WO2019157623A1

WO2019157623A1 - Hybrid charging system

Info

Publication number: WO2019157623A1
Application number: PCT/CN2018/076621
Authority: WO
Inventors: Kai TIAN; Tinho LI; Kuenfaat YUEN
Original assignee: Abb Schweiz Ag
Priority date: 2018-02-13
Filing date: 2018-02-13
Publication date: 2019-08-22

Abstract

A hybrid charging system (12) for electric vehicles (14, 15) comprises an power converter (42) connectable to an electric AC grid (18); a transformer (44) connected with the power converter (42) with a primary winding (60); a secondary side AC-to-DC converter (46) connected with a secondary winding (62) of the transformer (44) and for providing a DC current for power transfer to an electric vehicle (15) via a cable (40); and a first inductive coil (24) connected in series with the primary winding (60) of the transformer (44) and for inductively coupling to a second inductive coil (28) for power transfer to an electric vehicle (14) via an air gap.

Description

HYBRID CHARGING SYSTEM

Technical Field

The invention relates to the field of electric vehicles. In particular, the invention relates to a hybrid charging system for electric vehicles and to a charging system arrangement.

Background Art

Electric vehicles may be charged via wired or wireless power transfer. Wireless power transfer via two inductively coupled coils, which form an air transformer, is in direct competition with wired power transfer that in the moment seems to be more reliable and cost effective. However, in the recent years, for wireless power transfer, the transfer distance at kilowatts power level increased from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. These advances make wireless power transfer very attractive to charging of electric vehicles in both stationary and dynamic charging scenarios.

Even though in terms of functionality the two types of charging system are intrinsically different, they have some commonalities. Both types may comprise a two stage topology comprising an AC-to-DC converter and a DC-to-DC converter with an internal transformer. In the case of the wired topology, the transformer is part of the charging system, while in the wireless topology, the transformer is provided by the two inductively coupled coils. Thus, in the wireless case, the DC-to-DC converter is distributed between the charging system and the electric car to be charged.

WO 2016 019 463 A1 describes a charger capable of working work with wireless and wired charging technologies. However, no specific topologies are disclosed.

Brief Summary of the Invention

It is an objective of the invention to provide a simple and economic charging system providing wired and wireless charging capability.

This objective is achieved by the subject-matter of the independent claims. Further exemplary embodiments are evident from the dependent claims and the following description.

An aspect of the invention relates to a hybrid charging system for electric vehicles. In this context, the term “hybrid” may refer to a charging system that is adapted for charging with the wired and wireless power transfer. An electric vehicle may be a street vehicle that may be driven with an electric motor, which is supplied by a battery. The hybrid charging system may be used for charging the battery. Also a hybrid vehicle, i.e. a vehicle with a combustion engine and an electrical motor, may be seen as an electric vehicle.

According to an embodiment of the invention, the hybrid charging system comprises a power converter connectable to a power source for converting the power from the power source into AC power output; a transformer connected with the power converter with a primary winding; a secondary side AC-to-DC converter connected with a secondary winding of the transformer and for providing a DC current for power transfer to an electric vehicle via a cable; and a first inductive coil connected in series with the primary winding of the transformer and for inductively coupling to a second inductive coil for power transfer to an electric vehicle via an air gap.

The hybrid charging system may be seen as a multi-mode charging system capable of delivering power through wired and wireless power transfer.

The hybrid charging system may share components that are used for wired and wireless charging. One power converter, which may comprise an AC-to-DC converter and a DC-to-AC converter, may be connected with both the transformer and the first inductive coil. The DC-to-AC converter, the transformer and the secondary side AC-to-DC converter may be seen as a first DC-to-DC converter for wired charging. The DC-to-AC converter, the inductively coupled first and second coils and an AC-to-DC converter provided in an electric vehicle may be seen as a second DC-to-DC converter for wireless charging via the air transformer formed by the inductively coupled first and second coils.

