Closed-loop control for transient operation of variable flux and permanent magnet motors

Abstract

A method for controlling transient operation of a rotating electric machine in an electric powertrain or other electric system includes determining an estimated output torque of the electric machine using a d-axis current command and a q-axis current command and an additional value (i.e., an actual shunt angle or machine temperature) via a torque estimation block during a shunt angle transition that occurs during a maximum torque per ampere (MTPA) control region. The method includes subtracting the estimated output torque from the commanded output torque to derive an adjusted commanded torque value or torque error; and calculating a Δd-axis current command and a Δq-axis current command from the torque error. The method includes adjusting the d-axis current command and the q-axis current command using a Δ command to produce adjusted d-axis current command and q-axis current command, which are then used by the torque estimation block as closed-loop feedback control terms.

Description

Technical Field

[0001] The invention relates to a method for controlling transient operation of a rotating electrical machine and to an electric powertrain. Background Art

[0002] introduction

[0003] Rotating electrical machines are used to provide torque in a wide variety of electromechanical systems. In a typical radial flux machine, for example, a cylindrical rotor is surrounded by a cylindrical stator having a set of stator field windings. The rotor and an integrally connected rotor shaft rotate in unison when the stator field windings are energized in sequence by a high voltage power supply, typically in the form of a power inverter module and a multi-core battery pack. The torque generated by the machine's rotation is then transferred to the connected load to perform work such as generating electricity, cranking and starting an internal combustion engine, or powering road wheels, propeller blades, or other driven loads depending on the application.

[0004] In a permanent magnet (PM) machine, solid permanent magnets are surface mounted or embedded in each iron lamination of the rotor. The permanent magnets are arranged to form alternating magnetic north and south poles around the circumference of the rotor. The rotating stator magnetic field interacts with the strong magnetic field of the permanent magnets to rotate the rotor shaft. The input voltage delivered to each stator winding by external control ultimately controls the speed and torque produced by the PM motor. The energized PM motor generates a back electromotive force (back EMF) as a voltage opposite to the voltage of the energized stator winding. Therefore, field weakening techniques are often used to control PM motor operation, which reduces the back EMF of the motor at higher speeds. In contrast to PM motors, variable flux motors (VFMs) abandon the use of the above-mentioned permanent magnets. VFMs are able to provide relatively high output torque while operating with high energy efficiency, while PM motors tend to experience higher energy losses under high speed / low load operating conditions.

[0005] Magnetic flux can be varied within the flux path of a rotating electric machine to change the back EMF of the motor, such as by using machine demagnetization or magnetization, mechanical flux shunting elements, or the field weakening techniques described above. For example, a typical VFM may vary the position or angle (shunting angle) of a hardware device embedded within the motor to impart a purposeful change in direction in the magnetic flux passing through the field circuit or shunting field. Field weakening techniques in a VFM or PM motor have the net effect of reducing the stator field current and back EMF of the motor. Summary of the invention

[0006] Control strategies, control systems, and associated control logic for controlling the transient response of rotating electrical machines are disclosed herein. In particular, the present disclosure provides a closed-loop / feedback-based control solution for the purpose of improving the overall speed and accuracy of torque transient response in variable flux machines (VFMs), and the teachings of the present invention may also be extended to real-time control and thermal regulation of permanent magnet (PM) machines using a simple temperature-based alternative approach as described herein.

[0007] As will be appreciated by one of ordinary skill in the art, a computer controlled system (such as a rotating electric machine of the type treated herein) will exhibit periods of steady-state and transient operation over the course of ongoing operation. For example, the output torque produced by an electric traction motor (when supplied with a constant voltage at a constant operating temperature) will eventually stabilize into a relatively predictable steady-state torque. Thus, for a particular motor used in a given application, steady-state performance is typically available in the form of a calibrated torque-speed curve. An associated motor control processor, staged controller, and associated control logic may rely on the steady-state torque response of the motor in order to provide power to a driven load in a predictable and repeatable manner.

[0008] In contrast to the steady-state torque response, the transient torque response of an electric machine is the time-varying response of the machine to one or more changing input conditions before or after steady-state operation. Relatively slow and / or large torque transients can exacerbate noise, vibration, and harshness ("NVH") effects. For example, in a motor vehicle having an electric powertrain driven by an electric traction motor, an overly abrupt torque transient response may be perceived by the operator of the motor vehicle as a torque disturbance, and as a result as reduced drive quality. Therefore, the present control strategy seeks to optimize the speed and accuracy of the torque transient response of a rotating electric machine (including VFM and PM machines), with the proposed solution and associated hardware being directed to this end.

[0009] In an exemplary embodiment, a method for controlling transient operation of a rotating electric machine includes: determining an estimated output torque of the electric machine during a shunt angle transition occurring during an MTPA control region of the electric machine, wherein the transition modifies the flux path within the electric machine and the back EMF of the electric machine. The process steps are performed by a torque estimation block of a controller using a d-axis current command, a q-axis current command, and an additional value. The additional value is the actual shunt angle or temperature of the electric machine depending on the configuration of the electric machine, as described below. The method includes: subtracting the estimated output torque from the commanded output torque, thereby deriving an adjusted commanded torque value or torque error; and calculating a Δd-axis current command and a Δq-axis current command using the adjusted commanded torque value or torque error.

[0010] Additionally, the method in this embodiment includes: adjusting the d-axis current command and the q-axis current command of the motor using the Δd-axis current command and the Δq-axis current command respectively via the controller. Finally, the controller provides the d-axis command and the q-axis command as closed-loop feedback control terms to the torque estimation block.

