GB2602710A - Method and system for configuring an AC battery for AC charging - Google Patents

Method and system for configuring an AC battery for AC charging Download PDF

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Publication number
GB2602710A
GB2602710A GB2115870.4A GB202115870A GB2602710A GB 2602710 A GB2602710 A GB 2602710A GB 202115870 A GB202115870 A GB 202115870A GB 2602710 A GB2602710 A GB 2602710A
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United Kingdom
Prior art keywords
battery
charging
voltage level
phase
strings
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Application number
GB2115870.4A
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GB2602710B (en
Inventor
Specht Eduard
Helmut Dibos Hermann
Kacetl Jan
Simon Daniel
Kacetl Tomas
Jaensch Malte
Götz Stefan
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Dr Ing HCF Porsche AG
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Dr Ing HCF Porsche AG
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/14—Conductive energy transfer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/21—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having the same nominal voltage
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0024—Parallel/serial switching of connection of batteries to charge or load circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2210/00—Converter types
    • B60L2210/30—AC to DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/40—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries adapted for charging from various sources, e.g. AC, DC or multivoltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/40—The network being an on-board power network, i.e. within a vehicle
    • H02J2310/48—The network being an on-board power network, i.e. within a vehicle for electric vehicles [EV] or hybrid vehicles [HEV]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
    • Y02T10/92—Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

An AC battery 110 comprises a central controller and three strings 111, 112, 113 each having at least two battery modules. Each battery module has at least one energy store and at least two power semiconductor switches, which connect the respective battery module in series or in parallel or in bypass to another battery module. The three strings 111, 112, 113 provide a respective phase with a phase voltage level 102. The AC battery 110 is charged by a charging source 220 via a charging circuit, which provides alternating current at a charging voltage level 221 and has at least one switch 206 and a filter 230. The state of charge of the energy stores is monitored by the central controller during charging, and the instantaneous value of the phase voltage level 102 is adjusted to a time profile of the instantaneous value of the charging voltage level 221 according to a continued evaluation of the states of charge of the energy stores and by a dynamic driving of the power semiconductor switches. The AC battery 110 is configured by interconnection of the strings 111, 112, 113 with one another and with respect to a reference potential 101 according to a comparison between the phase voltage level 102 and the charging voltage level 221 in such a way that an output voltage level of the AC battery is greater than or equal to the charging voltage level 221. The battery can be adjusted to a particular charging voltage level 221 even as it ages and its voltage decreases.

Description

Method and system for configuring an AC battery for AC charging The present invention relates to a method for AC charging of a reconfigurable three-phase AC battery. A system on which the method is executed is also presented.
Batteries or battery packs conventionally installed in electric vehicles today are fixedly wired units, for example individual energy cells fixedly wired to one another, whose series-parallel configuration prescribed by the wiring cannot be changed. This means that the same voltage used for discharging, for example in a pulse inverter, is also used for charging. The fixed wiring determines a maximum voltage of the battery in the case of a full state of charge and without aging phenomena. If the state of charge drops, the voltage of the fixedly wired battery can decrease by up to 50%.
Inverters are used to convert a DC voltage of a traction battery to an AC voltage required for an electric motor. Modern inverters, for example formed by modular multi-level converters in which a plurality of electrically connected modules, which each have at least one energy store and at least two semiconductor switches for interconnecting the energy stores between the modules, are arranged in at least one module string in this case constitute a development of the aforementioned fixedly interconnected batteries. A dynamic interconnection can thus produce an AC voltage, for example for operating an electric machine, from a DC voltage of the energy stores. An example is the modular multi-level converter, also abbreviated to MMC or M2C, disclosed by R. Marquardt in document US 2018/0109202. A central controller usually controls the respective interconnection of the modules.
Austrian document AT 508 279 Al describes a method and an arrangement for charging batteries connected in series. The batteries are charged individually or in parallel in subgroups using separate charging means.
