Method and system for controlling semiconductor switches in a modular battery

Abstract

The present invention relates to a method for controlling semiconductor switches in a modular battery, wherein the modular battery comprises a plurality of battery modules (121, 122, 129) arranged in at least one string, each of which has a plurality of semiconductor switches and at least one energy storage device, a central controller (101), and a plurality of transmission channels (102) between the central controller and the battery modules, wherein switching commands for providing at least one AC phase are transmitted from the central controller to the battery modules by transmitting a switching position associated with a respective semiconductor switch to each battery module for each switching cycle, assigning a separate transmission channel to each battery module, and in a serialization unit (111, 112, 119) assigned to the respective battery module, the respective switching positions (131, 132, 133,139) are combined into a serial message, the respective serial message is transmitted via the respective transmission channel to the respective battery module, where it is decomposed into the respective switching states by a deserialization unit (103), and these are converted by the respective semiconductor switches. Furthermore, a transmission system on which the procedure is carried out is presented.

Description

[0001] The present invention relates to a method for controlling semiconductor switches in a modular battery. Furthermore, a system on which the method is implemented is presented.

[0002] A modular battery is used in electric vehicles to supply power to a traction system. Each battery module has an energy storage device or a DC voltage source, whereby one or more phases for supplying AC power to a traction motor are generated by continuously alternating interconnection of the battery modules. Such a modular battery can be implemented using a modular multilevel converter system, for example, as described in "Goetz, SM; Peterchev, AV; 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: 10.1109 / TPEL.2014.2310225."

[0003] The energy storage device in the individual battery module is connected to the respective input and output terminals via half-bridges of semiconductor switches, e.g., MOSFETs. Depending on the design, the battery module can assume various switching states, such as "serial," "parallel," or "bypass," which each indicates the connection of the respective energy storage device within the string of battery modules. Each switching state then corresponds to a fixed configuration of switching positions of the semiconductor switches in the half-bridges.

[0004] At each switching cycle, the central controller sends a switching command to each battery module, specifying the switching state it is to assume. This command is transmitted in coded form via a high-speed bus to the respective battery module. The respective battery module then uses the switching command to calculate the switching positions its semiconductor switches must assume. In addition, the respective battery module must identify possible transmission errors and complete further safety checks. In order to implement this in real time (command cycle of, for example, seven microseconds on the high-speed bus), a high level of computing power is required, which requires a corresponding processor unit on both the central controller and each individual battery module that is capable of handling this computing power. This requirement is met, for example, bya so-called "Field Programmable Gate Array," abbreviated to FPGA. The high-speed bus required for command transmission can be designed, for example, according to an RS-485 protocol.

[0005] The aforementioned high communication requirements between the central controller and the battery modules are also required by the fact that, depending on the configuration of the battery modules, the connection of the respective energy storage unit must be synchronous to the respective energy storage unit of a neighboring battery module in order to avoid short-circuit scenarios.

[0006] In contrast, there are transmission methods which, for example, in video transmission, represent a standard for high-speed data transmission methods, such as the so-called “Low Voltage Differential Signaling”, also abbreviated as LVDS.

[0007] The document US 2012 / 0280694 A1 discloses a battery system in which measurement data is transmitted via LVDS.

[0008] The document DE 10 2013 104 326 A1 discusses a lithium-ion cell system in which data is transmitted between a display port and a storage control network node using LVDS.

[0009] The document DE 10 2014 101 391 A1 describes a battery module which comprises a capacitive communication level circuit with LVDS devices.

[0010] The document DE 10 2011 054 370 A1 deals with a battery simulation device in which target values ​​are transmitted to a control unit via an LVDS interface.

[0011] Against this background, it is an object of the present invention to present a method for controlling a modular battery that ensures real-time control of the battery modules of the modular battery. The high computing power requirements of the individual battery modules for implementing the control are to be avoided. Furthermore, a system on which the method is implemented is to be presented.

