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EP-4026222-B1 - CHARGING SYSTEM FOR ELECTRIC VEHICLES

EP4026222B1EP 4026222 B1EP4026222 B1EP 4026222B1EP-4026222-B1

Inventors

  • SINGER, ARTHUR
  • NEUMANN, RALF

Dates

Publication Date
20260506
Application Date
20200903

Claims (15)

  1. A charging system (10) for electric vehicles (12), comprising: a number N of charge ports (LPj), each charge port (LPj) having an interface (14) for power exchange with an electric vehicle (12), a number of M modular energy storage direct converter systems (MESDCS) (Ui), a switchable connection matrix (16), and a control system (18), wherein each MESDCS (Ui) comprises a converter arm (76) having a first end (24) and a second end (26) and comprising a plurality of sequentially interconnected modules (78), wherein each module (78) comprises - at least one first terminal (80; 80a, 80b) and at least one second terminal (82; 82a, 82b), - a storage element (84) for electrical energy, in particular a battery, or an energy con version element, and - a plurality of module switches (86), wherein in each two adjacent modules (78) the at least one first terminal (80; 80a 80b) of one module (78) is connected either directly or via an intermediate component to the at least one second terminal (82; 82a, 82b) of the other module (78), wherein said plurality of module switches (86) allow at least for selectively deactivating the storage element (84) or energy conversion element of each module (78) and for connecting storage elements (84) or energy conversion elements of adjacent modules (78) in series, wherein said control system (18) is configured to control an output voltage of each MESDCS (Ui), based on information regarding the current charge state of the storage elements (84) or voltage or output power of-energy conversion elements, and by means of actuating at least a part of said plurality of module switches (86) depending on this information such that the converter arm (76) as a whole supplies said output voltage, and wherein said switchable connection matrix (16) is configured to connect, under the control of said control system (18), one or more selected MESDCS (Ui) with each given charge port (LPj), and is further configured to connect one or more selected MESDCS (Ui) with a power source (30), characterised in that the control system (18) is configured to ensure that no MESDCS (Ui) is simultaneously connected to the power source (30) and to a charge port (LPj).
  2. The charging system (10) of claim 1, wherein the connection matrix is configured to connect, under control of said control system (18), one or more selected MESDCS (Ui) directly or indirectly with a ground associated with the power source (30), when said one or more selected MESDCS (Ui) is connected with a phase of said power source (30), and to disconnect said one or more selected MESDCS (Ui) from the ground of the power source (30) when said one or more selected MESDCS (Ui) is/are connected with a charge port (LPj).
  3. The charging system (10) of claim 1 or 2, wherein for charging an electric vehicle (12) at a given charge port with a desired charging voltage, the control system (18) is configured to establish at least two, and preferably all of the following charging states: - a single charging state, in which the control system (18) controls the output voltage of a selected MESDCS (Ui) to match said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect only the select ed MESDCS (Ui) to said given charge port (LPj), - a parallel charging state, in which the control system (18) controls the output voltages of at least two selected MESDCS (Ui) to each match said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect each of the at least two selected MESDCS (Ui) to said given charge port, and - a serial charging state, in which the control system (18) controls the output voltages of a group of two or more selected MESDCS (Ui) such that their sum matches said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect said group of two or more selected MESDCS (Ui) in series and to connect said serially connected group to said given charge port (LPj).
  4. The charging system (10) of one of the preceding claims, wherein said control system (18) is configured to establish a reverse charging state, in which the control system (18) controls the output voltage of one or more selected MESDCS (Ui) to a value lower than the current voltage of a battery of an electric vehicle (12) connected to a given charge port (LPj), and controls the switchable connection matrix (16) to connect said one or more selected MESDCS (Ui) to said given charge port (LPj), such that energy storages (84) within said one or more selected MESDCS (Ui) are charged with power received from the battery of said electric vehicle (12) connected to said given charge port (LPj).
  5. The charging system (10) of one of the preceding claims, wherein said control system (18) is configured to establish a power source support state, in which the control system (18) controls the output voltage of one or more selected MESDCS (Ui) to a value higher than a voltage of the power source (30) and controls the connection matrix (16) to connect said one or more selected MESDCS (Ui) to said power source (30).
  6. The charging system (10) of claim 5, wherein connecting said one or more selected MESDCS (Ui) to said power source in said power source (30) support state comprises connecting said one or more selected MESDCS (Ui) to a given phase (30A, 30B, 30C) of said power source (30), wherein the control system (18) further controls the output voltage of said one or more selected MESDCS (Ui) to follow a time varying phase volt age of said power source phase (30A, 30B, 30C), such that it is at each instance in time higher than the time varying phase voltage.
  7. The charging system (10) of one of the preceding claims, wherein said switchable connection matrix (16) has a first part (16A), said first part (16A) comprising N first terminals (30) each connected with a corresponding one of said N charge ports (LPj), and M second terminals (22), each connected with a first end of a corresponding MESDCS (Ui), and wherein said switchable connection matrix (16) is switchable, under control of said control system (18), to selectively connect each of said first terminals (20) with selected one or more second terminals (22).
