Road vehicle having a current collector

Abstract

The invention relates to an electrically or hybrid-electrically driven road vehicle (10), in particular a lorry, comprising a current collector (12) for electrical power transfer by contacting contact wires (21), carrying an electrical contact-wire voltage, of an electrical overhead line system (20). In traction operation, power is supplied from the overhead line system (20) and, in recuperation operation, power is supplied back into the overhead line system (20). According to the invention, the road vehicle (10) comprises a measuring device (13) for detecting the current contact-wire voltage and a control device (14) connected thereto for activating and deactivating the power transfer. The control device (14) is designed to deactivate the supply of power if a lower threshold value of the contact-wire voltage is not met and to reactivate the supply of power if the lower threshold value is exceeded after a randomly selected activation delay has elapsed. A road vehicle (10) of this kind can be used to prevent traffic situations at risk of overload in a feed portion of the overhead line system (20).

Description

[0001] Description

[0002] Road vehicle with one pantograph

[0003] The invention relates to an electrically or hybrid-electrically powered road vehicle according to the preamble of patent claim 1.

[0004] Such a road vehicle, in particular a truck or a bus, comprises an electric or hybrid-electric traction drive. It further comprises a current collector for transmitting electrical power by contacting contact wires of an electrical overhead line system. The overhead line system installed on the trackside can be of two-pole design, i.e. it can have two contact wires designed as forward and return conductors, which run parallel to one another and above a lane of an electrified section of track. Trackside substations supply feed sections of the overhead line system with an electrical contact wire voltage. During traction operation, power is fed from the overhead line system into the road vehicle in order to supply the traction drive with energy and, if necessary, to charge an on-board energy storage device.In recuperation mode, power can also be fed back from the road vehicle into the overhead line system in order to transfer excess energy via the contact wires to the supply section being traveled on.

[0005] The contact wire voltage provided by the substation fluctuates around its nominal value depending on vehicle operation in a feeder section. The contact wire voltage drops with an increasing number of road vehicles traversing the feeder section in traction mode. In particular, heavily trafficked feeder sections with uphill road surfaces or with a clearing traffic jam pose challenges for the operator of the overhead line system with regard to load-dependent energy management. Various central approaches to solving this problem are known from the state of the art.

[0006] The international publication WO 2013 / 064447 A2 discloses a system for controlling the traffic of electrically powered vehicles which can be coupled to a roadside overhead line network for energy transfer while in motion. The overhead line network has separately supplied feed sections with adjustable load limits. Using forecasting tools, a load requirement in a feed section is determined from a recorded traffic and weather situation and from a road gradient using a forecast model which specifies the load capacity of a vehicle as a function of its total weight, speed and acceleration for different road gradients and weather situations. The forecast load requirement is evaluated with regard to the load limit of the feed section in order to select any necessary control interventions for influencing tools in the form of on-board devices installed in the vehicle.Using on-board equipment, instructions can be issued to vehicle drivers in the form of control interventions to reduce load pickup. With regard to a supply section at risk of overload, the control devices select between specifying a detour, a speed limit, an entry barrier, a starting instruction to clear traffic jams, and a request to switch from electric to fuel drive, to switch the load pickup from the overhead line network to an on-board energy storage device, or to feed energy from an on-board energy storage device back into the overhead line network.

[0007] From the European publication EP 3 756 931 A1 an energy supply system for non-track-bound, electrically powered vehicles on a section of a road network is known. It comprises an overhead line system with a contact line running above a lane of the section of track and with a substation for feeding the overhead line with electrical energy. The overhead line can be contacted by current collectors on the vehicles for power consumption. The overhead line system is designed with a load limit for the electrical power output on the section of track. It further comprises a communication system for the wireless transmission of driving instructions limiting the electrical power consumption to vehicles traveling on the section of track. The communication system has a track-side communication unit and vehicle-side communication units.The trackside communication unit can be designed as an RFID tag with a storage unit for driving instructions, with the vehicle-side communication unit being designed as an RFID reader that is configured to wirelessly read the stored driving instructions upon passage of the trackside communication unit. The trackside communication unit can also be used for the active transmission of driving instructions via dedicated short-range communication according to the IEEE 802.11p protocol.

