DE102019214938A1 - Charging system for charging an electrical energy storage device in a road vehicle - Google Patents

Abstract

The invention relates to a charging system (4) for charging an electrical energy store (2) of a road vehicle (1), which has a current collector (8) with at least one for each contact pole (6P, 6N) for feeding energy from a two-pole overhead contact line system with a contact wire (7) raisable and lowerable contact strip (9) for making electrical contact with the contact wire (7) of this contact pole (6P, 6N). The charging system (4) comprises a charging station (3) with a charging contact (12) for each contact pole (6P, 6N), which is located above the at least one contact strip (9) assigned to this contact pole (6P, 6N) of the road vehicle in a charging position. 1) is arranged, and with a grounding contact (13) which is arranged above and laterally spaced from the contact strips (9) of the road vehicle (1) located in the loading position and is grounded via a protective conductor (17). The current collector (8) has two detection contacts (15) that are insulated from the contact strips (9) and against an electrical ground potential (P16) of the vehicle frame (16) and connected to one another with high resistance, which when the contact is closed between the contact strips (9) and the charging contacts ( 12) are bridged by the earthing contact (13). A bridging of the detection contacts (15) can be detected by the grounding contact (13) by means of a measuring device (22). One of the detection contacts (15) is connected to the ground potential (P16) in a separable manner by a ground line (24) having a switching element (23).

Description

The invention relates to a charging system for charging an electrical energy store of a road vehicle, which comprises a current collector with at least one lifting and lowering contact strip for making electrical contact with the contact wire of this contact pole for feeding energy from a two-pole catenary system with a contact wire for each contact pole.

In the case of electrically or hybrid-electrically driven road vehicles, in particular heavy commercial vehicles, it is, for example, from the laid-open specification DE 10 2017 203 046 A1 known to charge the energy store while driving via an energy supply from a two-pole overhead line system by means of a vehicle-mounted pantograph. The current collector comprises a pantograph-like frame, which carries a rocker with two contact strips for each contact pole. During the journey, the contact strips of each contact pole are in sliding contact with the contact wires assigned to the respective contact pole, so that electrical energy can be fed in both directly for the traction drive and for charging the energy storage device, so that sections of the route without overhead line systems can also be covered with electrical energy. At the moment of power consumption from the overhead line system, a few 100 kW of power can be transferred.

To avoid dangerous contact voltages on the vehicle frame is from the patent EP 3 036 127 B1 a vehicle known with a protection system. It has a first protection level, which is formed by an electrically isolated installation of at least the traction drive on the vehicle frame, and a second protection level with higher security, which is also formed by a galvanically isolating DC voltage converter connected between the pantograph and the traction drive. By means of a switching element, the protection system can be switched between the first and second protection stages by optionally connecting or bridging the DC voltage converter. The protection system satisfies different safety requirements in different operating states of the vehicle, which are characterized by different possible interactions between people and vehicle. A first operating state - for example at low speeds or when the vehicle is at a standstill - requires a high level of safety, since an insulation fault can lead to dangerous body currents from touching the vehicle. The connected DC voltage converter separates the contact wire potential applied to the contact strips from the ground potential of the vehicle frame. An inexpensive DC / DC converter with low power transfer is used, as this is only switched on when the vehicle is at a standstill and at low speeds. In a second operating state - at a higher driving speed of the vehicle - it is assumed that people with reference to ground no longer touch the vehicle. In this case, the DC voltage converter is bridged and the contact wire potential is switched directly to the drive control of the vehicle, if necessary via a non-electrically isolating DC voltage converter with a higher transmission power.

The invention is therefore based on the object of providing a charging system of the type mentioned at the outset, with which high charging powers can be transmitted for fast charging of the energy storage device when the battery is stationary and which nevertheless offers sufficient personal protection from electrical contact voltages.

The object is achieved by a charging system with the features specified in claim 1. Accordingly, the charging system is suitable and provided for charging an electrical energy store of a road vehicle when it is stationary. The road vehicle, for example a heavy commercial vehicle, includes a current collector with at least one lifting and lowering contact strip for making electrical contact with the contact wire of this contact pole for feeding energy from a two-pole catenary system, which has a contact wire for each contact pole. According to the invention, the charging system comprises a charging station with a charging contact for each contact pole, which is arranged above the at least one sliding strip associated with this contact pole of a road vehicle in a charging position. The charging station also has an earthing contact which is arranged above and laterally spaced from the contact strips of the road vehicle in the charging position and which is earthed via a protective conductor. Charging contact and grounding contact can be arranged, for example, on a charging mast of the charging station. The current collector of the road vehicle has two detection contacts that are insulated from the contact strips and from an electrical ground potential of the vehicle frame and connected to one another at high resistance. The detection elements can, for example, be designed as metal brackets which are arranged between the sliding strips of the two contact poles. If the contact between the sliding strips and the charging contacts is closed, the grounding contact bypasses the detection elements. The bridging can be detected by means of a measuring device. The measuring device can have a resistor network with evaluation electronics that register a bridging as a change in a voltage value. Since the detection cost files in In exceptional cases, contact wire potential can come into play, this and the measuring device are isolated from the ground potential. In this case, one of the detection contacts is connected to the ground potential in a separable manner by a ground line having a switching element. The ground line can be designed as a flexible, sufficiently current-carrying cable. Since only one of the two detection contacts is connected to the vehicle frame, this does not lead to any change in the measured value in the resistor network and the associated evaluation electronics.

