DE102022108027A1 - Electrical charging infrastructure - Google Patents

Abstract

The invention relates to an electrical charging infrastructure (12) for establishing a conductive connection to a vehicle contact unit (16). The charging infrastructure (12) has a ground contact unit (18) which has a plate-shaped base body (26) and a plurality of contacts (30) which are arranged on a loading surface (28) of the base body (26). The plurality of contacts (30) include power contacts (32) that are assigned to at least one potential level. The power contacts (32) are each connected in series to a contact switch (38). The contact switches (38) are designed as mirror contacts, so that each contact switch (38) comprises a main contact (40) and a monitoring contact (42), which are mechanically coupled but are galvanically isolated from one another. The charging infrastructure (12) has a monitoring circuit (20) which is set up to monitor at least the respective switching position of the monitoring contacts (42) of the contact switches (38), which are assigned to power contacts (32) which are not contacted when there is a conductive connection . The monitoring circuit (20) is set up to control a shutdown device (22).

Description

The invention relates to an electrical charging infrastructure for establishing a conductive connection to a vehicle contact unit.

In the case of at least partially electrically powered vehicles, such as plug-in hybrid vehicles and purely electric vehicles, the vehicle batteries must be charged regularly, preferably after each journey. For this purpose, the vehicle is connected to a corresponding power source, usually using a plug, for example a so-called Type 2 plug, which must be manually plugged into a corresponding socket on the vehicle by a person.

From the prior art, for example WO 2019/052962 A1 , ground contact units for vehicle battery charging systems that are provided on the ground are also known. The ground contact units can automatically establish a conductive connection with a corresponding vehicle contact unit provided on the vehicle to be charged in order to charge the vehicle. The vehicle contact unit can be provided on the underbody of the vehicle, moving downwards in order to establish electrical contact with the ground contact unit.

For example, the ground contact unit is designed as a so-called matrix charging pad, as described in the WO 2019/052962 A1 is shown. For this purpose, the ground contact unit comprises a plurality of contact areas which are arranged in a matrix, wherein the contact areas can be contacted by means of the vehicle contact unit in order to establish an electrical connection between the ground contact unit and the vehicle contact unit. Depending on the contact point of the connector of the vehicle contact unit, the correspondingly occupied contact areas of the ground contact unit are switched on in order to establish the electrical connection via these contact areas.

Typically, the occupied contact areas are switched on using separate relays that are assigned to each power contact of the ground contact unit. This results in a so-called matrix relay, which, among other things, ensures the safety-relevant requirements regarding the insulation distance of the individual switches. In addition, two relays are typically connected in series per power contact to guarantee appropriate redundancy and reliability. In addition, the multiple relays ensure that the ground contact unit is ready to carry out a charging process by first opening all relays so that all power contacts are switched potential-free.

However, the large number of relays and their interconnection lead to correspondingly high costs.

The object of the invention is to make the charging infrastructure more efficient in terms of its structure.

The object is achieved according to the invention by an electrical charging infrastructure for establishing a conductive connection to a vehicle contact unit. The charging infrastructure has a ground contact unit which has a plate-shaped base body and a plurality of contacts which are arranged on a loading area of the base body, against which the vehicle contact unit can come into contact. The multiple contacts include at least power contacts that are assigned to at least one potential layer. The power contacts are each connected in series with a contact switch. The contact switches are each designed as mirror contacts, so that each contact switch includes a main contact and a monitoring contact, which are mechanically coupled but are galvanically isolated from each other. The charging infrastructure has a monitoring circuit that is set up to monitor at least the respective switching position of the monitoring contacts of the contact switches, which are assigned to power contacts that are not contacted when there is a conductive connection. The monitoring circuit is set up to control a shutdown device.

The basic idea of the invention is to make the ground contact unit simpler in that the power contacts are only assigned to one contact switch instead of two relays connected in series, whereby the number of relays used can be significantly reduced, which increases efficiency and at the same time reduces costs. The contact switches are designed as mirror contacts, so that a current can flow through their main contact when it is closed, with the switching position being monitored at the same time by the monitoring contact being monitored by the monitoring circuit, in particular the position of the monitoring contact. By monitoring the monitoring contact, it is possible to check the corresponding position of the main contact of the contact switch designed as a mirror contact, since the main contact and the monitoring contact are mechanically coupled to one another. In other words, this ensures that the main contact designed as a relay has actually reached the required opening distance in order to ensure the desired galvanic isolation, since only then is the monitoring contact in the closed position, which corresponds to the monitoring circuit is determined accordingly. Undesirable welding or sticking of the main contact would thus be able to be detected, among other things, so that appropriate measures could be taken.

