Position sensorless control method of dual three-phase synchronous reluctance motor

Abstract

The invention discloses a position-sensorless control method for double three-phase synchronous reluctance motors, and relates to the technical field of motor control. Establishing a motor mathematical model, and performing vector space decoupling transformation to obtain a voltage and flux linkage equation; deriving from a stator voltage equation to obtain a current and voltage model; the current model and the voltage model are combined to obtain a mixed type effective flux linkage observer; obtaining a result of dq-axis self-inductance and mutual inductance changing along with dq-axis current through finite element simulation; a mutual inductance value is introduced, dq-axis self-inductance and mutual inductance values are updated in real time through a table look-up method, position errors caused by magnetic saturation and a cross coupling effect are compensated, and an optimized mixed type effective flux linkage observer is obtained; and sending the observation result as an input signal to a phase-locked loop, and outputting the position and speed information of the motor. According to the hybrid flux linkage observer based on a current model and a voltage model, inductance nonlinear change caused by magnetic saturation and cross coupling effects is compensated on the basis, and the observation precision of the position observer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a sensorless control method for a dual three-phase synchronous reluctance motor. Background Art

[0002] Synchronous reluctance motors have the advantages of simple structure, low material cost, insensitivity to temperature rise, strong rotor robustness, high torque density and efficiency, wide speed regulation range, etc., and have been widely used in various fields. Moreover, with the expansion of the application fields of motor drives and the increase in power levels, in some occasions with low voltage, high power and high reliability requirements, multi-phase motor drive systems will have a broader application prospect.

[0003] Sensorless control technology has received extensive attention in recent years due to its advantages such as low cost, high reliability, and good potential for industrial application development. Sensorless control technology is mainly divided into the salient pole tracking method based on obtaining position information from the rotor saliency, and the fundamental frequency model method based on obtaining position information from the back electromotive force or magnetic flux linkage, which are respectively applicable to the low-speed and medium-high-speed operation of the motor.

[0004] However, due to the influence of magnetic saturation and cross-coupling effects, the magnetic field salient pole of the synchronous reluctance motor will lead or lag the geometric salient pole, and the inductance will change non-linearly with the degree of magnetic saturation and cross-coupling effects, thereby affecting the accuracy of the position observer. At present, most of the sensorless control technologies are applied to permanent magnet synchronous motors, and there is less research on the sensorless control technology for multi-phase synchronous reluctance motors. Summary of the Invention

[0005] To solve the deficiencies in the background art, the present invention provides a sensorless control method for a dual three-phase synchronous reluctance motor. For the dual three-phase synchronous reluctance motor, a hybrid flux observer based on the current model and voltage model is used, and on this basis, the non-linear change of the inductance caused by magnetic saturation and cross-coupling effects is compensated, thereby improving the observation accuracy of the position observer.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A sensorless control method for a dual three-phase synchronous reluctance motor, comprising the following steps:

[0007] Step 1: Establish a mathematical model of the dual three-phase synchronous reluctance motor, perform a vector space decoupling transformation on it, and the vector space decoupling transformation matrix used is expressed as follows:

[0008]

[0009] In the formula, θ e is the actual electrical angle of the rotor;

[0010] The vector space decoupling transformation of the voltage equation and flux linkage equation of the dual three-phase synchronous reluctance motor is expressed as follows:

[0011]

[0012] Wherein, u d , u q , u z1 , u z2 are the voltages of the corresponding sub-planes respectively, i d , i q , i z1 , i z2 are the currents of the corresponding sub-planes respectively, ψ d , ψ q , ψ z1 , ψ z2 are the flux linkages of the corresponding sub-planes respectively, L d and L q are the direct-axis inductance and quadrature-axis inductance respectively, L aa1 is the leakage inductance, R is the stator resistance, ω e is the actual electrical angular velocity of the rotor;

[0013] Step 2: The stator voltage equation of the dual three-phase synchronous reluctance motor is expressed as follows:

[0014]

[0015] Wherein, u αβ is the stator voltage, i αβ is the stator current, ψ αβ is the stator flux linkage in the stator coordinate system;

[0016] Furthermore, the stator flux linkage is expressed as follows:

[0017]

[0018] Substituting formula (3) into formula (5) to obtain another expression of the stator flux linkage as follows:

