Modular multi-level power electronics and control architecture to supply multiple motors and auxiliary loads

Abstract

An integrated motor drive system includes a modular multi-level inverter having a plurality of integrated power modules each including; one or more battery cells connected to an internal DC bus, and a power converter assembly connected to the internal DC bus and configured to generate AC power using DC power from the one or more battery cells and to supply the AC power via a set of load terminals. Each of the integrated power modules also includes an isolated DC-DC power converter configured to provide isolated DC power to a DC output bus using DC input power from the internal DC bus. The integrated power modules are split between a plurality of phase groups with their load terminals connected in series between a lower node and an AC output conductor arranged to supply the AC power to a motor.

Description

Attorney Docket No. 18402-5390 (713884PCT)MODULAR MULTI-LEVEL POWER ELECTRONICS AND CONTROL ARCHITECTURE TO SUPPLY MULTIPLE MOTORS AND AUXILIARY LOADS CROSS REFERENCE TO RELATED APPLICATIONS[00011 This PCT international patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 779,774 filed March 28, 2025, the contents of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] In a conventional electric vehicle propulsion system, battery cells are packaged together in series and parallel configuration to develop a battery module, and a number of battery modules together create a complete battery pack. The battery pack is the main energy source connected to the motor and its drive system through a single DC link. Recently, modular multilevel inverters (MMI) have been developed to provide integrated configuration, scalability, compact and efficient design. In this configuration, battery cells or modules are connected to each other through power electronics circuit, such as full bridges and half bridges, which produce AC voltage to operate an electric motor (eMotor), such as a traction motor in an electrified vehicle. However, one of the main challenges with this configuration is to simultaneously supply power to a secondary traction drive, a heating, ventilation, and air conditioning (HVAC) system and other auxiliary loads. Additionally, the implementation of modulation strategy presents significant challenges with the increased number of levels, particularly when using conventional microcontroller units (MCUs). MMI requires a large number of PWM signals to control multiple switching devices. Conventional MCUs often lack the necessary number of PWM channels and the processing power to generate these signals with the required precision and timing. In addition, ensuring precise synchronization and timing of PWM signals is crucial for the proper operation of multi-level inverters. Conventional MCUs may face difficulties in maintaining the required timing accuracy, leading to suboptimal performance.SUMMARY

[0003] The present disclosure provides an integrated motor drive system that includes a modular multi-level inverter having a plurality of integrated power modules. Each of the integrated power modules includes: one or more battery cells connected to an internal DC bus, and a power converter assembly connected to the internal DC bus. The power converter assembly is configuredAttorney Docket No. 18402-5390 (713884PCT)to generate AC power using DC power from the one or more battery cells and to supply the AC power via a set of load terminals. Each of the integrated power modules further includes an isolated DC-DC power converter configured to provide isolated DC power to a DC output bus using DC input power from the internal DC bus. The plurality of integrated power modules are split between a plurality of phase groups, with each of the phase groups including a corresponding subset of the plurality of integrated power modules with the load terminals connected in series between a lower node and an AC output conductor. The AC output conductors of the plurality of phase groups together are arranged to supply the AC power to a motor.[0004| The present disclosure also provides a multi-level inverter system. The multi-level inverter system comprises a plurality of integrated power modules and an electronic controller. Each of the integrated power modules includes: one or more battery cells connected to an internal DC bus, and a power converter assembly connected to the internal DC bus and configured to generate AC power using DC power from the one or more battery cells and to supply the AC power via a first load terminal and a second load terminal. The electronic controller has a pulse width modulation output transmitting a shared pulse width modulation signal, wherein the controller further includes a plurality of digital outputs each transmitting a mode-control signal for a power converter assembly of the plurality of integrated power modules. At least two integrated power modules of the plurality of integrated power modules are arranged with their respective load terminals connected in series between a lower node and an AC output conductor, thereby defining a phase group for delivering a single phase AC power to a load connected between the lower node and the AC output conductor. Each power converter assembly of the phase group is arranged to use the shared pulse width modulation signal for controlling a switching operation of the power converter assembly at different times. The different times are set forth in accordance with the mode-control signal.|0005] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims, and the accompanying figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Further details, features and advantages of designs of the invention result from the following description of embodiment examples in reference to the associated drawings.Attorney Docket No. 18402-5390 (713884PCT)

[0007] FIG. 1 shows a schematic block diagram of an electrical system in an electrified vehicle (EV), and in accordance with an aspect of the present disclosure

[0008] FIG. 2 shows a schematic diagram of a first integrated motor drive (IMD) system having a three-phase modular multi-level inverter (MMI), according to the present disclosure;

[0009] FIG. 3 shows a schematic block diagram of a second IMD system for supplying power to multiple motors and auxiliary loads, in accordance with an aspect of the present disclosure;[0010| FIG. 4 shows a schematic diagram of a power converter assembly 138 with four solid-state switches in an H-bridge configuration, in accordance with an aspect of the present disclosure;

[0011] FIG. 5 shows a schematic diagram of a phase group of the three-phase MMI of the present disclosure;

[0012] FIG. 6 shows a graph illustrating a single-phase output voltage with a level-shift PWM technique, in accordance with an aspect of the present disclosure;

[0013] FIG. 7 shows a graph illustrating an output voltage of each submodule in the phase group of FIG. 5 operated using the level-shift PWM technique, in accordance with an aspect of the present disclosure;

[0014] FIG. 8 shows a block diagram illustrating a third IMD system with an MMI having a distributed control architecture, in accordance with an aspect of the present disclosure;

[0015] FIG. 9 shows a graph illustrating a voltage waveform generated by an MMI using the level-shift PWM technique, in accordance with an aspect of the present disclosure; and

[0016] FIG. 10 shows a graph illustrating a current waveform generated by an MMI using the level-shift PWM technique, in accordance with an aspect of the present disclosure.DETAILED DESCRIPTION

[0017] Referring to the drawings, the present invention will be described in detail in view of following embodiments.

