Hysteresis prediction speed error elimination control method for permanent magnet synchronous motor system
By predicting and compensating model parameter errors in the permanent magnet synchronous motor system, the control accuracy and robustness problems caused by parameter changes in hysteresis ring prediction control are solved, and higher control accuracy, robustness and steady-state performance are achieved.
Patent Information
- Application Number
- CN202510328248.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-08-05
AI Technical Summary
The hysteresis ring prediction control method of existing permanent magnet synchronous motor systems relies on precise motor parameters, and parameter changes lead to dynamic performance degradation and steady-state error, affecting control accuracy and robustness.
By establishing a hysteresis prediction model for permanent magnet synchronous motor system, the model parameter error is predicted and compensation is performed, and voltage prediction is performed with the current reference value, the model error is eliminated, and the model accuracy and robustness are improved.
The control accuracy and robustness of the permanent magnet synchronous motor system are improved, the calculation amount and convergence speed problems are reduced, and the steady-state performance is achieved.
Smart Images
Figure CN120433651A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of permanent magnet synchronous motor systems, and in particular to a control method for eliminating hysteresis prediction speed errors of permanent magnet synchronous motor systems. Background Art
[0002] Permanent magnet synchronous motors (PMSMs) boast a simple structural design and compact size, high power density, a large power factor, and a wide speed regulation range. These significant advantages have led to their widespread application in numerous industrial sectors, including wind power generation, aerospace, and new energy vehicles. Therefore, improving the dynamic performance and motion control accuracy of PMSM drive systems is crucial. Model predictive control (MPC), with its advantages of intuitive modeling, simple control structure, and fast dynamic response, is increasingly being used in the control of PMSs. MPC is a special type of control in which the current control action is determined at each sampling instant by solving a finite-time open-loop optimal control problem. Compared to MPC, deadbeat predictive control (DBPC) directly uses the current setpoint and actual value to predict the required voltage based on the motor's discrete model, allowing the actual current value to deadbeat-track the setpoint at the next instant. By eliminating the need to solve an optimization problem at each control cycle, DBPC effectively reduces computational burden.
[0003] However, as a form of model prediction, hysteresis predictive control suffers from over-reliance on the model. To ensure motor control accuracy, hysteresis predictive control requires a precise control model, including the motor's electrical parameters and load information. However, due to temperature increases caused by continuous motor operation and external disturbances, motor parameters such as stator resistance, stator inductance, and permanent magnet flux can change, causing parameter mismatch, which in turn reduces motor dynamic performance, increases steady-state error, and even causes motor system instability.
[0004] Therefore, it is necessary to develop and design a control method for permanent magnet synchronous motor systems to solve the problem that the control performance is affected by the accuracy of model parameters in practice, and to overcome the shortcomings of conventional model predictive control such as large amount of calculation and slow convergence speed, so as to improve the control accuracy and robustness of permanent magnet synchronous motor drive systems. Summary of the Invention
[0005] The purpose of the present invention is to provide a control method for eliminating the hysteresis prediction speed error of a permanent magnet synchronous motor system, so as to solve the problem that the control performance is affected by the accuracy of model parameters in practice, overcome the shortcomings of conventional model predictive control such as large amount of calculation and slow convergence speed, and improve the control accuracy and robustness of the permanent magnet synchronous motor drive system.
[0006] The technical solution adopted to achieve the purpose of the present invention is:
[0007] A control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system comprises the following steps:
[0008] Step 1: Establish a mathematical model of the permanent magnet synchronous motor, use the hysteresis loop prediction model of the permanent magnet synchronous motor system to predict the current and speed in the d and q axis coordinate systems, and obtain the predicted values of the d and q axis currents at time k. And the predicted mechanical angular velocity ω e (k), and then respectively with the sampling value i of the d and q axis current at time k d (k), i q (k) and the sampling value of the mechanical angular velocity ω(k) are subtracted to obtain the model prediction error at the current moment. The model prediction error at the current moment includes the d-axis current error E d (k), q-axis current error E q (k) and speed error E ω (k);
[0009] Step 2: Based on the model prediction at the current moment obtained in step 1, combined with the hysteresis prediction model of the permanent magnet synchronous motor system, predict the parameter error, which includes the inductance error ΔL s , flux linkage error △ψ f and moment of inertia error △J;
[0010] Step 3: Based on the parameter error obtained in step 2, predict the prediction error of the hysteresis prediction model of the permanent magnet synchronous motor system at the next moment. The prediction error at the next moment includes the d-axis current error E at the next moment. d (k+1), the q-axis current error E at the next moment q (k+1) and the speed error E at the next moment ω (k+1);
[0011] Step 4: Add the parameter error obtained in step 2 and the prediction error at the next moment obtained in step 3 to the hysteresis prediction model of the permanent magnet synchronous motor system to compensate the predicted value, and combine the current reference value i under the d-axis and q-axis coordinates. dref 、i qref , and finally get the reference voltage u under d and q coordinates dref and u qref .