[0019] ψ αβ = ((L d - L q )i d )·(cosθ e , sinθ e ) T + L q i αβ (6)

[0020] Introduce the effective flux linkage, and the relationship between the effective flux linkage and the stator flux linkage is expressed as follows:

[0021] ψ A = ψ αβ-L q i αβ (7)

[0022] In the formula, ψ A is the effective magnetic flux linkage;

[0023] The current model and voltage model representations of the effective magnetic flux linkage are obtained as follows:

[0024]

[0025] In the formula, is the current model of the effective magnetic flux linkage, is the estimated electrical angle of the rotor, is the voltage model of the effective magnetic flux linkage, and u comp is the compensation value for the disturbance quantity encountered during the magnetic flux linkage observation process;

[0026] Step 3: Combine the current model and voltage model of the effective magnetic flux linkage. Use the calculation result of the current model as the input and the calculation result of the voltage model as the feedback. The difference between the two is adjusted to zero by a PI regulator, and the hybrid effective magnetic flux linkage observer is obtained as follows:

[0027]

[0028] In the formula, k p and k i are the proportional coefficient and integral coefficient of the PI regulator respectively, is the integral operator;

[0029] Step 4: Obtain the results of the dq-axis self-inductance and mutual inductance of the dual three-phase synchronous reluctance motor varying with the dq-axis current through finite element simulation calculation;

[0030] Step 5: Tabulate the dq-axis self-inductance and mutual inductance results of the finite element simulation calculation, introduce the mutual inductance value, and update the dq-axis self-inductance and mutual inductance values in real time through the look-up table method to compensate for the position error caused by the magnetic saturation and cross-coupling effects, and the optimized hybrid effective magnetic flux linkage observer is obtained as follows:

[0031] ψ A_f = ψ αβ -(L q + jL dq )i αβ (11)

[0032] Another form of the optimized hybrid effective magnetic flux linkage observer is obtained by transforming formula (11) as follows:

[0033]

[0034] In the formula, ψ A_f is the optimized effective magnetic flux linkage, and Ldq is the dq-axis mutual inductance, ψ dq is the stator flux linkage in the rotor coordinate system, and j is the imaginary unit;

[0035] Step Six: Use the observation result of the optimized hybrid effective flux linkage observer as the input signal to the phase-locked loop. The rotor estimated electrical angle and the rotor estimated electrical angular velocity are the position information and speed information of the dual three-phase synchronous reluctance motor respectively.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adopts an optimized hybrid effective flux linkage observer to compensate for the non-linear change of inductance caused by magnetic saturation and cross-coupling effects, significantly improving the accuracy of the sensorless control algorithm. Compared with the traditional sensorless control method, it can effectively reduce the sensorless observation error caused by magnetic saturation and cross-coupling effects, expand the sensorless operating speed range of the dual three-phase synchronous reluctance motor, have good robustness, and meet the requirements of industrial production for high-performance sensorless control of dual three-phase synchronous reluctance motors. Brief Description of the Drawings

[0037] Figure 1 is the structural block diagram of the hybrid effective flux linkage observer in the control method of the present invention;

[0038] Figure 2 is the finite element simulation result of the dq-axis self-inductance and mutual inductance of the dual three-phase synchronous reluctance motor changing with the dq-axis current in the embodiment;

[0039] Figure 3 is the structural block diagram of the optimized hybrid effective flux linkage observer in the control method of the present invention;

[0040] Figure 4 is the experimental result of the sensorless control algorithm of the hybrid effective flux linkage observer before and after optimization when the load suddenly changes in the embodiment. Detailed Embodiments

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0042] As Figure 1 、 Figure 3 shown, a sensorless control method for a dual three-phase synchronous reluctance motor includes the following steps:

[0043] Step 1: Establish the mathematical model of a dual three-phase synchronous reluctance motor, perform vector space decoupling transformation on it, and obtain the voltage equation and flux linkage equation of the dual three-phase synchronous reluctance motor. Specifically:

[0044] The vector space decoupling transformation matrix used is expressed as follows:

[0045]

[0046] In the formula, θ e is the actual electrical angle of the rotor.

