Power system for an electric drive system and method for controlling same

Abstract

The power system for the vehicle includes one or more power conversion systems electrically connected in parallel for each phase of the electric motor of the electric drive system. Each power conversion system is electrically coupled to a set of energy storage modules of the energy storage pack. Each power conversion system includes a power circuit and a power controller. The power circuits are electrically coupled to the respective set of energy storage modules and configured to provide a drive power output to the electric drive system and an auxiliary power output to the power bus. The power controller is configured to control the power circuits to provide the drive power output based on a desired power output of the electric drive system.

Description

[Technical field]

[0001] The present disclosure relates to power systems for electric drive systems for vehicles. [Background technology]

[0002] The statements in this section are merely intended to provide background information related to the present disclosure and may not constitute prior art.

[0003] Electric vehicles, which may include ground and air vehicles, are typically powered by an electric drive system having an electric motor and a power system that provides power to one or more buses for powering additional devices on the electric vehicle. Current architectures used for power systems may have several challenges. For example, current electric drive systems may require customization of the design for each model, slowing component development, and non-scalable power systems may limit opportunities for simple upgrades. Additionally, current architectures for power systems may use filtering units, which may lead to increased system size and weight. These and other issues with power systems are addressed by the present disclosure. Summary of the Invention

[0004] This section provides a general summary of the disclosure and is not an exhaustive disclosure of the entire scope or all features of the disclosure.

[0005] In one aspect, the disclosure is directed to a power system for a vehicle; the vehicle includes a power bus, an electric drive system, and an energy storage pack. The power system includes one or more power conversion systems electrically connected in parallel to each phase of an electric motor of the electric drive system. Each power conversion system is electrically coupled to a set of energy storage modules of a plurality of energy storage modules of the energy storage pack. Each power conversion system includes a power circuit and a power controller. The power circuit is electrically coupled to each set of energy storage modules and configured to provide a drive power output to the electric drive system and to provide an auxiliary power output to the power bus. The power controller is configured to control the power circuit to provide the drive power output based on a desired power output of the electric drive system.

[0006] The following include variations on the power system of the above paragraphs, which may be implemented individually or in any combination.

[0007] In some variations, the power circuit includes a three-level direct current to alternating current (DC-AC) inverter configured to provide the drive power output.

[0008] In some variations, the power circuitry includes a direct current to direct current (DC-DC) circuitry configured to provide an auxiliary power output to the power bus.

[0009] In some variations, the DC-DC converters of the power circuits of at least two of the one or more power conversion systems are electrically coupled in series to provide respective auxiliary power outputs to the power bus.

[0010] In some variations, the DC-DC converters of the power circuits of at least two of the one or more power conversion systems are electrically coupled in parallel to provide respective auxiliary power outputs to the power bus.

[0011] In some variations, the vehicle includes a plurality of power buses: DC-DC converters of power circuits of at least two of the one or more power conversion systems are electrically coupled to provide a respective auxiliary power output to a first power bus of the plurality of power buses; and a DC-DC converter of a power circuit of a third power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a second power bus of the plurality of power buses.

[0012] In some variations, the power circuit includes a three-level direct current-to-alternating current (DC-AC) inverter configured to provide a drive power output and a direct current-to-direct current (DC-DC) circuit configured to provide an auxiliary power output to the power bus, the DC-AC inverter and the DC-DC converter being electrically isolated from each other.

[0013] In some variations, the vehicle includes a plurality of power buses: a power circuit of a first power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a first power bus of the plurality of power buses; and a power circuit of a second power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a second power bus of the plurality of power buses.

[0014] In some variations, each power conversion system includes a plurality of power circuits and a plurality of power controllers forming a plurality of subsystem modules configured to provide a drive power output and an auxiliary power output, each subsystem module of the plurality of subsystem modules includes a power circuit of the plurality of power circuits electrically coupled to a subset of the energy storage modules selected from the set of energy storage modules, and a power controller of the plurality of power controllers configured to control the power circuit.

[0015] In some variations, a power controller of the power conversion system is configured to: obtain a desired power output based on operating conditions of the electric drive system; determine a state of charge of each energy storage module of the set of energy storage modules; and determine a power setpoint to be provided by the power conversion system based on the desired power output and the state of charge of the set of energy storage modules.

[0016] In some variations, the power controller is configured to determine the virtual resistance based on a state of charge of the set of energy storage modules, and the power set point is further determined based on the virtual resistance.

[0017] In some variations, the power controller is configured to determine an estimated state of charge of each energy storage module in response to the drive power output being applied to the electric drive system; and the subsequent power set point is determined based on the estimated state of charge.

[0018] In some variations, the system includes an electric drive system including an electric motor, and a power system in which one or more power conversion systems are provided for each phase of the electric motor.

[0019] In one aspect, the disclosure is directed to a power system for a vehicle; the vehicle includes a power bus, an energy storage pack, and an electric drive system. The power system includes one or more power conversion systems electrically connected in parallel to each phase of an electric motor of the electric drive system. Each power conversion system is electrically coupled to a set of energy storage modules of the energy storage pack. Each power conversion system includes a plurality of subsystem modules electrically coupled to provide a drive power output to the electric drive system and to provide an auxiliary power output to the power bus. Each subsystem module includes a power circuit and a power controller. The power circuit is electrically coupled to a selected subset of the energy storage modules of the set of energy storage modules and configured to provide a proportional drive power output and a proportional auxiliary power output to the power bus. The power controller is configured to control the power circuit to provide the proportional drive power output based on a desired power output of the electric drive system. The proportional drive power output from the plurality of subsystem modules is provided as a drive power output, and the proportional auxiliary power output from the plurality of subsystem modules is provided as an auxiliary power output.

