Motor and parameter determination method and device thereof, storage medium and program product

Abstract

The invention discloses a motor parameter determination method and device, a motor, a storage medium and a computer program product, and the method comprises the steps: transmitting a PWM signal to an inverter under the condition that the motor is static, and controlling six bridge arms of the inverter to be conducted according to a preset mode, so as to obtain a current PWM carrier period through the combination of the rated current of the motor and the three-phase current of the motor; according to the current PWM carrier wave period, the PWM signal is sent to the inverter again, the six bridge arms of the inverter are controlled again to be conducted according to the preset mode, and the line current of the motor is calculated according to the three-phase current of the motor; according to the line current of the motor, the position angle of the motor and the quadrature-axis inductance and the direct-axis inductance of the motor are calculated to serve as parameters of the motor needing to be determined. According to the scheme, the six bridge arms of the inverter are controlled to be conducted according to the preset mode, the parameters to be identified are calculated according to the obtained line current, and the identification precision and accuracy of the motor parameters can be improved.

Description

Technical Field

[0001] The present invention belongs to the field of motor technology, and specifically relates to a method, device, motor, storage medium and computer program product for determining motor parameters, and in particular to a method, device, motor, storage medium and computer program product for identifying parameters of a permanent magnet synchronous motor. Background Art

[0002] Motors (such as permanent magnet synchronous motors) have many advantages such as simple structure, small size, high efficiency, high power density, fast response speed and high safety, and are widely used in occasions requiring high performance. High-performance motor control methods - vector control, direct torque control, etc. all rely on the mathematical model of the motor without exception. However, the AC motor is a multivariable, strongly coupled, time-varying parameter nonlinear system. The motor mathematical model derived from electromagnetic field theory is a high-order, time-varying parameter mathematical model, and there is a certain coupling relationship between the various parameters. In order to obtain high-performance and accurate motor control, it is necessary to obtain accurate motor parameters. However, in related schemes, the accuracy of motor parameter acquisition cannot be guaranteed.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a method, device, motor, storage medium and computer program product for determining the parameters of a motor, so as to solve the problem that the accuracy of obtaining the motor parameters cannot be guaranteed in related schemes, so as to achieve the effect of improving the identification precision and accuracy of the motor parameters by controlling the six bridge arms of the inverter to conduct in a preset manner and then calculating the parameters to be identified based on the acquired line current.

[0005] The present invention provides a method for determining parameters of a motor, wherein the motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first switch tube and the fourth switch tube are upper bridge arm switch tubes and lower bridge arm switch tubes of an A-phase bridge arm, and are used to power a U-phase winding in the three-phase winding of the motor, the third switch tube and the sixth switch tube are upper bridge arm switch tubes and lower bridge arm switch tubes of a B-phase bridge arm, and are used to power a V-phase winding in the three-phase winding of the motor, the fifth switch tube and the second switch tube are upper bridge arm switch tubes and lower bridge arm switch tubes of a C-phase bridge arm, and are used to power a W-phase winding in the three-phase winding of the motor; the method for determining parameters of the motor comprises: obtaining a preset PWM carrier cycle as an initial PWM carrier cycle; obtaining a rated current of the motor; and, when the inverter is turned on, obtaining the three-phase winding of the motor. phase current; when the motor is stationary, according to the initial PWM carrier cycle, a PWM signal is sent to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, and obtain the current PWM carrier cycle; according to the current PWM carrier cycle, a PWM signal is sent to the inverter again to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle; calculate the required parameters of the motor according to the line current of the motor.

[0006] In some embodiments, the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, that is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm of the inverter are controlled so that the inverter is in a first working state, a second working state, a third working state, a fourth working state, and the like in sequence. The conduction modes of the first working state, the fifth working state and the sixth working state; wherein the first working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on, and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the B-phase bridge arm is turned off, and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm are both turned off; the second working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube of the B-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off The third working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned on, and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the C phase bridge arm is turned off, and the lower bridge arm switch tube is turned on; the fourth working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned off, and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube of the C phase bridge arm is turned off. The fifth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off; the sixth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on, and the lower bridge arm switch tube is turned off, the upper and lower bridge arm switch tubes of the B-phase bridge arm are both turned off, the upper bridge arm switch tube of the C-phase bridge arm is turned off, and the lower bridge arm switch tube is turned on.

[0007] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; a PWM signal is sent to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: combine the rated current of the motor, The method comprises: obtaining the three-phase current of the motor when the inverter is controlled according to the initial PWM carrier cycle, updating the initial PWM carrier cycle, and obtaining the current PWM carrier cycle, including: determining the current threshold of the motor according to the rated current of the motor; sending a PWM signal to the inverter according to the first working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the three-phase current of the motor obtained is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time, which is recorded as the PWM a first pulse width of the signal; delaying for a period of time until the acquired three-phase current of the motor is 0, sending a PWM signal to the inverter according to the second working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the acquired three-phase current of the motor is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time as the second pulse width of the PWM signal; in this way, sending the PWM signal to the inverter according to the third working state, the fourth working state, the fifth working state and the sixth working state in sequence. Send a PWM signal to turn on the inverter, and sequentially obtain a third pulse width of the PWM signal, a fourth pulse width of the PWM signal, a fifth pulse width of the PWM signal, and a sixth pulse width of the PWM signal; delay for a period of time until the acquired three-phase current of the motor is 0, and then determine the minimum pulse width among the first pulse width of the PWM signal, the second pulse width of the PWM signal, the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal to update the initial PWM carrier cycle and obtain the current PWM carrier cycle.

[0008] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; the line current of the motor includes: the first line current, the second line current, the third line current, the fourth line current, the fifth line current, and the sixth line current; sending a PWM signal to the inverter again, and controlling the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period, including: sending a PWM signal to the inverter according to the first working state. Send a PWM signal to turn on the inverter, stop sending the PWM signal to the inverter after one current PWM carrier cycle, and calculate the line current of the motor based on the three-phase current of the motor obtained at this time as the first line current; after delaying three current PWM carrier cycles, send a PWM signal to the inverter according to the second working state to turn on the inverter, stop sending the PWM signal to the inverter after one current PWM carrier cycle, and calculate the line current of the motor based on the three-phase current of the motor obtained at this time as the second line current; in this way, send a PWM signal to the inverter according to the third working state, the fourth working state, the fifth working state and the sixth working state in sequence to turn on the inverter, and obtain the third line current, the fourth line current, the fifth line current and the sixth line current in sequence to obtain the line current of the motor.

[0009] In some embodiments, the parameters of the motor include the position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor; the parameters of the motor that need to be determined are calculated based on the line current of the motor, including: the line inductance of the motor is calculated based on the line current of the motor; the shaft inductance of the motor is calculated based on the line inductance of the motor; the shaft inductance of the motor includes: the cross-axis inductance and direct-axis inductance of the motor; the position angle of the motor is calculated based on the shaft inductance of the motor; and the calculated position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor are used as the parameters of the motor that need to be determined.

[0010] In some embodiments, the line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current; the line inductance of the motor includes: a first line inductance, a second line inductance and a third line inductance; and calculating the line inductance of the motor according to the line current of the motor includes: calculating according to the line current of the motor using the following formula to obtain the line inductance of the motor:

[0011]

[0012] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, U dc is the bus voltage on the input side of the inverter, I ab is the first line current, L ba is the second line current, I bc is the third line current, I cb is the fourth line current, I ca is the fifth line current, I ac is the sixth line current, R S is the stator resistance of the motor, ΔT is the delay period, k1 is the first calculation coefficient, and k2 is the second calculation coefficient;

[0013] And / or, calculating the shaft inductance of the motor according to the line inductance of the motor, and calculating the position angle of the motor according to the shaft inductance of the motor, including: calculating the shaft inductance of the motor and the position angle of the motor according to the line inductance of the motor using the following formula:

[0014]

[0015] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, L d is the quadrature axis inductance of the motor, L q is the direct axis inductance of the motor, θ e is the position angle of the motor, and k3 is the third calculation coefficient.

[0016] Matching the above method, the present invention provides a parameter determination device for a motor on the other hand, wherein the motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, and the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, wherein the first switch tube and the fourth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm, and are used to power the U phase winding in the three-phase winding of the motor, and the third switch tube and the sixth switch tube are B The upper bridge arm switch tube and the lower bridge arm switch tube of the phase bridge arm are used to power the V-phase winding of the three-phase winding of the motor, and the fifth switch tube and the second switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm, and are used to power the W-phase winding of the three-phase winding of the motor; the parameter determination device of the motor comprises: an acquisition unit, which is configured to acquire a preset PWM carrier cycle as an initial PWM carrier cycle; acquire the rated current of the motor; and, when the inverter is turned on, acquire the three-phase current of the motor; control The control unit is configured to send a PWM signal to the inverter according to the initial PWM carrier cycle when the motor is stationary, and control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle to obtain a current PWM carrier cycle; the control unit The element is also configured to send a PWM signal to the inverter again according to the current PWM carrier cycle, and control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle; the control unit is also configured to calculate the required parameters of the motor according to the line current of the motor.

[0017] In some embodiments, the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, that is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm of the inverter are controlled so that the inverter is in a first working state, a second working state, a third working state, a fourth working state, and the like in sequence. The conduction modes of the first working state, the fifth working state and the sixth working state; wherein the first working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on, and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the B-phase bridge arm is turned off, and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm are both turned off; the second working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube of the B-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off The third working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned on, and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the C phase bridge arm is turned off, and the lower bridge arm switch tube is turned on; the fourth working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned off, and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube of the C phase bridge arm is turned off. The fifth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off; the sixth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on, and the lower bridge arm switch tube is turned off, the upper and lower bridge arm switch tubes of the B-phase bridge arm are both turned off, the upper bridge arm switch tube of the C-phase bridge arm is turned off, and the lower bridge arm switch tube is turned on.