  8. The charging system (10) of claim 7, wherein said first part (16A) of said switchable connection matrix (16) further comprises a number of L third terminals (28) each connected to a corresponding phase (30A, 30B, 30C) of said power source (30) or to ground, wherein said switchable connection matrix (16) is switchable, under control of said control system (18), to selectively connect each of said third terminals (28) with selected one or more second terminals (22), and wherein said switchable connection matrix (16) may further be switchable, under control of said control system (18), to connect two second terminals (22) with each other, but not with any of said first terminals (20).
  9. A method of operating a charging system (10) for electric vehicles (12), said charging system comprising: a number N of charge ports (LPj), each charge port (LPj) having an interface (14) for power exchange with an electric vehicle (12), a number of M modular energy storage direct converter systems (MESDCS) (Ui), a switchable connection matrix (16), and a control system (18), wherein each MESDCS (Ui) comprises a converter arm (76) having a first end (24) and a second end (26) and comprising a plurality of sequentially interconnected modules (78), wherein each module (78) comprises - at least one first terminal (80; 80a, 80b) and at least one second terminal (82; 82a, 82b), - a storage element (84) for electrical energy, in particular a battery, or an energy con version element, and - a plurality of module switches (86), wherein in each two adjacent modules (78) the at least one first terminal (80; 80a 80b) of one module (78) is connected either directly or via an intermediate component to the at least one second terminal (82; 82a, 82b) of the other module (78), wherein said plurality of module switches (86) allow at least for selectively deactivating the storage element (84) or energy conversion element of each module (78) and for connecting storage elements (84) or energy conversion elements of adjacent modules (78) in series, wherein said method comprises controlling an output voltage of each MESDCS (Ui), based on information regarding the current charge state of the storage elements (84) or voltage or output power of-energy conversion elements, by actuating at least a part of said plurality of module switches (86) depending on this information such that the converter arm (76) as a whole supplies said output voltage, and wherein said operation comprises connecting one or more selected MESDCS (Ui) with each given charge port (LPj), and comprises connecting one or more selected MESDCS (Ui) with a power source (30), characterised in that the method is carried out such that it is constantly avoided that any MESDCS (Ui) is simultaneously connected to the power source (30) and to a charge port (LPj),
  10. The method of claim 9, wherein the method further comprises selectively connecting, by means of said connection matrix (16), one or more MESDCS (Ui) directly or indirectly with a ground associated with the power source (30), when said one or more selected MESDCS (Ui) is connected with a phase of said power source (30), and disconnecting said one or more MESDCS (Ui) from the ground of the power source (30) when said one or more selected MESDCS (Ui) are connected with a charge port (LPj).
  11. The method of claim 9 or 10, wherein for charging an electric vehicle (12) at a given charge port with a desired charging voltage, the method comprises establishing at least two, and preferably all of the following charging states: - a single charging state, in which the control system (18) controls the output voltage of a selected MESDCS (Ui) to match said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect only the select ed MESDCS (Ui) to said given charge port (LPj), - a parallel charging state, in which the control system (18) controls the output voltages of at least two selected MESDCS (Ui) to each match said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect each of the at least two selected MESDCS (Ui) to said given charge port, and - a serial charging state, in which the control system (18) controls the output voltages of a group of two or more selected MESDCS (Ui) such that their sum matches said desired charging voltage at said given charge port (LPj), and controls the connection matrix (16) to connect said group of two or more selected MESDCS (Ui) in series and to connect said serially connected group to said given charge port (LPj).
  12. The method of one of claims 9 to 11, wherein said method further comprises establishing a reverse charging state, in which the output voltage of one or more selected MESDCS (Ui) controlled to assume a value lower than the current voltage of a battery of an electric vehicle (12) connected to a given charge port (LPj), and the switchable connection matrix (16) is controlled to connect said one or more selected MESDCS (Ui) to said given charge port (LPj), such that energy storages (84) within said one or more selected MESDCS (Ui) are charged with power received from the battery of said electric vehicle (12) connected to said given charge port (LPj).
  13. The method of one of claims 9 to 12, wherein said method further comprises establishing a power source support state, in which the output voltage of one or more select ed MESDCS (Ui) is controlled to assume a value higher than a voltage of the power source (30) and the connection matrix (16) is controlled to connect said one or more selected MESDCS (Ui) to said power source (30).
  14. The method of claim 13, wherein connecting said one or more selected MESDCS (Ui) to said power source in said power source (30) support state comprises connecting said one or more selected MESDCS (Ui) to a given phase (30A, 30B, 30C) of said power source (30), wherein the method further comprises controlling the output voltage of said one or more selected MESDCS (Ui) to follow a time varying phase voltage of said power source phase (30A, 30B, 30C), such that it is at each instance in time higher than the time varying phase voltage.
  15. The method of one of claims 9 to 14, wherein said switchable connection matrix (16) has a first part (16A), said first part (16A) comprising N first terminals (30) each connected with a corresponding one of said N charge ports (LPj), and M second terminals (22), each connected with a first end of a corresponding MESDCS (Ui), and wherein said switchable connection matrix (16) is switchable, under control of said control system (18), to selectively connect each of said first terminals (20) with selected one or more second terminals (22).