Document DE 10 2010 052 934 Al discloses a new multi-level converter topology with the possibility for dynamic series and parallel connection of individual modules. Each individual module has at least four internal switching elements, an energy storage element and four terminals and can interconnect the energy storage element in series or in parallel with the energy storage elements of adjacent a connected individual modules by way of a respective switching position of internal switching elements.
Document DE 10 2014 204 260 Al describes a method and a system for controlling an electric vehicle during charging. The control is designed to charge the traction battery to a target state of charge, to condition the traction battery to a target battery temperature and to condition the vehicle cabin to a target cabin temperature.
However, a battery is also not provided with further control components for DC charging as standard. A charging socket is connected directly to connection points of the battery or of the battery pack without any DC isolation, wherein a charging power is determined by a charging control. A conventional battery pack can thus be charged only by a controlled DC charge source with a prescribed voltage level, wherein 400 V and 800 V are typical voltage levels. If a rated voltage of the battery pack is higher than the maximum charging voltage of a charging source to be set, the battery pack cannot be charged.
Against this background, the present invention seeks to present a method for a charging a modular AC battery. A central control system of this AC battery is intended to be designed/configured so that the AC battery can be adjusted to a respective charging voltage level. A system on which the method is executed is also intended to be presented.
A method for AC charging an AC battery according to a first aspect of the invention is as claimed in claim 1, in which the AC battery comprises a central controller and three strings each having at least two battery modules. A respective battery module of the respectively at least two battery modules has at least one energy store and at least two power semiconductor switches, which connect the respective battery module in series or in parallel or in bypass to another battery module. A respective phase with a phase voltage level is provided by the three strings. The AC battery is charged by a charging source via a charging circuit, wherein an at least single-phase alternating current at a charging voltage level is provided by the charging source and the charging circuit has at least one switch and a filter. A respective state of charge of the energy stores is monitored by the central controller during charging, wherein an instantaneous value of the phase voltage level is adjusted to a time profile of an instantaneous value of the charging voltage level according to a continued evaluation of the respective states of charge of the energy stores and by a dynamic driving of the power semiconductor switches, and the AC battery is configured by interconnection of the strings with one another and with respect to a reference potential according to a comparison between the phase voltage level and the charging voltage level in such a way that an output voltage level of the AC battery is greater than or equal to the charging voltage level.
The phase voltage level results directly in a voltage between two phases, which is referred to as outer conductor voltage by a person skilled in the art. In the case of a three-phase sinusoidal alternating current, the ratio between phase voltage level and outer conductor voltage level is one to root three.
The filter of the charging circuit suppresses an inrush current caused by a voltage difference between the AC battery and the charging source. The voltage difference can arise, for example, due to a changing charging current of an uncontrolled charging source or at the moment of connection of the charging circuit to the charging source. Here, the filter also has the task of filtering out instances of electromagnetic interference.
It is also conceivable that the AC battery uses a phase lock loop (abbreviated to PLL) in order to prevent a surge current when the charging source or EVSE is switched over to the electric vehicle or EV. The terminal voltage of the AC battery is set to an instantaneous value of the charging voltage during the charging process.
An AC battery in accordance with the method according to the invention is described, for example, in "Goetz, S.M.; Peterchev, A.V.; Weyh, T., "Modular Multilevel Converter With Series and Parallel Module Connectivity: Topology and Control", Power Electronics, IEEE Transactions on, vol.30, no.1, pp. 203, 215, 2015. doi: 10.1109fTPEL.2014.2310225. Such an AC battery can interconnect respective battery modules in series, in parallel or in bypass with adjacent battery modules and thus actively set a terminal voltage between a negative and a positive of a maximum voltage specified by a number of battery modules (and the respective included energy store) per string. In addition, beyond the terminal voltage resulting from a series or parallel interconnection or possible combinations, an arbitrary (absolute) value of up to the maximum voltage resulting on average over time can be produced by way of high-frequency switchover or connection and disconnection of individual battery modules, with the electric motor as low-pass filter. The setting process is carried out by the control program on the central controller, which controls the series/parallel/bypass interconnection of the battery modules taking into account the respective states of the energy stores in such a way that, for example, a function of a power factor correction is carried out and a circuit present to this effect in conventional OBCs (on-board chargers) is omitted, as a result of which the control program carrying out the method according to the invention or the central controller advantageously have a lower space requirement and lower production costs than a conventional OBC. If the phase voltage level of the AC battery is higher than the charging voltage level, the AC battery can control the charging current. This can be implemented both in the case of single-phase charging as well as in the case of three-phase charging.