[0018] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; the control unit sends a PWM signal to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: combine the motor The method comprises: determining a current threshold of the motor according to the rated current of the motor; sending a PWM signal to the inverter according to the first working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the three-phase current of the motor obtained is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time, which is recorded as the a first pulse width of the PWM signal; delaying for a period of time until the acquired three-phase current of the motor is 0, sending a PWM signal to the inverter according to the second working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the acquired three-phase current of the motor is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time as the second pulse width of the PWM signal; in this way, sending the PWM signal to the inverter according to the third working state, the fourth working state, the fifth working state and the sixth working state in turn. The inverter sends a PWM signal to turn on the inverter, and sequentially obtains a third pulse width of the PWM signal, a fourth pulse width of the PWM signal, a fifth pulse width of the PWM signal, and a sixth pulse width of the PWM signal; delays for a period of time until the acquired three-phase current of the motor is 0, and determines the minimum pulse width among the first pulse width of the PWM signal, the second pulse width of the PWM signal, the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal to update the initial PWM carrier cycle and obtain a current PWM carrier cycle.

[0019] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; the line current of the motor includes: the first line current, the second line current, the third line current, the fourth line current, the fifth line current, and the sixth line current; the control unit sends a PWM signal to the inverter again, and controls the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period, including: sending a PWM signal to the inverter according to the first working state; The inverter sends a PWM signal to turn on the inverter. After one current PWM carrier cycle, the PWM signal is stopped from being sent to the inverter, and the line current of the motor is calculated based on the three-phase current of the motor obtained at this time as the first line current; after a delay of three current PWM carrier cycles, a PWM signal is sent to the inverter according to the second working state to turn on the inverter. After one current PWM carrier cycle, the PWM signal is stopped from being sent to the inverter, and the line current of the motor is calculated based on the three-phase current of the motor obtained at this time as the second line current; in this way, PWM signals are sent to the inverter according to the third working state, the fourth working state, the fifth working state and the sixth working state in sequence to turn on the inverter, and the third line current, the fourth line current, the fifth line current and the sixth line current are obtained in sequence to obtain the line current of the motor.

[0020] In some embodiments, the parameters of the motor include the position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor; the control unit calculates the required parameters of the motor according to the line current of the motor, and the required parameters of the motor include: calculating the line inductance of the motor according to the line current of the motor; calculating the shaft inductance of the motor according to the line inductance of the motor; the shaft inductance of the motor includes: the cross-axis inductance and direct-axis inductance of the motor; calculating the position angle of the motor according to the shaft inductance of the motor; and using the calculated position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor as the required parameters of the motor.

[0021] In some embodiments, the line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current; the control unit, the line inductance of the motor includes: a first line inductance, a second line inductance and a third line inductance; and according to the line current of the motor, calculating the line inductance of the motor includes: according to the line current of the motor, using the following formula to calculate, to obtain the line inductance of the motor:

[0022]

[0023] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, U dc is the bus voltage on the input side of the inverter, I ab is the first line current, I ba is the second line current, I bc is the third line current, I cb is the fourth line current, I ca is the fifth line current, I ac is the sixth line current, R S is the stator resistance of the motor, ΔT is the delay period, k1 is the first calculation coefficient, and k2 is the second calculation coefficient;

[0024] And / or, the control unit calculates the shaft inductance of the motor according to the line inductance of the motor, and calculates the position angle of the motor according to the shaft inductance of the motor, including: according to the line inductance of the motor, using the following formula to calculate, to obtain the shaft inductance of the motor and the position angle of the motor:

[0025]

[0026] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, L d is the quadrature axis inductance of the motor, L q is the direct axis inductance of the motor, θ e is the position angle of the motor, and k3 is the third calculation coefficient.

[0027] Matching the above-mentioned device, the present invention further provides a motor, including: the above-mentioned device for determining the parameters of the motor.

[0028] In accordance with the above method, the present invention provides a storage medium on the other hand, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the motor parameter determination method described above.

[0029] Matching the above method, the present invention further provides a computer program product on the other hand, including a computer program, which implements the steps of the above-mentioned method for determining the parameters of the motor when executed by a processor.

[0030] Therefore, the scheme of the present invention is to make the six bridge arms of the inverter conduct in a preset manner when the motor (such as a permanent magnet synchronous motor) is stationary, adjust the pulse width according to the output current, and when the maximum value of the three-phase current is greater than the current limit value, turn off the PWM output, record the pulse width to obtain the minimum value of the six pulse widths, so as to determine the minimum pulse width T of the PWM wave; use the minimum value of the minimum pulse width T of the PWM wave as the pulse width of the next six PWM waves, control the inverter to conduct the corresponding two-phase bridge arms in the preset six conduction modes in sequence, record the line current, calculate the line inductance of the permanent magnet synchronous motor, and obtain the quadrature and direct axis inductances L of the motor. q , L d With position angle θ e , to obtain the parameters to be identified; thus, by controlling the six bridge arms of the inverter to be turned on in a preset manner, and then calculating the parameters to be identified based on the acquired line current, the identification precision and accuracy of the motor parameters can be improved.

[0031] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0032] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a flow chart of an embodiment of a method for determining parameters of a motor of the present invention;

[0034] Figure 2 A flow chart of an embodiment of the method of the present invention for updating the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle;

[0035] Figure 3 A schematic diagram of a flow chart of an embodiment of calculating the line current of the motor according to the three-phase current of the motor in the method of the present invention;

[0036] Figure 4A flow chart of an embodiment of the method of the present invention for obtaining the required parameters of the motor according to the line current of the motor;

[0037] Figure 5 It is a structural schematic diagram of an embodiment of a device for determining parameters of a motor of the present invention;

[0038] Figure 6 It is a structural schematic diagram of a permanent magnet synchronous motor drive system based on a three-phase voltage source inverter;

[0039] Figure 7 The structural diagram of the simplified equivalent circuit of the permanent magnet synchronous motor;

[0040] Figure 8 Schematic diagram of the flow chart of the permanent magnet synchronous motor parameter identification method.

[0041] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0042] 102 - acquisition unit; 104 - control unit. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] Considering that for motors (such as permanent magnet synchronous motors), if the designed motor controller parameters do not match the controlled motor parameters properly, the control performance of the entire system will be affected. Therefore, the motor parameters must be identified to obtain the actual motor parameters. Among them, the control performance of the motor is highly dependent on the accuracy of the motor parameters. Some reasons may lead to improper matching of the controller and the controlled motor parameters, such as: the motor nameplate is lost or damaged, resulting in the inability to obtain the design parameters; the motor parameters are basically dependent on the motor manufacturer, but the motor parameters provided are the design parameters of the motor design stage, and there may be errors with the parameters of the actual production motor; during the actual operation of the motor, the motor parameters will be affected by factors such as temperature, magnetic circuit saturation, and current and change.

[0045] As a branch of modern control theory, parameter identification is based on the principle of combining theoretical models with experimental data, and then analyzing and predicting to obtain accurate parameters. With the improvement of the requirements for motor control performance, the accuracy and efficiency of parameter identification are also improved. In the relevant schemes, the parameter identification methods of permanent magnet synchronous motors are mainly divided into two categories: offline identification methods and online identification methods. The basic idea of ​​offline identification is to input specific voltage and current excitation signals to the motor before the motor starts, collect the voltage, current and angle values ​​of the motor at this time through the sensor in the driver, and obtain the required motor parameters through fitting or calculation according to the mathematical model of the permanent magnet synchronous motor. The online identification method can obtain the motor parameters in real time, and adjust the control system in real time according to the real-time motor parameters to achieve better control effect.

[0046] In a motor parameter identification method provided by some schemes, the inverter is controlled in turn to conduct any two-phase bridge arms according to the first preset conduction mode and the second preset conduction mode. In the first preset conduction mode, a forward voltage pulse is applied to the winding of the permanent magnet synchronous motor, and in the second preset conduction mode, a reverse voltage pulse is applied to the winding of the permanent magnet synchronous motor; the DC bus voltage under the forward voltage pulse is obtained, and the first current value and the second current value of the corresponding winding on the conduction bridge arm are collected at different times under the forward voltage pulse; the quadrature-axis inductance parameter and the direct-axis inductance parameter are calculated according to the DC bus voltage under the forward voltage pulse, the first current value, the second current value and the current collection time interval. However, in the implementation process, a pulse signal generator is required, and it is necessary to collect many parameters such as the first bus voltage, the second bus voltage, the third bus voltage, the first line current, the second line current, the third line current, the fourth line current, the fifth line current, the sixth line current, the current collection time interval, etc., which is more complicated.

[0047] There are also some schemes that disclose methods for determining motor parameters. When the motor is stationary, a set pulse voltage is applied to the motor to determine the inductance parameters of the motor, so as to obtain the corresponding relationship between inductance and current according to the inductance parameters under different currents; wherein, in the set pulse voltage, the voltage amplitude is greater than or equal to the set amplitude, and the action duration is less than or equal to the set duration; the motor parameters include: the inductance parameters of the motor; the inductance parameters include: direct-axis inductance and cross-axis inductance; the direct-axis inductance includes: direct-axis static inductance and direct-axis dynamic inductance; the cross-axis inductance includes: cross-axis static inductance and cross-axis dynamic inductance. However, in the implementation process, it is necessary to make the rotor position 0 degrees and 90 degrees respectively, but in actual operation, especially in motors without resolver encoders, it is difficult to maintain the rotor position at a precise angle.

[0048] In other words, due to the error between the motor parameters and the actual parameters, the designed motor controller parameters do not match the controlled motor parameters properly, which in turn affects the motor controller's control performance over the motor. In addition, motor parameter identification is divided into offline parameter identification and online parameter identification. There are different identification methods for different motor parameters, and the obtained parameter accuracy is also different; even if it is the same offline parameter identification method, the implementation means are different, and not all offline parameter identification methods use the same method. For example: the motor parameters will change due to the operating temperature, among which the stator resistance and the magnetic permeability of the ferromagnetic material have a nonlinear relationship with the temperature, and the degree of magnetic circuit saturation will also affect the motor parameters.

