A deadbeat torque and flux control method for permanent magnet synchronous motor

Abstract

The present invention relates to the technical field of motor control production, and discloses a method for controlling the zero-beat torque and flux linkage of a permanent magnet synchronous motor, comprising the following steps: S1, collecting three-phase stator current, three-phase stator voltage, speed and angle information; S2, obtaining speed error information and obtaining an electromagnetic torque reference value; S3, calculating the stator flux linkage and the motor electromagnetic torque to obtain a torque error; S4, obtaining a flux linkage error; S5, calculating the amplitude and angle of a reference voltage vector; S6, synthesizing the voltage vector through an SVPWM module and inputting it into the motor; the present invention can quickly and accurately calculate a voltage vector that makes the torque and flux linkage errors simultaneously zero, wherein the angle of the reference voltage vector meets the requirement that the torque error is zero, and the amplitude of the reference voltage vector meets the requirement that the flux linkage error is zero, thereby realizing control of the torque flux linkage, avoiding the torque pulsation problem caused by flux linkage coupling, and the calculation of the voltage vector is relatively simple, and no complex coordinate transformation is required in the entire technical process.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a deadbeat torque flux control method for a permanent magnet synchronous motor. Background Art

[0002] Currently, most of the control of motors is focused on torque control, while the control of stator flux is neglected. The calculation of torque requires the use of stator flux, so there is a coupling relationship between stator flux and torque. If a large amount of pulsation occurs in the stator flux, the torque control performance will deteriorate. The current method for simultaneously controlling torque and flux is zero-beat torque flux control. The most important step in zero-beat control is the calculation of the reference voltage vector. In traditional zero-beat torque flux control, the method for calculating the reference voltage vector is through torque Rings and magnetic links The loop obtains the reference voltage vector, The introduction of the ring loses the excellent dynamic performance of torque control. The ring parameter tuning is more complicated. In addition, some scholars have used coordinate transformation to calculate the and two-phase rotating coordinate system The calculation formula of the reference voltage vector is derived below. This method requires complicated coordinate transformation and will bring huge computational burden to the controller. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In order to solve the problem of complex and tedious reference voltage vector calculation in the existing technology for zero-beat torque flux control, the present invention is based on the idea of ​​zero-beat torque flux control, with the goal of simultaneously controlling torque and flux, and proposes a reference voltage vector calculation method established in a three-phase stationary coordinate system. The present invention uses the torque zero-beat method to obtain the angle of the reference voltage vector, and uses the flux zero-beat method to obtain the amplitude of the reference voltage vector. The reference voltage vector calculation method proposed by the present invention does not require complex and tedious coordinate transformation operations, and can simultaneously control the torque and flux of the motor.

[0005] (2) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0007] A method for controlling deadbeat torque and flux linkage of a permanent magnet synchronous motor comprises the following steps:

[0008] S1. Collect three-phase stator current through current sensor The three-phase stator voltage is reconstructed by the voltage value collected by the DC bus voltage sensor and the inverter switching state. , the speed obtained by the photoelectric encoder With angle information ;

[0009] S2, set the speed value The actual speed value obtained by the photoelectric encoder Compare and get the speed error information, the speed error is input into the speed The loop obtains the electromagnetic torque reference value ;

[0010] S3. Calculate the stator flux and motor electromagnetic torque , and the estimated electromagnetic torque value With the speed ring The electromagnetic torque obtained by the controller Compare with the given value to get the torque error;

[0011] S4, set the given magnetic flux value and estimated magnetic linkage value Compare and get the flux linkage error;

[0012] S5. Bring the torque error, flux error, speed, motor angle and other parameters into the voltage vector calculation module to calculate the amplitude of the reference voltage vector and angles ;

[0013] S6. The voltage vector is synthesized through the SVPWM module and input into the motor to control the torque and flux of the motor.

[0014] Preferably, the stator flux in S3 and motor electromagnetic torque The calculation method is:

[0015] In the three-phase stationary coordinate system, the stator current and stator flux The relationship between them is:

[0016] (1-1)

[0017] In the three-phase stationary coordinate system, the stator flux and motor electromagnetic torque The relationship between is:

[0018] (1-2)

[0019] in is the electromagnetic torque; is the number of permanent magnet pole pairs; is the stator flux; is the stator current, is the three-phase stator voltage.