[0018] It is an objective of the present disclosure to provide a Modular Multi-Level Power Electronics Architecture with the Capability to Supply Multiple Motors and Auxiliary Loads. It is a further objective of the present disclosure to provide a control architecture for Modular MultiLevel Inverter system with minimum PWM requirement for feasibility of implementation.Attorney Docket No. 18402-5390 (713884PCT)[0019| FIG. 1 shows a block diagram of an electrical system 10 for operating an electrified vehicle (EV). The EV may be configured as a battery electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV) or another type of hybrid electric vehicle that uses battery electric in combination with another source of energy for propulsion. The electrical system 10 is provided in a vehicle 12 having four wheels 14. The electrical system 10 includes a first battery 16 configured to supply power to one or more auxiliary loads 18. The axillary loads may include, low-power functional elements in the vehicle 12, such as heating ventilation and air conditioning (HVAC) motors, lighting loads, such as headlights and taillights, power steering and power brake motors, seat heaters, electrical control units (ECUs), seat actuators, window actuators, etc. The first battery 16 may be configured as a low-voltage battery, which may have an operating voltage of, for example, 12-Volts, 24-Volts, 36-Volts, 42-Volts, or48-Volts.

[0020] The electrical system 10 also includes a traction power source 20 that is configured to supply electrical power to an inverter 22 via a DC bus 21 for driving one or more traction motors 26 for propelling the vehicle 12. The traction power source 20 includes a second electrical energy storage device 40, which may be configured as a high-capacity main battery. Additionally or alternatively, the second electrical energy storage device 40 may include one or more capacitors.

[0021] The traction power source 20 also includes a third electrical energy storage device 42, which may be configured as a high-performance boost battery that is capable of delivering relatively high output power for a short duration of time. In some embodiments, the third electrical energy storage device 42 includes a battery, which may have a different chemistry than the first battery 16 and / or the second electrical energy storage device 40. Alternatively or additionally, the third electrical energy storage device 42 may include one or more capacitors, which may include super capacitors. The second electrical energy storage device 40 and / or the third electrical energy storage device 42 may have a relatively higher voltage, such as 400 Volts Direct Current (VDC), 800 VDC, or some nominal voltage between 400 VDC and 800VDC. In some embodiments, the second electrical energy storage device 40 and / or the third electrical energy storage device 42 may have a different voltage that is less than 400 VDC, such as 360VDC. Alternatively or additionally, the second electrical energy storage device 40 and / or the third electrical energy storage device 42 may have nominal voltage greater than 800 VDC.

[0022] The inverter 22 may include at least three pairs of solid-state switches 23, such as field effect transistors (FETs) configured to switch current from the DC bus 21 and to generate anAttorney Docket No. 18402-5390 (713884PCT)AC power upon a set of motor leads 24. The motor leads 24 transmit electrical power between the inverter 22 and a traction motor 26. The traction motor 26 may be a permanent magnet synchronous motor (PMSM). The traction 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 traction motor 26 may include an output shaft 27 that is coupled, either directly or via a transmission or gearbox (not shown in the FIGs), to one or more of the wheels 14 of the vehicle 12 for driving the vehicle 12.

[0023] A current sensor 28 is arranged to measure current in one or more of the motor leads 24. In some embodiments, and as shown on FIG. 1, the current sensor 28 measures an A-phase current ia, on a corresponding one of the motor leads 24. However, the electrical system 10 may measure current on two or more of the motor leads 24. The electrical 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.

[0024] The electrical 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 22 to control operation of the inverter 22 and / or to monitor parameters measured by sensors associated with the inverter 22. 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.[0025| FIG. 2 shows a first integrated motor drive (IMD) system 100 with a first modular multi-level inverter (MMI) configured for providing power to an electric motor 120 having a three-phase arrangement with windings La, Lb, Lc arranged in a Wye configuration. However, the electric motor 120 may have another configuration, such as a delta configuration. The electric motor 120 may be used as the traction motor 26 for generating a torque used to accelerate the vehicle 12. Alternatively, the electric motor 120 may be used for other purposes.

[0026] The first MMI 130 shown on FIG. 2 is configured to supply the electric motor 120 120 with three-phase power via a first terminal box 124, which may also be called an AC bus connector. The first MMI 130 includes three phase groups 132A, 132B, 132C, each generating aAttorney Docket No. 18402-5390 (713884PCT)single-phase of AC power for application to a corresponding stator winding of the electric motor 120. The three phase groups include an A-phase group 132A, a B-phase group 132B, and a C-phase group 132C. Each of the phase groups 132A, 132B, 132C includes several first integrated power modules 134 in a series configuration. Each of the first integrated power modules 134 may have a similar or identical configuration.

[0027] In some embodiments, and as shown on FIG. 2, each of the first integrated power modules 134 may be configured as primary modules, including a battery module 136. The battery module 136 may have a 12-V nominal voltage. However, the battery module 136 may have a different voltage, such as 24V, 36V, 48V, or 90V. Additionally or alternatively, some of the first integrated power modules 134 may be configured as secondary modules, which do not contain a battery, but instead are connected to an external battery.

[0028] Each of the first integrated power modules 134 includes an input capacitor 137, and a power converter assembly 138. The power converter assembly 138 may be physically and electrically coupled to the battery module 136 and configured to receive direct current (DC) power therefrom and to generate alternating current (AC) power on a set of load terminals 139, using the DC power from the battery module 136. In some embodiments, each of the power converter assemblies 138 may include four solid-state switches in an H-bridge configuration. The solid-state switches may include metal-oxide field effect transistor (MOSFET) devices, as shown on FIG. 2. However, other types of devices may be used, such as other types of field-effect transistors (FETs) or junction devices, such as insulated gate bipolar transistors (IGBT), silicon controlled rectifiers (SCRs), or thyristor devices. In some embodiments, one or more of the solid-state switches may include a Gallium Nitride (GaN) transistor, a Silicon Carbide (SiC) transistor, or another type of high electron mobility transistor (HEMT).

