Motor control system, motor control method and electric power steering system

Abstract

A motor control system, a method for controlling a motor, and an electric power steering system are provided. The motor generates an output current according to an input voltage command. The method receives an output current including a direct axis portion and an orthogonal axis portion from the motor, and the output current is received as a feedback current. The method determines a compensation voltage command by applying a first gain factor and an inverse of a second gain factor to the feedback current. The first gain factor decouples the d-axis portion and the q-axis portion of the compensation voltage command. The inverse of the second gain factor allows the compensation voltage command to be filtered in a manner that maintains decoupling between the d-axis and the q-axis. The method determines an input voltage command for the motor by applying the second gain factor to the compensation voltage command so that the motor generates an output current that is less affected by changes in the operating parameters of the motor.

Description

Background Art

[0001] The output torque of a permanent magnet synchronous motor (PMSM) (e.g., a surface permanent magnet (SPM) motor, an interior permanent magnet (IPM) motor, etc.) can be determined by a voltage command and a phase advance angle. For example, the output torque of the PMSM can be determined by first selecting a specific quadrature axis (also called q-axis) reference current and a direct axis (also called d-axis) reference current, and then determining a voltage command and a phase advance angle based on the selected quadrature axis reference current and the direct axis reference current.

[0002] An electric power steering (EPS) system uses an electric motor (e.g., a PMSM) to provide steering assistance. When a PMSM is used, field oriented control (FOC) is utilized, which allows the conversion of alternating current (AC) multiphase (e.g., three-phase) motor voltage and current signals into a synchronously rotating reference frame (commonly referred to as a d-axis / q-axis reference frame) where the motor voltage and current become direct current (DC) quantities. FOC torque control techniques are implemented using feedforward control methods or closed-loop current feedback control or some combination thereof. Summary of the invention

[0003] One aspect of the disclosed embodiment includes a motor control system that generates an output current based on an input voltage command. The motor control system includes at least one processor and a memory, the memory including instructions that, when executed by the at least one processor, cause the at least one processor to: receive an output current from a motor including a direct axis (d-axis) portion and an orthogonal axis (q-axis) portion, the output current being received as a feedback current. The at least one processor is also configured to: determine a compensation voltage command by applying a first set of gain factors and an inverse of a second set of gain factors to the feedback current, the first set of gain factors being used to decouple the d-axis portion and the q-axis portion of the compensation voltage command, the inverse of the second set of gain factors being used to allow filtering of the compensation voltage command in a manner that maintains decoupling between the d-axis portion and the q-axis portion. The at least one processor is also configured to: determine an input voltage command for the motor by applying the second set of gain factors to the compensation voltage command so that the motor generates an output current that is reduced in impact by changes in a set of operating parameters of the motor.

[0004] Another aspect of the disclosed embodiment includes a method of controlling a motor that generates an output current based on an input voltage command. The method includes receiving an output current from the motor that includes a direct axis (d-axis) portion and an orthogonal axis (q-axis) portion, the output current being received as a feedback current. The method also includes determining a compensation voltage command by applying a first set of gain factors and an inverse of a second set of gain factors to the feedback current, the first set of gain factors being used to decouple the d-axis portion and the q-axis portion of the compensation voltage command, the inverse of the second set of gain factors being used to allow the compensation voltage command to be filtered in a manner that maintains decoupling between the d-axis portion and the q-axis portion. The method also includes determining an input voltage command for the motor by applying a second set of gain factors to the compensation voltage command so that the motor generates an output current that is less affected by changes in a set of operating parameters of the motor.

[0005] One aspect of the disclosed embodiment includes an electric power steering (EPS) system. The EPS system includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: receive an output current from a motor including a direct axis (d-axis) portion and an orthogonal axis (q-axis) portion, the output current being received as a feedback current. The instructions, when executed by the processor, also cause the processor to: determine a d-axis portion of a voltage command and a q-axis portion of a voltage command by applying a set of gain factors to the feedback current. The instructions, when executed by the processor, also cause the processor to: determine a compensation voltage command by applying a first set of gain factors and an inverse of a second set of gain factors to the feedback current, the first set of gain factors being used to decouple the d-axis portion and the q-axis portion of the compensation voltage command, the inverse of the second set of gain factors being used to allow filtering of the compensation voltage command in a manner that maintains decoupling between the d-axis portion and the q-axis portion. The instructions, when executed by the processor, also cause the processor to: determine an input voltage command for the motor by applying the second set of gain factors to the compensation voltage command so that the motor generates an output current that is less affected by changes in a set of operating parameters of the motor.

[0006] These and other advantages and features will become more apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is best understood by the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily expanded or reduced for clarity.

[0008] Figure 1 A schematic diagram of a motor control system according to the principles of the present disclosure is generally shown.

[0009] Figure 2 A phasor diagram of a motor according to the principles of the present disclosure is generally shown.

[0010] Figure 3A and 3B A block diagram of a control system for noise cancellation using one or more modules in accordance with the principles of the present disclosure is generally shown.

[0011] Figure 4 Another block diagram of a control system for noise cancellation using one or more modules in accordance with the principles of the present disclosure is generally shown.

[0012] Figure 5 Another block diagram of a control system for noise cancellation using one or more modules in accordance with the principles of the present disclosure is generally shown.

[0013] Figure 6 Another block diagram of a control system for noise cancellation using one or more modules in accordance with the principles of the present disclosure is generally shown.