[0011] The rotating electrical machine may optionally be embodied as a variable flux machine, in which case the additional value is the actual shunt angle mentioned above. When the electrical machine is a permanent magnet machine, the additional value is the temperature of the electrical machine.

[0012] The method may include: feeding the DC bus voltage, torque conversion command and speed of the motor into separate d-axis command lookup tables and q-axis command lookup tables of the controller; and adding a Δd-axis current command and a Δq-axis current command to the respective outputs of the separate d-axis command lookup tables and the q-axis command lookup tables, thereby deriving the d-axis current command and the q-axis current command.

[0013] Calculating the Δd-axis current command and the Δq-axis current command may include: processing the torque value or torque error of the adjusted command through a proportional-integral (PI) regulator to generate a Δ steady-state current amplitude; adding the Δ steady-state current amplitude to the steady-state current amplitude to generate a new steady-state current value; processing the new steady-state current value through an MTPA β angle lookup table to generate a current command β angle of the motor; and using a transformation block of the controller to transform the current command β angle into adjusted d-axis values ​​and q-axis values.

[0014] The method may include selectively and automatically resetting the PI regulator in response to a predetermined condition.

[0015] During a field weakening control region of the electric machine occurring before or after the MTPA control region, the method may include adjusting a d-axis current command using a modulation index control loop of the controller and thereafter adjusting a q-axis current command via a torque control loop of the controller.

[0016] A calibrated torque hysteresis may be implemented by the controller to avoid oscillations or jitters between the MTPA control region and the field weakening control region.

[0017] Determining the estimated output torque may include using a flux lookup table to determine the corresponding d-axis flux contribution and q-axis flux contribution. In such an embodiment, the torque estimation block includes a lookup table indexed by d-axis current, q-axis current, d-axis flux contribution, and q-axis flux contribution.

[0018] Also disclosed herein is an electric powertrain having: a rotating electric machine having phase windings; a traction power inverter module (TPIM) connected to the rotating electric machine via the phase windings; and an automatic control system or controller. In a possible embodiment, the controller has a current control block connected to the TPIM, the current control block being configured to: receive a d-axis current command and a q-axis current command; and in response to the d-axis current command and the q-axis current command, output a d-axis voltage command and a q-axis voltage command to the TPIM. The controller also includes a shunt control block, the shunt control block being configured to: transform an actual shunt angle of the electric machine during an MTPA control region of the electric machine, thereby modifying a magnetic flux path within the electric machine and the back EMF of the electric machine.

[0019] In this embodiment, the controller is configured to: execute instructions to thereby control transient operation of the rotating electric machine, which causes the control system to determine an estimated output torque of the rotating electric machine via a torque estimation block using a d-axis current command, a q-axis current command, and an additional value during a shunt angle transition. As described above, the additional value may be an actual shunt angle of the electric machine when the electric machine is a variable flux electric machine, or a temperature of the electric machine when the electric machine is a permanent magnet electric machine.

[0020] The controller is configured to: subtract the estimated output torque from the commanded output torque, thereby deriving an adjusted commanded torque value or torque error; and calculate a Δd-axis current command and a Δq-axis current command from the adjusted commanded torque value or torque error. The controller also uses the Δd-axis command and the Δq-axis command to adjust the actual d-axis current command and the actual q-axis current command of the motor, respectively, thereby generating a d-axis command and a d-axis command. The controller then provides the d-axis command and the q-axis command as closed-loop feedback control terms to the torque estimation block.

[0021] The above and other features and advantages of the present disclosure will become apparent from the following detailed description of the embodiments and the best mode for carrying out the disclosure when taken in conjunction with the accompanying drawings and the appended claims.

[0022] The present invention provides the following technical solutions:

[0023] 1. A method for controlling transient operation of a rotating electrical machine, the method comprising:

[0024] During a shunt angle transition occurring during a maximum torque per ampere (MTPA) control region of the motor, wherein the transition modifies a magnetic flux path within the motor and a back EMF of the motor:

[0025] determining an estimated output torque of the electric machine via a torque estimation block within a torque loop of a controller using a d-axis current command, a q-axis current command, and an additional value, wherein the additional value is an actual shunt angle of the electric machine or a temperature of the electric machine;

[0026] subtracting the estimated output torque from the commanded output torque to thereby derive an adjusted commanded torque value or torque error;

[0027] Calculating a Δd-axis current command and a Δq-axis current command using the adjusted commanded torque value or torque error;

[0028] adjusting a d-axis current command and a q-axis current command of the motor using the Δd-axis current command and the Δq-axis current command, respectively, via the controller; and

[0029] The d-axis current command and the q-axis current command are provided to the torque estimation block as closed-loop feedback control terms.

[0030] 2. The method according to technical solution 1, wherein the rotating electrical machine is a variable flux electrical machine, and wherein the additional value is the actual shunt angle.

[0031] 3. The method according to technical solution 1, wherein the motor is a permanent magnet motor, and wherein the additional value is the temperature of the motor.

[0032] 4. The method according to technical solution 1 further comprises:

[0033] feeding the DC bus voltage, torque conversion command and speed of the motor into separate d-axis current command lookup tables and q-axis current command lookup tables of the controller; and

[0034] The Δd-axis current command and the Δq-axis current command are added to respective outputs of the separate d-axis current command lookup table and q-axis current command lookup table, thereby deriving the d-axis current command and the q-axis current command.

