Motor control

Abstract

Examples include a method of controlling an electric motor using a variable speed drive based on input parameters of the variable speed drive. The method uses initial estimated parameters of the electric motor and measured values of the variable speed drive at an operating point of the electric motor to determine accurate input parameters of the variable speed drive.

Description

Technical Field

[0001] This invention relates to a method for controlling an electric motor. Background Technology

[0002] Many electric motors are driven by variable speed drives. The parameters of the motor driven by the variable speed drive can be used to configure the variable speed drive, thereby improving the control of that motor.

[0003] However, setting the speed drive using motor parameters requires knowledge of the motor, which is not always available and, when available, is not necessarily accurate.

[0004] Therefore, it is necessary to determine the accurate setting parameters of the motor and provide them to the variable speed drive for better motor control. Summary of the Invention

[0005] Therefore, the purpose of this disclosure is to provide a method for controlling an electric motor using a variable speed drive, which allows for the real-time calculation of the variable speed drive's setting parameters.

[0006] Another objective of this disclosure is to allow motor users to control the motor based on calculated settings to improve the control of the variable speed drive.

[0007] To achieve these objectives, this disclosure proposes determining a set of VSD parameters based on a representation model of the electric motor and measurements from a variable speed drive controlling the motor. VSD parameters refer to the input parameters of the variable speed drive controlling the electric motor. VSD parameters may correspond to parameters of the electric motor. The representation model of the electric motor refers to one or more equations that represent the difference between initial estimates of one or more motor parameters and the actual values ​​of one or more motor parameters at the motor's operating point; and one or more equations that allow the determination of the theoretical response of the motor at the operating point based on the initial estimates of one or more parameters. Therefore, this disclosure proposes determining refined estimates of the motor parameters of the representation model based on measurements from the variable speed drive in order to determine an accurate set of VSD parameters to improve the control of the electric motor.

[0008] This disclosure describes a method for controlling an electric motor using a variable speed drive, the method comprising:

[0009] - Apply one or more electrical commands to the motor via a variable speed drive, causing the motor to operate at one or more defined operating points;

[0010] - For each defined operating point, the actual operating parameters in the motor are determined by the speed drive based on the measurements taken by the speed drive at that operating point;

[0011] - For each defined operating point, estimated operating parameters in the motor are determined by initial estimates of motor parameters from a motor-based representation model of the variable speed drive and electrical commands associated with the operating point;

[0012] - For each defined operation point, calculate the operation difference based on the actual operation parameters and the estimated operation parameters;

[0013] - For each given operating point, the value of at least one operating coefficient is determined by the variable speed drive based on the operating difference and the motor's representation model;

[0014] - By using a variable speed drive, a refined estimate of at least one motor parameter of the representation model is determined based on at least one operating coefficient and the representation model determined at each operating point;

[0015] - The value of the VSD parameter set is determined by the variable speed drive based on a refined estimate of at least one motor parameter, the VSD parameter set including at least two VSD parameters.

[0016] This control method allows for the real-time determination of the VSD parameter set based on refined estimates of motor parameters. Using this VSD parameter set as input to the variable speed drive for controlling the motor improves motor control. Furthermore, this control method determines a VSD parameter set applicable to each motor, thus allowing for improved control of multiple motors via the variable speed drive.

[0017] Optionally, the representation model includes electrical or mechanical parameters of the motor. This representation model allows the motor to be controlled based on its electrical or mechanical aspects via a variable speed drive.

[0018] Alternatively, the representation model can be built based on the motor's default parameter set. Initializing the estimated motor parameters based on the default parameter set allows for improved accuracy in determining the VSD parameters with fewer operating points.

[0019] In some examples, the default parameter set includes the motor's nameplate values. These nameplate parameters allow for the determination of initial estimates of the motor parameters representing the model based on information provided by the motor manufacturer at the start of the method.

[0020] Optionally, the method further includes an updated representation model based on refined estimates of at least one determined motor parameter. The updated representation model allows for refinement of the motor's representation model over the motor's lifespan.

[0021] Optionally, the method further includes:

[0022] - When the distance between at least one previously stored operating coefficient is greater than a determined threshold, the value of the at least one operating coefficient is stored in the transmission drive.

[0023] This distance allows for more accurate determination of refined estimates of motor parameters, and consequently, more accurate determination of the values ​​for the VSD parameter set.

[0024] Optionally, the estimated operating parameters and the actual operating parameters are respectively an estimated vector and an actual vector comprising several values, and the operating difference corresponds to the difference in the norms of the estimated vector and the actual vector. This allows the theoretical and actual responses of the motor to be determined based on several values ​​(i.e., several data points) that can be used to determine the representation model of the motor.

[0025] Optionally, the method further includes determining a performance value for the representation model based on the value of the electrical command and the operational difference determined at the operating point. The performance value allows the performance of the motor controlled by the variable speed drive to be determined based on the current values ​​of the motor parameters of the representation model.

[0026] Optionally, the method includes continuing to execute the method when the performance value falls below a determined threshold. This allows for refinement of the VSD parameter set if the latter is determined based on a representation model with lower accuracy than expected.

[0027] Optionally, the method further includes controlling the motor via a variable speed drive based on a stored set of VSD parameters. This allows motor control based on a set of VSD parameters stored in the variable speed drive, which can be refined by the method at each iteration.

[0028] Optionally, the VSD parameter set includes at least two of the following: stator resistance, no-load current, leakage inductance, rotor time constant, load torque, and motor inertia. These parameters can characterize many motors and therefore can be used in many representation models of motors.

[0029] Optionally, a type is assigned to the motor, and the method further includes storing a motor dataset in a remote server, the motor dataset including the determined VSD parameter set, the motor type, and the motor's operating time. This allows for the calculation of statistics for each of the plurality of motors controlled by the variable speed drive performing the method presented herein.

[0030] This disclosure also proposes a method for processing motor data, including classifying motors based on the evolution of their VSD parameter set during operating time. For example, this allows for the identification of some production lines that perform better than others in relation to the evolution of their motor's VSD parameters, thereby identifying potential problems on those production lines.

[0031] The processing method for motor data also includes determining a set of predicted VSD parameters for a given running time based on several datasets containing specific types of motors.

[0032] This allows, for example, setting an accurate VSD parameter set for a motor driven by a variable speed drive that might not be compatible with the methods presented herein. Furthermore, determining the prediction set allows for setting accurate VSD parameters directly for the variable speed drive controlling the motor based on the specific type and operating time of the motor.

[0033] This disclosure also describes a computer-readable storage medium including instructions that, when executed by a processor, cause the processor to perform any of the methods described above.

[0034] This disclosure also describes a variable speed drive including a processor adapted to control an electric motor according to any of the methods described above. Attached Figure Description

[0035] Figure 1 An example of a motor controlled by a variable speed drive is shown.

[0036] Figure 2 The first example method is shown.

[0037] Figure 3a The first example of the VSD parameter group is shown.

[0038] Figure 3b The first example of a set of motor parameters representing a model is shown.

[0039] Figure 3c The first example of an equation representing a model is shown.

[0040] Figure 3d A first example of a VSD parameter set determined based on a motor parameter set is shown.

[0041] Figure 4 A second example method is shown.

[0042] Figure 5a A second example of the VSD parameter group is shown.

[0043] Figure 5b A second example of a set of motor parameters representing a model is shown.

[0044] Figure 5c A second example of an equation representing the model is shown.

[0045] Figure 5d A second example of a VSD parameter set determined based on a motor parameter set is shown.

[0046] Figure 6 The third example method is shown.

[0047] Figure 7aThe third example of the VSD parameter group is shown.

[0048] Figure 7b A third example of a set of motor parameters representing a model is shown.

[0049] Figure 7c A fourth example of a set of motor parameters representing a model is shown.

[0050] Figure 7d A third example of an equation representing the model is shown.

[0051] Figure 7e A third example of a VSD parameter set determined based on a motor parameter set is shown.

[0052] Figure 8 The fourth example method is shown.

[0053] Figure 9a The fifth example of a set of motor parameters representing a model is shown.

[0054] Figure 9b Examples illustrate the relationship between some operating coefficients and the initial and refined estimates of motor parameter sets.

[0055] Figure 9c A fourth example of a VSD parameter set determined based on a motor parameter set is shown. Detailed Implementation

[0056] This disclosure applies to control methods for electric motors using variable speed drives.