[0012] In the above technical solution, the hysteresis prediction model of the permanent magnet synchronous motor system in step 1 is:
[0013]
[0014] Where: Rs0 、L s0 , ψ f0 , J0 are the resistance, inductance, flux linkage and moment of inertia in the hysteresis prediction model of the permanent magnet synchronous motor system, B is the viscous friction coefficient, T L is the load torque, T s is the control period; i d (k-1), i q (k-1) are the sampling values of the d-axis and q-axis currents at the time k-1, ω(k-1) is the sampling value of the mechanical angular velocity at the time k-1, ω e (k-1) is the sampling value of the electrical angular velocity at time k-1, and ω e (k-1)=pω(k-1), p is the number of pole pairs, u d (k-1),u q (k-1) are the d-axis and q-axis components of the stator voltage at time k-1, ω e (k) is the predicted mechanical angular velocity at time k, are the predicted values of d-axis and q-axis currents at time k, is the predicted value of the q-axis current at time k-1.
[0015] In the above technical solution, in step 1,
[0016]
[0017] E ω (k)=ω e (k)-ω(k)
[0018] i d (k), i q (k) are the sampling values of the d-axis and q-axis currents at time k, and ω(k) is the sampling value of the mechanical angular velocity at time k.
[0019] In the above technical solution, in step 2,
[0020]
[0021] Where: △L s , △ψ f , △J is the inductance error, magnetic flux error and moment of inertia error, i d (k-2), i q (k-2) are the sampling values of the d-axis and q-axis currents at the k-2 moment, ω e (k-2) is the sampling value of the electrical angular velocity at time k-2, u q (k-2) is the q-axis component of the stator voltage at time k-2.
[0022] In the above technical solution, in step 3:
[0023]
[0024] In the above technical solution, in step 4:
[0025]
[0026] Where: i dref is the current reference value under the d-axis coordinate, i qref is the current reference value under the q-axis coordinate;
[0027]
[0028] i d (k+1), i q (k+1) are the sampling values of the d-axis and q-axis currents at the time k+1, ω(k+1) is the sampling value of the mechanical angular velocity at the time k+1, ω e (k+1) is the predicted mechanical angular velocity at time k+1, They are the predicted values of d-axis and q-axis currents at time k+1 respectively.
[0029] In the above technical solution, in step 4:
[0030] i dref =0
[0031]
[0032] Where: ref is the target speed, and ω(k+2) is the sampling value of the mechanical angular velocity at time k+2.
[0033] Compared with the prior art, the present invention has the following beneficial effects:
[0034] 1. The present invention proposes a control method for eliminating the hysteresis prediction speed error of a permanent magnet synchronous motor system, which solves the problem that the control performance is affected by the accuracy of model parameters in practice.
[0035] 2. The present invention calculates the parameter error by the deviation between the predicted value and the sampled value, and predicts the model prediction error at the next moment, thereby increasing the accuracy of the model and improving the robustness of the system.
[0036] 3. The present invention adopts the prediction error compensation method to eliminate the model error, and predicts the voltage required by the motor discrete model through the current set value and actual value, so that the actual current value at the next moment can track the set value without beat, with less calculation pressure and better steady-state performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 This is a structural block diagram of a hysteresis-predictive direct speed control method for a permanent magnet synchronous motor system based on prediction error elimination according to the present invention;
[0038] Figure 2 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION
[0039] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0040] Example 1
[0041] like Figure 1-Figure 2 As shown, a control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system includes the following steps:
[0042] Step 1: Establish a mathematical model of the permanent magnet synchronous motor, use the hysteresis loop prediction model of the permanent magnet synchronous motor system to predict the current and speed in the d and q axis coordinate systems, and obtain the predicted values of the d and q axis currents at time k. And the predicted mechanical angular velocity ω e (k), and then respectively with the sampling value i of the d and q axis current at time k d (k), i q (k) and the sampling value of the mechanical angular velocity ω(k) are subtracted to obtain the model prediction error at the current moment. The model prediction error at the current moment includes the d-axis current error E d (k), q-axis current error E q (k) and speed error E ω (k);
[0043] Step 2: According to the d-axis current error E obtained in step 1 d (k), q-axis current error E q (k) and speed error E ω (k) Combined with the hysteresis prediction model of the permanent magnet synchronous motor system, the parameter error is predicted, and the parameter error includes the inductance error ΔL s , flux error △ψ f and moment of inertia error △J;
[0044] Step 3: Based on the parameter error obtained in step 2, predict the prediction error of the hysteresis prediction model of the permanent magnet synchronous motor system at the next moment. The prediction error at the next moment includes the d-axis current error E at the next moment. d (k+1), the q-axis current error E at the next moment q (k+1) and the speed error E at the next moment ω (k+1);
[0045] Step 4: Add the parameter error obtained in step 2 and the prediction error at the next moment obtained in step 3 to the hysteresis prediction model of the permanent magnet synchronous motor system to compensate the predicted value, and combine the current reference value i under the d-axis and q-axis coordinates. dref 、i qref , and finally get the reference voltage u under d and q coordinates dref and u qref .