[0012] To achieve the above-mentioned object, a method for controlling semiconductor switches in a modular battery is proposed, wherein the modular battery comprises a plurality of battery modules arranged in at least one string, each of which has a plurality of semiconductor switches and at least one energy storage device, a central controller, and a plurality of transmission channels between the central controller and the battery modules. The central controller transmits switching commands for providing at least one alternating current phase to the plurality of battery modules via the plurality of transmission channels, by • each battery module is transmitted a switching position assigned to a respective semiconductor switch of the battery module for each switching cycle, • each battery module is assigned its own transmission channel from the plurality of transmission channels, • in a serialization unit assigned to the respective battery module, the respective switching positions are summarized into a serial message for each switching cycle, • the respective serial message is transmitted to the respective battery module via the respective transmission channel, • and is broken down into the respective switching positions by a deserialization unit arranged in the respective battery module and these are implemented by the respective semiconductor switches.

[0013] The method according to the invention thus advantageously enables the transmission of pure switching states, which are realized, for example, by a set bit "1" for a closed switching position and a non-set bit "0" for an open switching position of the semiconductor switch. If the semiconductor switches are formed by MOSFETs, the transmitted bit corresponds exactly to the gate signal and can thus be connected directly from the deserialization unit to the respective gate. This advantageously eliminates the decoding effort required by the respective battery module to convert a respective switching command from the central controller related to a switching state into the respective switching positions of its semiconductor switches.When applying the method according to the invention, any control effort remaining on the respective battery module can advantageously already be handled by a microcontroller, and is thus more cost-effective compared to an FPGA, while maintaining real-time capability.

[0014] In one embodiment of the method according to the invention, low-voltage differential signaling is used to transmit the respective serially written message. Such a standard, known from the prior art, offers established and cost-effective serialization / deserialization units that ensure a deterministic process for the assembly / decomposition of the respective serially written message. For feedback from a respective battery module to the central controller, an error loop can be arranged, for example. However, it is also conceivable that transmission means intended for such a purpose could be used in the serialization / deserialization units.

[0015] In a further embodiment of the method according to the invention, an equal number of serialization units are arranged on the central controller, corresponding to the number of battery modules. For each switching cycle, the respective switching positions are supplied to the respective serialization unit by a scheduler of the central controller.

[0016] In another embodiment of the method according to the invention, the central controller encodes an equal number of switching states, corresponding to the respective switching positions of semiconductor switches of the respective battery module, into a high-speed bus message and transmits it via a high-speed bus to at least one decoder. A decoding unit and a series of serialization units are arranged in the at least one decoder. The decoding unit decodes the high-speed bus message by determining the respective switching positions of the semiconductor switches of those battery modules assigned to the series of serialization units according to the respective switching states. The respective switching positions are fed to the series of serialization units.

[0017] In a further embodiment of the method according to the invention, a number of decoders is selected corresponding to a number of strings with battery modules. The number of serialization units per respective decoder is selected corresponding to a number of battery modules per respective string.

[0018] Furthermore, a transmission system for controlling semiconductor switches in a modular battery is claimed, wherein the modular battery comprises a plurality of battery modules arranged in at least one string, each of which has a plurality of semiconductor switches and at least one energy storage device, a central controller, and the transmission system. The transmission system is arranged between the central controller and the battery modules and comprises a plurality of serialization units, a plurality of deserialization units, and a plurality of transmission channels. The transmission system is designed to transmit switching commands for providing at least one alternating current phase from the central controller to the plurality of battery modules via the plurality of transmission channels by • each battery module is transmitted a switching position assigned to a respective semiconductor switch of the battery module for each switching cycle, • each battery module is assigned its own transmission channel of at least one transmission channel, • in a serialization unit assigned to the respective battery module, the respective switching positions are summarized into a serial message for each switching cycle, • the respective serial message is transmitted to the respective battery module via the respective transmission channel, • and is broken down into the respective switching positions by a deserialization unit arranged in the respective battery module and these are implemented by the respective semiconductor switches.

[0019] In one embodiment of the transmission system according to the invention, it is designed to use low-voltage differential signaling to transmit the respective serially composed message.

