Wireless modular multilevel converter system

Abstract

A multilevel converter for generating alternating current (AC) power includes: an AC bus configured to transmit the AC power; a governing controller; and a plurality of submodules. Each of the submodules: a power converter having a plurality of switching transistors, and a module controller configured to control the plurality of switching transistors to operate in one of a charging mode or an inverter mode. The power converter, in the charging mode, operates to rectify the AC power from the AC bus to supply direct current (DC) power to at least one batten. The power converter, in the inverter mode, operates to generate AC power on the AC bus using the DC power from the at least one battery. Each of the module controllers includes a wireless transceiver configured to communicate with the governing controller using a wireless data interconnection.

Description

[0001]Attorney Docket No.18402-05176 (713271PCT) WIRELESS MODULAR MULTILEVEL CONVERTER SYSTEM CROSS-REFERENCE TO RELATED APPLICATIONS This PCT International Patent Application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 547,266 filed on November 3, 2023, and titled “Wireless Modular Multilevel Converter System,” the entire disclosure of which is hereby incorporated by reference. FIELD The present disclosure relates generally to a modular multilevel power converter system, such as a system for powering electric vehicles (EVs), such as passenger cars and trucks. More specifically, the present disclosure relates to a multilevel power converter system with wireless communications interconnections. BACKGROUND Highly integrated powertrain solutions are being developed and refined by manufacturers of electric vehicles (EVs) to address targets for increasing power density and efficiency. One such highly integrated powertrain topology is the modular multilevel converter (MMC) topology. In a conventional MMC topology, the battery system is subdivided into submodules (SM) that provide voltage steps to create a multi-level voltage excitation for each phase of the machine. In this topology, each SM is equipped with a PCB to fulfill the inverter, DC- DC, and BMS functionalities for its corresponding battery SM. Control circuitry, which may be implemented using printed circuit boards (PCBs), and battery SM may be integrated into a battery housing of the EV. Attorney Docket No.18402-05176 (713271PCT) SUMMARY The present disclosure provides a multilevel converter for generating alternating current (AC) power. The multilevel converter includes: an AC bus configured to transmit the AC power; a governing controller; and a plurality of submodules. Each of the submodules: a power converter having a plurality of switching transistors, and a module controller configured to control the plurality of switching transistors to operate in one of a charging mode or an inverter mode. The power converter, in the charging mode, operates to rectify the AC power from the AC bus to supply direct current (DC) power to at least one battery. The power converter, in the inverter mode, operates to generate AC power on the AC bus using the DC power from the at least one battery. Each of the module controllers includes a wireless transceiver configured to communicate with the governing controller using a wireless data interconnection. The present disclosure also provides an electrified vehicle (EV). The EV includes: a traction motor configured to propel the EV; and a multilevel converter for generating alternating current (AC) power. The multilevel converter includes: an AC bus configured to transmit the AC power; a governing controller; and a plurality of submodules. Each of the submodules: a power converter having a plurality of switching transistors, and a module controller configured to control the plurality of switching transistors to operate in one of a charging mode or an inverter mode. The power converter, in the charging mode, operates to rectify the AC power from the AC bus to supply direct current (DC) power to at least one battery. The power converter, in the inverter mode, operates to generate AC power on the AC bus using the DC power from the at least one battery. Each of the module controllers includes a wireless transceiver configured to communicate with the governing controller using a wireless data interconnection. Attorney Docket No.18402-05176 (713271PCT) BRIEF DESCRIPTION OF THE DRAWINGS Further details, features and advantages of designs of the invention result from the following description of embodiment examples in reference to the associated drawings. FIG.1 shows a schematic block diagram of a system, in accordance with an aspect of the present disclosure; FIG. 2 shows a schematic diagram showing a multilevel power converter, in an aspect of the present disclosure; FIG. 3 shows a schematic block diagram illustrating a multilevel power converter with several controllers having wired data interconnections; and FIG. 4 shows a schematic block diagram illustrating a multilevel power converter with several controllers having wireless data interconnections, and in accordance with and aspect of the present disclosure. DETAILED DESCRIPTION Referring to the drawings, the present invention will be described in detail in view of following