It has to be noted that the first and second DC-to-DC converters, which share their primary side converter, both are galvanic separated converters. The galvanic separation for the wired topology part may be a highly coupled transformer.

Both DC-to-DC converters may have a primary side DC-to-AC converter, which may be adapted to generate a square voltage waveform on the primary side of the respective transformer.

The transformer for the wired topology part of the charging system may comprise a primary and a secondary winding that are inductively coupled via a common core. The AC-to-DC converter connected to the secondary winding may be connected with an electric vehicle via a cable. For example, the electric vehicle has a plug for such a cable, which then can directly charge a battery of the electric vehicle.

The galvanic separation for the wireless topology part may be a loosely coupled air transformer. Both first and second inductive coils may be flat coils that may be arranged substantially parallel with each other. For example, the first coil may be provided in a ground adapter below the electric vehicle, which has the second inductive coil in its underbody. With such an air transformer, energy may be transmitted across distances of several decimeter. A magnetic field that changes with time is generated with the first inductive coil. Part of the magnetic field flows through the second inductive coil and induces a current flow. The second inductive coil may be connected via a rectifier with the battery of the electric car, which then may be charged.

According to an embodiment of the invention, the hybrid charging system further comprises a first switch connected across the primary winding of the transformer for bypassing power transfer to the primary winding of the transformer from the AC-to-AC-converter and a second switch connected across the first inductive coil for bypassing power transfer to the first inductive coil from the AC-to-AC-converter.

According to an embodiment of the invention, the first switch is a normally open switch and the second switch is a normally closed switch. It may be that the hybrid charging system is normally in a wired charging mode. When an electric vehicle is connected to the charging cable, it can be charged without the necessity of detecting a demand for charging. A normally closed switch may be a switch that is closed, when no control signal is applied. A normally open switch may be a switch that is open, when no control signal is applied. Both switches may be mechanical switches.

On the other hand, when a controller receives a request for wireless charging, for example from a sensor that detects an electric vehicle or its second inductive coil near the first inductive coil, both switches may be switched and the electric vehicle may be charged via the first inductive coil.

It also may be that the electric vehicle is adapted to be charged by both types of topologies. In the case, there is a defect or problem with the wireless charging part of the hybrid charging system, the normally closed first switch and the normally open second switch provide the ability to charge the electric vehicle via the wire bound charging part.

According to an embodiment of the invention, the hybrid charging system further comprises a controller for opening and closing the first switch and the second switch, such that solely the transformer or solely the first inductive coil is fed with power transferred from the power converter. The switches may be controlled by a controller that also may be responsible for controlling the semiconductor switches of the hybrid charging system. In particular, the semiconductor switches of the power converter.

When the first switch is a normally closed switch and the second switch is a normally open switch, only one control signal may be applied to both switches by the controller.

According to an embodiment of the invention, the controller is adapted for receiving a wireless communication signal indicating a charging type of an electric vehicle. For example, the controller may be connected to a wireless receiver, for example a WLAN receiver. The electric vehicle to be charged may send a charging signal with the respective charging type to the wireless receiver.

The controller may be adapted for opening and closing the first switch and the second switch according to the received charging type. I. e. when the charging type is “wired” , then the switches may be switched, such that the power is fed to the primary winding of the transformer transferred from the power converter and such that the first inductive coil is short-circuited from the power converter. When the charging type is “wireless” , then the switches may be switched, such that the primary winding of the transformer is short-circuited from the power converter and such that the first inductive coil is fed with the power transferred from the power converter.

According to an embodiment of the invention, the hybrid charging system further comprises a wireless receiver for receiving a charging signal from the electric vehicle with the second inductive coil. The controller may be adapted for bypassing the transformer from the power converter and for feeding the power to the first inductive coil transferred from the power converter, when a charging signal is received by the wireless receiver. Electric vehicles equipped with wireless charging technology may have a wireless transmission link (such as a WLAN radio transmission link) with the charging system.