[0035] 5. The method according to technical solution 1, wherein calculating the Δd-axis current command and the Δq-axis current command includes: processing the torque value or torque error of the adjusted command through a proportional-integral (PI) regulator to generate a Δ steady-state current amplitude; adding the Δ steady-state current amplitude to the steady-state current amplitude to generate a new steady-state current value; processing the new steady-state current value through an MTPA β angle lookup table to generate a current command β angle of the motor; and using the transformation block of the controller to transform the current command β angle into adjusted d-axis value and q-axis value.

[0036] 6. The method according to technical solution 5 further includes: selectively and automatically resetting the PI regulator in response to predetermined conditions.

[0037] 7. The method according to technical solution 1 further comprises:

[0038] During a field weakening control region of the electric machine occurring before or after the MTPA control region:

[0039] regulating the d-axis current command using a modulation index control loop of the controller; and

[0040] The q-axis current command is regulated via the torque control loop of the controller.

[0041] 8. The method according to technical solution 7 further comprises:

[0042] A calibrated torque hysteresis is used to avoid oscillations or jitters between the MTPA control region and the field weakening control region.

[0043] 9. A method according to technical solution 1, wherein determining the estimated output torque includes using a flux lookup table to determine the d-axis flux contribution and the q-axis flux contribution, and wherein the torque estimation block includes a lookup table indexed by the d-axis current command, the q-axis current command, the d-axis flux contribution and the q-axis flux contribution.

[0044] 10. An electric powertrain, comprising:

[0045] a rotating electrical machine having phase windings;

[0046] a traction power inverter module (TPIM) connected to the rotating electric machine via the phase windings; and

[0047] A controller having:

[0048] a current control block connected to the TPIM, the current control block being configured to: receive a d-axis current command and a q-axis current command; and output a d-axis voltage command and a q-axis voltage command to the TPIM in response to the d-axis current command and the q-axis current command; and

[0049] a shunt control block configured to: shift an actual shunt angle of the motor during a maximum torque per ampere (MTPA) control region of the motor, thereby modifying a magnetic flux path within the motor and a back EMF of the motor;

[0050] The controller is configured to: execute instructions to control transient operation of the rotating electrical machine, and the execution of the instructions causes the control system to:

[0051] determining an estimated output torque of the rotating electric machine using a d-axis current command, a q-axis current command, and an additional value via a torque estimation block, wherein the additional value is an actual shunt angle of the electric machine or a temperature of the electric machine;

[0052] subtracting the estimated output torque from the commanded output torque to thereby derive an adjusted commanded torque value or torque error;

[0053] calculating a Δd-axis current command and a Δq-axis current command from the adjusted commanded torque value or torque error;

[0054] adjusting an actual d-axis current command and an actual q-axis current command of the motor using the Δd-axis current command and the Δq-axis current command, respectively, thereby generating the d-axis command and the d-axis command; and

[0055] The d-axis current command and the q-axis current command are provided to the torque estimation block as closed-loop feedback control terms.

[0056] 11. An electric powertrain according to technical solution 10, wherein the rotating electrical machine is a variable flux electrical machine, and wherein the additional value is the actual shunt angle.

[0057] 12. An electric powertrain according to technical solution 10, wherein the motor is a permanent magnet motor, and wherein the additional value is the temperature of the motor.

[0058] 13. The electric powertrain according to technical solution 10, wherein the controller is configured to:

[0059] feeding the DC bus voltage, torque conversion command and speed of the motor into separate d-axis current command lookup tables and q-axis current command lookup tables; and

[0060] The Δd-axis current command and the Δq-axis current command are added to respective outputs of the d-axis current command lookup table and the q-axis current command lookup table, thereby deriving the d-axis current command and the q-axis current command.

[0061] 14. The electric powertrain according to technical solution 10, wherein the controller is configured to:

[0062] calculating the Δd-axis current command and the Δq-axis current command by processing the adjusted commanded torque value through a proportional-integral (PI) regulator, thereby generating a Δ steady-state current magnitude;

[0063] adding the Δ steady-state current amplitude to the steady-state current amplitude to generate a new steady-state current value;

[0064] Processing the new steady-state current value through the MTPA β angle lookup table to generate a current command β angle for the motor; and

[0065] The current command β angle is transformed into adjusted d-axis and q-axis values ​​using a transformation block of the controller.

[0066] 15. An electric powertrain according to technical solution 14, wherein the controller is configured to selectively and automatically reset the PI regulator in response to predetermined conditions.

[0067] 16. The electric powertrain according to claim 14, wherein the controller is configured to: during a field weakening control region of the rotating electrical machine that occurs before or after the MTPA control region:

[0068] regulating the d-axis current command using a modulation index control loop or a voltage control loop of the controller; and

[0069] The q-axis current command is regulated via the torque control loop of the controller.

[0070] 17. An electric powertrain according to technical solution 16, wherein the controller is configured to use a calibrated torque hysteresis to avoid oscillations between the MTPA control region and the magnetic field weakening control region.

[0071] 18. An electric powertrain according to technical solution 14, wherein the controller is configured to determine the estimated output torque of the motor by determining the d-axis flux contribution and the q-axis flux contribution using a flux lookup table, and wherein the torque estimation block includes a lookup table indexed by the d-axis current command, the q-axis current command, the d-axis flux contribution and the q-axis flux contribution.

[0072] 19. The electric powertrain according to Technical Solution 14 further comprises: a driven load connected to the rotating electric machine.