embodiments. To overcome the technical limitations of the existing approaches, the present disclosure provides a multilevel power converter with several controllers having wireless data interconnections. The PCBs for each submodule are controlled by a governing controller board that includes the motor control and pack-level balancing of the SMs based on state-of-charge (SoC) and temperature. To establish communication between the main controller and the plurality of SM PCBs a wired connection is required with a given communication protocol. The solutions of the present disclosure provide several benefits and advantages over power converters with conventional, wired, communications. Advantages provided by the present Attorney Docket No.18402-05176 (713271PCT) disclosure include: Reduced cabling cost; weight savings; increased fault tolerance; increased reliability; ease of scalability; ease of installation, service, and repair; and increased electrical isolation between high voltage (HV) and low voltage (LV) components. Reliability may be increased, for example, by removing wiring that can be subject to mechanical wear and / or failure. The use of a wireless network may improve fault tolerance. For example, a fault in a conventional wired daisy chain may disrupt an entire communication network. In a wireless network, if one node fails, the others are still capable of operating properly. This complements the modular multilevel converter architecture’s ability for the system to operate with individual failed modules. The system of the present disclosure provides a scalable design that may accommodate any number of submodules. Changing a number and / or configuration of submodules may only require software updates in the main controller. FIG. 1 shows a block diagram of system 10 in accordance with an aspect of the present disclosure. The system 10 is provided in a vehicle 12 having four wheels 14. The system 10 includes an inverter 20 having at least three pairs of solid-state switches 22, such as field effect transistors (FETs) configured to switch current from a DC power supply 23 and to generate an AC power upon a set of motor leads 24. The motor leads 24 transmit electrical power between the inverter 20 and an electric motor 26. The electric motor 26 may be a permanent magnet synchronous motor (PMSM). The electric motor 26 may be used as a motor, a generator, or as a motor / generator that functions as both a motor and a generator. The electric motor 26 may be configured as a traction motor that is coupled to one or more of the wheels 14 of the vehicle 12 for driving the vehicle 12. Alternatively, the electric motor 26 may be used for one or more ancillary functions in the vehicle 12, such as for operating an actuator, a fan, a pump, etc. In some Attorney Docket No.18402-05176 (713271PCT) embodiments, the system 10 of the present disclosure may have a non-vehicular application, such as for motor control in industrial or manufacturing applications. A first current sensor 28a is arranged to measure current in one of the motor leads 24, and a second current sensor 28b is arranged to measure current in another one of the motor leads 24. In some embodiments, and as shown on FIG.1, the current sensors 28a, 28b measure A- phase current ia, and B-phase current ib on corresponding ones of the motor leads 24. However, the system 10 may measure current on any two of the motor leads 24. The system 10 may include other sensors, such as voltage sensors configured to measure voltages upon or between the motor leads 24. If voltage sensors are available, they can be used as inputs for the provided approach. The system 10 of FIG. 1 also includes an electronic control unit (ECU) 30, which may also be called a governing controller, in communication with the current sensor 28 to measure the currents in the motor leads 24. The ECU 30 may also be in functional communication with the inverter 20 to control operation of the inverter 20 and / or to monitor parameters measured by sensors associated with the inverter 20. The ECU 30 includes a processor 32 coupled to a storage memory 34. The storage memory 34 stores instructions, such as program code for execution by the processor 32, in an instruction storage 36. The storage memory 34 also includes data storage 38 for holding data to be used by the processor 32. The data storage 38 may record, for example, values of the parameters measured by the current sensor 28 and / or the outcome of functions calculated by the processor 32. A speed / position sensor 42 may measure a rotational position θ of the electric motor 26 that corresponds to an electrical rotational position θe. Alternatively or additionally, the speed / position sensor 42 may measure a rotational speed ω of the electric motor 26 that corresponds to an electrical rotational speed ωe of the electric motor 26. In some embodiments, the Attorney Docket No.18402-05176 (713271PCT) speed / position sensor 42 may include an encoder or a resolver connected to a shaft 40 of the electric motor 26. The speed / position sensor 42 may communicate the rotational position θ and / or the rotational speed ω of the electric motor 26 to the ECU 30. FIG. 2 shows a schematic diagram of a multilevel power converter 100 in accordance with the present disclosure. The