In addition, according to the invention, incorrect control of one of the contact switches can generally be detected, for example caused by a problem with the (control) electronics and/or by a software problem. Such a determination is particularly relevant during a charging process.

In addition, for this type of monitoring it is possible for the position of the contact switches, in particular the position of the main contacts of the contact switches, to be monitored when the contact switches are in the non-current-carrying position, i.e. when the main contact is open. This corresponds to the intended position of the power contacts, which are not contacted when the conductive connection is established. With other monitoring systems, however, only the closed position can be monitored, since a corresponding signal path or current flow is necessary, which is evaluated in order to detect a faulty position.

Of course, the monitoring circuit can additionally monitor the respective switching positions of the contact switches, which are contacted by the vehicle contact unit. As explained above, due to the mechanical coupling, this will also take place via the associated monitoring contact of the contact switch, which is then in the open position since the associated main contact is in the closed position.

The ground contact unit can basically be placed on a road surface or embedded in it. Accordingly, the ground contact unit is also referred to as a “pad”.

The multiple contacts that are arranged on the loading surface of the base body of the ground contact unit can be of different types. In any case, the contacts include power contacts that are necessary for the charging process, since the charging current is conducted via the power contacts. The power contacts are contacts that are assigned to a neutral potential position (“neutral”) or to a specific phase. Up to three phases (P1, P2, P3) or even more phases can be provided. The assignment of the respective potential level to the power contacts can also be designed variably, so that switching the potential level is possible.

In addition to the power contacts, the plurality of contacts can also have at least one control contact (CP contact), via which a control signal is passed in order to determine contacting of the ground contact unit during a contacting check, in particular the actual contacting area of the loading area by the vehicle contact unit.

Alternatively or additionally, the contacts can have at least one protective conductor contact in addition to the power contacts. In principle, several protective conductor contacts, which are designed separately, can be provided. Alternatively, it can also be provided that the entire loading area is designed as a protective conductor level through which the power contacts and optionally the control contacts extend, the different types of contacts being electrically insulated from the protective conductor level by means of an annular insulating area.

The loading area of the base body is an exposed loading area, provided that the ground contact unit is prepared for the charging process. This means that the loading area can basically be exposed. It can also be provided that a cover temporarily covers the loading area when not in use, with the cover being removed manually or automatically to expose the loading area so that a charging process can take place. In any case, the contacts are located on the outside of the loading area so that they are freely accessible provided the optional cover has been removed. The loading area is therefore also referred to as an exposed loading area, as it is based on the condition that exists when a charging process takes place or shortly before.

The charging infrastructure monitoring circuitry may be fully integrated into the ground contact unit itself, so that all monitoring is performed in the ground contact unit. Alternatively, it can be provided that the monitoring circuit consists of several sub-circuits which are provided in the ground contact unit and in at least one separately designed monitoring unit, whereby the monitoring circuit is designed in two or more parts. It can also be provided that the monitoring circuit of the charging infrastructure is provided completely outside the ground contact unit.

The shutdown device, which can be controlled by the monitoring circuit, is activated in particular when the monitoring circuit has a misalignment at least one of the contact switches detects, i.e. when one of the main contacts is in a closed position, although it should be in the open position, since the main contact belongs to a contact switch that is assigned to a power contact that is not contacted when the conductive connection is present . The shutdown device can then switch off at least the ground contact unit or the entire charging infrastructure, so that a freely accessible power contact, i.e. a non-contacted power contact, is not unintentionally assigned to a potential position, i.e. a voltage is present. The switch-off device can therefore be designed in such a way that an existing potential is completely switched off. Alternatively, the switch-off device can also lower the potential level to a non-critical level, which also corresponds to a switch-off in the sense of the invention, since no charging current flows. This means that the shutdown device does not necessarily have to completely (galvanically) disconnect the ground contact unit. In any case, protection against contact is guaranteed.

The main contact and/or the monitoring contact of the contact switch can be a switch that has an open position and a closed position. In this respect, the main contact or the monitoring contact is designed as an on or off switch. This means that the main contact or the monitoring contact can be adjusted between an open position and a closed position. The advantage if the main contact is designed as a switch with an open position and a closed position is, among other things, that the main contact cannot weld when opened if it moves from its closed position, in which the charging current flows via the main contact a second position passes, which does not correspond to an open position, but to a closed position with a different counterpart, for example ground. When opening, an arc can be generated, which would then ensure that the main contact is welded in the second (closed) position, so that the main contact and thus the entire contact switch could no longer be adjusted. This is effectively prevented if at least the main contact is designed as a switch that has an open position and a closed position.