[0057] In this disclosure, a variable speed drive should be understood as an electronic, virtual, or software-implemented control unit for an electric motor. The variable speed drive can control the motor using electrical commands and, in particular, can apply a defined voltage to the motor. In some examples, the variable speed drive includes a processing and control unit designed to implement a control law by considering, for example, an input speed setpoint, the voltage applied to the motor during normal operation, and control commands to be applied to an inverter stage to obtain these output voltages. The control law can be of vector or scalar type. The variable speed drive may include a rectifier stage at the input designed to convert AC voltage supplied by the power grid into DC voltage. In some examples, the rectifier stage may be a half-wave rectifier. The variable speed drive may also include a direct power bus connected on one side to the rectifier stage and on the other side to the inverter stage. The DC power bus may include two power lines connected together by at least one bus capacitor or Zener diode configured to stabilize the bus voltage. The rectifier can be of a passive type, such as a diode bridge, or of an active type based on controlled transistors. The inverter stage can be connected to the output of the DC power bus and is used to cut off the voltage supplied to the motor by the bus at a variable voltage. The inverter stage may include, for example, multiple switching arms, each including a controlled power transistor, such as an IGBT, for applying the variable voltage to the motor. The inverter can be controlled, for example, using conventional techniques such as PWM (Pulse Width Modulation) or vector control. The control law executed by the processing unit allows the voltage to be determined for the output phase intended to be connected to the motor to be controlled.

[0058] In this disclosure, "electric motor" should be understood as any kind of electric motor that can be driven by a variable speed drive. The electric motor can be a motor controlled by AC voltage, such as an induction motor. In some examples, the electric motor can be a synchronous motor or an asynchronous motor.

[0059] Figure 1 An example system comprising an electric motor controlled by a variable speed drive is shown. System 1 includes a power grid 2 supplying three-phase AC voltage to the variable speed drive 3. The variable speed drive 3 includes a rectifier stage 31 connected to the power grid 2 and converting the three-phase AC voltage to DC voltage. The variable speed drive also includes an inverter stage 32 to convert the DC voltage to a controlled AC voltage for operating the electric motor 4. The variable speed drive includes a processor PROC, such as a controller or microcontroller. The processor PROC may include PWM (Pulse Width Modulation) functionality to control the conversion from DC voltage to controlled AC voltage. The processor PROC is configured to operate according to any of the methods described herein. The processor PROC may include electronic circuitry for calculations managed by an operating system.

[0060] The variable speed drive 3 may include a non-transitory machine-readable or computer-readable storage medium, such as a memory or storage cell MEM, wherein the non-transitory machine-readable storage medium is encoded with instructions executable by a processor, such as a processor PROC, and the machine-readable storage medium includes instructions for operating the processor PROC to execute according to any of the example methods described herein. The computer-readable storage according to this disclosure may be any electronic, magnetic, optical, or other physical storage device storing executable instructions. The computer-readable storage may be, for example, random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), storage drives, and optical discs, etc. As described herein, computer-readable storage can be encoded with executable instructions according to the methods described herein. Storage or memory may include any electronic, magnetic, optical, or other physical storage device storing executable instructions as described herein.

[0061] The variable speed drive may include a stored set of VSD parameters. This stored set of VSD parameters can be used to control the motor via the variable speed drive.

[0062] In the control method described below, the variable speed drive applies one or more electrical commands to the motor.

[0063] Electrical commands:

[0064] The electrical commands applied to the motor may include a voltage of a defined frequency. The voltage may be between 5V and 1kV, and preferably between 300V and 600V. The defined frequency may be between 10Hz and 100kHz, and preferably between 1kHz and 20kHz. The electrical commands applied to the motor may drive the motor to operate at its operating point.

[0065] Operation points:

[0066] The operating point of an electric motor can include its speed, acceleration, and torque. The speed of the motor can be expressed in revolutions per minute (rpm) and can be between 0 and 10,000 rpm, preferably between 1,000 and 3,000 rpm. The torque of the motor can be expressed in Newton-meters (Nm) and can be between 0 and 10 kNm, preferably between 0 and 1,000 Nm. In some examples, the torque of the motor corresponds to the electromagnetic torque τ of the motor. em The operating point is reached when the variable speed drive applies an electrical command to the motor.

[0067] In the control methods described below, one motivation for the control method is to determine a VSD parameter group that includes at least two VSD parameters.

[0068] VSD parameters:

[0069] In this disclosure, VSD parameters should be understood as input parameters of the variable speed drive used to control the electric motor.

[0070] This set of VSD parameters is determined based on refined estimates of one or more motor parameters representing the model.

[0071] In this disclosure, the refined estimates of the motor parameters should be understood as the values ​​of the motor parameters in the representation model determined during the iteration of the method proposed herein.

[0072] Representation model:

[0073] A motor representation model refers to one or more equations that represent the difference between an initial estimate of one or more motor parameters and the actual value of one or more motor parameters at the motor's operating point; and one or more equations that allow the determination of the motor's theoretical response at the operating point based on the initial estimates of one or more parameters.

[0074] In this disclosure, the initial estimates of the motor parameters should be understood as the values ​​of the motor parameters in the representation model estimated at the start of an iteration of the method proposed herein.

[0075] In this disclosure, the initial estimate of the motor parameter "mp" will be labeled as The detailed estimated value of the motor parameter "mp" will be marked as follows: The actual value of the motor parameter "mp" is then labeled as mp.

[0076] Examples of representation models of electric motors may include multiple equations, each of which includes at least one motor parameter from the set of motor parameters representing the model.

[0077] In some examples, the representation model of an electric motor may include a master equation and a sub-equation.

[0078] In this disclosure, the master equation should be understood as an equation that includes all motor parameters representing the set of motor parameters of the model.

[0079] In this disclosure, a sub-equation should be understood as an equation that includes at least one motor parameter representing the model. A sub-equation representing the model may be an equation that includes one or more motor parameters representing the model.

[0080] In some examples, a linear approximation of the principal equation can be applied to obtain the principal or sub-equations of the representation model based on another principal equation of the representation model. In some examples, Taylor polynomials can be used to approximate the principal equation. In some examples, the sub-equations can be determined by projecting the principal equation onto a subspace that includes fewer motor parameters. The sub-equations reduce the number of motor parameters so that their refined estimates can be determined by running the motor at fewer operating points.

[0081] Example methods will be provided to better understand the claimed invention.

[0082] Example Method 100:

[0083] refer to Figure 2 Example method 100 is presented. In example method 100, the motor controlled by the variable speed drive is an asynchronous motor and can be controlled by the variable speed drive in an open loop. By using the open loop approach, it should be understood in example method 100 that the variable speed drive does not measure the rotor speed ω of the motor at the operating point. r Therefore, variable speed drives cannot be based on rotor speed ω. r Determine the slip speed ω of the asynchronous motor g The actual value of slip velocity ω. g The synchronous speed ω corresponding to the asynchronous motor s and rotor speed ω r The difference between them.

[0084] One of the goals of Example Method 100 is to determine a set of VSD parameters, including four VSD parameters, based on refined estimates of three motor parameters and an initial estimate of one motor parameter from the representation model of Example Method 100. The four VSD parameters include the no-load current I0. v Stator resistance R s Leakage inductance L f and rotor time constant T r . Figure 3a An example of the VSD parameter group Svp2 of example method 100 is shown.

[0085] The first equation that allows the determination of the representation model of example method 100 for the VSD parameter set Svp2 is:

[0086]

[0087] in:

[0088] This is the initial estimate of the stator resistance (stator resistance is a motor parameter).

[0089] This is the initial estimate of the leakage inductance (leakage inductance is a motor parameter).

[0090] This is the initial estimate of the specific inductance (specific inductance is a motor parameter).

[0091] This is the initial estimate of the specific resistance (leakage inductance is a motor parameter).

[0092] ω S It is the synchronous speed of the electric motor.

[0093] It is an estimate of the slip velocity.

[0094] Δi dq It is the current difference, corresponding to the estimated current of the motor at the operating point. The actual current I determined by the measurement value of the motor. dq The difference between

[0095] V represents the estimated value of the motor parameters at the operating point. The actual value of the motor parameters (R) s ,L f ,L,R req The difference in the operation coefficient.

[0096] Different inductances can be represented by Henry (H). Different resistances can be represented by Ohm (Ω).