[0008] (WLAN) or a mobile radio network according to the C-V2X or 5G standard. The power supply system also includes a control center that is set up to generate driving instructions for the section of track and transmit them via the communication system. The control center is set up to generate the driving instructions dynamically depending on the current power requirement on the section of track, the current operating data of the substation, the current or forecast traffic density on the section of track, the vehicle class of the vehicles using the section of track, the current weather data on the section of track and / or the current temperature of the overhead line.

[0009] The known systems are very complex in terms of the information and central and vehicle-based equipment required to generate a driver notification that reduces power consumption and transmit this from a central station to the vehicle device. The invention is therefore based on the object of providing a road vehicle of the type mentioned above with which traffic situations that pose a risk of overload can be avoided in a supply section.

[0010] The problem is solved by a generic road vehicle with the features specified in the characterising part of the patent claim.

[0011] The invention is therefore based on an electrically or hybrid-electrically powered road vehicle, in particular a heavy commercial vehicle, which comprises a pantograph for electrical power transmission by contacting contact wires of an electrical overhead line system that carry an electrical contact wire voltage. In traction mode, power is fed in from the overhead line system, and in recuperation mode, power is fed back into the overhead line system. According to the invention, the road vehicle further comprises a measuring device for detecting the currently applied contact wire voltage and a control device connected to the measuring device for switching the power transmission on and off.The control unit is designed to switch off the power feed when the contact wire voltage falls below a lower threshold and to switch it back on when the lower threshold is exceeded, after a randomly selected switch-on delay has elapsed. If the measuring device detects a drop in the contact wire voltage to a value below a lower threshold, the control unit switches off the power transmission to the road vehicle in order to prevent an overload situation in the supply section being traveled through. The contact wire voltage can then rise again, so that the power feed can be switched on again when the lower threshold is exceeded.In order to avoid an overload situation caused by the power transmission of all road vehicles traveling in a feed section being switched on almost simultaneously, a switch-on delay is randomly selected in each control unit and the power feed is only switched on again after the switch-on delay has expired. Because the switch-on delay is randomly selected, the switch-on times are also randomly distributed among the road vehicles in contact with the contact wires. This evens out the power consumption by these road vehicles, thus avoiding an overload in the feed section. Only vehicle-side equipment is required for this, and communication with a control center of the overhead line system is not necessary.

[0012] In an advantageous embodiment of the road vehicle according to the invention, the control unit is designed to randomly select a first time period from a predefinable first time window as the switch-on delay and to switch the power feed on again when the first time period has elapsed since the lower threshold value of the contact wire voltage was exceeded. A time window is specified for the switch-on delay, within which a first time period is randomly selected, for example by means of a random generator. The power feed of the road vehicles traveling in a feed section is switched on again after the first time period, which is specifically selected for each road vehicle, has elapsed. The random distribution of the first time periods softens the resumed power consumption, so that undesirable load peaks can be avoided.The time window can either be fixed or predefined depending on a typical traffic density or a typical load requirement for a supply section. The greater the load requirement in the supply section, the larger the time window is selected in order to stagger the activation of the power feed in the road vehicles.

[0013] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to randomly select a first voltage value from a predefinable first voltage range as a switch-on delay and to switch the power feed on again when the contact wire voltage, which increases again after the lower threshold value has been exceeded, has reached the first voltage value. A first voltage range is specified for the switch-on delay, within which a first voltage value is randomly selected, for example by means of a random generator. The power feed of the road vehicles traveling in a feed section is switched on again once the first voltage value, which is specifically selected for each road vehicle, has been reached. The random distribution of the first voltage values ​​softens the resumed power consumption, so that undesirable load peaks can be avoided.The first voltage range can either be fixed or predefined depending on a typical traffic density or a typical load requirement for a supply section. The greater the load requirement in the supply section, the larger the first voltage range is selected in order to disperse the switching on of the power feed in the road vehicles.

[0014] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to shut off the power supply when the contact wire voltage falls below the lower threshold after a randomly selected shutdown delay has elapsed. In this way, if an overload-related drop in the contact wire voltage below the lower threshold occurs, the load consumption in the supply section can be throttled not abruptly for all road vehicles simultaneously, but rather distributed over the shutdown delay, which, as described above, can be implemented using randomly generated times or voltage values.

