Device and method for determining motor characteristic parameters, supply chain and computer program

Abstract

An electronic determination device (20) is configured for determining at least one characteristic parameter of an electrical machine (12) having P phases (22), P > 3, connected to an electrical starter (14) comprising at least P-1 switching arms (24), each switching arm (24) being connected to a respective phase (22) of the electrical machine (12). The determination device (20) comprises a control module (30) configured to control a respective switching arm (24) to be closed and other switching arm(s) (24) to be opened so as to generate a current injection on two phases (22) of the electrical machine (12), an acquisition module (34) configured to acquire, after the generation of the current injection, a measurement of a respective current(s) and voltage(s) of said two phases (22), and a calculation module (36) configured to calculate the at least one characteristic parameter of the electrical machine (12) from the measurement of the respective current(s) and voltage(s).

Description

Technical Field

[0001] The present invention relates to an electronic determining device for determining at least one characteristic parameter of a motor connected to an electric starter.

[0002] The present invention also relates to a power supply chain for an electric motor, the power supply chain including an electric starter adapted to be connected between an AC power source and the motor, and an electronic determining device for determining at least one characteristic parameter of the motor.

[0003] The present invention also relates to a method for determining at least one characteristic parameter of a motor connected to an electric starter, the method being implemented by such an electronic determining device.

[0004] The present invention also relates to a computer program comprising software instructions that implement such a determining method when executed by a processor. Background Technology

[0005] This invention relates to the evaluation of (multiple) characteristic parameters of motors, particularly electric motors.

[0006] Currently, variable speed drives can be used to evaluate (multiple) characteristic parameters of a motor, and thanks to pulse width modulation technology and power electronic switches, variable speed drives can generate any voltage waveform.

[0007] These (multiple) characteristic parameters then allow for the estimation of mechanical torque and mechanical speed. For example, they allow for the estimation of motor losses, which are important for the quality and performance of torque estimation, and then torque control.

[0008] With an electric starter, the voltage waveform is completely confined to a portion of the mains supply. Currently, electric starters cannot fully recognize (multiple) machine parameters.

[0009] Currently, an electric starter is used, so the losses are roughly adjusted by the user.

[0010] However, it is difficult to know how much loss value should be entered because it depends on the motor. In addition, the loss value is also affected by the resistance of the cable connected between the electric starter and the motor. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide an electronic determination device and related method for determining at least one characteristic parameter of a motor connected to an electric starter, which allows for easier and more accurate determination of said characteristic parameter(s).

[0012] Therefore, the subject of this invention is an electronic determining device for determining at least one characteristic parameter of a motor connected to an electric starter, the motor having P phases, where P is an integer greater than or equal to 3, the electric starter being adapted to be connected to an AC power source, and comprising at least P-1 switching arms, each switching arm being connected to a corresponding phase of the motor.

[0013] The determining device includes:

[0014] - A control module configured to control the closing of corresponding(multiple) switch arms and the opening of other(multiple) switch arms to generate current injection on two phases of the motor;

[0015] - An acquisition module configured to acquire measurements of corresponding current(s) and voltage(s) of the two phases after current injection; and

[0016] - A calculation module configured to calculate at least one characteristic parameter of the motor based on the measurements of the respective current(s) and voltage(s).

[0017] Therefore, the determining device according to the invention allows the use of the starter's switching arm to generate current injection in a stationary motor. In practice, the machine is stationary because the control module controls the opening of at least one phase(s) of the switching arm(s). Current injection is generated on the other two phases of the motor. The calculation module then calculates at least one characteristic parameter of the motor in a convenient and accurate manner based on the corresponding current(s) and voltage(s) measurements of the other two phases.

[0018] According to other advantageous aspects of the invention, the electronic determining device includes one or more of the following features, which are employed individually or in any technically possible combination:

[0019] - Each feature parameter is selected from a group that includes the following:

[0020] • Stator resistance of the motor;

[0021] • Rotor resistance of the motor;

[0022] • The leakage inductance of the motor; and

[0023] • The main inductance of the motor;

[0024] -The control module is configured to, after the current injection occurs at the initial moment, control the corresponding previously closed (multiple) switch arms to open at the end moment in order to cut off the current injection;

[0025] The duration of current injection between the initial and final moments is preferably a predefined time period;

[0026] The predefined time period is preferably greater than five times the rotor time constant;

[0027] - The calculation module is configured to calculate the stator voltage of the motor stator based on the voltage measurement values ​​of the two phases and the stator current based on the current measurement values ​​of the two phases, and the calculation module is further configured to calculate at least one characteristic parameter of the motor based on the stator voltage value and the stator current value;

[0028] - The calculation module is configured to calculate the corresponding stator voltage and stator current values ​​based on the transformations applied to the corresponding voltage and current measurements of the two phases;

[0029] The calculation module is preferably configured to calculate the corresponding stator voltage and stator current values ​​according to the following equations:

[0030]

[0031] I S =I1=-I2

[0032] Among them U s Indicates stator voltage.

[0033] U1 and U2 represent the voltages in the first and second phases, respectively;

[0034] I s Represents stator current, and

[0035] I1 and I2 represent the current in the first phase and the current in the second phase, respectively;

[0036] - The calculation module is configured to calculate the total resistance of the motor based on the stator current and stator voltage at the moment corresponding to the maximum value of the stator current after current injection. The total resistance is equal to the sum of the stator resistance and the rotor resistance of the motor.

[0037] The calculation module is preferably configured to calculate the total resistance according to the following equation:

[0038]

[0039] Where R t o t Indicates the total resistance.

[0040] Us represents the stator voltage.

[0041] I s Represents stator current, and

[0042] t0 represents the moment corresponding to the maximum value of the stator current;

[0043] - The calculation module is configured to calculate the motor's leakage inductance based on the time derivative of the stator current and the stator voltage after current injection is generated;

[0044] The calculation module is preferably configured to calculate the leakage inductance according to the following equation:

[0045]

[0046] Where L f Indicates leakage inductance.