[0020] In some variations, the power controllers for the subsystem modules are configured to obtain power set points for the respective power conversion systems based on a desired power output of the electric drive system; and determine a proportional drive power output provided by the power circuit to the electric drive system based on the power set points and the state of charge of the subset of the energy storage modules.

[0021] In one aspect, the disclosure is directed to a method for powering a vehicle electric drive system with a power system, the method including obtaining a desired power output of the power system; the power system including one or more power conversion systems each electrically coupled to a set of energy storage modules of a plurality of energy storage modules. For each power conversion system, the method further includes obtaining a state based on a state of charge of each energy storage module of the set of energy storage modules; and determining a power set point provided by the power conversion system of the set of energy storage modules and the desired power output.

[0022] The following includes variations of methods for powering a vehicle electric drive system with a power system, which may be implemented individually or in any combination.

[0023] In some variations, the method further includes determining, for each power conversion system, a virtual resistance based on a state of charge of the set of energy storage modules; the power set point is further determined based on the virtual resistance.

[0024] In some variations, the method further includes supplying power by the power system to the vehicle electric drive system based on the power setpoints; and determining an estimated state of charge of each energy storage module in response to supplying power to the vehicle electric drive system; subsequent power setpoints are determined based on the estimated state of charge.

[0025] In some variations, the method further includes, for each power conversion system, measuring a voltage applied to the vehicle electric drive system; and determining an estimated state of charge of the set of energy storage modules based on the applied voltage and a power set point; a subsequent power set point is determined based on the estimated state of charge.

[0026] In some variations, each power conversion system includes a plurality of subsystem modules electrically coupled to a subset of the energy storage modules of the set of energy storage modules. The method further includes obtaining, by each subsystem module, a power set point for the respective power conversion system; and determining, by each subsystem module of the respective power conversion system, a proportional drive power output provided by the subsystem module to the vehicle electric drive system based on the power set point and the state of charge of the subset of energy storage modules electrically coupled to the subsystem module.

[0027] In some variations, the method further includes measuring a current applied to the vehicle electric drive system in response to applying a proportional drive power output by each subsystem module of the plurality of subsystem modules; and determining an estimated state of charge of the subset of energy storage modules based on the applied current and a peak charge capacity of the subset of energy storage modules; the subsequent proportional drive power output is determined based on the estimated state of charge of the subset of energy storage modules.

[0028] In some variations, each power conversion system includes a plurality of subsystem modules electrically coupled to a subset of the energy storage modules of the set of energy storage modules. The method further includes obtaining, from each subsystem module of the plurality of subsystem modules, a state of charge of the subset of energy storage modules; determining a desired sequence of operation of the subsystem modules based on the obtained state of charge; selecting one or more subsystem modules of the plurality of subsystem modules as power output modules based on the desired sequence of operation and the power set points; determining, for each power output module, a proportional drive power set point to be provided to the vehicle electric drive system based on the power set point; and providing the proportional drive power set point to each power output subsystem module.

[0029] In some variations, the method further includes assigning a status to each power output module based on load demand and a state of the subset of energy storage modules; the status being selected from among actively on and actively switching on and off.

[0030] In some variations, the method further includes having a first set of power output modules provided with a status that is actively on during a selected period of time; meanwhile, a second set of power output modules, different from the first set of power output modules, is provided with a status that actively switches on and off during the selected period of time.

[0031] In some variations, the first set of power output modules and the second set of power output modules each include at least one power output module.

[0032] Further areas of applicability will become apparent from the description provided herein. It should be understood that this description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0033] In order that the present disclosure may be properly understood, various embodiments will now be described, given by way of example only, with reference to the accompanying drawings, in which:

[0034] [Figure 1] FIG. 1 is a block diagram of a vehicle having a power system according to the present disclosure. [Figure 2A] 1 illustrates a wiring configuration for a power system having multiple power conversion systems with electric motors of an electric drive system according to the present disclosure. [Figure 2B] 1 illustrates a wiring configuration for a power system having multiple power conversion systems with electric motors of an electric drive system according to the present disclosure. [Figure 2C]1 illustrates a wiring configuration for a power system having multiple power conversion systems with electric motors of an electric drive system according to the present disclosure. [Diagram 3] FIG. 1 is a block diagram of a power conversion system according to the present disclosure. [Figure 4] 1 illustrates an example power circuit of a power conversion system according to the present disclosure. [Diagram 5] 2 illustrates another embodiment of a power conversion system having multiple subsystem modules in accordance with the present disclosure. [Figure 6] FIG. 2 is a block diagram of a subsystem module according to the present disclosure. [Figure 7] 1 is an exemplary power circuit of a subsystem module according to the present disclosure. [Figure 8] 4 is a flow chart of an example control routine for a power conversion system according to the present disclosure. [Figure 9A] 4 is a flow chart of an example control routine for a power conversion system having multiple subsystem modules in accordance with the present disclosure. [Figure 9B] 4 is a flow chart of an example control routine for a power conversion system having multiple subsystem modules in accordance with the present disclosure. [Figure 10] 4 is a flow chart of another example of a control routine for a power conversion system having multiple subsystem modules in accordance with the present disclosure.

[0035] The figures described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The following description is merely exemplary in nature and is not intended to limit the disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0037] The present disclosure provides a power system having a modular power conversion structure for providing a drive power output to an electric drive system of a vehicle and for providing an auxiliary power output to one or more power buses. In one form, the power system includes one or more power conversion systems (PCS) having a power circuit and a power controller. As described herein, multiple PCSs can be coupled in series and / or parallel to provide power to the electric drive system and power bus(es) to provide a modular and / or scalable hardware design with distributed software control.