[0047] After the vector space decoupling transformation, the fundamental wave and the 12k±1 (k = 1, 2, 3…) harmonics are mapped into the d-q subplane, and the 6k±1 (k = 1, 3, 5…) harmonics are mapped into the z 1 -z 2 subplane, and the 6k±3 (k = 1, 3, 5…) harmonics are mapped into the o 1 -o 2 subplane.

[0048] Ignoring the cross-coupling effect, perform vector space decoupling transformation on the voltage equation and flux linkage equation of the dual three-phase synchronous reluctance motor respectively, and express them as follows:

[0049]

[0050] In the formula, u d , u q , u z1 , u z2 are the voltages of the corresponding subplanes respectively, i d , i q , i z1 , i z2 are the currents of the corresponding subplanes respectively, ψ d , ψ q , ψ z1 , ψ z2 are the flux linkages of the corresponding subplanes respectively, L d and L q are the direct-axis inductance and quadrature-axis inductance respectively, L aa1 is the leakage inductance, R is the stator resistance, and ω e is the actual electrical angular velocity of the rotor.

[0051] Step 2: Derive the voltage model and current model of the flux observer from the stator voltage equation of the dual three-phase synchronous reluctance motor. Specifically:

[0052] The stator voltage equation of the dual three-phase synchronous reluctance motor is expressed as follows:

[0053]

[0054] Where, u αβ is the stator voltage, i αβ is the stator current, and ψ αβ is the stator flux linkage in the stator coordinate system.

[0055] Furthermore, the stator flux linkage can be expressed as follows:

[0056]

[0057] Substituting Equation (3) into Equation (5), another expression for the stator flux linkage is obtained as follows:

[0058] ψ αβ = ((L d - L q )i d )·(cosθ e , sinθ e ) T + L q i αβ (6)

[0059] To accurately observe the stator flux linkage, the concept of effective flux linkage is introduced, and the relationship between the effective flux linkage and the stator flux linkage is expressed as follows:

[0060] ψ A = ψ αβ - L q i αβ (7)

[0061] Where, ψ A is the effective flux linkage.

[0062] Thus, the current model and voltage model of the effective flux linkage can be obtained as follows:

[0063]

[0064] Where, is the current model of the effective flux linkage, is the estimated electrical angle of the rotor, is the voltage model of the effective flux linkage, and u comp is the compensation value for the disturbance encountered during the flux linkage observation process.

[0065] Step 3: Combine the current model and voltage model of the effective flux linkage to obtain a hybrid effective flux linkage observer. Specifically:

[0066] The structural block diagram of the hybrid effective flux linkage observer is combined with Figure 1 shown. Among them, the calculation result of the current model is used as the input, the calculation result of the voltage model is used as the feedback, and the difference between the two is adjusted to zero through a PI regulator. The hybrid effective flux linkage observer is expressed as follows:

[0067]

[0068] Wherein, k p and k i are respectively the proportional coefficient and integral coefficient of the PI regulator, is the integral operator.

[0069] Step Four: Obtain the results of the self-inductance and mutual inductance of the dq axes of the dual three-phase synchronous reluctance motor varying with the dq axis currents through finite element simulation calculation.

[0070] Step Five: Tabulate the self-inductance and mutual inductance results of the dq axes obtained from the finite element simulation calculation, optimize the hybrid effective flux observer, and the structural block diagram of the optimized hybrid effective flux observer is combined with Figure 3 as shown, introduce the mutual inductance value and update the self-inductance and mutual inductance values of the dq axes in real time through the look-up table method to achieve the purpose of compensating for the position error caused by the magnetic saturation and cross-coupling effects. The optimized hybrid effective flux observer is expressed as follows:

[0071] ψ A_f = ψ αβ -(L q + jL dq )i αβ (11)

[0072] Performing transformation on formula (11) can obtain another form of the optimized hybrid effective flux observer as follows:

[0073]

[0074] Wherein, ψ A_f is the optimized effective flux, L dq is the mutual inductance of the dq axes, ψ dq is the stator flux linkage in the rotor coordinate system, and j is the imaginary unit.

[0075] Step Six: Take the observation result of the optimized hybrid effective flux observer as the input signal and send it to the phase-locked loop. The rotor estimated electrical angle and the rotor estimated electrical angular velocity are the position information and speed information of the dual three-phase synchronous reluctance motor.