[0029] The load terminals 139 of the first integrated power modules 134 within each of the phase groups 132A, 132B, 132C are connected together in the series configuration to generate AC output power on a corresponding one of an A-phase AC output conductor 126 A, a B-phase AC output conductor 126B, or a C-phase AC output conductor 126C. Each of the phase groups 132A, 132B, 132C also defines a corresponding one of an A-phase lower node 128A, a B-phase lower node 128B, or a C-phase lower node 128C, opposite of the AC output conductors 126A, 126B, 126C. In other words, the load terminals 139 of the first integrated power modules 134 within each of the phase groups 132A, 132B, 132C are connected in series between one of the lower nodesAttorney Docket No. 18402-5390 (713884PCT)128A, 128B, 128C and a corresponding one of the AC output conductors 126A, 126B, 126C. Thus, the phase groups 132A, 132B, 132C may provide the three-phase AC power. The series connection of the first integrated power modules 134 enables each of the phase groups 132A, 132B, 132C to provide the AC output power with power and / or voltage ratings many times greater than can be supplied by any one of the first integrated power modules 134, alone.

[0030] The first MMI 130 shown on FIG. 2 also includes a module neutral conductor 126n, which may serve as a reference conductor and / or as a current carrying conductor for a single-phase load connected to one of the AC output conductors 126 A, 126B, 126C.[00311 The first IMD system 100 also includes a first set of contacts 140 configured to selectively connect the B-phase AC output conductor 126B with the C-phase AC output conductor 126C. The C-phase lower node 128C is connected to the module neutral conductor 126n. The first IMD system 100 also includes a second set of contacts 142 configured to selectively connect the B-phase first lower node 128B to the module neutral conductor 126n. The sets of contacts 140, 142 may function to connect the b and c phase groups 132B, 132C in series for DC fast charging.

[0032] The first set of contacts 140 and the second set of contacts 142 may be selectively commanded by the ECU 180 to convert the three phase groups 132A, 132B, 132C to a series connection and which may be connected to a DC charging station for DC charging. This is one possible connection, but the contacts 140, 142 can be reconfigured to other locations to achieve the same effect of converting the three phase groups 132A, 132B, 132C to a series connection during DC charging. This methodology is applicable to any number of phase groups 132A, 132B, 132C; however, a higher number of contacts 140, 142 may be required for more than three of the phase groups 132A, 132B, 132C. For example, a six-phase system may require four contacts in total.

[0033] FIG. 3 shows a schematic block diagram of a second IMD 200 with a second MMI 230 configured for providing power to a first electric motor 220, a second electric motor 222, and to one or more auxiliary loads. The first electric motor 220 and / or the second electric motor 222 may be used as the traction motor 26 for generating a torque used to accelerate the vehicle 12. Alternatively, the either or both of the first electric motor 220 and / or the second electric motor 222 may be used for other purposes. The second MMI 230 may be operated to drive the first electric motor 220 and the second electric motor 222 to run simultaneously with different speeds and torque outputs, and which may be controlled independently.Attorney Docket No. 18402-5390 (713884PCT)

[0034] The second MM I 230 includes several second integrated power modules 234 that each include: or more battery cells 236 connected to an internal DC bus 237, and a first power converter assembly 238 connected to the internal DC bus 237. The first power converter assemblies 238 are each configured to generate AC power using DC power from the one or more battery cells 236 connected thereto and to supply the AC power via a set of first load terminals 239. Each of the first power converter assemblies 238 may be called a full-bridge converter and may be similar or identical to the power converter assemblies 138 described above.