[0049] Therefore, the scheme of the present invention proposes a method for determining the parameters of a motor, specifically a method for identifying the parameters of a permanent magnet synchronous motor. When the motor is stationary, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to six preset conduction modes, and the pulse width is adjusted according to the output current, and then the parameters to be identified are calculated. This can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0050] According to an embodiment of the present invention, a method for determining parameters of a motor is provided. Figure 1 A schematic flow chart of an embodiment of the method of the present invention is shown. The motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, and the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first switch tube and the fourth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, and are used to power the U-phase winding in the three-phase winding of the motor, the third switch tube and the sixth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and are used to power the V-phase winding in the three-phase winding of the motor, the fifth switch tube and the second switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm, and are used to power the W-phase winding in the three-phase winding of the motor, the first switch tube is such as the switch tube VT1, the second switch tube is such as the switch tube VT2, the third switch tube is such as the switch tube VT3, the fourth switch tube is such as the switch tube VT4, the fifth switch tube is such as the switch tube VT5, and the sixth switch tube is such as the switch tube VT6. Figure 6 Figure 1 is a schematic diagram of the structure of a permanent magnet synchronous motor drive system based on a three-phase voltage source inverter. Figure 6 The permanent magnet synchronous motor drive system based on a three-phase voltage source inverter shown in FIG. 1 includes a rectifier, a bus capacitor and an inverter. The rectifier is composed of six diodes forming a diode rectifier full bridge. The voltage across the bus capacitor is the bus voltage U DCThe inverter consists of six switch tubes VT1, VT2, VT3, VT4, VT5 to VT6 with freewheeling diodes to form a switch tube inverter full bridge. VT1 and VT4 are the upper and lower tubes of the A-phase bridge arm, VT3 and VT6 are the upper and lower tubes of the B-phase bridge arm, and VT5 and VT2 are the upper and lower tubes of the C-phase bridge arm. The permanent magnet synchronous motor drive system based on the three-phase voltage source inverter provides three-phase current i for the three-phase windings u, v, and w of the motor after rectification and inversion based on the three-phase alternating current AC. A 、i B and i C .

[0051] In some embodiments, the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, that is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm of the inverter are controlled so that the inverter is in the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state conduction mode in sequence.

[0052] Among them, the first working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the B-phase bridge arm is turned off and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm are both turned off.

[0053] The second working state is: the upper bridge arm switch tube of the A phase bridge arm of the inverter is turned off and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube of the B phase bridge arm is turned on and the lower bridge arm switch tube is turned off, and the upper and lower bridge arm switch tubes of the C phase bridge arm are both turned off.

[0054] The third working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned on and the lower bridge arm switch tube is turned off, and the upper bridge arm switch tube of the C phase bridge arm is turned off and the lower bridge arm switch tube is turned on.

[0055] The fourth working state is: the upper arm switch tube and the lower arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper arm switch tube of the B phase bridge arm is turned off, and the lower arm switch tube is turned on, and the upper arm switch tube of the C phase bridge arm is turned on, and the lower arm switch tube is turned off.

[0056] The fifth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off.

[0057] The sixth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper and lower bridge arm switch tubes of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned off and the lower bridge arm switch tube is turned on.

[0058] Figure 6 The middle inverter adopts upper and lower tube commutation. In the scheme of the present invention, seven working states are defined, namely the first working state, the second working state, the third working state, the fourth working state, the fifth working state, the sixth working state and the seventh working state.

[0059] Among them, the first working state: the upper tube of phase A is turned on and the lower tube is turned off, the upper tube of phase B is turned off and the lower tube is turned on, and both the upper and lower tubes of phase C are turned off; that is, VT1 and VT6 are turned on, and the rest are turned off.

[0060] The second working state: the upper tube of phase A is turned off and the lower tube is turned on, the upper tube of phase B is turned on and the lower tube is turned off, and both the upper and lower tubes of phase C are turned off; that is, VT4 and VT3 are turned on, and the rest are turned off.

[0061] The third working state: the upper and lower tubes of phase A are both turned off, the upper tube of phase B is turned on and the lower tube is turned off, the upper tube of phase C is turned off and the lower tube is turned on; that is, VT3 and VT2 are turned on, and the rest are turned off.

[0062] The fourth working state: the upper and lower tubes of phase A are both turned off, the upper tube of phase B is turned off and the lower tube is turned on, the upper tube of phase C is turned on and the lower tube is turned off; that is, VT6 and VT5 are turned on, and the rest are turned off.

[0063] The fifth working state: the upper tube of phase A is turned off and the lower tube is turned on, the upper and lower tubes of phase B are turned off, the upper tube of phase C is turned on and the lower tube is turned off; that is, VT4 and VT5 are turned on, and the rest are turned off.

[0064] The sixth working state: the upper tube of phase A is turned on and the lower tube is turned off, the upper and lower tubes of phase B are turned off, the upper tube of phase C is turned off and the lower tube is turned on; that is, VT1 and VT2 are turned on, and the rest are turned off.

[0065] The seventh working state: the three-phase power devices A, B, and C are all turned off.

[0066] In the scheme of the present invention, when the motor is stationary, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the preset six conduction modes, and then the pulse width is adjusted according to the output current, and the line current of the motor is obtained, and then the line inductance of the permanent magnet synchronous motor is calculated to obtain the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0067] In the scheme of the present invention, Figure 1As shown, the method for determining the parameters of the motor includes: steps S110 to S140.

[0068] In step S110, a preset PWM carrier cycle is obtained as an initial PWM carrier cycle; the rated current of the motor is obtained, such as obtaining the rated current I of the permanent magnet synchronous motor. e_motor ; and, when the inverter is turned on, obtaining the three-phase current of the motor (such as current Ia, Ib, Ic).

[0069] At step S120, when the motor is stationary, according to the initial PWM carrier cycle, the motor controller is controlled to send a drive signal to the drive system of the motor, that is, to send a PWM signal to the inverter, and the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are controlled to be turned on in a preset manner, so as to: update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, and obtain the current PWM carrier cycle. Specifically, in the process of controlling the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, the three-phase current of the motor is obtained, and the pulse width of the PWM signal is recorded; and then according to the three-phase current of the motor and the pulse width of the PWM signal, the initial PWM carrier cycle is updated to obtain the current PWM carrier cycle.

[0070] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state. In step S120, a PWM signal is sent to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: update the initial PWM carrier period in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period, and obtain the specific process of the current PWM carrier period, see the following exemplary description.

[0071] Combine the following Figure 2The method of the present invention is shown as a flow chart of an embodiment of updating the initial PWM carrier period in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period, further illustrating the specific process of updating the initial PWM carrier period in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period in step S120, including: steps S210 to S250.

[0072] Step S210: Determine the current threshold of the motor according to the rated current of the motor. e_motor The setting coefficient is times, which is determined as the current threshold value I of the motor threshold , set the coefficient to 0.8.

[0073] Step S220: sending a PWM signal to the inverter in the first working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the three-phase current of the motor is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time, which is recorded as the first pulse width of the PWM signal.

[0074] Step S230, delay for a period of time until the acquired three-phase current of the motor is 0, send a PWM signal to the inverter according to the second working state to turn on the inverter, and then adjust the pulse width of the PWM signal until the maximum value of the acquired three-phase current of the motor is greater than the current threshold of the motor, stop sending the PWM signal to the inverter, and record the pulse width of the PWM signal at this time, which is recorded as the second pulse width of the PWM signal.

[0075] Step S240, in this way, PWM signals are sent to the inverter in the third working state, the fourth working state, the fifth working state and the sixth working state to turn on the inverter, and the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal and the sixth pulse width of the PWM signal are obtained in sequence. The first pulse width of the PWM signal is such as pulse width T1, the second pulse width of the PWM signal is such as pulse width T2, the third pulse width of the PWM signal is such as pulse width T3, the fourth pulse width of the PWM signal is such as pulse width T4, the fifth pulse width of the PWM signal is such as pulse width T5, and the sixth pulse width of the PWM signal is such as pulse width T6.

[0076] Step S250, delay for a period of time until the acquired three-phase current of the motor is 0, determine the minimum pulse width among the first pulse width of the PWM signal, the second pulse width of the PWM signal, the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal, so as to update the initial PWM carrier period and obtain the current PWM carrier period.

[0077] Figure 7 This is a simplified structural diagram of the equivalent circuit of a permanent magnet synchronous motor. Figure 7 As shown in FIG. 1 , the simplified equivalent circuit of the permanent magnet synchronous motor includes: a power supply, a switch S, a diode D, a resistor R and an inductor Lbc. The power supply voltage is v_dc. The positive electrode of the power supply is connected to the negative electrode of the power supply through the switch S, the resistor R and the inductor Lbc; the negative electrode of the power supply is grounded GND. The anode of the diode D is connected to the common terminal between the switch S and the resistor R; the cathode of the diode D is grounded GND. The resistance value of the resistor R is R=2Rs, where Rs is the resistance value of the motor stator resistance.

[0078] like Figure 6 As shown, disconnect the motor phase A, connect the B and C phases to the positive and negative terminals of the DC power supply respectively, and fix the motor rotor. At this time, the system is simplified to an RL circuit, that is, Figure 7 As shown. The power supply voltage v_dc is the bus voltage of the motor controller, the resistance R is twice the stator resistance Rs of the motor, and the inductance Lbc is the stator line inductance. When the switch S is closed, the voltage u and current i in the RL circuit satisfy:

[0079]

[0080] Among them, L line is the inductance value of the stator line inductance.

[0081] Because the stator resistance of a high-power motor is small, when the current is not large, R*i can be ignored, and the above formula can be simplified to:

[0082]

[0083] From this we can get:

[0084] L line =∫udt / i (3)

[0085] That is, the inductance L line It is equal to the integral of the voltage u divided by the inductance L line The current i in, when the input voltage U is constant, the above formula can be transformed into:

[0086] L line =U*t / i (4).

[0087] At this time, the inductance L line The current i and voltage U in the equation are in a linear relationship. This linear relationship only holds true when the current i is very small, i.e., in the initial stage of the RL inertial response.

[0088] Where R is the resistance value in the simplified equivalent circuit of the motor, which is twice the stator resistance Rs of the motor; u is the total load voltage in the equivalent circuit; i is the current flowing in the equivalent circuit; L line is the line inductance, that is Figure 7 L shown in bc ; t is the time of the initial stage of RL inertial response.