multilevel power converter 100 may perform the functions of the inverter 20 and the DC power supply 23 in the system 10 for operating an EV. The multilevel power converter 100 includes three single-phase supplies 110a, 110b, 110c including a first single-phase supply 110a, also labeled Phase A, a second single-phase supply 110b, also labeled Phase B, and a third single-phase supply 110c, also labeled Phase C. Each of the phase supplies 110a, 110b, 110c includes several submodules 112a, 112b, 112c. The particular multilevel power converter 100 shown in FIG. 2 is merely an example, and the principles of the present disclosure may be applied to power converters have other configurations or designs. As shown in FIG.2, the multilevel power converter 100 is configured as a modular multilevel converter (MMC) that includes an AC bus 102a, 102b, 102c configured to transmit the AC power from the submodules 112a, 112b, 112c to the electric motor 26 via a bus connector 104 and via the motor leads 24. As also shown, the electric motor 26 is configured as a traction motor for accelerating a vehicle. The multilevel power converter 100 also includes the governing controller 30 that is in functional communication with each of the submodules 112a, 112b, 112c. Each of the submodules 112a, 112b, 112c includes a power converter 122 having a plurality of switching transistors, and connected to at least one battery 120. In some embodiments, each of the submodules 100a may be connected to a dedicated battery 120. Alternatively or additionally, some or all of the submodules 100a may be connected to a same battery 120. For Attorney Docket No.18402-05176 (713271PCT) example, as shown on FIG. 2, one of submodules 112a, 112b, 112c in each of the single-phase supplies 110a, 110b, 110c is connected to a same one of the batteries 120. The submodules 112a, 112b, 112c are configured in a multi-level series configuration within each of the single-phase supplies 110a, 110b, 110c to supply power on a corresponding conductor of the AC bus 102a, 102b, 102c at any one of a plurality of different voltage levels, depending on which and how many of the submodules 112a, 112b, 112c are active to supply power on the AC bus 102a, 102b, 102c at any given time. Additionally, the submodules 112a, 112b, 112c may include additional hardware and / or software for a battery management system (BMS) and / or a DC-DC converter to supply low voltage auxiliary loads using DC power from the batteries 120. Each of the submodules 112a, 112b, 112c also includes a module controller 124, which may also be called a SM controller, configured to control the switching transistors of the corresponding power converter 122 to operate the power converter 122 in one of a charging mode or an inverter mode. In the charging mode, the power converter 122 operates to rectify the AC power from the AC bus 102a, 102b, 102c and to supply direct current (DC) power to the battery 120 connected thereto. For example, the power converter 122 may be operated as a as a synchronous rectifier to convert the AC power to the DC power. The module controller 124 may function as a battery control module, regulating the amount of charging current based on one or more factors, such as state of charge, state of health, temperature, etc. In some embodiments, the governing controller 30 may control a distribution of charging and / or discharging current between the submodules 112a, 112b, 112c. For example, the governing controller 30 may identify a given one of the submodules 112a, 112b, 112c as having a battery 120 that is relatively weak, e.g. with a relatively low state of charge and / or state of health. Attorney Docket No.18402-05176 (713271PCT) The governing controller may call for that given one of the submodules 112a, 112b, 112c with the relatively weak battery to provide less output current than other ones of the submodules 112a, 112b, 112c during operation of the electric motor 26 for accelerating the vehicle. In the inverter mode the power converter 122 may operate to generate AC power on the AC bus using the DC power from the battery 120 connected thereto. For example, the module controller 124 may command the switching transistors of the corresponding power converter 122 to generate AC power having given characteristics, such as current, frequency, etc. based on one or more signals from the governing controller 30. In some embodiments, and as shown on FIG. 2, the each of the power converters 122 is configured as a full-bridge converter to provide inverter and on-board charger capabilities for charging the battery 120. However, the principles of the present disclosure are not limited to use with a full-bridge architecture. The module controller 124 for each of the submodules 112a, 112b, 112c are controlled by a governing controller 30 board that includes motor control and pack-level balancing of the SMs based on state-of-charge (SoC) and temperature. Conventional multilevel converters may use a wired connection is required with a given communication protocol to provide communication between the governing controller 30 and the plurality of module controller 124 in the submodules 112a, 112b, 112c. The system of the present disclosure replaces the wired connection between the governing controller and the SM