, no foreign bodies can be situated between the coil systems. As a result of the primary coil and secondary coil being accurately positioned one on another, a corresponding gain in efficiency is possible. The efficiency of inductive charging is considerably increased since the reactive power demand is considerably reduced according to the invention.

The proposed method for inductive charging enables electrical power flows to be transferred into vehicles conveniently and safely, without manual action, i.e. in a manner initiated automatically.

Freedom from barriers at future depots for commercial vehicles, which is intended to afford protection against possible damage to vehicles and devices, can largely be preserved since the system is constructed at height as intended.

The proposed method provides a maximum degree of electrical safety. There are no charging implements such as charging cables which, given the required charging power, are difficult to mount by hand just on account of their size and their weight and which may threaten to be damaged by being run over or by being hit for example by snow clearing services. Contact sets subject to wear are not present. Weather influences are not a factor or can easily be monitored.

The absence of electrical contacts ensures maximum protection against electric shock for personnel.

According to an advantageous embodiment of the method, the at least first coil can be lowered onto the at least second coil arranged in the vertical axis of the roof of the vehicle. In particular, the at least first coil can be lowered by means of an inverting pantograph arranged at the charging infrastructure device. In this way, when the vehicle stops beneath a charging point with the first coil, the first coil can be lowered onto the second coil by way of the inverting pantograph and the inductive charging process can thus be initiated when the two coils have reached a minimum distance. The air gap of the coil system can easily be minimized or closed apart from the minimum distance which is required by a boundary and/or insulating layer between the coils.

According to an advantageous embodiment of the method, the at least second coil arranged on a pantograph can be brought to the first coil arranged in the vertical axis above the vehicle, wherein the pantograph is arranged on the roof of the vehicle. In this way, when the vehicle stops beneath a charging point with the first coil, the second coil can be lowered onto the first coil by way of the pantograph and the inductive charging process can thus be initiated when the two coils have reached a minimum distance.

Advantageously, the first coil and the second coil can thus be brought together in positively locking fashion.

According to an advantageous embodiment of the method, the at least first coil and/or the at least second coil can be positioned by means of a positioning device in such a way that a minimum electrical reactive power is set during charging.

A minimum distance between the two coils and a possible positively locking engagement can be set by means of the positioning device, which can be mechanically connected to one of the two coils. In particular, the positioning device can be configured to compensate for a tilt angle between the at least first and the at least second coil. This may be achieved by a rotation means provided by the positioning device, in particular by rotation means for two rectangular directions, which is able to effect a tilting angle of the at least first and the at least second coil. The efficiency of the energy transfer can thus advantageously be increased. The air gap of the coil system can easily be closed or minimized apart from the minimum distance which is required by a boundary and/or insulating layer between the coils.

According to an advantageous embodiment of the method, the positioning device can be controlled by way of a control integrated in the DC/mid- frequency converter or in the mid-frequency/DC converter. In this way, the control of the positioning device can be implemented by way of a control of the reactive power of the system. The efficiency of the energy transfer can advantageously be increased as a result.

According to an advantageous embodiment of the method, at least one position of the at least first coil or of the at least second coil can be optically detected by means of an imaging optical system, and is transmitted to the control. By this means, the control of the positioning device can be carried out in an advantageous manner and the two coils can be positioned at a minimum distance in an efficient manner. The air gap of the coil system can easily be closed or at least minimized apart from the minimum distance which is required by a boundary and/or insulating layer between the coils. The position of the two coils can thus be controlled more rapidly, particularly if the distance between the two coils is still relatively large.

Advantageously, the electrical energy transferred via the mid-frequency/DC converter can be fed directly into the high-voltage battery. According to an advantageous embodiment of the method, the electrical energy can be transferred into a DC/DC converter of a traction power converter via the mid-frequency/DC converter. The transferred electrical energy can thus be fed into the DC-intermediate circuit of the traction power converter. In accordance with the stipulations of a battery control unit of the high-voltage battery, the DC/DC converter of the traction power converter then performs the closed-loop control of charging current and charging voltage, in a similar manner to that in the case of recuperation during travel.

