SYSTEM FOR ELECTRICALLY FEEDING ELECTRICALLY POWERED VEHICLES

Abstract

System (1) for electrically feeding electrically powered vehicles (2a-b), comprising electric conductor(s) (3) extending along a road section (4) and a central electronic control unit, CECU (8). The vehicles comprise a current collector (5a-b), an onboard energy storage device (7a-b) and a thereto connected vehicle electronic control unit, VECU (6a-b). The VECU is configured to determine a current required power and a current energy storage status, and to send a signal to the CECU indicating the current required power and the energy storage status. The CECU is configured to determine a maximum power available via said electric conductor and a power to be received for each vehicle such that the maximum power is not exceeded and send at least one power control signal to each VECU indicating the power to be received. The VECU is configured to control received power in response to said at least one power control signal.

Claims

1.-17. (canceled)

18. System for electrically feeding electrically powered vehicles, comprising: at least one electric conductor adapted to be electrically energized and extending along a road section on which the at least one vehicle is adapted to travel; at least two electrically powered vehicles, each comprising at least one current collector adapted to connect the vehicle electrically to said at least one electric conductor, and a vehicle electronic control unit (VECU) being electrically connected to said current collector, said VECU being directly or indirectly connected to an onboard energy storage device of said vehicle; and a central electronic control unit (CECU), wherein said VECU and CECU are configured for communication with each other, wherein each VECU is configured to determine a current required power for propulsion of the vehicle and a current energy storage status of said energy storage device, and to send at least one signal to the CECU indicating said current required power and said energy storage status, wherein said CECU is configured to determine a maximum power available, and to, based on said at least one signal from each VECU, determine a power to be received for each vehicle such that a maximum power is not exceeded, and send at least one power control signal to each VECU indicating said power to be received, and wherein said VECU is configured to control received power via the current collector in response to said at least one power control signal.

19. System according to claim 18, wherein at least one of said at least one electric conductor is formed by consecutively arranged conductor segments, wherein said CECU is configured to determine which conductor segment or segments the vehicles are connected to, and to determine a maximum power available from said conductor segment or segments, and to determine said power to be received for each vehicle such that the maximum power for each conductor segment is not exceeded.

20. System according to claim 19, wherein said power to be received is determined such that each vehicle is able to propel along the full length of the conductor segment to which said vehicle is connected.

21. System according to claim 18, wherein each VECU is configured to determine said current required power for propulsion of the vehicle at a target speed, and wherein the CECU is configured to determine said power to be received for each vehicle such that the maximum power is not exceeded while each vehicle maintains its target speed.

22. System according to claim 21, wherein said CECU is configured to determine a desired target speed for each vehicle, and to send at least one speed control signal to each VECU indicating said desired target speed, and wherein said VECU is configured to adjust its target speed in response to said at least one speed control signal.

23. System according to claim 22, wherein said CECU is configured to, if the sum of the powers to be received for each vehicle connected to a conductor segment exceeds the maximum power for said conductor segment, reduce the speed of one or more vehicles by lowering said desired target speed for at least one vehicle connected to said conductor segment.

24. System according to claim 22, wherein said CECU is configured to determine a desired end position for each vehicle, and to determine a current location for each vehicle, wherein said CECU is configured to execute a learning or predictive control algorithm configured to determine the power to be received for each vehicle and the desired target speed for each vehicle to minimize the time for each vehicle to reach its desired end position while not exceeding the maximum power available for each conductor segment.

25. System according to claim 24, wherein said algorithm is further configured to determine said power to be received and said target speed for each vehicle such that the energy storage status for each vehicle is substantially full at respective end positions.

26. System according to claim 24, wherein said VECU is configured to send a load carrying signal to the CECU indicating a priority of the load content in the vehicle, and wherein said algorithm is further configured to determine said power to be received and said target speed for each vehicle further based on said load carrying signals such that vehicles carrying load content having high priority reaches the respective end positions faster than vehicles carrying load content having lower priority.

27. System according to claim 22, wherein said vehicle comprises autonomous driving means being configured to co-act with said VECU to accelerate and/or decelerate the vehicle in response to said at least one speed control signal received by said VECU.

28. System according to claim 18, wherein said VECU and CECU are configured for two-way communication with each other via said at least one electric conductor.

29. System according to claim 18, wherein each VECU and said CECU each comprise wireless communication means configured for wireless two-way communication between said VECU and CECU.

30. System according to claim 18, wherein at least one of said at least one electric conductor is formed by consecutively arranged conductor segments, and wherein said CECU is configured to determine a location of the at least one electrically powered vehicle by means of determining which conductor segment the vehicle is connected to.

