The present disclosure is related to a charging apparatus , a charging arrangement and a method for providing a charging power .

Document WO 2015/ 103164 Al describes a battery based DC fast charging system . The system is configured to provide DC fast charging capabilities to an electric vehicle charging station and to recharge a battery system of the charging station by utili zing a renewable energy collection system and singlephase connection to a grid . A user connects an electric vehicle to the charging station and requests a battery recharge . Power is delivered to the electric vehicle ( abbreviated EV) by the battery system of the charging station . The battery system is recharged by a renewable energy collection system and power from the grid . Only one electric vehicle can be charged by a DC/DC charger of the charging station .

In many applications - such as multiple EV charging units installed in residential , commercial and business buildings - DC charging is a useful feature but installing DC capable EV charging units is expensive and therefore only AC capable EV charging units are provided .

It is an obj ect to provide a charging apparatus and a method for providing a charging power with high cost ef ficiency .

These obj ects are achieved by the subj ect-matter of the independent claims . Further developments and embodiments are described in the dependent claims . There is provided a charging apparatus , comprising a power input , a power converter with an input coupled to the power input and an output for providing a DC voltage , a change-over switch, a first number N of DC output terminals coupled via the change-over switch to the output of the power converter, and a controller coupled to a control terminal of the change- over switch . The first number N is larger than 1 .

Advantageously, the power converter of the charging apparatus is configured to provide the DC voltage to a selected DC output terminal of the first number N of DC output terminals and thus to a selected electric vehicle . Thus , there is no need to arrange a first number of power converters downstream of the first number N of DC output terminals . Thus , a high cost ef ficiency is achieved .

In an example , the first number N is larger than two , larger than five or larger than 10 .

In an embodiment of the charging apparatus , the power converter is configured to provide di f ferent values of a DC voltage . Thus , the power converter has a variable conversion factor .

In an embodiment of the charging apparatus , the controller is coupled to a control terminal of the power converter and is configured to set the value of the DC voltage . Thus , the controller sets the conversion factor of the power converter .

The controller includes e . g . a microcontroller or microprocessor .

In an example , the controller is configured to perform voltage measurements e . g . at least at one terminal or connection line of a group comprising the power input , the first number N of DC output terminals , an input side of the power converter and an output side of the power converter . The controller is configured to perform current measurements e . g . at least at one terminal or connection line of a group comprising the power input , the first number N of DC output terminals , an input side of the power converter and an output side of the power converter .

In an embodiment of the charging apparatus , the charging apparatus is configured to provide power at a maximum of one DC output terminal of the first number N of DC output terminals at a point of time . Thus , the charging apparatus does not provide power to two or more than two DC output terminals at a point of time . Thus , a short circuit between batteries of electric vehicles is avoided . The charging apparatus may be idle , and thus may not provide any power at another point of time .

In an embodiment of the charging apparatus , the power input is a DC input . The power converter is implemented as a DC/DC converter .

In a further development of the charging apparatus , the charging apparatus comprises a further power input that is an AC input and a further power converter which is implemented as an AC/DC converter . The further power converter includes an input coupled to the further power input and an output coupled to an input side of the change-over switch .

In an embodiment of the charging apparatus , the further power converter is configured to provide di f ferent values of the DC voltage . The controller is coupled to a control terminal of the further power converter . The controller is configured to set the value of the DC voltage .

In an embodiment of the charging apparatus , the power input is an AC input and the power converter is implemented as an AC/DC converter . In an example , the charging apparatus comprises a further power input that is a DC input and a further power converter which is implemented as a DC/DC converter . The further power converter includes an input coupled to the further power input and an output coupled to an input side of the change-over switch .

In an embodiment of the charging apparatus , the power converter and the further power converter are both configured to provide di f ferent values of the DC voltage . The controller is coupled to the control terminal of the power converter and to the control terminal of the further power converter . The controller is configured to set the value of the DC voltage provided by the power converter and the further power converter . In an example , the controller is configured to activate a maximum of one of the power converter and the further power converter at a point of time .

In an example , the change-over switch is reali zed by a first number N of semiconductor switches or a first number N of circuit breakers .