[0020] Preferably, the reference voltage vector angle in S5 is calculated as follows:

[0021] Differentiating the electromagnetic torque formula (1-2) yields:

[0022] (1-3)

[0023] in, is the reference voltage vector, 、 are the resistance and inductance of the motor, is the magnetic flux of the rotor permanent magnet, is the motor speed;

[0024] Calculate the stator flux equation according to formula (1-3):

[0025] (1-4)

[0026] Substituting the stator flux equation (1-4) into equation (1-3), the electromagnetic torque differential equation is:

[0027] (1-5)

[0028] According to formula (1-5), the angle between the voltage vector and the d-axis can be obtained for:

[0029] (1-6)

[0030] The discretized equation of torque is:

[0031] (1-7)

[0032] Using torque deadbeat control:

[0033] (1-8)

[0034] in, is the torque reference value;

[0035] Substituting formula (1-8) into formula (1-5) yields:

[0036] (1-9)

[0037] Substituting equation (1-9) into equation (1-6) yields the angle between the voltage vector and the d-axis: for:

[0038] (1-10)

[0039] The formula for calculating the motor torque angle is:

[0040] (1-11)

[0041] The angular relationship between the torque angle and the voltage vector is:

[0042] (1-12).

[0043] Preferably, the voltage vector amplitude in S5 is calculated as follows:

[0044] Adopt flux zero beat control, that is, let the flux prediction value With the flux linkage given value equal:

[0045] (1-13)

[0046] Usually the stator resistance voltage drop is small and can be ignored, so equation (1-1) can be changed to:

[0047] (1-14)

[0048] Substituting formula (1-13) into formula (1-14) yields:

[0049] (1-15)

[0050] The stator flux amplitude relationship is:

[0051] (1-16)

[0052] The relationship between the amplitudes before and after the flux change is:

[0053] (1-17)

[0054] Because a control cycle is very small, The value of ( The value is usually ) is much smaller than other values ​​and can be ignored. The amplitude of the reference voltage vector can be derived from formula (1-17):

[0055] (1-18)

[0056] Substituting equations (1-11), (1-12), and (1-18) into equation (1-10), we can obtain the angle and amplitude of the voltage vector as follows:

[0057] (1-19)

[0058] The specific reference voltage vector angle calculation formula is:

[0059] (1-20)

[0060] Where A, B, C, and D represent:

[0061]

[0062] Substituting (1-20), (1-11), and (1-12) into (1-18) yields the specific reference voltage vector amplitude calculation formula:

[0063] (1-21).

[0064] (3) Beneficial effects

[0065] Compared with the prior art, the present invention provides a method for controlling the torque flux linkage of a permanent magnet synchronous motor without a beat, which has the following beneficial effects:

[0066] Compared with the existing technology, the present invention can quickly and accurately calculate the voltage vector that makes the torque and flux errors simultaneously zero, wherein the angle of the reference voltage vector meets the requirement of zero torque error, and the amplitude of the reference voltage vector meets the requirement of zero flux error, thereby realizing simultaneous control of torque and flux, avoiding the torque pulsation problem caused by flux coupling, the calculation of the voltage vector is relatively simple, and the entire technical process does not require complex coordinate transformation, and can simultaneously control the torque and flux of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is the block diagram of the deadbeat torque flux control;

[0068] Figure 2 is the coordinate relationship diagram of stator flux and reference voltage vector;

[0069] Figure 3 It is the principle diagram of magnetic flux change;

[0070] Figure 4 This is the principle block diagram of voltage vector calculation. DETAILED DESCRIPTION

[0071] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying 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 efforts are within the scope of protection of the present invention.