[0097] The specific inductance L can be based on the mutual inductance L m and rotor inductance L r To estimate, the specific inductance L can be equal to:

[0098]

[0099] Leakage inductance L f It can be based on mutual inductance L m Stator inductance Ls and rotor inductance L r To estimate. Leakage inductance L f It can be equal to:

[0100]

[0101] resistivity R req It can be based on the rotor resistance R r Rotor inductance L r and mutual induction L m To estimate. Specific resistance R req It can be equal to:

[0102]

[0103] Estimated current and actual current I dq It is a vector consisting of two components. The first component is I. d This is the current component along the direct axis (d-axis) of the Park coordinate system. The second component I... q It is the current component in the second-order axis (q-axis) of the Park coordinate system.

[0104] As indicated by the first equation (which is the principal equation), the representation model of the electric motor in Example Method 100 includes four motor parameters. These four motor parameters form the motor parameter group Smp2, as shown below. Figure 3b As shown. The first equation is expressed in the Park coordinate system, which includes the d and q coordinates.

[0105] As shown in the equation, the value of the operating coefficient V depends on the estimated current Δi. dq and actual current I dq The difference in current between Current difference The initial estimates of the set Smp2, representing the motor parameters of the model at the operating point, are characterized. The actual values ​​of the motor parameters (R) of the electric motor s ,L f ,L,R req The difference between them.

[0106] Current difference Δi dq Allows for the calculation of detailed estimates of motor parameters.

[0107] Some refined estimates of the motor parameters can be used to determine the VSD parameter set Svp2, such as Figure 3d As indicated by the arrow, it shows which refined estimate and which initial estimate of the motor parameters of motor parameter group Smp2 are used to determine VSD parameter group Svp2 in this example.

[0108] Therefore, one of the goals of Example Method 100 is to determine refined estimates of the motor parameters representing the model. To determine the VSD parameter group Svp2.

[0109] The second equation representing the model can be calculated from the first equation using a second-order linear approximation:

[0110]

[0111] in:

[0112] δR S This is the initial estimate of the stator resistance. The actual value R of the stator resistance s The difference between them;

[0113] δL f This is the initial estimate of the leakage inductance. The actual value of leakage inductance L f The difference between them;

[0114] It is the reciprocal of the initial estimate of the inductance. The reciprocal of the actual value of the inductance The difference between them;

[0115] It is the estimated slip velocity at the defined operating point divided by the initial estimated resistivity. Its actual value The difference between them;

[0116] v1 is based on the initial estimate of the stator resistance at the determined operating point. and actual current I dq Estimated operating coefficients

[0117] v2 is based on an initial estimate of the leakage inductance at a given operating point. Synchronous speed ω S and actual current I dq Estimated operating coefficients

[0118] v3 is based on the specific resistance at a defined operating point. Inductance Initial estimates and slip velocity estimates Synchronous speed ω S and the actual current I at the determined operating point dq Estimated operating coefficients

[0119] v4 is based on resistivity at a defined operating point. Inductance Initial estimates and slip velocity estimates Synchronous speed ω S and actual current I dq Estimated operating coefficients.

[0120] The second equation of the representation model in example method 100 (which is also the main equation since the second equation includes all motor parameters of motor parameter group Smp2) includes the actual values ​​of the motor parameters (R). s ,L f ,L,R req However, the second equation representing the model does not allow for the actual value of resistivity R. req The actual value of the slip speed ω of the electric motor g Separately. As mentioned above, in an open-loop system, the transmission drive cannot access the actual value ω of the slip speed.g Therefore, example method 100 does not allow for situations where the actual value of the slip velocity ω is unknown. g Determining detailed estimates of motor parameters under these circumstances The initial estimate of the resistivity With rotor time constant T r Connected arrows Figure 3d As shown, this is because example method 100 does not allow for the determination of a refined estimate of the specific resistance. Therefore, the variable speed drive will be based on a refined estimate of the specific inductance. and estimated value of resistivity Determine the rotor time constant T r In the form of the second equation representing the model of example method 100, the variable speed drive also cannot obtain refined estimates of other motor parameters.

[0121] The representation model of example method 100 therefore includes a third equation (which is a sub-equation) calculated from the second equation using the projection of the second equation into the subspace:

[0122]

[0123] in:

[0124] Q is based on the stator resistance at a given operating point. Leakage inductance resistivity Inductance Initial estimate, slip velocity The estimated value, synchronization speed ω S and current difference The estimated operating coefficients

[0125] Q RS Based on stator resistance at a defined operating point resistivity Inductance The initial estimates and the estimated slip velocity. The estimated operating coefficients

[0126] q Lf Based on leakage inductance at a defined operating point resistivity Inductance The initial estimates and the estimated slip velocity. The estimated operating coefficients

[0127] q L It is based on the initial estimate of the specific inductance at a defined operating point. and synchronization speed ωS The estimated operating coefficients

[0128] The third equation of the model in example method 100 does not include the actual value ω connected to the slip velocity. g Any item, therefore, except for the motor parameter R s ,L f Apart from the actual value of L, all terms in the third equation are known. Therefore, the third equation has three values ​​to be determined, which are the actual values ​​of the motor parameters R. s ,L f And L. In fact, the three values ​​to be determined correspond to the refined estimates of three motor parameters.

[0129] In this example, the variable speed drive allows for operation based on the corresponding operating coefficient q of the motor parameters. Rs ,q Lf and q L And the operating coefficient Q to determine the refined estimates of motor parameters As mentioned above, the operating coefficients Q,q Rs ,q Lf and q L The transmission drive is connected to the operating point of the motor. Therefore, at three different operating points, the transmission drive defines a system of three equations with three values ​​to be determined. The transmission drive can solve these values ​​to determine refined estimates of the motor parameters. Then, refined estimates of the motor parameters will be used. To determine the VSD parameter set. An example of the representation model for example method 100 is in... Figure 3c The second and third equations are shown and included.

[0130] The following is an example method 100 for finding the value of the VSD parameter group Svp2.

[0131] As shown in block 110, example method 100 includes applying three electrical commands via a variable speed drive to achieve three defined operating points of the motor.

[0132] As shown in block 120, example method 100 includes determining the actual current I by the speed drive for each defined operating point based on measurements taken by the speed drive at the operating point. dq Actual current I dq This corresponds to the current of the motor at each operating point. More precisely, the actual current I. dq It is determined based on three measured currents I1, I2, and I3, which correspond to the current in each winding of the motor at the operating point. In some examples, the actual current I... dq The norm is equal to:

[0133]

[0134] in:

[0135] |I dq | is the actual current I of the motor. dq norm,

[0136] I d It is the first component of the current on the direct axis (d-axis) of the Park coordinate system, and can be determined based on the measured currents I1, I2, and I3 in the motor windings.

[0137] I q It is the second component of the current on the secondary axis (q-axis) of the Park coordinate system, and can be determined based on the measured currents I1, I2, and I3 in the windings of the motor.

[0138] In this disclosure, different currents can be represented by amperes (A).

[0139] Actual current I dq Depends on the actual values ​​of the motor parameters representing the model (R) s ,L f ,L,R req This is because it is determined based on measurements of the transmission drive at the operating point. Actual current I dq It also depends on the electrical commands applied to the motor to reach the operating point.

[0140] In example method 100, the actual current I dq This corresponds to the actual operating parameter Opr associated with the operating point. The actual operating parameter Opr characterizes the motor's actual response at the operating point and is determined based on measurements taken from the variable speed drive at that point.

[0141] As shown in block 130, example method 100 includes determining an estimated current in the motor by the variable speed drive for each defined operating point.

[0142] Estimated current The stator resistance is based on the electric motor representation model. Leakage inductance resistivity and inductance The initial estimate is derived from the electrical command applied to the motor to reach the operating point. In other words, the estimated current at each operating point... It is estimated based on the initial estimated values ​​of motor parameters and electrical commands.

[0143] Estimated current The estimated operating parameter Ope corresponds to the operating point associated with example method 100. The estimated operating parameter Ope can characterize the theoretical response of the motor at the operating point, determined based on the initial estimates of the motor parameters.