[0047] U s Represents stator voltage, and

[0048] I s Stator current;

[0049] - The calculation module is configured to calculate the stator resistance of the motor based on the integral of the stator voltage and the integral of the stator current during the duration of current injection;

[0050] The calculation module is preferably configured to calculate the stator resistance according to the following equation:

[0051]

[0052] Where Rs represents the stator resistance.

[0053] U s Indicates stator voltage.

[0054] I s Represents stator current.

[0055] t init Indicates the initial time of the measurement during current injection.

[0056] t end Indicates the end time of the measurement, and

[0057] T represents the duration of the measurement;

[0058] - The calculation module is configured to calculate the motor's main inductance based on the motor's leakage inductance, stator current, and the integral of the stator flux during the duration of current injection.

[0059] The calculation module is preferably configured to calculate the main inductance according to the following equation:

[0060]

[0061] Where L represents the main inductance.

[0062] L f Indicates leakage inductance.

[0063] Is Represents stator current, and

[0064] This represents the integral of the stator flux during the duration of the current injection.

[0065] Preferred is defined according to the following equation:

[0066]

[0067] R s Indicates stator resistance.

[0068] U s Indicates stator voltage.

[0069] I s Represents stator current.

[0070] t init This indicates the initial moment of current injection.

[0071] t end This indicates the end time of current injection, and

[0072] T represents the duration of the current injection;

[0073] -P equals 3;

[0074] The determining device is configured to determine corresponding characteristic parameters of the motor in at least two consecutive sequences, and

[0075] During each sequence, the control module is configured to control the closing of corresponding(multiple) switch arms and the opening of other switch arms to generate current injection on two phases of the motor; the acquisition module is configured to acquire measured values ​​of corresponding(multiple) current(multiple) voltage(s) of the two phases after the current injection; and the calculation module is configured to calculate characteristic parameters of the motor based on the corresponding(multiple) current(multiple) voltage(s) measured values ​​of the corresponding sequence.

[0076] The open switch arms change from one sequence to another, such that each of at least two switch arms is opened once during the consecutive sequence;

[0077] The determining device further includes a diagnostic module configured to compare at least two values ​​determined for a corresponding feature parameter in a continuous sequence and generate an alarm signal if the deviation between the at least two determined values ​​exceeds a predefined threshold.

[0078] The subject of this invention is also a power supply chain for an electric motor having P phases, where P is an integer greater than or equal to 3, and the power supply chain includes:

[0079] - An electric starter suitable for connection between an AC power source and a motor, said electric starter comprising at least P-1 switching arms, each switching arm adapted to connect to a corresponding phase of the motor.

[0080] - An electronic determining device for determining at least one characteristic parameter of a motor, the electronic determining device being described above.

[0081] The subject of this invention is also a method for determining at least one characteristic parameter of a motor connected to an electric starter, the motor having P phases, where P is an integer greater than or equal to 3, the electric starter being adapted to be connected to an AC power source and comprising at least P-1 switching arms, each switching arm being connected to a corresponding phase of the motor.

[0082] The method is implemented by an electronic determination device and includes the following steps:

[0083] - Control the closing of corresponding (multiple) switch arms and the opening of other (multiple) switch arms to generate current injection on two phases of the motor;

[0084] - After current injection is generated, measurements of the corresponding current(s) and voltage(s) of the two phases are acquired; and

[0085] - Calculate at least one characteristic parameter of the motor based on the measured values ​​of the corresponding current(s) and voltage(s).

[0086] The subject of this invention is also a computer program, including software instructions that implement the methods described above when executed by a processor. Attached Figure Description

[0087] The invention will be better understood by reading the following description, which is given by way of example only and with reference to the accompanying drawings, in which:

[0088] Figure 1 This is a schematic representation of a power supply chain for an electric motor according to a first embodiment, the power supply chain including an electric starter adapted to be connected between an AC power source and an electric motor, and an electronic determining device for determining at least one characteristic parameter of the electric motor.

[0089] Figure 2 This is a view showing the voltage and current curves during continuous current injection in the motor, the injection being via... Figure 1 The electric starter in the middle is controlled by a determining device;

[0090] Figure 3 This is a flowchart of a method for determining at least one characteristic parameter of a motor according to the first embodiment, the method comprising: Figure 1 The determining device is implemented;

[0091] Figure 4 It is based on the second embodiment and Figure 1 Similar views; and

[0092] Figure 5 It is related to the second embodiment. Figure 3 A similar view. Detailed Implementation

[0093] exist Figure 1 In the motor 12, the power supply 10 includes an electric starter 14 connected between the AC power source 16 and the motor 12, and an electronic determining device 20 for determining at least one characteristic parameter, such as the stator resistance R. s Equivalent rotor resistance R req The leakage inductance Lf or main inductance L of motor 12.

[0094] Motor 12 has P phases 22, where P is an integer greater than or equal to 3. Motor 12 is a motor or generator.

[0095] exist Figure 1 In the example, motor 12 is a three-phase motor, P equals 3, and the three phases 22 are represented as U, V, and W respectively.

[0096] The electric starter 14 includes at least P-1 switching arms 24, each switching arm 24 adapted to be connected to a corresponding phase 22 of the motor 12. Each switching arm 24 is switchable between a closed position where current flows through the arm and an open position where no current flows through the arm. Each switching arm 24 includes at least one switch 26. Preferably, each switching arm 24 includes two switches 26 connected in anti-parallel, such as... Figure 1 As shown. In this example, each switch arm 24 consists of two switches 26 connected in anti-parallel. Each switch 26 is a controllable switch, for example... Figure 1 The thyristor or transistor shown.

[0097] When the corresponding switch 26 is a thyristor, those skilled in the art will understand that the expression "open" associated with the switch arm(s) 24 including such a switch 26 should be understood as "remaining open". In practice, the thyristor can be controlled to be closed, but will automatically open and return to zero according to the forward current condition.

[0098] exist Figure 1 In the example, the electric starter 14 includes P switching arms 24, that is, the switching arm 24 of each corresponding phase 22 of the motor 12.

[0099] The AC power supply 16 itself is known, and it also has P phases.

