Motor system control

Abstract

The motor system includes a rechargeable energy storage system, an AC motor, and a power inverter. A plurality of efficiency maps may be provided, each efficiency map representing a particular combination of control parameters and associated settings. The map decorrelates the operating space (torque and speed) of the motor with the corresponding efficiency. A combination of control parameters and settings that produce the highest motor system efficiency at the operating point may be determined from multiple efficiency maps and used to control the motor.

Description

Background Art

[0001] An electrified vehicle may include an alternating current (AC) motor system for providing propulsion torque to a powertrain system of the vehicle. The motor system may include a rechargeable energy storage system, an AC motor, and a power inverter for converting direct current (DC) electrical power to AC electrical power to operate the AC motor. The motor system may be configured with multiple parameters that may be controlled in various settings, each of which may affect the efficiency of associated components and / or the overall motor system efficiency. Even a relatively small number of controllable parameters and settings may represent a large number of potential combinations that present control challenges for achieving the most efficient overall motor system operation over the entire operating space of the AC motor. Summary of the invention

[0002] In an exemplary embodiment, a method for controlling a motor system including a rechargeable energy storage system (RESS), an alternating current (AC) motor, and a power inverter therebetween may include: providing a plurality of efficiency maps for control use considerations, each efficiency map corresponding to a respective predetermined combination of at least two motor system control parameters, and associating a motor operating space in motor torque and motor speed with a respective motor system efficiency solution, wherein at least one of the at least two motor system control parameters includes at least two respective optional settings; receiving a motor speed signal; receiving a motor torque command; determining from the plurality of efficiency maps a respective predetermined combination of the at least two motor system control parameters associated with a highest motor system efficiency solution at a motor operating point corresponding to the motor speed signal and the motor torque, and controlling the motor based on the respective predetermined combination of the at least two motor system control parameters.

[0003] In addition to one or more features described herein, motor system control parameters may include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency of the power inverter, gate drive parameters of the power inverter, and a direct current (DC) link voltage provided by the RESS to the power inverter.

[0004] In addition to one or more features described herein, a pulse width modulation (PWM) scheme can include a first corresponding optional setting and a second corresponding optional setting, the first corresponding optional setting being space vector pulse width modulation, and the second corresponding optional setting being one of generalized discontinuous pulse width modulation and fractional duty cycle pulse width modulation.

[0005] In addition to one or more features described herein, the switching frequency can include a first corresponding selectable setting as the first frequency and a second corresponding selectable setting as the second frequency, wherein the second frequency is a multiple of the first frequency.

[0006] In addition to one or more features described herein, the gate drive parameters may include a first corresponding selectable setting as a first gate resistance and a second corresponding selectable setting as a second gate resistance, wherein the second gate resistance is greater than the first gate resistance.

[0007] In addition to one or more features described herein, the DC link voltage may include a first corresponding selectable setting as the first voltage and a second corresponding selectable setting as the second voltage, wherein the second voltage is a multiple of the first voltage.

[0008] In addition to one or more of the features described herein, the motor system control parameters may include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency for the power inverter, gate drive parameters for the power inverter, and a direct current (DC) link voltage provided by the RESS to the power inverter.

[0009] In addition to one or more features described herein, all of the at least two motor system control parameters may include at least two respective selectable settings.

[0010] In addition to one or more features described herein, each efficiency graph can be reduced by utilizing a Pareto front analysis that takes into account a set of motor system optimization objectives to eliminate corresponding motor system efficiency solutions within the motor operating space of motor torque and motor speed that are dominated by motor system efficiency solutions within the motor operating space of motor torque and motor speed of other efficiency graphs.

[0011] In addition to one or more features described herein, the set of motor system optimization objectives may include a first metric of noise, vibration, and harshness, a second metric of motor bearing life, and a third metric of RESS life.

[0012] In addition to one or more features described herein, at least one of the plurality of efficiency maps may be withdrawn from control consideration based on a determined unacceptable impact on at least one of a set of motor system efficiency trade-off objectives at a motor operating point.

[0013] In addition to one or more features described herein, the set of motor system efficiency tradeoff objectives may include a first metric of noise, vibration, and harshness, a second metric of motor bearing life, and a third metric of RESS life.

[0014] In another exemplary embodiment, a method of controlling a motor system including a rechargeable energy storage system (RESS), an alternating current (AC) motor, and a power inverter therebetween may include: providing a plurality of efficiency maps for control use consideration, each efficiency map corresponding to a respective predetermined combination of at least two motor system control parameters and associating a motor operating space of motor torque and motor speed with a respective motor system efficiency solution, wherein at least one of the at least two motor system control parameters includes at least two respective optional settings; establishing a motor operating point corresponding to a motor speed signal and a motor torque command; withdrawing the respective efficiency map from control use consideration based on its determined unacceptable impact on at least one of a set of motor system efficiency trade-off objectives at the motor operating point, determining from the plurality of efficiency maps available for control use respective predetermined combinations of at least two motor system control parameters associated with a highest motor system efficiency solution for the motor operating point, and controlling the motor based on the respective predetermined combinations of the at least two motor system control parameters.