[0038] 1, among other components, a power system 100 of the present disclosure is provided in a vehicle 102. Among other components, the vehicle 102 includes an energy storage system 104, a power system 100, an electric drive system 106, and a power bus 108. For illustrative purposes only, solid lines 109 are provided to indicate power lines and dashed lines 111 are provided to indicate communication links. The power lines 109 are not intended to indicate actual physical circuits (e.g., wires, ports, circuits) and should not be interpreted to mean that the same power is provided, as will be apparent in the following description. With regard to the communication link 111, it should be readily understood that the systems in the vehicle 102, including the energy storage system, electricity, the electric drive system 100, and the electric drive system 106, can be communicatively coupled in a variety of suitable manners, such as, for example, wireless communication and / or wired communication.

[0039] The energy storage system 104 includes an energy storage controller 110, an energy storage pack 112 including a plurality of energy storage modules 114. The energy storage controller 110 is configured to monitor operational characteristics of the energy storage pack 112, such as, but not limited to, a state of charge of each of the energy storage pack 112 and the energy storage modules 114 and a temperature of the energy storage pack 112. In one form, the energy storage pack 112 may be provided as a battery pack having a plurality of battery modules / cells as the energy storage modules 114 to supply power to the power system 100.

[0040] The electric drive system 106 is configured to drive the vehicle in one or more directions and includes, among other components, a drive system controller 116 and one or more electric motors 118. The drive system controller 116 is configured to monitor the performance of the electric motor(s) 118 and determine a desired power output for the motor(s) 118 based on one or more operating conditions, such as, but not limited to, motor speed, torque, and safety conditions. The drive system controller 116 may be configured in a variety of suitable ways, such that one controller may be provided for each motor 118 or one controller may be configured to control multiple or all motors 118. The electric motor(s) 118 may be single-phase or multi-phase electric motors.

[0041] The power bus 108 is generally configured to provide direct current (DC) power to other electrical devices within the vehicle 102, such as, but not limited to, a heat pump, an electric power steering (EPS) pump, auxiliary outlets, and / or fans. In some variations, a vehicle may include multiple power buses 108 configured to provide the same and / or different DC power. For example, one power bus 108 may provide 12V DC and another power bus may provide 24V DC.

[0042] The power system 100 of the present disclosure is configured to provide a drive power output to the electric drive system 106 and an auxiliary power output to the power bus 108. In one form, the power system 100 includes multiple power conversion systems (PCS) 120-1, 120-2, 120-3 for providing power to the electric drive system 106 and the power bus 108. The PCSs 120-1, 120-2, 120-3 are collectively referred to as PCSs 120, and although three PCSs 120 are shown, the power system 100 may include one or more PCSs 120 and should not be limited to three. In one form, the number of PCSs 120 may be based on the design and / or requirements of the electric drive system 106 and / or the power bus(es) 108.

[0043] With respect to the electric drive system 106, "P" number of PCSs 120 are connected in parallel to power the same motor 118, or in another variation, "X" number of motors 118, where "X" is a number equal to or greater than one. For example, with reference to FIGS. 2A-2C, different wiring configurations are provided to illustrate various applications in which the power system 100 may be utilized. FIG. 2A illustrates a polyphase motor as the motor 118, and a power system 100 having a PCS 120 is provided to phase A. The PCSs 120 are connected in parallel to operate the electric motors 118 in a single star configuration. FIG. 2B illustrates a two-star configuration with two power systems 100A and 100B, each having multiple PCSs 120 connected in parallel to operate the electric motors 118. FIG. 2C illustrates a power system 100 having a PCS 120 connected in parallel to operate a single delta configuration electric motor 118. In FIG. 2A, FIG. 2B, and FIG. 2C, N is neutral, L1, L2, and L3 are optional inductors connected between the output of each PCS 120 and the terminals of the motor 118 to reduce circulating currents between the PCSs 120, and u a , u b , u c indicates voltage. It should be readily understood that for a multi-phase motor, each phase may include a power system 100 of the present disclosure, in other words, each phase may include one or more PCSs 120. The number of PCSs may vary from phase to phase.

[0044] In one form, each PCS 120 is electrically coupled to a set of energy storage modules 114 of the energy storage pack 112. For example, with reference to FIG. 1 , the PCS 120 is electrically coupled to a string of energy storage modules 114 as a set of energy storage modules. As provided herein, the power system 100 of the present disclosure may operate at various power levels (e.g., voltages) for the energy storage modules 114. Here, the term “set” of energy storage modules may include one or more energy storage modules 114.

[0045] 3 , in one form, each PCS 120 includes a power controller 200 and a power circuit 202. As described further herein, power controller 200 is configured to determine an amount of power to be provided by PCS 120 based on a desired power output and to control power circuit 202 to provide a drive power output to electric drive system 106. Power controller 200 may include various hardware and / or software components for performing operations as described herein, such as, but not limited to, a processor for executing a software program, a switch driver for operating power electronic switches, and a communication port for receiving and / or transmitting data to other controllers.