[0035] The first power converter assemblies 238 of the second MMI 230 are divided amongst three first phase groups 232a, 232b, 232c, each generating a single-phase of AC power for application to a corresponding stator winding of the first electric motor 220. Each of the first phase groups 232a, 232b, 232c includes several of the first power converter assemblies 238 with their respective first load terminals 239 in a series configuration to generate AC output power on a corresponding first AC output conductor 226a, 226b, 226c. Each of the first phase groups 232a, 232b, 232c also defines a corresponding first lower node 228a, 228b, 228c, opposite of the first AC output conductors 226a, 226b, 226c. As shown, the first lower nodes 228a, 228b, 228c are connected together to define a wye arrangement of the three first phase groups 232a, 232b, 232c. However, the first phase groups 232a, 232b, 232c may have a different wiring arrangement or an arrangement that is changeable using one or more sets of contacts, such as the contacts 140, 142 in the first MMI 130.[0036J Each of the second integrated power modules 234 also includes an isolated DC-DC power converter 240 and a second power converter assembly 244. The isolated DC-DC power converter 240 is configured to provide isolated DC power to a DC output bus 242 using DC input power from the internal DC bus 237. The second power converter assemblies 244 are each configured to generate a second AC power using the isolated DC power from the DC output bus 242 and to supply the second AC power via a set of second load terminals 245. Each of the second power converter assemblies 244 may be called a full-bridge converter and may be similar or identical to the power converter assemblies 138 described above.[0O37| The second power converter assemblies 244 of the second MMI 230 are divided amongst three second phase groups 233a, 233b, 233c, each generating a single-phase of AC power for application to a corresponding stator winding of the second electric motor 222. Each of the second phase groups 233 a, 233b, 233 c includes several of the second power converter assembliesAttorney Docket No. 18402-5390 (713884PCT)244 with their respective second load terminals 245 in a series configuration to generate AC output power on a corresponding second AC output conductor 246a, 246b, 246c. Each of the second phase groups 233a, 233b, 233c also defines a corresponding second lower node 248a, 248b, 248c, opposite of the second AC output conductors 246a, 246b, 246c. As shown, the second lower nodes 248a, 248b, 248c are connected together to define a wye arrangement of the second phase groups 233a, 233b, 233c. However, the second phase groups 233a, 233b, 233c may have a different wiring arrangement or an arrangement that is changeable using one or more sets of contacts, such as the contacts 140, 142 in the first MMI 130.[0038| At least one of the isolated DC-DC power converters 240 associated with each of the three first phase groups 232a, 232b, 232c is configured to provide a second isolated DC power to second DC output bus 250 using DC input power from its corresponding internal DC bus 237. The second DC output bus 250 may operate at a relatively high voltage, such as 360 VDC or 400 VDC. The second DC output buses 250 are arranged to supply DC power to a first auxiliary load 252, such as one or more heating, ventilation, and air conditioning (HVAC) devices. The first auxiliary load 252 may include, for example, a refrigerant compressor, a coolant circulation pump, and / or a blower motor. FIG. 3 shows one of the isolated DC-DC power converters 240 associated with each of the three first phase groups 232a, 232b, 232c with their respective second DC output buses 250 each connected in parallel to supply the first auxiliary load 252. However, the second DC output buses 250 of any number of the isolated DC-DC power converters 240 in the second MMI 230 may be connected together to supply power to the first auxiliary load 252. Furthermore, the second DC output buses 250 of the isolated DC-DC power converters 240 may be connected in a different configuration, such as a series arrangement or a series / parallel arrangement. The arrangement may depend on particular system requirements and / or capabilities of the isolated DC-DC power converters 240.|0039] At least one of the isolated DC-DC power converters 240 associated with each of the three first phase groups 232a, 232b, 232c is also configured to provide a third isolated DC power to third DC output bus 260 using DC input power from its corresponding internal DC bus 237. The third DC output bus 260 may operate at a relatively low voltage, such as 12 VDC or 48 VDC. The third DC output buses 260 are arranged to supply DC power to a second auxiliary load 262, such as one or more electronic control units, actuator motors, heaters, etc. FIG. 3 shows one of the isolated DC-DC power converters 240 associated with each of the three first phase groupsAttorney Docket No. 18402-5390 (713884PCT)232a, 232b, 232c with their respective third DC output buses 260 each connected in parallel to supply the second auxiliary load 262. However, the third DC output buses 260 of any number of the isolated DC-DC power converters 240 in the second MMI 230 may be connected together to supply power to one or more of the second auxiliary loads 262. Furthermore, the third DC output buses 260 of the isolated DC-DC power converters 240 may be connected in a different configuration, such as a series arrangement or a series / parallel arrangement. The arrangement may depend on particular system requirements and / or capabilities of the isolated DC-DC power converters 240.[0040| The present disclosure provides a modular multi-level power electronics architecture with the capability to supply multiple motors and auxiliary loads, as shown in FIG. 3. The modular multi-level power electronics architecture may provide a modular multi-level power converter, which may also be called a modular multi-level inverter (MMI).[0041 The modular multi-level power electronics system of the present disclosure comprises a plurality of integrated power modules. Each of the integrated power modules includes one or more battery cells, two full bridge inverters, and an isolated DC-DC converter. Each of the isolated DC-DC converters may also be called a DC / DC converter and may convert DC input power to generate an isolated DC output power, which may have a different voltage than the DC input power. The assembly is configured to generate AC power for both primary and secondary motors from the same battery source. Each submodule generates AC power for the primary motor using an H-bridge directly connected to the battery and AC power for the secondary motor, is generated by an H-bridge connected to an isolated DC-DC converter, which is also linked to the battery source. Types of isolated DC-DC converters include, but are not limited to: flyback, forward, half-bridge, full-bridge, Cuk, and inductor-inductor-capacitor (LLC) converters. The isolated DC-DC converter of each submodule can be designed with a single output or multiple outputs. With multi-output design, the system will have the capability to power HVAC and auxiliary load. FIG. 3 shows an example of an isolated DC / DC converter connected to the last battery of the integrated power modules in each of the phase groups. The outputs of the isolated DC / DC converters from each phase can be interconnected either in series or in parallel, depending on the power requirements, to provide a stable and reliable power supply for HVAC systems and auxiliary loads. This modular multi-level power electronics architecture is verified in a SimulinkAttorney Docket No. 18402-5390 (713884PCT)simulation environment. Both primary motor and secondary motor may run simultaneously with different speed and torque. The power provided to HVAC and auxiliary load is also stable.

[0042] The benefits of this architecture are multifaceted and offer significant advantages for modern e-drive systems. Firstly, it allows for a single printed circuit board (PCB) circuit to control both the primary and secondary motors, which simplifies the design and reduces the overall system complexity. This integration minimizes the number of components required, leading to lower manufacturing costs and a more compact system layout. Secondly, by eliminating the need for a high voltage bus in the e-drive system, the architecture enhances safety and reduces potential points of failure. This also simplifies the insulation requirements and reduces the risk of high voltage arcing and related failures. Additionally, multi-level architecture contributes to high efficiency for both the primary and secondary motors. This integrated approach not only streamlines the power electronics system but also enhances reliability and efficiency, making it a robust solution for modern dual e-drive applications. Additionally, the use of isolated DC-DC converters with single or multiple outputs adds another layer of versatility. With multi-output designs, the system can power not only the primary and secondary motors but also auxiliary loads such as HVAC systems and other onboard electronics. This capability ensures that all electrical needs of the vehicle or machine are met efficiently from a single integrated power source. Additional advantages of the systems and methods of the present disclosure include capabilities to provide load balancing between battery cells and to prevent or minimize asynchronous depletion of the battery cells.Modular Multi-Level Power Electronics Control Architecture[0043| The present disclosure also provides a matrix pulse-width modulation (PWM) modulation strategy for the multi-level inverter system control. For the MMI system, each fullbridge needs 4 PWM signals as shown in FIG. 4; therefore, the supervisory controller needs (4 * N, N is the number of submodules) PWM channels to run the one motor apart from other operations, such as the DC-DC converter, etc. If the supervisory controller doesn’t have enough PWM channels, then multiple supervisory controllers with enough PWM channels may need to be operated in synchronism. In case of any synchronization delay between the supervisory controllers, the output voltage of each submodule can be out of synchronization. This could result in injectionAttorney Docket No. 18402-5390 (713884PCT)of torque / stator current ripples due to higher THD on the resultant AC voltage produced by the MM I system.