[0015] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to switch off the power feedback when an upper threshold value of the contact wire voltage is exceeded and to switch it on again when the upper threshold value is undershot after a randomly selected switch-on delay has elapsed. If the measuring device detects an increase in the contact wire voltage to a value above the upper threshold value, the control unit switches off the power transmission from the road vehicle in order to prevent a further increase in the contact wire voltage in the supply section being traveled through. The contact wire voltage can therefore drop again, so that the power feedback can be switched on again when the upper threshold value is undershot.In order to avoid the power transmission of all road vehicles traveling in a feed section being switched on almost simultaneously, a switch-on delay is randomly selected in each control unit and the power feedback is only switched on again after the switch-on delay has expired. Due to the random selection of the switch-on delay, the switch-on times are also randomly distributed between the road vehicles in contact with the contact wires. This evens out the power output by these road vehicles, preventing a rapid rise in the contact wire voltage in the feed section. For this purpose, too, only vehicle-side equipment is required and communication with a control center of the overhead line system is not necessary.

[0016] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to randomly select a second time period from a predefinable second time window as a switch-on delay and to switch the power feedback back on again when the second time period has elapsed since the contact wire voltage fell below the upper threshold. A second time window is specified for the switch-on delay, within which a second time period is randomly selected, for example by means of a random generator. The power feedback of the road vehicles traveling in a supply section is switched on again after the second time period specifically selected for each road vehicle has elapsed. The random distribution of the second time periods softens the resumed power output, so that undesirable voltage peaks can be avoided.The second time window can either be fixed or predefined depending on a typical traffic density or a typical load output for a feed section. The greater the load output in the feed section, the larger the second time window is selected in order to disperse the activation of the power feedback in the road vehicles.

[0017] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to randomly select a second voltage value from a predefinable second voltage range as a switch-on delay and to switch the power feedback back on when the contact wire voltage, which drops again after falling below the upper threshold, has reached the second voltage value. A second voltage range is specified for the switch-on delay, within which a second voltage value is randomly selected, for example by means of a random generator. The power feedback of the road vehicles traveling in a supply section is switched on again once the second voltage value, which is specifically selected for each road vehicle, has been reached.The random distribution of the second voltage values ​​softens the resumed power output, thus avoiding undesirable voltage peaks in the contact wires. The second voltage range can either be fixed or specified as a function of a typical traffic density or a typical load output for a feed section. The greater the load output in the feed section, the larger the second voltage range selected in order to spread out the activation of the power feedback in the road vehicles.

[0018] In a further advantageous embodiment of the road vehicle according to the invention, the control unit is designed to deactivate the power feedback when the upper threshold of the contact wire voltage is exceeded, after a randomly selected deactivation delay has elapsed. In this way, when an overload-related increase in the contact wire voltage above the upper threshold occurs, the load output in the supply section can be increased not abruptly for all road vehicles simultaneously, but rather distributed over the deactivation delay, which, as described above, can be implemented using randomly generated times or voltage values.

[0019] Further features and advantages of the invention will become apparent from the following description of an embodiment with reference to the drawings, in which

[0020] FIG 1 shows an embodiment of a road vehicle according to the invention and

[0021] FIG 2 shows a voltage-power diagram for the road vehicle from FIG 1.

[0022] According to FIG 1, a road vehicle 10 according to the invention, for example a heavy commercial vehicle, with an electric or hybrid-electric traction drive 11, is supplied with electrical energy on a section S of a road network from an electrical overhead line system 20 installed on the trackside. For example, a right-hand lane L of a multi-lane motorway can be electrified by suspending two contact wires 21 designed as forward and return conductors along the lane L, parallel to one another and above the lane level. In a feed section of the overhead line system 20, a substation 22 provides a contact wire voltage U applied to the contact wires 21. For transmitting an electrical power P, the road vehicle 10 has a current collector 12, which can, for example, comprise a pantograph-like support frame and two contact rockers with contact strips supported thereon.During travel, the contact strips of the pantograph 12 are in electrical sliding contact with the respective contact wires 21 of the overhead line system 20. The overhead line system 11 is designed with load limits for the electrical power transmission on the track section S. The contact wire voltage U varies depending on the number of road vehicles 10 connected to the overhead line system 20 in the supply section, in particular depending on the number of road vehicles 10 traveling in traction mode and the number of road vehicles 10 traveling in recuperation mode, as well as the vehicle-specific power transmission of each individual road vehicle 10.