[0073] 20. An electric powertrain according to technical solution 19, wherein the drive load includes one or more road wheels of a motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 is a schematic illustration of a motor vehicle having an electric powertrain with a rotating electric machine and a closed-loop / feedback control system constructed as set forth herein.

[0075] Figure 2 is a schematic logic diagram of transient torque control of an exemplary variable flux motor (VFM) when operating in a maximum torque per ampere (MTPA) control region.

[0076] Figure 3is a schematic logic diagram of transient torque control of an exemplary VFM when operating in the field weakening control region.

[0077] Figure 4 yes Figure 2 A modified embodiment of the schematic logic diagram shown in provides optional thermal adaptation for a permanent magnet (PM) machine operating in an MTPA control region.

[0078] Figure 5 and Figure 6 Schematic diagram of the optional enable condition and integrator reset logic, respectively, both of which can be used in the MTPA control area.

[0079] The present disclosure is susceptible to various modifications and alternative forms, and some representative embodiments have been shown in the drawings by way of example and will be described in detail herein. However, it should be understood that the novel aspects of the present disclosure are not limited to the specific forms illustrated in the drawings. On the contrary, the present disclosure will cover modifications, equivalents, combinations and alternatives that fall within the scope and spirit of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION

[0080] The present disclosure allows for embodiments in many different forms. Representative examples of the present disclosure are shown in the drawings and described in detail herein, and it should be understood that the described embodiments are provided as examples of the disclosed principles, rather than limitations on the broad aspects of the present disclosure. For that purpose, elements and limitations described in the abstract, introduction, summary, and detailed description but not explicitly set forth in the claims should not be incorporated into the claims individually or collectively by implication, inference, or otherwise.

[0081] For the purposes of this description, unless expressly disclaimed, the use of the singular includes the plural, and vice versa, the terms "and" and "or" shall both be conjunctive and disjunctive, "any" and "all" shall both mean "any and all", and the words "include", "comprising", "including", "having", etc. shall mean "including but not limited to". In addition, approximate words such as "about", "almost", "substantially", "generally", "approximately", etc. may be used herein in the sense of "is, is approximately, or is nearly...", or "within 0-5% of...", or "within an acceptable manufacturing tolerance", or their logical combinations.

[0082] Referring to the drawings, wherein like reference numerals refer to like parts, Figure 1A motor vehicle 10 is schematically depicted having a body 11, an electric powertrain 12, and one or more road wheels 13 in rolling contact with a road surface 15. Although omitted for simplicity of illustration, the electric powertrain 12 also includes an onboard power source, such as a high-voltage direct current (DC) battery pack having a number of high-energy rechargeable battery cells suitable for the application, such as lithium-ion battery cells or cells constructed from another suitable battery chemistry.

[0083] This type of battery pack is discharged in a controlled manner to enable the rotating electric machine (M E ) 14, which in turn may be embodied as a variable flux motor (VFM) or a permanent magnet (PM) machine according to the representative embodiments described herein. The electric machine 14 may optionally be configured as an electric traction motor for use as a primary torque source in the electric powertrain 12 (wherein the electric machine 14 in this configuration is operable to generate motor torque (arrow T) at a level sufficient to propel the motor vehicle 10). M )) or a generator configured to recharge the above-mentioned battery pack.

[0084] The motor vehicle 10 may also include additional torque sources not specifically described herein, such as an internal combustion engine and / or an additional electric machine 14, and thus Figure 1 The representative embodiments are intended to illustrate the present teachings and are not limiting. The beneficial applications of the motor 14 are generally not limited to mobile applications, nor are they specifically limited to vehicle propulsion applications. A person of ordinary skill in the art will appreciate that when using the following reference Figures 2 to 6 When controlled by the described strategy, the incidental benefits of the disclosed electric machine 14 can be extended to rely on the use of motor torque (arrow T M ) for stationary and mobile applications, such as ships, aircraft, rail vehicles, mobile platforms, robots, power plants, washing machines or other appliances, or other fixed or mobile systems.

[0085] As a basis for this solution, it should be recognized in this paper that Figure 1The motor 14 includes a rotor 14R and a stator 14S, generally of the type described above, arranged concentrically. A magnetic circuit exists between the laminations of the rotor 14R and the stator 14S, across a small air gap between the rotor and the stator, and possibly across a small air pocket defined by the rotor. The flux path within this magnetic circuit is varied in certain configurations of the motor 14 (e.g., the VFM described above), such as, but not limited to, by selectively shunting the flux at specific operating points in a targeted manner (such as, by moving or skewing a phasing mechanism or other shunting element, for example, as described in U.S. Pat. Nos. 8,562,471 B2 to Savagian et al., 9,077,227 B2 to Theobald et al., and 10,541,578 B2 to Swales et al., which are incorporated herein by reference in their respective entireties) or other suitable shunting methods. As will be appreciated by one of ordinary skill in the art, passively or actively controlled skewing is used to increase or decrease the torque capacity of the motor. Thus, in some types of electric machines, including the present electric machine 14, the commanded shunt angle is a specific control variable upon which an associated motor control unit relies, and where such control unit Figure 1 Schematically shown as controller (C) 50.

[0086] In the illustrated embodiment, the electric powertrain 12 includes a traction power inverter module (TPIM) 16 that is electrically connected to the battery pack (not shown) described above. The ON / OFF conduction state of internal semiconductor switches (not shown) within the TPIM 16 is automatically controlled via a PWM controller 28 via pulse width modulation (PWM) or other modulation techniques to generate an alternating current output voltage (VAC) at a level suitable for energizing the electric machine 14.