[0020] In a further embodiment of the transmission system according to the invention, an equal number of serialization units are arranged on the central controller, corresponding to the number of battery modules. For each switching cycle, the respective switching positions are supplied to the respective serialization unit by a scheduler of the central controller.

[0021] In another embodiment of the transmission system according to the invention, the transmission system additionally comprises a high-speed bus and at least one decoder with a decoding unit and a series of serialization units of the plurality of serialization units.The transmission system is designed to transmit a high-speed bus message, in which a number of switching states corresponding to respective switching positions of semiconductor switches of the respective battery module is encoded and is formed by the central controller according to the number of battery modules, to at least one decoder via a high-speed bus, to decode the high-speed bus message by the decoding unit, wherein the respective switching positions of the semiconductor switches of the battery modules assigned to the series of serialization units are determined according to the respective switching states, and to supply the respective switching positions to the series of serialization units.

[0022] In a further embodiment of the transmission system according to the invention, a number of decoders is selected corresponding to a number of strings with battery modules. The number of serialization units per respective decoder is selected corresponding to a number of battery modules per respective string.

[0023] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0024] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention. Fig. 1 shows schematically an embodiment of the transmission system according to the invention. Fig. 2 shows schematically a further embodiment of the transmission system according to the invention.

[0025] In Fig. 1 schematically shows an embodiment 100 of the transmission system according to the invention. On a central controller 101, an equal number N of serialization units 111, 112, 119 are arranged, corresponding to a number N of battery modules 121, 122, 129. At each switching cycle, a processor or scheduler 110 of the central controller 101 supplies the respective switching positions 131, 132, 133, 139 for all M semiconductor switches in a battery module 121, 122, 129 assigned to the respective serialization unit 111, 112, 119. Via N transmission channels 102, e.g. using low-voltage differential signaling (LVDS), a message containing the respective switching positions 131, 132, 133, 139, which is serially composed by the respective serialization unit 111, 112, 119, is transmitted to the respective battery module 121, 122, 129. For example,a modular battery with N=18 battery modules 111, 112, 119, i.e. a first battery module 111, a second battery module 112, and up to an 18th battery module 119, and each battery module 111, 112, 119 has, for example, M=8 semiconductor switches, then, for example, the first serialization unit 111 for M=8 semiconductor switches is assigned correspondingly eight switching positions 131, 132, 133, 139. Each serialization unit 111, 112, 119 has a dedicated transmission channel 102 to the respective battery module 121, 122, 129, wherein a deserialization unit 103 is arranged in each of the battery modules 121, 122, 129 in order to break down the transmitted message into respective switching positions 131, 132, 133, 139 and to supply it to the respective gate drivers.

[0026] In Fig. 2 schematically shows a further embodiment 200 of the transmission system according to the invention. The central controller 201 transmits respective switching states as a high-speed bus message via a high-speed bus 202 to a respective decoder 231, 232, 239. Each decoder 231, 232, 239 is assigned to a respective AC phase formed by a respective string of battery modules 221, 222, 229. The respective decoder 231, 232, 239 has a respective decoding unit 203, which converts the high-speed bus message into individual switching positions 131, 132, 133, 139 corresponding to the respective switching states and forwards them to the serialization unit 211, 212, 219 arranged according to a number K of battery modules per string. The number K of battery modules per string is calculated by dividing the total number N of battery modules by the number of strings formed.Each serialization unit 211, 212, 219 is connected to the corresponding battery module 221, 222, 229 with a respective transmission channel 102 and thus transmits the serially composed message with the switching positions 131, 132, 133, 139, whereupon analogously to . Fig. 1 procedure is followed. List of reference symbols 100 transmission scheme 101 Central Controller 102 transmission channel for serial message using LVDS 103 Deserialization unit 110 Processor (Scheduler) 111 Serialization unit for first module 112 Serialization unit for second module 119 Serialization unit for Nth module 121 First Module 122 Second Module 129 Nth module 131 Gate Command 1 132 Gate Command 2 133 Gate Command 3 139 Gate command M 141 First gate driver 142 Second gate driver 143 Third Gate Driver 149 M-th gate driver 200 transmission scheme with decoding stage 201 Central Controller 202 high-speed bus 203 decoders 211 Serialization unit for first module of the first phase 212 Serialization unit for second module of the first phase 219 Serialization unit for K-th module of the first phase 221 First module of the first phase 222 Second module of the first phase 229 K-th module of the first phase 231 Decoding unit first phase 232 Decoding unit second phase 239 Decoding unit M-th phase QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2012 / 0280694 A1