[0076] Embodiment

[0077] This embodiment is based on the dual three-phase synchronous reluctance motor drive control platform. In the experiment, the motor speed is 200 r / min.

[0078] The finite element simulation results of the self-inductance and mutual inductance of the dq axes of the motor varying with the dq axis currents in the experiment are combined with Figure 2As shown, where part a) shows the finite element simulation results of the d-axis self-inductance varying with dq-axis currents; part b) shows the finite element simulation results of the q-axis self-inductance varying with dq-axis currents; part c) shows the finite element simulation results of the dq-axis mutual inductance varying with dq-axis currents.

[0079] In the experiment, the actual speed, phase A current, position error, and speed error of the motor are combined Figure 4 As shown, where part a) shows the experimental results of the sensorless control algorithm of the hybrid effective flux observer before optimization when the load suddenly changes; part a) shows the experimental results of the sensorless control algorithm of the optimized hybrid effective flux observer of the present invention when the load suddenly changes.

[0080] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0081] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A position sensorless control method for a dual three-phase synchronous reluctance motor, characterized in that: The following steps are involved: Step 1: Establish a mathematical model of a dual three-phase synchronous reluctance motor and perform a vector space decoupling transformation on it. The vector space decoupling transformation matrix used is expressed as follows: In the formula, θ e is the actual electrical angle of the rotor; The voltage equation and flux equation of the dual three-phase synchronous reluctance motor are transformed into vector space decoupling, which is expressed as follows: In the formula, u d 、u q 、u z1 、u z2 are the voltages of the corresponding sub-planes, i d 、i q 、i z1 、i z2 are the currents of the corresponding sub-planes, ψ d , q , z1 , z2 are the magnetic flux of the corresponding sub-plane, L d and L q are the direct-axis inductance and quadrature-axis inductance, L aa1 is leakage inductance, R is stator resistance, ω e is the actual electrical angular velocity of the rotor; Step 2: The stator voltage equation of the dual three-phase synchronous reluctance motor is expressed as follows: In the formula, u αβ is the stator voltage, i αβ is the stator current, ψ αβ is the stator flux in the stator coordinate system; Then the stator flux is expressed as follows: Substituting formula (3) into formula (5), another expression of the stator flux is as follows: ψ αβ =((L d -L q )i d )·(cosθ e ,sinθ e ) T +L q I αβ (6) Introducing effective flux, the relationship between effective flux and stator flux is expressed as follows: ψ A =ψ αβ -L q I αβ (7) In the formula, ψ A is the effective magnetic link; The current model and voltage model of the effective flux are expressed as follows: In the formula, is the current model of the effective flux linkage, Estimate the electrical angle for the rotor, is the voltage model of effective flux linkage, u comp is the compensation value for the disturbance encountered during the flux observation process; Step 3: Combine the current model and voltage model of the effective flux linkage. The calculation result of the current model is used as input, and the calculation result of the voltage model is used as feedback. The difference between the two is adjusted to zero through the PI regulator. The hybrid effective flux linkage observer is expressed as follows: In the formula, k p and k i are the proportional coefficient and integral coefficient of the PI regulator respectively, is the integral operator; Step 4: Obtain the results of the change of the dq axis self-inductance and mutual inductance of the dual three-phase synchronous reluctance motor with the dq axis current through finite element simulation calculation; Step 5: Tabulate the dq axis self-inductance and mutual inductance results calculated by finite element simulation, introduce the mutual inductance value and update the dq axis self-inductance and mutual inductance values ​​in real time through the table lookup method, compensate for the position error caused by magnetic saturation and cross-coupling effects, and obtain the optimized hybrid effective flux observer as follows: ψ A_f =ψ αβ -(L q +jL dq )i αβ (11) Another form of the optimized hybrid effective flux observer obtained by transforming formula (11) is as follows: In the formula, ψ A_f is the effective magnetic flux after optimization, L dq is the dq axis mutual inductance, ψ dq is the stator flux in the rotor coordinate system, j is an imaginary unit; Step 6: Send the observation results of the optimized hybrid effective flux observer as the input signal to the phase-locked loop, and the phase-locked loop outputs the estimated rotor electrical angle and the estimated electrical angular velocity of the rotor That is the position information and speed information of the dual three-phase synchronous reluctance motor.

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