[0046] The power circuit 202 is electrically coupled to the set of energy storage modules 114 and configured to provide a drive power output to the electric motor 118 and an auxiliary power output to the power bus 108. In particular, in one form, the power circuit 202 includes a direct current-to-alternating current (DC-AC) inverter 204 configured to provide the drive power output and a direct current-to-direct current (DC-DC) converter 206 configured to provide the auxiliary power output. The DC-AC inverter 204 and the DC-DC converter 206 are electrically isolated from each other. In particular, at least one of the DC-AC inverter 204 and the DC-DC converter 206 includes an electrical isolation circuit to prevent feed-through faults between the converter terminals. In an application, the power circuit 202 may include magnetic isolation in the DC-DC converter 206 and / or other suitable electrical isolation circuitry, such as, but not limited to, inductive or capacitive isolation to separate the primary and secondary sides of the converter.

[0047] In some applications, the DC-DC converters of the power circuits of the multiple conversion systems may be electrically coupled to provide respective auxiliary power outputs to the power bus. For example, the DC-DC converters of the power circuits 202 of at least two of the multiple PCSs 120 are electrically coupled in series or parallel to provide respective auxiliary power outputs to the power bus 108. Thus, 48V may be provided to the power bus 108 by electrically coupling two 12V generating DC-DC converters in series. Also, if the vehicle 102 includes multiple power buses 108, the DC-DC converters 206 of the power conversion systems may be assigned to different power buses 108. For example, the DC-DC converters 206 of two PCSs 120 are electrically coupled to provide respective auxiliary power outputs to the first power bus 108, and the DC-DC converters 206 of the third PCS 120 are configured to provide respective auxiliary power outputs to the second power bus 108. In yet another example, the DC-DC converters 206 of the first PCS 120 are configured to provide respective auxiliary power outputs to the first power bus 108, and the DC-DC converters 206 of the second PCS 120 are configured to provide respective auxiliary power outputs to the second power bus 108. Thus, the power system 100 of the present disclosure may be configured in various suitable manners to supply power to one or more power buses 108 of the vehicle 102.

[0048] 4, a power circuit 300 is provided connected to a set of energy storage modules 302, which may be used as power circuit 202 and energy storage module 114, respectively. Power circuit 300 may be described as having a string of converters including a DC-AC inverter 304 that provides a drive power output to electric drive system 106, and a DC-DC converter 306 that provides an auxiliary power output to power bus 108. DC-AC inverter 304 and DC-DC converter 306 may be used as DC-AC inverter 204 and DC-DC converter 206. The drive power output is shown as arrow 308, and the auxiliary power output is shown as arrow 310.

[0049] In one form, the DC-AC inverter 304 is provided as a three-level inverter with power electronics comprised of power electronic switches, which may be metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), transistors, or gate turn-off thyristors (GTOs). The power electronic switches are operable by the power controller 200 to generate a desired drive power output. In one form, the DC-AC inverter 304 is provided as a bidirectional inverter, with output terminals connected to each other in a series and parallel configuration to provide power to the electric motor 118. It should be readily understood that the DC-AC inverter 304 may include additional and / or other components and should not be limited to the circuit configuration shown and provided in FIG. 4 . For example, the DC-AC inverter 304 may include filters and / or components to isolate the inverter 304 from the DC-DC converter 306.

[0050] The DC-DC converter 306 is provided as an isolated converter having electronics such as, but not limited to, a flyback converter, a half-bridge circuit, a full-bridge circuit, and / or an inductor and capacitor. In FIG. 4, the DC-DC converter 306 provides a regulated DC output at a 12V or 48V level. However, as discussed above, the DC-DC converter 306, either individually or in conjunction with other DC-DC converters 306, may be configured in a variety of suitable ways to provide auxiliary power output(s) to one or more power buses 108 and should not be limited to the configuration shown in the figure. In one form, the DC-DC converter 306 is a bidirectional converter. It should be readily understood that the DC-DC converter 306 may include additional and / or other components and should not be limited to the circuit configuration shown and provided in FIG. 4. For example, the DC-DC converter 306 may include a filter and / or may not include components to isolate the converter 306 from the DC-AC inverter 304.

[0051] In one form, the number of energy storage modules 114 contributing power to a power bus 108 may be directly proportional to the total power consumption of that power bus 108 compared to the total power consumption of all power buses 108. Thus, an energy storage module 114 of the plurality of energy storage modules may or may not contribute power to one or more of the power buses 108.

[0052] Each PCS 120 in FIG. 3 includes a three-level DC-AC inverter for generating drive power output to the electric drive system 106. Referring to FIG. 5 and FIG. 6, in another embodiment, the power system 100 of the present disclosure may include multiple PCSs 400-1, 400-2, and 400-3 (collectively "PCSs 400") connected in parallel in phase, each having a multi-level modular converter configuration. In particular, each PCS 400 includes multiple subsystem modules (SMs) 402, each SM 402 including a power controller 404 and a power circuit 406. In other words, each SM 402 may be considered a PCS 120, and multiple PCSs 120 are connected in series to form a string of the conversion system 120. Although multiple PCSs 400 are shown, the number of PCSs 400 may be one or more, and the number of SMs 402 per PCS 400 may be two or more. Also, when multiple PCSs 400 are present, the number of SMs 402 may be the same or different among the PCSs 400. In one form, the number of PCSs 400 and the number of SMs 402 for a selected PCS 400 may be based on the design and / or requirements of the electric drive system 106 and / or power bus(es) 108.

[0053] Similar to the power circuit 202, the power circuit 406 of the SM 402 includes a DC-AC inverter 408 and a DC-DC converter 410. The power circuit 406 of the SM 402 is configured to provide a proportional drive power output and a proportional auxiliary power output. The proportional drive power output from the power circuit of the multiple SMs 402 is provided as a drive power output from the respective PCS 400, and the proportional auxiliary power output from the power circuit 406 of the multiple SMs 402 is provided as an auxiliary power output from the respective PCS 400.