In general, the hybrid charging system may be adapted for automatically detecting the requested charging technology based on wireless communication between the electric vehicle and the hybrid charging system.

According to an embodiment of the invention, the hybrid charging system further comprises at least one compensation capacitor connected between the power converter and a connection point between the transformer and the first induction coil. The at least one compensation capacitor may be present for forming an oscillating circuit with the primary winding of the transformer or the first inductive coil. The oscillating circuit may be formed, when the corresponding switch is open.

In other words, the compensation capacitor (s) of the wireless power transfer part of the hybrid charging system may be integrated and/or shared with the wired power transfer part. Sharing the compensation capacitors may save components and costs for the hybrid charging system.

The one or more compensation capacitors may be combined with further passive components, such as inductors and/or resistors to adapt the resonance and/or filter behaviour of the circuit.

It has to be noted that also the second inductive coil and a corresponding compensation capacitor may form such an oscillating circuit, which may be provided by an electric vehicle. The two oscillating circuits may be in resonance to improve the power transfer. In this way, an energy transmission with efficiency of up to 95%can be achieved.

In particular, the inductive power transfer via the first and second inductive coil may require a resonant circuit, since a large winding separation may have a relatively large leakage inductance and AC winding resistances. Furthermore, the magnetizing flux may be significantly reduced, which results in a much lower magnetizing inductance and mutual inductance. For the first and second inductive coil operating at a frequency well below its self-resonant frequency, one or more additional compensation capacitors are needed to form the resonant circuit in both sides.

A basic requirement for a compensation capacitor may be to resonate with the corresponding inductance, to provide the reactive power required for the inductances to generate an adequate magnetic field. For both inductive coils, the compensation capacitor (s) may minimize the input apparent power and/or may minimize the volt-ampere rating of the power supply.

According to an embodiment of the invention, the at least one compensation capacitor is connected between the power converter and a first switch for bypassing the power transferred to the transformer from the power converter and a second switch for bypassing the power transferred to the first inductive coil from the power converter.

According to an embodiment of the invention, a compensation capacitor is connected in series with the primary winding of the transformer and with the first inductive coil and/or a compensation capacitor is connected in parallel with the second inductive coil. It may be possible that more than one compensation capacitor are present.

According to an embodiment of the invention, the power converter comprises a grid side AC-to-DC converter and a primary side DC-to-AC converter. A DC link with a DC link capacitor may be connected between the AC-to-DC converter and the DC-to-AC converter. As already mentioned above, the primary side AC-to-DC converter and the following components (i.e. transformer part or inductive coil part) of each charging topology may be seen as DC-to-DC converter. This DC-to-DC converter may be connected via the DC link with the grid side AC-to-DC converter.

There are several possible topologies for the AC-to-DC converter and the DC-to-AC converter, which, however, are not limited by the following embodiments.

According to an embodiment of the invention, the DC-to-AC converter is a full-bridge converter. A full-bridge converter may comprise a half-bridge for each phase of the converter. A half-bridge may comprise two series-connected switching devices, such as transistors or thyristors.

In general, the grid side AC-to-DC converter may be an active front end or passive front end. It may be a single phase or a three phase converter.

According to an embodiment of the invention, the AC-to-DC converter comprises a boost converter and/or a passive rectifier. A boost converter may comprise an inductance connected in series with a diode and switching device, such as a transistor or thyristor that is connected between the inductance and the diode. The passive rectifier may generate a DC voltage that is boosted by the boost converter.

According to an embodiment of the invention, the AC-to-DC converter comprises a full-bridge converter. It has to be noted that the AC-to-DC converter may be a one-phase or three-phase converter. The DC-to-AC converter may be a one-phase converter.

Furthermore, the AC-to-DC converter may comprise a passive input filter, which may be composed of inductances and/or capacitors.