[0089] Figure 8 Figure 1 is a flow chart of the permanent magnet synchronous motor parameter identification method. Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method includes:

[0090] Step 1: Initialize all parameter variables (such as working status, PWM pulse width, extension time, etc.), set the PWM carrier cycle, and set the rated current I of the permanent magnet synchronous motor. e_motor Calculate the current threshold I threshold , and then execute step 2. Specifically, the carrier frequency can be selected according to the voltage level of the inverter. For example, when the voltage level of the inverter is DC 540V, the carrier frequency is selected as 4kHz. The PWM carrier period can be determined according to the carrier frequency. e_motor Calculate the current threshold I threshold The way is as follows:

[0091] I threshold =0.8*I e_motor (5).

[0092] Step 2: Enable PWM output, perform three-phase current sampling, and conduct the inverter according to the first working state (A+B-) to detect and adjust the pulse width. For example, a value can be obtained for the pulse width detection, and the value can be added or subtracted according to the three-phase current. Different pulse widths correspond to different three-phase current values. When the maximum value of the three-phase current is greater than the set current threshold I threshold When the PWM output is turned off, the pulse width T1 at this time is recorded, and then step 3 is executed. Among them, the first working state (A+B-) is that the upper tube of phase A is turned on and the lower tube is turned off, the upper tube of phase B is turned off and the lower tube is turned on, and both the upper and lower tubes of phase C are turned off.

[0093] Step 3, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the second working state (A-B+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T2 at this time, and then execute step 4. Among them, there are two working states (A-B+), that is, the upper tube of phase A is turned off and the lower tube is turned on, the upper tube of phase B is turned on and the lower tube is turned off, and the upper and lower tubes of phase C are turned off.

[0094] Step 4: Sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the third working state (B+C-), and perform pulse width detection and adjustment. When the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T3 at this time, and then execute step 5. Among them, the third working state (B+C-), that is, the upper and lower tubes of phase A are turned off, the upper tube of phase B is turned on and the lower tube is turned off, and the upper tube of phase C is turned off and the lower tube is turned on.

[0095] Step 5, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the fourth working state (B-C+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T4 at this time, and then execute step 6. Among them, the fourth working state (B-C+) is that both the upper and lower tubes of phase A are turned off, the upper tube of phase B is turned off and the lower tube is turned on, and the upper tube of phase C is turned on and the lower tube is turned off.

[0096] Step 6, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the fifth working state (C+A-), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T5 at this time, and then execute step 7. Among them, the fifth working state (C+A-), that is, the upper tube of phase A is turned off and the lower tube is turned on, the upper and lower tubes of phase B are turned off, and the upper tube of phase C is turned on and the lower tube is turned off.

[0097] Step 7, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the sixth working state (C-A+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T6 at this time, and then execute step 8. Among them, the sixth working state (C-A+) is that the upper tube of phase A is turned on and the lower tube is turned off, the upper and lower tubes of phase B are turned off, and the upper tube of phase C is turned off and the lower tube is turned on.

[0098] Step 8: Delay for a while until the current returns to 0, select the minimum pulse width among the six pulse widths as the pulse width T of the PWM wave, that is, T=min(T1, T2, T3, T4, T5, T6); set T as the period of the PWM carrier, and then execute step 9.

[0099] By Figure 7 From the description, it can be seen that in the simplified equivalent circuit of the motor, when the current is not large, especially when the input voltage is constant, the inductor current and voltage show a linear relationship. When the voltage pulse width is small, the current basically changes linearly. When the current is disconnected, the current slowly decreases; Steps 2 to 7 are respectively in accordance with the preset conduction state, so that the six bridge arms of the inverter are turned on in the preset manner, achieving the same Figure 7 The simplified RL circuit of the system described in the figure is used to determine the minimum pulse width T of the PWM wave. Since the existence of stray inductance, parasitic inductance, stray capacitance, parasitic capacitance, etc. in the whole system will cause the time when the maximum current in the three-phase current reaches the set threshold current to be inconsistent, that is, the PWM wave pulse width time is inconsistent, so steps 2 to 7 are to eliminate the influence of stray inductance, parasitic inductance, stray capacitance, parasitic capacitance, etc. on the line inductance in the system, and the minimum pulse width T is the required pulse width. The delay of each step is to make the current in the circuit return to 0, that is, there is only a single current generated by the wave in the circuit each time.

[0100] In the scheme of the present invention, when the motor is stationary, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the six preset conduction modes, and the pulse width is adjusted according to the output current. When the maximum value of the three-phase current is greater than the current limit value, the PWM output is turned off, and the pulse width is recorded to obtain the minimum value of the six pulse widths; this minimum pulse width is used as the pulse width of the next six PWM waves, and then the line current of the motor is obtained, and the line inductance of the permanent magnet synchronous motor is calculated to calculate the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0101] At step S130, according to the current PWM carrier cycle, the motor controller is controlled again to send a drive signal to the drive system of the motor, that is, to send a PWM signal to the inverter again, and the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are controlled again to be turned on in a preset manner, so as to calculate the line current of the motor based on the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle.

[0102] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state. The line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current, and a sixth line current, wherein the first line current is such as the line current I ab , the second line current is the line current I ba 、The third line current is the line current I bc 、The fourth line current is the line current I cb 、The fifth line current is the line current I ca 、The sixth line current is the line current I ac In step S130, a PWM signal is sent to the inverter again, and the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are controlled again to be turned on in a preset manner, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, as shown in the following exemplary description.

[0103] Combine the following Figure 3 The method of the present invention is a flowchart of an embodiment of calculating the line current of the motor according to the three-phase current of the motor, further illustrating the specific process of calculating the line current of the motor according to the three-phase current of the motor in step S130, including: steps S310 to S330.

[0104] Step S310: Send a PWM signal to the inverter in the first working state to turn on the inverter. After one current PWM carrier cycle, stop sending the PWM signal to the inverter, and calculate the line current of the motor based on the three-phase current of the motor obtained at this time as the first line current.

[0105] Step S320, after a delay of three current PWM carrier cycles, sending a PWM signal to the inverter in the second working state to turn on the inverter, and after one current PWM carrier cycle, stopping sending the PWM signal to the inverter, and calculating the line current of the motor based on the three-phase current of the motor obtained at this time as the second line current.

[0106] Step S330, thereby, sending PWM signals to the inverter in the third working state, the fourth working state, the fifth working state and the sixth working state in sequence to turn on the inverter, and obtaining the third line current, the fourth line current, the fifth line current and the sixth line current in sequence to obtain the line current of the motor.

[0107] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes:

[0108] Step 9: Sample the three-phase current, and turn on the inverter according to the first working state (A+B-). After a time T, turn off the PWM output and calculate the line current I ab , then proceed to step 10.

[0109] Step 10: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the second working state (A-B+). After one T time, turn off the PWM output and calculate the line current I ba , then proceed to step 11.

[0110] Step 11: Sample the three-phase current, delay for 3 T times (wait for the current to return to 0), and turn on the inverter according to the third working state (B+C-). After a T time, turn off the PWM output and calculate the line current I bc , then proceed to step 12.

[0111] Step 12: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the fourth working state (B-C+). After one T time, turn off the PWM output and calculate the line current I cb , then proceed to step 13.

[0112] Step 13: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the fifth working state (C+A-). After one T time, turn off the PWM output and calculate the line current I ca , then proceed to step 14.

[0113] Step 14: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the sixth working state (C-A+). After one T time, turn off the PWM output and calculate the line current I ac , then proceed to step 15.

[0114] Steps 9 to 14 are to further obtain the line current I in six simplified equivalent circuits after the minimum pulse width of the PWM wave is determined.ab ,I ba ,I bc ,I cb ,I ca ,I ac , and then calculate the motor parameters cross-axis and direct-axis inductance L through the formula q , L d With position angle θ e .

[0115] In the scheme of the present invention, after determining the pulse width of the next six PWM waves, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the preset six conduction modes, the line current is recorded, and the line inductance of the permanent magnet synchronous motor is calculated to obtain the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0116] In step S140, the required parameters of the motor are calculated based on the line current of the motor.

[0117] The scheme of the present invention proposes a parameter identification scheme for a permanent magnet synchronous motor. When the motor is stationary, the inverter is controlled in sequence to turn on the corresponding two-phase bridge arms according to six preset conduction modes, and the pulse width is adjusted according to the output current. When the maximum value of the three-phase current is greater than the current limit value, the pulse width modulation (PWM) output is turned off, and the pulse width is recorded to obtain the minimum value of the six pulse widths; this minimum pulse width is used as the pulse width of the next six PWM waves, and the inverter is controlled in sequence to turn on the corresponding two-phase bridge arms according to the six preset conduction modes, and the line current is recorded. The line inductance of the permanent magnet synchronous motor is calculated to calculate the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0118] In some embodiments, the parameters of the motor include the position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor; the specific process of calculating the required parameters of the motor according to the line current of the motor in step S140, that is, calculating the position angle of the motor, and the cross-axis inductance and direct-axis inductance of the motor according to the line current of the motor, as the specific process of determining the parameters of the motor, is described in the following exemplary embodiment.

[0119] Combine the following Figure 4 The method of the present invention is shown as a flowchart of an embodiment of obtaining the required parameters of the motor according to the line current of the motor, further illustrating the specific process of obtaining the required parameters of the motor according to the line current of the motor in step S140, including: steps S410 to S430.

[0120] Step S410: Calculate the line inductance of the motor according to the line current of the motor.

[0121] In some embodiments, the line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current, wherein the first line current is the line current I ab , the second line current is the line current I ba 、The third line current is the line current I bc 、The fourth line current is the line current I cb 、The fifth line current is the line current I ca 、The sixth line current is the line current I ac The line inductance of the motor in step S410 includes: a first line inductance, a second line inductance and a third line inductance; the line inductance of the motor is calculated according to the line current of the motor, including: according to the line current of the motor, the line inductance of the motor is calculated using the following formula:

[0122]

[0123] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, U dc is the bus voltage on the input side of the inverter, I ab is the first line current, I ba is the second line current, I bc is the third line current, I cb is the fourth line current, I ca is the fifth line current, I ac is the sixth line current, R S is the stator resistance of the motor, ΔT is the delay period, k1 is the first calculation coefficient (preferably k1 is 2), k2 is the second calculation coefficient (preferably k2 is 0.5);

[0124] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes: step 15, calculating the line inductance L in the natural coordinate system ab ,I bc , L ca , then proceed to step 16.