According to an advantageous embodiment of the method, the electrical energy can be transferred via the mid-frequency/DC converter configured as a passive diode bridge circuit. If the transferred electrical energy is fed into the DC-intermediate circuit of the traction power converter, an active mid-frequency/DC converter is not needed, rather passive rectification of the mid-frequency is sufficient for fulfilling the objective. In this regard, the method for inductive charging can be further simplified.

Advantageously, the electrical energy in the charging infrastructure device can be fed into the DC/m id-frequency converter via an AC/DC converter having a DC output.

According to an advantageous embodiment of the method, the electrical energy can be fed into the charging infrastructure device from a central DC supply. In this configuration, not every individual pantograph system has a dedicated AC/DC converter. Rather, a common AC/DC converter for all connected pantograph systems is installed at a central location and supplies all pantographs as a DC voltage source with the electrical energy for the charging process. Besides reducing costs for the overall system, cutting back and reducing the installations on mast arms and technical bridges of the charging infrastructure devices in the field is especially advantageous. According to an advantageous embodiment of the apparatus, at least one of the at least first coil or the at least second coil can be actively cooled, in particular at least during the charging of the high-voltage battery. The heat loss that arises during the charging of the high-voltage battery can be advantageously dissipated as a result.

If the two coils lie one on another in positively locking fashion during charging at minimum distance, then it is sufficient if only one of the two coils, the transmitter (primary) coil or the receiver (secondary) coil, is actively cooled. In this case, the respective other coil is concomitantly cooled by the heat transfer by means of heat conduction from the uncooled coil towards the cooled coil.

According to a further aspect of the invention, a charging station is proposed for performing a charging process of vehicles by means of an apparatus for inductive charging of a high-voltage battery of the vehicles. The charging station comprises at least one mount, in which at least one charging infrastructure device is arranged in displaceable fashion, an AC/DC converter for the electrical supply of the charging infrastructure device, and a positioning aid device for wireless communication at least with a vehicle. The charging infrastructure device is positionable in a vertical axis above a vehicle stopping underneath. The positioning aid device is configured to allocate a stop position to the vehicle.

The positioning aid device can direct the charging infrastructure device to the stop position of the vehicle. In this case, in particular lateral movements of the charging infrastructure device along the mount are possible. However, a movement of the charging infrastructure device perpendicularly to the lateral movement direction is also conceivable, such that not only vehicles standing next to one another but also vehicles standing one behind another can be charged. Advantageously, a communication technology present in the vehicle anyway can be utilized. An accurate positioning can be effected independently of the type of vehicle, since the sensor system refers to the position of the “coils in space” and not to the vehicle geometry. Displays and aids outside the vehicle can therefore be omitted.

Advantageously, in this way the charging infrastructure device can intelligently approach the vehicle to be charged. Manoeuvring of the vehicle can be obviated. Charging management can be effected with full automation. Charging can be performed conveniently and safely for the user.

According to an advantageous embodiment of the charging station, the positioning aid device can be configured for wireless communication with at least one telematics control centre.

In commercial vehicles, telematics is nowadays a standard instrument for communication between driver and depot. Technical vehicle data and job- related data are exchanged by that means.

Drawings

Further advantages will become apparent from the following description of the drawing. Exemplary embodiments of the invention are illustrated in the figures. The figures, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form practical further combinations. In the figures, by way of example:

Fig. 1 shows a charging process of a vehicle by means of an apparatus for inductive charging of a high-voltage battery of the vehicle, in particular of a commercial vehicle such as a bus, with an inverting pantograph according to one exemplary embodiment of the invention;

Fig. 2 shows a charging process of a vehicle by means of an apparatus for inductive charging of a high-voltage battery of the vehicle, in particular of a commercial vehicle such as a bus, with a pantograph according to a further exemplary embodiment of the invention;

Fig. 3 shows a schematic block diagram of the electrical components of the apparatus for inductive charging with a positioning device for aligning the first coil according to a further exemplary embodiment of the invention;

Fig. 4 shows a schematic block diagram of the electrical components of the apparatus for inductive charging with a positioning device for aligning the second coil according to a further exemplary embodiment of the invention;

Fig. 5 shows a charging process of a vehicle by means of an apparatus for inductive charging according to a further exemplary embodiment of the invention, wherein the transferred electrical energy is fed directly into the high-voltage battery; Fig. 6 shows a charging process of a vehicle by means of an apparatus for inductive charging according to a further exemplary embodiment of the invention, wherein the transferred electrical energy is fed into a traction power converter;