[0087] Figure 1 The controller 50 can be used to respond to the input signal (arrow CC I ) to regulate the ongoing transient and steady-state operation of the motor 14, wherein the controller 50 is via the control signal (arrow CC O ) is transmitted to the motor 14 and / or its associated logic blocks to do so, as described herein and Figure 2-6 For example, the controller 50 may monitor the speed and torque of the motor 14 using sensors (not shown), modeling, and / or calculations, and may selectively transition from a maximum torque per ampere (MTPA) mode to a flux weakening control mode at certain torque-speed operating points or when otherwise desired.

[0088] References in this article Figure 2-4The controller 50 described by the associated logic blocks may be physically implemented as one or more electronic control units or computer nodes, each having the necessary memory (M) and processor (P), as well as other associated hardware and software, such as clocks or timers, input / output circuits, buffer circuits, etc. The memory (M) may include a sufficient amount of read-only memory, such as magnetic or optical memory. Instructions for implementing the control method may be programmed into the memory (M) as computer-readable instructions 100 and executed by the processor (P) during operation of the vehicle 10, thereby optimizing operational efficiency. For simplicity, the term "controller" is used herein and includes control modules, units, processors and arrangements thereof, including logic circuits, application-specific integrated circuits (ASICs), electronic circuits, central processing units, microprocessors, and other hardware as needed to provide the programming functions described below.

[0089] Still reference Figure 1 As described above, the core hardware and programmed memory elements of the controller 50 are used to control the steady-state operation of the motor 14 and to regulate the operation of the motor 14 during transient response. For example, the optional VFM embodiment of the motor 14 may be used during steady-state operation. Figure 1 The schematic diagram of the control logic. As the input signal (arrow CC I ), for example, the controller 50 may receive the motor control input 20 (shown as a motor torque conversion command ), where slew rate is defined herein as the rate of change of the command per unit time of the torque command. The motor control inputs 20 also include the current DC bus voltage (V DC ), and the measured or actual / reported speed of the rotor 14R |N RPM |.

[0090] The motor control input 20 is fed into calibrated lookup tables 22 (i.e., lookup tables 22A, 22B, and 22C), each of which is programmed into or accessible by the controller 50 and indexed by torque conversion command, speed, and DC bus voltage. In the illustrated embodiment, the lookup table 22A provides the corresponding shunt angle command f * s h unt ), the lookup table 22B provides the corresponding direct axis (d axis) current command (I d * ), and the lookup table 22C provides the corresponding orthogonal axis (q-axis) command (I q * ).

[0091] Still reference Figure 1The output values ​​from the lookup tables 22B and 22C are added to the corresponding d-axis feedback control term and q-axis feedback control term (referred to herein as Δ current command value and (where an asterisk superscript (*) indicates a command value), which in turn is Figure 2-4 Such a value may be rate limited to within a calibrated allowable maximum / minimum slew rate using corresponding limit blocks 24 (“LIMIT”) (e.g., limit blocks 24A, 24B, and 24C). The corrected and slew rate limited d-axis current command is then and q-axis current command The current control block 26 (“current control”) (commonly known as “current controller”) is configured to calculate the corresponding d-axis voltage command and q-axis voltage command

[0092] Thereafter, the d-axis voltage command output by the current control block 26 is used by the controller 50 in the modulation process. and q-axis voltage command For example, by feeding the d-axis voltage command and the q-axis voltage command into the PWM control block 28, which in turn outputs a, b and c phase switching commands (Da, Db, Dc) to the TPIM 16. In response, the TPIM 16 controls the ON / OFF state of the semiconductor switches contained therein, and as will be appreciated by those of ordinary skill in the art, the TPIM thereafter outputs a multi-phase voltage (VAC) to the motor 14, thereby powering the connected drive load (such as, the road wheels 13).

[0093] exist Figure 1 In the exemplary steady-state control logic depicted in FIG. 1 , the slew rate limited shunt position command from the limiting block 24A may be fed into a messaging block (“MSG”) 28. For example, the controller 50 may receive and transmit messages on the motor vehicle 10 using a controller area network (CAN) or another message-based protocol. Thus, the messaging block 28 is configured to convert the CAN message into an appropriate transmission control command as needed. The corresponding control signal is then provided to a shunt control block (“shunt controller”) 30, i.e., a logic block and associated hardware configured to adjust the shunt angle of a shunt element or mechanism used within the motor 14. The shunt control block 30 is also configured to measure and report the actual shunt position (f ) using, for example, an angular encoder or other suitable position sensor. shunt). The actual shunt position is relayed to the rotating electric machine 14, e.g., to a motor control processor or MCP resident within the electric machine 14, via a communications relay block 32, e.g., as a CAN message ("CAN message to MCP"). As will be appreciated, the shunt control block 30 may be located within the same control unit as the rest of the logic, in which case the CAN messaging described above is not required.

[0094] refer to Figure 2 Schematically depicted control logic 50L, when the motor 14 is embodied as a VFM, the control logic can be used to control the torque transient response of the rotating motor 14. In this embodiment, the control logic 50L is used to control the motor 14 during operation in the maximum torque per ampere (MTPA) control region. As will be appreciated by those skilled in the art, Figure 1 The resistive losses in the stator 14S of the motor 14 shown in FIG. 1 depend on the magnitude of the phase current fed into each stator winding. Therefore, the operation in the MTPA control region seeks to make the output torque (arrow T) of the motor 14 at a given current magnitude. M ) is maximized. As the shunt angle changes, the back EMF in the motor 14 will also change, which in turn causes a change in the output torque ( Figure 1 Arrow T M ). Figure 2 The control logic 50L when used in the MTPA control region may therefore help speed up the overall transient response time and smooth out possible torque disturbances.