PCBs with a wireless architecture. FIG. 3 depicts a conventional communications architecture and FIG. 4 depicts a proposed wireless architecture for a modular multilevel converter architecture. The system is comprised of several nodes that is equal to the number of submodules in the MMC architecture using any wireless communication protocol. The Attorney Docket No.18402-05176 (713271PCT) wireless communication protocol could operate with a data transmission rate that is optimized for the functionality that needs to be handled by the governing microcontroller. FIG. 3 shows a schematic block diagram illustrating a multilevel power converter 150 with several controllers 30, 124 with communications wiring 152 extending therebetween to provide data interconnections for communicating signals between the governing controller 30 and each of the module controllers 124. FIG. 4 shows a schematic block diagram illustrating a multilevel power converter 160 with several controllers 30, 124 having wireless data interconnections. In some embodiments, and as shown in FIG. 4, each of the module controllers 124 and the governing controller 30 includes a wireless communications interface 162, such as a transceiver that is configured to transmit and receive data. Each of the module controllers 124 may be configured to communicate with the with the governing controller 30 using a wireless data interconnection 164, which may also be called a wireless communications connection, between the corresponding wireless communications interfaces 162. In some embodiments, the governing controller is configured to command, via the wireless data interconnection, each of the module controllers to cause a corresponding one of the power converters to operate in a given one of the charging mode or the inverter mode. In some embodiments, the governing controller is configured to command, via the wireless data interconnection, an operating parameter for adjusting the operation of the corresponding one of the power converters while operating in the given one of the charging mode or the inverter mode. Attorney Docket No.18402-05176 (713271PCT) In some embodiments, the wireless transceiver includes a radio. In some embodiments, the wireless data interconnection includes at least one of Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), Zigbee, Matter, or Thread. In some embodiments, the wireless transceiver includes a light-based communications interface. In some embodiments, the module controllers are each configured for bidirectional communication with the governing controller using the wireless data interconnection. In some embodiments, the module controllers are each configured to communicate with at least one other one of the module controllers. In some embodiments, the module controllers are each configured to implement peer-to-peer communications for communicating with the governing controller. The system, methods and / or processes described above, and steps thereof, may be realized in hardware, software or any combination of hardware and software suitable for a particular application. The hardware may include a general purpose computer and / or dedicated computing device or specific computing device or particular aspect or component of a specific computing device. The processes may be realized in one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors or other programmable device, along with internal and / or external memory. The processes may also, or alternatively, be embodied in an application specific integrated circuit, a programmable gate array, programmable array logic, or any other device or combination of devices that may be configured to process electronic signals. It will further be appreciated that one or more of the processes may be realized as a computer executable code capable of being executed on a machine readable medium. Attorney Docket No.18402-05176 (713271PCT) The computer executable code may be created using a structured programming language such as C, an object oriented programming language such as C++, or any other high- level or low-level programming language (including assembly languages, hardware description languages, and database programming languages and technologies) that may be stored, compiled or interpreted to run on one of the above devices as well as heterogeneous combinations of processors processor architectures, or combinations of different hardware and software, or any other machine capable of executing program instructions. Thus, in one aspect, each method described above and combinations thereof may be embodied in computer executable code that, when executing on one or more computing devices performs the steps thereof. In another aspect, the methods may be embodied in systems that perform the steps thereof, and may be distributed across devices in a number of ways, or all of the functionality may be integrated into a dedicated, standalone device or other hardware. In another aspect, the means for performing the steps associated with the processes described above may include any of the hardware and / or software described above. All such permutations and combinations are intended to fall within the scope of the present disclosure. The foregoing description is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