Fig. 7 shows a charging process of a vehicle by means of an apparatus for inductive charging according to a further exemplary embodiment of the invention, wherein the transferred electrical energy is fed into a traction power converter via a passive diode bridge circuit as mid-frequency/DC converter; and

Fig. 8 shows a charging process of a vehicle by means of an apparatus for inductive charging according to a further exemplary embodiment of the invention, wherein the charging infrastructure device is fed via a central DC supply;

Fig. 9 shows a charging station for performing a charging process of vehicles by means of an apparatus for inductive charging of a high-voltage battery of the vehicle, in particular of a commercial vehicle such as a bus, with an inverting pantograph according to one exemplary embodiment of the invention; and

Fig. 10 shows a flow diagram of a method for inductive charging, in particular for inductive charging of a high-voltage battery of a vehicle, according to one exemplary embodiment of the invention. Embodiments of the invention

In the figures, components of identical type or components that act identically are designated by identical reference numerals. The figures merely show examples and should not be understood as limiting.

Direction terminology used hereinafter with terms such as “left”, “right”, “top”, “bottom”, “in front”, “behind”, “after” and the like serves merely for the better understanding of the figures and on no account is it intended to represent a restriction of the generality. The presented components and elements, by design and use may vary within the considerations of a person skilled in the art and may be adapted to the respective applications.

Figure 1 shows a charging process of a vehicle 110 by means of an apparatus 100 for inductive charging of a high-voltage battery 20 of the vehicle 110, in particular of a commercial vehicle such as a bus, with an inverting pantograph 52 according to one exemplary embodiment of the invention. Figures 3 and 4 each illustrate in this respect a schematic block diagram of the electrical components of the apparatus 100 for inductive charging.

The apparatus 100 comprises in each case at least one DC/m id-frequency converter 12 arranged at a charging infrastructure device 50, one mid- frequency/DC converter 18 arranged in the vehicle 110, and one coil system comprising at least one first coil 14 and at least one second coil 16, wherein the at least first coil 14 is arranged at the charging infrastructure device 50 and the at least second coil 16 is arranged at the vehicle 110. The at least first coil 14 is electrically connected to the DC/mid-frequency converter 12 and the at least second coil 16 is electrically connected to the mid- frequency/DC converter 18. The at least first coil 14 is arranged in a vertical axis 112 above the vehicle 110, and the at least second coil 16 is arranged on a roof 114 of the vehicle 110. In this case, the at least first coil 14 and/or the at least second coil 16 are able to be brought together for charging purposes.

In particular, the first coil 14 and the second coil 16 are arranged in a horizontal manner.

The at least first coil 14 and the at least second coil 16 are configured in positively locking fashion. In particular, the two coils 14, 16 form a positively locking engagement in the brought-together state. The air gap between the two coils 14, 16 can easily be minimized or closed apart from a minimal distance at the interface which is required by a boundary and/or insulating layer between the coils 14, 16.

In Figure 1 , the vehicle 110 in the form of a bus has been parked beneath an inverting inductive pantograph 52. The inverting pantograph 52 is suspended for example on a mast arm or beneath a technical bridge 54 of a charging infrastructure device 50. The charging infrastructure device 50 can be arranged for example on a ceiling 56 of an operations hall. A first coil 14 of a coil system is situated at the lower end of the movable part of the pantograph 52. A second coil 16 of the coil system is mounted on the vehicle roof 114. The associated electronic components for the operation of the first coil 14 can be fitted or accommodated in weather-resistant housings on the technical bridge 54 or a mast arm. The movable part of the pantograph 52 is illustrated schematically as a scissor system. However, this part can also be implemented by other solutions according to the prior art, such as e.g. as an articulated arm or as a linear guide. The movable part is essentially provided for freedom of movement in the vertical axis 112 in the form of an upwards and downwards movement. Additionally, a joint can be provided in the movable part to adjust a mutual position of the two coils 14, 16 in case one of the coils 14, 16, in particular the second coil 16 is tilted with respect to the other one.

The apparatus 100 can have for this purpose a positioning device 22 configured to position the at least first coil 14 and/or the at least second coil 16 in such a way that a minimum electrical reactive power is set during charging. A control of the positioning device 22 can be integrated in the DC/m id-frequency converter 12 or in the mid-frequency/DC converter 18.