[0100] The determining device 20 is configured to determine at least one characteristic parameter Rs, Rreq, Lf, L of the motor 12. Each characteristic parameter is preferably selected from the group consisting of: the stator resistance Rs of the motor 12; the rotor resistance Rreq of the motor 12; the leakage inductance Lf of the motor 12; and the main inductance L of the motor 12.

[0101] The determining device 20 includes a control module 30 for controlling the switching arm 24 of the electric starter 14 to generate current injection 32 on the two phases 22 of the motor 12, such as... Figure 2 As shown and further detailed below.

[0102] The determining device 20 also includes an acquisition module 34, which is used to acquire the measured values ​​of the corresponding currents I1, I2 and voltages U1, U2 of the two phases after the current injection 32 is generated.

[0103] The determining device 20 also includes a calculation module 36 for calculating at least one characteristic parameter Rs, Rreq, Lf, L of the motor 12 based on the measured values ​​of the corresponding currents I1, I2 and voltages U1, U2.

[0104] As an optional aspect, the determining device 20 is configured to determine the corresponding characteristic parameters Rs, Rreq, Lf, L of the motor 12 in at least two consecutive sequences. According to this optional aspect, the control module 30 is configured to control the switching arms 24 of the electric starter 14 to generate a current injection 32 on the two phases 22 of the motor 12, specifically controlling the closing of the corresponding switching arms(s) 24 and the opening of other switching arms 24; the acquisition module 34 is configured to acquire measurements of the corresponding current(s) and voltage(s) of the two phases 22 after the current injection 32 is generated; and the calculation module 36 is configured to calculate the characteristic parameters Rs, Rreq, Lf, L of the motor 12 based on the corresponding current(s) and voltage(s) measurements of the corresponding sequences. Furthermore, the open switching arms 24 vary from one sequence to another, preferably such that each of at least two switching arms 24 is opened once during the consecutive sequences.

[0105] According to this optional aspect, the determining device 20 further includes a diagnostic module 38 for comparing at least two values ​​determined for corresponding characteristic parameters Rs, Rreq, Lf, L in a continuous sequence, and for generating an alarm signal if the deviation between the at least two determined values ​​exceeds a predefined threshold.

[0106] exist Figure 1 In one example, the electronic determination device 20 includes, for example, a processing unit 40 formed by a memory 42 and a processor 44 coupled to the memory 42.

[0107] exist Figure 1In the example, for instance, each of the control module 30, acquisition module 34, calculation module 36, and optional diagnostic module 38 is implemented as software executable by processor 44. The memory 42 of processing unit 40 is adapted to store: control software for controlling the switching arm 24 of electric starter 14 to generate current injection 32 on two phases 22 of motor 12; acquisition software for acquiring measured values ​​of corresponding currents I1, I2 and voltages U1, U2 of the two phases after the current injection 32 is generated; calculation software for calculating at least one characteristic parameter Rs, Rreq, Lf, L of motor 12 based on the measured values ​​of corresponding currents I1, I2 and voltages U1, U2; and optional diagnostic software for comparing at least two values ​​determined for the corresponding characteristic parameters Rs, Rreq, Lf, L in a continuous sequence, and for generating an alarm signal if the deviation between these at least two determined values ​​exceeds a predefined threshold. Processor 44 of processing unit 40 is then configured to execute the control software, acquisition software, calculation software, and optional diagnostic software.

[0108] As a variant not shown, the control module 30, the acquisition module 34, the calculation module 36, and the optional diagnostic module 38 are each in the form of a programmable logic component (e.g., a field-programmable gate array or FPGA) or an application-specific integrated circuit (e.g., an application-specific integrated circuit or ASIC).

[0109] When the electronic determining device 20 is in the form of one or more software programs, i.e., in the form of a computer program, it can also be recorded on a computer-readable medium (not shown). A computer-readable medium is, for example, a medium capable of storing electronic instructions and coupled to a bus of a computer system. Examples of such media include optical discs, magneto-optical discs, ROM memory, RAM memory, any type of non-volatile memory (e.g., EPROM, EEPROM, flash memory, NVRAM), magnetic cards, or optical cards. The computer program containing the software instructions is then stored on the readable medium.

[0110] The control module 30 is configured to control the closing of corresponding(multiple) switch arms 24 and the opening of other(multiple) switch arms 24 to generate current injection 32 on two phases 22 of the motor 12.

[0111] Those skilled in the art will understand that when the control module 30 controls the (multiple) switch arms 24 to close, it means that the (multiple) switch arms 24 are switched to their closed position; and correspondingly, when the control module 30 controls the (multiple) switch arms 24 to open, it means that the (multiple) switch arms 24 are switched to their open position.

[0112] When the electric starter 14 includes P switching arms 24 (i.e., switching arms 24 of each corresponding phase 22 of the motor 12), the control module 30 is configured to control two corresponding switching arms 24 to close and other(p-2) switching arms 24 to open, so as to generate current injection 32 on the two phases 22. In other words, when the electric starter 14 includes P switching arms 24, the control module 30 is configured to control two corresponding switching arms 24 to close and (P-2) switching arms 24 to open, so as to generate the current injection 32. Figure 1 and Figure 2 In the example, where P is specifically equal to 3, the control module 30 is configured to control two corresponding switch arms 24 to close and another switch arm 24 to open in order to generate the current injection 32.

[0113] exist Figure 2 In the example, control module 30 is configured to control the closing of switch arms 24 for phases U and V, and the opening of another switch arm 24 for phase W, so as to generate current injection 32 in phases U and V. Figure 2 In this diagram, the first current curve 50 and the second current curve 52 represent the current of motor 12 in phase U (hereinafter referred to as machine current) and the corresponding machine current in phase V, respectively, while the third current curve 54 represents the machine current in phase W. The third current curve 54 is zero because, in this example, the switch arm 24 of phase W remains open. Figure 2 In the figure, the first voltage curve 60 and the second voltage curve 62 represent the voltage of the motor 12 in phase U (hereinafter referred to as the machine voltage) and the corresponding machine voltage in phase V, respectively, while the third voltage curve 64 represents the machine voltage in phase W.