[0014] Figure 7 is a flow chart generally illustrating a control method for controlling a motor according to the principles of the present disclosure. DETAILED DESCRIPTION

[0015] The following discussion is directed to various embodiments of the disclosed subject matter. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used as limiting the scope of the present disclosure, including the claims. In addition, it will be understood by those skilled in the art that the following description has broad application, and the discussion of any embodiment is intended only to be an example of that embodiment, and is not intended to imply that the scope of the present disclosure, including the claims, is limited to that embodiment.

[0016] The output torque of a permanent magnet synchronous motor (PMSM) (surface permanent magnet (SPM) motor, interior permanent magnet (IPM) motor, etc.) can be determined by a voltage command and a phase advance angle. For example, the output torque of a PMSM can be determined by first selecting a specific q-axis reference current and a d-axis reference current, and then determining a voltage command and a phase advance angle based on the selected q-axis reference current and the d-axis reference current.

[0017] An electric power steering (EPS) system uses an electric motor (e.g., a PMSM) to provide steering assistance. When a PMSM is used, field oriented control (FOC) is utilized, which allows the conversion of alternating current (AC) multiphase (e.g., three-phase) motor voltage and current signals into a synchronously rotating reference frame (commonly referred to as a d-axis / q-axis reference frame) where the motor voltage and current become direct current (DC) quantities. FOC torque control techniques are implemented using feedforward control methods or closed-loop current feedback control or some combination thereof.

[0018] The application of closed-loop current control of PMSM to EPS systems has unique and demanding requirements beyond the ability of the control system to track the required assist torque command (i.e., motor torque command). Many of these requirements are related to the balance of torque response behavior, motor input disturbance characteristics, current measurement noise transfer characteristics, and robustness to the accuracy of estimated electric motor parameter estimates. Consistency of performance is required over the entire operating range of the control system, including operation over the entire motor speed range and operation near the power supply voltage limits. Unlike high-voltage power supply applications utilizing PMSM, the power supply voltage available for control systems in vehicles is not unlimited, and the size of the motors used in these applications is typically designed as efficiently as possible to provide steady-state power requirements. This requires current control to operate in a stable and predictable manner because the transient voltage available to the control system becomes smaller near the peak power point of PMSM operation. Therefore, the control system should be configured to operate as required while requiring relatively small motor (input) voltage command transients.

[0019] In some cases, attempts to achieve consistent high performance are made by implementing a model in the control system to decouple the d-axis voltage and the q-axis voltage. Decoupling the d-axis voltage and the q-axis voltage eliminates the effects of changes in d-axis terms (e.g., d-axis inductance, d-axis current, etc.) on the q-axis voltage command, and eliminates the effects of changes in q-axis terms (e.g., q-axis inductance, q-axis current, etc.) on the d-axis voltage command. This enables the q-axis current and the d-axis current to be controlled independently of each other.

[0020] Additionally, stringent noise, vibration, and harshness (NVH) requirements may be imposed on motor drive applications (e.g., such as applications within EPS systems, etc.). To address this issue, some electric motor drive applications use filtering techniques to attenuate unwanted noise bands in different signal paths. For example, noise in the paths of commanded current and / or measured current can be attenuated by applying filtering techniques to specific signal paths.

[0021] However, applying filtering techniques to the voltage command can couple or recouple the d-axis portion and the q-axis portion of the voltage command. The coupling or recoupling causes NVH-related disturbances, which negatively impact the voltage command used by the motor to determine the output current.

[0022] Therefore, systems and methods (e.g., such as those described herein) are desired that filter out NVH-related disturbances while maintaining decoupling of the d-axis and q-axis portions of the voltage command. In some embodiments, the systems and methods described herein may be configured to control the output current based on an input voltage command as follows: NVH-related disturbances are filtered out using a transfer matrix, and by implementing an inverse transfer matrix in a state feedback loop of the control system to maintain decoupling of the d-axis and q-axis portions of the voltage command. The systems and methods described herein may be configured to filter the input voltage command provided to the motor without removing the decoupling of the d-axis and q-axis portions of the voltage command. The systems and methods described herein may be configured to eliminate the effects of NVH-related disturbances on the operating parameters of the motor, enabling the motor to achieve consistent high performance.

[0023] Figure 1 1 shows a control system 100 according to the principles of the present disclosure. As shown, the motor control system 100 includes a motor 20, an inverter 22, a voltage source 24, and a control module 30 (also referred to as a controller). The voltage source 24 supplies a power supply voltage V to the motor 20. B . In some embodiments, voltage source 24 is a 12 volt battery. However, it should be understood that other types of voltage sources may also be used. Inverter 22 is connected to motor 20 via multiple connections 32 (e.g., three connectors) labeled "A", "B", and "C". In some embodiments, motor 20 is a multi-phase permanent magnet (PM) brushless motor. In this example, motor 20 is a three-phase PM motor. Control module 30 is connected to motor 20 via inverter 22. For example, control module 30 receives a motor torque command T from a source 34 such as a steering control system. CMD The control module 30 includes control logic for sending an input voltage command V to the motor 20 via the inverter 22. M .

[0024] Reference now Figure 1 and Figure 2 , running the motor 20, so that the input voltage command V M The phase of the developed back electromotive force (BEMF) voltage E of the motor 20 is g The phase shift of Figure 2 The phasor diagram of the motor 20 is shown in FIG. 1 , which shows that the magnitude is the input voltage command V M The voltage vector V of the BEMF voltage vector E is the magnitude of the BEMF voltage E g The angle between the voltage vector V and the BEMF voltage vector E is defined and is referred to as the phase advance angle δ. The stator phase current is referred to as I and the stator phase current on the orthogonal axis (q axis) is referred to as I q , the stator phase current on the direct axis (d axis) is called Id , the corresponding stator phase reactance on the d-axis is called X d , the stator phase reactance on the q axis is called X q , the stator phase resistance of phase A, phase B or phase C is called R.