[0015] In addition to one or more features described herein, motor system control parameters may include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency of the power inverter, gate drive parameters of the power inverter, and a direct current (DC) link voltage provided by the RESS to the power inverter.

[0016] In addition to one or more features described herein, each efficiency map may be reduced by eliminating corresponding motor system efficiency solutions dominated by motor system efficiency solutions of other efficiency maps using a Pareto front analysis that considers a set of motor system optimization objectives.

[0017] In addition to one or more features described herein, the set of motor system optimization objectives may include a first metric of noise, vibration, and harshness, a second metric of motor bearing life, and a third metric of RESS life.

[0018] In addition to one or more of the features described herein, the motor system control parameters may include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency for the power inverter, gate drive parameters for the power inverter, and a direct current (DC) link voltage provided by the RESS to the power inverter.

[0019] In addition to one or more features described herein, all of the at least two motor system control parameters may include at least two respective selectable settings.

[0020] In yet another exemplary embodiment, an electrified powertrain may include: a rechargeable energy storage system (RESS); a traction power inverter module (TPIM) connected to the RESS and configured to change a direct current (DC) voltage from the RESS to a multi-phase alternating current (AC) voltage; a rotary motor excited by a multi-phase AC voltage from the TPIM via a multi-phase AC bus, the multi-phase AC bus including a stator having a multi-phase AC stator winding, a rotor, and a rotor shaft, the rotor shaft connected to and surrounded by the rotor, and configured to rotate with the rotor about a rotation axis when the rotary motor is excited; a transmission coupled to the rotor shaft and powered by the rotary motor; and a controller, the controller providing a plurality of efficiency maps for control consideration, each efficiency map corresponding to a respective predetermined combination of a plurality of motor system control parameters and associating a motor operating space of motor torque and motor speed with a corresponding motor system efficiency solution, wherein each of the plurality of motor system control parameters includes at least two respective an optional setting; establishing a motor operating point corresponding to a motor speed signal and a motor torque command; withdrawing a corresponding efficiency map from consideration for control use based on its determined unacceptable impact on at least one of a set of motor system efficiency trade-off objectives at the motor operating point; reducing each efficiency map by eliminating corresponding motor system efficiency solutions dominated by motor system efficiency solutions of other efficiency maps using a Pareto front analysis that takes into account corresponding values ​​of a set of motor system optimization objectives; considering respective predetermined combinations of multiple motor system control parameters, determining, from a plurality of reduced efficiency maps available for control use, respective predetermined combinations of multiple motor system control parameters associated with one of the following: a) a highest motor system efficiency solution at the motor operating point; b) a highest optimization score from an optimization equation performed for a set of motor system optimization objectives, the set of motor system optimization objectives corresponding to each reduced efficiency map having a corresponding non-dominated solution at the motor operating point; and controlling the motor according to respective predetermined combinations of multiple motor system control parameters.

[0021] In addition to one or more features described herein, the set of motor system efficiency trade-off objectives and the set of motor system optimization objectives can each include a corresponding first metric of noise, vibration, and harshness, a corresponding second metric of motor bearing life, and a corresponding third metric of RESS life.

[0022] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:

[0024] Figure 1 An electric propulsion system on a vehicle is shown according to one or more embodiments;

[0025] Figure 2A-2C illustrates an exemplary motor system efficiency graph for respective combinations of motor system control parameters and respective settings according to one or more embodiments;

[0026] Figure 3A and 3B The diagrams respectively show the corresponding merged Figure 2A-2C Exemplary three-dimensional and two-dimensional efficiency plots of;

[0027] Figure 4A and 4B illustrates an exemplary motor system efficiency graph for respective combinations of motor system control parameters and respective settings according to one or more embodiments; and

[0028] Figure 5 An exemplary implementation of motor system control according to one or more embodiments is shown. DETAILED DESCRIPTION

[0029] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. Throughout the drawings, corresponding reference numerals indicate identical or corresponding parts and features. The description of components and features in one drawing is understood to apply to components and features in other drawings sharing the same reference numerals, as long as such components and features cannot be otherwise distinguished by one of ordinary skill in the art through inspection of the drawings or through additional written descriptions herein.