Also the secondary side AC-to-DC converter may have different topologies, which are not limited by the embodiments described in the following. For example, the secondary side DC-to-AC converter may comprise a diode bridge rectifier and optionally a filter.

A further aspect of the invention relates to a charging system arrangement, which comprises a hybrid charging system as described in the above and in the following and two electric cars, which may be charged either by the wired topology or by the wireless topology.

A first electric vehicle with a second inductive coil may be adapted for being inductively coupled with the first inductive coil provided by the hybrid charging system, wherein the first electric vehicle is adapted for being charged by the hybrid charging system.

A second electric vehicle may be adapted for being connected with the hybrid charging system with a cable, wherein the second electric vehicle is adapted for being charged by the hybrid charging system.

The hybrid charging system may be adapted for selectively charging the first electric vehicle or the second electric vehicle via the power converter. When only the first electric vehicle is connected to the hybrid charging system via a cable, the hybrid charging system may be switched via the first and second switch that the first electric vehicle is charged via the transformer and the secondary side AC-to-DC converter. The first inductive coil may be bypassed from the power converter.

When the second electric vehicle is positioned such that the first inductive coil and the second inductive coil are inductively coupled, a wireless sender of the electric car may inform the hybrid charging system that the second electric car is present for charging. In this case, the hybrid charging system may be switched via the first and second switch such that the second electric vehicle is charged via the first and second inductive coils. The transformer then may be bypassed from the power converter.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Brief Description of the Drawings

The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the drawings, in which:

Fig. 1 schematically shows a charging system arrangement according to an embodiment of the invention.

Fig. 2 schematically shows a hybrid charging system according to an embodiment of the invention.

Fig. 3 schematically shows a hybrid charging system according to a further embodiment of the invention.

Fig. 4 shows a schematic circuit diagram for a grid side AC-to-DC converter of a hybrid charging system according to an embodiment of the invention.

Fig. 5 shows a schematic circuit diagram for a further grid side AC-to-DC converter of a hybrid charging system according to an embodiment of the invention.

Fig. 6 shows a schematic circuit diagram for a DC-to-AC converter of a hybrid charging system according to an embodiment of the invention.

Fig. 7 shows a schematic circuit diagram for a secondary side AC-to-DC converter for a hybrid charging system according to an embodiment of the invention.

The reference symbols used in the drawings, and their meanings, are listed in summary form in the list of reference symbols. In principle, identical parts are provided with the same reference symbols in the figures.

Preferred Embodiments of the Invention

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Note, the headings are for organizational purposes only and are not meant to be used to limit or interpret the description or claims. Furthermore, note that the word "may" is used throughout this application in a permissive sense (i.e., having the potential to, being able to) , not a mandatory sense (i.e., must) . " The term "include" , and derivations thereof, mean "including, but not limited to" . The term "connected" means "directly or indirectly connected" , and the term "coupled" means "directly or indirectly connected" .

Fig. 1 shows a charging system arrangement 10 comprising a hybrid charging system 12 and two

electric vehicles

14, 15.

The hybrid charging system 12 comprises a main part 16, which is adapted for converting power from a power source 18 into AC power. For example, the main part 16 may convert an AC current from an electrical grid 18 into an AC current of different, usually much higher frequency, which is supplied via a first cable 20 to a ground adapter 22, in which a first inductive coil 24 is arranged. As an alternative, the main part 16 may be configured to convert a DC power from a DC power source into AC power output.

The main part 16, for example, may be connected to a wall. The ground 22 may be arranged below the electric vehicle 14 in a ground 26, for example in a parking lot.

When the electric vehicle14 is positioned suitable above the ground adapter 22, the first inductive coil 24 is inductively coupled via an air gap with a second inductive coil 28 in an on-board charging device 30 of the electrical vehicle 14. The AC current induced in the second inductive coil 28 is rectified by an AC-to-DC converter 32 inside the electric vehicle 14 and supplied to a battery 34 of the electric vehicle 14.