[0114] Furthermore, the control module 30 is configured to, at the initial time t init After the current injection occurs at time t, the current will be generated at time t. end The corresponding previously closed switch arm 24 is opened to cut off the current injection 32.

[0115] At the initial time t init and the end time t end The duration of the current injection 32 between them is preferably a predefined time period T, such as Figure 2 As shown. The predefined time period T is preferably greater than five times the rotor time constant Tr. This ratio between the predefined time period T and the rotor time constant Tr allows for flux stability of motor 12, especially for calculating stator resistance Rs.

[0116] Alternatively, to avoid knowing the power of motor 12, the duration can be selected based on the power of electric starter 14, or the duration can be fixed and independent of the power of motor 12 or electric starter 14. In the latter case, the predefined time period T is, for example, equal to 10 seconds, which covers the entire power range of motor 12.

[0117] At the initial time t init Current injection 32 is generated and after the current injection period, i.e., at the end time t. end Previously, the acquisition module 34 was configured to acquire measurements of corresponding current(s) and voltage(s) of the two phases 22 in which current injection 32 exists. For example, the acquisition module 34 was configured to acquire measurements of a first current I1 and a first voltage U1 in the first phase 22 in which current injection 32 exists, and measurements of a second current I2 and a second voltage U2 in the second phase 22 in which current injection 32 exists.

[0118] The calculation module 36 is configured to calculate at least one characteristic parameter Rs, Rreq, Lf, L of the motor 12 based on the measured values ​​of the corresponding current(s) I1, I2 and voltage(s) U1, U2.

[0119] The calculation module 36 is configured, for example, to calculate the stator voltage Us of the motor 12 based on the voltage measurements U1 and U2 of the two phases 22, and to calculate the stator current Is of the stator based on the current measurements I1 and I2 of the two phases 22. The calculation module 36 is further configured to calculate at least one characteristic parameter Rs, Rreq, Lf, L of the motor 12 based on the values ​​of the stator voltage Us and the stator current Is.

[0120] According to this example, the calculation module 36 is typically configured to calculate the values ​​of the corresponding stator voltage Us and stator current Is based on a transformation applied to the corresponding voltage measurements U1, U2 and current measurements I1, I2 of the two phases 22. The transformation applied is, for example, the Clarke transformation.

[0121] According to this example, the calculation module 36 is preferably configured to calculate the values ​​of the corresponding stator voltage Us and stator current Is using the following equation:

[0122]

[0123] I S =I1=-I2 (2)

[0124] Where Us represents the stator voltage.

[0125] U1 and U2 represent the voltages in the first phase 22 and the second phase 22, respectively;

[0126] Is represents the stator current, and

[0127] I1 and I2 represent the currents in the first phase 22 and the second phase 22, respectively.

[0128] Calculation module 36 can alternatively be configured to calculate the values ​​of the corresponding stator voltage Us and stator current Is using the following equations:

[0129]

[0130]

[0131] Where Us, U1, U2, Is, I1 and I2 represent the same variables as in equations (1) and (2) above.

[0132] When the calculated characteristic parameter of motor 12 is stator resistance Rs, the calculation module 36 is configured, for example, to calculate the stator resistance Rs based on the integral of stator voltage Us (e.g., the integral defined by equation (1)) and the integral of stator current Is (e.g., the integral defined by equation (2)) during the duration of current injection 32.

[0133] According to this example, the calculation module 36 is preferably configured to calculate the stator resistance Rs using the following equation:

[0134]

[0135] Where Rs represents the stator resistance;

[0136] Us represents the stator voltage;

[0137] Is represents the stator current;

[0138] tinit represents the initial time of the measurement during current injection 32; alternatively, the initial time is equal to 0, i.e., the start of the sequence;

[0139] tend indicates the end time of the measurement; alternatively, the end time is at the end of the entire sequence; and

[0140] T represents the duration of the measurement.

[0141] Alternatively, the calculation module 36 is configured to calculate the ratio between the filtering of the stator voltage Us and the filtering of the stator current Is.

[0142] Since the stator voltage Us and stator current Is are usually vectors, there are different variations for calculating the stator resistance Rs of motor 12.

[0143] According to the first variation, the stator resistance Rs is calculated in each direction in a representative coordinate system that is known in itself (e.g., the dq coordinate system).

[0144] According to the second variation, the vector-based module calculates the stator resistance Rs using the following equation:

[0145]

[0146] Where Rsd represents the stator resistance Rs on the d-axis of the dq coordinate system, and

[0147] Rsq represents the stator resistance R on the q-axis of the dq coordinate system.

[0148] When the calculated characteristic parameter of motor 12 is the rotor resistance Rreq, the calculation module 36 is also configured to, after generating current injection 32, calculate the stator current I based on the stator current I at the time t0 corresponding to the maximum value of stator current Is. s The total resistance R of motor 12 is calculated using the stator voltage Us. t o t Total resistance R t o t It is equal to the sum of the stator resistance Rs and the rotor resistance Rreq.

[0149] According to this example, the calculation module 36 is preferably configured to calculate the total resistance Rtot using the following equation:

[0150]

[0151] Where Rtot represents the total resistance.

[0152] Us represents the stator voltage.

[0153] Is represents the stator current, and

[0154] t0 represents the moment corresponding to the maximum value of the stator current.

[0155] Alternatively, the calculation module 36 is configured to be a function that calculates the corresponding average values ​​of the stator voltage Us and the stator current Is when the arm is closed, i.e. when the current is not zero.

[0156] Then, the calculation module 36 is configured to calculate from the total resistance R t o t The value is obtained by subtracting the value of the stator resistance Rs from the previously calculated value of the stator resistance Rs and the total resistance R. t o t Determine the value of the rotor resistance R req The value of .

[0157] The time t0 corresponding to the maximum value of the stator current Is is usually about 5 ms after the injection begins, that is, at the initial time t. init Approximately 5ms later.

[0158] For the stator resistance Rs, according to the first variation, the total resistance R tot The calculations are performed, for example, in each direction of a representative coordinate system (e.g., the dq coordinate system); or, according to the second variation, in a vector-based module.