Description

FIELD OF THE INVENTION The present invention is in the field of electric mobility. More particularly, the present invention relates to a charging system for electric vehicles. BACKGROUND OF THE INVENTION The number of electric vehicles worldwide is increasing rapidly. Together with the increase in number of electric vehicles, there is a growing demand for charging systems. In prior art charging systems, typically an AC/DC converter is used, for converting an AC voltage provided by a power network to a DC voltage. Since different electric vehicles require different charging voltages, it is generally not possible to simply use this DC voltage directly for simultaneous charging different vehicles at different charge ports. Instead, in a conventional charging system, the DC voltage is supplied to a DC bus, and an additional DC/DC converter is provided between the DC bus and each individual charge port, where the DC/DC converter allows for providing the desired charging voltage. These prior art charging systems lack flexibility to meet possibly changing charging demands. Namely, the DC/DC converters are designed for a maximum charging power and for a maximum charging voltage. If new types of electric vehicles become availabe that require higher charging voltages, or higher charging powers, the DC/DC converters have to be replaced. On the other hand, if the DC/DC converters are over-designed to be able to serve all types of vehicles, inefficient use is made of the hardware most of the time. A further difficulty with the increasing demand for charging systems is the local supply with power from the power network. The costs for providing additional charging systems increase significantly, if additional medium voltage networks have to be provided for their power supply, such as networks providing a voltage of more than e.g. 1 kV and typically in a range of 10 kV to 50 kV. On the other hand, low-voltage power networks with voltages of less than 1 kV, although available at many places, usually do not provide enough power to charge a plurality of electric vehicles with high charging power at the same time. US 2013/006 9592 A1 discloses a charging system with a plurality of charge ports, a plurality of power converters for converting power from a power source to a desired format for charging a vehicle, and a switchable connection matrix for connecting at least one power converter with at least one charging port. EP 2 815 913 A1 discloses a recharging system for electric vehicles. VASILADIOTIS MICHAIL ET AL: "A Modular Multiport Power Electronic Transformer With Integrated Split Battery Energy Storage for Versatile Ultrafast EV Charging Stations", IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, IEEE D2 SERVICE CENTER, PISCATAWAY, NJ, USA, vol. 62, no. 5, 1 May 2015 (2015-05-01), pages 3213-3222, XP011577635, ISSN: 0278-0046, DOI: 10.1109/TIE.2014.2367237 discloses a Modular Multiport Power Electronic Transformer. DE 10 2014 110410 A1 discloses a modular energy storage direct inverter system. SUMMARY OF THE INVENTION The problem underlying the invention is to provide a charging system for electric vehicles, that allows for serving different types of vehicles with different charging demands, while making optimum use of the available hardware as well as of the available power supplied from a power source, such as a power network. The electric vehicles may in some embodiments be electric cars, and in the specific examples described herein, reference is mainly made to cars for illustration purposes. However, the invention is not limited to this, but instead generally relates to any type of electric vehicle, including electric cars, motorcycles, scooters, trucks, tractors, boats, or aircrafts. This problem is solved by a charging system according to claim 1. Favorable embodiments are defined in the dependent claims. This problem is further solved by a method of operating a charging system according to claim 30. Favorable embodiments of the method are defined in the corresponding dependent claims. According to one aspect, the present invention provides a charging system for electric vehicles, comprising a number N of charge ports, each charge port having an interface for power exchange with an electric vehicle, a number of M modular energy storage direct converter systems (MESDCS), a switchable connection matrix, and a control system. Each MESDCS comprises a converter arm having a first end and a second end and comprising a plurality of sequentially interconnected modules, wherein each module comprises at least one first terminal and at least one second terminal,a storage element for electrical energy, in particular a battery, or an energy conversion element, anda plurality of module switches. In each two adjacent modules, the at least one first terminal of one module is connected either directly or via an intermediate component to the at least one second terminal of the other module. The said plurality of module switches allow at