[0007] DE 10 2013 104 326 A1

[0008] DE 10 2014 101 391 A1

[0009] DE 10 2011 054 370 A1

[0010] Cited non-patent literature

[0000] Goetz, SM; Peterchev, AV; 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: 10.1109 / TPEL.2014.2310225

[0002]

Claims

[1] Method for controlling semiconductor switches in a modular battery, wherein the modular battery comprises a plurality of battery modules (121, 122, 129, 221, 222, 229) arranged in at least one string, each of which has a plurality of semiconductor switches and at least one energy storage device, a central controller (101, 201), and a plurality of transmission channels (102) between the central controller (101, 201) and the battery modules (121, 122, 129, 221, 222, 229), in which switching commands for providing at least one alternating current phase are transmitted from the central controller (101, 201) to the plurality of battery modules (121, 122, 129, 221, 222, 229) via the plurality of transmission channels (102), by • each battery module (121, 122, 129, 221, 222, 229) is transmitted a switching position (131, 132, 133, 139) assigned to a respective semiconductor switch of the battery module (121, 122, 129, 221, 222, 229) for each switching cycle, • each battery module (121, 122, 129, 221, 222, 229) is assigned its own transmission channel (102) of the plurality of transmission channels (102), • in a serialization unit (111, 112, 119, 211, 212, 219) assigned to the respective battery module (121, 122, 129, 221, 222, 229), the respective switching positions (131, 132, 133, 139) are combined into a serially composed message for each switching cycle, • the respective serially recorded message is transmitted via the respective transmission channel (102) to the respective battery module (121, 122, 129, 221, 222, 229), • and there is broken down into the respective switching positions (131, 132, 133, 139) by a deserialization unit (103) arranged in the respective battery module (121, 122, 129, 221, 222, 229) and these are implemented by the respective semiconductor switches. [2] Method according to claim 1, in which a low-voltage differential signaling is used to transmit the respective serially composed message. [3] Method according to one of the preceding claims, in which an equal number of serialization units (111, 112, 119, 211, 212, 219) are arranged on the central controller (101, 201) corresponding to the number of battery modules (121, 122, 129, 221, 222, 229), in which for each switching cycle the respective switching positions (131, 132, 133, 139) are supplied to the respective serialization unit (111, 112, 119, 211, 212, 219) by a scheduler of the central controller (101, 201). [4] Method according to one of claims 1 or 2, in which the central controller (101, 201) transmits an equal number of switching states corresponding to the number of battery modules (121, 122, 129, 221, 222, 229), which correspond to respective switching positions (131, 132, 133, 139) of semiconductor switches of the respective battery module (121, 122, 129, 221, 222, 229), coded to form a high-speed bus message via a high-speed bus to at least one decoder (231, 232, 239), wherein in the at least one decoder (231, 232, 239) a decoding unit (203) and a series of serialization units (111, 112, 119, 211, 212, 219), in which the high-speed bus message is decoded by the decoding unit (203) by correspondingly changing the respective switching positions (131, 132, 133, 139) of the semiconductor switches of the series of serialization units (111, 112, 119, 211, 212,219) associated battery modules (121, 122, 129, 221, 222, 229), and in which the respective switching positions (131, 132, 133, 139) are fed to the series of serialization units (111, 112, 119, 211, 212, 219). [5] Method according to claim 4, wherein a number of decoders (231, 232, 239) is selected corresponding to a number of strings with battery modules (121, 122, 129, 221, 222, 229), and wherein a number of serialization units (111, 112, 119, 211, 212, 219) per respective decoder (231, 232, 239) is selected corresponding to a number of battery modules (121, 122, 129, 221, 222, 229) per respective string. [6] Transmission system for controlling semiconductor switches in a modular battery, wherein the modular battery comprises a plurality of battery modules (121, 