In one embodiment of the method according to the invention, a single-phase alternating current of the at least single-phase alternating current is provided by the charging source. In the event that the charging voltage level is lower than the phase voltage level of the AC battery, a respective phase output of the three strings is reconfigured to form a single phase output and the AC battery is charged from the charging source directly via the filter. The three-phase AC battery is thus treated like a single-phase AC battery. Furthermore, in the event that the charging voltage level is lower than a voltage level between two phases of the AC battery but greater than the phase voltage level of the AC battery or equal to the phase voltage level of the AC battery, an input of a first string of the three strings is connected to the reference potential and a phase output of the first string of the three strings is connected to the respective input of the two other strings of the three strings, and also the respective phase output of the two other strings of the three strings is reconfigured to form a single phase output of the AC battery and the AC battery is charged from the charging source directly via the filter. The three-phase AC battery is thus charged in a phase-to-phase manner. Furthermore, in the event that the charging voltage level is lower than twice the voltage level between two phases of the AC battery but greater than or equal to the voltage level between two phases of the AC battery, the input of the first string of the three strings is connected to the reference potential and the phase output of the first string of the three strings is connected in parallel with the respective input of the two other strings of the three strings, and also the respective phase output of the two other strings of the three strings is reconfigured to form a single phase output of the AC battery, a single-phase rectifier is additionally arranged between the single phase output and the filter and the AC battery is charged from the charging source via the single-phase rectifier and the filter.
In another embodiment of the method according to the invention, a three-phase alternating current of the at least single-phase alternating current is provided by the charging source. In the event that the charging voltage level is lower than the phase voltage level of the AC battery, a respective phase output of the three strings is connected to form a respective phase output of the charging source and the AC battery is charged from the charging source directly via the filter. The three-phase AC battery is thus treated like a single-phase AC battery. Furthermore, in the event that the charging voltage level is lower than twice the phase voltage level of the AC battery but greater than or equal to the phase voltage level of the AC battery, a three-phase rectifier is additionally arranged between the respective phase outputs and the filter and the AC battery is charged from the charging source via the three-phase rectifier and the filter.
The method according to the invention thus presents various charging techniques using the reconfigurable AC battery and advantageously expands a range of charging voltage levels at which charging can be performed. The AC battery is able to control the flow of current from the charging source or charging column by way of the configuration of the AC battery, said configuration being assigned to the respective charging voltage level.
In a further embodiment of the method according to the invention, the central controller comprises a hardware-programmable processor unit on which a control program for driving the AC battery is configured at the beginning of operation. By way of example, an FPGA can be selected for such a processor unit. FPGA is an acronym for Field-Programmable Gate Array. For example, on starting or beginning the operation of the electric vehicle, for the driving of the AC battery in accordance with the invention executed by the central controller, a respective processor programming can be configured on the FPGA, said programming being applicable as hardware implementation and being able to be executed in an appropriately reliable manner. The FPGA can advantageously be connected to a microcontroller or the FPGA can additionally comprise a microcontroller. In a further continued embodiment, it is also conceivable for the central controller to be implemented on a microcontroller or an "Application-Specific Integrated Circuit" or ASIC. A combination of a microcontroller and an FPGA/ASIC represents a further advantageous embodiment.