[0023] Therefore, according to FIG 2, electrical power P can only be transmitted between a road vehicle 10 and the overhead line system 20 within a value range [Ul; U2] of the contact wire voltage U predetermined by the design of the overhead line system 20. Power can only be fed in during traction operation of the road vehicle 10 below a lower threshold value Ul of the contact wire voltage U; likewise, power can not be fed back during recuperation operation of the road vehicle 10 above an upper threshold value U2 of the contact wire voltage U. Maximum power Pmax is transmitted within a value range [U3; U4] of the contact wire voltage U, which lies within the value range [Ul; U2] defined by the lower threshold value Ul and upper threshold value U2. During traction operation of the road vehicle 10, the power feed-in is throttled at a contact wire voltage U3 and switched off at the lower threshold value Ul.During recuperation mode of the road vehicle, the power feedback is throttled at a contact wire voltage U4 and switched off at the upper threshold value U2. For this purpose, the road vehicle 10 comprises a measuring device 13 for detecting the currently applied contact wire voltage U and a control device 14 connected to the measuring device for switching the power transmission on and off, which is designed to switch off the power feed when the contact wire voltage U falls below the lower threshold value Ul but also when the contact wire voltage U exceeds the upper threshold value U2.

[0024] According to the invention, the control unit 14 is designed to switch the power feed, which was switched off after the contact wire voltage U fell below the lower threshold value Ul, back on when the lower threshold value Ul is exceeded after a randomly selected switch-on delay has elapsed. The control unit 14 can be designed to randomly select a first time period from a predefinable first time window as the switch-on delay and to switch the power feed back on when the first time period has elapsed after the contact wire voltage U exceeded the lower threshold value Ul. However, the control unit 14 can also be designed to randomly select a first voltage value from a predefinable first voltage range as the switch-on delay and to switch the power feed back on when the contact wire voltage U, which increases again after the lower threshold value Ul has been exceeded, has reached the first voltage value.

[0025] This avoids an overload situation caused by the almost simultaneous switching on of the power transmission of all road vehicles 10 traveling in a supply section, by randomly selecting a switch-on delay in each vehicle-specific control unit 14, and only switching the power supply back on after the switch-on delay has elapsed. Due to the random selection of the switch-on delay, the switch-on times are also randomly distributed among the road vehicles 10 in contact with the contact wires 21. This evens out the power consumption by these road vehicles 10, thus avoiding an overload in the supply section.

[0026] The first time window or the first voltage range, within which the first time period or the first voltage value is randomly selected, for example using a random generator, can either be fixedly parameterized or specified depending on a typical traffic density or a typical load requirement for a supply section. The greater the load requirement in the supply section, the larger the first time window or the first voltage range is selected in order to be able to spread out the switching on of the power feed in the road vehicles 10.

[0027] The control unit 14 can also be configured to shut off the power supply when the contact wire voltage U falls below the lower threshold Ul, after a randomly selected shutdown delay has elapsed. In this way, if an overload-related drop in the contact wire voltage U below the lower threshold Ul occurs, the load consumption in the supply section can be throttled not abruptly for all road vehicles simultaneously, but rather distributed over the shutdown delay, which, as described above, can be implemented using randomly generated times or voltage values.

[0028] Furthermore, the control unit 14 can be designed to switch off the power feedback when the upper threshold value U2 of the contact wire voltage U is exceeded and to switch it back on when the upper threshold value U2 is undershot after a randomly selected switch-on delay has elapsed. If the measuring device 13 detects an increase in the contact wire voltage U to a value above the upper threshold value U2, the control unit 14 switches off the power transmission from the road vehicle 10 in order to prevent a further increase in the contact wire voltage U in the supply section being traveled through. The contact wire voltage U can therefore drop again, so that the power feedback can be switched on again when the upper threshold value U2 is undershot.In order to avoid an almost simultaneous switching on of the power transmission of all road vehicles 10 traveling in a supply section, a switch-on delay is randomly selected in each control unit 14, and the power feedback is only switched on again after the switch-on delay has elapsed. Due to the random selection of the switch-on delay, the switch-on times are also randomly distributed among the road vehicles 10 in contact with the contact wires 21. This evens out the power output by these road vehicles 10, whereby a rapid rise in the contact wire voltage U in the supply section can be avoided.