31. System according to claim 30, wherein said conductor segments are connected to a source of electric power via respective switches, wherein said CECU is arranged in communication with said switches, and wherein said location is determined using at least one status signals from the switches.

32. System according to claim 18, wherein said VECU comprises a configurable interface adapted to connect to one or more already existing electronic control units of the vehicle.

33. System according to claim 18, wherein at least one of said vehicles comprises at least one position sensor connected to the VECU and being arranged to sense the relative position between the at least one electric conductor and the vehicle, wherein said vehicle comprises autonomous steering means configured to co-act with the VECU to autonomously steer the vehicle in response to a signal from said at least one position sensor such that the vehicle follows the at least one electric conductor.

34. Method for controlling a system for electrically feeding electrically powered vehicles, said system comprising: at least one electric conductor adapted to be electrically energized and extending along a road section on which the at least one vehicle is adapted to travel; and at least two electrically powered vehicles, each comprising an onboard energy storage device and at least one current collector adapted to connect the vehicle electrically to said at least one electric conductor, said method comprising: determining a current required power for propulsion of the vehicle; determining a current energy storage status of said energy storage device; determining a maximum power available; determining, based on said current required power and current energy storage status for each vehicle, a power to be received for each vehicle such that a maximum power is not exceeded; and controlling, for each vehicle, a received power via the current collector corresponding to the determined power.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Above discussed and other aspects of the present invention will now be described in more detail using the appended drawings, which show presently preferred embodiments of the invention, wherein:

[0036] FIG. 1 shows a schematic side view illustration of an embodiment of the system according to the first aspect of the invention;

[0037] FIG. 2 shows a top view illustration of parts of the system in FIG. 1;

[0038] FIG. 3 shows a schematic side view illustration of another embodiment of the system according to the first aspect of the invention, and

[0039] FIG. 4 shows a flowchart of an embodiment of the method according to the second aspect of the invention.

DETAILED DESCRIPTION

[0040] FIG. 1 shows a schematic side view illustration of an embodiment of the system according to the first aspect of the invention. The system 1 comprises an electric conductor 3 suspended above and extending along a road section 4 on which electrically powered vehicles 2a, 2b travel. A central electronic control unit, CECU, 8 is electrically connected to the electric conductor 3. The vehicle 2a comprises a current collector 5a connecting the vehicle electrically to the electric conductor 3, and a vehicle electronic control unit, VECU, 6a being electrically connected to the current collector 5a, where the VECU is connected to a battery set 7a of the vehicle. The current collector 5a is connected to the vehicle roof by means of at least one elongated arm configured to displace the current collector laterally and vertically to connect with the electric conductor 3. The electrically powered vehicle 2a is configured to be electrically propellable by means of electric power from its battery set 7a and/or from the current collector 5a. The VECU and CECU are configured for two-way wireless electric communication with each other using wireless communication modules, here illustrated (greatly exaggerated in size) as antenna elements 6a, 8. The second vehicle 2b comprises a corresponding current collector 5b, VECU 6b with wireless communication module 6b and battery set 7b as the first vehicle 2a.

[0041] Each VECU is configured to determine a current required power for propulsion of the vehicle, which current required power may correspond to the required power for propulsion at the present speed of the vehicle or at a target speed, and a current battery charge status of said battery set, and to send at least one signal to the CECU indicating said current required power and said battery charge status. The CECU 8 is configured to determine a maximum power available via said electric conductor 3, and to, based on said at least one signal from each VECU, 6a, 6b determine a power to be received for each vehicle 2a, 2b such that the maximum power is not exceeded, and send at least one power control signal to each VECU 6a, 6b indicating said power to be received. Each VECU 6a, 6b is furthermore configured to control received power via the current collector 5a, 5b in response to the at least one power control signal.

[0042] In an example, the vehicles 2a, 2b propel at the same speed V. Since the vehicles are identical and carry the same load, the current required power P.sub.req is also the same for both vehicles. This current required power is determined by the respective VECU (having knowledge of currently used power by means of signals received from the vehicle). The first vehicle has a battery charge status of 0%, while the second vehicle has 100%. The VECU's each send a signal to the CECU indicating these figures. The CECU determines that the maximum power available P max from the conductor is less than 2*P.sub.req. Based on the charge status for the first vehicle, the CECU determines that its power to be received P.sub.rec1 must be at least P.sub.req. Based on the charge status for the second vehicle, the CECU determines that its power to be received P.sub.rec2 can be less than P req. The CECU may for example be configured to use an algorithm attempting to achieve balanced battery charge status of all vehicles, and therefore determines that P.sub.rec1=P.sub.max and P.sub.rec2=0. The CECU sends a power control signal to each VECU 6a, 6b indicating the respective power to be received. Each VECU 6a, 6b controls received power via the current collector 5a, 5b in response to the power control signal. The algorithm repeats this determination continuously, and eventually, when the battery charge statuses of the vehicles are equal, the second vehicle will start receiving power via its current collector.