In an example , the charging apparatus is configured to provide an overcurrent protection . The charging apparatus includes a current sensor which sets the change-over switch in an idle state . For example , the current sensor sets each of the first number N of semiconductor switches or the first number N of circuit breakers in a non-conducting state . The current sensor is e . g . located between the output of the power converter and an input of the change-over switch .

In an example , the charging apparatus includes an auxiliary power supply . The auxiliary power supply is fed e . g . via the power input or via a supply input coupled to an AC grid .

There is provided a charging arrangement , comprising the charging apparatus and an electric vehicle charging unit .

In an embodiment of the charging arrangement , the electric vehicle charging unit comprises an AC input , a DC input coupled to one DC output terminal of the first number N of DC output terminals , and a charger output configured to be coupled to an electric vehicle .

In an embodiment of the charging arrangement , the charging arrangement comprises a second number of electric vehicle charging units . The second number is less or equal to the first number . Thus , each of the second number of electric vehicle charging units is coupled on its DC input to a separate DC output terminal of the first number N of DC output terminals . There may be one or more than one DC output terminals without connection to an electric vehicle charging unit .

In an embodiment of the charging arrangement , the electric vehicle charging unit is configured that power in the form of an AC current is provided from the AC input to the charger output in a first state , power in the form of a DC current is provided from the DC input to the charger output in a second state , and no power is provided to the charger output in a third state . Thus , the third state is an idle state . In an example , in the first state , power is provided to the charger output exclusively from the AC input . In the second state , power is provided to the charger output exclusively from the DC input .

In an embodiment of the charging arrangement , the electric vehicle charging unit comprises a switching arrangement . The switching arrangement couples the AC input to the charger output in the first state . The switching arrangement couples the DC input to the charger output in the second state . The switching arrangement neither couples the AC input nor the DC input to the charger output in the third state .

In an embodiment of the charging arrangement , the electric vehicle charging unit is configured to provide slow charging with an AC current in the first state and fast charging with a DC current in the second state .

In an embodiment of the charging arrangement , the charger output of the electric vehicle charging unit includes at least a first and a second terminal . The first terminal is coupled to the AC input of the electric vehicle charging unit and is configured for providing AC current . The second terminal is coupled to the DC input of the electric vehicle charging unit and is configured for providing DC current .

In an embodiment of the charging arrangement , the electric vehicle charging unit comprises a protection circuit coupled to the AC input and configured to detect at least one of an overcurrent condition and a leakage current condition .

In an embodiment of the charging arrangement , the electric vehicle charging unit is free of a DC/DC converter that is arranged between the DC input and the charger output . Thus , the electric vehicle charging unit can be reali zed with high cost ef ficiency . In an example , the electric vehicle charging unit is free of an AC/DC converter arranged between the AC input and the charger output .

In an example , the electric vehicle charging unit includes an AC/AC converter arranged between the AC input and the charger output .

In an embodiment of the charging arrangement , the electric vehicle charging unit comprises a charger controller that is coupled to the controller of the charging apparatus . The charger controller includes a communication terminal that is configured to communicate with an electric vehicle .

In an embodiment , the charging arrangement includes a communication bus which couples the charger controller to the controller of the charging apparatus . The controller of the charging apparatus is configured e . g . to use the open charge point protocol ( abbreviated OCPP ) for communication to the charger controller of the electric vehicle charging unit and/or for communication to a central management system .

In an example , an electric vehicle arrived at the electric vehicle charging unit provides information via the charger controller to the controller of the charging apparatus . The information includes at least one item of a group comprising a nominal voltage of the battery of the electric vehicle , a state of charge of the battery of the electric vehicle and a request for fast DC charging . Since di f ferent types of electric vehicles have di f ferent values of the nominal voltage , this information is appropriate for the controller of the charging apparatus to control the power converter and to set an appropriate value of the DC voltage provided by the power converter .

In an embodiment of the charging arrangement , the power converter is a bidirectional converter . Thus , the charging arrangement is configured that a battery of an electric vehicle provides power via the electric vehicle charging unit , the change-over switch and the power converter to the power input . In this case , the power input is configured as power output or power input/output .

In an example , the power converter incorporates a high frequency trans former .

In an example , the power converter includes a dual active bridge .