[0144] As shown in block 140, example method 100 includes calculating the current difference Δi by the variable speed drive for each determined operating point. dq Current difference Δi dq Corresponding to the estimated current of the motor at the operating point The actual current I of the motor at the operating point dq The difference between Therefore, the current difference Δi dq This represents the initial estimate of the motor parameter set Smp2 of the model at the operating point. The actual value of the motor parameters (R) s ,L f ,L,R req The difference between them.

[0145] Current difference Δi dq This corresponds to the operating difference Opd associated with the operating point of example method 100. The operating difference Opd represents the difference between the theoretical response and the actual response of the motor at the operating point.

[0146] As shown in block 150, example method 100 includes the variable speed drive operating at each determined operating point based on the current difference Δi. dq The third equation of example method 100 determines the operation coefficients Q,q. Rs ,q Lf ,q L Therefore, at each operating point, the value of the operating coefficient is estimated based on the motor's representation model and the operating difference Opd.

[0147] At this point in example method 100, the transmission drive has already determined the operating coefficient set for each operating point. In some examples, the operating coefficient set for the first operating point could be (Q1, q1...). Rs ,q1 Lf and q1 L The set of operation coefficients for the second operation point can be (Q2, q2). Rs ,q2 Lf and q2 L And the set of operation coefficients for the three operation points can be (Q3, q3) Rs ,q3 Lf and q3 L Therefore, the variable speed drive obtains a system with three equations:

[0148] 1)

[0149] 2)

[0150] 3)

[0151] The arrows in method 100, which connects block 150 to block 110, illustrate the fact that, in this example, the transmission drive runs three times from block 110 to block 150 to determine the operating coefficient associated with each of the three determined operating points.

[0152] As shown in block 160, example method 100 includes determining the stator resistance by the variable speed drive. Leakage inductance and inductance The refined estimates are determined based on the set of operating coefficients determined at each operating point and the third equation. and By solving the above system problem, the stator resistance of the variable speed drive can be determined. Leakage inductance and inductance This provides refined estimates, allowing the VSD to "know" these values. In some examples, a matrix can be used to determine the actual values ​​of the motor parameters:

[0153]

[0154] Where w corresponds to

[0155] x corresponds to and

[0156] y corresponds to

[0157] Therefore, the variable speed drive can reduce the stator resistance Leakage inductance and inductance The refined estimate is determined to be equal to the stator resistance R. s Leakage inductance L f The actual value of the inductance L can be determined, for example, by matrix inversion and by calculating w, x, and y. In reality, due to imperfections in measurement, different approximations of the model equations, and the calculation of different coefficients, we cannot know whether the value we are determining is the actual value of the motor parameters. This is why this disclosure uses the term "refined estimate," which refers to a value that is closer to the actual value of the motor parameters than the initial estimate.

[0158] The electric motor representation model of Example Method 100 requires three operating points to determine the stator resistance. Leakage inductance and inductance The refined estimate. However, there may be more than three operation points, such as n operation points (n>3), and obtain the values ​​needed to determine three values. A system of n equations, where n is greater than three and n is a natural integer. In other words, to determine the stator resistance... Leakage inductance and inductance The refined estimate, example method 100, requires at least three operating points. When there are more than three equations (n>3), a system with n equations having three values ​​to be determined will have no solution. Therefore, the variable speed drive can determine the stator resistance using a recursive least squares algorithm. Leakage inductance and inductance The refined estimate is obtained. More generally, the refined estimate of the variable speed drive can be determined based on a linear regression model.

[0159] As shown in block 170, example method 100 includes a variable speed drive based on stator resistance. Leakage inductance and inductance Detailed estimates and initial estimates of resistivity Determine the four values ​​of the VSD parameter group Svp2. This block is as follows: Figure 3d As shown. Detailed estimates of the leakage inductance of the motor parameters. Allows direct determination of the leakage inductance L of this group of VSD parameters. f Detailed estimate of stator resistance in motor parameters. Allows direct determination of the stator resistance R of the VSD parameter set s Detailed estimates of the specific inductance of the motor parameters. Allows indirect determination of the no-load current I of VSD parameter group Svp2 v Detailed estimate of inductance It also allows for the indirect determination of the rotor time constant T. r The rotor time constant T r Also based on the initial estimate of the resistivity And estimates.

[0160] Here, "directly determined" means that the value of the VSD parameter is directly equal to the refined estimate of the motor parameters. "Indirectly determined" means that the value of the VSD parameter can be determined based on the refined estimate of the motor parameters.

[0161] Example method 100 allows for improved control of a motor using a variable speed drive by determining the values ​​of the VSD parameter set in the open loop. The values ​​of this VSD parameter set are determined based on refined estimates of the motor's electrical parameters that are closer to the actual values ​​of the motor parameters than the initial estimates.

[0162] Example method 200:

[0163] refer to Figure 4 Example method 200 is presented. In example method 200, the motor controlled by the variable speed drive is an asynchronous motor and can be controlled by the variable speed drive in a closed loop. In example method 200, the closed loop should be understood as the variable speed drive measuring the rotor speed ω of the asynchronous motor at the operating point. r Therefore, the variable speed drive can determine the actual value of the slip speed ωg of the asynchronous motor based on the rotor speed ωr. That is, the variable speed drive measures the rotor speed ωg of the motor at the operating point. r .

[0164] One of the goals of Example Method 200 is to determine a set of VSD parameters, including four VSD parameters, based on refined estimates of the four motor parameters of the representation model of Example Method 200. The four VSD parameters include the no-load current I0. v Rotor time constant T r Stator resistance R s and leakage inductance L f . Figure 5a An example of the VSD parameter group Svp3 of example method 200 is shown. VSD parameter group Svp3 includes the same parameters as VSD parameter group Svp2.

[0165] The first equation that allows the determination of the representation model of example method 200 for the VSD parameter set Svp3 is:

[0166]

[0167] The first equation of the representation model in example method 200 is similar to the first equation of the representation model in example method 100, the difference being the estimation of slip velocity. The value is no longer an estimate but the actual value of the slip velocity ω. g Because of the motor control in the closed loop, the variable speed drive can calculate the actual value ω of the slip speed. g Therefore, the representation model of example method 200 includes, for example, Figure 5b The motor parameter group Smp3 shows the four motor parameters.

[0168] The second equation of the representation model of example method 200 can be computed from the first equation based on a second-order linear approximation:

[0169]

[0170] The second equation of the representation model in example method 200 is similar to the second equation of the representation model in example method 100, except for the last term, because the transmission drive can calculate the actual value ω of the slip velocity at each operating point. g .

[0171] The operating coefficients v1 and v2 of the second equation in Example Method 200 are estimated based on the same values ​​as those in the second equation of Example Method 100. Similarly, the operating coefficients V, v3, and v4 of the second equation in Example Method 200 are also estimated based on the same values ​​as those in the second equation of Example Method 100, except for the estimated slip velocity. ω is replaced by the actual value of the slip velocity. g .

[0172] In Example 200, the actual value ω of the slip velocity can be accessed. g The variable speed drive can therefore determine the actual value of the motor parameter R. req .

[0173] The representation model of example method 200 includes a third equation (which is a sub-equation) calculated from the second equation based on the projection of the second equation of example method 200 into the subspace:

[0174]

[0175] The third equation of the representation model in example method 200 is similar to the third equation of the representation model in example method 100. The same references apply to the same objects.

[0176] The operand q in the third equation of example method 200 L It is obtained based on the same values ​​as the third equation in example method 100. The operational coefficients Q,q of the third equation in example method 200 are also relevant. Rs ,q Lf They are also estimated based on the same values ​​as the third equation of example method 100, except for the estimated slip velocity. The actual value of the slip velocity ω g replace.

[0177] In some examples, the operation coefficient Q can be equal to:

[0178]

[0179] in:

[0180]

[0181]

[0182]

[0183]

[0184] and

[0185] In some examples, the operation coefficient q RS It can be equal to:

[0186]

[0187] In some examples, the operation coefficient q Lf It can be equal to:

[0188]

[0189] In some examples, the operation coefficient q L It can be equal to:

[0190]

[0191] By calculating the real value ω of the slip velocity at the operating point. g The representation model of example method 200 also includes a fourth equation (which is also a sub-equation) calculated from the second equation based on the projection of the second equation into the subspace:

[0192]

[0193] in:

[0194] R is based on the stator resistance at a given operating point. Leakage inductance resistivity Inductance The initial estimate, synchronization speed ω S The actual value of slip velocity ω g and current difference Estimated operating coefficients

[0195] r RS Based on the stator resistance at a given operating point resistivity Inductance The initial estimate and the actual value of the slip velocity ω g The estimated operating coefficients

[0196] r Lf Based on leakage inductance at a defined operating point resistivity Inductance The initial estimate and the actual value of the slip velocity ω g and synchronization speed ω SThe estimated operating coefficients

[0197] r rreq Based on the specific resistance at a given operating point Inductance The initial estimate and the actual value of the slip velocity ω g And synchronization speed estimation ω S The operation coefficient.