In yet another embodiment of the method according to the invention, the charging circuit is controlled by a charging controller. The charging controller comprises a hardware-programmable processor unit on which a control program for driving the charging circuit is configured at the beginning of operation.
The single-phase or three-phase rectifier can comprise at least two semiconductor switches controlled by the charging controller as active electrical components. The semiconductor switches can preferably be IGBTs, MOSFETs or ICGTs. This increases the efficiency but also the complexity of the charging circuit.
In still another embodiment of the method according to the invention, the single-phase or three-phase rectifier comprises passive and active electrical components and combines these with respect to maximum efficiency by way of the charging controller. Such an optimum combination has the greatest possible efficiency with the smallest degree of complexity.
In still another embodiment of the method according to the invention, a charging power is controlled by way of a dynamic actuation of the power semiconductor switches. In addition to the information about the states of charge of the energy stores, the values of a charging voltage and a charging current are also provided to the charging controller, whereby the central controller actuates the power semiconductor switches of the AC battery in such a way that a prescribed value of a charging power formed from the product of the charging voltage and the charging current is retained.
A further advantage of the method according to the invention is that demands on a DC voltage ripple of a charging current applied to the AC battery can be defined within greater limits than in the case of a conventional battery. A DC voltage ripple of the charging current provided by the rectifier may be determined, for example, by high-frequency fluctuations (ripple) of the alternating current provided by the charging source. The fact that the control program of the central controller that carries out the method according to the invention ascertains this by way of measurement apparatuses, which measure the charging voltage and/or the charging current, and reacts thereto by a continued variation of the series-parallel interconnection of the battery modules and the terminal voltage that changes as a result thereof, in order to provide at any given moment optimum charging conditions, such as, for example, a lower or equal terminal voltage compared to the charging voltage. The continued changing of the series-parallel interconnection is in this case implemented again at a specified switching clock, wherein the switching clock is selected to be small enough in order to be able to follow changes in the alternating current provided by the charging source.
Furthermore, in a second aspect of the invention a system for AC charging an AC battery is proposed as claimed in claim 6, in which the AC battery comprises a central controller and three strings each having at least two battery modules. A respective battery module of the respectively at least two battery modules has at least one energy store and at least two power semiconductor switches, which connect the respective battery module in series or in parallel or in bypass to another battery module. The three strings are designed/configured to provide a respective phase with a respective phase voltage level. A charging circuit is designed/configured to charge the AC battery from a charging source and to provide an at least single-phase alternating current with a charging voltage level, wherein the charging circuit has at least one switch and a filter. The central controller is designed/configured to monitor a respective state of charge of the energy stores during charging and to adjust an instantaneous value of the phase voltage level to a time profile of an instantaneous value of the charging voltage level according to a continued evaluation of the respective states of charge of the energy stores and by a dynamic driving of the power semiconductor switches. The central controller is additionally designed/configured to configure the AC battery by interconnection of the strings with one another and with respect to a reference potential according to a comparison between the phase voltage level and the charging voltage level in such a way that an output voltage level of the AC battery is greater than or equal to the charging voltage level.
In one configuration of the system according to the invention, a single-phase alternating current of the at least single-phase alternating current is provided by the charging source. In the event that the charging voltage level is lower than the phase voltage level of the AC battery, the system is designed/configured to reconfigure a respective phase output of the three strings to form a single phase output of the AC battery and to charge the AC battery from the charging source directly via the filter. In the event that the charging voltage level is lower than a voltage level between two phases of the AC battery but greater than or equal to the phase voltage level of the AC battery, the system is designed/configured to connect an input of a first string of the three strings to the reference potential and to connect a phase output of the first string of the three strings in parallel with a respective input of the two other strings of the three strings, and also to reconfigure the respective phase output of the two other strings of the three strings to form the single phase output of the AC battery and to charge the AC battery from the charging source directly via the filter. In addition, in the event that the charging voltage level is lower than twice the voltage level between two phases of the AC battery but greater than the voltage level between two phases of the AC battery or equal to the voltage level between two phases of the AC battery, the system is designed/configured to connect the input of the first string of the three strings to the reference potential and to connect the phase output of the first string of the three strings in parallel with the respective input of the two other strings of the three strings, and also to reconfigure the respective phase output of the two other strings of the three strings to form the single phase output of the AC battery, to additionally arrange a single-phase rectifier between the single phase output of the AC battery and the filter and to charge the AC battery from the charging source via the single-phase rectifier and the filter.