The ground adapter 22 may comprise a wireless receiver 36 and the on-board charging device 30 may comprise a wireless sender 38 for indicating the main hybrid charging system 12 that an electric vehicle needs to be charged wirelessly.

The main part 16 of the hybrid charging system 12 is additionally adapted for converting the AC current from an electrical grid 18 into a DC current, which is supplied via a second cable 40 to the second electric vehicle 15, which battery 34 may be charged directly with the DC current. It has to be noted that it may be possible that the hybrid charging system 12 may be adapted for solely charging one of the

electric vehicles

14, 15 at one time. It may be that only one

electric vehicle

14, 15 is connected with the hybrid charging system 12.

Fig. 2 shows the wireless charging system 12 in more detail. Where the power source 18 is an AC power source, for example an electric AC grid, the main part 16 comprises a power converter 42 that is connected via a transformer 44 with a secondary side AC-to-DC converter 46 and a controller 48 for controlling the power converter 42. In particular, the Power converter 42 comprises a grid side AC-to-DC converter 50 and a primary side DC-to-AC converter 52, which are connected via a DC link 54 with a DC link capacitor 56. As an alternative, where the power source is a DC power source, for example an battery, the main part may comprise a DC-to-AC converter that is connected via a transformer 44 with a secondary side AC-to-DC converter 46 and a controller 48 for controlling the DC-to-AC converter.

A first switch 58 is connected across the primary winding 60 of the transformer 44, such that a charging power transfers to the primary winding 60 of the transformer 44 from the AC-to-AC-converter 42 may be bypassed with the closed first switch 58. Otherwise, where it is open, the power transferred from the AC-to-AC-converter 42 will find its path towards the primary winding 60 of the transformer 44. . The primary winding 60 of the transformer 44 is inductively coupled with a secondary winding 62 via a common core. The secondary winding is connected to the AC-to-DC converter 46, which is connected with the charging cable 40.

The first inductive coil 24 is connected via the cable 20 in series to a primary winding 60 to the power converter 42. A second switch 64, which as the first switch 58 is arranged in the main part 16, is connected across the first inductive coil 24, such that a charging power transfers to the first inductive coil 24 from the AC-to-AC-converter 42 may be bypassed with the closed second switch 64. Otherwise, where it is open, the power transferred from the AC-to-AC-converter 42 will find its path towards the first inductive coil 24.

Furthermore, Fig. 2 shows a compensation capacitor 66, which is connected between the power converter 42 and the first switch 58 and the second switch 64.

The

switches

58, 64 may be controlled by the controller 48 to be open or closed. In a wired charging state, the switch 58 is controlled to be open and the switch 64 is controlled to be closed. In a wireless charging state, the switch 58 is controlled to be closed and the switch 64 is controlled to be open. In both states, the compensation capacitor 64 forms a resonant circuit with the respective inductance, i.e. the primary winding 60 or the first inductive coil 24.

The first switch 58 may be a normally open switch and the second switch 64 may be a normally closed switch. In such a way, the controller 48 may only need one control signal to move the switches in the wired charging state or the wireless charging state.

It has to be noted that also the second inductive coil 28 of the electric vehicle 14 may be connected with the compensation capacitor 68, forming a resonant circuit with the second inductive coil 28. Furthermore, the primary winding 60 of the transformer 44 may be connected in parallel and/or in series with further inductors 69, which may be arranged between the first switch 58 and the primary winding 60. These inductors 69 may form an LLC circuit with the capacitor 66.

In both the wired charging state and the wireless charging state, the controller controls switching devices of the AC-to-DC converter 50 to generate a DC current in the DC link 56 and controls switching devices of the DC-to-AC converter 52 to convert the DC current in the DC link 54 into the high frequency current. For example, the voltage in the grid 18 may have a voltage of 50 Hz or 60 Hz. On the other hand, the pulse width modulated current output by the power converter 42 may have a frequency of more than 10 kHz.