[0198] In some examples, the operation coefficient R can be equal to:

[0199]

[0200] Where T1,E d ,T2,E q This corresponds to the same expression for the operation coefficient Q mentioned above.

[0201] In some examples, the operation coefficient r RS It can be equal to:

[0202]

[0203] In some examples, the operation coefficient r Lf It can be equal to:

[0204]

[0205] In some examples, the operation coefficient r Rreq It can be equal to:

[0206]

[0207] Example of the representation model for example method 200 is in Figure 5c The second, third, and fourth equations are shown and included.

[0208] The variable speed drive knows all the terms of the third equation, except for the stator resistance R. s Leakage inductance L f Given the actual value of the inductance L and knowing all the terms of the fourth equation except for the stator resistance R, we can determine the inductance L. s Leakage inductance L f and resistivity R req The actual value. Due to the stator resistance R s Leakage inductance L f Both actual values ​​are included in the third and fourth equations of the representation model of Example Method 200, so these two equations include the four refined estimates to be determined.

[0209] Therefore, in this example, the variable speed drive uses two operating points to determine a system with four equations having four values ​​to be determined, and the variable speed drive solves the system to determine the stator resistance. Leakage inductance Inductance and specific resistance The refined estimate.

[0210] The following is an example method 200 for finding the value of the VSD parameter group Svp3.

[0211] As shown in block 210, example method 200 includes applying two electrical commands via a variable speed drive to achieve two defined operating points.

[0212] As shown in block 220, example method 200 includes determining the actual current I by the speed drive for each determined operating point based on measurements taken by the speed drive at the operating point. dq and the actual value of slip velocity ω g .

[0213] slip velocity ω g Based on the rotor speed ω of the motor at a given operating point r It is determined by measurement.

[0214] Actual current I dq The current corresponding to the motor at each operating point is determined by the variable speed drive based on three measured currents I1, I2, and I3, which correspond to the current in each winding of the motor, as presented in the example method 100 above.

[0215] In some examples, the actual current i dq The norm is equal to:

[0216]

[0217] in:

[0218] |I dq | is the actual current I of the motor. dq norm,

[0219] I d It is the current component on the direct axis (d-axis) of the Park coordinate system, and can be determined based on the measured currents I1, I2, and I3 in the motor windings.

[0220] I q It is the current component on the secondary axis (q-axis) of the Park coordinate system, and can be determined based on the measured currents I1, I2 and I3 in the motor windings.

[0221] Actual current Idq It depends on the actual values ​​of the motor parameters representing the model, as it is determined based on measurements of the variable speed drive at the operating point. Actual current I dq It also depends on the electrical command applied to the motor to reach the operating point. Actual current I dq The actual operation parameter Opr corresponds to the operation point associated with example method 200.

[0222] As shown in block 230, example method 200 includes determining an estimated current in the motor by the variable speed drive for each determined operating point.

[0223] Estimated current The stator resistance is based on the electric motor representation model. Leakage inductance resistivity Inductance The estimated current is calculated based on the initial estimate and the electrical command applied to the motor to reach the operating point. The estimated operating parameter Ope corresponds to the operating point associated with example method 200.

[0224] As shown in block 240, example method 200 includes calculating the current difference Δi by the variable speed drive for each determined operating point. dq Current difference Δi dq Corresponding to the estimated current of the motor at the operating point The actual current I measured at the operating point of the motor dq The difference between Current difference Δi dq This corresponds to the operation difference Opd associated with the operation point of example method 200.

[0225] As shown in block 250, example method 200 includes the variable speed drive operating at each determined operating point based on the current difference Δi. dq The third and fourth equations determine the operational coefficients Q and q. Rs ,q Lf ,q L ,R,r Rs ,r Lf ,r Rreq Therefore, at each operating point, the value of the operating coefficient is estimated based on the motor's representation model and the operating difference Opd.

[0226] At this point, the transmission drive has determined the operating coefficient set for each operating point. In some examples, the operating coefficient set for the first operating point could be (Q1, q1...). Rs ,q1 Lf ,q1 L ,R1,r1Rs ,r1 Lf and r1 Rreq And the set of operation coefficients for the second operation point can be (Q2, q2) Rs ,q2 Lf ,q2 L ,R2,r2 Rs r2 Lf and r2 Rreq Therefore, the variable speed drive obtains a system with four equations:

[0227] 1)

[0228] 2)

[0229] 3)

[0230] 4)

[0231] The arrow in method 200 connecting block 250 to block 210 illustrates the fact that the transmission drive runs blocks 210-250 twice, once for each of the two operating points, to obtain four equations.

[0232] As shown in block 260, example method 200 includes determining the stator resistance by the variable speed drive. Leakage inductance Inductance and specific resistance Detailed estimates of motor parameters. It is determined based on the set of operating coefficients at each operating point and the third and fourth equations. By solving the above system based on the operating coefficients and the representation model, the variable speed drive can determine the stator resistance. Leakage inductance Inductance and specific resistance The refined estimates. In some examples, a matrix can be used to determine the refined estimates of the motor parameters:

[0233]

[0234] Where w corresponds to

[0235] x corresponds to

[0236] y corresponds to and,

[0237] z corresponds to

[0238] Therefore, the variable speed drive can reduce the stator resistance Leakage inductance Inductance and specific resistance The refined estimate is determined to be equal to the stator resistance R. s Leakage inductance L f Specific inductance L and specific resistance R req The actual value is determined, for example, by matrix inversion and by calculating w, x, and y.

[0239] Example method 200's representation model of the electric motor requires two operating points to determine the stator resistance. Leakage inductance Inductance and specific resistance The refined estimate may be obtained from more than two operation points, such as n operation points (n>2), and the four values ​​to be determined are obtained. A system with 2n equations. In other words, to determine the stator resistance... Leakage inductance Inductance and specific resistance For the refined estimates, example method 200 requires at least two operation points. As presented above for example method 100, in the case of 2n equations for four refined estimates, the transmission drive can determine the refined estimates based on a recursive least squares algorithm or a linear regression model.

[0240] As shown in block 270, example method 200 includes a variable speed drive based on stator resistance. Leakage inductance Inductance and specific resistance The refined estimates determine the four values ​​of the VSD parameter set Svp3. This block is as follows: Figure 5d As shown. Detailed estimates of the leakage inductance of the motor parameters. Allows direct determination of the leakage inductance L of this group of VSD parameters. f Detailed estimate of stator resistance in motor parameters. Allows direct determination of the stator resistance R of the VSD parameter set s Detailed estimates of the specific inductance of the motor parameters. Allows indirect determination of the no-load current I of VSD parameter group Svp3 v Compared to inductance and specific resistance The refined estimate allows for the indirect determination of the rotor time constant T. rExample method 200 allows for improved control of a motor using a variable speed drive by determining the values ​​of the VSD parameter set in the closed loop. The values ​​of this VSD parameter set are determined based on refined estimates of the motor's electrical parameters.

[0241] We have just shown two examples that allow the determination of the VSD parameter set using the electrical parameters of the motor, but we can do a similar determination using mechanical parameters. This is the goal of example method 300 below.

[0242] Example method 300:

[0243] refer to Figure 6 Example method 300 is presented.

[0244] One of the goals of Example Method 300 is to determine the VSD parameter set Svp4, which includes two VSD parameters, based on refined estimates of at least two motor parameters of the representation model of Example Method 300. These two VSD parameters include the motor inertia J and the load torque τ. L Example method 300's VSD parameter group Svp4 example is in Figure 7a As shown in the image.

[0245] The first equation that allows determining the representation model of example method 300 of the VSD parameter set Svp4 is:

[0246]

[0247] in:

[0248] It is an initial estimate of the motor inertia of the electric motor and can be expressed in kilogram-meter square (kg·m²). 2 (This indicates that motor inertia is a motor parameter.)