[0025] In some embodiments, encoder 36 ( Figure 1 ) measuring the rotor of the motor 20 ( Figure 1 The angular position θ of the motor 20 is used to determine the input phase voltage V a 、V b and V c , where the input phase voltage V a Corresponding to connection A, the input phase voltage V b Corresponding to connection B, the input phase voltage V c Corresponding to connection C. In some embodiments, the control module may include logic for determining the duty cycle of the corresponding phase arm of the inverter 22. For example, a sinusoidal voltage may be applied at the terminals of the motor 20 using the duty cycle, and the duty cycle may be determined using any known pulse width modulation (PWM) technique (e.g., a sinusoidal PWM technique, a space vector PWM technique (e.g., continuous, discontinuous, etc.), a technique using harmonic injection, etc. In some embodiments, the duty cycle may be converted into an on-time based on a switching or PWM period, and the duty cycle may be sent to a gate driver that applies a gate signal to the corresponding switch of the inverter 22.

[0026] The motor 20 rotates in both clockwise and counterclockwise directions and can also generate both clockwise and counterclockwise torque during operation.

[0027] Figure 3A A block diagram of a control system 100 using one or more modules in accordance with the principles of the present disclosure is generally shown. The control module 30 may include a BEMF compensation module 302, a subtraction module 304, a compensation and integration module 306, an addition module 310, 312, and 314, respectively, and a correction module 316. The control module 30 may include modules in addition to those described herein, and may additionally include fewer modules than those generally shown and described herein. Figure 3A Also shown is a frequency conversion module P(s) that can be implemented using the motor 20. To simplify the illustration and description, Figure 3A The inverter 22 between the control module 30 and the motor 20 is not shown.

[0028] The motor 20 can receive an input voltage command V M and can generate torque (e.g., draw or generate current I P , which can be a combination of Figure 1and Figure 2 The motor 20 may be controlled by the control module 30 so as to generate a voltage according to an input signal (ie, an input voltage command V M ) to generate a frequency response (e.g., torque or current drawn / sourced I P ) device. It will be appreciated that the frequency response generated by the motor 20 can be controlled by a set of model equations that define one or more transfer functions to convert the input voltage command V M Converted to output current I P In other words, the control module 30 can generate an input voltage command V based on the model by sending M To adjust the output current I P .

[0029] In some embodiments, the control module 30 may include a feedback controller with a closed loop. dist and the noise current I noise With the output current I P are added (eg, using summing module 312 and summing module 314 , respectively) to determine the feedback current I that is provided back to the control module 30 . M This enables the control module 30 to use the feedback current I M To adjust the output current I of the motor 20 generated subsequently P In some embodiments, a current sensor (not shown) can measure the feedback current I M The feedback current I M The current measurement results are provided to the control module 30.

[0030] In some embodiments, the correction module 316 may receive the feedback current I M For example, the correction module 316 may receive the feedback current I from the motor 20 , the summing module 314 , a sensor, etc. M .

[0031] In some embodiments, the correction module 316 can be based on the feedback current I M The input voltage command V M The d-axis portion V d and q-axis part V q By decoupling the input voltage command V M The d-axis portion V d , the correction module 316 eliminates the change of the q-axis term to the input voltage command V M The influence of the d-axis part of the voltage command is reduced, and the influence of the change of the d-axis term on the q-axis part of the voltage command is eliminated.

[0032] In some embodiments, the correction module 316 can generate a compensation voltage command V H , the compensation voltage command V H Offset or compensate the input voltage command V M The compensation voltage command V H Can be used to generate a decoupled input voltage command V M , the decoupled input voltage command V M When provided to the motor 20, the motor 20 generates a frequency response (eg, output current I P ).

[0033] In some embodiments, the subtraction module 304 can determine the difference current I E For example, the subtraction module 304 can determine the commanded current I R The measured current I M The difference current I E In some embodiments, the subtraction module 304 can convert the difference current I E Provided to the compensation and integration module 306.

[0034] In some embodiments, the compensation and integration module 306 may include a proportional controller. Additionally or alternatively, the compensation and integration module 306 may include an integral controller.

[0035] In some embodiments, the proportional controller can be configured to assist the motor 20 in generating a frequency response that is a first order type response. In some embodiments, the proportional controller can be configured to assist the motor 20 in generating a frequency response that is a higher order type response (e.g., second order response, third order response, etc.).

[0036] In some embodiments, the compensation and integration module 306 (eg, using a proportional compensation submodule C P (s)) can be calculated based on the difference current I provided by the subtraction module 304 E Generate proportional voltage command V P This allows the proportional controller to provide a beneficial compromise between the motor input disturbance transfer function behavior and the current measurement noise transfer function behavior.

[0037] In some embodiments, the integral controller may receive the differential current I E , the integral controller may be the compensation and integration module 306 (e.g., in Figure 4-6 In some embodiments, the integral controller may determine the integral voltage command V I , and the integrated voltage command V IProvided to an addition module (eg, which may be included in the compensation and integration module 306). In some embodiments, the addition module may be configured to generate a proportional voltage command V P And the integrated voltage command V I Add to determine the compensation voltage command V C . Compensation voltage command V C may be provided to the filtering module 318 along with one or more other compensation voltage commands, as will be further described herein.