Alternatively or additionally, the control can be coupled to an imaging optical system, which optically detects at least one position of the at least first coil 14 or of the at least second coil 16 and thereby enables the first and second coils 14, 16 to be brought together directly and efficiently until the minimal distance required by insulation layers or boundary layers is reached and contact is made at the interface between the coils 14, 16.

Preferably, in the case of an apparatus 100 having an inverting pantograph 52, the positioning device 22 will be integrated into the inverting pantograph 52 or formed by the latter, such that in this case the first coil 14 can be brought towards the second coil 16 or can be guided for tracking movements of the vehicle 110. Advantageously, it is thus possible to automatically compensate for the movement latitude (tolerance space) of the coil system owing to the lowering of the chassis on one side (so-called “kneeling”) or spring play when the chassis is subjected to loading and relief of loading, as occurs precisely during the operation of buses in order to facilitate access or alighting and boarding of passengers. In particular, a tilt angle between the coils 14, 16 can also be compensated.

Figure 2 shows a charging process of a vehicle 110 by means of an apparatus 100 for inductive charging of a high-voltage battery 20 of the vehicle 110, in particular of a commercial vehicle such as a bus, with a pantograph 116 according to a further exemplary embodiment of the invention.

The pantograph 116 is configured as a standard pantograph. In this case, the movable part of the pantograph 116 with the second coil 16 of the coil system is mounted on the vehicle roof 114. The positionally fixed part, i.e. the first coil 14 of the coil system, is mounted in stationary fashion above the vehicle 110. This apparatus operates functionally in the same way as in the exemplary embodiment according to Figure 1 .

The difference is that when the system is quiescent, the movable part is lowered onto the vehicle roof 114, whereas in the exemplary embodiment in Figure 1 the movable part is raised under the technical support 54 in the quiescent position. The movable part of the pantograph 116 can likewise be implemented according to a variety of prior art, as described above. Preferably, in the case of this apparatus 100 having a standard pantograph 116, the positioning device 22 will be integrated into the pantograph 116 or formed by the latter, such that in this case the second coil 16 can be brought towards the first coil 14 or can be guided for tracking movements of the vehicle 110.

Figure 3 shows a schematic block diagram of the electrical components of the apparatus 100 for inductive charging with a positioning device 22 for aligning the first coil 14 according to a further exemplary embodiment of the invention. Figure 4 illustrates an exemplary embodiment in which the positioning device 22 is used for aligning the second coil 16.

An AC/DC converter 10 is connected to an AC electrical grid (not illustrated) and obtains therefrom the energy for the apparatus 100 for inductive charging. That is done according to the prior art very generally in a manner beneficial to the grid and supporting the grid. That is to say that the electric currents accepted are sinusoidal with very low harmonic content and, as necessary, the AC/DC converter 10 can also provide reactive power for grid support. The AC/DC converter 10 can be implemented technologically as active low-pass filter and buck converter or as boost inverter and boost converter. The AC/DC converter 10 yields a DC voltage at its output and thereby provides a supply for the DC/m id-frequency converter 12.

The DC/m id-frequency converter 12 generates a voltage in the kilohertz range, the first coil 14 of the coil system being supplied thereby. The magnetic coupling of the two coils 14, 16 is indicated by magnetic field lines 70 in Figures 3 and 4. Since the coupled first and second coils 14, 16 are not wound on a common core for magnetic flux concentration, the coil system is expediently implemented with a large area in order thus to minimize the magnetic stray fluxes, i.e. those which couple alongside the windings. That has a direct influence on the reactive power required for the system. The lower the stray fluxes and the shorter the distance between the two coils 1 , 16, the better the efficiency of the overall system becomes. Therefore, it is advantageous for a large-area second coil 16 to be arranged on a large-area commercial vehicle roof 114 and to be coupled to a first coil 14 closely and at a very small distance during the charging process. The air gap between the two coils 14, 16 can easily be minimized or closed apart from the minimum distance which is required by a boundary and/or insulating layer between the coils 14, 16.

The mid-frequency/DC converter 18 arranged at the vehicle conditions the voltage and the current from the second coil in the manner of required by the battery management system (BMS) of the vehicle 110, or of the high- voltage battery 20, i.e. provides the charging power for the high-voltage battery 20.