[0249] It is the operating coefficient and corresponds to the acceleration of the motor. Acceleration can be expressed in meters per second squared (ms). -2 )express.

[0250] τ em This is the operating factor and corresponds to the electromagnetic torque of the electric motor. Electromagnetic torque can be expressed in Newton-meters (Nm).

[0251] It is the load torque τ of the electric motor L The initial estimate. The load torque can be expressed in Newton-meters (Nm).

[0252] In some examples, motor inertia may include rotor inertia. In some examples, motor inertia is the sum of the different inertias in the motor.

[0253] The load torque τ of the electric motor L It can be equal to:

[0254] τ L =K0, or

[0255] τ L =K0+K1ω r ,or

[0256] τ L =K0+K1ω r +…+K m ω r m ,

[0257] in:

[0258] K0,K1,…,K m Here, represents the load torque parameter and the corresponding motor parameter, where m is a natural integer.

[0259] ω r This corresponds to the rotor speed of the motor at the operating point.

[0260] Figure 7b An example of a motor parameter group Smp4 illustrating example method 300 of this embodiment is presented.

[0261] For the purposes of exemplifying method 300, a load torque τ equal to the load torque parameter K0 can be selected. L . Figure 7c An example of motor parameter group Smp5 illustrating example method 300 of this embodiment is presented.

[0262] Therefore, the second equation that allows the representation model of example method 300, which determines the VSD parameter set Svp4, is:

[0263]

[0264] In example method 300, the objective is to determine a refined estimate of the motor inertia. Detailed estimates of motor parameters

[0265] As shown in block 310, method 300 includes applying an electrical command to a motor via a speed changer, causing the motor to operate successively at two different operating points.

[0266] As shown in block 320, example method 300 includes determining the actual acceleration of the motor by the speed drive for each determined operating point based on measurements taken by the speed drive at the operating point. and actual electromagnetic torque τ em Actual acceleration and actual electromagnetic torque τ em Both allow for the determination of the actual operating parameters Opr of example method 300. In this case, the actual operating parameters Opr include an actual vector that includes the actual acceleration. and actual electromagnetic torque τ em In some examples, the value of the actual operation parameter Opr can be the norm of the actual vector.

[0267] As shown in block 330, example method 300 includes the variable speed drive, based on motor inertia, for each determined operating point. and load torque parameters The estimated acceleration of the motor is determined by the initial estimate, the second equation of example method 300, and the electrical command applied to the motor to reach a determined operating point. And estimating electromagnetic torque Estimated acceleration And estimating electromagnetic torque Both methods allow determining the estimated operating parameter Ope of example method 300. In this case, the estimated operating parameter Ope includes an estimated vector that comprises the estimated acceleration and the estimated electromagnetic torque. In some examples, the value of the estimated operating parameter Ope can be the norm or magnitude of the estimated vector.

[0268] As shown in block 340, example method 300 includes calculating an operating difference Opd by a variable speed drive for each determined operating point based on the actual operating parameter Opr and the estimated operating parameter Ope. Here, the operating difference may correspond to the distance between the value of the estimated operating parameter Ope in the motor at the operating point and the value of the actual operating parameter Opr obtained based on measurements from the variable speed drive at the operating point. In some examples, the operating difference Opd may correspond to the norm of the estimated vector or the difference between the magnitude and the norm of the real vector. The operating difference Opd of example method 300 is associated with the operating point.

[0269] As shown in block 350, example method 300 includes determining the operating coefficient OC by the variable speed drive for each determined operating point based on the operating difference Opd and a representation model of the motor. J and OC K0 The value of . Figure 7d An example of a representation model P of the electric motor for example method 300 is shown, which includes the operating coefficient OC. J and OC K0 .

[0270] At this point, the transmission drive has determined the operating coefficient set for each operating point. In some examples, the operating coefficient set for the first operating point could be (OC1). J ,OC1 K0And the operation coefficient group for the second operation point can be (OC2) J OC2 K0 Therefore, the variable speed drive has determined two values ​​that need to be determined, which can be determined by the variable speed drive itself (motor inertia). and load torque parameters The system of two equations (the refined estimate of the value).

[0271] The arrow connecting block 350 to block 310 in method 300 illustrates the fact that the transmission drive runs blocks 310-350 twice, once for each of the two operating points, to obtain two equations. For the previous example method, example method 300 could include more than two operating points, such as n operating points, where n is a natural integer greater than two (n>2), to obtain n equations with two determined refinement estimates. In this case, example method 300 could use a linear regression model as a recursive least squares algorithm to determine the refinement estimates.

[0272] As shown in block 360, example method 300 includes determining the motor inertia by the variable speed drive. and load torque parameters Detailed estimates of motor parameters. and The value is determined based on the set of operating coefficients and the motor representation model at each operating point.

[0273] As shown in block 370, example method 300 includes a variable speed drive based on motor inertia. and load torque parameters The refined estimates determine two values ​​for the VSD parameter set Svp4. This block is as follows: Figure 7e As shown. Detailed estimates of motor inertia for motor parameters. This allows for the direct determination of the motor inertia J of the VSD parameter group. Detailed estimates of the load torque parameters are also provided. Allows for indirect determination of the motor load torque τ of VSD parameter group Svp4. L .

[0274] It should be noted that the load torque τ L It can include several load torque parameters K0, K1, K2, ..., K m (Corresponding to m+1 motor parameters, where m is a natural integer), this means that example method 300 may include at least m+2 operating points to determine the motor inertia J and load torque τ of the VSD parameter Svp4 group according to the second equation. L .

[0275] Example method 300 allows for improved control of a motor using a variable speed drive by determining the values ​​of a set of VSD parameters. The values ​​of this VSD parameter set are determined based on refined estimates of the motor's mechanical parameters.

[0276] The three example methods described above all involve blocks of the same type, with variations depending on the chosen motor representation model. In fact, the example methods can be found in the reference below. Figure 8 The same general approach 400 is presented to integrate or summarize.

[0277] Method 400:

[0278] Method 400 is a method for controlling a motor using a variable speed drive. The variable speed drive can store a representation model of the motor. The representation model of the motor can include motor parameters in the motor parameter group Smp. One or more initial estimates. An example of the motor parameter group Smp is shown in... Figure 9a The motor parameters are shown and included. and Two initial estimates.

[0279] Motor parameters can be considered constant values ​​during the execution of the method proposed herein. Motor parameters are inherent parameters of the electric motor. The values ​​of the motor parameters can be independent of the motor's operating point or independent of the electrical commands applied to the motor. That is, the motor parameters can be considered constant for two different operating points of the motor or for two different electrical commands applied to the motor.

[0280] The electrical parameter set may include electrical parameters, mechanical parameters, or a combination of electrical and mechanical parameters as shown above.

[0281] In some examples, electrical parameters may include:

[0282] Stator inductance L of the motor s ,

[0283] The rotor inductance L of the electric motor r ,

[0284] mutual inductance L of the electric motor m ,

[0285] Stator resistance R of the electric motor s ,

[0286] Rotor resistance R of the electric motor r ,

[0287] The specific inductance L of the electric motor

[0288] Leakage inductance L of the motor f ,

[0289] The specific resistance R of the electric motor req .

[0290] Different inductances can be represented by Henry (H). Different resistances can be represented by Ohm (Ω).

[0291] In some examples, mechanical parameters may include:

[0292] The motor inertia J of the electric motor can be expressed in kilogram-meter square (kg·m²). 2 )express,

[0293] The load torque τ of the electric motor L Load parameters K0, K1, ... K m The load torque can be expressed in Newtons (Nm).

[0294] A representation model of a motor can be established based on a default set of parameters for the motor. In this disclosure, establishing a representation model should be understood as meaning that initial estimates of the motor parameters of the representation model can be estimated based on the default set of parameters in the initial stage. In other words, initial estimates of the motor parameters of the motor parameter set can be initialized based on the default set of parameters for the motor. This default set of parameters may include the nameplate values ​​of the motor. In some examples, this default set of parameters may include one or more of nominal voltage, nominal current, nominal frequency, nominal speed, power factor, nominal power, or full-load speed. As mentioned above, one of the goals of the method proposed herein is to determine refined estimates of the motor parameters of the representation model and use them to determine the VSD parameter set in order to improve the control of the motor via a variable speed drive. In this case, initializing the initial estimates of the motor parameters based on the default set of parameters can improve the determination accuracy of the VSD parameters using fewer operating points, because the initial estimates of the motor parameters (in this case, the default parameters) will, for example, be closer to the refined estimates determined by these methods than random parameter values.