[0054] Similar to the PCS 120, each PCS 400 is electrically coupled to a set of energy storage modules 114 of the energy storage pack 112. Each SM 402 is electrically coupled to a subset of the energy storage modules 114 of the set of energy storage modules. In particular, with reference to FIG. 7, the power circuit 406 for the SM 402 may be implemented using the electrical circuit 300, but is electrically coupled to a subset of the energy storage modules 114, generally identified by reference number 420. That is, the DC-AC inverter 408 may be implemented with the DC-AC inverter 304, and the DC-AC inverters 408, 304 of the PCS 400 are electrically coupled to each other in series and / or parallel. The DC-DC converter 410 may be implemented with the DC-DC converter 306, and the DC-DC converters 410 of the PCS 400 are electrically coupled to each other in series and / or parallel. For the configuration of PCS 400, the DC-DC converter 306 outputs a proportional auxiliary power output identified by arrow 422, and the DC-AC inverter outputs a proportional drive power output identified by arrow 424. The subset of energy storage modules may include one or more energy storage modules / cells.

[0055] Similar to PCS120, PCS400 may be wired such that the auxiliary power output from PCS400 is provided to a single power bus 108 or may be electrically coupled to terminals of one or more other PCSs400 (e.g., the terminals are connected in parallel and / or in series) to provide respective auxiliary power outputs to one or more power buses 108.

[0056] PCS 400 provides a scalable and modular multi-level power system architecture for regulating both drive power output to electric drive system 106 (e.g., to one or more electric motors) and auxiliary power output to one or more power buses 108. That is, PCS 400 is designed to generate multiple DC and AC power outputs using distributed DC-DC converters 410 and DC-AC inverters 408.

[0057] In the variations described herein, the power system 100 may include one or two levels of control. For example, the first level may be power conversion control and the optional second level may be sub-module control. The power conversion control may include multiple controllers, each controller controlling a given PCS 120, 400. For example, for the PCS 120, the power controller 200 may form the power conversion control for the power system 100. The optional sub-module control is used with the subsystem modular configuration of the PCS 400, and the number of module controllers may be equal to the number of SMs 402. For example, the power controller 404 may form the second level of sub-module control. For a power system 100 having a PCS 400, the first level of control may be provided as a controller for each PCS 400. For example, FIG. 6 shows a PCS controller 430 communicatively coupled to the SMs 402. In one form, each PCS 400 includes a dedicated PCS controller 430 for communicating with each power controller 404 of the SMs 402 of the PCS 400, thereby forming a two-level control. In another form, the operation of the power controllers 404 of the multiple SMs 402 are implemented in the PCS controller 430, thereby eliminating the dedicated power controllers 404 for the SMs 402 and providing a single level control of the PCS 400.

[0058] In an exemplary implementation, the drive system controller 116 of the electric drive system 106 is configured to obtain one or more operating conditions of the motor 118 and determines a desired power output of the electric drive system 106 to be provided to the power system 100. For example, the drive system controller 116 receives a desired motor speed and determines a speed error based on the desired speed, which is provided to a closed loop control, such as, but not limited to, proportional-integral (PI) control and / or predictive model control. Based on the closed loop control, the drive system controller 116 is configured to determine a desired torque and, using other control models, determines a reference current flowing through the electric motor and / or a reference voltage applied to the electric motor. The reference voltage may be expressed in a DQ rotating reference frame that indicates the magnitude of a reference AC signal having the same frequency and phase as the back electromotive force (Q component) and the magnitude of another AC voltage (D component) having a phase shift of 90 degrees from the Q component to generate the reference AC voltage. The Q component and D component may be used for single-phase and multi-phase systems as the desired power output. The Q and D components may be the result of a three-phase rotating vector, where the D vector is an axis that may be generated from the three phases that are phase shifted 90 degrees from the components that generate the Q vector. The values ​​of the Q and D components may be provided to the power system 100 as a desired power output. A reference current and / or a reference voltage are also examples of a desired power output.

[0059] The above-described example of how the drive system controller 116 determines the desired power output based on operating conditions is just one example using one condition (e.g., motor speed). It should be readily understood that the drive system controller 116 typically uses complex control schemes to determine the desired power output based on multiple variables and operating conditions. The power system 100 of the present disclosure may be used with such a drive system controller 116 to provide the required power to the electric motor 118.

[0060] With respect to the PCSs 120, each PCS 120 receives a desired power output for the electric motor 118, and a power controller 200 of the PCS 120 is configured to determine a power setpoint provided by the PCS 120 based on the desired power output and the state of charge (SOC or SoC) of the set of energy storage modules 114. For example, the power controller 200 may receive values ​​of the Q and D voltages as the desired power output, and the power controller 200 estimates or calculates the SOC of the set of energy storage modules 114 electrically coupled to the power circuit 202. In one form, the power controller 202 determines the output voltage (

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[0070] In an exemplary application, the power set point is provided as a reference current provided by the PCS 400. The SM module 402, and in particular the power controller 404, determines the current output (

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[0083] The k-th PCS controller 430 is connected to the equivalent SoC (SoC k ) and the number of SM402 in the PCS (N k ) to obtain the voltage according to (7) below.