However, it can also be provided that the main contact and/or the monitoring contact can be switched back and forth between two or more different, closed positions.

In any case, the main contact and the monitoring contact are galvanically isolated from each other, so that a common (closed) circuit is not formed across the two contacts, i.e. the main contact and the monitoring contact. The two contacts are therefore not used to provide a charging functionality in one switching position of the contact switch and a sensor functionality or similar in the other switching position of the contact switch. Rather, the main contact and the monitoring contact are assigned to two independent circuits that are galvanically isolated from each other.

In principle, monitoring can take place during the charging process, but also before a charging process and/or after a charging process, in particular in connection with a self-test. Furthermore, monitoring can take place at cyclical intervals.

If a faulty or incorrect switching position is detected, a warning can be issued, for example a visual warning, an acoustic warning and/or a warning by means of a remote signaling contact. It can also be provided that charging is not possible, i.e. no charging process can be started, if a faulty or incorrect switching position was detected during the check.

One aspect provides that the contact switches are designed in such a way that the switching positions of the main contact and the monitoring contact are mutually dependent. This is also known as the alternating principle, which is characteristic of a mirror contact. As soon as the main contact changes from the open position to the closed position, the monitoring contact simultaneously changes from the closed to the open position, so that the two positions of the main contact and the monitoring contact are mutually dependent. Due to the mechanical coupling of the main contact and the monitoring contact, it is ensured that the main contact and the monitoring contact cannot be in the open or closed position at the same time. This ensures reliable monitoring of the contact switch and thus of the main contact, which is live when closed.

In addition, the mechanical coupling is such that the monitoring contact is only closed when the main contact, designed as a relay, is open sufficiently wide, i.e. the isolating distance is present.

Another aspect provides that the main contact is designed as a NO contact, i.e. a normally open contact (NO), and the monitoring contact is designed as an NC contact det, i.e. a normally closed contact (“normally closed” - NC). This means that the contact switch has an initial position in which no current can flow via the main contact, which is designed as a relay, since the main contact is designed as a NO contact. At the same time, the monitoring contact is closed in the initial position, so that the monitoring circuit can determine that a monitoring current or a monitoring signal can run via the corresponding monitoring contact since there is no interruption.

According to a further aspect, the monitoring circuit controls the shutdown device to change its state if the monitoring circuit detects at least one incorrect switching position of the monitoring contacts of the contact switches. As soon as only a single monitoring contact of the contact switch assumes an incorrect or undefined switching position, the monitoring circuit controls the shutdown device to change its state. In this case, the ground contact unit or the entire charging infrastructure can be switched off. However, it can also be provided that the performance is reduced to a non-critical level. In this respect, the shutdown device can be a power control that is controlled accordingly by the monitoring circuit.

In particular, the incorrect switching position of the monitoring contact corresponds to the open switching position of the monitoring contact. The open switching position of the monitoring contact results in the main contact coupled to the corresponding monitoring contact being closed, whereby a current can flow via the contact switch to the power contact. This would mean that the assigned power contact is at a corresponding potential, which is undesirable if the switching position is incorrect. For this reason, the open switching position of the monitoring contact, which corresponds to the closed switching position of the assigned main contact, corresponds to the wrong switching position.

According to one embodiment, the shutdown device comprises a main switch. The main switch can also be referred to as a contactor, which ensures galvanic isolation when it is opened, in particular where all power contacts are galvanically isolated and not just the power contact whose assigned contact switch has an incorrect switching position, which has been detected accordingly. If the monitoring circuit detects an incorrect or undefined switching position, the shutdown device comprising the main switch can carry out a galvanic isolation, whereby all power contacts are switched potential-free.

In particular, the monitoring circuit is therefore set up to open the main switch in order to establish galvanic isolation via the main switch. This ensures a particularly high level of safety, as all power contacts are switched potential-free at the same time, so that there is no potential at any of the power contacts, which means that there is complete protection against contact. Any charging process would be interrupted.

According to a further embodiment, it can be provided that the shutdown device includes an electronic power control. The electronic power control is intended to regulate the corresponding potential down to a non-critical level so that contact is possible. In other words, the monitoring circuit can be set up to control the electronic power control and limit the applied voltage to a non-critical value. The non-critical value can be a voltage that is harmless, in particular a voltage below 25 V AC, i.e. 25 Vac, or 60 V DC, i.e. 60 Vdc.