[0159] According to the first variant, the total resistance R t o t The values ​​are, for example, the stator resistance Rs and the rotor resistance R. req The average of the two. Furthermore, if the resistances Rs and R... req The significant differences between the two allow for the detection of problems on motor 12.

[0160] According to the second variation, the vector-based module calculates the total resistance R using the following equation. t o t :

[0161]

[0162] In addition, several alternative methods exist for obtaining the currents I1 and I2 and the voltages U1 and U2 at the time t0 corresponding to the maximum value of the stator current Is. According to the first alternative method, in each sampling period, the currents I1 and I2 and the voltages U1 and U2 are obtained only if the new value of the current is higher than the previously obtained value. If there is no update within a given time period (e.g., 10 ms), the last obtained value corresponds to the maximum value of the current and the equivalent voltage. According to the second alternative method, from the initial time t... init At the beginning of each sampling time, currents I1 and I2 and voltages U1 and U2 are acquired, and the acquisition stops when the corresponding currents I1 and I2 become zero. The maximum value of the current is then obtained by post-processing the acquired data.

[0163] When the calculated characteristic parameter of motor 12 is leakage inductance Lf, the calculation module 36 is configured to calculate the leakage inductance Lf based on the time derivative of stator current Is and stator voltage Us after the current injection 32 is generated.

[0164] According to this example, the calculation module 36 is preferably configured to calculate the leakage inductance Lf using the following equation:

[0165]

[0166] Where Lf represents leakage inductance.

[0167] Us represents the stator voltage, and

[0168] Is represents the stator current.

[0169] For the stator resistance Rs and the total resistance Rt o t The leakage inductance Lf is calculated, for example, in each direction of a representative coordinate system (e.g., the dq coordinate system); or in a vector-based module.

[0170] In addition, several alternative methods exist for calculating the time derivative of the stator current Is. According to the first alternative method, calculation module 36 is configured to calculate the leakage inductance Lf using the following equation:

[0171]

[0172] ΔT is the time between two acquisition moments;

[0173] This usually leads to the following equation:

[0174]

[0175] Where t2-t1=ΔT,

[0176] t1 and t2 are the continuously acquired time points.

[0177] t1 is chosen at the time closest to the initial time t init The moments that followed.

[0178] According to the second alternative method, from the initial time t init At the beginning of each sampling time, currents I1 and I2 and voltages U1 and U2 are acquired. Then, the stator current I is obtained by post-processing the acquired data. s The time derivative.

[0179] When the calculated characteristic parameter of motor 12 is the main inductance L, the calculation module 36 is configured to calculate based on the leakage inductance Lf, stator current Is, and stator flux Ψ during the current injection 32 duration. s points Calculate the main inductance L.

[0180] According to this example, the calculation module 36 is preferably configured to calculate the main inductance L using the following equation:

[0181]

[0182] Where L represents the main inductance.

[0183] Lf represents leakage inductance.

[0184] Is represents the stator current, and

[0185] This represents the integral of the stator flux during the current injection period of 32.

[0186] Preferred is defined by the following equation:

[0187]

[0188] Rs represents the stator resistance.

[0189] Us represents the stator voltage.

[0190] Is represents the stator current.

[0191] t init This indicates the initial moment of current injection into 32.

[0192] t end This indicates the end time of current injection 32, and

[0193] T represents the duration of current injection 32.

[0194] For stator resistance Rs, total resistance R t o t The calculation of leakage inductance Lf and main inductance L is performed, for example, in each direction of a representative coordinate system (e.g., the dq coordinate system); or based on a vector module.

[0195] In addition, there are several alternative methods to calculate the integral of equation (13), one of which is to calculate the integral from the initial time t. init At each initial sampling time, currents I1 and I2 and voltages U1 and U2 are acquired, and then the integral is obtained by post-processing the acquired data.

[0196] Therefore, the calculation module 36 is configured to calculate the aforementioned four characteristic parameters Rs, Rreq, Lf, and L of the motor 12 during current injection after the control module 30 controls the corresponding(multiple) switch arms 24 to close and the other(multiple) switch arms 24 to open.

[0197] Depending on the optional aspect, in Figure 1 In the example, the determining device 20 is preferably configured to determine the corresponding characteristic parameters Rs, Rreq, Lf, and L of the motor 12 in three consecutive sequences. Therefore, the opening of the switch arm 24 varies from one sequence to another, preferably such that each of the three switch arms 24 is opened once during the three consecutive sequences.

[0198] Therefore, in Figure 1 In the example, the diagnostic module 38 is configured to compare at least two (preferably three) values ​​determined for the corresponding feature parameters Rs, Rreq, Lf, L on a continuous sequence, and generate an alarm signal if the deviation between these determined values ​​exceeds a predefined threshold.

[0199] Now refer toFigure 3 To explain the operation of the power supply chain 10 according to the first embodiment, and in particular the operation of the determining device 20, Figure 3 A flowchart illustrating a method for determining at least one characteristic parameter Rs, Rreq, Lf, L according to the first embodiment of the method.

[0200] In the initial step 100, the electronic determining device 20, via its control module 30, controls the closing of corresponding(multiple) switch arms 24 and the opening of other(multiple) switch arms 24 to generate current injection 32 on two phases 22 of the motor 12. Specifically, when the electric starter 14 includes P switch arms 24, the control module 30 controls two corresponding switch arms 24 to close and (P-2) switch arms 24 to open to generate the current injection 32. Figure 1 and Figure 2 In the example, when P equals 3, the control module 30 therefore controls two corresponding switch arms 24 to close and another switch arm 24 to open to generate the current injection 32.

[0201] After the initial time tinit and the current injection 32 occurring during the current injection period, i.e., before the end time temp, in step 110, the electronic determination device 20 acquires, via its acquisition module 34, the measured values ​​of the corresponding current(s) and voltage(s) of the two phases 22 where the current injection 32 exists. Specifically, the acquisition module 34 acquires the measured values ​​of the first current I1 and the first voltage U1 in the first phase 22, and the measured values ​​of the second current I2 and the second voltage U2 in the second phase 22, respectively.