[0044] FIG. 4 shows a schematic diagram of a power converter assembly 138, which may be called a full-bridge inverter and which includes a DC positive terminal 150P and a DC negative terminal 150N for connection to a DC source, such as the battery module 136. The power converter assembly 138 also includes a first load terminal 160 and a second load terminal 162 that together comprise the load terminals 139.

[0045] The power converter assembly 138 includes four solid-state switches 154H, 154L, 158H, 158L in an H-bridge configuration forming a first leg 152 and a second leg 156 that are each connected between the DC positive terminal 150P and the DC negative terminal 150N. The first leg 152 is configured to selectively conduct current between the first load terminal 160 and one of the DC positive terminal 150P or the DC negative terminal 150N at any given time. Similarly, the second leg 156 is configured to selectively conduct current between the second load terminal 162 and one of the DC positive terminal 150P or the DC negative terminal 150N at any given time.

[0046] The first leg 152 includes a first high-side switch 152H arranged to selectively conduct current between the DC positive terminal 150P and the first load terminal 160. The first leg 152 also includes a first low-side switch 154L arranged to selectively conduct current between the DC negative terminal 150N and the first load terminal 160. The first high-side switch 152H and the first low-side switch 154L may be controlled by gate drive signals with complementary states (labeled g_l and g_l', respectively) to prevent short circuit current from being conducted directly through the first leg 152 between the DC positive terminal 150P and the DC negative terminal 150N.

[0047] The second leg 156 includes: a second high-side switch 158H arranged to selectively conduct current between the DC positive terminal 150P and the second load terminal 160. The second leg 156 also includes a second low-side switch 158L arranged to selectively conduct current between the DC negative terminal 150N and the second load terminal 162. The second high-side switch 158H and the second low-side switch 158L may be controlled by gate drive signals with complementary states (labeled g_2' and g_2, respectively) to prevent short circuit current from being conducted directly through the second leg 156 between the DC positive terminal 150P and the DC negative terminal 150N.Attorney Docket No. 18402-5390 (713884PCT)

[0048] Additional deadtime considerations may be included for generating each of the gate drive signals g_l, g_l ', g_2, g_2'. Conventional motor drive controller arrangements may require four PWM outputs to control the four gate drive signals g_l, g_T, g_2, g_2' of each power converter assembly 138.[0049| FIG. 5 shows a schematic diagram of the A-phase group 132A of the first MMI 130. As shown, the A-phase group 132A includes four of the first integrated power modules 134 with their respective load terminals 160, 162 in a series configuration between the A-phase AC output conductor 126A. The four first integrated power modules 134 are labeled 134A, 134B, 134C, and 134D.

[0050] The A-phase group 132A includes an uppermost integrated power module 134A, with its first load terminal 160 connected directly to the A-phase AC output conductor 126A. The uppermost integrated power module 134A includes a first leg 152 and a second leg 156 that are labeled Al and A2, respectively. The A-phase group 132A also includes a second-tier integrated power module 134B, with its first load terminal 160 connected directly to the second load terminal 162 of the uppermost integrated power module 134A. The second-tier integrated power module 134B includes a first leg 152 and a second leg 156 that are labeled Bl and B2, respectively. The A-phase group 132A also includes a third-tier integrated power module 134C, with its first load terminal 160 connected directly to the second load terminal 162 of the second-tier integrated power module 134B. The third-tier integrated power module 134C includes a first leg 152 and a second leg 156 that are labeled Cl and C2, respectively. The A-phase group 132A also includes a fourthtier integrated power module 134D with its first load terminal 160 connected directly to the second load terminal 162 of the third-tier integrated power module 134C. The fourth-tier integrated power module 134D includes a first leg 152 and a second leg 156 that are labeled DI andD2, respectively.

[0051] FIG. 6 shows a graph illustrating a single-phase output voltage with a level-shift PWM technique. The single-phase output voltage may represent an AC voltage generated by the A-phase group 132A, between the A-phase AC output conductor 126A and the A-phase lower node 128A. As shown, the single-phase output voltage includes four steps in each of a positive half-cycle, between times 0 - 5 ms, and four steps in a negative half-cycle, between times 5 - 10 ms.10052] Between times t = 0 and tl and also between times t6 and t7, the single-phase output voltage varies between 0 and 12v. During these periods of time, the first leg 152 of the fourthAttorney Docket No. 18402-5390 (713884PCT)integrated power module 134D (i.e. leg DI) may be controlled by a PWM signal. All of the other first integrated power modules 134A - 134C may be operated during these time periods in a bypass mode to conduct current directly between their respective load terminals 160, 162.

[0053] Between times tl and t2 and also between times t5 and t6, the single-phase output voltage varies between 12v and 24v. During these periods of time, the first leg 152 of the third-tier integrated power module 134C (i.e. leg Cl) may be controlled by the PWM signal, while the first leg 152 of the fourth integrated power module 134D (i.e. leg DI) is driven to a constant high state to conduct current between its DC positive terminal 150P and its first load terminal 160, thereby supplying a baseline 12V voltage. All of the other first integrated power modules 134A -134B may be operated during these time periods in a bypass mode to conduct current directly between their respective load terminals 160, 162.