In the wired charging state, which is assumed by the hybrid charging system 12 without further information from the wireless receiver 36, the AC-to-DC converter 46 is supplied via the transformer 44 with the AC current from the power converter 42. The AC-to-DC converter 46 generates a DC current that is supplied to the electric vehicle 15 for charging its battery 34.

When an electric vehicle 14 is positioned above the ground adapter 22, the electric vehicle 14, with the wireless sender 38, may send a charging signal to the wireless receiver 36. The charging signal is received by the controller 48, which then switches the

switches

58, 64 into the wireless charging state. The AC current from the power converter is supplied to the first inductive coil 24. A corresponding AC current is induced in the second inductive coil 28 and converted into a DC current by the AC-to-DC converter 32 of the electric vehicle 14.

In Fig. 2, the compensation capacitor 66 is connected in series with the primary winding 60 and the first inductive coil 24. The compensation capacitor 68 is connected in series with the second inductive coil 28.

Fig. 3 shows a hybrid charging system 12, which differs from the charging system of Fig. 2 in that the compensation capacitor 66’is connected in parallel with the primary winding 60 and the first inductive coil 24. Furthermore, the compensation capacitor 68’is connected in parallel with the second inductive coil 28.

It has to be noted that the hybrid charging system 12 may have both a compensation capacitor 66 in series and a compensation capacitor 66’in parallel to the primary winding 60 and the first inductive coil 24. The same applies to the compensation capacitors 68, 68’inside the electric vehicle 14. Furthermore, a compensation capacitor 66 (or 66’) may be combined with a compensation capacitor 68’ (or 68) .

Fig. 4 shows an example for an AC-to-DC converter 50, which is composed of a passive rectifier 70 and a boost converter 72. The passive rectifier 70 comprises two diode half-bridges. The boost converter 72 comprises three paralleled arms of an inductance series-connected with a diode and a switching device 74, which is connected between the inductance and the diode. The switching devices 74 may be controlled by the controller 48.

Fig. 5 shows a further example for an AC-to-DC converter 50, which is composed of a passive input filter 76 and a three-phase full-bridge converter 78. The passive input filter 76 comprises three single-phase LC-filters, which are star-connected via capacitors. The full-bridge converter 78 comprises three half-bridges of series-connected switching devices 74. The switching devices 74 may be controlled by the controller 48.

Fig. 6 shows an example for a DC-to-AC converter 52, which is a single-phase full-bridge converter. The DC-to-AC converter 52 comprises two half-bridges of series-connected switching devices 74. The switching devices 74 may be controlled by the controller 48.

Fig. 7 shows an example for an AC-to-DC converter 46, which may be employed in the main part 16 and/or an example for an AC-to-DC converter 32, which may be employed in the on-board charging device 30. The AC-to-

DC converter

46, 32 comprises a passive rectifier 80 composed of two diode half-bridges and a CLC output filter 82. A diode may prevent an inverse current flow from the battery 34 into the rectifier AC-to-

DC converter

46, 32.

Though the present invention has been described on the basis of some preferred embodiments, those skilled in the art should appreciate that those embodiments should by no way limit the scope of the present invention. Without departing from the spirit and concept of the present invention, any variations and modifications to the embodiments should be within the apprehension of those with ordinary knowledge and skills in the art, and therefore fall in the scope of the present invention which is defined by the accompanied claims.