The monitoring circuit can comprise at least a first sub-circuit that is integrated in the ground contact unit, wherein the first sub-circuit outputs at least one output signal of the ground contact unit to a second sub-circuit, which is provided in a monitoring unit designed separately from the ground contact unit. This results in a functional separation of the monitoring, since the monitoring circuit comprises several subcircuits. The at least one output signal can be a single output signal, with the ground contact unit transmitting its status to the separately designed monitoring unit. The state of the ground contact unit can be a binary signal, which corresponds, for example, to the states “okay” or “not okay”. The monitoring unit, in particular the second sub-circuit, is therefore set up to evaluate this output signal from the ground contact unit and to initiate measures, namely to activate the switch-off device accordingly.

In addition, it can also be provided that the first subcircuit transmits several output signals, in particular one output signal for each monitored contact switch. The multiple output signals are then sent by the separately designed monitoring unit, for example on a server or a Computing unit with higher computing power is provided, evaluated.

In particular, the second subcircuit of the monitoring circuit is set up to control the shutdown device. Depending on the at least one output signal that the second sub-circuit receives from the first sub-circuit, the second sub-circuit can then control the shutdown device after the second sub-circuit has evaluated the at least one output signal.

The shutdown device can in particular be part of a higher-level system, for example in the case of a parking garage of a building system such as a power supply system.

In addition, each contact switch can be assigned a control circuit, via which the contact switch is controlled accordingly. The control circuit can include a coil driver, which is in particular designed to be redundant. This means that the coil driver has at least one coil that has a first coil end and a second coil end. The two coil ends can be connected to an associated driver circuit, in particular a high-side driver and a low-side driver. This ensures that control is possible even if one of the drivers fails.

• - 1 eine schematische Übersicht eines Fahrzeugbatterieladesystems, das eine erfindungsgemäße elektrische Ladeinfrastruktur sowie ein Fahrzeug mit einer Fahrzeugkontakteinheit umfasst,
• - 2 eine schematische Draufsicht auf eine Bodenkontakteinheit einer erfindungsgemäßen elektrischen Ladeinfrastruktur,
• - 3 eine schematische Darstellung der elektrischen Verschaltung der Leistungskontakte der Bodenkontakteinheit gemäß 2, und
• - 4 eine schematische Übersicht über einen Ablauf, der ein Verfahren zum Überprüfen einer Bodenkontakteinheit einer elektrischen Ladeinfrastruktur umfasst.

Further advantages and properties of the invention result from the following description and the drawings to which reference is made. Shown in the drawings:

• - 1 a schematic overview of a vehicle battery charging system, which includes an electrical charging infrastructure according to the invention and a vehicle with a vehicle contact unit,
• - 2 a schematic top view of a ground contact unit of an electrical charging infrastructure according to the invention,
• - 3 a schematic representation of the electrical connection of the power contacts of the ground contact unit 2 , and
• - 4 a schematic overview of a process that includes a method for checking a ground contact unit of an electrical charging infrastructure.

In 1 a vehicle battery charging system 10 is shown, which shows an electrical charging infrastructure 12 and an at least partially electrically operated vehicle 14, which has a vehicle contact unit 16 which can establish a conductive connection with a ground contact unit 18 of the electrical charging infrastructure 12 in order to provide a battery (not shown here). Vehicle 14 to load.

The electrical charging infrastructure 12 has a monitoring circuit 20 and a shutdown device 22, which can be completely integrated in the ground contact unit 18. Alternatively, the monitoring circuit 20 can be arranged partly in the ground contact unit 18 and partly in a monitoring unit 24 which is designed separately from the ground contact unit 18. Furthermore, it can be provided that the monitoring circuit 20 and the shutdown device 22 are both arranged completely in the separately designed monitoring unit 24.

The separately designed monitoring unit 24 is therefore optional, which is why it is included 1 is shown in dashed lines. Likewise, the monitoring circuit 20 and the shutdown device 22 are shown in dashed lines, since their respective positions can be different depending on the embodiment.

In any case, the separately designed monitoring unit 24 would be electrically connected to the ground contact unit 18, as shown in FIG 1 is indicated.

In this respect, the electrical charging infrastructure 12 includes a checking system 25 with which checks can be carried out, as will be explained below.

In 2 the ground contact unit 18 is shown in a top view according to an embodiment variant.

The ground contact unit 18 has a plate-shaped base body 26 which has a loading surface 28 which is exposed before the conductive connection is established. In other words, the loading area 28 is therefore an exposed loading area when the contact between the ground contact unit 18 and the vehicle contact unit 16 is established.