[0038] In some embodiments, the BEMF compensation module 302 can be configured to compensate for the dynamics (e.g., changes) of the BEMF voltage that are slower than the dynamics of the stator phase current of the motor 20. For example, the BEMF compensation module 302 can be configured to receive the rotor mechanical speed ω m As input, it generates a dynamic compensation voltage command V to compensate the BEMF voltage. F In some embodiments, the BEMF compensation module 302 can set the compensation voltage command V F Provided to the adding module 308.

[0039] In some embodiments, the summing module 308 may add one or more compensation voltages to generate a total (known) compensation voltage command V R For example, the adding module 308 can convert the compensation voltage command V H and compensation voltage command V C summed to determine the total (known) compensation voltage command V R , the total (known) compensation voltage command V R This allows the motor 20 to generate a stable frequency response that is not affected by the dynamics of the resistance of the motor 20 and / or any inaccurate estimates of the resistance. As described herein, the total (known) compensation voltage command V R may refer to a total compensation voltage command known or determined within the control module 30. Similarly, as described herein, the total compensation voltage command V M It may refer to an unknown disturbance V originating from outside the control module 30. dist The total compensation voltage command.

[0040] Figure 3B The block diagram of the control system 100 is generally shown, which uses the filtering module 318 and the inverse filtering module 320 for noise cancellation. In some embodiments, the summing module 308 can be a total (known) compensation voltage command V R Provided to the filter module 318. In some embodiments, the filter module 318 can calculate the total (known) compensation voltage command V R Filtering (for example, to output the filtered compensation voltage command ). For example, the filtering module 318 can use the transfer matrix F(s) to calculate the total (known) compensation voltage command V R Filtering, as will be shown further herein. The total (known) compensation voltage command V R A d-axis portion and a q-axis portion may be included.

[0041] In some embodiments, the filtering module 318 can use a set of low-pass filters to perform filtering. Additionally or alternatively, the filtering module 318 can use a lead-lag filter to perform filtering. Additionally or alternatively, the filtering module 318 can use a control band-stop filter (notch filter) to perform filtering. Additional information about each corresponding type of filtering is further provided herein.

[0042] In some embodiments, the inverse filtering module 320 can be used to maintain decoupling between the d-axis and the q-axis. For example, the inverse filtering module 320 can be implemented as part of a feedback loop to determine a compensation voltage command V that can be provided to and used by the filtering module 318. H . Compensation voltage command V H In some embodiments, the inverse filtering module 320 may determine the compensated voltage command V by applying a set of gain factors to the output of the correction module 316 using a transfer matrix for one or more filters. H Additional information on gain factors and filtering is provided further in this article.

[0043] In some embodiments, the adding module 310 can convert the filtered voltage command and unknown interference V dist Add together to determine the total compensation voltage command V M (In this article, it is called input voltage command V M ), which includes unknown disturbances originating from outside the control module 30 (e.g., V dist ). For example, V dist It may represent an unknown input disturbance inherent in the control system 10 or a device or machine utilizing the control system 10 .

[0044] In some embodiments, the adding module 310 can convert the input voltage command V M Provided to the motor 20. In this way, the motor 20 receives the input voltage command V M , which decouples the d-axis portion and the q-axis portion and does not include NVH-related disturbances that have been filtered out by the filtering module 318 .

[0045] Figure 4A block diagram of a control module 30 according to the principles of the present disclosure is shown. In particular, the module is illustrated as including transfer matrices, which include transfer matrices for one or more low-pass filters. It should be noted that the module is illustrated as including these matrices to facilitate understanding regarding what operations the module is configured to perform.

[0046] In some embodiments, the control module 30 is configured to generate the input voltage command V using the motor control model of the following phase voltage equations: M :

[0047]

[0048]

[0049]

[0050] In the above equation, V d and V q are the d-axis motor voltage and the q-axis motor voltage (in volts), I d and I q are the d-axis motor current and the q-axis motor current (in amperes), L d and L q are the d-axis motor inductance and the q-axis motor inductance (in henries), R is the resistance of the motor circuit (i.e., motor and controller) (in ohms), and K e is the motor BEMF factor (in volts / radian / second), ω m is the mechanical speed of the motor (in radians per second); N p is the number of poles of motor 20, T e is the electromagnetic motor torque in Newton meters.

[0051] It should be noted that the torque T used to calculate the electromagnetic motor e Equation 3 is nonlinear and represents the torque generated by utilizing the magnetic field from the permanent magnet and the torque generated by the rotor characteristics (ie, L d and L q The difference between d and I q The following document describes the method for optimizing the reference current I d and I qSelection of a reference model design for PMSM control: U.S. patent application entitled "Generation of a Current Reference to Control a Brushless Motor" filed on November 26, 2013, with agent case number "N000153(NXT0175US2)", the entire contents of which are incorporated herein by reference.

[0052] The parameters in Equations 1-3 vary widely during normal operation of the motor 20 - R may vary by more than 100%, the inductance L d and L q The change may exceed 5-20%, K e R may vary with the build and temperature of the motor 20. d and L q changes due to saturation (i.e., I d and I q function), and K e Due to saturation changes (I q function of temperature).