[0043] The CECU 8 is furthermore configured to optionally determine a desired target speed for each vehicle 2a, 2b, and to send at least one speed control signal to each VECU 5a, 5b indicating said desired target speed. This functionality may be used to reduce the speed of one or more vehicles by lowering said desired target speed for at least one vehicle connected to said conductor segment. Assuming for instance that two vehicles are connected to the electric conductor, and that the battery charge status of both vehicles is 0%, then the sum of the current required powers P.sub.rec1+P.sub.rec2 for the vehicles to propel at their respective present target speeds may exceed P.sub.max, which makes propulsion at the present target speeds impossible. In such a case, the CECU may determine lower desired target speeds for the vehicles and send speed control signals to the VECU's such that propulsion is possible without exceeding the capacity of the electric conductor.

[0044] FIG. 2 shows a top view illustration of parts of the system in FIG. 1. The vehicle 2a comprises a current collector 5a being provided with a position sensor 14a-c connected to the VECU 6a and being arranged to sense the relative position between the electric conductor 3 and the vehicle 2a. The position sensor comprises a coil 14a for generating a magnetic field and laterally spaced apart coils 14b, 14c for sensing a variation of the generated magnetic field to generate a signal correlated to a horizontal distance between coil 14a and the at least one electric conductor. Such a configuration with three coils is disclosed in applicants' patent EP2552735B1 and will not be described in further detail here. The vehicle 2a comprises autonomous steering means in the form of an (already present) electronic control unit 13 of the vehicle and a thereto electronically controlled steering device/actuator 15, which are electrically connected to and configured to co-act with the VECU 6a to autonomously steer the vehicle in response to a signal from the position sensor 14a-c such that the vehicle follows the at least one electric conductor. In other words, the VECU steers the vehicle to follow the electric conductor/conductor segments. The vehicle 2a further comprises autonomous driving means in the form of an algorithm in the already present electric control unit 13 of the vehicle, which controls the vehicle speed by controlling the power output to electric motors of the vehicle to accelerate and/or decelerate the vehicle in response to the at least one speed control signal received by said VECU.

[0045] FIG. 2 further illustrates that the VECU 6a is indirectly connected to the battery set 7a via a battery management system, BMS, 7a which is arranged to monitor the charge status and health status of each battery cell of the battery set.

[0046] FIG. 2 further illustrates that the VECU 6a comprises a user-configurable interface 6a which in this embodiment is configured to connect to the electronic control unit 13, the current collector 5a and to the BMS 7a.

[0047] Vehicle 2b shown in FIG. 1 comprises the same features as vehicle 2a described above with reference to FIG. 2.

[0048] FIG. 3 shows a schematic side view illustration of another embodiment of the system according to the first aspect of the invention. The system 101 corresponds to that shown in FIGS. 1-2 and described above in the sense that it comprises an electric conductor 103 suspended above and extending along a road section 104 on which electrically powered vehicles 102a, 102b, 102c travel, and in that a central electronic control unit, CECU, 108 is electrically connected to the electric conductor 103. The vehicles 102a-c correspond to vehicles 2a-b in FIG. 1 in that they each comprise a current collector 105a-c, a vehicle electronic control unit, VECU, 106a-c and a battery set 107a-c.

[0049] The system in FIG. 3 however differs from the system in FIG. 1-2 in several ways. Firstly, the electric conductor 103 is formed from three consecutively arranged electric conductor segments 103a-c. Each conductor segment is connected to a source of electric power 111, here illustrated in the form of a main electric conductor line, via respective switches 112a-c. Secondly, the VECU and CECU are configured for two-way electric communication with each other via the electric conductor, i.e. via conductor segments 103a-c and switches 112a-c. Another embodiment corresponds to the embodiment in FIG. 3 except that the VECU and CECU communicate wirelessly as in FIG. 1.

[0050] The CECU 108 is configured to determine which conductor segment or segments 103a-c the vehicles 102a-c are connected to, and to determine a maximum power available P.sub.max1, P.sub.max2, P.sub.max3 for the respective conductor segments, and to determine the power to be received P.sub.rec1, P.sub.rec2, P.sub.rec3 for each vehicle such that the maximum power for each conductor segment is not exceeded while each vehicle maintains its target speed. The maximum power available P.sub.max1, P.sub.max2, P.sub.max3 for the respective conductor segments is determined based on global constraints such that the overall power available via main electric conductor line 111, and further based on local constraints such that the power draw of adjacent conductor segments.