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[0106] The PCS controller operates at steady state out V ref Until it matches

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[0109] 8, an example control routine 500 for the PCS 120, and in particular for providing power to the electric drive system 106, is provided. At 502, the PCS 120 obtains a desired power output for the electric drive system (EDS) 106. As discussed above, the desired power output may be provided in a variety of forms, such as, but not limited to, a reference voltage, a reference current, etc., and is determined based on one or more operating conditions of the electric drive system 106. At 504, using known methods, the PCS 120 determines the SOC or equivalent SOC of the set of energy storage modules 114 to which the PCS 120 is connected. At 506, the PCS 120 calculates a virtual resistance (R vir ) required value. For example, R vir =K / SOC, where K is a global constant used by each PCS 120. At 508, the PCS 120 is configured to obtain a value of the current provided by the PCS 120. For example, the PCS 120 may obtain the current (i inv At 510, the PCS 120 is configured to determine a power setpoint to be applied by the PCS 120 and then apply power to the electric drive system 106. For example, the power setpoint v inv may be provided, v inv =V ref -(i inv ×R vir ), where V ref is the desired power output. The PCS 120 may continue the control routine 500 until, for example, the power to the vehicle is turned off.

[0110] 9A and 9B, exemplary control routines 600 and 650 are provided for a power system 100 having a PCS 400, where control routine 600 is executed by the PCS controller 430 and routine 650 is executed by each SM 402 of the PCS 400 via the power controller 404. With respect to routine 600, the PCS controller 430 initializes an equivalent SOC of each PCS 400 at 602, where SOC=1. Steps 604, 606, and 608 are similar to steps 502, 506, and 508 of FIG. 5. Specifically, at 604, the PCS 120 obtains a desired power output for the electric drive system (EDS) 106, and at 606, the PCS 120 calculates a virtual resistance (R vir ) and at 608, the PCS 120 is configured to obtain a value of the current provided by the PCS 120. At 610, the PCS controller 430 is configured to determine a power setpoint to be applied by the PCS 400 based on at least the desired power output and the SOC. For example, the PCS controller 430 may set the inverter voltage to v inv =V ref -(i inv ×R vir ) and then set the voltage based on the number of modules as v c =V inv / (N * SOC), where N is the number of SMs 402 provided to the PCS 400. In 612, the PCS controller 430 assigns a power setting of “v c At 614, the PCS 230 estimates the SOC of the set of energy storage modules 114 coupled to the PCS 400. For example, the PCS 230 may estimate the voltage applied in the current power cycle as “v A " or SOC = v A / (v C * N). The estimated SOC is used to determine subsequent power settings.

[0111] 9B , using the power setpoint of the PCS 400, each SM 402 of the PCS 400 is configured to perform a routine 650 to determine a proportional drive power output provided by the SM 402 to the electric drive system 106. At 652, the SM 402 is configured to initialize the SOC or determine the SOC of a subset of the energy storage modules 114 coupled to the SM 402. At 654, the SM 402 is configured to determine a proportional drive power output based on the power setpoint and the SOC of the subset of the energy storage modules 114. For example, the proportional drive power output may be determined by a voltage "v op " may be provided as op =v C * At 656, a proportional drive power output is provided to the electric drive motor 118 and the current supplied to the electric drive motor is measured (the supplied current is "i"). At 658, the SM 402 is configured to estimate the SOC of the subset of energy storage modules. For example, the SOC may be estimated by (17) below, where "i" is the supplied current and C is the peak charge capacity of the subset of energy storage modules 114. The estimated SOC is used to determine the proportional drive power output for subsequent power determinations.

[0112]

number

[0113] In another variation, if each SM 402 is capable of transmitting data to the PCS controller 430 (i.e., there is two-way communication between the PCS controller 430 and the SMs 402), the PCS controller 430 may obtain data indicative of the SOC of a subset of the energy storage modules of each SM 402 and then selectively operate the SMs 402 based on the SOC. For example, FIG. 10 illustrates a control routine 700 executed by the PCS controller 430 capable of receiving data indicative of the SOC from the SMs 402 of the PCS 400. Portions of the control routine 700 are similar to portions of the control routine 600, and therefore steps described in the routine 700 that are the same as steps of the routine 600 will not be described in detail. At 702, the PCS controller 430 is configured to obtain from the SMs 402 the SOC of the subset of the energy storage modules coupled to each of the SMs 402 and determine at 704 a desired order of operation of the SMs 402. In particular, the PCS controller 430 sorts the list of SMs 402 based on the SOC associated with each SM 402. At 706, similar to routine 500, PCS controller 430 sets the power setting of PCS 400 to v inv =V ref -(i inv ×R vir ) is determined.

[0114] Using information related to the SOC of the SMs 402, the PCS controller 430 is configured to select SMs 402 for powering the electric drive system. Specifically, at 708, the PCS controller 430 selects one or more SMs 402 from among the SMs 402 of the PCS 400 as power output modules based on a desired order of operation and power setpoints. For example, the PCS controller 430 may select how many SMs 402 are fully on (F) to achieve the power setpoint. ON ) or F ON =fix(v inv / B), where B is the maximum power of the SM 402. The PCS controller 430 also determines the remaining power required to reach the power setpoint. For example, the remaining voltage (V_rem) as the remaining power is given by: V_rem=rem(v inv / B). At 710, the PCS 230 transmits the power setpoint to the power output module. Upon receipt, the SM 402 selected as the power output module is configured to operate similarly to that described in routine 9B, with the primary difference being that the SM transmits the estimated SOC to the PCS 230.