[0054] Between times t2 and t3 and also between times t4 and t5, the single-phase output voltage varies between 24v and 36v. During these periods of time, the first leg 152 of the second-tier integrated power module 134B (i.e. leg Bl) may be controlled by the PWM signal, while the first legs 152 of each of the third-tier integrated power module 134C and the fourth-tier integrated power module 134D (i.e. legs Cl and DI) are each is driven to a constant high state to conduct current between their respective DC positive terminal 150P and their respective first load terminal 160, thereby supplying a baseline 24V voltage. The uppermost integrated power module 134A may be operated during these time periods in a bypass mode to conduct current directly between its respective load terminals 160, 162.

[0055] Between times t3 and t4 the single-phase output voltage varies between 36v and 48v. During this period of time, the first leg 152 of the uppermost integrated power module 134A (i.e. leg Al) may be controlled by the PWM signal, while the first legs 152 of each of each of the remaining first integrated power modules 134A - 134C (i.e. legs Bl, Cl and DI) are each is driven to a constant high state to conduct current between their respective DC positive terminal 150P and their respective first load terminal 160, thereby supplying a baseline 36V voltage.[0056| The second legs 154 of the four first integrated power modules 134A, 134B, 134C, and 134D can be similarly controlled using the same PWM signal to generate similar negative voltage steps during the negative half-cycle, between times t7 and 114 shown on FIG. 6. As shown on FIG. 6, the A-phase group 132A, with four of the first integrated power modules 134 connected in series, may be operated using level-shift PWM technique to provide nine different voltage stepAttorney Docket No. 18402-5390 (713884PCT)values. The voltages shown on FIG. 6 and described above, are merely an example and the levelshift PWM technique described may be used with different voltage values for each voltage step and / or a different number of the voltage steps. For example, the level-shift PWM technique may be used with a phase group having five of the first integrated power modules 134 connected in series to provide eleven different voltage step values.

[0057] It should be noted that each reference to one of the first legs 152 being controlled by the PWM signal may be understood to mean controlling operation of the first high-side switch 154H by the PWM signal while the second low-side switch 158L is maintained in a conductive state. A similar or identical result can also be obtained by controlling operation of the second low-side switch 158L by the PWM signal while the first high-side switch 154H is maintained in a conductive state. Likewise, each reference to one of the second legs 154 being controlled by the PWM signal may be understood to mean controlling operation of the second high-side switch 158H by the PWM signal while the first low-side switch 154L is maintained in a conductive state. A similar or identical result can also be obtained by controlling operation of the first low-side switch 154L by the PWM signal while the second high-side switch 158H is maintained in a conductive state.

[0058] As seen in FIG. 6, in a level-shift modulation-based MMI system, only one of the first leg 152 or the second leg 156 in one of the first integrated power module 134 of the entire A-phase group 132A is switching at any given point in time. During the other period, it is either operating always ON or OFF. This patterned operation will result in the single-phase voltage as seen in FIG. 7. Since only one leg of the full bridge switches at any given point in time, the proposed Matrix PWM uses only a single PWM channel and multiple GPIOs (general purpose input and output) to logically route the PWM channel using a logic mux circuit to different full bridge legs (such as Al, A2, Bl, B2, etc. in FIG. 5) in a calculated time sequence. Therefore, a single supervisory controller only needs 3 PWM and multiple GPIOs to control the three-phase e-motor system as seen in FIG. 8 for a number of N levels in the three-phase multilevel inverter.[0059| FIG. 7 shows a graph illustrating an output voltage of each submodule the phase group of FIG. 5 operated using the level-shift PWM technique. FIGs. 5-7 and the above description illustrate how a single PWM signal can be used to control several different first integrated power modules 134 in a phase group of a MMI, at different times. Thus, a single PWM output of a controller can be shared between multiple different first integrated power modules 134.Attomey Docket No. 18402-5390 (713884PCT)

[0060] FIG. 8 shows a block diagram illustrating a third IMD system 300 with a third MMI 330 configured for providing power to a third electric motor 330. The third electric motor 330 may be used as the traction motor 26 for generating a torque used to accelerate the vehicle 12. Alternatively, the third electric motor 330 may be used for other purposes.[00611 The third MMI 330 includes three phase groups 332A, 332B, 332C, each defining a corresponding one of three AC output conductors 326A, 326B, 326C. Each of the three phase groups 332A, 332B, 332C generates a single-phase of AC power for application to a corresponding stator winding of the third electric motor 330. The three phase groups include an A-phase group 332A, a B-phase group 332B, and a C-phase group 332C.[00621 Each of the phase groups 332A, 332B, 332C includes four third integrated power modules 334. However, the phase groups 332A, 332B, 332C may have a different number of the third integrated power modules 334. Each of the third integrated power modules 334 may be similar or identical to the first integrated power modules 134 described above. Each of the third integrated power modules 334 includes a third power converter assembly 338, and the third power converter assemblies 338 in each of the three phase groups 332A, 332B, 332C are connected in series to provide AC current to the third electric motor 330 via a corresponding one of three AC output conductors 326A, 326B, 326C. Each of the third power converter assemblies 338 may have a similar or identical configuration, which may be similar or identical to the power converter assembly 138 shown on FIG. 4 and described above.