[0053] Some embodiments are described herein in conjunction with a transfer matrix. In one or more of these embodiments, the transfer matrix may be a dynamic transfer matrix. That is, the gains (i.e., terms) included in the transfer matrix may be dynamic values ​​updated in real time or near real time. To provide a specific example, the transfer matrix H and the transfer matrix F -1 (s) (described further herein) can be a dynamic transfer matrix as part of a state feedback loop.

[0054] In equations 1 and 2, is the electric motor speed ω of motor 20 e The electric motor speed is assumed to be a slowly varying parameter. The BEMF has been compensated using the BEMF compensation module 302. However, the BEMF of the motor 20 may represent unknown or inherent disturbances originating from outside the control module 30 (and thus may also need to be filtered). Due to the relatively slow flux dynamics, the quasi-static back electromotive force (BEMF) term K e ,ω m can be considered as a constant and can be compensated as another disturbance using the compensation module. The addition module adds this disturbance to the input voltage command V M These two assumptions linearize equations 1 and 2 for a fixed speed of the motor 20. Therefore, equations 1 and 2 can be rewritten as the following linear equations 4 and 5, respectively:

[0055]

[0056]

[0057] In addition, Equation 4 and Equation 5 can be shortened using the s-domain representation as:

[0058] U=P i (s)X (Equation 6)

[0059]

[0060] In the above equation, U can be the input voltage matrix P i (s) can be a complex frequency transfer matrix And X can be a matrix In Equation 7, the output current matrix X of the motor 20 is converted into a complex frequency transfer matrix P i (s) is converted into the input voltage matrix U. The complex frequency transfer matrix P i (s) is the inverse of the real transfer matrix P(s) (e.g., P(s) may be the actual device transfer matrix). i (s) Figure 4 is shown as being included in the motor 20. i (s) can also be expressed as P -1 , to show that P i (s) is the inverse of P(s). Note that P i Elements of (s) rather than P(s) are shown as included in motor 20 to correspond to elements included in the transfer matrix H (described further herein).

[0061] The actual device transfer matrix P(s) that converts input voltage to output current can be written as:

[0062] X = P(s)U (Equation 8)

[0063]

[0064] Where P(s) is

[0065] In some embodiments, the correction module 316 can convert the coupling terms (or transfer matrix P) in equations 4 and 5 into i (s) or the corresponding elements in the transfer matrix P(s)). For example, the correction module 316 can use the transfer matrix H to decouple the coupling terms in equations 4 and 5 (or the transfer matrix P i (s) or the corresponding elements in the transfer matrix P(s)). Specifically, the off-diagonal elements of the transfer matrix H are selected to eliminate P iThe off-diagonal elements of H(s) correspond to the coupled terms of Equations 4 and 58. The off-diagonal elements of H(s) can be expressed as follows:

[0066]

[0067]

[0068] In equations 10 and 11, is the estimated electric motor speed of motor 20, is the estimated q-axis inductance of the motor 20, is the estimated d-axis inductance of the motor 20 .

[0069] The correction module 316 can also make the motor 20 insensitive to changes in motor operating parameters (i.e., reduce the impact of changes), especially insensitive to changes in motor resistance, so that the motor 20 generates a stable frequency response (e.g., output current). The diagonal elements of the transfer matrix H can be expressed as follows:

[0070] K Hdd =-R d (Equation 12)

[0071] K Hdq =-R q (Equation 13)

[0072] In equations 12 and 13, -R d and -R q is the virtual impedance value (in ohms). Select R d and R q value, and is specifically configured to balance the control system's sensitivity to motor parameter changes (specifically, resistance changes, which typically fluctuate by up to 100% with temperature), voltage disturbance rejection transfer function characteristics, and current measurement noise sensitivity characteristics. In addition, since -R d and -R q , the time for the motor 20 to respond to the voltage command is shortened or reduced (ie, a faster response time is obtained). Therefore, the transfer matrix H can be written as:

[0073]

[0074] It is noted that these elements of the transfer matrix H are scheduled according to the motor parameters, which are non-linear and vary continuously with the operating conditions of the motor (eg, temperature, resistance, etc.).

[0075] In some embodiments, for example, when the filtering module 318 is used to filter NVH-related disturbances (as further described herein), the filtering will result in the compensation voltage command VM For example, the filter module 318 may receive the compensation voltage command V H , compensation command voltage V C and / or compensation voltage command V F , these compensation voltage commands can be collectively referred to as compensation voltage commands V R .

[0076] In some embodiments, the filter module 318 may use the transfer matrix F LP To compensate the voltage command V R The NVH-related interference is filtered in the transfer matrix F LP exist Figure 4 The following is shown below:

[0077]

[0078] In some embodiments, Can be equal to Wherein, τ represents the low-pass filter time constant. In some embodiments, in the transfer matrix F LP Medium and low pass filters Can be applied to compensate voltage command V R In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be compared with the compensation voltage command V R In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be applied to the compensation voltage command V R The values ​​of the q-axis portion vary with the filter values.