[0115] In some variations in which the SM 402 has bidirectional communication with the PCS 400, the PCS controller 430 is further configured to selectively operate the power output modules 402 such that one or more of the power output modules 402 are switched on and off at a time to improve switching frequency. In particular, the PCS controller 430 is configured to assign a status to each power output module based on, for example, the load demand of the electric drive system and the state of the subset of energy storage modules. That is, for a selected time period, the status indicates whether the power output module is actively on or actively switching on and off. The state of the subset of energy storage modules includes the health of the energy storage modules, the SOC of the subset of energy storage modules, and / or performance characteristics of the subset of energy storage modules 114, such as, for example, temperature. Thus, for a selected time period, a first set of power output modules is provided with a status of actively on and a second set of power output modules, different from the first set of power output modules, is provided with a status of actively switching on and off. In other words, while a first set of power output modules is actively on, a second set of power output modules actively switches on and off to provide a drive power output during a selected period of time.

[0116] In one form, PCS 120 and PCS 400 may be used in combination with each other to form power system(s) 100. For example, vehicle 102 may include a power system having PCS 120 for a first motor and another power system having PCS 400 for a second motor. Both PCSs 120 and 400 may be used to power the same motor.

[0117] It should be readily understood that the exemplary routines of Figures 8, 9A, 9B, and 10 are provided as examples, and that the control routines may be configured in other suitable manners for controlling power to an electric drive system.

[0118] The power system of the present disclosure may provide a modular and / or scalable hardware design with distributed software control. In some applications, the power system may not require filtering, thereby reducing system size and complexity. The control methods described herein may increase the capacity of an energy storage module and / or the driving range of a vehicle by enabling active and / or selective management of the power conversion system. These and other advantages may be provided by the power system of the present disclosure.

[0119] In this disclosure, the term "obtaining" may include at least receiving from another device, calculating based on received data, and / or determining based on a software application.

[0120] Unless otherwise expressly stated herein, all numerical values ​​expressing mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are understood to be modified by the word "about" or "approximately" in describing the scope of the present disclosure. This modification is desirable for a variety of reasons, including industrial practices, material, manufacturing, and assembly tolerances, and test performance.

[0121] As used herein, the phrase at least one of A, B, and C should be construed to mean logical (A or B or C) using a non-exclusive logical OR, and not to mean "at least one of A, at least one of B, and at least one of C."

[0122] In this application, the term "controller" may refer to, be part of, or include an application specific integrated circuit (ASIC), digital, analog, or mixed analog / digital discrete circuitry, digital, analog, or mixed analog / digital integrated circuit, combinatorial logic circuitry, a field programmable gate array (FPGA), a processor circuit (shared, dedicated, or group) that executes code, a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuitry, other suitable hardware components that provide the described functionality (e.g., an op-amp circuit integrator as part of a heat flux data module), or a combination of some or all of the above, such as in a system on a chip.

[0123] The term memory is a subset of the term computer-readable medium. As the term computer-readable medium is used herein, it does not include a transitory electrical or electromagnetic signal propagating through a medium (e.g., on a carrier wave), so the term computer-readable medium may be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media are non-volatile memory circuits (e.g., flash memory circuits, erasable programmable read-only memory circuits, or masked read-only circuits), volatile memory circuits (e.g., static random access memory circuits or dynamic random access memory circuits), magnetic storage media (e.g., analog or digital magnetic tape or hard disk drives), and optical storage media (e.g., CDs, DVDs, Blu-ray discs, etc.).

[0124] The apparatus and methods described in this application may be implemented in part or in whole by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The functional blocks, flowchart components, and other elements described above serve as software specifications that can be rewritten into a computer program by the routine work of a professional engineer or programmer.

[0125] Because the description of the disclosure is merely exemplary in nature, variations that do not depart from the essence of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as departures from the spirit and scope of the disclosure.

Claims

1. 1. An electric power system for a vehicle; the vehicle including an electric power bus, an electric drive system, and an energy storage pack; the electric power system including: one or more power conversion systems electrically connected in parallel to each phase of an electric motor of the electric drive system; each power conversion system electrically coupled to a set of energy storage modules of the energy storage pack; each power conversion system: a power circuit electrically coupled to each set of energy storage modules and configured to provide a drive power output to the electric drive system and to provide an auxiliary power output to the power bus; and a power controller configured to control the power circuit to provide the drive power output based on a desired power output of the electric drive system; and Including, Power system.

2. the power circuit includes a three-level direct current to alternating current (DC-AC) inverter configured to provide the drive power output; The power system of claim 1 .

3. the power circuitry includes a direct current-to-direct current (DC-DC) circuitry configured to provide the auxiliary power output to the power bus; The power system of claim 1 .

4. the DC-DC converters of the power circuits of at least two of the one or more power conversion systems are electrically coupled in series to provide respective auxiliary power outputs to the power bus. The power system of claim 3 .

5. the DC-DC converters of the power circuits of at least two of the one or more power conversion systems are electrically coupled in parallel to provide respective auxiliary power outputs to the power bus. The power system of claim 3 .

6. the vehicle includes a plurality of power buses; the DC-DC converters of the power circuits of at least two of the one or more power conversion systems are electrically coupled to provide respective auxiliary power outputs to a first power bus of the plurality of power buses; the DC-DC converter of the power circuit of a third power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a second power bus of the plurality of power buses; The power system of claim 3 .

7. The power circuit includes: a three-level direct current to alternating current (DC-AC) inverter configured to provide the drive power output; and a direct current to direct current (DC-DC) circuit configured to provide the auxiliary power output to the power bus; and Including, The DC-AC inverter and the DC-DC converter are electrically insulated from each other. The power system of claim 1 .

8. the vehicle includes a plurality of said power buses; the power circuit of a first power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a first power bus of the plurality of power buses; the power circuit of a second power conversion system of the one or more power conversion systems is configured to provide a respective auxiliary power output to a second power bus of the plurality of power buses; The power system of claim 1 .