[0063] The third IMD system 300 also includes an electronic controller 380, such as a microprocessor or microcontroller (pc) unit, that is configured to control operation of the third power converter assemblies 338 in each of the third integrated power modules 334. The electronic controller 380 has a plurality of digital output conductors, which may also be called general-purpose input / output (GPIOs), which include: two mode-control outputs providing two corresponding mode-control signals 352 for each of the third power converter assemblies 338. The plurality of digital outputs also includes three independent pulse width modulation (PWM) outputs each providing a corresponding one of three shared PWM signals 350A, 350B, 35OC for operation of the third power converter assemblies 338 in a corresponding phase group of the of the three phase groups 332A, 332B, 332C. The three shared PWM signals 350A, 35OB, 350C include an A-phase PWM signal 350A that is shared amongst all of the third integrated power modules 334 in the A-phase group 332A. The three shared PWM signals 350A, 350B, 350C also include a B-Attorney Docket No. 18402-5390 (713884PCT)phase PWM signal 350B that is shared amongst all of the third integrated power modules 334 in the B-phase group 332B. The three shared PWM signals 350A, 350B, 35OC also include a C-phase PWM signal 350C that is shared amongst all of the third integrated power modules 334 in the C-phase group 332C.[0064| The two corresponding mode-control signals 352 may, together define a plurality of different states to dictate operation of the four solid-state switches 154H, 154L, 158H, 158L therein. The plurality of different states may include at least one positive output state in which at least one of the first high-side switch 154H and / or the second low-side switch 158L is driven by the shared pulse width modulation signal to cause the third power converter assembly 338 to generate a positive voltage output between the first load terminal 160 and the second load terminal 162 and which varies in accordance with the shared pulse width modulation signal. The plurality of different states may also include at least one negative output state in which at least one of the first low-side switch 154L and / or the second high-side switch 158H is driven by the shared pulse width modulation signal to cause the third power converter assembly 338 to generate a negative voltage output between the first load terminal 160 and the second load terminal 162 and which varies in accordance with the shared pulse width modulation signal.

[0065] The plurality of different states may also include one or more constant positive voltage states in which the first high-side switch 154H and the second low-side switch 158L are each driven to a conductive condition to generate a positive voltage output between the first load terminal 160 and the second load terminal 162 and which is substantially equal to the DC voltage between the DC positive terminal 150P and the DC negative terminal 150N. The plurality of different states may also include one or more constant negative voltage states in which the first low-side switch 154L and the second high-side switch 158H are each driven to a conductive condition to generate a negative voltage output between the first load terminal 160 and the second load terminal 162 and which is substantially equal to the DC voltage between the DC positive terminal 150P and the DC negative terminal 150N.[0066| In some embodiments, the plurality of different states may also include one or more bypass states in which the four solid-state switches 154H, 154L, 158H, 158L are operated to conduct current directly between the first load terminal 160 and the second load terminal 162 without applying any voltage therebetween.Attorney Docket No. 18402-5390 (713884PCT)

[0067] As shown, each of the third integrated power modules 334 also includes a logic multiplexer 340 that is connected to one of the PWM outputs and two of the mode-control outputs of the electronic controller 380 for monitoring the two corresponding mode-control signals 352 and a corresponding one of three shared PWM signals 350A, 35OB, 350C. The logic multiplexer 340 is configured to selectively drive each of the solid-state switches the third power converter assembly 338 connected thereto using the two corresponding mode-control signals 352 and a corresponding one of three shared PWM signals 350A, 350B, 350C, thereby causing the corresponding phase group of the of the three phase groups 332A, 332B, 332C to generate the output voltage in accordance with the level-shift PWM technique describe above and illustrated on FIGs. 4-7.

[0068] FIG. 9 shows a graph illustrating a voltage waveform generated by an MMI using the level-shift PWM technique of the present disclosure, and FIG. 10 shows a graph illustrating a current waveform generated by an MMI using the level-shift PWM technique of the present disclosure.

[0069] The present disclosure provides an isolated DC-DC converter with single or multiple outputs connected with each battery module. With multi-output designs, the system can power not only the primary and secondary motors but also auxiliary loads such as HVAC systems and other onboard electronics from the same battery array. This capability ensures that all electrical needs of the vehicle or machine are met efficiently from a single integrated power source.

[0070] The present disclosure includes:1) Modular Multi-Level Power Electronics Architecture with the Capability to Supply Multiple Motors and Auxiliary Loads. This architecture allows for a single PCB circuit to control both the primary and secondary motors and supply power to HVAC and auxiliary loads, which simplifies the design and reduces the overall system complexity. Additionally, multi-level architecture is used to control both the primary and secondary motors with efficiency improvement.2) Modular Multi-Level Power Electronics Control Architecture - This control architecture adopts a matrix PWM modulation strategy, which achieve the minimum number of PWM generation for multi-level inverter (MMI) system (only 3PWM is required for a three-phase MMI regardless of number of levels)|0O71] 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 aAttorney Docket No. 18402-5390 (713884PCT)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 devices, 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.

[0072] 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, combinations of different hardware and software, or any other machine capable of executing program instructions.[00731 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 functionalities 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.

[0074] 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. 18402-5390 (713884PCT)CLAIMSWhat is claimed is:

1. An integrated motor drive system, comprising:a modular multi-level inverter including a plurality of integrated power modules, wherein each of the integrated power modules includes: one or more battery cells connected to an internal DC bus, and a power converter assembly connected to the internal DC bus and configured to generate AC power using DC power from the one or more battery cells and to supply the AC power via a set of load terminals,wherein each of the integrated power modules further includes an isolated DC-DC power converter configured to provide isolated DC power to a DC output bus using DC input power from the internal DC bus, andwherein the plurality of integrated power modules are split between a plurality of phase groups, with each of the phase groups including a corresponding subset of the plurality of integrated power modules with the load terminals connected in series between a lower node and an AC output conductor for supplying the AC power to a motor.

2. The integrated motor drive system of Claim 1 , wherein each of the integrated power modules further includes a second power converter assembly configured to generate a second AC power using the isolated DC power from the DC output bus and to supply the AC power via a second set of load terminals,wherein the second sets of load terminals in each phase group of the plurality of phase groups are connected in series between a second lower node and a second AC output conductor,Attorney Docket No. 18402-5390 (713884PCT)with the second AC output conductors of the plurality of phase groups together arranged to supply the second AC power to a second motor.