The charging station with two charging contacts and one grounding contact is of central importance for the invention. As a result, the vehicle frame and electrically conductively connected vehicle parts, such as the driver's cab or other vehicle superstructures, are grounded via the grounding contact of the charging station during the charging process, and this grounding connection is monitored. The well-known low-power DC voltage converter with galvanic isolation can be dispensed with. It is also possible to recharge electrical energy outside of streets with overhead line systems if charging stations are installed in parking lots, in vehicle depots or at transshipment points for transported goods.

In an advantageous embodiment of the charging system according to the invention, the ground line can be separated by a further switching element. The further switching element offers redundancy to the switching element, the ground potential being isolated from the detection contacts, both of which are protected against initial faults.

In a further advantageous embodiment of the charging system according to the invention, the switching element and the further switching element are open on the overhead line system during driving and can only be closed when a parking brake of the road vehicle is actuated when the vehicle is at a standstill. For standstill charging, the driver must first have applied the parking brake, then he closes the redundant switches for standstill charging, which connects the detection contacts to the ground potential of the vehicle frame. If the parking brake is not properly activated, this is recognized as an error.

In a further advantageous embodiment of the charging system according to the invention, the grounding contact and the detection contacts are arranged in such a way that when the sliding strips are lifted, contact is first made between the grounding contact and the detection contacts and then between the sliding strips and the charging contacts. After the road vehicle has been parked in the charging position, the pantograph is set up, with the charging contacts of the charging station not yet carrying any charging voltage. With the contact strips, the detection contacts are lifted, which first touch the ground contact before the contact strips make contact with the charging contacts. If both detection contacts touch the ground contact, this is detected via the resistor network, the measured voltage value changes and a corresponding signal can be transmitted.

In a further advantageous embodiment of the charging system according to the invention, the current path between the current collector and a potential separation point, which is at contact wire potential in the event of contact, has double insulation with two insulation layers and an isolated intermediate ground, the ground potential being separably connected to an intermediate potential of the intermediate ground via a connecting line having another switching element . In order to be able to ground the intermediate ground, it is connected to ground potential by closing the other switching element via the connecting line.

In a further advantageous exemplary embodiment of the charging system according to the invention, the vehicle has a monitoring unit for monitoring an insulation fault between ground potential and intermediate potential. The monitoring unit measures the resistance between the ground potential of the vehicle frame and the intermediate potential of the intermediate ground and initiates the lowering of the pantograph in the event of an insulation fault. During the charging process, if the ground and intermediate potential are short-circuited, it is used to check the low-resistance connection between these potentials.

In a further advantageous exemplary embodiment of the charging system according to the invention, the vehicle has a detection device for detecting that a contact has been made between the charging contacts and the sliding strips.

The correct contact closure of the contact strips to the two charging contacts plus and minus is determined with the help of a sensor system that can be formed, for example, by two displacement sensors that measure the deflection on the two spring bearings of a rocker bearing the contact strips. The lateral position of the contact point can be deduced from the two deflections and thus it can be determined whether and where the charging contacts are resting on the contact strips. If the road vehicle was placed incorrectly and, for example, a charging contact also touches one of the detection contacts, this is detected by the monitoring unit and the pantograph is then lowered and an error message is triggered in the vehicle. The position of the road vehicle must then be corrected. To avoid overheating at high charging currents at standstill To avoid the contact strips, make sure that there is a large contact area between the charging contacts and the contact strips. This can be achieved, for example, by increasing the contact points or by flexibly adapting the shape of the charging contacts to the contact strip surface.

In a further advantageous embodiment of the charging system according to the invention, the charging station and vehicle are connected via a wireless communication system via which a release signal can be transmitted to the charging station, which triggers the closing of contactors to apply the charging voltage to the charging contacts. In order to be able to carry out a safe charging process, the charging voltage is only applied to the charging contacts by the charging station when the charging station receives a release signal from the road vehicle. This ensures that the parts of the vehicle that are at risk of contact and which are at ground potential of the road vehicle are grounded via the grounding contact of the charging station.