[0202] Furthermore, after the current injection 32 occurs at the initial time tinit, the control module 30 at the end time t end The corresponding previously closed switch arm 24 is opened to cut off the current injection 32.

[0203] Then, during the next step 120, the electronic determining device 20 calculates at least one characteristic parameter Rs, Rreq, Lf, L of the motor 12 via its calculation module 36 based on the measured values ​​of the corresponding current(s), I2 and voltage(s), U1, U2.

[0204] For example, the calculation module 36 calculates the value of the stator voltage Us based on the voltage measurements U1 and U2 of the two phases 22 and the value of the stator current Is based on the current measurements I1 and I2 of the two phases 22, respectively. Then, it calculates at least one characteristic parameter Rs, Rreq, Lf, L based on the values ​​of the stator voltage Us and the stator current Is. For example, based on equations (1) and (2), or equations (3) and (4), the values ​​of the corresponding stator voltage Us and stator current Is are typically calculated based on the corresponding transformations (e.g., Clarke transformations) applied to the corresponding voltage measurements U1 and U2 and current measurements I1 and I2 of the two phases 22.

[0205] Furthermore, when the calculated characteristic parameter of the motor 12 is the stator resistance Rs, for example, the calculation module 36 usually calculates the stator resistance Rs according to the aforementioned equation (5) or (6), based on the integral of the stator voltage Us and the integral of the stator current Is during the duration of the current injection 32.

[0206] When the calculated characteristic parameter of motor 12 is rotor resistance Rreq, the calculation module 36 usually calculates the total resistance Rtot according to the aforementioned equation (7) or (8) after the current injection 32 is generated, based on the stator voltage Us and stator current Is at the moment t0 corresponding to the maximum value of stator current Is.

[0207] When the calculated characteristic parameter of motor 12 is leakage inductance Lf, for example, the calculation module 36 usually calculates the leakage inductance Lf according to the time derivatives of stator voltage Us and stator current Is after the current injection 32 is generated, based on the aforementioned equations (9), (10) or (11).

[0208] When the calculated characteristic parameter of motor 12 is the main inductance L, for example, the calculation module 36 usually calculates the leakage inductance Lf, stator current Is, and stator flux Ψ during the duration of current injection 32 according to the aforementioned equations (12) and (13). s points Calculate the main inductance L.

[0209] exist Figure 1 In the example, during the initial control step 100, for example, the switch arms 24 of phases U and V are controlled to be closed, and the switch arm 24 of phase W is controlled to be open, so as to generate current injection 32 on phases U and V, and then the acquisition step 110 and the calculation step 120 are performed for these two phases U and V.

[0210] Then, in the next step 130, also known as the first repeating step 130, the electronic determining device 20 repeats the control step 100, the acquisition step 110 and the calculation step 120 for another open phase 22 via its control module 30, its acquisition module 34 and its calculation module 36 respectively.

[0211] For example, during the first repeating step 130, the switching arms 24 of phases U and W are controlled to be closed, and the switching arm 24 of phase V is controlled to be open, so as to generate current injection 32 in phases U and W, and the first repeating step 130 is further performed for these two phases U and W.

[0212] Then, in the next step 140, also known as the second repeating step 140, the electronic determining device 20 repeats the control step 100, the acquisition step 110 and the calculation step 120 for another opened phase 22 via its control module 30, its acquisition module 34 and its calculation module 36 respectively.

[0213] For example, during the second repeating step 140, the switching arms 24 of phases V and W are controlled to be closed, and the switching arm 24 of phase U is controlled to be open, so as to generate current injection 32 on phases V and W, and the second repeating step 140 is further performed for these two phases V and W.

[0214] Finally, in the next step 150, the electronic determining device 20 monitors the motor 12 via its diagnostic module 38 based on at least one calculated characteristic parameter Rs, Rreq, Lf, L of the motor 12. Specifically, according to an optional aspect, the diagnostic module 38 compares at least two values ​​determined for the corresponding characteristic parameters Rs, Rreq, Lf, L in a continuous sequence, and generates an alarm signal if the deviation between these at least two determined values ​​exceeds a predefined threshold.

[0215] Technicians will observe that the electronic determining device 20 executes a given sequence only once to determine at least one characteristic parameter Rs, Rreq, Lf, L; or, by changing the opening arm of the electric starter 14 from one sequence to another, executes two or three corresponding sequences in sequence, thereby allowing diagnostics of the motor 12.

[0216] In addition, the electronic determining device 20 periodically executes a given sequence or a continuous sequence, for example:

[0217] - This typically allows for the initialization of the thermal state of the motor 12 for protection each time it starts, as well as the identification of machine resistance for better torque control;

[0218] - Each time the motor 12 stops, for example, to estimate the current thermal state of the motor 12, and to allow or prevent the next machine start-up during a given period of time;

[0219] - As needed, compare the results and examine potential deviations in the evolution of resistance across different machines. Additionally, if an imbalance is detected between phases 22 of motor 12 (after the aforementioned comparisons), record it.

[0220] Determining at least one characteristic parameter Rs, Rreq, Lf, and L of motor 12 allows for several advantages. Based on the calculated stator resistance Rs, torque estimation is improved for better torque control of motor 12. Furthermore, the calculated stator resistance Rs and inductance L allow for better estimation of the mechanical speed of motor 12. Another benefit is the estimation of the machine's thermal state based on the calculated stator resistance Rs and the calculated rotor resistance Rreq. Based on this data, protection of motor 12 is improved, and electric starter 14 can authorize or deny the next start of motor 12, or initiate a delay (temporization) before the next start of motor 12.

[0221] Figure 4 and Figure 5 A second embodiment is shown, in which elements similar to those in the first embodiment described above are identified by the same reference numerals.

[0222] According to the second embodiment, the electric starter 14 includes only P-1 switching arms 24, i.e., switching arms 24 for P-1 phases 22 of the motor 12, while the remaining phases 22 of the motor 12 are directly and permanently (i.e. continuously) connected to the AC power supply 16, especially to their respective phases.