[0095] like Figure 2 As shown in FIG. 1 , the control logic 50L includes a torque estimation block 40 (“Torque Estimation”) configured to: use the feedback current command I d *fd and I q *fd (these feedback current commands are Figure 2 The actual d-axis current command and q-axis current command shown on the right side of the figure) and the actual shunt angle (f shunt ), to determine the estimated torque (T est ). Finally, the controller 50 is based on the actual shunt angle f shunt and the commanded shunt angle f * shunt To adjust the d-axis / q-axis current commands to the motor 14.

[0096] In particular, the controller 50 is configured to receive or otherwise determine the commanded flow angle (f * shunt ), and the commanded shunt angle (f) is processed by a calibrated flux lookup table 34 (“flux command lookup”) *shunt ). Such a table 34 allows the controller 50 to determine the corresponding d-axis flux contributions and the q-axis flux contribution Flux contribution of command and Together with the d-axis current command and q-axis current command are fed together into the torque command calculation block 35 ("Torque Command Calculation"). Then, from the commanded torque (arrow T * ) minus the estimated torque value (T est ) and passes it to the Proportional Integral (PI) regulator block.

[0097] In a possible embodiment, another lookup table 39 (“flux actual lookup table”) can be used to calculate the actual shunt position (f shunt ) and the corresponding q-axis and d-axis feedback (fd) control terms / values ​​(i.e., i d *fd and i q *fd), the q-axis and d-axis feedback (fd) control terms / values ​​correspond to the following description and Figure 2 The output from the lookup table 39 is the actual d-axis flux contribution and q-axis flux contribution (φ d ,φ q ), which may be fed into the torque estimation block 40 and thereby used to determine the estimated torque (T est ), for example by extracting the estimated torque from a lookup table. In other embodiments, the torque estimation block 40 may use a calibration equation to derive the estimated torque, and thus the use of a lookup table for this purpose is merely exemplary.

[0098] Still reference Figure 2 , the steady-state current value (ΔL) output from the PI regulator ss ) and adds it as an adjustment value to the q-axis current and d-axis current (I d * and I q * ) (or i d * fd and i q * fd), from which the error-corrected steady-state current (I SS New). Then, the steady-state current (I SS New) is used by the MTPA current command angle lookup table 36 ("MTPA β angle lookup") to provide a corresponding current command angle (β) so that I SSThe command is decoupled into a d-axis current command and a q-axis current command. The transformation block 37 of the controller 50 receives the β angle and the error-corrected steady-state current (I SS New) and use them to output the adjusted d-axis current command and q-axis current command / torque error (i.e., I d_adj * , and I q_adj * ), the adjusted d-axis current command and q-axis current command / torque error are further used to modify the actual d-axis current command and q-axis current command, i.e., I d * and I q * Then, the error compensation value ΔI d and ΔI q is passed to the limiter block 24 (“Limiter”) to derive the corresponding delta command ΔI d * and ΔI q *, the Δ command and the output of the lookup table 22B (I d * ) and 22C output (I q * ) are added and then fed to Figure 1 There, these values ​​are used to calculate the final / actual d-axis current command and q-axis current command I d * and I q * The final / actual d-axis current command and q-axis current command are ultimately used by the controller 50 to regulate the operation of the electric machine 14 in the MTPA control region.

[0099] Control strategy (whose process is in Figure 2 ) is tailored for use with a VFM embodiment of the motor 14, as described above. However, with a few simple adjustments, the control logic 50L can be easily expanded for use in a PM motor. Figure 4 An example of this approach is shown in . Figure 4 ,for Figure 2 The shunt position values ​​(f * shunt and f shunt ), one may replace the temperature value, such as the commanded and actual magnet temperature values ​​(Temp * and Temp_act). Figure 2 and Figure 4 The temperature is otherwise identical in both structure and operation.The actual temperature may be estimated or measured.

[0100] Using the VFM example, when the shunt angle changes, the motor back EMF will also change, and the corresponding motor torque will be adjusted based on the actual shunt angle. The proposed control method can adjust the current command so that the generated torque is maintained even if the actual shunt angle is changing. For PM motors, when the motor temperature changes, the motor back EMF will also change, and under the same current command conditions, the corresponding motor torque will also change. Figure 4 The proposed control scheme will maintain the motor output torque regardless of changes in motor temperature. In this way, the method adapts to thermal changes in the PM motor.

[0101] In the exemplary VFM embodiment of the electric machine 14, the MTPA control Figure 2 The control logic 50L can also be easily extended to the field weakening control area for the same VFM. Figure 3 As shown in , for example, a modulation index loop / voltage control loop 150L separate from the torque control loop 150T can be used for this purpose. As will be appreciated by those of ordinary skill in the art, the calculation block 42 and the proportional integral regulator block (PI) can be used to derive the d-axis feedback adjustment / Δ current described above, i.e.,

[0102] For example, the control loop 150L may be used to calculate the adjusted modulation index command (ΔMI) as shown in FIG. * ), and the adjusted modulation index command (ΔMI * ) is fed into block 42. As understood in the art and used herein, the modulation index is the ratio of the terminal voltage command to the motor 14 divided by the commanded voltage (six-step voltage). Block 42 feeds Figure 1 The current DC bus voltage of the TPIM16 is divided by the current current speed (i.e., Vdc / ω e ), from which the d-axis Δ current is derived This approach enables transient torque control to occur in the flux weakening control region. Dual loop control is utilized in the field weakening control region, where the modulation index loop 150L is used to regulate the d-axis current and where the torque control loop (i.e., Figure 3 Everything outside the loop 150L in () is used to regulate the q-axis current.