The apparatus 100 furthermore has an intelligent positioning device 22. The positioning device 22 serves to move the first coil 14 (Figure 3) or the second coil 16 (Figure 4) in three axes. In particular, the positioning device 22 can be configured to compensate for a tilt angle between the at least first and the at least second coil 14, 16. This may be achieved by a rotation means provided by the positioning device 22, in particular by rotation means for two rectangular directions, which is able to effect a tilting angle of the at least first and the at least second coil 14, 16. The positioning system 22 can be controlled either from the DC/mid- frequency converter 12 or from the mid-frequency/DC converter 18. The control positions the first and/or second coil 14, 16 - movable in the axes - of the control system in such a way that the reactive power of the system is minimal. This is the case if the two coils 14, 16 lie one on another in positively locking fashion and are separated from one another only by their insulating layers, which are simultaneously the housing walls.

The control operates during the entire charging process and therefore also compensates for movements of the vehicle 110 that originate from the spring suspension of the chassis in height, tilt angle and lateral position.

Figure s shows a charging process of a vehicle 110 by means of an apparatus 100 for inductive charging according to a further exemplary embodiment of the invention, wherein the transferred electrical energy is fed directly into the high-voltage battery 20.

The AC/DC converter 10 and the DC/m id-frequency converter 12 are situated outside the vehicle 110 and can be accommodated flexibly and at different locations, being able to be located either on the technical bridge 54 or on a mast arm itself or else in housings outside and placed on the ground. The mid-frequency/DC converter 18 is integrated in the vehicle and feeds a charging current into the high-voltage battery 20. The second coil 16 of the coil system is arranged on the vehicle roof 114 and the first coil 14 is arranged above the vehicle. A pantograph possibly present has been omitted in Figure 5 for the sake of clarity. In this case, the second coil 16 can either be arranged on the roof 114, be partly integrated or be wholly integrated into the roof 114. The charging process is normatively controlled by the charging controller SECC (Supply Equipment Communication Control) and EVCC (Electrical Vehicle Communication Control), which in turn communicate with an equipment manager 32. In general and according to the prior art, the traction power converter 24 consists of two functional units: a DC/AC converter 26 for the adaptation of the drive 30 and a DC/DC converter 28. The DC/AC converter 26 supplies the drive 30 with sinusoidal currents with low harmonic content during driving operation.

During braking operation (recuperation mode), the generator currents are kept sinusoidal on the machine side and are fed as DC currents on the output side into the DC-intermediate circuit of the traction power converter 24. During driving operation, the DC/DC converter 28 supplies the DC/AC converter 26 with DC voltage and current in such a way that the efficiency of the overall system is maximal. In the recuperation mode, the DC/DC converter 28 adapts the electrical variables according to stipulations of the battery management system (BMS).

Figure 6 shows a charging process of a vehicle 110 by means of an apparatus 100 for inductive charging according to a further exemplary embodiment of the invention, wherein the transferred electrical energy is fed into a traction power converter 24. In Figure 7, the transferred electrical energy is in this case fed into the traction power converter 24 via a passive diode bridge circuit as mid-frequency/DC converter 18. In this exemplary embodiment, the electrical energy fed via the two coils 14, 16 of the coil system is not fed directly into the high-voltage battery 20, but rather into the DC-intermediate circuit of the traction power converter 24. For this purpose, the mid-frequency/DC converter 18 is electrically connected to a DC/DC converter 28 of the traction power converter 24. The DC/DC converter 28 of the traction power converter 24 then performs the closed-loop control of charging current and voltage in accordance with the stipulations of the PMS system, in a similar manner to that in the case of recuperation during travel.

In accordance with this arrangement, there is no need for an active mid- frequency/DC converter 18. Rather, passive rectification of the midfrequency is sufficient for fulfilling the object, as is illustrated in the exemplary embodiment in Figure 7.

In this case, the mid-frequency/DC converter 18 is configured as a passive diode bridge circuit. This is possible provided that bidirectional energy transport between vehicle 110 and charging infrastructure device 50 is not demanded. The apparatus 100 can thus be simplified again by this configuration.