[0079] In some embodiments, the inverse filtering module 320 may determine the compensation voltage command V in a manner that maintains the decoupling of the d-axis and the q-axis. H . Compensation voltage command V H The compensation d-axis component and the compensation q-axis component may be included. For example, the correction module 316 may maintain decoupling by using a first set of gain factors (described elsewhere herein) to generate the compensation voltage command V H , the compensation voltage command V H Offset or compensate the input voltage command V M In order to maintain decoupling, the inverse filtering module 320 can be used to filter the coupled current, inductance, stator resistance changes, measurement inaccuracies, etc. by using a transfer matrix of one or more low-pass filters. A second set of gain factors is applied to the output of the correction module 316 to determine the compensation voltage command V H . Transfer matrix For example, it can be a dynamic gain transfer matrix. exist Figure 4 The following is shown below:

[0080]

[0081] The transfer matrix shown in Equation 16 middle, represents an approximation of the variable s, which can be realized in discrete time and can be expressed as τ represents the low-pass filter time constant, Indicates the compensation voltage command V applied to H The low-pass filter cutoff frequency of the d-axis portion, Indicates the compensation voltage command V applied to H The low-pass filter cutoff frequency of the q-axis portion of the filter (eg, a low-pass filter, another type of filter described herein, or any other suitable filter) may represent a cutoff frequency, a cutoff amplitude, a cutoff phase characteristic value, a cutoff pitch characteristic value, and the like.

[0082] Due to interference and noise (i.e., V dist ,I dist and I noise ),like Figure 4 As shown (I dist and I noise The output current I P (combined), the transfer matrix of the motor 20 seen by the control module 30 is not P(s). That is, the actual transfer matrix of the motor 20 seen by the control module 30 should take into account all interference and noise. In this disclosure, the actual transfer matrix seen by the control module 30 is referred to as the effective transfer matrix P eff The modified effective transfer matrix P eff is defined as:

[0083] P eff =(F -1 (s)(P i (s)-H(s))) -1 (Equation 17)

[0084] That is, P eff It can be defined as F -1 (s)(P i (s)-H(s)). Therefore, the effective inverse transfer matrix P ieff F -1 (s)(P i (s)-H(s)), can be written in matrix form as:

[0085]

[0086]

[0087] In some embodiments, the diagonal elements of the transfer matrix H (ie, K Hdd and K Hdq ) can be configured to have a negative value to ensure that P ieff The corresponding diagonal elements of are positive. It can be understood that P ieff The diagonal elements (RK Hdd ) and (R–K Hdq ) should be greater than zero (i.e., a positive resistance value) in order to maintain the stability of the motor 20 in the presence of resistance changes. These elements in the and is an accurate estimate of the effective motor transfer matrix P eff Can be defined as:

[0088]

[0089] Understandable, P. ieff The diagonal elements (R–K Hdd ) and (R–K Hdq ) should be greater than zero (ie, a positive resistance value) in order to maintain the stability of the motor 20 in the presence of resistance changes.

[0090] The control module 30 can set the compensation voltage command V M The d-axis part and the compensation voltage command V M The q-axis part is decoupled so that the compensation voltage command V M The d-axis portion of the current does not affect the q-axis portion of the current, and makes the compensation voltage command V M The q-axis part of the current does not affect the d-axis part of the current. In addition, by using the transfer matrix H and the transfer matrix To maintain the voltage command V M The d-axis part and the q-axis part are decoupled to generate the compensation voltage command V H , the control module 30 saves resources (e.g., processing resources, memory resources, etc.) relative to a suboptimal system that can only couple or recouple the compensation voltage command V M The d-axis part and the q-axis part are used to filter the NVH-related disturbances. Figure 5 and Figure 6 Other example filters are described.

[0091] Figure 5A block diagram of a control module 30 is shown in accordance with the principles of the present disclosure. In particular, the module is shown to include transfer matrices including transfer matrices for one or more lead-lag filters.

[0092] Transfer matrix F LL exist Figure 5 The following is shown below:

[0093]

[0094] In the transfer matrix F LL In the lead-lag filter Can be applied to compensate voltage command V R In some embodiments, Can be equal to Wherein, τ represents the low-pass filter time constant. In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be compared with the compensation voltage command V R In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be applied to the compensation voltage command V R The values ​​of the q-axis portion vary with the filter values.

[0095] Transfer Matrix exist Figure 5 The following is shown below:

[0096]

[0097] In the transfer matrix Inverse lead-lag filter Can be applied to compensate voltage command V H In some embodiments, the compensation voltage command V H The filter value of the d-axis portion can be compared with the compensation voltage command V H In some embodiments, the compensation voltage command V H The filter value of the d-axis portion can be applied to the compensation voltage command V H The values ​​of the q-axis portion vary with the filter values.

[0098] By implementing the transfer matrix in the state feedback loop The transfer matrix F can be used LL Filtering the NVH-related interference while allowing the compensation voltage command V output by the filter module 318 to be maintained M The d-axis part and the q-axis part are decoupled.

[0099] Figure 6 A block diagram of a control module 30 according to the principles of the present disclosure is shown. In particular, the module is illustrated as including transfer matrices including transfer matrices for one or more control band-stop filters (notch filters). It should be noted that the module is illustrated as including these matrices to facilitate easy understanding of what operations the module is configured to perform.

[0100] Transfer matrix F N exist Figure 6 The following is shown below:

[0101]

[0102] In the transfer matrix F N In this case, a notch filter can be applied Where ζ is the damping ratio and ω is the voltage command V that can be applied to the compensation R In some embodiments, Can be equal to Wherein, τ represents the low-pass filter time constant. In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be compared with the compensation voltage command V R In some embodiments, the compensation voltage command V R The filter value of the d-axis portion can be applied to the compensation voltage command V R The values ​​of the q-axis portion vary with the filter values.

[0103] Transfer Matrix exist Figure 6 The following is shown below:

[0104]

[0105] In the transfer matrix Inverse notch filter Can be applied to compensate voltage command V H In some embodiments, the compensation voltage command V H The filter value of the d-axis portion can be compared with the compensation voltage command V H In some embodiments, the compensation voltage command V H The filter value of the d-axis portion can be applied to the compensation voltage command V H The values ​​of the q-axis portion vary with the filter values.