[0030] Figure 1 An embodiment of an electric propulsion system 101 on an electrified vehicle 100 is schematically shown. Vehicles and vehicles are understood to refer to any means of transportation, including non-limiting examples motorcycles, automobiles, trucks, buses, excavation, earthmoving, construction and farming equipment, rail vehicles (such as trains and trams), and watercraft (such as ships and boats). The electric propulsion system 101 may include various control components, electrical systems, and electromechanical systems, including, for example, a rechargeable energy storage system (RESS) 104 and an electric drive unit (EDU) 102. The electric propulsion system 101 may be used on a powertrain system to generate propulsion torque, as a replacement for or in combination with an internal combustion engine in various electric vehicle (EV) applications and hybrid electric vehicle (HEV) applications, respectively.

[0031] The EDU 102 may have varying complexity, components, and integration. An exemplary highly integrated EDU 102 may include, for example, a rotating electrical machine such as an alternating current (AC) motor (motor) 120 and a traction power inverter module (TPIM) 106 (including a motor controller 105 and a power inverter 110). The motor 120 may include a stator 120S and a rotor 120R, which are coupled to a rotor shaft 125 and a position sensor 182, such as a variable reluctance resolver or encoder. The position sensor 182 may be directly signal-connected to the motor controller 105 and used to monitor the angular position (θe) of the rotor of the motor 120. The motor controller 105 uses the angular position (θe) of the rotor of the motor 120 to control the operation of the power inverter 110, which controls the torque generation and other functions of the motor 120, including the first-order derivative quantity of the angular velocity (i.e., the motor speed).

[0032] The rotor shaft 125 can transfer torque between the motor 120 and the drive train components, some of which can be integrated within the EDU 102, such as in a gearbox 121 that includes a reduction and differential gear set and one or more shaft outputs. The gearbox 121 can simply include a reduction gear arrangement and a drive shaft output for coupling to the differential gear set. One or more shafts 123 can be directly coupled to the gearbox 121, or if separated from the gearbox 121, then coupled to the gearbox 121 through a final drive or differential gear set. The shaft 123 can be coupled to one or more wheels 124 for transmitting traction between the wheels and the road surface. Those of ordinary skill in the art will recognize alternative arrangements of the drive train components. Propulsion torque request or command 136 (T cmd ) may be provided by the vehicle controller 103 to the motor controller 105 as discrete inputs on a network bus, such as a CAN bus.

[0033] Any controller may include one or more control modules. As used herein, control module, module, control, controller, control unit, electronic control unit, processor and similar terms mean an application specific integrated circuit (ASIC), an electronic circuit, a central processing unit (preferably, a microprocessor) and associated memory and storage devices (read-only memory (ROM), random access memory (RAM), electrically programmable read-only memory (EPROM), hard disk drive, etc.) or a microcontroller that executes one or more software or firmware programs or routines, a combinational logic circuit, an input / output circuit and device (I / O) and appropriate signal conditioning and buffering circuits, high-speed clocks, analog-to-digital (A / D) and digital-to-analog (D / A) circuits and other components that provide the described functions, any one or various combinations thereof. The control module may include various communication interfaces, including point-to-point or discrete lines and wired or wireless interfaces to a network, including wide area networks and local area networks, controller area network (CAN) buses, and factory-based and service-related networks including for over-the-air (OTA) software updates. The functions of the control modules set forth in this disclosure may be performed in a distributed control architecture between multiple networked control modules. Software, firmware, programs, instructions, routines, code, algorithms and similar terms mean any controller executable instruction set including calibrations, data structures and lookup tables. A control module may have a set of control routines that are executed to provide the described functionality. The routines are executed, for example, by a central processing unit and are operable to monitor inputs from sensing devices and other networked control modules and perform control and diagnostic routines to control the operation of actuators. Routines may be executed periodically during ongoing engine and vehicle operation. Alternatively, routines may be executed on demand in response to an event, the occurrence of a software call, or via a user interface input or request.

[0034] In one embodiment, the RESS 104 may include one or more electrochemical battery packs 112, such as high-capacity, high-voltage (HV) rechargeable lithium-ion battery packs, for providing power to the vehicle via the HV direct current (DC) bus 108. The RESS 104 may also include a battery manager module 114. The RESS 104 may include one or more battery packs 112 consisting of a plurality of battery pack modules, allowing flexibility of configuration and adaptation to application requirements. The battery pack may include a plurality of battery pack modules consisting of a plurality of batteries, thereby allowing flexibility of configuration and adaptation to application requirements. The battery pack module may include a plurality of batteries, thereby allowing flexibility of configuration and adaptation to application requirements. For example, in vehicle use, the RESS 104 may be modular so that the number of battery pack modules may vary to adapt to the desired energy density or range target, intended use, or cost target of a particular vehicle platform. The battery pack and battery pack modules may be configured differently and selectively according to the desired propulsion architecture and charging and discharging functions. It should be understood that the RESS 104 may be reconfigurable at any level of integration including battery packs, battery modules, and batteries. In an embodiment, the RESS may be selectively configured to provide two or more voltage levels, such as 800 volts and 400 volts, to the HV direct current (DC) bus 108 .