Figure s shows a charging process of a vehicle 110 by means of an apparatus 100 for inductive charging according to a further exemplary embodiment of the invention, wherein the charging infrastructure device 50 is supplied via a central DC supply 60. In this configuration, not every individual charging infrastructure device 50 obtains a dedicated AC/DC converter 10, but rather a common AC/DC converter 10 of the central DC supply 60 for all connected charging infrastructure devices 50 is installed at a central location and supplies charging infrastructure devices 50 as a DC voltage source with the electrical energy for the charging process. Besides reducing costs for the overall system, cutting back and reducing the installations on mast arms and technical bridges in the field is especially advantageous.

Advantageously, at least one of the at least first coil 14 or the at least second coil 16 can be actively cooled, in particular at least during the charging of the high-voltage battery 20. As a result, the heat loss that arises during the charging of the high-voltage battery 20 can be advantageously dissipated. If the two coils 14, 16 lie one on another in positively locking fashion during charging, then it is sufficient if only one of the two coils 14, 16, the transmitter coil or the receiver coil, is actively cooled. In this case, the respective other coil 14, 16 is concomitantly cooled by the heat transfer by means of heat conduction from the uncooled coil towards the cooled coil 14, 16.

Figure 9 shows a charging station 1000 for performing a charging process on vehicles 110 by means of an apparatus 50 for inductive charging of a high-voltage battery 20 of a vehicle 110, in particular of a commercial vehicle such as a bus, with an inverting pantograph according to one exemplary embodiment of the invention.

The charging station 1000 has a mount 1100, in which at least one charging infrastructure device 50 is arranged in laterally displaceable fashion. A common AC/DC converter 10 serves for the electrical supply of the charging infrastructure device 50 via a DC/m id-frequency converter 12. In the example, two inverted pantographs as charging infrastructure device 50 are arranged in laterally displaceable fashion along a bridge-like mount 1100. A charging infrastructure device 50 can thus be positioned in a targeted manner in a vertical axis 112 above a vehicle 110 stopping underneath.

A positioning aid device 1200 for wireless communication can communicate with a vehicle 110 via a telematics control centre 1300, for example, which is connected to the telematics equipment present in said vehicle, and can allocate a stop position to the vehicle 110. However, the positioning aid device 1200 can also communicate with the vehicle 110 directly, without contact with a telematics control centre 1300.

Furthermore, the positioning aid device 1200 can direct the charging infrastructure device 50 to the stop position of the vehicle 110.

In the example shown, only a lateral movement of the charging infrastructure device 50 along the mount 1100 takes place. However, a movement of the charging infrastructure device 50 perpendicularly to the lateral movement direction is also conceivable, such that not only vehicles standing next to one another but also vehicles standing one behind another 110 can be charged. Advantageously, a communication technology present anyway can be utilized. An accurate positioning can be effected independently of the type of vehicle, since the sensor system refers to the position of the “coils in space” and not to the vehicle geometry. Displays and aids outside the vehicle 110 can therefore be omitted.

Advantageously, the charging infrastructure device 50 can intelligently approach the vehicle 110 to be charged. Manoeuvring of the vehicle 110 can be obviated. Charging management can be effected with full automation. Charging can be performed conveniently and safely for the user.

Figure 10 shows a flow diagram of a method for inductive charging, in particular for inductive charging of a high-voltage battery 20 of a vehicle 110, according to one exemplary embodiment of the invention.

The method is preferably carried out by an apparatus 100, as illustrated in Figures 1 to 9, comprising in each case at least one DC/m id-frequency converter 12 arranged at a charging infrastructure device 50, one mid- frequency/DC converter 18 arranged in the vehicle 110, and one coil system comprising at least one first coil 14 and at least one second coil 16, wherein the at least first coil 14 is arranged in a vertical axis 112 above the vehicle 110 and the at least second coil 16 is arranged on a roof 114 of the vehicle 110.

The at least first coil 14 is electrically supplied by the DC/m id-frequency converter 12 and the at least second coil 16 is electrically connected to the mid-frequency/DC converter 18. In step S100 of the method, the vehicle 110 is driven into a charging infrastructure device 50. In step S102, the at least first and the at least second coils 14, 16 are brought together by moving the at least first coil 14 towards the at least second coil 16 and/or by moving the at least second coil 16 towards the at least first coil 14. Afterwards, the charging process can be started in step S104.