In another configuration of the system according to the invention, a three-phase alternating current of the at least single-phase alternating current is provided by the charging source. In the event that the charging voltage level is lower than the phase voltage level of the AC battery, the system is designed/configured to connect the respective phase output of the three strings to form a respective phase output of the charging source and to charge the AC battery from the charging source directly via the filter. Furthermore, in the event that the charging voltage level is lower than twice the phase voltage level of the AC battery but greater than the phase voltage level or equal to the phase voltage level of the AC battery, the system is designed/configured to additionally arrange a three-phase rectifier between the respective phase outputs of the AC battery and the filter and to charge the AC battery from the charging source via the three-phase rectifier and the filter.
In a further configuration of the system according to the invention, the central controller comprises a hardware-programmable processor unit, on which a control program for actuating the AC battery is configured at the beginning of operation.
In yet another configuration of the system according to the invention, the charging circuit is controlled by a charging controller. The charging controller comprises a hardware-programmable processor unit on which a control program for driving the charging circuit is configured at the beginning of operation.
In one configuration of the system according to the invention, the processor unit is an FPGA and the finite-state machine is realized by way of the control program with the aid of a VHDL module on the FPGA as hardware program.
Further advantages and configurations of the invention emerge from the description and from the appended drawing.
It is understood that the features mentioned above and the features yet to be discussed below may be used not only in the respectively specified combination but also in other combinations or individually without departing from the scope of the present invention.
The figures are described cohesively and comprehensively and the same components are assigned the same reference symbols.
Figure 1 shows a circuit diagram for an AC battery according to the prior art.
Figure 2 shows a circuit diagram for a single-phase charging process at a charging voltage level lower than a phase voltage level in one embodiment of the method according to the invention.
Figure 3 shows a circuit diagram for a single-phase charging process at a charging voltage level lower than a outer conductor voltage in another embodiment of the method according to the invention.
Figure 4 shows a circuit diagram for a single-phase charging process at a charging voltage level lower than twice a outer conductor voltage in yet another embodiment of the method according to the invention.
Figure 5 shows a circuit diagram for a three-phase charging process at a charging voltage level lower than a phase voltage level in another embodiment of the method according to the invention.
Figure 6 shows a circuit diagram for a three-phase charging process at a charging voltage level lower than twice a phase voltage level in yet another embodiment of the method according to the invention.
Figure 1 shows a circuit diagram 100 for an AC battery 110 according to the prior art. The AC battery 110 has three strings 111, 112, 113 each having battery modules interconnected in series, wherein a respective battery module has at least one energy store and power semiconductor switches. The power semiconductor switches can interconnect the at least one energy store of the respective battery module in series or in parallel with the at least one energy store of an adjacent battery module or bypass the at least one energy store of the respective battery module. The respective strings 111, 112, 113 each have two input connections and two output connections, wherein the respective first input connections are combined at a first zero point 103, which is connected to a reference potential 101. The respective second input connections are combined at a second zero point 104. The respective two output connections are combined to form a respective single phase output of the three strings 111, 112, 113. While the AC battery 110 has a phase voltage level 102, an outer conductor voltage 105 is present between two respective strings 111, 112, 113, for example between string 112 and string 111.