[0125] Depend on Figure 7 The simplified equivalent circuit of the permanent magnet synchronous motor shown in the figure shows that the line inductance L line :

[0126]

[0127] Among them, U line is the inductance L bc The voltage, I line is the inductance L bc Δt is the delay period, i.e. the pulse width T of the minimum pulse width PWM wave in step 8.

[0128] Therefore, the inductance L in the natural coordinate system is ab , L bc , L ca The expression is:

[0129]

[0130] Wherein, line current:

[0131]

[0132] In the scheme of the present invention, after obtaining the line current of the motor, the line inductance of the motor is calculated according to the line current of the motor to serve as a basis for calculating the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor. This can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0133] Step S420, calculating the shaft inductance of the motor according to the line inductance of the motor; the shaft inductance of the motor includes: the quadrature-axis inductance and the direct-axis inductance of the motor.

[0134] Step S430, calculating the position angle of the motor according to the shaft inductance of the motor; and using the calculated position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor as the parameters of the motor to be determined.

[0135] In the scheme of the present invention, after obtaining the line current of the motor, the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor are calculated according to the line current of the motor as the parameters of the motor to be determined. This can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0136] In some implementations, in step S420 and step S430, the shaft inductance of the motor is calculated according to the line inductance of the motor, and the position angle of the motor is calculated according to the shaft inductance of the motor, including: according to the line inductance of the motor, the shaft inductance of the motor and the position angle of the motor are calculated using the following formula:

[0137]

[0138] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, L d is the quadrature axis inductance of the motor, L q is the direct axis inductance of the motor, θ e is the position angle of the motor, k3 is the third calculation coefficient (preferably k3 is 2).

[0139] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes: step 16, calculating the shaft inductance L d , L q , then proceed to step 17.

[0140] Line inductance L in natural coordinate system ab , L bc , L ca And shaft inductance L d , L q The relationship between them is as follows:

[0141]

[0142] Let A = L d +L q , B=L d -L q , L0=L ab -A, Then we have:

[0143]

[0144] Detailed calculation:

[0145]

[0146] Step 17: Calculate the position angle θ e .

[0147] make Then we have:

[0148]

[0149] Detailed calculation:

[0150]

[0151] Among these parameters, θ e That is, the motor position angle to be identified, L q , Ld That is, the AC and DC axis inductance of the motor to be obtained. Formulas (1)-(4) are the principles for calculating line inductance, where formula (1) is obtained by Figure 7 The circuit is easy to obtain; formula (5) is the current threshold calculation formula; formulas (6)-(8) are the motor line inductance calculation formulas in the present invention; formula (9) is a known formula in the industry; formulas (10)-(20) are the quadrature and direct axis inductance and position angle calculation formulas in the present invention.

[0152] Among them, I e_motor is the rated current of the motor, I threshold is the current threshold that the motor current is set to reach; T1~T6 are the time required for the maximum current in the three-phase current to be greater than the set current threshold under the six working conditions, that is, the PWM wave pulse width under the six working conditions; T is the minimum pulse width among the six pulse widths of T1~T6; I ab ,I ba ,I bc ,I cb ,I ca ,I ac are the line currents sampled in steps 9 to 14 respectively; L ab , L bc , L ca are the line inductance of the motor; U dc is the bus voltage of the motor controller; L d , L q They are the direct-axis and quadrature-axis inductances of the motor, Theta_t (i.e. θ t ) or θ e is the motor position angle; A, B, L0, L1, M0, M1, M2 are the parameters to be identified for the convenience of calculation: the AC and DC axis inductances Lq, Ld and the position angle θ e The defined intermediate variables have no special meaning.

[0153] In the scheme of the present invention, the shaft inductance of the motor is calculated based on the line inductance of the motor, and the position angle of the motor is calculated based on the shaft inductance of the motor, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters and ensure the accuracy of the motor parameter acquisition.

[0154] The scheme of the present invention proposes a permanent magnet synchronous motor parameter identification scheme, which is not only applicable to the field of electric vehicles, but also to CNC machine tools, machinery manufacturing, industrial robots, aerospace and other permanent magnet synchronous motor application occasions. The scheme of the present invention can improve the identification accuracy of permanent magnet synchronous motor parameters and the accuracy of identification parameters, which is conducive to the rapid matching of the motor controller and the permanent magnet synchronous motor, and is conducive to the precise control of the motor, ensuring the efficient operation of the motor, and improving the robustness of the control system. The method simplifies the calculation process, is easy to implement, reliable in control, easy to implement, and convenient for promotion and use.

[0155] The technical solution of this embodiment is adopted. When the motor (such as a permanent magnet synchronous motor) is stationary, the six bridge arms of the inverter are turned on in a preset manner, the pulse width is adjusted according to the output current, and when the maximum value of the three-phase current is greater than the current limit value, the PWM output is turned off, and the pulse width is recorded to obtain the minimum value of the six pulse widths to determine the minimum pulse width T of the PWM wave; the minimum value of the minimum pulse width T of the PWM wave is used as the pulse width of the next six PWM waves, and the inverter is controlled in turn to turn on the corresponding two-phase bridge arms in the preset six conduction modes, the line current is recorded, and the line inductance of the permanent magnet synchronous motor is calculated to obtain the quadrature and direct axis inductances L of the motor. q , L d With position angle θ e , to obtain the parameters to be identified; thus, by controlling the six bridge arms of the inverter to be turned on in a preset manner, and then calculating the parameters to be identified based on the acquired line current, the identification precision and accuracy of the motor parameters can be improved.

[0156] According to an embodiment of the present invention, a motor parameter determination device corresponding to the motor parameter determination method is also provided. Figure 5 A schematic structural diagram of an embodiment of the device of the present invention is shown. The motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, and the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first switch tube and the fourth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, and are used to power the U-phase winding in the three-phase winding of the motor, the third switch tube and the sixth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and are used to power the V-phase winding in the three-phase winding of the motor, the fifth switch tube and the second switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm, and are used to power the W-phase winding in the three-phase winding of the motor, the first switch tube is such as the switch tube VT1, the second switch tube is such as the switch tube VT2, the third switch tube is such as the switch tube VT3, the fourth switch tube is such as the switch tube VT4, the fifth switch tube is such as the switch tube VT5, and the sixth switch tube is such as the switch tube VT6; Figure 6Figure 1 is a schematic diagram of the structure of a permanent magnet synchronous motor drive system based on a three-phase voltage source inverter. Figure 6 The permanent magnet synchronous motor drive system based on a three-phase voltage source inverter shown in FIG. 1 includes a rectifier, a bus capacitor and an inverter. The rectifier is composed of six diodes forming a diode rectifier full bridge. The voltage across the bus capacitor is the bus voltage U DC The inverter consists of six switch tubes VT1, VT2, VT3, VT4, VT5 to VT6 with freewheeling diodes to form a switch tube inverter full bridge. VT1 and VT4 are the upper and lower tubes of the A-phase bridge arm, VT3 and VT6 are the upper and lower tubes of the B-phase bridge arm, and VT5 and VT2 are the upper and lower tubes of the C-phase bridge arm. The permanent magnet synchronous motor drive system based on the three-phase voltage source inverter provides three-phase current i for the three-phase windings u, v, and w of the motor after rectification and inversion based on the three-phase alternating current AC. A 、i B and i C .

[0157] In some embodiments, the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, that is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm of the inverter are controlled so that the inverter is in the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state conduction mode in sequence.

[0158] Among them, the first working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the B-phase bridge arm is turned off and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm are both turned off.

[0159] The second working state is: the upper bridge arm switch tube of the A phase bridge arm of the inverter is turned off and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube of the B phase bridge arm is turned on and the lower bridge arm switch tube is turned off, and the upper and lower bridge arm switch tubes of the C phase bridge arm are both turned off.

[0160] The third working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned on and the lower bridge arm switch tube is turned off, and the upper bridge arm switch tube of the C phase bridge arm is turned off and the lower bridge arm switch tube is turned on.

[0161] The fourth working state is: the upper arm switch tube and the lower arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper arm switch tube of the B phase bridge arm is turned off, and the lower arm switch tube is turned on, and the upper arm switch tube of the C phase bridge arm is turned on, and the lower arm switch tube is turned off.

[0162] The fifth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off.

[0163] The sixth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper and lower bridge arm switch tubes of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned off and the lower bridge arm switch tube is turned on.

[0164] Figure 6 The middle inverter adopts upper and lower tube commutation. In the scheme of the present invention, seven working states are defined, namely the first working state, the second working state, the third working state, the fourth working state, the fifth working state, the sixth working state and the seventh working state.

[0165] Among them, the first working state: the upper tube of phase A is turned on and the lower tube is turned off, the upper tube of phase B is turned off and the lower tube is turned on, and both the upper and lower tubes of phase C are turned off; that is, VT1 and VT6 are turned on, and the rest are turned off.

[0166] The second working state: the upper tube of phase A is turned off and the lower tube is turned on, the upper tube of phase B is turned on and the lower tube is turned off, and both the upper and lower tubes of phase C are turned off; that is, VT4 and VT3 are turned on, and the rest are turned off.

[0167] The third working state: the upper and lower tubes of phase A are both turned off, the upper tube of phase B is turned on and the lower tube is turned off, the upper tube of phase C is turned off and the lower tube is turned on; that is, VT3 and VT2 are turned on, and the rest are turned off.

[0168] The fourth working state: the upper and lower tubes of phase A are both turned off, the upper tube of phase B is turned off and the lower tube is turned on, the upper tube of phase C is turned on and the lower tube is turned off; that is, VT6 and VT5 are turned on, and the rest are turned off.

[0169] The fifth working state: the upper tube of phase A is turned off and the lower tube is turned on, the upper and lower tubes of phase B are turned off, the upper tube of phase C is turned on and the lower tube is turned off; that is, VT4 and VT5 are turned on, and the rest are turned off.