However, the loading area 28 can in principle be covered by a cover (not shown here) when not in use, so that the loading area 28 is protected from environmental influences. The corresponding cover can be removed manually or automatically, making the loading area 28 freely accessible.

Several contacts 30 are provided on the loading surface 28, which can be different types of contacts.

In any case, the contacts 30 include, among other things, power contacts 32, which are used to charge the battery of the vehicle 14 by assigning the corresponding power contacts 32 to a potential position 34.

In the embodiment shown, the ground contact unit 18 is designed as a three-phase ground contact unit, which means that the individual power contacts 32 can be assigned to the phases L1, L2 and L3 as well as a neutral phase N, which is also referred to as the neutral conductor. These are therefore the corresponding potential levels N, P1, P2 and P3.

In addition to the power contacts 32, the contacts 30 include at least one protective conductor contact 35, i.e. a PE contact, with several protective conductor contacts 35 being provided in the embodiment shown, which are arranged separately and insulated from the power contacts 32 on the loading area 28.

Alternatively to in 2 In the embodiment shown, the ground contact unit 18 can have a continuous protective conductor level, which therefore essentially corresponds to the area of the base body 26 or the base area of the loading area 28. The individual power contacts 32 can then break through the corresponding protective conductor layer, with the power contacts 32 each being insulated from the protective conductor level, for example by annular sections.

In addition, the contacts 30 can also include at least one control contact 36, which is used to carry out a contact check.

In the embodiment shown, several control contacts 36 are provided, which have only been shown as examples. In principle, it can be determined via the control contacts 36 whether the vehicle contact unit 16 has contacted the ground contact unit 18.

In particular, the contacts 30 are basically distributed on the loading area 28 and arranged relative to one another in such a way that at least two control contacts 36 lie in a contacting area of the loading area 28, which is covered by the vehicle contact unit 16 when the conductive connection is established. The two control contacts 36 in the contact area can also be used to determine the orientation in which the ground contact unit 18 was contacted.

By knowing the geometry of the vehicle contact unit 16, it can also be determined which contacts 30 have been contacted, i.e. which of the contacts 30 belongs to the subset of the contacted contacts 30 that are in the contacting area of the loading area 28.

Out of 3 It can also be seen that the power contacts 32, which are assigned to the four different potential levels, namely the phases L1, L2, L3 and the neutral phase N, are each assigned to the corresponding potential level 34 via a contact switch 38.

The contact switches 38 are therefore connected in series with the power contacts 32, as shown 3 can be seen.

The contact switches 38 are each designed as mirror contacts, so that the contact switches 38 have a main contact 40 and a monitoring contact 42. Due to the design as mirror contacts, it is ensured that the main contact 40, which functions as a relay, is mechanically coupled to the monitoring contact 42, so that the respective switching positions of the main contact 40 and the monitoring contact 42 are mutually dependent or dependent on one another. However, the main contact 40 and the monitoring contact 42 are galvanically isolated from one another, so that both contacts 40, 42 are not assigned to a common circuit. Rather, both contacts 40, 42 are assigned to different circuits that are independent of one another and are also galvanically isolated from one another.

In this respect, there is no switching position of the contact switch 38 in which a closed circuit is formed in which both the main contact 40 and the monitoring contact 42 are integrated, so that a current could flow via both contacts 40, 42 of the contact switch 38.

The main contact is 40, as in 3 shown, is designed as a normally open contact, i.e. a NO contact, whereas the monitoring contact 42 is designed as a normally closed contact, i.e. an NC contact.

In 3 The starting position of the contact switches 38 is therefore shown, since the contact switches 38 are each in a corresponding switching position in which the main contacts 40 are open, so that no current flow to the power contacts 32 is possible. In other words, the power contacts 32 are not connected to any potential layer 34, which ensures protection against contact.

The corresponding contact protection can be monitored by means of the charging infrastructure 12 by the monitoring circuit 20, among other things rem the respective switching position of the monitoring contacts 42 of the corresponding contact switches 38 is monitored.

The monitoring takes place at least with the contact switches 38, which are assigned to power contacts 32, which are not contacted when there is a conductive connection between the ground contact unit 18 and the vehicle contact unit 16, i.e. with power contacts 32, which are not part of the subset of the several contacts 30 of the ground contact unit 18 belong who have been contacted.

The monitoring circuit 20 controls the shutdown device 22 if the monitoring circuit 20 determines that there is an incorrect switching position in one of the monitoring contacts 42, which has the result that one of the main contacts 40 also has an incorrect switching position, since the monitoring contacts 42 and the main contacts 40 are mechanically coupled to each other.