Figure 2 shows a circuit diagram 200 for a single-phase charging process at a charging voltage level 221 lower than the phase voltage level 102 in one embodiment of the method according to the invention. A charging source or a charging column 220 that provides a single-phase alternating current has the charging voltage level 221 to the reference potential 201. The charging source 220 is connected for this purpose to a power grid, for example. A charging circuit comprises a charging switch 206, which is closed for charging the battery 110, and a filter 230. The three strings 111, 112, 113 of the AC battery 110 are combined to form a single phase output.
Figure 3 shows a circuit diagram 300 for a single-phase charging process in a further embodiment of the method according to the invention. In this case, a charging voltage level 321 provided by a charging source 320 is greater than or equal to the phase voltage level 102 of the AC battery 110 from fig. 1 or fig. 2, but is lower than the outer conductor voltage 105 thereof The reconfiguration according to the invention produces an AC battery 310 in which an input of a first string 311 is connected to the reference potential 101. Respective inputs of the two other strings 312, 313 are connected to both outputs of the first string 311, with the result that the two other strings 312, 313 are connected in parallel. The respective outputs thereof are connected to form a single-phase output 303 of the AC battery 310. The AC battery 310 has a voltage of 302 at the level of the outer conductor voltage 105 of the AC battery 110 from fig. 1, which in this example is higher than the charging voltage level 321 and thus the AC battery 310 or the central controller thereof advantageously makes it possible to control the charging current.
Figure 4 shows a circuit diagram 400 for a single-phase charging process in yet another embodiment of the method according to the invention. In this case, a charging voltage level 421 provided by a charging source 420 is greater than or equal to the outer conductor voltage 105 of the AC battery 110 from fig. 1, but is lower than twice said outer conductor voltage 105. In addition to the reconfiguration according to the invention presented in fig. 3 with respect to the AC battery 310, a rectifier 440 is arranged, which restricts the charging voltage of the charging source 420 to positive values and thus halves the charging voltage level 421 with respect to the reference potential 101. A charging voltage applied to the single-phase output 303 of the AC battery 310 is lower than a voltage level 302 of the AC battery 310 (which corresponds to the outer conductor voltage 105 of the AC battery 110 from fig. 1), and thus advantageously makes it possible for the AC battery 310 to control the charging current.
Figure 5 shows a circuit diagram 500 for a three-phase charging process in another embodiment of the method according to the invention. A charging voltage level provided by a three-phase charging source 520 is lower than the phase voltage level 102 of the AC battery 110 from fig. 1, whose respective string outputs are combined to form a respective phase output 511, 512, 513. These phase outputs 511, 512, 513 of the AC battery 110 are each connected to corresponding phase outputs 521, 522, 523 of the charging source 520 directly via the filter 530 when the charging switch 506 is closed. Since the charging level provided by the three-phase charging source 520 is lower than the phase voltage level 102 of the AC battery 110 from fig. 1, the AC battery 110 can control the charging current, for which reason components of an (on-board) charging circuit known from the prior art, such as rectifiers, power factor correction filters or DC converters, for example, are advantageously omitted.
Figure 6 shows a circuit diagram 600 for a three-phase charging process in yet another embodiment of the method according to the invention. In this case, a charging voltage level provided by the charging source 620 is lower than twice the phase voltage level 102 of the AC battery 110 from fig. 1 but greater than or equal to the phase voltage level 102 of the AC battery 110 of fig. 1. The respective phase outputs 611, 612, 613 of the AC battery 110 are connected to the corresponding phase outputs 621, 622, 623 of the charging source 620 via a rectifier 640 arranged in addition compared to fig. 5. Since the rectifier 640 restricts the charging voltage of the charging source 620 to positive values and thus halves the charging voltage level thereof with respect to the reference potential 101, a situation in which a charging voltage applied to the respective phase outputs 611, 612, 613 of the AC battery 110 is lower than a phase voltage 102 of the AC battery 110 from fig. 1 is achieved, as a result of which the charging current can advantageously be controlled by the AC battery.