[0170] The sixth working state: the upper tube of phase A is turned on and the lower tube is turned off, the upper and lower tubes of phase B are turned off, the upper tube of phase C is turned off and the lower tube is turned on; that is, VT1 and VT2 are turned on, and the rest are turned off.

[0171] The seventh working state: the three-phase power devices A, B, and C are all turned off.

[0172] In the scheme of the present invention, when the motor is stationary, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the preset six conduction modes, and then the pulse width is adjusted according to the output current, and the line current of the motor is obtained, and then the line inductance of the permanent magnet synchronous motor is calculated to obtain the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0173] In the scheme of the present invention, Figure 5 As shown, the device for determining the parameters of the motor includes: an acquisition unit 102 and a control unit 104 .

[0174] The acquisition unit 102 is configured to acquire a preset PWM carrier cycle as an initial PWM carrier cycle; acquire the rated current of the motor, such as acquiring the rated current I of the permanent magnet synchronous motor. e_motor and, when the inverter is turned on, obtaining the three-phase current of the motor (such as current Ia, Ib, Ic). The specific function and processing of the obtaining unit 102 refer to step S110.

[0175] The control unit 104 is configured to control the motor controller to send a drive signal to the drive system of the motor, i.e., send a PWM signal to the inverter, and control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner according to the initial PWM carrier cycle when the motor is stationary, so as to update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, and obtain the current PWM carrier cycle. Specifically, in the process of controlling the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, the three-phase current of the motor is obtained, and the pulse width of the PWM signal is recorded; and then according to the three-phase current of the motor and the pulse width of the PWM signal, the initial PWM carrier cycle is updated to obtain the current PWM carrier cycle. The specific functions and processing of the control unit 104 refer to step S120.

[0176] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state. The control unit 104 sends a PWM signal to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: update the initial PWM carrier period in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier period, and obtain the current PWM carrier period, including:

[0177] The control unit 104 is further configured to determine the current threshold of the motor according to the rated current of the motor. e_motor The setting coefficient is times, which is determined as the current threshold value I of the motor threshold , set the coefficient to 0.8. The specific functions and processing of the control unit 104 are also shown in step S210.

[0178] The control unit 104 is further configured to send a PWM signal to the inverter in the first working state to turn on the inverter, and then adjust the pulse width of the PWM signal until the maximum value of the three-phase current of the motor obtained is greater than the current threshold of the motor, stop sending the PWM signal to the inverter, and record the pulse width of the PWM signal at this time as the first pulse width of the PWM signal. The specific functions and processing of the control unit 104 are also shown in step S220.

[0179] The control unit 104 is further configured to delay for a period of time until the three-phase current of the motor is 0, and then send a PWM signal to the inverter to turn on the inverter according to the second working state, and then adjust the pulse width of the PWM signal until the maximum value of the three-phase current of the motor is greater than the current threshold of the motor, stop sending the PWM signal to the inverter, and record the pulse width of the PWM signal at this time as the second pulse width of the PWM signal. The specific functions and processing of the control unit 104 are also shown in step S230.

[0180] The control unit 104 is also specifically configured to send a PWM signal to the inverter in the third working state, the fourth working state, the fifth working state, and the sixth working state to turn on the inverter, and obtain the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal in sequence. The first pulse width of the PWM signal is such as pulse width T1, the second pulse width of the PWM signal is such as pulse width T2, the third pulse width of the PWM signal is such as pulse width T3, the fourth pulse width of the PWM signal is such as pulse width T4, the fifth pulse width of the PWM signal is such as pulse width T5, and the sixth pulse width of the PWM signal is such as pulse width T6. The specific functions and processing of the control unit 104 can also be seen in step S240.

[0181] The control unit 104 is further configured to delay for a period of time until the acquired three-phase current of the motor is 0, and then determine the minimum pulse width among the first pulse width of the PWM signal, the second pulse width of the PWM signal, the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal, so as to update the initial PWM carrier cycle and obtain the current PWM carrier cycle. The specific functions and processing of the control unit 104 are also shown in step S250.

[0182] Figure 7 This is a simplified structural diagram of the equivalent circuit of a permanent magnet synchronous motor. Figure 7 As shown in FIG. 1 , the simplified equivalent circuit of the permanent magnet synchronous motor includes: a power supply, a switch S, a diode D, a resistor R and an inductor Lbc. The power supply voltage is v_dc. The positive electrode of the power supply is connected to the negative electrode of the power supply through the switch S, the resistor R and the inductor Lbc; the negative electrode of the power supply is grounded GND. The anode of the diode D is connected to the common terminal between the switch S and the resistor R; the cathode of the diode D is grounded GND. The resistance value of the resistor R is R=2Rs, where Rs is the resistance value of the motor stator resistance.

[0183] like Figure 6 As shown, disconnect the motor phase A, connect the B and C phases to the positive and negative terminals of the DC power supply respectively, and fix the motor rotor. At this time, the system is simplified to an RL circuit, that is, Figure 7 As shown. The power supply voltage v_dc is the bus voltage of the motor controller, the resistance R is twice the stator resistance Rs of the motor, and the inductance Lbc is the stator line inductance. When the switch S is closed, the voltage u and current i in the RL circuit satisfy:

[0184]

[0185] Among them, L line is the inductance value of the stator line inductance.

[0186] Because the stator resistance of a high-power motor is small, when the current is not large, R*i can be ignored, and the above formula can be simplified to:

[0187]

[0188] From this we can get:

[0189] L line =∫udt / i (3)

[0190] That is, the inductance L line It is equal to the integral of the voltage u divided by the inductance L line The current i in, when the input voltage U is constant, the above formula can be transformed into:

[0191] L line =U*t / i (4)

[0192] At this time, the inductance L line The current i and voltage U in the equation are in a linear relationship. This linear relationship only holds true when the current i is very small, i.e., in the initial stage of the RL inertial response.

[0193] Where R is the resistance value in the simplified equivalent circuit of the motor, which is twice the stator resistance Rs of the motor; u is the total load voltage in the equivalent circuit; i is the current flowing in the equivalent circuit; L line is the line inductance, that is Figure 7 L shown in bc ; t is the time of the initial stage of RL inertial response.

[0194] Figure 8 Figure 1 is a flow chart of the permanent magnet synchronous motor parameter identification method. Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method includes:

[0195] Step 1: Initialize all parameter variables, set the PWM carrier period, and set the rated current I of the permanent magnet synchronous motor. e_motor Calculate the current threshold I threshold , then execute step 2. According to the rated current I of the permanent magnet synchronous motor e_motor Calculate the current threshold I threshold The way is as follows:

[0196] I threshold =0.8*I e_motor (5).

[0197] Step 2: Enable PWM output, perform three-phase current sampling, and conduct the inverter according to the first working state (A+B-) to perform pulse width detection and adjustment. When the maximum value of the three-phase current is greater than the set current threshold I thresholdWhen the PWM output is turned off, the pulse width T1 at this time is recorded, and then step 3 is executed. Among them, the first working state (A+B-) is that the upper tube of phase A is turned on and the lower tube is turned off, the upper tube of phase B is turned off and the lower tube is turned on, and both the upper and lower tubes of phase C are turned off.

[0198] Step 3, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the second working state (A-B+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T2 at this time, and then execute step 4. Among them, there are two working states (A-B+), that is, the upper tube of phase A is turned off and the lower tube is turned on, the upper tube of phase B is turned on and the lower tube is turned off, and the upper and lower tubes of phase C are turned off.

[0199] Step 4: Sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the third working state (B+C-), and perform pulse width detection and adjustment. When the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T3 at this time, and then execute step 5. Among them, the third working state (B+C-), that is, the upper and lower tubes of phase A are turned off, the upper tube of phase B is turned on and the lower tube is turned off, and the upper tube of phase C is turned off and the lower tube is turned on.

[0200] Step 5, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the fourth working state (B-C+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T4 at this time, and then execute step 6. Among them, the fourth working state (B-C+) is that both the upper and lower tubes of phase A are turned off, the upper tube of phase B is turned off and the lower tube is turned on, and the upper tube of phase C is turned on and the lower tube is turned off.

[0201] Step 6, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the fifth working state (C+A-), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T5 at this time, and then execute step 7. Among them, the fifth working state (C+A-), that is, the upper tube of phase A is turned off and the lower tube is turned on, the upper and lower tubes of phase B are turned off, and the upper tube of phase C is turned on and the lower tube is turned off.

[0202] Step 7, sample the three-phase current, delay for a period of time (wait for the current to return to 0), and conduct the inverter according to the sixth working state (C-A+), perform pulse width detection and adjustment, and when the maximum value of the three-phase current is greater than the set current threshold, turn off the PWM output, record the pulse width T6 at this time, and then execute step 8. Among them, the sixth working state (C-A+) is that the upper tube of phase A is turned on and the lower tube is turned off, the upper and lower tubes of phase B are turned off, and the upper tube of phase C is turned off and the lower tube is turned on.

[0203] Step 8: Delay for a while until the current returns to 0, select the minimum pulse width among the six pulse widths as the pulse width T of the PWM wave, that is, T=min(T1, T2, T3, T4, T5, T6); set T as the period of the PWM carrier, and then execute step 9.

[0204] By Figure 7 From the description, it can be seen that in the simplified equivalent circuit of the motor, when the current is not large, especially when the input voltage is constant, the inductor current and voltage show a linear relationship. When the voltage pulse width is small, the current basically changes linearly. When the current is disconnected, the current slowly decreases; Steps 2 to 7 are respectively in accordance with the preset conduction state, so that the six bridge arms of the inverter are turned on in the preset manner, achieving the same Figure 7 The simplified RL circuit of the system described in the figure is used to determine the minimum pulse width T of the PWM wave. Since the existence of stray inductance, parasitic inductance, stray capacitance, parasitic capacitance, etc. in the whole system will cause the time when the maximum current in the three-phase current reaches the set threshold current to be inconsistent, that is, the PWM wave pulse width time is inconsistent, so steps 2 to 7 are to eliminate the influence of stray inductance, parasitic inductance, stray capacitance, parasitic capacitance, etc. on the line inductance in the system, and the minimum pulse width T is the required pulse width. The delay of each step is to make the current in the circuit return to 0, that is, there is only a single current generated by the wave in the circuit each time.