There is provided a method for providing a charging power, comprising providing power via a power input to a power converter, providing a DC voltage by the power converter, controlling a change-over switch by a controller, and providing the DC voltage via the change-over switch to a DC output terminal of a first number N of DC output terminals . The first number N is larger than 1 .

The charging apparatus and the charging arrangement described above are particularly suitable for the method for providing a charging power . Features described in connection with the charging apparatus , the electric vehicle charging unit and the charging arrangement can therefore be used for the method and vice versa . There is provided an electric vehicle charging unit which comprises an AC input , a DC input and a charger output configured to be coupled to an electric vehicle .

The charging apparatus , the charging arrangement and the method for providing a charging power described above are particularly suitable for the electric vehicle charging unit . Features described in connection with the charging apparatus , the charging arrangement and the method can therefore be used for the electric vehicle charging unit and vice versa .

In an example , the charging arrangement is configured to supply AC and DC voltage to multiple electric vehicle charging units for both slow and fast charging . An electric vehicle charging unit ( abbreviated EV charging unit ) can also be named electric vehicle charger or electrical vehicle charging station . The charging arrangement includes a system design to deliver both AC and DC voltage supply inputs to multiple EV charging units without adding power conversion stages inside the EV charging units . This architecture can be used in many applications where multiple EV charging units are installed and it provide them with AC and DC ( slow and fast ) charging capability .

In an example , the charging arrangement reali zes a system to provide AC and DC voltage supply to multiple EV charging stations for both slow and fast charging features , facilitating the interface of EV charging units to AC and DC microgrids and power systems . The EV charging unit allows the supply of AC and DC power, respectively, from AC and DC inputs , eliminating an AC/DC conversion stage inside the EV charging unit ( such an AC/DC conversion stage makes EV charging units more expensive and bigger ) . EV charging units that are used to supply AC charging can also be used for DC charging purpose , by implementing a DC and/or AC receiving and protection circuit inside the EV charging unit or the charging apparatus and by reali zing a communication interface of the EV charging unit with the charging apparatus . The charging apparatus contains a power converter shared by multiple EV charging units . The charging apparatus can also be named charging cabinet or DC charging cabinet . The charging apparatus is external to the EV charging unit .

In an example , the charging arrangement is advantageous with the growing of EV charger installations in many use cases , leaving to the user the choice between slow (AC ) and fast ( DC ) charging prior to the beginning of a charging session, e . g . without a limit from the electrical installation . Therefore , sharing an external power converter is a cost- ef fective solution that in an example can also solve the task of reservation and occupation of a charger plug . I f a car, after reaching the target state of charge ( abbreviated SoC ) , is still occupying the EV charging unit , another car approaching the EV charging unit can have the DC supply without need for the yet occupied plug, j ust by a switch of the selector relay at the charging apparatus . This would not be possible i f a DC charger is installed, rather than a shared converter for all chargers .

In an example , the charging arrangement of fers great flexibility, as it is possible to decide the power capacity of both power inputs and the si ze of the external converter, according to the needs of the application .

The following description of figures of embodiments may further illustrate and explain aspects of the charging apparatus , the electric vehicle charging unit , the charging arrangement and the method . Parts and devices with the same structure and the same ef fect , respectively, appear with equivalent reference symbols . In so far as parts or devices correspond to one another in terms of their function in di f ferent figures , the description thereof is not repeated for each of the following figures .

Figure 1 shows an example of a charging arrangement with a charging apparatus and an electric vehicle charging unit ; and

Figure 2 shows a further example of a charging arrangement with a charging apparatus and an electric vehicle charging unit .

Figure 1 shows an example of a charging arrangement 10 with a charging apparatus 14 and an electric vehicle charging unit 11 . In Figure 1 , a single line diagram is shown for describing the charging arrangement 10 . The charging apparatus 14 comprises a power input 15 , a power converter 16 , a change-over switch 17 , a first number N of DC output terminals 21 - 23 and a controller 24 . The first number N is larger than 1 . The first number N of DC output terminals 21 - 23 is coupled via the change-over switch 17 to the output of the power converter 16 . The controller 24 is coupled to a control terminal of the change-over switch 17 . The power converter 16 includes an input coupled to the power input 15 and an output for providing a DC voltage VDC .