[0295] As shown in block 410, method 400 may include applying one or more electrical commands to a motor via a variable speed drive, causing the motor to operate at one or more defined operating points.

[0296] As we understand from the example methods above, the number of operating points depends on the representation model of the motor. In some examples, in a representation model that includes two motor parameters and an equation, method 400 may include applying two different electrical commands to achieve two different determined operating points to determine refined estimates of the two motor parameters.

[0297] As shown in block 420, method 400 may include determining the actual operating parameter Opr in the motor based on measurements taken by the variable speed drive at each determined operating point.

[0298] Actual operating parameters

[0299] The actual operating parameter Opr is a parameter connected to the estimated operating parameter Ope.

[0300] The actual operating parameter Opr at a given operating point depends on the actual values ​​of the motor parameters mp and the given operating point. The actual operating parameter Opr at a given operating point can be estimated based on measurements taken by the variable speed drive at that point.

[0301] The actual operating parameter Opr represents the actual response of the motor at a given operating point.

[0302] In some examples, the values ​​representing the actual operating parameters of the model can be determined based on the actual current I of the motor, which corresponds to the current of the motor at the operating point and is determined by the transmission drive based on measurements of the current in the motor. In some examples, the actual current I can be the actual current I in the Park coordinate system. dq The corresponding vector.

[0303] In some examples, the values ​​representing the actual operating parameters of the model can be based on the motor's rotor speed ω, which corresponds to the motor's speed at the operating point. r Determine the rotor speed ω r The speed is determined by the variable speed drive based on the angular position of the motor at the operating point.

[0304] In some examples, the values ​​representing the actual operating parameters of the model can be based on the actual electromagnetic torque τ of the motor. em Determine the actual electromagnetic torque τ of the electric motor. em It corresponds to the electromagnetic torque of the motor at the operating point, which is determined by the variable speed drive based on the measurement value of the variable speed drive at the operating point.

[0305] In some examples, it can be based on the acceleration of the motor at the operating point. To estimate the values ​​of actual operating parameters, this can be based on the rotor speed ω of the motor at the operating point. r Acceleration is determined by measurements.

[0306] In some examples, the actual operating parameter Opr can be an actual vector (such as a VSD-based measurement or a determined value), comprising several actual values ​​of the motor depending on the operating point. In some examples, the value of the actual operating parameter Opr can be the norm or magnitude of an actual vector, which comprises several actual values ​​of the motor at the operating point.

[0307] As shown in block 430, method 400 may include determining estimated operating parameters in the motor by the variable speed drive for each determined operating point based on estimates of motor parameters of a representation model of the motor and electrical commands associated with the operating point.

[0308] Estimated operating parameters

[0309] The estimated operating parameter Ope depends on the electrical command applied to the motor to reach the operating point and the initial estimates of the motor parameters representing the model. The estimated operating parameter Ope represents the theoretical response of the motor at a given operating point.

[0310] As mentioned above, the estimated operating parameter Ope is a parameter associated with the actual operating parameter Opr. Here, "connection" should be understood as the estimated operating parameter Ope and the actual operating parameter including values ​​of the same type or representing the same physical size.

[0311] In some examples, the estimated operating parameters can be an estimation vector comprising several estimated values, such as the estimated rotor speed determined for the operating point. Estimated current Estimating electromagnetic torque and estimated acceleration In some examples, the current is estimated. This could be the estimated current corresponding to the Park coordinate system. The vector.

[0312] In some examples, the estimated value of the operating parameter Ope can be the norm or magnitude of an estimation vector that includes several estimates of the motor parameters determined for the operating point.

[0313] As shown in block 440, method 400 may include calculating the operation difference Opd for each determined operation point based on the actual operation parameter Opr and the estimated operation parameter Ope.

[0314] Poor operation

[0315] The operating difference Opd is the difference between the estimated operating parameters and the actual operating parameters at a given operating point (Opd = OpeOpr). Therefore, the operating difference can characterize the initial estimate of the motor parameter set Smp representing the model. The difference between the actual value of the motor parameters (mp) and the actual value of the motor parameters. Therefore, it represents the initial estimate of the motor parameters for the model. The more accurate (i.e., closer to the actual value mp), the lower the absolute value of the operational error.

[0316] Therefore, a refined estimate of the motor parameters can be found by minimizing the operating difference Opd at different operating points of the motor. Minimizing the operational error involves modifying the initial estimates of the motor parameters in the motor parameter set.

[0317] When the estimated operating parameter Ope and the actual operating parameter Opr are the estimated vector and the actual vector, respectively, the operating difference can be the distance between the estimated vector and the actual vector. In some examples, the operating difference can be the difference between the norm or magnitude of the estimated vector and the real vector.

[0318] As shown in block 450, method 400 may include determining the value of at least one operating coefficient by the variable speed drive for each determined operating point, based on the operating difference Opd and a representation model of the motor. The number of operating coefficients depends on the number of motor parameters in the representation model and the number of equations in the representation model.

[0319] Operation coefficient

[0320] The operating coefficient can be associated with the motor parameters and / or operating point representing the model. The operating coefficient Oc can represent the initial estimate of the motor parameters. The connection between the actual values ​​of the motor parameters in the model and the actual values ​​of the motor parameters. Figure 9b The example illustrating this relationship is provided. The estimated value of motor parameter mp1. The actual value mp1 is connected to the operating coefficient Oc1, while the estimated value of the motor parameter mp2 is... The actual value mp2 is connected to the operating coefficient Oc2, as shown by the arrow.

[0321] The value of the operating coefficient Oc depends on the operating point of the motor and the representation model. It can be determined based on initial estimates of the motor parameters at a specific operating point. The value of each operating coefficient Oc is estimated by estimating the operating parameter Ope and the actual operating parameter Opr.

[0322] The arrow in method 400 connecting block 450 to block 410 illustrates the fact that the transmission drive runs through blocks 410-450 at least once to determine at least one operating coefficient associated with each of at least one determined operating point.

[0323] As shown in block 460, method 400 may include a refined estimate of at least one motor parameter of a representation model determined by the transmission drive based on at least one operating coefficient Oc determined at each operating point and based on the representation model. The at least one motor parameter corresponds to a motor parameter connected to the at least one operating coefficient. As shown in the example method above, the at least one motor parameter also depends on the representation model of the motor. The refined estimate may be determined, for example, based on a solution system or may be based on a linear regression model as a recursive least squares algorithm.

[0324] As shown in block 470, method 400 may include determining the value of a VSD parameter set by the variable speed drive based on a refined estimate of at least one motor parameter, the VSD parameter set including at least two VSD parameters.

[0325] VSD parameters:

[0326] In this disclosure, VSD parameters should be understood as input parameters used to control the variable speed drive of the electric motor. VSD parameters correspond to the parameters of the electric motor. In some examples, VSD parameters may include electrical or mechanical parameters.

[0327] Determining a precise set of VSD parameters can improve the variable speed drive's control of the motor.

[0328] In some examples, the VSD parameter group may include the stator resistance R. s No-load current I v Leakage inductance L f Rotor time constant T r , load torque τ L And the motor inertia J of the electric motor.

[0329] As mentioned above, the values ​​of this VSD parameter group can be determined directly or indirectly based on the motor parameters representing the model.

[0330] Here, "directly determined" means that the value of the VSD parameter is directly equal to the refined estimate of the motor parameters representing the motor parameter group Smp of the model. "Indirectly determined" means that the value of the VSD parameter can be determined based on the refined estimate of the motor parameters.

[0331] Detailed estimates based on motor parameters and An example of the obtained VSD parameter group is as follows: Figure 9c As shown. The VSD parameter VSD1 is obtained directly based on the actual value of motor parameter mp1. The VSD parameter is obtained indirectly based on the actual values ​​of motor parameters mp1 and mp2.

[0332] The determined VSD parameter set may include the stator resistance R s No-load current Iv Leakage inductance L f Rotor time constant T r , load torque τ L At least two of the following: the inertia of the motor J.