Attorney Docket No.18402-05176 (713271PCT) CLAIMS What is claimed is:

1. A multilevel converter for generating alternating current (AC) power, comprising: an AC bus configured to transmit the AC power; a governing controller; and a plurality of submodules each including: a power converter having a plurality of switching transistors, and a module controller configured to control the plurality of switching transistors to operate in one of a charging mode or an inverter mode, wherein the power converter, in the charging mode, operates to rectify the AC power from the AC bus to supply direct current (DC) power to at least one battery, and wherein the power converter, in the inverter mode, operates to generate AC power on the AC bus using the DC power from the at least one battery, and wherein each of the module controllers includes a wireless transceiver configured to communicate with the governing controller using a wireless data interconnection.

2. The multilevel converter of Claim 1, wherein the governing controller is configured to command, via the wireless data interconnection, each of the module controllers to cause a corresponding one of the power converters to operate in a given one of the charging mode or the inverter mode.

3. The multilevel converter of Claim 2, wherein the governing controller is configured to command, via the wireless data interconnection, an operating parameter for adjusting theAttorney Docket No.18402-05176 (713271PCT) operation of the corresponding one of the power converters while operating in the given one of the charging mode or the inverter mode.

4. The multilevel converter of Claim 1, wherein the wireless transceiver includes a radio.

5. The multilevel converter of Claim 4, wherein the wireless data interconnection includes at least one of Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), Zigbee, Matter, or Thread.

6. The multilevel converter of Claim 1, wherein the wireless transceiver includes a light-based communications interface.

7. The multilevel converter of Claim 1, wherein the module controllers are each configured for bidirectional communication with the governing controller using the wireless data interconnection.

8. The multilevel converter of Claim 1, wherein the module controllers are each configured to communicate with at least one other one of the module controllers.

9. The multilevel converter of Claim 1, wherein the module controllers are each configured to implement peer-to-peer communications for communicating with the governing controller.Attorney Docket No.18402-05176 (713271PCT) 10. An electrified vehicle (EV) comprising: a traction motor configured to propel the EV; a multilevel converter for generating alternating current (AC) power, the multilevel converter including: an AC bus configured to transmit the AC power to the traction motor; a governing controller; and a plurality of submodules each including: a power converter having a plurality of switching transistors, and a module controller configured to control the plurality of switching transistors to operate in one of a charging mode or an inverter mode, wherein the power converter, in the charging mode, operates to rectify the AC power from the AC bus to supply direct current (DC) power to at least one battery, wherein the power converter, in the inverter mode, operates to generate AC power on the AC bus using the DC power from the at least one battery, and wherein each of the module controllers includes a wireless transceiver configured to communicate with the governing controller using a wireless data interconnection.

11. The electrified vehicle of Claim 10, wherein the governing controller is configured to command, via the wireless data interconnection, each of the module controllers to cause a corresponding one of the power converters to operate in a given one of the charging mode or the inverter mode.Attorney Docket No.18402-05176 (713271PCT) 12. The electrified vehicle of Claim 11, wherein the governing controller is configured to command, via the wireless data interconnection, an operating parameter for adjusting the operation of the corresponding one of the power converters while operating in the given one of the charging mode or the inverter mode.

13. The electrified vehicle of Claim 10, wherein the wireless transceiver includes a radio.

14. The electrified vehicle of Claim 10, wherein the wireless transceiver includes a light-based communications interface.

15. The electrified vehicle of Claim 10, wherein the module controllers are each configured for bidirectional communication with the governing controller using the wireless data interconnection.

Images