[0035] The motor 120 may be a multi-phase AC motor that receives multi-phase AC power via a multi-phase power bus (AC bus) 111 coupled to the power inverter 110. In one embodiment, the motor 120 is a three-phase motor and the power inverter 110 is a three-phase inverter. The power inverter 110 may include a plurality of solid-state switches in a solid-state switch portion. The power inverter 110 is coupled to a DC power source (DC input voltage (V dc )), for example, selectively at 400 or 800 volts. The voltage level of the HV DC bus 108 may be selected, established, or otherwise set by the battery manager module 114, as may be requested by the motor controller 105. The voltage level of the HV DC bus may be referred to as a DC link voltage. The motor controller 105 is coupled to the power inverter 110 to control it. The power inverter 110 is electrically connected to the stator phase windings of the three-phase stator windings of the motor 120 via the AC bus 111, wherein the current (I abc). The AC bus 111 provides a conductive connection of the multi-phase output of the power inverter 110 to the phase terminals of the stator windings. The AC bus 111 may include the AC bus characteristics of the TPIM 106, the AC bus characteristics of the motor 120, and conductors connecting the AC bus characteristics of the TPIM 106 and the AC bus characteristics of the motor 120. As used herein, the AC bus 111 includes all high voltage / high current phase conductors between the switching portion of the power inverter 110 and the motor 120, including, for example, busbars, cables, poles, etc. The power inverter 110 can be configured with suitable control circuitry, including pairs of power transistors (e.g., IGBTs) for converting the high voltage DC voltage on the HV DC bus 108 to a high voltage three-phase AC voltage (V abc ) and converts the high voltage three-phase AC voltage (V abc ) is converted into a high voltage DC voltage on the HV DC bus 108. The power inverter 110 may selectively employ any suitable pulse width modulation (PWM) scheme, such as sinusoidal pulse width modulation (SPWM) or other continuous pulse width modulation (CPWM), space vector pulse width modulation (SVPWM) or other discontinuous pulse width modulation (DPWM), including generalized discontinuous pulse width modulation (GDPWM) and adaptive (APWM), variable frequency (VFPWM), fractional duty cycle (FDPWM) pulse width modulation variants, etc., to generate the switching vector signal (S abc ) 109 to convert stored DC power from the battery pack 112 of the RESS 104 into AC power to drive the motor 120 to produce torque. The PWM scheme can be selected, established, or otherwise set by the motor controller. Similarly, the power inverter 110 can convert mechanical power delivered to the motor 120 into DC power to generate electrical energy that can be stored in the battery pack 112 of the RESS 104, including as part of a regenerative braking control strategy. The power inverter 110 can be configured to receive a switching vector signal (S) from the motor controller 105. abc ) 109 and controls the inverter state to provide motor drive and regeneration functions. Switching vector signal (S abc ) 109 may also be referred to herein as a conduction command and is understood to inherently include a power inverter switching frequency (FSW), which may be selected, established, or otherwise set by the motor controller 105. Other control signals may be provided to and from the motor controller 105, including, for example, an inverter gate drive parameter control signal 126 to select, establish, or otherwise set a slew rate, gate drive resistance, or other inverter gate drive parameters in a gate drive module 128 of the power inverter 110 for controlling the switching portion of the power inverter 110.

[0036] The control of the power inverter 110 may include high frequency switching of solid state switches according to PWM control. Many design and application considerations and limitations determine the inverter switching frequency and PWM control. Inverter control for AC motor applications may include a fixed switching frequency, such as a switching frequency of about 10-30kHz, and PWM control that minimizes switching losses of the IGBT or other power switches of the power inverter 110. Higher switching frequencies can be achieved using emerging solid state switching technologies such as silicon carbide (SiC) MOSFETs, gallium nitride (GaN) transistors, diamond MOSFETs, carbon nanotube transistors, and graphene-based transistors.

[0037] The disclosed improvements relate to a multi-phase AC motor 120 and may be implemented without limitation in HEV and EV embodiments of the electrified vehicle 100, as well as in non-vehicle applications such as power plants, hoists, mobile platforms, and robots. The motor 120 may be, for example, an interior permanent magnet (IPM) motor, a permanent magnet synchronous reluctance (PMSR) motor, a synchronous reluctance (SR) motor, an induction motor, or any AC motor including a multi-phase AC stator 120S.