[0205] In the scheme of the present invention, when the motor is stationary, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the six preset conduction modes, and the pulse width is adjusted according to the output current. When the maximum value of the three-phase current is greater than the current limit value, the PWM output is turned off, and the pulse width is recorded to obtain the minimum value of the six pulse widths; this minimum pulse width is used as the pulse width of the next six PWM waves, and then the line current of the motor is obtained, and the line inductance of the permanent magnet synchronous motor is calculated to calculate the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0206] The control unit 104 is also configured to control the motor controller to send a drive signal to the drive system of the motor again according to the current PWM carrier cycle, that is, to send a PWM signal to the inverter again, and to control the upper bridge arm and lower bridge arm of the A-phase bridge arm, the upper bridge arm and lower bridge arm of the B-phase bridge arm, and the upper bridge arm and lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle. The specific functions and processing of the control unit 104 are also shown in step S130.

[0207] In some embodiments, after the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state. The line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current, and a sixth line current, wherein the first line current is such as the line current I ab , the second line current is the line current I ba 、The third line current is the line current I bc 、The fourth line current is the line current I cb 、The fifth line current is the line current I ca 、The sixth line current is the line current I ac The control unit 104 sends a PWM signal to the inverter again, and controls the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, including:

[0208] The control unit 104 is further configured to send a PWM signal to the inverter in the first working state to turn on the inverter, stop sending the PWM signal to the inverter after one current PWM carrier cycle, and calculate the line current of the motor based on the three-phase current of the motor obtained at this time as the first line current. The specific functions and processing of the control unit 104 are also shown in step S310.

[0209] The control unit 104 is further configured to send a PWM signal to the inverter to turn on the inverter in the second working state after delaying three current PWM carrier cycles, and stop sending the PWM signal to the inverter after one current PWM carrier cycle, and calculate the line current of the motor based on the three-phase current of the motor obtained at this time as the second line current. The specific functions and processing of the control unit 104 are also shown in step S320.

[0210] The control unit 104 is further configured to sequentially send PWM signals to the inverter in the third working state, the fourth working state, the fifth working state, and the sixth working state to turn on the inverter, and sequentially obtain the third line current, the fourth line current, the fifth line current, and the sixth line current to obtain the line current of the motor. The specific functions and processing of the control unit 104 are also shown in step S330.

[0211] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes:

[0212] Step 9: Sample the three-phase current, and turn on the inverter according to the first working state (A+B-). After a time T, turn off the PWM output and calculate the line current I ab , then proceed to step 10.

[0213] Step 10: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the second working state (A-B+). After one T time, turn off the PWM output and calculate the line current I ba , then proceed to step 11.

[0214] Step 11: Sample the three-phase current, delay for 3 T times (wait for the current to return to 0), and turn on the inverter according to the third working state (B+C-). After a T time, turn off the PWM output and calculate the line current I bc , then proceed to step 12.

[0215] Step 12: Sample the three-phase current, delay for 3 T times (wait for the current to return to 0), and turn on the inverter according to the fourth working state (B-C+). After a T time, turn off the PWM output and calculate the line current L cb , then proceed to step 13.

[0216] Step 13: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the fifth working state (C+A-). After one T time, turn off the PWM output and calculate the line current I ca , then proceed to step 14.

[0217] Step 14: Sample the three-phase current, delay for 3 T time (wait for the current to return to 0), and turn on the inverter according to the sixth working state (C-A+). After one T time, turn off the PWM output and calculate the line current I ac , then proceed to step 15.

[0218] Steps 9 to 14 are to further obtain the line current I in six simplified equivalent circuits after the minimum pulse width of the PWM wave is determined. ab ,I ba ,I bc ,I cb ,I ca ,I ac , and then calculate the motor parameters cross-axis and direct-axis inductance L through the formula q , L d With position angle θ e .

[0219] In the scheme of the present invention, after determining the pulse width of the next six PWM waves, the inverter is controlled in turn to turn on the corresponding two-phase bridge arms according to the preset six conduction modes, the line current is recorded, and the line inductance of the permanent magnet synchronous motor is calculated to obtain the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0220] The control unit 104 is further configured to calculate the motor parameters to be determined according to the line current of the motor. The specific functions and processing of the control unit 104 are also shown in step S140.

[0221] The scheme of the present invention proposes a parameter identification scheme for a permanent magnet synchronous motor. When the motor is stationary, the inverter is controlled in sequence to turn on the corresponding two-phase bridge arms according to six preset conduction modes, and the pulse width is adjusted according to the output current. When the maximum value of the three-phase current is greater than the current limit value, the pulse width modulation (PWM) output is turned off, and the pulse width is recorded to obtain the minimum value of the six pulse widths; this minimum pulse width is used as the pulse width of the next six PWM waves, and the inverter is controlled in sequence to turn on the corresponding two-phase bridge arms according to the six preset conduction modes, and the line current is recorded. The line inductance of the permanent magnet synchronous motor is calculated to calculate the parameters to be identified, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0222] In some embodiments, the parameters of the motor include the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor; the control unit 104 calculates the required parameters of the motor according to the line current of the motor, that is, according to the line current of the motor, calculates the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor as the required parameters of the motor, including:

[0223] The control unit 104 is further configured to calculate the line inductance of the motor according to the line current of the motor. The specific functions and processing of the control unit 104 are also shown in step S410.

[0224] In some embodiments, the line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current, wherein the first line current is the line current I ab , the second line current is the line current I ba 、The third line current is the line current I bc 、The fourth line current is the line current I cb 、The fifth line current is the line current I ca 、The sixth line current is the line current L ac The control unit 104, the line inductance of the motor includes: a first line inductance, a second line inductance and a third line inductance; according to the line current of the motor, the line inductance of the motor is calculated, including: the control unit 104 is further configured to calculate according to the line current of the motor using the following formula to obtain the line inductance of the motor:

[0225]

[0226] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, U dc is the bus voltage on the input side of the inverter, I ab is the first line current, I ba is the second line current, I bc is the third line current, I cb is the fourth line current, I ca is the fifth line current, I ac is the sixth line current, R S is the stator resistance of the motor, ΔT is the delay period, k1 is the first calculation coefficient (preferably k1 is 2), k2 is the second calculation coefficient (preferably k2 is 0.5);

[0227] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes: step 15, calculating the line inductance L in the natural coordinate system ab , L bc , L ca , then proceed to step 16.

[0228] Depend on Figure 7The simplified equivalent circuit of the permanent magnet synchronous motor shown in the figure shows that the line inductance L line :

[0229]

[0230] Among them, U line is the inductance L bc The voltage, I line is the inductance L bc The current is Δt, which is the delay period.

[0231] Therefore, the inductance L in the natural coordinate system is ab , L bc , L ca The expression is:

[0232]

[0233] Wherein, line current:

[0234]

[0235] In the scheme of the present invention, after obtaining the line current of the motor, the line inductance of the motor is calculated according to the line current of the motor to serve as a basis for calculating the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor. This can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0236] The control unit 104 is further configured to calculate the shaft inductance of the motor according to the line inductance of the motor; the shaft inductance of the motor includes: the quadrature-axis inductance and the direct-axis inductance of the motor. The specific functions and processing of the control unit 104 are also shown in step S420.

[0237] The control unit 104 is further configured to calculate the position angle of the motor according to the shaft inductance of the motor, and use the calculated position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor as the parameters of the motor to be determined. The specific functions and processing of the control unit 104 are also shown in step S430.

[0238] In the scheme of the present invention, after obtaining the line current of the motor, the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor are calculated according to the line current of the motor as the parameters of the motor to be determined. This can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters, and ensure the accuracy of the motor parameter acquisition.

[0239] In some implementations, the control unit 104 calculates the shaft inductance of the motor according to the line inductance of the motor, and calculates the position angle of the motor according to the shaft inductance of the motor, including: the control unit 104 is further configured to calculate the shaft inductance of the motor and the position angle of the motor according to the following formula according to the line inductance of the motor:

[0240]

[0241] Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, L d is the quadrature axis inductance of the motor, L q is the direct axis inductance of the motor, θ e is the position angle of the motor, k3 is the third calculation coefficient (preferably k3 is 2).

[0242] like Figure 8 As shown, the specific implementation logic of the permanent magnet synchronous motor parameter identification method also includes: step 16, calculating the shaft inductance L d , L q , then proceed to step 17.

[0243] Line inductance L in natural coordinate system ab , L bc , L ca and shaft inductance L d , L q The relationship between them is as follows:

[0244]

[0245] Let A = L d +L q , B=L d -L q , L0=L ab -A, Then we have:

[0246]

[0247] Detailed calculation:

[0248]

[0249] Step 17: Calculate the position angle θ e .

[0250] make Then we have:

[0251]

[0252] Detailed calculation:

[0253]

[0254] Among these parameters, θ e That is, the motor position angle to be identified, L q , L d This is the desired AC and DC axis inductance of the motor.

[0255] Among them, I e_motor is the rated current of the motor, I threshold is the current threshold that the motor current is set to reach; T1~T6 are the time required for the maximum current in the three-phase current to be greater than the set current threshold under the six working conditions, that is, the PWM wave pulse width under the six working conditions; T is the minimum pulse width among the six pulse widths of T1~T6; I ab ,I ba ,I bc ,I cb ,I ca ,I ac are the line currents sampled in steps 9 to 14 respectively; L ab , L bc , L ca are the line inductance of the motor; U dc is the bus voltage of the motor controller; L d , L q They are the motor direct-axis and quadrature-axis inductances, Theta_t, θ e is the motor position angle; A, B, L0, L1, M0, M1, M2 are the parameters to be identified for the convenience of calculation: the AC and DC axis inductances Lq, Ld and the position angle θ e The defined intermediate variables have no special meaning.

[0256] In the scheme of the present invention, the shaft inductance of the motor is calculated based on the line inductance of the motor, and the position angle of the motor is calculated based on the shaft inductance of the motor, which can improve the identification accuracy of the permanent magnet synchronous motor parameters and the accuracy of the identification parameters and ensure the accuracy of the motor parameter acquisition.