Claims (10)

  1. Patent claims 1. A method for AC charging an AC battery, in which the AC battery comprises a central controller and three strings each having at least two battery modules, wherein a respective battery module of the respectively at least two battery modules has at least one energy store and at least two power semiconductor switches, which connect the respective battery module in series or in parallel or in bypass to another battery module, wherein a respective phase with a phase voltage level is provided by the three strings, wherein the AC battery is charged by a charging source via a charging circuit, wherein an at least single-phase alternating current at a charging voltage level is provided by the charging source, wherein the charging circuit has at least one switch and a filter, wherein a respective state of charge of the energy stores is monitored by the central controller during charging, wherein an instantaneous value of the phase voltage level is adjusted to a time profile of an instantaneous value of the charging voltage level according to a continued evaluation of the respective states of charge of the energy stores and by a dynamic driving of the power semiconductor switches, and wherein the AC battery is configured by interconnection of the strings with one another and with respect to a reference potential according to a comparison between the phase voltage level and the charging voltage level in such a way that an output voltage level of the AC battery is greater than or equal to the charging voltage level.
  2. 2. The method as claimed in claim 1, in which a single-phase alternating current of the at least single-phase alternating current is provided by the charging source and in which * in the event that the charging voltage level is lower than the phase voltage level, a respective phase output of the three strings is reconfigured to form a single phase output and the AC battery is charged from the charging source directly via the filter, * in the event that the charging voltage level is lower than a voltage level between two phases of the AC battery but greater than or equal to the phase voltage level, an input of a first string of the three strings is connected to the reference potential and at a phase output of the first string of the three strings is connected in parallel with a respective input of the two other strings, and also the respective phase output of the two other strings of the three strings is reconfigured to form a single phase output of the AC battery and the AC battery is charged from the charging source directly via the filter, or * in the event that the charging voltage level is lower than twice the voltage level between two phases of the AC battery but greater than or equal to the voltage level between two phases of the AC battery, the input of the first string of the three strings is connected to the reference potential and the phase output of the first string of the three strings is connected in parallel with the respective input of the two other strings of the three strings, and also the respective phase output of the two other strings of the three strings is reconfigured to form the single phase output of the AC battery, a single-phase rectifier is additionally arranged between the single phase output and the filter and the AC battery is charged from the charging source via the single-phase rectifier and the filter.
  3. 3. The method as claimed in claim 1, in which a three-phase alternating current of the at least single-phase alternating current is provided by the charging source and in which * in the event that the charging voltage level is lower than the phase voltage level of the AC battery, a respective phase output of the three strings is connected to form a respective phase output of the charging source and the AC battery is charged from the charging source directly via the filter, or * in the event that the charging voltage level is lower than twice the phase voltage level of the AC battery but greater than or equal to the phase voltage level of the AC battery, a three-phase rectifier is additionally arranged between the respective phase outputs and the filter and the AC battery is charged from the charging source via the three-phase rectifier and the filter.
  4. 4. The method as claimed in any one of the preceding claims, in which the central controller has a hardware-programmable processor unit on which a control program for driving the AC battery is configured at the beginning of operation.
  5. 5. The method as claimed in any one of the preceding claims, in which the charging circuit is controlled by a charging controller, wherein the charging controller has a hardware-programmable processor unit on which a control program for driving the charging circuit is configured at the beginning of operation.
  6. 6. A system for AC charging an AC battery, in which the AC battery comprises a central controller and three strings each having at least two battery modules, wherein a respective battery module of the respectively at least two battery modules has at least one energy store and at least two power semiconductor switches, which connect the respective battery module in series or in parallel or in bypass to another battery module, wherein the three strings are designed to provide a respective phase with a respective phase voltage level, wherein a charging circuit is designed to charge the AC battery from a charging source and to provide an at least single-phase alternating current with a charging voltage level, wherein the charging circuit has at least one switch and a filter, wherein the central controller is designed to monitor a respective state of charge of the energy stores during charging and to adjust an instantaneous value of the phase voltage level to a time profile of an instantaneous value of the charging voltage level according to a continued evaluation of the respective states of charge of the energy stores and by a dynamic driving of the power semiconductor switches, and wherein the central controller is additionally designed to configure the AC battery by interconnection of the strings with one another and with respect to a reference potential according to a comparison between the phase voltage level and the charging voltage level in such a way that an output voltage voltage level of the AC battery is greater than or equal to the charging voltage level.