[0038] The power inverter 110 operates by synthesizing a multi-phase AC voltage that is applied to the corresponding phase windings of the multi-phase stator 120S of the motor 120 through the AC bus 111. In a balanced three-phase system, the three basic AC voltages may be substantially sinusoidal and spaced 120 degrees apart. In an ideal system, the sum of the three phase voltages would be equal to zero.

[0039] In an embodiment, a plurality of motor system control parameters may be identified for controlling the motor system. The motor system may include an AC motor such as motor 120, a power inverter such as TPIM 110, and a power source such as RESS 104, such as described herein with respect to electrified vehicle 100. Non-limiting exemplary motor system control parameters may include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency for the power inverter, a gate drive parameter for the power inverter, and a direct current (DC) link voltage provided to the power inverter by the RESS. In one embodiment, at least two motor system control parameters may be used to control the motor system, and at least one of the motor system control parameters may have at least two optional settings. For example, in an embodiment, the motor system control parameters may include a PWM scheme and a switching frequency, wherein the PWM scheme includes at least two PWM settings selected from space vector pulse width modulation, generalized discontinuous pulse width modulation, fractional duty cycle pulse width modulation, or any other suitable PWM modulation scheme. The switching frequency may include two or more switching frequency settings, such as 10kHz and 20kHz. Alternative embodiments may include other groupings of exemplary motor system control parameters, including groupings of all such motor system control parameters. In embodiments where gate drive parameters of a power inverter are used as motor system control parameters, various gate drive parameters may include gate drive resistance, conversion rate, or other controllable inverter gate drive parameters. In embodiments where a direct current (DC) link voltage provided to a power inverter by the RESS is used as a motor system control parameter, various voltage settings may be selectively employed. For example, a modular, reconfigurable RESS may be selectively configured to provide different voltages to a power inverter. Advantageously, the voltage settings may be multiples of each other. For example, the RESS may include multiple modules of 400 volts, allowing the DC link voltage provided to the power inverter to be configured to 400 volts or 800 volts. Similarly, the RESS may include multiple modules of 200 volts, allowing the DC link voltage provided to the power inverter to be configured to 200 volts, 400 volts, 600 volts, or 800 volts.

[0040] Each combination of motor system control parameters and corresponding settings can be employed over the motor operating space of torque and speed to provide an associated efficiency map. Examples of such efficiency maps are described herein with respect to Figure 2A-2C as well as Figure 3A and 3B Further discussion. Figure 2A-2C as well as Figure 3A and 3BThe three axes of the 3D EQ are motor torque (TQ), motor speed (S), and motor system efficiency (E). Efficiency can be expressed, for example, by measuring the mechanical power output at the motor shaft (motor torque multiplied by motor speed) divided by the electrical power input at the inverter (DC link voltage multiplied by DC link current). Figure 2A A three-dimensional efficiency diagram corresponding to a first unique combination of motor system control parameters and corresponding settings, such as a PWM scheme with SVPWM settings and a 10kHz switching frequency, is shown. Figure 2A A solution surface (a) is shown representing a motor system efficiency solution across the operating space of motor torque and motor speed (ie, motor torque versus motor speed) during operation with a first unique combination of motor system control parameters and corresponding settings. Figure 2B A three-dimensional efficiency diagram corresponding to a second unique combination of motor system control parameters and corresponding settings, such as a PWM scheme with a GDPWM setting and a 10kHz switching frequency, is shown. Figure 2B A solution surface (b) is shown representing the motor system efficiency solution across the operating space of motor torque and motor speed (ie, motor torque versus motor speed) during operation with a second unique combination of motor system control parameters and corresponding settings. Figure 2C A three-dimensional efficiency diagram corresponding to a third unique combination of motor system control parameters and corresponding settings, such as a PWM scheme with a GDPWM setting and a 20kHz switching frequency, is shown. Figure 2C A solution surface (c) is shown representing the motor system efficiency solution across the operating space of motor torque and motor speed (ie, motor torque versus motor speed) during operation with a third unique combination of motor system control parameters and corresponding settings. Figure 2A-2C The solution surfaces (a), (b), and (c) illustrate the concepts described herein but do not represent actual efficiency data or actual combinations of motor system control parameters. Figure 2A-2C The actual motor operating space corresponding to the motor system efficiency solution visually depicted in can be derived empirically or through simulation and stored in a non-volatile memory data structure such as a reference table.