The charging arrangement 10 comprises multiple electric vehicle charging units 11 to 13 that are supplied by two input voltage ports , namely an AC input 30 and a DC input 31 . The supply of an AC voltage VAC is done for AC charging, with sinusoidal supply voltage that is trans ferred to the on-board charger of an electric vehicle 33 ( abbreviated EV) that rectifies the AC voltage VAC in DC form for a battery (not shown) of the electric vehicle 33.

The DC input 31, 31' , 31' ' is available to each EV charging unit 11 to 13. The DC input 31, 31' , 31' ' is supplied by an external common power converter 16 placed in the separate charging apparatus 14 that is shared by every EV charging unit 11 to 13. The power converter 16 is a DC/DC converter or an AC/DC converter. The charging apparatus 14 can be named cabinet. The EV charging unit 11 and the charging apparatus 14 are separate devices or arrangements.

The realization of the power converter 16 as a DC/DC converter facilitates the integration of EV charging units 11 to 13 into a DC based microgrid 50 and power systems with presence of distributed renewable DC sources 53, reduces the conversion losses and gives galvanic separation from the external grid 51, 55. The conversion losses are reduced as a DC/DC converter has one conversion stage less than an AC/DC converter, and galvanic separation is offered by a high- frequency transformer inside the power converter 16. The microgrid 50 includes e.g. a DC grid 51, a DC distribution panel 52, a DC source 53 and/or a load 54. The DC source 53 is e.g. a photovoltaic arrangement or a battery.

Each of the first number N of EV charging units 11 to 13 comprises a protection circuit 37, a power receiving circuit 38 (for AC and DC) , a charger controller 39 and a cable assembly and outlet 40. The further EV charging units 12, 13 are realized such as the EV charging unit 11. The protection circuit 37 is configured as insulating monitoring device, abbreviated IMD. The protection circuit 37 is designed for leakage control and/or residual current control, e.g. for the AC input 30 and the AC part of the EV charging unit 11. A leakage control for the DC input 31 and the DC part of the EV charging unit 11 is performed e . g . by the charging apparatus 14 . The power receiving circuit 38 is coupled on its input side to the AC input 30 and the DC input 31 and on its output side to a charger output 32 .

The DC charging event is exclusive for one EV charging unit 11 to 13 per time , as all of them will share the DC voltage VDC provided by the output of the power converter 16 . During the charging event , the power converter 16 matches the voltage level required by the battery of the EV 33 . Therefore , a change-over switch 17 is placed at the output of the power converter 16 , as shown in the shared cabinet 14 in Figure 1 . The change-over switch 17 can be named selection relay . The switching of the change-over switch 17 is controlled by a controller 24 of the charging apparatus 14 . The charging apparatus 14 receives information regarding which EV charging unit 11 to 13 is asked to supply DC charging . This information is sent by the charger controller 39 that is placed inside each EV charging unit 11 to 13 . The charger controller 39 is reali zed as a communication control unit . A communication terminal 41 of the charger controller 39 communicates with the electric vehicle 33 . The controller 24 inside the charging apparatus 14 performs the voltage or current control mode regulation of the power converter 16 , following the request of the electric vehicle 33 that is collected by the charger controller 39 of the EV charging unit 11 . A communication bus 45 couples the charger controller 39 to the controller 24 of the charging apparatus 14 .

In this way, every time a user comes to one of the first number N of EV charging units 11 to 13 and asks for AC charging, this can be facilitated through the charger controller 39 and pulse-width modulation signaling (abbreviated PWM signaling) , as per AC charging standard, with power supplied from a public AC grid 55.

Instead, when a user asks for direct current supply, the charging session will work e.g. according to the CCS Combo 2 standard, performing a powerline communication (abbreviated PLC communication) between the charger controller 39 and a controller of the EV 33, prior the communication to the controller 24 of the charging apparatus 14 to close the circuit of the interested EV charging unit 11 to 13.

The cable assembly and outlet 40 of each EV charging unit 11 to 13 is e.g. equipped with a unified plug. Each EV charging unit 11 to 13 has a charger output 32, 32' , 32' ' . The charger output 32, 32' , 32' ’ is implemented by one plug or cable. Thus, the user has the choice between AC and DC charging. Advantageously, the charging arrangement 10 exploits and improves e.g. the current CCS Combo 2 standard for AC and DC charging .