[0257] The scheme of the present invention proposes a permanent magnet synchronous motor parameter identification scheme, which is not only applicable to the field of electric vehicles, but also to CNC machine tools, machinery manufacturing, industrial robots, aerospace and other permanent magnet synchronous motor application occasions. The scheme of the present invention can improve the identification accuracy of permanent magnet synchronous motor parameters and the accuracy of identification parameters, which is conducive to the rapid matching of the motor controller and the permanent magnet synchronous motor, and is conducive to the precise control of the motor, ensuring the efficient operation of the motor, and improving the robustness of the control system. The method simplifies the calculation process, is easy to implement, reliable in control, easy to implement, and convenient for promotion and use.

[0258] Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0259] According to an embodiment of the present invention, a motor corresponding to the device for determining the parameters of the motor is also provided. The motor may include: the device for determining the parameters of the motor described above.

[0260] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0261] According to an embodiment of the present invention, a computer program product corresponding to a motor is also provided, comprising a computer program, and when the computer program is executed by a processor, the steps of the method for determining parameters of the motor described above are implemented.

[0262] Since the processing and functions implemented by the product of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned motor, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0263] According to an embodiment of the present invention, a storage medium corresponding to a method for determining motor parameters is also provided, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the method for determining motor parameters described above.

[0264] Since the processing and functions implemented by the storage medium of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0265] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0266] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A method for determining parameters of a motor, characterized in that: The motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first switch tube and the fourth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, and are used to power the U-phase winding in the three-phase winding of the motor, the third switch tube and the sixth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and are used to power the V-phase winding in the three-phase winding of the motor, the fifth switch tube and the second switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm, and are used to power the W-phase winding in the three-phase winding of the motor; the method for determining the parameters of the motor includes: Obtaining a preset PWM carrier cycle as an initial PWM carrier cycle; obtaining a rated current of the motor; and, when the inverter is turned on, obtaining a three-phase current of the motor; When the motor is stationary, a PWM signal is sent to the inverter according to the initial PWM carrier cycle to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle to obtain a current PWM carrier cycle; According to the current PWM carrier cycle, a PWM signal is sent to the inverter again, and the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are controlled again to be turned on in a preset manner, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle; The required parameters of the motor are calculated based on the line current of the motor.

2. The method for determining the parameters of a motor according to claim 1, characterized in that: The upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, which is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm of the inverter are controlled to make the inverter in the first working state, the second working state, the third working state, the fourth working state, the fifth working state and the sixth working state in sequence; wherein, The first working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper bridge arm switch tube of the B-phase bridge arm is turned off and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm are both turned off; The second working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube of the B-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off, and the upper and lower bridge arm switch tubes of the C-phase bridge arm are both turned off; The third working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned on and the lower bridge arm switch tube is turned off, and the upper bridge arm switch tube of the C phase bridge arm is turned off and the lower bridge arm switch tube is turned on; The fourth working state is: the upper bridge arm switch tube and the lower bridge arm switch tube of the A phase bridge arm of the inverter are both turned off, the upper bridge arm switch tube of the B phase bridge arm is turned off, and the lower bridge arm switch tube is turned on, and the upper bridge arm switch tube of the C phase bridge arm is turned on, and the lower bridge arm switch tube is turned off; The fifth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned off, and the lower bridge arm switch tube is turned on, the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned on, and the lower bridge arm switch tube is turned off; The sixth working state is: the upper bridge arm switch tube of the A-phase bridge arm of the inverter is turned on and the lower bridge arm switch tube is turned off, the upper and lower bridge arm switch tubes of the B-phase bridge arm are both turned off, and the upper bridge arm switch tube of the C-phase bridge arm is turned off and the lower bridge arm switch tube is turned on.

3. The method for determining the parameters of a motor according to claim 1 or 2, characterized in that: After the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; Sending a PWM signal to the inverter to control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to: update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, and obtain the current PWM carrier cycle, including: Determining a current threshold of the motor according to the rated current of the motor; Sending a PWM signal to the inverter in the first working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the three-phase current of the motor obtained is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time as the first pulse width of the PWM signal; Delaying for a period of time until the acquired three-phase current of the motor is 0, sending a PWM signal to the inverter according to the second working state to turn on the inverter, and then adjusting the pulse width of the PWM signal until the maximum value of the acquired three-phase current of the motor is greater than the current threshold of the motor, stopping sending the PWM signal to the inverter, and recording the pulse width of the PWM signal at this time as the second pulse width of the PWM signal; In this way, a PWM signal is sent to the inverter in the third working state, the fourth working state, the fifth working state and the sixth working state in sequence to turn on the inverter, and a third pulse width of the PWM signal, a fourth pulse width of the PWM signal, a fifth pulse width of the PWM signal and a sixth pulse width of the PWM signal are obtained in sequence; Delay for a period of time until the acquired three-phase current of the motor is 0, and then determine the minimum pulse width among the first pulse width of the PWM signal, the second pulse width of the PWM signal, the third pulse width of the PWM signal, the fourth pulse width of the PWM signal, the fifth pulse width of the PWM signal, and the sixth pulse width of the PWM signal to update the initial PWM carrier period and obtain the current PWM carrier period.

4. The method for determining parameters of a motor according to claim 1 or 2, characterized in that: After the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter are turned on in a preset manner, the inverter can be in any one of the first working state, the second working state, the third working state, the fourth working state, the fifth working state, and the sixth working state; The line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current; Sending a PWM signal to the inverter again, and controlling the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, including: Sending a PWM signal to the inverter in the first working state to turn on the inverter, stopping sending the PWM signal to the inverter after one current PWM carrier cycle, and calculating the line current of the motor based on the three-phase current of the motor obtained at this time as the first line current; After a delay of three current PWM carrier cycles, a PWM signal is sent to the inverter in the second working state to turn on the inverter, and after one current PWM carrier cycle, the PWM signal is stopped from being sent to the inverter, and a line current of the motor is calculated based on the three-phase current of the motor obtained at this time as the second line current; In this way, PWM signals are sent to the inverter in the third working state, the fourth working state, the fifth working state and the sixth working state in sequence to turn on the inverter, and the third line current, the fourth line current, the fifth line current and the sixth line current are obtained in sequence to obtain the line current of the motor.

5. The method for determining parameters of a motor according to claim 1 or 2, characterized in that: The parameters of the motor include the position angle of the motor, and the quadrature-axis inductance and direct-axis inductance of the motor; Calculating the required parameters of the motor according to the line current of the motor includes: Calculating the line inductance of the motor according to the line current of the motor; The shaft inductance of the motor is calculated based on the line inductance of the motor; the shaft inductance of the motor includes: the quadrature-axis inductance and the direct-axis inductance of the motor; The position angle of the motor is calculated based on the shaft inductance of the motor; and the calculated position angle of the motor, as well as the quadrature-axis inductance and direct-axis inductance of the motor are used as the parameters of the motor to be determined.

6. The method for determining parameters of a motor according to claim 5, characterized in that: in, The line current of the motor includes: a first line current, a second line current, a third line current, a fourth line current, a fifth line current and a sixth line current; The line inductance of the motor includes: a first line inductance, a second line inductance and a third line inductance; Calculating the line inductance of the motor according to the line current of the motor includes: According to the line current of the motor, the line inductance of the motor is calculated using the following formula: Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, U dc is the bus voltage on the input side of the inverter, I ab is the first line current, I ba is the second line current, I bc is the third line current, I cb is the fourth line current, I ca is the fifth line current, I ac is the sixth line current, R S is the stator resistance of the motor, ΔT is the delay period, k1 is the first calculation coefficient, and k2 is the second calculation coefficient; and / or, Calculating the shaft inductance of the motor according to the line inductance of the motor, and calculating the position angle of the motor according to the shaft inductance of the motor, including: According to the line inductance of the motor, the shaft inductance of the motor and the position angle of the motor are calculated using the following formula: Among them, L ab , L bc , L ca are the first line inductance, the second line inductance and the third line inductance of the line inductance of the motor, L d is the quadrature axis inductance of the motor, L q is the direct axis inductance of the motor, θ e is the position angle of the motor, and k3 is the third calculation coefficient.

7. A device for determining parameters of a motor, characterized in that: The motor has a drive system and a three-phase winding; the drive system of the motor has an inverter, the inverter has a three-phase full-bridge inverter bridge composed of a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, the first switch tube and the fourth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the A-phase bridge arm, and are used to power the U-phase winding in the three-phase winding of the motor, the third switch tube and the sixth switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the B-phase bridge arm, and are used to power the V-phase winding in the three-phase winding of the motor, the fifth switch tube and the second switch tube are the upper bridge arm switch tube and the lower bridge arm switch tube of the C-phase bridge arm, and are used to power the W-phase winding in the three-phase winding of the motor; the motor parameter determination device includes: an acquisition unit configured to acquire a preset PWM carrier cycle as an initial PWM carrier cycle; acquire a rated current of the motor; and, when the inverter is turned on, acquire a three-phase current of the motor; A control unit is configured to send a PWM signal to the inverter according to the initial PWM carrier cycle when the motor is stationary, and control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner, so as to update the initial PWM carrier cycle in combination with the rated current of the motor and the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle, and obtain a current PWM carrier cycle; The control unit is further configured to send a PWM signal to the inverter again according to the current PWM carrier cycle, and control the upper bridge arm and the lower bridge arm of the A-phase bridge arm, the upper bridge arm and the lower bridge arm of the B-phase bridge arm, and the upper bridge arm and the lower bridge arm of the C-phase bridge arm of the inverter to be turned on in a preset manner again, so as to: calculate the line current of the motor according to the three-phase current of the motor obtained when the inverter is controlled according to the initial PWM carrier cycle; The control unit is further configured to calculate the required parameters of the motor according to the line current of the motor.

8. A motor, characterized in that: include: The device for determining parameters of a motor as claimed in claim 7.

9. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the method for determining parameters of a motor according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for determining parameters of a motor according to any one of claims 1 to 6 are implemented.

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