The incorrect switching position corresponds to an open switching position of the monitoring contact 42, which is accompanied by a closed switching position of the assigned main contact 40, which would mean that a freely accessible power contact 32 would be assigned to a potential position 34, although this is not desired since the corresponding power contact 32 is exposed.

The shutdown device 22 changes its state due to the control by the monitoring circuit 20, which can be accompanied by a complete shutdown or a complete separation. In other words, the shutdown device 22 can be designed in such a way that a galvanic isolation of all power contacts 32 is carried out, whereby all power contacts 32 would be switched potential-free.

In this respect, the shutdown device 22 can include a main switch 44 or a contactor, which carries out the corresponding galvanic isolation.

If the shutdown device 22 is integrated in the ground contact unit 18, two switching elements are provided in a current path within the ground contact unit 18, which are connected in series, namely the respective contact switches 38 and the main switch 44.

Alternatively, the switch-off device 22 can include an electronic power control 46, which is intended to correspondingly reduce the voltage assigned to the potential level 34, so that the applied voltage is limited to a non-critical value, thereby ensuring contact protection. In other words, the respective power contact 32, which is coupled to the incorrectly closed main contact 40 of the contact switch 38, has such a low voltage that there is no danger.

In 1 It has already been shown that both the monitoring circuit 20 and the shutdown device 22 can be arranged partly in the ground contact unit 18 and partly in the separately designed monitoring unit 24.

If the monitoring circuit 20 comprises two sub-circuits, it can be provided that the first sub-circuit is integrated in the ground contact unit 18 and outputs at least one output signal of the ground contact unit 18 to the second sub-circuit of the monitoring circuit 20, which is integrated in the separately designed monitoring unit 24.

The at least one output signal can transmit the state of the entire ground contact unit 18, for example in the form of a binary signal, i.e. “ok” or “not ok”, whereby the monitoring circuit 20, in particular the second sub-circuit, then controls the shutdown device 22 accordingly, so that the shutdown device 22 changes its state.

With the help of the monitoring circuit 20, a continuous touch protection monitoring of the power contacts 32 takes place by continuously monitoring switching positions of the contact switches 38, which are assigned to power contacts 32 that do not belong to the subset of the contacted contacts 30.

In addition to this continuous contact protection monitoring, it can also be provided that continuous contact protection monitoring is carried out by continuously monitoring an existing contact of at least one contact 30, which belongs to the subset of the contacted contacts 30. This can be the control contact 36, a power contact 32 and/or one of the protective conductor contacts 35.

For corresponding monitoring, a signal, for example a high-frequency signal, can be fed in via one of the corresponding contacts 30, whereby an interruption of the corresponding signal would be detected if the conductive connection breaks off.

In principle, incorrect control of one of the contact switches 38 can be detected, for example caused by a problem with the (control) electronics and/or due to a software problem. Such a determination or monitoring is possible in particular during a charging process.

Out of 4 It also shows that in addition to the continuous touch protection monitoring, further checks take place, especially before a charging process is initiated.

To prepare for the charging process, a self-test of the power contacts 32 can first be carried out to ensure that the contact switches 38 of all power contacts 32 are open. This can be done at the beginning to ensure that the ground contact unit 18 is basically in a state to be able to carry out a charging process at all.

For this purpose, the positions of the contact switches 38 can be monitored by means of the monitoring circuit 20, in particular the monitoring contacts 42, as has already been described previously with regard to continuous touch protection monitoring.

In addition, the preparation phase includes a compatibility check, in which communication takes place between the ground contact unit 18 and the vehicle contact unit 16 of the vehicle in order to determine whether the two contact units 16, 18 can even carry out a charging process with one another. Corresponding signals can be exchanged with one another in order to determine whether the contact units 16, 18 are compatible with one another.

Subsequently, positioning can take place during the preparation phase, in which the vehicle 14 is positioned via the ground contact unit 18 or in relation thereto, for example by displaying corresponding signals to a driver of the vehicle 14 so that he can move the vehicle 14 as precisely as possible via the ground contact unit 18 parked, whereby a conductive connection can be established. This makes it possible to minimize the size of the ground contact unit 18.

The vehicle 14 or the vehicle contact unit 16 will then send a charging request to the electrical charging infrastructure 12, in particular the ground contact unit 18. The electrical charging infrastructure 12 processes the charging request accordingly. If the result is positive, this will be communicated to the vehicle 14 or the vehicle contact unit 16, whereupon the charging process could be initiated.