[0041] In an embodiment, the highest efficiency solution among the unique combinations of motor system control parameters can be determined for any given operating point (i.e., motor torque and motor speed combination) within the motor operating space. Thus, any suitable loss minimization function, efficiency maximization function, comparison, or arbitration operating on the solution surfaces (a), (b), and (c) data can identify the highest efficiency solution at any given operating point and the corresponding unique combination of motor system control parameters. It should be understood that while each unique combination of motor system control parameters can be associated with a corresponding efficiency solution in the corresponding solution surface, the highest efficiency solution for any given operating point can correspond to one of the unique combinations of motor system control parameters. Thus, Figure 3A Provided by FIG. 2A to FIG. 2C 3D representation of the highest efficiency solution (bounded by solid lines) within the motor operating space (i.e., torque and speed) for three exemplary unique combinations of motor system control parameters and their corresponding solution surfaces (a), (b), and (c). It should be understood that the efficiency along the efficiency axis (E) Figure 3A The view can project the regions of the highest efficiency solution surfaces (a), (b), and (c) onto Figure 3B The torque (TQ) and speed (S) planes are shown.

[0042] Figure 4A and Figure 4B An exemplary motor torque (TQ) versus motor speed (S) operating space in three dimensions and the corresponding two-dimensional efficiency solution is shown, similar to the one described herein for FIG. 2A to FIG. 2C as well as Figure 3A and Figure 3B The efficiency solution is described and illustrated. However, Figure 4A and 4B An extension of this concept to additional exemplary motor system control parameters is shown. Figure 4A and 4B In the illustrated embodiment, the motor control parameters may include a pulse width modulation scheme (PWM) for operating the power inverter, a switching frequency (FSW) of the power inverter, and a DC link voltage (VDC) provided by the RESS to the power inverter. Other embodiments may include fewer, additional, or other control parameters, such as gate drive parameters (GATE) for the power inverter. Figure 4A and Figure 4BIn the embodiment shown in , each of the exemplary motor control parameters PWM, FSW, and VDC may include two optional settings, but other embodiments may include more than two optional settings for one or more of the motor control parameters. In the illustrated embodiment, the pulse width modulation scheme PWM may have optional settings of SVPWM and GDPWM, but other embodiments may utilize other optional settings and combinations, including from non-limiting examples such as SPWM, CPWM, SVPWM, DPWM, GDPWM, APWM, VFPWM, FDPWM or other suitable pulse width modulation schemes PWM. In the illustrated embodiment, the switching frequency FSW may have an exemplary non-limiting optional setting of a lower frequency such as 10kHz and a higher frequency such as 20kHz, but other embodiments may utilize other and / or additional optional frequencies and combinations including lower and higher frequencies and intermediate frequencies. In the illustrated embodiment, the DC link voltage (VDC) may have an exemplary, non-limiting optional setting of a lower voltage such as 400 volts and a higher voltage such as 800 volts, but other embodiments may utilize other and / or additional optional voltages and combinations including lower and higher voltages and intermediate voltages. In embodiments employing gate drive parameters GATE, gate drive resistance, slew rate, or other gate drive parameters may be utilized. Gate drive resistance may have exemplary non-limiting optional settings of lower values ​​(such as 5 ohms) and higher values ​​(such as 10 ohms), but other embodiments may utilize other and / or additional optional values ​​and combinations including lower and higher values ​​and intermediate values. Gate drive slew rate may have exemplary non-limiting optional settings of lower and upper values, but other embodiments may utilize other and / or additional optional values ​​and combinations including lower and upper values ​​and intermediate values.

[0043] exist Figure 4A and Figure 4B In the present embodiment shown, certain unique combinations of exemplary motor system control parameters PWM, FSW and VDC and corresponding settings are represented by Roman numerals in Table 1 herein to mark the corresponding highest efficiency solution surface in the motor torque (TQ) versus motor speed (S) operating space. Figure 4A A three-dimensional representation of the highest efficiency solution (surface bounded by solid lines) within the motor operating space (i.e., torque and speed) from exemplary unique combinations I-VII of exemplary motor system control parameters PSW, FSW, and VDC and their corresponding settings is provided. It should be understood that the efficiency along the efficiency axis (E) Figure 4A The view can project the corresponding area of ​​the most efficient solution surface onto Figure 4B The torque (TQ) and speed (S) plane shown in FIG. A person skilled in the art will understand that Figure 4A and Figure 4BThe actual motor operating space corresponding to the motor system efficiency solution visually depicted in can be derived empirically or through simulation and stored in a non-volatile memory data structure such as a reference table.