[0333] Method 400 allows for real-time calculation of a set of VSD parameters applicable to each motor. This set of VSD parameters serves as input to the variable speed drive controlling the motor, adaptively improving motor control because the VSD parameters are determined based on refined estimates of the motor parameters for each motor.

[0334] Method 400 may further include updating the representation model of the motor based on refined estimates of at least one determined motor parameter. In this disclosure, updating the motor representation model should be understood as replacing the initial estimates of at least one motor parameter in the representation model with the determined refined estimates associated with at least one motor parameter. This allows for real-time improvement of the motor representation model. Therefore, in each iteration of the method, the control of the motor via the variable speed drive is improved throughout the motor's lifespan.

[0335] It is important to note that, for the purposes of the new iteration of Method 400, the refined estimates of the motor parameters, instead of the initial estimates representing the motor parameters in the model, become the initial estimates representing the motor parameters in the model. This initial estimate (the previous refined estimate from the previous iteration) will be closer to the new refined estimate determined by the new iteration of Method 400.

[0336] Method 400 may also include:

[0337] When the distance between at least one operating coefficient and at least one previously stored operating coefficient is higher than a determined threshold, the value of at least one operating coefficient is stored in the transmission drive.

[0338] Method 400 allows for the determination of refined estimates of motor parameters for a representation model of the motor by obtaining an equation representing the difference between the theoretical and actual responses of the motor for different operating points. Therefore, determining operating coefficients appended to one operating point that are close to previously stored operating coefficients appended to another operating point implies having two similar equations, which would make the determination of refined estimates of motor parameters less accurate.

[0339] Then, when the distance is above a predetermined threshold, the value of at least one operating coefficient can be used to determine a refined estimate of the motor parameters representing the model, and can be stored in the transmission drive along with the determined operating point. In some examples, when the distance is below the predetermined threshold, the value of at least one operating coefficient is not used when determining the refined estimate of the motor parameters, and the electrical commands can be modified to achieve another determined operating point.

[0340] Method 400 may also include suggesting operating points to the operator of the motor to determine the VSD parameter set by performing method 400. In some examples, method 400 may suggest that the operator select electrical commands to reach a determined first operating point at low speed and full load, and a second operating point at high speed and low load.

[0341] Method 400 may also include, prior to block 450, a block 445 that determines performance values ​​representing the model. In this disclosure, parameter values ​​should be understood as values ​​characterizing the motor's performance based on initial estimates of electrical commands and motor parameters. Performance values ​​may be expressed as percentages. In some examples, performance values ​​may be determined based on the absolute value of the operating difference (|Opd|) at the operating point characterizing motor parameter errors and the value of the electrical command.

[0342] In some examples, method 400 may include continuing to execute method 400 when the performance value is below a predetermined threshold expressed as a percentage. In some examples, the determined threshold may be between 80% and 95% and may preferably be equal to 90%. In some examples, when the performance value is above the determined threshold, method 400 may include stopping its execution, and in some cases, warning the operator that the control of the motor via the variable speed drive is as precise as desired.

[0343] Method 400 may further include controlling the motor based on a stored VSD parameter set. This stored VSD parameter set may be stored in the memory of the variable speed drive. The stored VSD parameter set may be updated at each iteration of method 400 based on a determined VSD parameter set including at least two VSD parameters, in order to refine the stored VSD parameter set at each iteration.

[0344] Motors can also be assigned a type. This type can include, for example, the motor's range, year of manufacture, and production location. Therefore, method 400 can include storing a motor dataset that includes the determined VSD parameter set, the motor type, and the motor's operating time. Operating time can be expressed in operating hours. In some examples, statistics about multiple motors can be collected based on each motor type and its operating time.

[0345] This disclosure also proposes a method for processing data on electric motors, wherein the data includes multiple electric motor datasets. Each dataset may be associated with an electric motor and includes the type of electric motor, a set of VSD parameters for the electric motor, and the operating time of the electric motor. When method 400 is performed on multiple electric motors, multiple datasets may be obtained according to embodiments of method 400.

[0346] Methods for processing motor data may include:

[0347] Motors are classified based on the evolution of their VSD parameter sets during operation; and / or

[0348] For a specific type of motor, based on several datasets including motors of that specific type, a predicted set of VSD parameters is determined for a given running time.

[0349] Classifying motors based on the evolution of their VSD parameter sets over time can, for example, allow the identification of some production lines that are less efficient than others in relation to the evolution of the motor's VSD parameters, and thus identify potential problems in such production lines.

[0350] Determining the predicted VSD parameter set within a defined operating time can, for example, allow for setting an accurate VSD parameter set for a motor driven by a variable speed drive that may not be compatible with the methods presented herein. In this case, the accurate VSD parameters can be set directly for the motor based on its specific type and operating time.

Claims

1. A method for controlling an electric motor using a variable speed drive, the method comprising: - Apply one or more electrical commands to the motor via a variable speed drive, causing the motor to operate at one or more defined operating points; - For each defined operating point, the actual operating parameters in the motor are determined by the transmission drive based on the measurements taken by the transmission drive at the operating point. The actual operating parameters include at least one of the motor's current, torque, speed, and acceleration. - For each defined operating point, estimated operating parameters in the motor are determined by initial estimates of motor parameters from a motor representation model based on the variable speed drive and electrical commands associated with the operating point, wherein the estimated operating parameters represent the theoretical response of the motor at the defined operating point, and the representation model includes one or more equations representing the difference between the initial estimates of one or more motor parameters and the actual values ​​of one or more motor parameters at the motor operating point, and one or more equations allowing the determination of the theoretical response of the motor at the operating point based on the initial estimates of one or more parameters, and the motor parameters are constant, inherent parameters of the motor and include both electrical and mechanical parameters; - For each defined operating point, calculate the operating difference based on the actual operating parameters and the estimated operating parameters. - For each given operating point, the value of at least one operating coefficient is determined by the variable speed drive based on the operating difference and the motor representation model, wherein the operating coefficient represents the difference between the estimated value of the motor parameters and the actual value of the motor parameters at the operating point; - By using a variable speed drive, a refined estimate of at least one motor parameter of the representation model is determined based on at least one operating coefficient and the representation model determined at each operating point; - The value of the VSD parameter set is determined by the variable speed drive based on a refined estimate of at least one motor parameter, the VSD parameter set including at least two VSD parameters.

2. The method according to claim 1, wherein, The representation model is established based on the default parameter set of the electric motor.

3. The method according to claim 2, wherein, The default parameter group includes the nameplate parameters of the motor.

4. The method according to claim 1, wherein, The method further includes: - Update the representation model based on the refined estimates of at least one determined motor parameter.

5. The method according to claim 1, wherein, The method further includes: - When the distance between at least one operating coefficient and at least one previously stored operating coefficient is higher than a determined threshold, the value of the at least one operating coefficient is stored in the transmission drive.

6. The method according to claim 1, wherein, The estimated operating parameters and the actual operating parameters are respectively an estimated vector and an actual vector, each comprising several values, and the operating difference corresponds to the difference between the norms of the estimated vector and the actual vector.

7. The method according to claim 1, further comprising determining the performance value of the representation model based on the value of the electrical command and the operational difference determined at the operating point.

8. The method according to claim 1, wherein the method includes continuing to execute the method when the performance value is lower than a determined threshold.

9. The method according to claim 1, further comprising controlling the motor via a variable speed drive based on a stored VSD parameter set.

10. The method according to claim 1, wherein, The VSD parameter set includes at least two of the following: stator resistance, no-load current, leakage inductance, rotor time constant, load torque, and motor inertia.

11. The method according to claim 1, wherein, The method further includes assigning a type to the motor, and storing a motor dataset in a remote server, the motor dataset including a determined VSD parameter set, the motor type, and the motor's operating time.

12. A method for processing electric motor data, wherein, The data includes multiple motor datasets, each associated with a motor and including the motor type, the motor's VSD parameter set, and the motor's operating time. The multiple motor datasets are obtained according to the method of claim 11, the method comprising: - Classify motors based on the evolution of their VSD parameter sets during operation; and / or - Based on several datasets including specific types of motors, determine the predicted VSD parameter set for a specific type of motor at a given running time.

13. A computer-readable storage medium comprising instructions that, when executed by a processor (PROC), cause the processor to perform the method according to any one of the preceding method claims.

14. A variable speed drive, comprising a processor adapted to control an electric motor according to any one of the preceding claims.

Images