[0051] The CECU 108 is configured to determine a location of the vehicles 102a-c by means of determining which conductor segment 103a-c the vehicle is connected to. This is determined using status signals obtained from the switches 112a-c and/or a status signal from the vehicles indicating which switch the vehicle is connected to.

[0052] The CECU 108 is furthermore configured to determine the power to be received P.sub.rec1, P.sub.rec2, P.sub.rec3 for each vehicle such that each vehicle is able to propel at said target speed along the full length of the conductor segment to which said vehicle is connected. The power to be received for each vehicle is determined by first determining, based on the current charge status and the required power for propulsion at the target speed, the minimum required power P.sub.req1min, P.sub.req2min, P.sub.req3min to be received for each vehicle to be able to propel the full remaining length of the conductor segment. This calculation is further based on known information regarding the lengths of the conductor segments and the determined locations of the vehicles. The CECU 8 is furthermore configured to determine a desired target speed for each vehicle 102a-c in a corresponding manner as described above with reference to FIG. 1. In the above-mentioned determination, the power to be received and minimum required power for each vehicle are assumed to be constant over the length of the respective conductor segment.

[0053] In an example where the sum of the required powers P.sub.req1, P.sub.req2 for propulsion of the vehicles 102a, 102b connected to the conductor segment 103a exceeds the maximum power available P.sub.max1 via said conductor segment, the CECU 108 may adjust the powers to be received P.sub.rec1, P.sub.rec2 for the vehicles to a lower value that the corresponding required powers P.sub.req1, P.sub.req2 for propulsion at the target speed provided, provided that the lower value is above the determined minimum required power P.sub.req1min, P.sub.req2min. Once the vehicle reaches a subsequent conductor segment, a new determination of minimum required power is conducted. In an example where one or more of the determined required powers P.sub.req1, P.sub.req2 is/are below P.sub.req1min, P.sub.req2min, the CECU determines a new desired target speed for the vehicle(s), being lower than the present target speed of one or more of the vehicles, and sends at least one speed control signal to the VECU(s) indicating said desired target speed. Based on an iterative process, the target speed(s) is/are reduced until it is determined that each vehicle is able to propel at its target speed along the full length of the conductor segment.

[0054] The CECU 108 is furthermore configured to optionally determine a desired end position for each vehicle 102a-c, wherein the CECU is configured to execute a discrete model predictive control (MPC) algorithm, where a target speed for each vehicle and each conductor segment constitutes one set of optimization variables, and a power to be received for each vehicle and each conductor segment constitutes a further set of optimization variables, and where the cost function is a sum of the squared time for each vehicle to reach its desired end position. The power to be received and the target speed for each vehicle is constant over a given conductor segment. The algorithm is further configured to determine said power to be received and said target speed for each vehicle such that the charge status for each vehicle is substantially full at respective end positions. This is achieved by means of the cost function further comprising a function penalizing deviation from full battery charge status for each vehicle. The desired end position may for example be to the left in the figure, where vehicle 102a is already positioned. The time for a vehicle to reach its desired end position is determined as the sum of the times needed to propel along the conductor segments (or portions thereof) remaining up to the desired end position. The time needed to propel along a conductor segment (or portion thereof remaining) is modelled in a simplified manner as the length of the conductor segment (or portion thereof remaining) divided by the target speed of the vehicle for this conductor segment (assuming a constant target speed).

[0055] FIG. 4 shows a flowchart of an embodiment of the method according to the second aspect of the invention. The method comprises determining 201 a current required power for propulsion of the vehicle at a target speed, determining 202 a current battery charge status of said battery set, determining 203 a maximum power available via said electric conductor, determining 204, based on said current required power and current battery charge status for each vehicle, a power to be received for each vehicle such that the maximum power is not exceeded while each vehicle maintains its target speed, and controlling 205, for each vehicle, a received power via the current collector corresponding to the determined power. The method steps may be performed by a CECU and VECU's in a corresponding manner described above with reference to FIGS. 1-3.

[0056] The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention. For example, in FIGS. 1/3, the electric conductor is shown suspended above the road surface. Other embodiments are identical to those of FIGS. 1/3, except for that the electric conductor is recessed in the road surface and the current collector is arranged for connection with the recessed electric conductor, for example as shown in WO 2010/140964. In FIGS. 1/3, the CECU 8/108 is shown as stationary, i.e., is located at a fixed location and being electrically connected to the (also) stationary electric conductor. In other embodiments, the CECU may be non-stationary, for instance being located on one of the vehicles. The electric conductor in FIG. 3 is shown as being formed by three conductor segments, but may in other embodiments comprises additional (or fewer) conductor segments. In the embodiments above, the energy storage devices are in the form of battery sets. These battery sets may be replaced with other types of energy storage devices such as hydraulic accumulators, flywheels or supercapacitors.