  7. 7. The system as claimed in claim 6, in which a single-phase alternating current of the at least single-phase alternating current is provided by the charging source and in which the system is designed * in the event that the charging voltage level is lower than the phase voltage level, to reconfigure a respective phase output of the three strings to form a single phase output of the AC battery and to charge the AC battery from the charging source directly via the filter, * in the event that the charging voltage level is lower than a voltage level between two phases of the AC battery but greater than or equal to the phase voltage level, to connect an input of a first string of the three strings to the reference potential and to connect a phase output of the first string of the three strings in parallel with the respective input of the two other strings of the three strings, and also to reconfigure the respective phase output of the two other strings of the three strings to form the single phase output of the AC battery and to charge the AC battery from the charging source directly via the filter, and * in the event that the charging voltage level is lower than twice the voltage level between two phases of the AC battery but greater than or equal to the voltage level between two phases of the AC battery, to connect the input of the first string of the three strings to the reference potential and to connect the phase output of the first string of the three strings in parallel with the respective input of the two other strings of the three strings, and also to reconfigure the respective phase output of the two other strings of the three strings to form the single phase output of the AC battery, to additionally arrange a single-phase rectifier between the single phase output and the filter and to charge the AC battery from the charging source via the single-phase rectifier and the filter.
  8. 8. The system as claimed in claim 6, in which a three-phase alternating current of the at least single-phase alternating current is provided by the charging source (520, 620) and in which the system is designed * in the event that the charging voltage level is lower than the phase voltage level of the AC battery, to connect a respective phase output of the three strings to form a respective phase output of the charging source and to charge the AC battery from the charging source directly via the filter, * in the event that the charging voltage level is lower than twice the phase voltage level of the AC battery but greater than or equal to the phase voltage level of the AC battery, to additionally arrange a three-phase rectifier between the respective phase outputs and the filter and to charge the AC battery from the charging source via the three-phase rectifier and the filter.
  9. 9. The system as claimed in any one of claims 6 to 8, in which the central controller comprises a hardware-programmable processor unit on which a control program for driving the AC battery is configured at the beginning of operation.
  10. 10. The system as claimed in any one of the claims 6 to 9, in which the charging circuit is controlled by a charging controller, wherein the charging controller comprises a hardware-programmable processor unit on which a control program for driving the charging circuit is configured at the beginning of operation.
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WO2019076479A1 (en) * 2017-10-17 2019-04-25 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Method and apparatus for charging an energy store

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AT508279A1 (en) 2009-05-14 2010-12-15 Net Neue En Technik Gmbh METHOD AND ARRANGEMENT FOR CHARGING BATTERIES
DE102010052934B4 (en) 2010-11-30 2024-07-25 Technische Universität München New multilevel converter topology with the possibility of dynamic serial and parallel connection of individual modules
US9114794B2 (en) 2013-03-13 2015-08-25 Ford Global Technologies, Llc Method and system for controlling an electric vehicle while charging
DE102015106196B3 (en) 2015-04-02 2016-06-23 Rainer Marquardt Low loss modular multilevel converter
DE102017124125A1 (en) * 2017-10-17 2019-04-18 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Charging an energy storage

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* Cited by examiner, † Cited by third party
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WO2019076479A1 (en) * 2017-10-17 2019-04-25 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Method and apparatus for charging an energy store
US20210197676A1 (en) * 2017-10-17 2021-07-01 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Method and apparatus for charging an energy store

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