[0106] By implementing the transfer matrix in the state feedback loop The transfer matrix F can be used N Filtering the NVH-related interference while allowing the compensation voltage command V output by the filter module 318 to be maintained M The d-axis part and the q-axis part are decoupled.

[0107] Figure 7 is a flow chart of a control method 700 that can be performed by the control system 100 (e.g., using the control module 30) according to the principles of the present disclosure. In some embodiments, the control module 30 can be implemented as part of a motor control system that generates an output current based on an input voltage command. In some embodiments, the control module 30 can be implemented as part of an electric power steering (EPS) system using a processor and a memory. As can be understood from the present disclosure, the sequence of operations within the method is not limited to the following. Figure 7 Rather, the sequences shown are not intended to be performed in the order shown, but may be performed in one or more different sequences as applicable in accordance with the principles of the present disclosure.

[0108] At 710, the method 700 receives an output current including a direct axis (d-axis) portion and an orthogonal axis (q-axis) portion from the motor 20, wherein the output current can be received as a feedback current. For example, the control module 30 can receive an output current including a direct axis (d-axis) portion and an orthogonal axis (q-axis) portion from the motor 20, wherein the output current can be received as a feedback current.

[0109] At 720, the method 700 determines the compensation voltage command by applying the inverse of the first set of gain factors and the second set of gain factors to the feedback current. For example, the control module 30 can determine the compensation voltage command by applying the inverse of the first set of gain factors and the second set of gain factors to the feedback current. The first set of gain factors can decouple the d-axis portion and the q-axis portion of the compensation voltage command. The inverse of the second set of gain factors can be used to filter the compensation voltage command in a manner that maintains the decoupling between the d-axis portion and the q-axis portion of the compensation voltage command.

[0110] In some embodiments, at least one of the second set of gain factors or the inverse of the second set of gain factors may be applied by using a transfer matrix for one or more low pass filters by control module 30. In some embodiments, the transfer matrix may be a dynamic gain transfer matrix:

[0111]

[0112] In some embodiments, at least one of the second set of gain factors or the inverse of the second set of gain factors may be applied by using a transfer matrix for one or more lead-lag filters by the control module 30. In some embodiments, the transfer matrix may be a dynamic gain transfer matrix:

[0113]

[0114] In some embodiments, at least one of the second set of gain factors or the inverse of the second set of gain factors may be applied by using a transfer matrix for one or more notch filters by control module 30. In some embodiments, the transfer matrix may be a dynamic gain transfer matrix:

[0115]

[0116] In some embodiments, at least one of the second set of gain factors may be applied by control module 30 using a transfer matrix of a first type of filter for d-axis values ​​and a second type of filter for q-axis values. In some embodiments, the first set of gain factors may include one or more virtual impedances.

[0117] At 730 , method 700 determines an input voltage command for motor 20 by applying a second set of gain factors to the compensation voltage command such that motor 20 generates an output current to reduce the effects of changes in the set of operating parameters of motor 20 .

[0118] The above discussion is intended to illustrate the principles and various embodiments of the present disclosure. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. It is intended that the following claims be interpreted to include all such changes and modifications.

[0119] The word "example" is used herein to mean used as an example, instance or illustration. Any aspect or design described herein as an "example" is not necessarily to be interpreted as being more preferred or advantageous than other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a specific way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clearly seen from the context, "X includes A or B" is intended to represent any natural inclusive arrangement. That is, if X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied in any of the foregoing cases. In addition, the article "one" used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clearly pointed to the singular form from the context. In addition, unless so described, the use of the term "embodiment" or "one embodiment" throughout the text is not intended to represent the same embodiment or embodiment. Some embodiments are described herein in conjunction with thresholds.

[0120] Furthermore, as used herein, the term "set" is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.) and may be used interchangeably with "one or more." Figure 1In the case of multiple items, the term "a" or similar language is used. Moreover, as used herein, the terms "having" and the like are intended to be open-ended terms. In addition, unless expressly stated otherwise, the phrase "based on" is intended to mean "based at least in part on."

[0121] As used herein, satisfying a threshold may refer to a value being greater than a threshold, exceeding a threshold, above a threshold, greater than or equal to a threshold, less than a threshold, less than a threshold, below a threshold, less than or equal to a threshold, equal to a threshold, etc.

[0122] The implementation of the systems, algorithms, methods, instructions, etc. described herein may be implemented in hardware, software, or any combination thereof. The hardware may include, for example, a computer, an intellectual property (IP) core, an application specific integrated circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuit. In the claims, the term "processor" shall be understood to include any of the foregoing hardware, alone or in combination. The terms "signal" and "data" are used interchangeably.

[0123] As used herein, the terms "module" and "sub-module" refer to an ASIC, an electronic circuit, a processor (shared processor, dedicated processor, or processor group) and memory that executes one or more software or firmware programs, a combination of logic circuits, and / or other suitable components that provide the functionality. When implemented in software, a module or sub-module can be implemented in a memory as a non-transitory machine-readable storage medium that can be read by a processing circuit and stores instructions executed by the processing circuit to perform the method. In addition, the modules and sub-modules described herein can be combined and / or further divided.