3. The integrated motor drive system of Claim 1 , wherein each of the power converter assemblies includes a full-bridge inverter having four solid-state switches in an H-bridge configuration.

4. The integrated motor drive system of Claim 1, wherein the isolated DC-DC power converter is further configured to provide a second isolated DC power to a second DC output bus using the DC input power from the internal DC bus.

5. The integrated motor drive system of Claim 4, wherein the second DC output busses of at least one of the isolated DC-DC power converter in each phase group of the plurality of phase groups are connected together to supply DC power to a first auxiliary load.

6. The integrated motor drive system of Claim 4, wherein the isolated DC-DC power converter is further configured to provide a third isolated DC power to a third DC output bus using the DC input power from the internal DC bus.

7. The integrated motor drive system of Claim 6, wherein the third DC output busses of at least one of the isolated DC-DC power converter in each phase group of the plurality of phase groups are connected together to supply DC power to a second auxiliary load.Attorney Docket No. 18402-5390 (713884PCT)8. The integrated motor drive system of Claim 1, further including an electronic controller configured to control operation of the power converter assemblies in each of the plurality of integrated power modules,wherein the electronic controller has a plurality of digital outputs including: two modecontrol outputs for each integrated power module of the plurality of integrated power modules, and a pulse width modulation output that is shared amongst the plurality of integrated power modules.

9. The integrated motor drive system of Claim 8, wherein the plurality of phase groups includes three of the phase groups, andwherein the pulse width modulation output of the electronic controller is one of three independent pulse width modulation outputs each controlling operation of the power converter assemblies in a corresponding phase group of the plurality of phase groups.

10. The integrated motor drive system of Claim 8, wherein each phase group includes four of the integrated power modules.

11. A multi-level inverter system, comprising:a plurality of integrated power modules, wherein each of the integrated power modules includes: one or more battery cells connected to an internal DC bus, and a power converter assembly connected to the internal DC bus and configured to generate AC power using DC powerAttorney Docket No. 18402-5390 (713884PCT)from the one or more battery cells and to supply the AC power via a first load terminal and a second load terminal; andan electronic controller having a pulse width modulation output transmitting a shared pulse width modulation signal, wherein the controller further includes a plurality of digital outputs each transmitting a mode-control signal for a power converter assembly of the plurality of integrated power modules,wherein at least two integrated power modules of the plurality of integrated power modules are arranged with their respective load terminals connected in series between a lower node and an AC output conductor, thereby defining a phase group for delivering a single phase AC power to a load connected between the lower node and the AC output conductor,wherein each power converter assembly of the phase group is arranged to use the shared pulse width modulation signal for controlling a switching operation of the power converter assembly at different times, and wherein the different times are set forth in accordance with the mode-control signal.

12. The multi-level inverter system of Claim 11, wherein the phase group is one of three phase groups that each include a corresponding subset of the plurality of integrated power modules, andwherein the pulse width modulation output of the electronic controller is one of three independent pulse width modulation outputs each associated with a corresponding phase group of the three phase groups,Attorney Docket No. 18402-5390 (713884PCT)wherein each of the three independent pulse width modulation outputs is shared amongst and used by the corresponding subsets of the plurality of integrated power modules for controlling the switching operation of the power converter assemblies therein.

13. The multi-level inverter system of Claim 11 , wherein the phase group includes four of the integrated power modules arranged with their respective load terminals connected in series between the lower node and the AC output conductor.

14. The multi-level inverter system of Claim 11, wherein each of the integrated power modules further includes a logic multiplexer connected to the pulse width modulation output and arranged to receive the mode-control signal for a power converter assembly of the plurality of integrated power modules;wherein each of the power converter assemblies includes a full-bridge inverter having four solid-state switches in an H-bridge configuration with a first leg and a second leg,wherein the first leg includes: a first high-side switch of the solid-state switches arranged to selectively conduct current between a DC positive terminal of the internal DC bus and the first load terminal, and a first low-side switch of the solid-state switches arranged to selectively conduct current between a DC negative terminal of the internal DC bus and the first load terminal, wherein the second leg includes: a second high-side switch of the solid-state switches arranged to selectively conduct current between the DC positive terminal of the internal DC bus and the second load terminal, and a second low-side switch of the solid-state switches arranged to selectively conduct current between the DC negative terminal of the internal DC bus and the second load terminal,Attorney Docket No. 18402-5390 (713884PCT)wherein the logic multiplexer is configured to drive the first leg and the second leg to one of a plurality of different states in response to the mode-control signal,wherein the plurality of different states include at least one positive output state in which at least one of the first high-side switch and / or the second low-side switch is driven by the shared pulse width modulation signal to cause the power converter assembly to generate a positive voltage output between the first load terminal and the second load terminal and which varies in accordance with the shared pulse width modulation signal, andwherein the plurality of different states include at least one negative output state in which at least one of the first low-side switch and / or the second high-side switch is driven by the shared pulse width modulation signal to cause the power converter assembly to generate a negative voltage output between the first load terminal and the second load terminal and which varies in accordance with the shared pulse width modulation signal.

15. The multi-level inverter system of Claim 11, wherein the phase group is one of a plurality of phase groups that each include a corresponding subset of the plurality of integrated power modules,wherein each of the integrated power modules further includes an isolated DC-DC power converter configured to provide isolated DC power to a DC output bus using DC input power from the internal DC bus,wherein each of the integrated power modules further includes a second power converter assembly configured to generate a second AC power using the isolated DC power from the DC output bus and to supply the AC power via a second set of load terminals, andAttorney Docket No. 18402-5390 (713884PCT)wherein the second sets of load terminals in each phase group of the plurality of phase groups are connected in series between a second lower node and a second AC output conductor, with the second AC output conductors of the plurality of phase groups together arranged to supply the second AC power to a second motor.

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