As described above, the power converter 16 is a DC/DC converter .

In an alternative embodiment, the power converter 16 is an AC/DC converter. Thus, the charging arrangement 10 is implemented e.g. for an application where there is no DC grid connection. The EV charging units 11 to 13 are supplied both by the public AC grid 55 (through the AC input 30) and a separate AC microgrid by the power converter 16 realized as AC/DC converter (replacing the DC/DC converter) that will supply the EV charging units 11 to 13 through the DC input 31 for DC charging. Figure 2 shows a further example of a charging arrangement 10 with a charging apparatus 14 and an electric vehicle charging unit 11 which is a further development of the examples shown in Figure 1 . The charging apparatus 14 comprises a further power input 57 that is an AC input and a further power converter 56 . The further power converter 56 is implemented as an AC/DC converter and includes an input coupled to the further power input 57 and an output coupled to an input side of the change-over switch 17 . The further power converter 56 is able to provide di f ferent values of the DC voltage VDC . The controller 24 is connected to a control terminal of the further power converter 56 . The controller 24 is able to set the value of the DC voltage VDC . Thus , the further power converter 56 that is reali zed as an AC/DC converter is , in the same way as the converter 16 ( reali zed as a DC/DC converter ) , controlled by the controller 24 so that the further power converter 56 can adj ust the reference voltage output according to the desired voltage request by the battery of the electric vehicle 33 . So the same control method for the operation of the power converter 16 is applied al so for the operation of the further power converter 56 .

In an example , an output of the power converter 16 and an output of the further power converter 56 are both connected to an input of the change-over switch 17 . The controller 24 sets either the power converter 16 or the further power converter 56 or none of them in an active state . Thus , a short circuit at the output sides of the two converters 16 , 56 is avoided . The dashed lines in Figures 1 and 2 are connection lines carrying a signal or signals and the solid connection lines are reali zed as power lines .

Moreover, the EV charging unit 11 comprises a switching arrangement 42 . The switching arrangement 42 couples the AC input 30 to a first terminal 43 of the charger output 32 in a first state. The first terminal 43 is an AC output. The switching arrangement 42 couples the DC input 31 to a second terminal 44 of the charger output 32 in a second state. The second terminal 44 is a DC output. The switching arrangement 42 neither couples the AC input 30 nor the DC input 31 to any of the terminals 43, 44 of the charger output 32 in a third state. The further EV charging units 12, 13 are realized such as the EV charging unit 11.

The AC grid 55 is e.g. a two phase grid or three phase grid. Thus, two or three cables comprised by the AC grid 55 are connected to the AC input 30.

The power converter 16 receives power for its control from external (e.g. from the AC grid 55 or an auxiliary power supply of the charging apparatus 14) or generates the power for control itself.

The embodiments shown in Figures 1 and 2 as stated represent examples of the improved charging apparatus 14, electric vehicle charging unit 11, charging arrangement 10 and method; therefore, they do not constitute a complete list of all embodiments according to the improved charging apparatus, electric vehicle charging unit, charging arrangement and method. Actual charging apparatus, electric vehicle charging units, charging arrangements and methods may vary from the embodiments shown in terms of parts, devices, couplings and structures, for example. Reference symbols

10 charging arrangement

11 - 13 electric vehicle charging unit

14 charging apparatus

15 power input

16 power converter

17 change-over switch

21 - 23 DC output terminal

24 controller

30, 30' , 30' ' AC input

31, 31' , 31' ' DC input

32, 32' , 32' ' charger output

33 - 35 electric vehicle

37, 37 ' , 37' ' protection circuit

38, 38' , 38' ’ power receiving circuit

39, 39' , 39' ’ charger controller

40, 40' , 40' ’ cable assembly and outlet

41, 31' , 41' ’ communication terminal

42 switching arrangement

43, 44 terminal

45 communication bus

50 microgrid

51 DC grid

52 DC distribution panel

53 DC source

54 load

55 AC grid

56 further power converter

57 further power input

VAC AC voltage

VDC DC voltage