[0029] Analogous to traction operation, the control unit 14 for recuperation operation can be designed to randomly select a second time period from a predefinable second time window or a second voltage value from a second voltage range as a switch-on delay and to switch the power feedback back on when the second time period has elapsed or the contact wire voltage U has reached the second voltage value after the upper threshold value U2 of the contact wire voltage U has been undershot. The second time window or the second voltage range, within which the second time period or the second voltage value is randomly selected, for example by means of a random generator, can either have fixed parameters or be specified as a function of a typical traffic density or a typical load reference for a feed section.The greater the load output in the feed section, the larger the second time window or the second voltage range is selected in order to be able to spread out the switching on of the power feedback from the road vehicles 10.

[0030] The control unit 14 can also be configured to deactivate the power feedback when the upper threshold value U2 of the contact wire voltage U is exceeded, after a randomly selected deactivation delay has elapsed. In this way, when an overload-related increase in the contact wire voltage U above the upper threshold value U2 occurs, the load output in the supply section can be increased not abruptly for all road vehicles 10 simultaneously, but rather in a distributed manner over the deactivation delay, which, as described above, can be implemented using randomly generated times or voltage values.

Claims

Patent claims 1. Electrically or hybrid-electrically driven road vehicle (10), in particular a truck, comprising a current collector (12) for electrical power transmission by contacting an electrical contact wire voltage (U) carrying contact wires (21) of an electrical overhead line system (20), wherein in traction mode power is fed in from the overhead line system (20) and in recuperation mode power is fed back into the overhead line system (20), characterized by a measuring device (13) for detecting the currently applied contact wire voltage (U) and a control device (14) connected to the measuring device for switching the power transmission on and off, which control device is designed to switch the power feed off when the contact wire voltage (U) falls below a lower threshold value (Ul) and to switch it on again when the lower threshold value (Ul) is exceeded after a randomly selected switch-on delay has elapsed.

2. Road vehicle (10) according to claim 1, wherein the control unit (14) is designed to randomly select a first time period from a predeterminable first time window as a switch-on delay and to switch the power feed on again when the first time period has elapsed since the lower threshold value (Ul) of the contact wire voltage (U) has been exceeded.

3. Road vehicle (10) according to claim 1, wherein the control unit (14) is designed to randomly select a first voltage value from a predeterminable first voltage range as a switch-on delay and to switch the power feed on again when the contact wire voltage (U), which increases again after the lower threshold value (Ul) has been exceeded, has reached the first voltage value.

4. Road vehicle (10) according to one of claims 1 to 3, wherein the control unit (14) is designed to switch off the power supply when the contact wire voltage (U) falls below the lower threshold value (Ul) after a randomly selected switch-off delay has elapsed.

5. Road vehicle (10) according to one of claims 1 to 4, wherein the control unit (14) is designed to switch off the power feedback when an upper threshold value (U2) of the contact wire voltage (U) is exceeded and to switch it on again when the upper threshold value (U2) is undershot after a randomly selected switch-on delay has elapsed.

6. Road vehicle (10) according to claim 5, wherein the control unit (14) is designed to randomly select a second time period from a predeterminable second time window as a switch-on delay and to switch the power feedback back on again when the second time period has elapsed since the contact wire voltage (U) fell below the upper threshold value (U2).

7. Road vehicle (10) according to claim 5, wherein the control unit (14) is designed to randomly select a second voltage value from a predeterminable second voltage range as a switch-on delay and to switch the power feedback back on again when the contact wire voltage (U), which drops again after falling below the upper threshold value (U2), has reached the second voltage value.

8. Road vehicle (10) according to one of claims 5 to 7, wherein the control unit (14) is designed to switch off the power feedback when the upper threshold value (U2) of the contact wire voltage (U) is exceeded after a randomly selected switch-off delay has elapsed.

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