The at least first coil 14 can be lowered onto the at least second coil 16 arranged in the vertical axis 112 on the roof 114 of the vehicle 110. In particular, the at least first coil 14 can be lowered by means of an inverting pantograph 52 arranged at the charging infrastructure device 50.

Alternatively or additionally, the at least second coil 16 arranged on a pantograph 116 can be brought to the first coil 14 arranged in the vertical axis 112 above the vehicle 110, wherein the pantograph 116 is arranged on the roof 114 of the vehicle 110.

The at least first coil 14 and/or the at least second coil 16 can be positioned by means of a positioning device 22 in such a way that a minimum electrical reactive power is set during charging. For this purpose, the positioning device 22 can be controlled by way of a control integrated in the DC/mid- frequency converter 12 or in the mid-frequency/DC converter 18.

Alternatively or additionally, at least one position of the at least first coil 14 or of the at least second coil 16 can be optically detected by means of an imaging optical system, and is transmitted to the control.

The electrical energy transferred can be fed directly into the high-voltage battery 20 via the mid-frequency/DC converter 18. Alternatively, it is also possible for the electrical energy to be transferred into a DC/DC converter 28 of a traction power converter 24 via the mid- frequency/DC converter 18.

In a further embodiment, the electrical energy can be transferred via the mid-frequency/DC converter 18 configured as a passive diode bridge circuit, which further simplifies the apparatus 100. The electrical energy required for charging can be obtained from a supply grid via a dedicated AC/DC converter 10 of the charging infrastructure device 50 and can be converted into a DC voltage by the AC/DC converter 10. Alternatively, however, it is also possible for the electrical energy to be fed into the charging infrastructure device 50 from a central DC supply 60, such that no dedicated AC/DC converter 10 is required in the charging infrastructure device 50.

Reference numerals

10 AC/DC converter

12 DC/ mid-frequency converter

14 First coil

16 Second coil

18 mid-frequency/DC converter

20 High-voltage battery

22 Positioning device

24 T raction power converter

26 DC/AC converter

28 DC/DC converter

30 Drive

32 Equipment manager

34 SECC

36 EVCC

50 Charging infrastructure device

52 Inverting pantograph

54 Technical support

56 Ceiling

60 DC supply

70 Magnetic field lines

100 Apparatus

110 Vehicle

112 Vertical axis

114 Vehicle roof

116 Pantograph

1000 Charging station

1100 Mount

1200 Positioning aid device

1300 Telematics control centre

Claims

1. Apparatus (100) for inductive charging, in particular for inductive charging of a high-voltage battery (20) of a vehicle (110), comprising in each case at least

- a DC/m id-frequency converter (12) arranged at a charging infrastructure device (50),

- a mid-frequency/DC converter (18) arranged in the vehicle (110),

- a coil system, comprising at least one first coil (14) and at least one second coil (16), wherein the at least one first coil (14) is arranged at the charging infrastructure device (50) and the at least one second coil (16) is arranged at the vehicle (110), wherein the at least one first coil (14) is electrically connected to the DC/m id-frequency converter (12) and wherein the at least one second coil (16) is electrically connected to the mid-frequency/DC converter (18), wherein the at least one first coil (14) is arranged in a vertical axis (112) above the vehicle (110), and wherein the at least second coil (16) is arranged on a roof (114) of the vehicle (110), and wherein the at least first coil (14) and/or the at least second coil (16) are able to be brought together for charging purposes until the coils (14, 16) lie one on another in positively locking fashion.