[0223] According to this second embodiment, the control module 30 is configured to control the closing of one corresponding switch arm 24 and the opening of other(multiple) switch arms 24 to generate a current injection 32 on two phases 22, namely, on the phase where the switch arm 24 is controlled to be closed and on the phase permanently connected to the AC power supply 16. In other words, according to this second embodiment, the control module 30 is configured to control the closing of a single corresponding switch arm 24 and the opening of (P-2) switch arms 24 to generate the current injection 32. Figure 4 In the example, where P is specifically equal to 3, the control module 30 is configured to control the corresponding switch arm 24 to close and the other switch arm 24 to open in order to generate the current injection 32.

[0224] Furthermore, the control module 30 is configured to, at the initial time t init After the current injection occurs at time t, the current will be generated at time t. end The corresponding previously closed switch arm 24 is opened to cut off the current injection 32.

[0225] Depending on the optional aspect, in Figure 4 In the example, the determining device 20 is configured to determine the corresponding characteristic parameters Rs, Rreq, Lf, L of the motor 12 in two consecutive sequences. Therefore, the opening of the switch arm 24 changes from one sequence to another, preferably such that each of the two switch arms 24 is opened once in the two consecutive sequences.

[0226] Therefore, in Figure 4 In the example, the diagnostic module 38 is configured to compare two values ​​determined for the corresponding feature parameters Rs, Rreq, Lf, L on two consecutive sequences, and generate an alarm signal if the deviation between the two determined values ​​exceeds a predefined threshold.

[0227] Now refer to Figure 5 To explain the operation of the power supply chain 10 according to the second embodiment, and in particular the operation of the determining device 20, Figure 5 A flowchart illustrating a method for determining at least one characteristic parameter Rs, Rreq, Lf, L of motor 12 according to a second embodiment.

[0228] According to the second embodiment, in the initial step 100, the electronic determining device 20 controls, via its control module 30, to close one corresponding switch arm 24 and open other (multiple) switch arms 24 (i.e., P-2 switch arms 24) to generate current injection 32 on the two phases 22 of the motor 12. Figure 4 In the example, when P equals 3, the control module 30 therefore controls one corresponding switch arm 24 to close and the other switch arm 24 to open to generate the current injection 32.

[0229] According to the second embodiment, the acquisition step 110, calculation step 120, first repeating step 130 and monitoring step 150 are similar to the acquisition step 110, calculation step 120, first repeating step 130 and monitoring step 150 of the first embodiment described above, and therefore will not be described again.

[0230] A technician will observe that, according to the second embodiment, the second repeating step 140 is not performed because there is a phase where the electric starter 14 is not turned on, as the motor 12 is permanently connected to the AC power supply 16 for that phase. Figure 4 In the example, the phase that is not turned on by the electric starter 14 is phase U.

[0231] In other words, in Figure 4 In the example, in the initial control step 100, for example, the switch arm 24 of phase V is controlled to be closed and the switch arm 24 of phase W is controlled to be open so as to generate current injection 32 on phases U and V, and then the acquisition step 110 and the calculation step 120 are performed on the two phases U and V.

[0232] Then, during the first repeating step 130, the switch arm 24 of phase W is controlled to be closed and the switch arm 24 of phase V is controlled to be open so as to generate current injection 32 on phases U and W, and the first repeating step 130 is further performed for these two phases U and W.

[0233] The advantages of the second embodiment are similar to those of the first embodiment described above, and therefore will not be described again.

Claims

1. An electronic determining device (20) for determining at least one characteristic parameter (Rs, Rreq, Lf, L) of a motor (12) connected to an electric starter (14), the motor (12) having P phases (22), P equal to 3, the electric starter (14) being adapted to be connected to an AC power source (16), and comprising at least P-1 switching arms (24), each switching arm (24) being connected to a corresponding phase (22) of the motor (12). The electronic determining device (20) includes: The control module (30) is configured to control the closing of the corresponding switch arm (24) and the opening of other switch arms (24) to generate current injection (32) on two phases (22) of the motor (12). The acquisition module (34) is configured to acquire the corresponding current and voltage measurements of the two phases (22) after the current injection (32) is generated; as well as The calculation module (36) is configured to calculate at least one characteristic parameter (Rs, Rreq, Lf, L) of the motor (12) based on the measured values ​​of the corresponding current and voltage. The electronic determining device (20) is configured to determine the corresponding characteristic parameters (Rs, Rreq, Lf, L) of the motor (12) in at least two consecutive sequences, and During each sequence, the control module (30) is configured to control the closing of the corresponding switch arm (24) and the opening of other switch arms (24) to generate current injection (32) on two phases of the motor (12); the acquisition module (34) is configured to acquire the measured values ​​of the corresponding current and voltage of the two phases (22) after the current injection is generated; and the calculation module (36) is configured to calculate the characteristic parameters (Rs, Rreq, Lf, L) of the motor (12) based on the measured values ​​of the corresponding current and voltage of the corresponding sequence. The open switch arm (24) changes from one sequence to another, such that each of at least two switch arms (24) is opened once during the consecutive sequence.

2. The electronic determining device (20) according to claim 1, wherein each characteristic parameter (Rs, Rreq, Lf, L) is selected from the group consisting of: The stator resistance (Rs) of the motor; The rotor resistance (Rreq) of the motor; The leakage inductance (Lf) of the motor; and The main inductance (L) of the motor.

3. The electronic determining device (20) according to claim 1 or 2, wherein, The control module (30) is configured to control the corresponding previously closed switch arm (24) to open at the end time (tend) after the current injection (32) occurs at the initial time (tinit), thereby cutting off the current injection (32).

4. The electronic determining device (20) according to claim 1 or 2, wherein the calculation module (36) is configured to calculate the value of the stator voltage (Us) of the stator of the motor (12) based on the voltage measurement values ​​of the two phases (22) and the value of the stator current (Is) of the stator based on the current measurement values ​​of the two phases (22), and the calculation module (36) is further configured to calculate at least one characteristic parameter (Rs, Rreq, Lf, L) of the motor (12) based on the values ​​of the stator voltage (Us) and the stator current (Is).