[0103] refer to Figure 5 and Figure 6 , when used in two ways, can improve transient torque control in the MTPA region, as described above in reference Figure 2 As described. Figure 5In the graph 60 of the control regions in FIG. 6A , a torque hysteresis 63 may be implemented between the MTPA control region 62 and the field weakening control region 64. This approach may help avoid oscillations or jitters between the MTPA control region and the field weakening control region and the associated strategies. The conditions for exactly when to enter or exit the MTPA control region may be based on the current torque command relative to a calibrated threshold. As shown in FIG. Figure 6 As shown in the exemplary anti-windup logic 70, for example, it would be beneficial to utilize the integrator reset condition to Figure 1 The controller 50 is programmed to help avoid Figure 2-4 The PI regulator saturates, for example when the actual shunt angle or the machine temperature does not allow the calculated command to be achieved.

[0104] For example, the commanded torque (T * ) and the actual split angle (f shunt ) may be used as an input to the anti-windup logic 70 along with a possible forced reset signal (FW reset) (e.g., triggered by a calibrated elapsed time or in response to an error or other suitable condition). The maximum torque per shunt block 71 may be used to provide a torque (T) that is compared with the commanded torque (T) in the comparison block 73 (≥) * ) is compared to the torque value. As long as the maximum torque per split from block 71 does not exceed the commanded torque (T * ), the PI regulator can continue to integrate and accumulate errors. * ) exceeds the maximum torque per split or in response to a forced reset, an integrator reset (reset) occurs.

[0105] In view of the foregoing disclosure, as will be appreciated by one of ordinary skill in the art, the present method contemplates using current and shunt angle commands to quickly estimate the Figure 1 Instead of using full torque control of the motor 14 during transient response, the motor torque is controlled by the feedback loop depicted in the various figures (arrow T M ). The present method adjusts the d-axis current command and the q-axis current command to the motor 14 based on the commanded and actual shunt angles, wherein the estimated torque from the motor 14 is also provided by the shunt angle and the d-axis / q-axis current commands. Thus, the present method seeks to maintain a smooth torque transient response and torque accuracy during shunt angle transitions occurring within a VFM embodiment of the motor 14, even in the presence of shunt errors, wherein aspects of the present disclosure may be readily extended to thermal adaptation for PM motor variants. These and other benefits will be readily apparent to one of ordinary skill in the art in view of the foregoing disclosure.

[0106] Thus, the present disclosure implements a method for controlling transient operation of a rotating electrical machine 14. In an exemplary embodiment, this may be accomplished, for example, via Figure 3The torque control loop 150T of the motor 14 occurs during the shunt angle transition during the MTPA control region. An embodiment of this method may include: using the feedback d-axis current command and q-axis current command (i d * fd and i q * fd) and an additional value (i.e., the actual shunt angle f of the motor 14, depending on the configuration of the motor 14) shunt or temperature) to determine the estimated output torque (T est ).

[0107] This method may include: from the commanded torque T * The estimated torque is subtracted from the torque to derive the adjusted command torque value (T * adj); and calculating the Δd-axis current command I from the torque value of the adjusted command d_adj and the Δq-axis current command I q_adj The method may further include: adjusting the actual d-axis current command and the q-axis current command using the Δd-axis command and the Δq-axis command, respectively, via the controller 50, thereby generating a d-axis command i d * fd and q axis commands i q * fd,, and the controller 50 then provides the d-axis command and the q-axis command to the torque estimation block 40 as closed-loop feedback (fd) terms.

[0108] The detailed description and the accompanying drawings or figures support and describe the present teaching, but the scope of the present teaching is limited only by the claims. Although the best mode and some of the other embodiments for implementing the present teaching have been described in detail, there are various alternative designs and embodiments for practicing the present teaching defined in the appended claims. In addition, the present disclosure explicitly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A method for controlling transient operation of a rotating electrical machine, the method comprising: During a shunt angle transition occurring during a maximum torque per ampere MTPA control region of the motor, wherein the transition modifies the flux path within the motor and the back EMF of the motor: determining an estimated output torque of the electric machine via a torque estimation block within a torque loop of a controller using a d-axis current command, a q-axis current command, and an additional value, wherein the additional value is an actual shunt angle of the electric machine or a temperature of the electric machine; subtracting the estimated output torque from the commanded output torque to thereby derive an adjusted commanded torque value or torque error; Calculating a Δd-axis current command and a Δq-axis current command using the adjusted commanded torque value or torque error; adjusting a d-axis current command and a q-axis current command of the motor using the Δd-axis current command and the Δq-axis current command, respectively, via the controller; and The d-axis current command and the q-axis current command are provided to the torque estimation block as closed-loop feedback control terms.

2. The method according to claim 1, wherein: The rotating electrical machine is a variable flux electrical machine, and wherein the additional value is the actual shunt angle.

3. The method according to claim 1, wherein: The electric machine is a permanent magnet electric machine, and wherein the additional value is the temperature of the electric machine.