Claims

A hybrid charging system (12) for electric vehicles (14, 15) , the charging system (12) comprising:

a power converter (42) connectable to a power source (18) , for converting power from the power source (18) into AC power;

a transformer (44) connected with the power converter (42) with a primary winding (60) ;

a secondary side AC-to-DC converter (46) connected with a secondary winding (62) of the transformer (44) and for providing a DC current for power transfer to an electric vehicle (15) via a cable (40) ;

a first inductive coil (24) connected in series with the primary winding (60) of the transformer (44) and for inductively coupling to a second inductive coil (28) for power transfer to an electric vehicle (14) via an air gap.
The hybrid charging system (12) of claim 1, further comprising:

a first switch (58) connected across the primary winding (60) of the transformer (44) for bypassing power transfer to the primary winding (60) of the transformer (44) from the power converter (42) ;

a second switch (64) connected across the first inductive coil (24) for bypassing power transfer to the first inductive coil (24) from the power converter (42) .
The hybrid charging system (12) of claim 2,

wherein the first switch (58) is a normally open switch and the second switch (64) is a normally closed switch.
The hybrid charging system (12) of claim 2 or 3, further comprising:

a controller (48) for opening and closing the first switch (58) and the second switch (64) , such that solely the transformer (44) or solely the first inductive coil (24) is fed with power transferred from the power converter (42) .
The hybrid charging system (12) of claim 4,

wherein the controller (48) is adapted for receiving a wireless communication signal indicating a charging type of an electric vehicle (14) ;

wherein the controller (48) is adapted for opening and closing the first switch (58) and the second switch (64) according to the received charging type.
The hybrid charging system (12) of one of the previous claims, further comprising:

a wireless receiver (36) for receiving a charging signal from the electric vehicle (14) with the second inductive coil (28) ;

wherein the controller (48) is adapted for bypassing the power transfer to the primary winding (60) of the transformer (44) from the power converter (42) and for transferring the power to the first inductive coil (24) from the power converter (42) , when a charging signal is received by the wireless receiver (42) .
The hybrid charging system (12) of one of the previous claims, further comprising:

at least one compensation capacitor (66, 66’) interconnected between the power converter (42) and a connection point between the transformer (44) and the first induction coil (24) .
The hybrid charging system (12) of claim 7,

wherein the at least one compensation capacitor (66, 66’) is connected between the power converter (42) and a first switch (58) for bypassing power transfer to the transformer (44) from the power converter (42) and a second switch (64) for bypassing power transfer to the first inductive coil (24) from the power converter (42) .
The hybrid charging system (12) of claim 7 or 8,

wherein a compensation capacitor (66) is connected in series with the primary winding (60) of the transformer (44) and with the first inductive coil (24) .
The hybrid charging system (12) of one of claims 7 to 9,

wherein a compensation capacitor (68’) is connected in parallel with the second inductive coil (28) .
The hybrid charging system (12) of one of the previous claims,

wherein the power converter (42) comprises a grid side AC-to-DC converter (50) and a primary side DC-to-AC converter (52) ;

wherein a DC link (54) with a DC link capacitor (56) is connected between the AC-to-DC converter (50) and the DC-to-AC converter (52) .
The wireless charging system (12) of claim 11,

wherein the DC-to-AC converter (50) comprises a full-bridge converter (78) .
The wireless charging system (12) of claim 11 or 12,

wherein the AC-to-DC converter (50) comprises a boost converter (52) and/or a passive rectifier (70) ; or

wherein the AC-to-DC converter (14) comprises a full-bridge converter (58) .
The hybrid charging system (12) of one of the previous claims,

wherein the secondary side AC-to-DC converter (52) comprises a diode bridge rectifier.
A charging system arrangement (10) , comprising:

a hybrid charging system (12) according to one of the previous claims;

a first electric vehicle (14) with a second inductive coil (28) adapted for being inductively connected with the first inductive coil (24) provided by the hybrid charging system (12) , wherein the first electric vehicle (14) is adapted for being charged by the hybrid charging system (12) ;

a second electric vehicle (15) adapted for being connected with the hybrid charging system (12) with a cable (40) , wherein the second electric vehicle (15) is adapted for being charged by the hybrid charging system (12) ;

wherein the hybrid charging system (12) is adapted for selectively charging the first electric vehicle (14) or the second electric vehicle (15) via the power converter (42) .