For this purpose, the conductive connection between the vehicle contact unit 16 and the ground contact unit 18 is first established by moving at least one component of the vehicle contact unit 16 in the direction of the ground contact unit 18, as a result of which this comes into contact with areas on the loading surface 28 of the ground contact unit 18, so that at least a subset of the several contacts 30 of the ground contact unit 18 are contacted.

In order to determine this, the contact check is carried out, in which it is determined whether contacts 30 of the ground contact unit 18 are contacted. In addition, it can be determined which of the corresponding contacts 30 are contacted by switching them through individually and/or in groups.

For this purpose, high-frequency signals can be provided, which are routed via the power contacts 32. Alternatively, it can be provided that this takes place via the control contacts 36. The control contacts 36 can carry different signals, which means that, in addition to simply determining which contacts 30 are occupied, it can also be determined what the contacting orientation of the vehicle contact unit 16 is in relation to the ground contact unit 18.

Depending on the contact check carried out, the power contacts 32 could then be assigned to specific potential levels 34.

During the checking phase, however, a protective conductor check still takes place, in which a test current is passed over at least one contact 30 of the several contacts 30 in order to determine a contact quality of the existing conductive connection between the vehicle contact unit 16 and the ground contact unit 18.

For this purpose, the vehicle 14 can include a current generator or a signal generator, which provides the test current, which is conducted via one of the contacts of the vehicle contact unit to a contact 30 of the contacts 30 of the ground contact unit 18 coupled thereto.

For example, one of the power contacts 32 can be used, which is coupled to a corresponding power contact of the vehicle contact unit 16, the corresponding power contact 32 of the ground contact unit 18 being switched to the protective conductor level, which corresponds to the level of the protective conductor contact 35. For this purpose, a relay can be provided, via which the corresponding contact 30 is connected to the protective conductor level.

A resistance can then be measured to determine the contact quality. The measured resistance should not exceed a resistance value of 0.1 Ω, so that a protective conductor resistance threshold of 0.1 Ω is provided. The test current used should have a current strength of at least 200 mA.

Alternatively, it can also be provided that the test current is provided by the ground contact unit 18.

A further step provides that an insulation check is carried out during the check in order to determine that there are no leakage currents or the like between contacts 30 or other areas of the ground contact unit 18.

In principle, the insulation test can be carried out between two contacts 30 by applying a test voltage and measuring an insulation resistance, which is compared with a predetermined insulation resistance threshold. For example, the test voltage is at least 500 V. The insulation resistance threshold is, for example, 0.25 MΩ.

The two contacts 30 that are used for the insulation check can be adjacent contacts on the loading surface 28, in particular two contacts 30 of the subset of the contacts 30 that are contacted when the conductive connection is present. An (unintentional) conductive connection is most likely to occur between adjacent contacts 30, for example via an object, dirt or moisture. In particular, the insulation check is carried out between two power contacts 32. Alternatively or additionally, it can be provided that the insulation check is carried out between at least one line contact 32 and the at least one protective conductor contact 35. The insulation check can also be carried out between at least one line contact 32 and the control contact 35.

During the insulation check, the insulation from a contact 30 of the subset to a point on the loading surface 28 of the base body 26 can also be measured.

In principle, it can be provided that the insulation check is only carried out if it has previously been determined that at least a subset of the several contacts 30 are contacted at all, i.e. there is a conductive connection.

In addition, the protective conductor check can only be carried out if it has previously been determined that there is a conductive connection, i.e. at least the subset of the several contacts 30 is contacted. In addition, the protective conductor check can only be carried out if the insulation check has been carried out successfully beforehand.

After the verification has been carried out and all verification steps have been successfully completed, the loading process can begin.

As already explained previously, the power contacts 32, which do not belong to the subset of the contacted contacts 30, have already been switched potential-free, which was also checked during the self-test during preparation.

In this respect, only the power contacts 32 of the corresponding potential position 34, which belong to the subset of the contacted contacts 30, are switched on.

A charging current then flows from the ground contact unit 18 into the battery of the vehicle 14 via the vehicle contact unit 16, which has formed the conductive connection with the ground contact unit 18, whereby the battery is charged accordingly.

Continuous touch protection monitoring takes place during the charging process, as already explained. This determines whether only the contacted power contacts 32 are actually connected to a corresponding potential position 34 or whether the existing contacting does not break off during the charging process by continuously monitoring a contact 30 of the subset of the contacted contacts, for example the control contact 36.

If it is determined that protection against contact is no longer guaranteed, the shutdown device 22 is controlled by the monitoring circuit 20, whereby either the main switch 44 is opened in order to carry out galvanic isolation and/or the electronic power control 46 regulates the corresponding potential down until a uncritical voltage value has been reached. The non-critical value can be a voltage that is harmless, in particular a voltage below 25 V AC, i.e. 25 Vac, or 60 V DC, i.e. 60 Vdc.