4. The method according to claim 1, further comprising: Feeding the DC bus voltage, torque conversion command and speed of the motor into separate d-axis current command lookup tables and q-axis current command lookup tables of the controller; as well as The Δd-axis current command and the Δq-axis current command are added to respective outputs of the separate d-axis current command lookup table and the q-axis current command lookup table, thereby deriving the d-axis current command and the q-axis current command.

5. The method according to claim 1, wherein: Calculating the Δd-axis current command and the Δq-axis current command includes: processing the torque value or torque error of the adjusted command through a proportional-integral (PI) regulator to generate a Δ steady-state current amplitude; adding the Δ steady-state current amplitude to the steady-state current amplitude to generate a new steady-state current value; processing the new steady-state current value through an MTPA β angle lookup table to generate a current command β angle of the motor; and using a transformation block of the controller to transform the current command β angle into adjusted d-axis values ​​and q-axis values.

6. The method according to claim 5, further comprising: The PI regulator is selectively and automatically reset in response to a predetermined condition.

7. The method according to claim 1, further comprising: During a field weakening control region of the electric machine occurring before or after the MTPA control region: regulating the d-axis current command using a modulation index control loop of the controller; and The q-axis current command is regulated via the torque control loop of the controller.

8. The method according to claim 7, further comprising: A calibrated torque hysteresis is used to avoid oscillations or jitters between the MTPA control region and the field weakening control region.

9. The method according to claim 1, wherein: Determining the estimated output torque includes determining a d-axis flux contribution and a q-axis flux contribution using a flux lookup table, and wherein the torque estimation block includes a lookup table indexed by the d-axis current command, the q-axis current command, the d-axis flux contribution, and the q-axis flux contribution.

10. An electric powertrain, comprising: a rotating electrical machine having phase windings; a traction power inverter module TPIM connected to the rotating electrical machine via the phase winding; as well as A controller having: A current control block connected to the TPIM, the current control block being configured to: receiving a d-axis current command and a q-axis current command; and outputting a d-axis voltage command and a q-axis voltage command to the TPIM in response to the d-axis current command and the q-axis current command; as well as a shunt control block configured to: transform an actual shunt angle of the motor during a maximum torque per ampere MTPA control region of the motor, thereby modifying a magnetic flux path within the motor and a back EMF of the motor; The controller is configured to: execute instructions to control transient operation of the rotating electrical machine, and the execution of the instructions causes the control system to: determining an estimated output torque of the rotating electric machine using a d-axis current command, a q-axis current command, and an additional value via a torque estimation block, wherein the additional value is an actual shunt angle of the electric machine or a temperature of the electric machine; subtracting the estimated output torque from the commanded output torque to thereby derive an adjusted commanded torque value or torque error; calculating a Δd-axis current command and a Δq-axis current command from the adjusted commanded torque value or torque error; adjusting an actual d-axis current command and an actual q-axis current command of the motor using the Δd-axis current command and the Δq-axis current command, respectively, thereby generating the d-axis command and the d-axis command; and The d-axis current command and the q-axis current command are provided to the torque estimation block as closed-loop feedback control terms.

11. The electric powertrain of claim 10, wherein: The rotating electrical machine is a variable flux electrical machine, and wherein the additional value is the actual shunt angle.

12. The electric powertrain of claim 10, wherein: The electric machine is a permanent magnet electric machine, and wherein the additional value is the temperature of the electric machine.

13. The electric powertrain of claim 10, wherein: The controller is configured to: Feeding the DC bus voltage, torque conversion command and speed of the motor into separate d-axis current command lookup tables and q-axis current command lookup tables; as well as The Δd-axis current command and the Δq-axis current command are added to respective outputs of the d-axis current command lookup table and the q-axis current command lookup table, thereby deriving the d-axis current command and the q-axis current command.

14. The electric powertrain of claim 10, wherein: The controller is configured to: Calculating the Δd-axis current command and the Δq-axis current command by processing the adjusted commanded torque value through a proportional-integral (PI) regulator, thereby generating a Δ steady-state current magnitude; adding the Δ steady-state current amplitude to the steady-state current amplitude to generate a new steady-state current value; Processing the new steady-state current value through the MTPA β angle lookup table to generate a current command β angle of the motor; as well as The current command β angle is transformed into adjusted d-axis and q-axis values ​​using a transformation block of the controller.

15. The electric powertrain of claim 14, wherein: The controller is configured to selectively and automatically reset the PI regulator in response to a predetermined condition.

16. The electric powertrain of claim 14, wherein: The controller is configured to: during a field weakening control region of the rotating electrical machine that occurs before or after the MTPA control region: regulating the d-axis current command using a modulation index control loop or a voltage control loop of the controller; and The q-axis current command is regulated via the torque control loop of the controller.

17. The electric powertrain of claim 16, wherein: The controller is configured to use a calibrated torque hysteresis to avoid oscillations between the MTPA control region and the field weakening control region.

18. The electric powertrain of claim 14, wherein: The controller is configured to determine the estimated output torque of the electric machine by determining a d-axis flux contribution and a q-axis flux contribution using a flux lookup table, and wherein the torque estimation block includes a lookup table indexed by the d-axis current command, the q-axis current command, the d-axis flux contribution, and the q-axis flux contribution.

19. The electric powertrain of claim 14, further comprising: A driven load is connected to the rotating electrical machine.

20. The electric powertrain of claim 19, wherein: The driven load comprises one or more road wheels of a motor vehicle.

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