• 1 ein erfindungsgemäßes Ladesystem mit einem in einer Ladestation positionierten Straßenfahrzeug,
• 2 ein Schutzsystem eines Straßenfahrzeugs im Oberleitungsbetrieb und
• 3 das Schutzsystem aus 2 im Ladebetrieb des Straßenfahrzeugs

Further properties and advantages of the invention emerge from the following description of a specific exemplary embodiment with reference to the drawings, in which

• 1 a charging system according to the invention with a road vehicle positioned in a charging station,
• 2 a protection system of a road vehicle in overhead contact line operation and
• 3 the protection system off 2 in the loading mode of the road vehicle

are illustrated schematically.

According to 1 is a road vehicle 1 to charge its electrical energy storage 2 in a charging station 3 of the charging system according to the invention 4th at a loading position on a lane 5 switched off. The road vehicle 1 , for example a heavy commercial vehicle, includes for energy supply from a two-pole overhead line system, which per contact pole 6P , 6N a contact wire 7th has a pantograph 8th on. The contact wires 7th the catenary system, which is known per se and is not shown in detail, is above an electrified lane of the roadway 5 arranged while the charging station 4th also apart from it in a parking lot, in a vehicle depot or at a goods transfer point for the road vehicle 1 can be installed. The pantograph 8th points per contact pole 6P , 6N a two sanding strips 9 load-bearing seesaws 10 on that of a pantograph-like frame 11 be worn. By setting up and putting down the frame 11 are the contact strips 9 Can be raised and lowered for electrical contact with the contact wires 7th to be able to establish and interrupt.

The charging station 3 includes per contact pole 6P , 6N a charging contact 12th as well as a ground contact 13th , for example between the charging contacts 13th can be arranged. The charging contacts 12th and the ground contact 13th are on a loading mast 14th so above the roadway 5 arranged that a road vehicle in the loading position 1 by setting up his pantograph 8th one electrical contact closure per contact pole 6P , 6N between contact strips 9 and charging contacts 12th can produce. The pantograph 8th has two detection contacts 15th on, which are connected with each other with high resistance and against the contact strips 9 and against an electrical ground potential P16 of the vehicle frame 16 is isolated. The detection contacts 15th can for example be designed as a metal bracket and between the contact strips 9 of the two contact poles 6P , 6N be arranged. The ground contact 13th is like that on the loading mast 14th arranged that he was when setting up the pantograph 8th the two detection contacts 15th even before the contact between contact strips 9 and charging contacts 12th contacted and bridged. The ground contact 13th is via a protective conductor 17th grounded. The charging contacts 12th are via supply lines 18th with shooters 19th in one of the loading mast 14th assigned station building 20th coupled. In the station building 20th the supply voltage of the public power grid is connected to the contactors 19th on, which is filtered, transformed and rectified downstream of the charging contacts 12th is feedable.

When driving according to 2 exists between the contact strips 9 and the contact wires 7th electrical sliding contact, so that the contact strips 7th on contact wire potential P7 lie. The further current path from the contact strips 7th up to an electrical isolation point in the road vehicle 1 is with two layers of insulation and isolated intermediate ground 21 that is on an intermediate potential P21 against the vehicle frame 16 isolated. The detection contacts 15th are opposite the ground potential P16 isolated. A bridging of the detection contacts 15th is by means of a measuring device 22nd detectable, which has a resistor network with evaluation electronics and a bridging - for example, by an incorrectly contacted contact wire 7th - registered as a change in a voltage value. One of the two detection contacts 15th is through a switching element 23 having ground line 24 separable with the ground potential P16 connected. The ground line 24 can be designed as a flexible cable with sufficient current carrying capacity. The ground line 24 is preferably through a further switching element 25th separable. The further switching element 25th and the switching element 23 are redundant and secured against initial errors. The ground potential P16 is about a another switching element 26th having connecting line 27 separable with the intermediate mass 21 connected to the intermediate ground 21 to be able to ground. The switching element 23 and the further switching element 25th are open when the catenary system is in motion.