[0044]

[0045]

[0046] Table 1

[0047] Figure 5 500 is a process flow diagram illustrating an exemplary embodiment of motor system control according to an embodiment. Process flow 500 may be repeatedly executed as part of overall electrified vehicle 100 control during ongoing vehicle operation. Process flow 600 may represent a process flow at least partially performed by a controller configured in a manner such as a controller 100. Figure 1 Routines and functions performed or implemented by one or more processors in the electrified vehicle 100, which are included in one or more of the various controllers (e.g., 103, 105, 114) and act on or in conjunction with various tangible hardware and devices including the electric propulsion system 101 described herein. A routine may represent a set of instructions stored in a non-volatile memory and executed by a processor of one or more controllers. The routines and functions of the processing flow 600 are shown in a substantially linear manner with separate tasks and groups of tasks. Those skilled in the art will understand that the described processing flow 600 may be represented in alternative manners, including, for example, state flow diagrams and activity diagrams. Those skilled in the art also understand that the various tasks in the processing flow 600 may be implemented in different orders and / or simultaneously, and may be merged or split. For purposes of illustration, the processing flow 600 may be combined with the processing flow 600 to provide a flowchart of the processing flow. Figure 1 Process flow 600 is discussed with reference to electric propulsion system 101 of exemplary electrified vehicle 100 of other figures herein. Note that aspects of process flow 600 may be performed by any suitable processing device or system, and that aspects may be implemented in whole or in part by various integrated or distributed circuits and controllers.

[0048] Process flow 500 begins at 501 and proceeds to 503 where a torque command (such as propulsion torque request 136 (T )) is received by vehicle controller 103, for example. cmd)) and the motor speed which may be derived from the angular position (θe) of the rotor shaft 125 from the position sensor 182 to determine the desired operating point. At 505, the efficiency map corresponding to the combination of motor system control parameters 512 and corresponding settings 513 (e.g., combinations I-VII of Table 1) may be referenced at the operating point, and the combination of motor system control parameters 512 and corresponding settings 513 associated with the highest efficiency may be identified, for example, by any suitable loss minimization function, efficiency maximization function, comparison, arbitration, or equivalent at 507. From 507, the identified combination of motor system control parameters and corresponding settings (i.e., combinations I-VII) may be provided to 509 for implementation of the desired operating point in motor torque and speed. Process flow 500 may return to the beginning at 501 for repeated execution.

[0049] In an embodiment, at 515, other motor system efficiency trade-off objectives may be considered and result in restrictions being imposed on combinations of motor system control parameters and corresponding settings. For example, the noise, vibration and harshness (NVH), motor bearing life, and RESS life effects of various settings of control parameters may be evaluated at 519. At certain operating points, certain combinations of motor system control parameters and corresponding settings may be undesirable. For example, at a combination of lower rotor speed, higher torque, and higher switching frequency, bearing life may be negatively affected. Therefore, under such operating conditions, higher switching frequencies may be advantageously avoided by temporarily withdrawing motor system control parameters (i.e., higher FSW settings, combinations II, IV, and VI) from control considerations. At 521, it may be decided to avoid higher switching frequencies at 517 by limiting the available corresponding settings 513 and thus limiting the available efficiency map corresponding to such a combination at 505. When it is deemed unnecessary to avoid, 521 may continue control at 509 only without such restrictions. Metrics related to noise, vibration, and harshness (NVH), motor bearing life, RESS life impact, and any other efficiency tradeoff objectives may be derived empirically or through simulation and may include objective and subjective considerations used in the impact assessment at 519 .

[0050] In an embodiment, the efficiency map can be reduced by eliminating solutions for any given combination of motor system control parameters and corresponding settings that are dominated by solutions for other combinations of motor system control parameters and corresponding settings, thereby advantageously reducing data storage resource requirements for corresponding non-volatile memory data structures (such as reference tables) and reducing processing throughput requirements of the minimization function, efficiency maximization function, comparison, arbitration, or equivalent at 507. In an embodiment, the efficiency map reduction can be achieved through a Pareto front analysis that considers a set of motor system optimization objectives in addition to motor system efficiency. In an embodiment, exemplary motor system optimization objectives can include noise, vibration and harshness (NVH), motor bearing life, and RESS life. Metrics related to noise, vibration and harshness (NVH), motor bearing life, RESS life impact, and any other motor system optimization objectives can be derived empirically or through simulation, and can include objective and subjective considerations using Pareto front analysis, and can have corresponding values ​​associated with operating points in each combination of motor system control parameters and corresponding settings in the same manner as motor efficiency. Therefore, in addition to motor system efficiency, the motor system optimization objectives of NVH, motor bearing life, and RESS life can be considered to perform Pareto front analysis. In an embodiment, the non-dominant solution of the reduced efficiency map can be evaluated at 507 by any suitable loss minimization function, efficiency maximization function, comparison, arbitration, or equivalent to identify the combination of motor system control parameters and corresponding settings (i.e., combination I-VII) to provide to 509 for implementing the desired operating point in motor torque and speed. In an alternative embodiment, the optimization function can provide an optimization score at each operating point of the non-dominant solution, wherein the optimization function considers all motor system optimization objectives (i.e., NVH, motor bearing life, and RESS life) and motor system efficiency. The optimization function may include non-equivalent weights for each motor system optimization objective and motor system efficiency. The optimization score of each non-dominant solution of the reduced efficiency map can be evaluated at 507, such as using comparison, arbitration, or equivalent to identify the highest score and the corresponding combination of motor system control parameters and corresponding settings (i.e., combination I-VII) to provide to 509 for implementing the desired operating point in motor torque and speed.