2. Apparatus according to Claim 1 , wherein the charging infrastructure device (50) has an inverting pantograph (52), at which the at least first coil (14) is arranged, and/or wherein a pantograph (116) is arranged on the vehicle (110) and the at least second coil (16) is arranged at the pantograph (116). Apparatus according to Claim 1 or 2, wherein the at least first coil (14) and the at least second coil (16) are configured in positively locking fashion, in particular form a positively locking engagement in the brought-together state. Apparatus according to any of the preceding claims, comprising a positioning device (22) configured to position the at least first coil (14) and/or the at least second coil (16) in such a way that a minimum electrical reactive power is set during charging. Apparatus according to Claim 4, wherein a control of the positioning device (22) is integrated in the DC/mid-frequency converter (12) or in the mid-frequency/DC converter (18). Apparatus according to Claim 5, wherein the control is coupled to an imaging optical system, which optically detects at least one position of the at least first coil (14) or of the at least second coil (16). Apparatus according to any of the preceding claims, wherein the mid- frequency/DC converter (18) is electrically connected to a DC/DC converter (28) of a traction power converter (24). Apparatus according to Claim 7, wherein the mid-frequency/DC converter (18) is configured as a passive diode bridge circuit. Apparatus according to any of the preceding claims, wherein the charging infrastructure device (50) is electrically connected to a mid-DC supply (60). Apparatus according to any of the preceding claims, wherein at least one of the at least first coil (14) or the at least second coil (16) is actively cooled, in particular at least during the charging of the high-voltage battery (20). Method for inductive charging, in particular for inductive charging of a high-voltage battery (20) of a vehicle (110), by means of an apparatus (100) according to any of the preceding claims, comprising in each case at least

- one DC/m id-frequency converter (12) arranged at a charging infrastructure device (50),

- one mid-frequency/DC converter (18) arranged in the vehicle (110),

- one coil system, comprising at least one first coil (14) and at least one second coil (16), wherein the at least first coil (14) is arranged in a vertical axis (112) above the vehicle (110) and the at least second coil (16) is arranged on a roof (114) of the vehicle (110), wherein the at least first coil (14) is electrically supplied by the DC/mid- frequency converter (12) and wherein the at least second coil (16) is electrically connected to the mid-frequency/DC converter (18), wherein the method comprises at least the steps of

- driving the vehicle (110) into a charging infrastructure device (50);

- bringing together the at least first and the at least second coils (14, 16) by moving the at least first coil (14) towards the at least second coil (16) and/or moving the at least second coil (16) towards the at least first coil (14) until the coils (14, 16) lie one on another in positively locking fashion;

- starting the charging process. Method according to Claim 11 , wherein the at least first coil (14) is lowered onto the at least second coil (16) arranged in the vertical axis (112) on the roof (114) of the vehicle (110), in particular is lowered by means of an inverting pantograph (52) arranged at the charging infrastructure device (50). Method according to Claim 11 or 12, wherein the at least second coil (16) arranged on a pantograph (116) is brought to the first coil (14) arranged in the vertical axis (112) above the vehicle (110), wherein the pantograph (116) is arranged on the roof (114) of the vehicle (110). Method according to any of Claims 11 to 13, wherein the at least first coil (14) and/or the at least second coil (16) are positioned by means of a positioning device (22) in such a way that a minimum electrical reactive power is set during charging. Method according to Claim 14, wherein the positioning device (22) is controlled by way of a control integrated in the DC/m id-frequency converter (12) or in the mid-frequency/DC converter (18). Method according to Claim 15, wherein at least one position of the at least first coil (14) or of the at least second coil (16) is optically detected by means of an imaging optical system, and is transmitted to the control. Method according to any of Claims 11 to 16, wherein the electrical energy is transferred into a DC/DC converter (28) of a traction power converter (24) via the mid-frequency/DC converter (18). Method according to Claim 17, wherein the electrical energy is transferred via the mid-frequency/DC converter (18) configured as a passive diode bridge circuit. Method according to any of Claims 11 to 18, wherein the electrical energy is fed into the charging infrastructure device (50) from a central DC supply (60). Method according to any of Claims 11 to 19, wherein at least one of the at least first coil (14) or the at least second coil (16) is actively cooled, in particular at least during the charging of the high-voltage battery (20). Charging station (1000) for performing a charging process of vehicles (110) by means of an apparatus (100) for the inductive charging of a high-voltage battery (20) of the vehicles (110) according to any one of the claims 1 to 10, at least comprising

- a mount (1100), in which at least one charging infrastructure device (50) is arranged in displaceable fashion,

- an AC/DC converter (10) for the electrical supply of the charging infrastructure device (50),

- a positioning aid device (1200) for wireless communication at least with a vehicle (110), wherein the charging infrastructure device (50) is positionable in a vertical axis (112) above a vehicle (110) stopping underneath, wherein the positioning aid device (1200) is configured to allocate a stop position to the vehicle (110). Charging station according to Claim 21 , wherein the positioning aid device (1200) is configured for wireless communication with at least one telematics control centre (1300).