[0072] Reference Figure 1-4 The present invention also provides a permanent magnet synchronous motor zero-beat torque flux control method, including a speed PI controller, a voltage vector calculation module, an SVPWM module, a current detection module, a phase voltage calculation module, a torque and flux estimation module, a position and speed detection module, a three-phase two-level inverter and a permanent magnet synchronous motor. The control block diagram is shown as follows: Figure 1 The specific steps are as follows:

[0073] S1. Collect three-phase stator current through current sensor The three-phase stator voltage is reconstructed by the voltage value collected by the DC bus voltage sensor and the inverter switching state. , the speed obtained by the photoelectric encoder With angle information ;

[0074] S2, set the speed value The actual speed value obtained by the photoelectric encoder Compare and get the speed error information, the speed error is input into the speed The loop obtains the electromagnetic torque reference value ;

[0075] S3. Calculate the stator flux and motor electromagnetic torque , and the estimated electromagnetic torque value With the speed ring The electromagnetic torque obtained by the controller Compare with the given value to get the torque error;

[0076] In the three-phase stationary coordinate system, the stator current and stator flux The relationship between them is:

[0077] (1-1);

[0078] In the three-phase stationary coordinate system, the stator flux and motor electromagnetic torque The relationship between is:

[0079] (1-2);

[0080] According to (1-1) and (1-2) stator flux and motor electromagnetic torque

[0081] in is the electromagnetic torque; is the number of permanent magnet pole pairs; is the stator flux; is the stator current, is the three-phase stator voltage, and the relationship between the stator flux and the voltage vector coordinates is as follows: Figure 2 As shown in the figure, is the angle between the reference voltage vector and the d-axis; is the angle between the stator flux and the rotor flux of the motor, which represents the torque angle of the motor; is the angle between the voltage vector and the stator flux; is the angle before and after the magnetic flux changes; is the motor rotor angle; is the angle of the reference voltage vector.

[0082] S4, set the given magnetic flux value and estimated magnetic linkage value Compare and get the flux linkage error;

[0083] S5. Bring the torque error, flux error, speed, motor angle and other parameters into the voltage vector calculation module to calculate the amplitude of the reference voltage vector and angles ;

[0084] The angle of the reference voltage vector is calculated as follows:

[0085] Differentiating the electromagnetic torque formula (1-2) yields:

[0086] (1-3)

[0087] in, is the reference voltage vector, 、 are the resistance and inductance of the motor, is the magnetic flux of the rotor permanent magnet, is the motor speed;

[0088] Calculate the stator flux equation according to formula (1-3):

[0089] (1-4)

[0090] Substituting the stator flux equation (1-4) into equation (1-3), the electromagnetic torque differential equation is:

[0091] (1-5)

[0092] According to formula (1-5), the angle between the voltage vector and the d-axis can be obtained for:

[0093] (1-6)

[0094] in is the magnitude of the voltage vector;

[0095] The discretized equation of torque is:

[0096] (1-7)

[0097] Using torque deadbeat control:

[0098] (1-8)

[0099] in, is the torque reference value;

[0100] Substituting formula (1-8) into formula (1-5) yields:

[0101] (1-9)

[0102] Substituting equation (1-9) into equation (1-6) yields the angle between the voltage vector and the d-axis: for:

[0103] (1-10)

[0104] The formula for calculating the motor torque angle is:

[0105] (1-11)

[0106] according to Figure 2 It can be seen that the angular relationship between the torque angle and the voltage vector is:

[0107] (1-12)

[0108] The method for calculating the reference voltage vector amplitude through flux linkage deadbeat is as follows:

[0109] Adopt flux zero beat control, that is, let the flux prediction value With the flux linkage given value equal:

[0110] (1-13)

[0111] in, is the predicted value of magnetic linkage, is the given value of magnetic linkage;

[0112] Usually the stator resistance voltage drop is small and can be ignored, so equation (1-1) can be changed to:

[0113] (1-14)

[0114] Substituting formula (1-13) into formula (1-14) yields:

[0115] (1-15)

[0116] According to formula (1-15), we can get Figure 3 The stator flux variation diagram shown;

[0117] from Figure 2 The stator flux amplitude relationship can be obtained as follows:

[0118] (1-16)

[0119] according to Figure 3 The geometric relationship before and after the change of the magnetic flux can be obtained as follows:

[0120] (1-17)

[0121] Because a control cycle is very small, The value of ( The value is usually ) is much smaller than other values ​​and can be ignored. The amplitude of the reference voltage vector can be derived from formula (1-17):

[0122] (1-18)

[0123] Substituting equations (1-11), (1-12), and (1-18) into equation (1-10), we can obtain the angle and amplitude of the voltage vector as follows:

[0124] (1-19)

[0125] The specific reference voltage vector angle calculation formula is:

[0126] (1-20)

[0127] Where A, B, C, and D represent:

[0128]

[0129] Substituting (1-20), (1-11), and (1-12) into (1-18) yields the specific reference voltage vector amplitude calculation formula:

[0130] (1-21)

[0131] The specific calculation process is as follows Figure 4 shown.