[0051] At 505, an efficiency graph corresponding to a combination of motor system control parameters 512 and corresponding settings 513 (e.g., combinations I-VII of Table 1) can be referenced at an operating point and the combination of motor system control parameters 512 and corresponding settings 513 associated with the highest efficiency can be identified, for example, by any suitable loss minimization function, efficiency maximization function, comparison, arbitration, or equivalent at 507.

[0052] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to also include the plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0053] All numerical values ​​herein are assumed to be modified by the term "about", whether explicitly stated or not. For the purposes of this disclosure, ranges may be expressed as from "about" one particular value to "about" another particular value. The term "about" generally refers to a range of values ​​that one skilled in the art would consider equivalent to the stated value, having the same function or result, or generally being reasonably within the manufacturing tolerance of the stated value. Similarly, the numerical values ​​set forth herein are provided as non-limiting examples and may be nominal values, it being understood that actual values ​​may differ from the nominal values ​​depending on the environment, design and manufacturing tolerances, age, and other factors.

[0054] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly on" another element, there are no intervening elements. Therefore, unless explicitly described as "directly," when describing a relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship between the first element and the second element without other intervening elements, but can also be an indirect relationship between the first element and the second element with one or more intervening elements (either spatially or functionally) present.

[0055] One or more steps within the method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure may be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the permutation of one or more embodiments with respect to each other is still within the scope of the present disclosure.

[0056] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0057] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0058] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A method of controlling a motor system, the motor system comprising a rechargeable energy storage system (RESS), an alternating current (AC) motor, and a power inverter between the rechargeable energy storage system and the AC motor, the method comprising: providing a plurality of efficiency maps for control usage consideration, each efficiency map corresponding to a respective predetermined combination of at least two motor system control parameters and associating a motor operating space in motor torque and motor speed with a corresponding motor system efficiency solution, wherein at least one of the at least two motor system control parameters includes at least two respective selectable settings; receiving a motor speed signal; receiving a motor torque command; determining from the plurality of efficiency maps respective predetermined combinations of the at least two motor system control parameters associated with a highest motor system efficiency solution at a motor operating point corresponding to the motor speed signal and the motor torque command; and The motor is controlled based on respective predetermined combinations of the at least two motor system control parameters.

2. The method according to claim 1, wherein: The motor system control parameters include a pulse width modulation (PWM) scheme for operating the power inverter, a switching frequency for the power inverter, gate drive parameters for the power inverter, and a direct current (DC) link voltage provided by the RESS to the power inverter.

3. The method according to claim 2, wherein: The pulse width modulation (PWM) scheme includes a first corresponding selectable setting which is a space vector pulse width modulation and a second corresponding selectable setting which is one of a generalized discontinuous pulse width modulation and a fractional duty cycle pulse width modulation.

4. The method according to claim 2, wherein: The switching frequency includes a first corresponding selectable setting and a second corresponding selectable setting, the first corresponding selectable setting is a first frequency, the second corresponding selectable setting is a second frequency, wherein the second frequency is a multiple of the first frequency.

5. The method of claim 2, wherein the gate drive parameter comprises a first corresponding selectable setting and a second corresponding selectable setting, the first corresponding selectable setting being a first gate resistance, the second corresponding selectable setting being a second gate resistance, wherein the second gate resistance is greater than the first gate resistance. 6 . The method of claim 2 , wherein the DC link voltage includes a first corresponding selectable setting as a first voltage and a second corresponding selectable setting as a second voltage, wherein the second voltage is a multiple of the first voltage.

7. The method according to claim 1, wherein: Each efficiency map is reduced by eliminating the corresponding motor system efficiency solutions in the motor operating space of motor torque and motor speed that are dominated by the motor system efficiency solutions in the motor operating space of motor torque and motor speed of other efficiency maps using Pareto front analysis that takes into account a set of motor system optimization objectives.

8. The method according to claim 7, wherein: The set of motor system optimization objectives includes a first metric of noise, vibration, and harshness, a second metric of motor bearing life, and a third metric of RESS life.

9. The method according to claim 1, wherein: At least one of the plurality of efficiency maps is withdrawn from control consideration based on a determined unacceptable impact on at least one of a set of motor system efficiency trade-off objectives at the motor operating point.

10. The method according to claim 9, wherein: The set of motor system efficiency tradeoff objectives includes a first metric of noise, vibration, and harshness, a second metric of motor bearing life, and a third metric of RESS life.

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