After the charging process has been completed, the conductive connection between the vehicle contact unit 16 and the ground contact unit 18 is separated.

For this purpose, the previously connected power contacts 32, which belong to the subset, are first switched potential-free by controlling the corresponding contact switches 38. In addition, the shutdown device 22 can also be controlled accordingly, for example to carry out galvanic isolation via the main switch 44. This creates redundancy. In addition, it can be checked again whether the power contacts 32 are all potential-free by monitoring the assigned monitoring contacts 42 via the monitoring circuit 20.

The conductive connection is then released by disengaging the vehicle contact unit 16 so that there is no longer any contact with the ground contact unit 18. The vehicle 14 can then leave the electrical charging infrastructure 12.

Finally, a new self-test can be carried out by determining whether all power contacts 32 are in their potential-free state, i.e. whether the assigned contact switches 38 are all in the non-current-carrying state, which is present when the corresponding main contacts 40 are opened or the monitoring contacts 42 are closed.

In principle, the self-test can of course also be carried out at other times. Self-tests can therefore be carried out at several times, for example cyclically, in order to continuously check the readiness of the electrical charging infrastructure 12, in particular that of the ground contact unit 18.

In this respect, it is ensured that the vehicle 14 can be efficiently charged electrically by making a conductive connection. At the same time, appropriate safety precautions are taken by checking whether the ground contact unit 18 is in a state that is suitable for a charging process.

The in 4 The process shown and the associated method can in principle be carried out by the electrical charging infrastructure 12, which is set up accordingly.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2019052962 A1 [0003, 0004]

Claims (11)

Electrical charging infrastructure (12) for establishing a conductive connection to a vehicle contact unit (16), wherein the charging infrastructure (12) has a ground contact unit (18) which has a plate-shaped base body (26) and a plurality of contacts (30) which are arranged on a loading surface (28) of the base body (26) on which the vehicle contact unit (16) can come to the facility, wherein the plurality of contacts (30) comprise at least power contacts (32) which are assigned to at least one potential layer, wherein the power contacts (32) are each connected in series to a contact switch (38), wherein the contact switches (38) are each designed as mirror contacts, so that each contact switch (38) comprises a main contact (40) and a monitoring contact (42), which are mechanically coupled but are galvanically isolated from one another, wherein the charging infrastructure (12) has a monitoring circuit (20) which is set up to monitor at least the respective switching position of the monitoring contacts (42) of the contact switches (38), which are assigned to power contacts (32) which are not contacted when there is a conductive connection are and wherein the monitoring circuit (20) is set up to control a shutdown device (22). Electrical charging infrastructure Claim 1 , characterized in that the contact switches (38) are designed such that the switching positions of the main contact (40) and the monitoring contact (42) are mutually dependent. Electrical charging infrastructure Claim 1 or 2 , characterized in that the main contact (40) is designed as a NO contact and the monitoring contact (42) is designed as an NC contact. Electrical charging infrastructure according to one of the preceding claims, characterized in that the monitoring circuit (20) controls the shutdown device (22) to change its state if the monitoring circuit (20) detects at least one incorrect switching position of the monitoring contacts (42) of the contact switches (38). . Electrical charging infrastructure Claim 4 , characterized in that the incorrect switching position of the monitoring contact (42) corresponds to the open switching position of the monitoring contact (42). Electrical charging infrastructure according to one of the preceding claims, characterized in that the shutdown device (22) comprises a main switch (40). Electrical charging infrastructure Claim 6 , characterized in that the monitoring circuit (20) is set up to open the main switch (40) in order to establish galvanic isolation via the main switch (40). Electrical charging infrastructure according to one of the preceding claims, characterized in that the shutdown device (22) comprises an electronic power control (46). Electrical charging infrastructure Claim 8 , characterized in that the monitoring circuit (20) is set up to control the electronic power control and to limit the applied voltage to a non-critical value. Electrical charging infrastructure according to one of the preceding claims, characterized in that the monitoring circuit (20) comprises at least a first sub-circuit which is integrated in the ground contact unit (18), wherein the first sub-circuit outputs at least one output signal of the ground contact unit (18) to a second sub-circuit which is provided in a monitoring unit (24) designed separately from the ground contact unit (18). Electrical charging infrastructure Claim 10 , characterized in that the second sub-circuit of the monitoring circuit (20) is set up to control the shutdown device (22).

Images