122, 129, 221, 222, 229) arranged in at least one string, each of which has a plurality of semiconductor switches and at least one energy storage device, a central controller (101, 201) and the transmission system, wherein the transmission system is arranged between the central controller (101, 201) and the battery modules (121, 122, 129, 221, 222, 229) and comprises a plurality of serialization units (111, 112, 119, 211, 212, 219), a plurality of deserialization units (103) and a plurality of transmission channels (102), wherein the transmission system is designed to be able to receive from the central controller (101, 201) via the plurality of transmission channels (102) switching commands for providing at least one alternating current phase to the plurality of battery modules (121, 122, 129, 221, 222,229) by, • each battery module (121, 122, 129, 221, 222, 229) is transmitted a switching position (131, 132, 133, 139) assigned to a respective semiconductor switch of the battery module (121, 122, 129, 221, 222, 229) for each switching cycle, • each battery module (121, 122, 129, 221, 222, 229) is assigned its own transmission channel (102) of the plurality of transmission channels (102), • in a serialization unit (111, 112, 119, 211, 212, 219) assigned to the respective battery module (121, 122, 129, 221, 222, 229), the respective switching positions (131, 132, 133, 139) are combined into a serially composed message for each switching cycle, • the respective serially recorded message is transmitted via the respective transmission channel (102) to the respective battery module (121, 122, 129, 221, 222, 229), • and there is broken down into the respective switching positions (131, 132, 133, 139) by a deserialization unit (103) arranged in the respective battery module (121, 122, 129, 221, 222, 229) and these are implemented by the respective semiconductor switches. [7] Transmission system according to claim 6, which is designed to use low-voltage differential signaling to transmit the respective serially composed message. [8] Transmission system according to one of claims 6 or 7, wherein an equal number of serialization units (111, 112, 119, 211, 212, 219) are arranged on the central controller (101, 201) corresponding to the number of battery modules (121, 122, 129, 221, 222, 229), and wherein for each switching cycle, the respective switching positions (131, 132, 133, 139) are supplied to the respective serialization unit (111, 112, 119, 211, 212, 219) by a scheduler of the central controller (101, 201). [9] Transmission system according to one of claims 6 or 7, wherein the transmission system additionally comprises a high-speed bus and at least one decoder (231, 232, 239) with a decoding unit (203) and a series of serialization units (111, 112, 119, 211, 212, 219) of the plurality of serialization units (111, 112, 119, 211, 212, 219), wherein the transmission system is designed to transmit a high-speed bus message in which a number of switching states, which correspond to respective switching positions (131, 132, 133, 139) of semiconductor switches of the respective battery module (121, 122, 129, 221, 222, 229), is encoded and by the central controller (101, 201) corresponding to the number of battery modules (121, 122, 129, 221, 222, 229), to transmit via a high-speed bus to at least one decoder (231, 232, 239), to decode the high-speed bus message by the decoding unit (203),wherein the respective switching positions (131, 132, 133, 139) of the semiconductor switches of the battery modules (121, 122, 129, 221, 222, 229) assigned to the series of serialization units (111, 112, 119, 211, 212, 219) are determined according to the respective switching states, and the respective switching positions (131, 132, 133, 139) are supplied to the series of serialization units (111, 112, 119, 211, 212, 219). [10] A transmission system according to claim 9, wherein a number of decoders (231, 232, 239) is selected according to a number of strings with battery modules (121, 122, 129, 221, 222, 229), and wherein a number of serialization units (111, 112, 119, 211, 212, 219) per respective decoder (231, 232, 239) is selected according to a number of battery modules (121, 122, 129, 221, 222, 229) per respective string.

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