[0132] S6. The voltage vector is synthesized through the SVPWM module and input into the motor to achieve zero-beat control of the motor torque and flux.

[0133] It should be noted that the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0134] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the zero-beat torque flux of a permanent magnet synchronous motor, characterized in that: The steps include: S1. Collect three-phase stator current through current sensor The three-phase stator voltage is reconstructed by collecting the voltage value obtained by the DC bus voltage sensor and the inverter switching state. , the speed is obtained by collecting the photoelectric encoder ; S2, set the speed value The actual speed value obtained by the photoelectric encoder By comparison, we can get the speed error information. The speed error is calculated by the speed The loop obtains the electromagnetic torque reference value ; S3. Calculate the stator flux and motor electromagnetic torque , and the estimated electromagnetic torque value With the speed ring The electromagnetic torque obtained by the controller Compare with the given value to get the torque error; S4, set the given magnetic linkage value and estimated magnetic linkage value Compare and get the flux linkage error; S5. Bring the torque error, flux error, speed, motor angle, stator flux, and rotor permanent magnet flux into the voltage vector calculation module to calculate the amplitude of the reference voltage vector. and angles ; The reference voltage vector angle is calculated as: Differentiating the electromagnetic torque formula yields: （1-3） in, is the reference voltage vector, 、 are the resistance and inductance of the motor, is the rotor permanent magnet flux, is the motor speed; is the number of permanent magnet pole pairs; Calculate the stator flux equation according to formula (1-3): （1-4） Substituting the stator flux equation (1-4) into equation (1-3), the electromagnetic torque differential equation is: （1-5） According to formula (1-5), the angle between the voltage vector and the d-axis can be obtained for: （1-6） The discretized equation of torque is: （1-7） in, T s Represents the control period of the controller; Using torque deadbeat control: （1-8） in, is the torque reference value; Substituting formula (1-8) into formula (1-5) yields: （1-9） Substituting equation (1-9) into equation (1-6) yields the angle between the voltage vector and the d-axis: for: （1-10） The formula for calculating the motor torque angle is: （1-11） The angular relationship between the torque angle and the voltage vector is: （1-12）； in, is the angle between the voltage vector and the d-axis, is the torque angle of the motor, is the angle between the voltage vector and the stator flux; The voltage vector amplitude is calculated as: Adopt flux zero beat control, that is, let the flux prediction value With the flux linkage given value equal: （1-13） Ignoring the stator resistance voltage drop, the stator flux equation becomes: （1-14） Substituting formula (1-13) into formula (1-14) yields: （1-15） The stator flux amplitude relationship is: （1-16） The relationship between the amplitude before and after the flux change is: （1-17） From formula (1-17), it can be deduced that the amplitude of the reference voltage vector is: （1-18） Substituting equations (1-11), (1-12), and (1-18) into equation (1-10), we can obtain the angle and amplitude of the voltage vector as follows: （1-19） in, is the motor rotor angle; The specific reference voltage vector angle calculation formula is: （1-20） Where A, B, C, and D represent: Substituting (1-20), (1-11), and (1-12) into (1-18) yields the specific reference voltage vector amplitude calculation formula: （1-21）； S6. The voltage vector is synthesized through the SVPWM module and input into the motor to control the torque and flux of the motor.

2. The method for controlling the deadbeat torque and flux linkage of a permanent magnet synchronous motor according to claim 1, wherein: The stator flux in S3 and motor electromagnetic torque The calculation method is: In the three-phase stationary coordinate system, the stator current and stator flux The relationship between them is: （1-1） In the three-phase stationary coordinate system, the stator flux and motor electromagnetic torque The relationship between is: （1-2） in is the electromagnetic torque; is the number of permanent magnet pole pairs; is the stator flux; is the stator current, is the three-phase stator voltage.

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