The road vehicle is stationary 1 quietly in the loading position, the driver applies a parking brake 28 . Only then can according to 3 the switching elements 23 , 24 , 26th are closed, whereby the detection contacts 15th with the ground potential P16 of the vehicle frame 16 get connected. Is the parking brake 28 not activated properly, this is recognized as an error. Now the sanding strips 9 and the detection contacts 15th raised until there is initially a contact closure between the ground contact 13th and detection contacts 15th and then further between the contact strips 9 and the charging contacts 12th he follows. The charging contacts 12th do not yet have charging voltage. If both detection contacts 15th the ground contact 13th touch, this is done by the measuring device 22nd detected and a corresponding signal can be transmitted. Likewise, a signal is transmitted when a detection device 29 a correct contact closure between the charging contacts 12th and the contact strips 9 for both contact poles 6P , 6N notices. The detection device 29 can be formed, for example, by two displacement sensors, which determine the deflection on the two spring bearings of the contact strips 9 measure up. The two deflections can be used to deduce the lateral position of the contact point and thus determine whether and where the charging contacts are 12th on the contact strips 9 rest. Became the road vehicle 1 placed incorrectly and touches, for example, one of the charging contacts 12th also one of the detection contacts 15th , this is done by the measuring device 22nd detected and then a lowering of the pantograph 8th and an error message in the road vehicle 1 triggered. The position of the road vehicle 1 must then be corrected.

The charging station 3 and the road vehicle 1 are through a wireless communication system 30th connected, via which a release signal is sent to the charging station 3 is transmittable. Receipt of the enable signal triggers the closing of the contactors 19th for applying the charging voltage to the charging contacts 12th out. This ensures that the P16 of the road vehicle 1 lying, touch-endangered vehicle parts via the grounding contact 13th the charging station 3 are grounded.

The vehicle has a monitoring unit 31 for monitoring an insulation fault between ground potential P16 and intermediate potential P21 on. It measures the resistance between the potentials P16 and P12 and directs the lowering of the pantograph in the event of an insulation fault 8th a. During the charging process, if the ground and intermediate potential are short-circuited, it is used to check the low-resistance connection between these potentials.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the 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.

Patent literature cited

• DE 102017203046 A1 [0002]
• EP 3036127 B1 [0003]

Claims (8)

Charging system (4) for charging an electrical energy storage device (2) of a road vehicle (1), which has a pantograph (8) with at least one that can be raised and lowered to feed energy from a two-pole catenary system with a contact wire (7) for each contact pole (6P, 6N) Sliding strip (9) for making electrical contact with the contact wire (7) of this contact pole (6P, 6N), characterized by - a charging station (3) with a charging contact (12) per contact pole (6P, 6N) which is above the at least one , this contact pole (6P, 6N) associated sliding strip (9) of the road vehicle (1) located in a loading position is arranged, and with a grounding contact (13) which is above and laterally spaced from the sliding strips (9) of the road vehicle located in the loading position (1) is arranged and grounded via a protective conductor (17), - the current collector (8) two against the contact strips (9) and against an electrical ground potential (P16) of the Fah rzeugrahmens (16) has isolated and high-resistance interconnected detection contacts (15), which are bridged when the contact between the sliding strips (9) and the charging contacts (12) by the grounding contact (13), - bridging of the detection contacts (15) by the Grounding contact (13) can be detected by means of a measuring device (22), and - one of the detection contacts (15) being connected to ground potential (P16) in a separable manner by a grounding line (24) having a switching element (23). Charging system (4) Claim 1 , wherein the ground line (24) can be separated by a further switching element (25). Charging system (4) Claim 2 , wherein the switching element (23) and the further switching element (25) are open when driving on the overhead line system and can only be closed when a parking brake (28) of the road vehicle (1) is actuated. Loading system (4) according to one of the Claims 1 to 3 , wherein the ground contact (13) and the detection contacts (15) are arranged in such a way that when the sliding strips (9) are lifted, first a contact connection between the grounding contact (13) and the detection contacts (15) and then between the sliding strips (9) and the Charging contacts (12) takes place. Loading system (4) according to one of the Claims 1 to 4th The current path between the pantograph (5) and a potential separation point, which is at contact wire potential (P7) in the event of contact, has double insulation with two insulation layers and an isolated intermediate ground (21), and the ground potential (P16) via a different switching element (26) Connecting line (27) is separably connected to an intermediate potential (P21) of the intermediate ground (21). Charging system (4) Claim 5 , wherein the road vehicle (1) has a monitoring unit (31) for monitoring an insulation fault between ground potential (P16) and intermediate potential (P12). Loading system (4) according to one of the Claims 1 to 6th , wherein the road vehicle (1) has a detection device (29) for detecting a contact closure between the charging contacts (12) and the sliding strips (9). Loading system (4) according to one of the Claims 1 to 7th , the charging station (3) and the road vehicle (1) being connected via a wireless communication system (30), via which a release signal can be transmitted to the charging station (3), which signals the closing of the contactors (19) to apply the charging voltage to the charging contacts ( 12) triggers.

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