5. The electronic determining device (20) according to claim 1 or 2, wherein the calculation module (36) is configured to calculate the values ​​of the corresponding stator voltage (Us) and stator current (Is) based on the transformation of the corresponding voltage and current measurements applied to the two phases (22).

6. The electronic determining device (20) according to claim 4, wherein the calculation module (36) is configured to calculate the total resistance (Rtot) of the motor (12) based on the stator voltage (Us) and stator current (Is) at the moment (t0) corresponding to the maximum value of the stator current (Is) after the current injection (32) is generated, the total resistance (Rtot) being equal to the sum of the stator resistance (Rs) and rotor resistance (Rreq) of the motor.

7. The electronic determining device (20) according to claim 4, wherein the calculation module (36) is configured to calculate the leakage inductance (Lf) of the motor (12) based on the time derivative of the stator current (Is) and the stator voltage (Us) after the current injection (32) is generated.

8. The electronic determining device (20) according to claim 4, wherein the calculation module (36) is configured to calculate the stator resistance (Rs) of the motor (12) based on the integral of the stator voltage (Us) and the integral of the stator current (Is) during the duration of the current injection (32).

9. The electronic determining device (20) according to claim 8, wherein the calculation module (36) is configured to calculate based on the leakage inductance (Lf) of the motor (12), the stator current (Is), and the integral (φ) of the stator flux (Ψs) during the duration of current injection (32). s Calculate the main inductance (L) of the motor (12).

10. The electronic determination device (20) according to claim 1, wherein the electronic determination device (20) further comprises a diagnostic module (38) configured to compare at least two values ​​determined in a continuous sequence for corresponding feature parameters (Rs, Rreq, Lf, L), and generate an alarm signal if the deviation between the at least two determined values ​​exceeds a predefined threshold.

11. The electronic determining device (20) according to claim 3, wherein, The duration of the current injection (32) between the initial time (tinit) and the end time (tend) is a predefined time period (T).

12. The electronic determining device (20) according to claim 11, wherein, The predefined time period (T) is greater than five times the rotor time constant.

13. The electronic determining device (20) according to claim 5, wherein, The calculation module (36) is configured to calculate the values ​​of the corresponding stator voltage (Us) and stator current (Is) according to the following equation: Where Us represents the stator voltage. U1 and U2 represent the voltages in the first phase (22) and the second phase (22), respectively; Is represents the stator current, and I1 and I2 represent the currents in the first phase (22) and the second phase (22), respectively.

14. The electronic determining device (20) according to claim 6, wherein, The calculation module (36) is configured to calculate the total resistance (Rtot) according to the following equation: Where Rtot represents the total resistance. Rs represents the stator resistance of the motor. Rreq represents the rotor resistance of the motor. Us represents the stator voltage. Is represents the stator current, and t0 represents the moment corresponding to the maximum value of the stator current.

15. The electronic determining device (20) according to claim 7, wherein, The calculation module (36) is configured to calculate the leakage inductance (Lf) according to the following equation: Where Lf represents leakage inductance. Us represents the stator voltage, and Is represents the stator current.

16. The electronic determining device (20) according to claim 8, wherein, The calculation module (36) is configured to calculate the stator resistance (Rs) according to the following equation: Where Rs represents the stator resistance. Us represents the stator voltage. Is represents the stator current. tinit represents the initial moment of measurement during current injection (32), tend represents the end time of the measurement, and T represents the duration of the measurement.

17. The electronic determining device (20) according to claim 9, wherein, The calculation module (36) is configured to calculate the main inductance (L) according to the following equation: Where L represents the main inductance. Lf represents leakage inductance. Is represents the stator current, and φ s This represents the integral of the stator flux during the duration of the current injection (32).

18. The electronic determining device (20) according to claim 17, wherein, φ s Defined according to the following equation: Rs represents the stator resistance. Us represents the stator voltage. Is represents the stator current. tinit represents the initial time of current injection (32), tend represents the end time of current injection (32), and T represents the duration of current injection (32).

19. A power supply chain (10) for an electric motor (12) having P phases (22), where P equals 3, the power supply chain (10) comprising: - An electric starter (14) adapted to be connected between an AC power source (16) and a motor (12), the electric starter (14) comprising at least P-1 switching arms (24), each switching arm (24) adapted to be connected to a corresponding phase (22) of the motor (12). - Electronic determining device (20) for determining at least one characteristic parameter (Rs, Rreq, Lf, L) of motor 12. The electronic determining device (20) is the electronic determining device according to any one of claims 1-18.

20. A method for determining at least one characteristic parameter (Rs, Rreq, Lf, L) of a motor (12) connected to an electric starter (14), the motor (12) having P phases (22), where P equals 3, the electric starter (14) being adapted to be connected to an AC power source (16) and comprising at least P-1 switching arms (24), each switching arm (24) being connected to a corresponding phase (22) of the motor (12). The method is implemented by an electronic determining device (20) and includes the following steps: Control (100) to close the corresponding switch arm (24) and open the other switch arm (24) so ​​as to generate current injection (32) on the two phases (22) of the motor (12); After current injection (32) is generated, the corresponding current and voltage values ​​of the two phases (22) are obtained (110); and Calculate (120) at least one characteristic parameter (Rs, Rreq, Lf, L) of the motor (12) based on the measured values ​​of the corresponding current and voltage. Wherein, the corresponding characteristic parameters (Rs, Rreq, Lf, L) of the motor (12) are determined in at least two consecutive sequences, and During each sequence, a corresponding switch arm (24) is controlled to close and other switch arms (24) are controlled to open to generate current injection (32) on two phases of the motor (12); after the current injection, the corresponding current and voltage measurements of the two phases (22) are acquired; and the characteristic parameters (Rs, Rreq, Lf, L) of the motor (12) are calculated based on the corresponding current and voltage measurements of the corresponding sequence. The open switch arm (24) changes from one sequence to another, such that each of at least two switch arms (24) is opened once during the consecutive sequence.

21. A computer-readable medium having a computer program stored thereon, the computer program implementing the method of claim 20 when executed by a processor.

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