[0124] As used herein, the term module may include a packaged functional hardware unit designed to be used with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), a processing circuit configured to perform a specific function, and a self-contained hardware or software component that interfaces with a larger system. For example, a module may include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an electrical circuit, a digital logic circuit, an analog circuit, a combination of discrete circuits, a gate circuit, and other types of hardware or combinations thereof. In other embodiments, a module may include a memory that stores instructions executable by a controller to implement the features of the module.

[0125] Furthermore, in one aspect, for example, the systems described herein may be implemented using a general purpose computer or general purpose processor with a computer program that, when executed, implements any corresponding method, algorithm and / or instruction described herein. Additionally or alternatively, for example, a special purpose computer / processor may be used that may include other hardware for implementing any method, algorithm or instruction described herein.

[0126] In addition, all or part of the implementation of the present disclosure may take the form of a computer program product accessible from, for example, a computer usable or computer readable medium. A computer usable or computer readable medium may be, for example, any device that can tangibly contain, store, communicate, or transport a program for use by or in conjunction with any processor. The medium may be, for example, an electronic, magnetic, optical, electromagnetic device, or a semiconductor device. Other suitable media may also be used.

[0127] The above embodiments, implementations and aspects have been described to allow easy understanding of the invention and are not intended to limit the invention. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted by law.

Claims

1. A motor control system that generates an output current according to an input voltage command, the motor control system include: at least one processor; as well as a memory comprising instructions that, when executed by the at least one processor, cause the at least one processor to: receiving the output current including a direct d-axis portion and an orthogonal q-axis portion from the motor, the output current being received as a feedback current; determining a compensation voltage command by applying a first set of gain factors to the feedback current and an inverse of a second set of gain factors to allow filtering of the compensation voltage command in a manner that maintains decoupling between the d-axis and q-axis portions of the compensation voltage command; as well as An input voltage command to the motor is determined by applying the second set of gain factors to the compensation voltage command such that the motor generates an output current that is less susceptible to changes in a set of operating parameters of the motor.

2. The motor control system according to claim 1, in, The instructions further cause the processor to apply at least one of the second set of gain factors or an inverse of the second set of gain factors using a transfer matrix for one or more low pass filters.

3. The motor control system according to claim 2, in, The transfer matrix includes a dynamic gain transfer matrix.

4. The motor control system according to claim 1, in, The instructions further cause the at least one processor to apply at least one of the second set of gain factors or an inverse of the second set of gain factors using a transfer matrix representing one or more lead-lag filters.

5. The motor control system according to claim 4, in, The transfer matrix includes a dynamic gain matrix.

6. The motor control system according to claim 1, in, The instructions further cause the at least one processor to apply at least one of the second set of gain factors or an inverse of the second set of gain factors using a transfer matrix for one or more notch filters.

7. The motor control system according to claim 6, in, The transfer matrix includes a dynamic gain matrix.

8. The motor control system according to claim 1, in, The first set of gain factors includes one or more virtual impedances.

9. A method of controlling a motor, the motor generating an output current according to an input voltage command, the method include: receiving the output current including a direct d-axis portion and an orthogonal q-axis portion from the motor, the output current being received as a feedback current; determining a compensation voltage command by applying a first set of gain factors to the feedback current and an inverse of a second set of gain factors to allow filtering of the compensation voltage command in a manner that maintains decoupling between the d-axis and q-axis portions of the compensation voltage command; as well as An input voltage command to the motor is determined by applying the second set of gain factors to the compensation voltage command such that the motor generates an output current that is less susceptible to changes in a set of operating parameters of the motor.

10. The method according to claim 9, in, At least one of the second set of gain factors is applied using a transfer matrix of a first type of filter for d-axis values ​​and a second type of filter for q-axis values.

11. The method according to claim 9, in, At least one of the second set of gain factors or an inverse of the second set of gain factors is applied using one or more low pass filters that are a portion of a dynamic transfer matrix.

12. The method according to claim 9, in, At least one of the second set of gain factors or an inverse of the second set of gain factors is applied using a transfer matrix for one or more lead-lag filters.

13. The method according to claim 12, in, The transfer matrix is ​​a dynamic gain matrix.

14. The method according to claim 9, in, At least one of the second set of gain factors or an inverse of the second set of gain factors is applied using a transfer matrix for one or more notch filters.

15. The method according to claim 14, in, The transfer matrix is ​​a dynamic gain matrix.

16. An electric power steering EPS system, include: processor; as well as a memory comprising instructions that, when executed by the processor, cause the processor to: receiving an output current including a direct d-axis portion and an orthogonal q-axis portion from the motor, the output current being received as a feedback current; determining a compensation voltage command by applying a first set of gain factors to the feedback current and an inverse of a second set of gain factors to allow filtering of the compensation voltage command in a manner that maintains decoupling between the d-axis and q-axis portions of the compensation voltage command; receiving the compensation voltage command; as well as An input voltage command to the motor is determined by applying the second set of gain factors to the compensation voltage command such that the motor generates an output current that is less susceptible to changes in a set of operating parameters of the motor.

17. The EPS system according to claim 16, in, The compensated voltage command is determined by applying the inverse of the second set of gain factors such that a d-axis portion of the voltage command and a q-axis portion of the voltage command remain decoupled when provided to the motor.

18. The EPS system according to claim 16, in, The instructions also cause the processor to apply at least one of the second set of gain factors using a transfer matrix of a first type of filter for d-axis values ​​and a second type of filter for q-axis values.

19. The EPS system according to claim 18, in, The transfer matrix includes a dynamic gain matrix.

20. The EPS system according to claim 16, in, The first set of gain factors includes one or more virtual impedances.

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