9. each power conversion system includes a plurality of the power circuits and a plurality of the power controllers forming a plurality of subsystem modules configured to provide the drive power output and the auxiliary power output; Each of the plurality of subsystem modules comprises: a power circuit of the plurality of power circuits electrically coupled to a selected subset of energy storage modules from the set of energy storage modules; and a power controller of the plurality of power controllers configured to control the one power circuit; and Including, The power system of claim 1 .

10. The power controller of the power conversion system includes: obtaining a desired power output based on operating conditions of the electric drive system; determining a state of charge of each energy storage module of the set of energy storage modules; determining a power setpoint to be provided by the power conversion system based on the desired power output and the state of charge of the set of energy storage modules; It is configured as follows: The power system of claim 1 .

11. the power controller is configured to determine a virtual resistance based on the state of charge of the set of energy storage modules; and the power set point is further determined based on the virtual resistance.

11. The power system of claim 10.

12. the power controller is configured to determine an estimated state of charge of each energy storage module in response to the drive power output being applied to the electric drive system; and a subsequent power set point is determined based on the estimated state of charge.

11. The power system of claim 10.

13. an electric drive system including an electric motor; and The power system of claim 1 , wherein the one or more power conversion systems are provided for each phase of the electric motor; and A system comprising:

14. 1. An electric power system for a vehicle; the vehicle including an electric power bus, an energy storage pack, and an electric drive system; the electric power system including: one or more power conversion systems electrically connected in parallel to each phase of an electric motor of the electric drive system; each power conversion system electrically coupled to a set of energy storage modules of the energy storage pack; each power conversion system: a plurality of subsystem modules electrically coupled to provide a drive power output to the electric drive system and to provide an auxiliary power output to the power bus; each subsystem module comprising: a power circuit electrically coupled to a selected subset of the set of energy storage modules and configured to provide a proportional drive power output and a proportional auxiliary power output to the power bus; and a power controller configured to control the power circuit to provide the proportional drive power output based on a desired power output of the electric drive system; and Including, the proportional drive power output from the plurality of subsystem modules is provided as the drive power output; the proportional auxiliary power output from the plurality of subsystem modules is provided as the auxiliary power output; Power system.

15. The power controller for a subsystem module comprises: obtaining a power setpoint for each power conversion system based on the desired power output of the electric drive system; determining the proportional drive power output provided by the power circuit to the electric drive system based on the power setpoint and a state of charge of the subset of energy storage modules; It is configured as follows:

15. The power system of claim 14.

16. 1. A method for powering a vehicle electric drive system with an electrical power system, comprising: obtaining a desired power output of the power system; the power system being one or more power conversion systems; each power conversion system electrically coupled to a set of energy storage modules of a plurality of energy storage modules; and For each power conversion system: obtaining a state of charge of each energy storage module of the set of energy storage modules; and determining a power setpoint provided by the power conversion system based on the desired power output and the state of charge of the set of energy storage modules; and A method for providing the above.

17. determining, for each power conversion system, a virtual resistance based on the state of charge of the set of energy storage modules; the power set point is further determined based on the virtual resistance.

17. The method of claim 16.

18. supplying power by the power system to the vehicle electric drive system based on the power setpoint; and determining an estimated state of charge of each energy storage module in response to supplying power to the vehicle electric drive system; a subsequent power set point is determined based on the estimated state of charge; and Further comprising:

17. The method of claim 16.

19. For each power conversion system: measuring a voltage applied to the vehicle electric drive system; and determining an estimated state of charge of the set of energy storage modules based on the applied voltage and the power set point; a subsequent power set point is determined based on the estimated state of charge; and Further comprising:

17. The method of claim 16.

20. Each power conversion system includes a plurality of subsystem modules electrically coupled to a subset of energy storage modules of the set of energy storage modules; and the method further comprises: obtaining, by each subsystem module, the power setpoint of the respective power conversion system; and determining, by each subsystem module of the respective power conversion system, a proportional drive power output provided by the subsystem module to the vehicle electric drive system based on the power setpoint and a state of charge of a subset of the energy storage modules electrically coupled to the subsystem module; and Further comprising:

17. The method of claim 16.

21. by each of the plurality of subsystem modules measuring a current applied to the vehicle electric drive system in response to applying the proportional drive power output; and determining an estimated state of charge of the subset of energy storage modules based on the applied current and a peak charge capacity of the subset of energy storage modules; a subsequent proportional drive power output is determined based on the estimated state of charge of the subset of energy storage modules; and Further comprising:

21. The method of claim 20.

22. Each power conversion system includes a plurality of subsystem modules electrically coupled to a subset of energy storage modules of the set of energy storage modules; and the method further comprises: obtaining a state of charge of the subset of energy storage modules from each subsystem module of the plurality of subsystem modules; and determining a desired sequence of operation of the subsystem modules based on the obtained state of charge; and selecting one or more subsystem modules of the plurality of subsystem modules as power output modules based on the desired operating sequence and the power setpoints; and determining, for each power output module, a proportional drive power setpoint to be provided to the vehicle electric drive system based on the power setpoint; and providing the proportional drive power setpoint to each of the power output subsystem modules; and Further comprising:

17. The method of claim 16.

23. assigning a status to each power output module based on load demand and a state of the subset of energy storage modules; the status being selected from among actively on and actively switching on and off; 23. The method of claim 22.

24. having a first set of power output modules provided with a status of actively on during a selected time period; while a second set of power output modules different from the first set of power output modules is provided with a status of actively switching on and off during the selected time period; 24. The method of claim 23.

25. each of the first set of power output modules and the second set of power output modules includes at least one power output module; 25. The method of claim 24.

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