[0046] The present invention can ultimately solve the problem that control performance is affected by the accuracy of model parameters in practice, overcome the shortcomings of conventional model predictive control such as large amount of calculation and slow convergence speed, and improve the control accuracy and robustness of the permanent magnet synchronous motor drive system.
[0047] Example 2
[0048] like Figure 1-Figure 2 As shown, a control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system includes the following steps:
[0049] Step S1: Establish a hysteresis prediction model for the permanent magnet synchronous motor system based on the permanent magnet synchronous motor mathematical model, and calculate the predicted current in the d and q axis coordinate systems based on the hysteresis prediction model for the permanent magnet synchronous motor system. And the predicted mechanical angular velocity ω e (k), and then respectively compared with the sampling value i of the current in the d and q axis coordinate systems d (k), i q (k) and the sampling value of the mechanical angular velocity are subtracted to obtain the d-axis current error E d (k), q-axis current error E q (k) and speed error E ω (k).
[0050] The mathematical model of the permanent magnet synchronous motor includes the motion equation and voltage equation of the permanent magnet synchronous motor, as shown in equations (1) and (2):
[0051]
[0052] In formula (1), J is the motor moment of inertia, ω is the mechanical angular velocity, and t is the time; K t is the torque coefficient of the permanent magnet synchronous motor, and K t =1.5pψ f ψ f is the permanent magnet flux; p is the number of pole pairs; T L is the load torque; B is the viscous friction coefficient; i q is the q-axis component of the stator current.
[0053] In formula (2), x is the state variable, t is the time, x=[id i q ] T ,i q is the q-axis component of the stator current, i d is the d-axis component of the stator current; u is the control variable, u=[u d u q ] T ,u d 、u q are the d-axis and q-axis components of the stator voltage respectively; f(x,u)=[A1A2] T ; A1=1 / L s ·u d -1 / L s ·R s i d +pωi q ; A2=1 / L s ·u q -1 / L s ·R s i q -pωi d -1 / L s ψ f pω. L s is the stator inductance, R s is the stator resistance.
[0054] Establish a hysteresis prediction model for permanent magnet synchronous motor systems:
[0055] After discretizing equation (1), we can get
[0056]
[0057] Where, T s is the control period, ω(k) is the sampling value of the mechanical angular velocity at time k, ω(k-1) is the sampling value of the mechanical angular velocity at time k-1, i q (k-1) are the sampling values of the q-axis current at time -1.
[0058] After discretizing formula (2), we can get
[0059]
[0060] Where i d (k), i q (k) are the sampling values of the d-axis and q-axis currents at time k, i d (k-1), i q (k-1) are the sampling values of the d-axis and q-axis currents at the k-1 moment, u d (k-1),u q(k-1) are the d-axis and q-axis components of the stator voltage at time k-1, ω e (k-1) is the sampling value of the electrical angular velocity at time k-1, and ω e (k-1)=pω(k-1), where p is the number of pole pairs.
[0061] Let R s0 、L s0 , ψ f0 , J0 are the resistance, inductance, flux linkage and moment of inertia in the hysteresis loop prediction model of the permanent magnet synchronous motor system; R s 、L s , ψ f , J is the actual resistance, inductance, magnetic flux, and moment of inertia, and △R s , △L s , △ψ f , △J is the resistance error, inductance error, magnetic flux error and moment of inertia error, and the relationship between the three is:
[0062]
[0063] When the above parameters do not match, the hysteresis prediction model of the permanent magnet synchronous motor system will be updated to
[0064]
[0065] Where, are the predicted values of d-axis and q-axis currents at time k, ω e (k) is the predicted value of the mechanical angular velocity at time k, and the superscript e indicates that the model prediction value at this time contains an error; i d (k-1), i q (k-1) are the sampling values of the d-axis and q-axis currents at the time k-1, ω(k-1) is the sampling value of the mechanical angular velocity at the time k-1, and u d (k-1),u q (k-1) are the d-axis and q-axis components of the stator voltage at time k-1, is the predicted value of the q-axis current at time k-1.
[0066] According to the hysteresis prediction model of permanent magnet synchronous motor system, we can get ω e (k), sampling can obtain the sampling value i of the d and q axis current at time k d (k), i q The model prediction error is obtained by subtracting the sampling value ω(k) of the mechanical angular velocity at time k from the sampling value ω(k).
[0067]
[0068] At the same time, the hysteresis prediction model of the permanent magnet synchronous motor system can be obtained. When the system parameters change, the model prediction error (including the error E of the d and q axis currents) can be obtained through the hysteresis prediction model of the permanent magnet synchronous motor system. d (k), E q (k) and the error of mechanical angular velocity E ω (k)) and parameter error (inductance error △L s , flux error △ψ f The relationship between the moment of inertia error △J) is:
[0069]
[0070] Where: i d (k-2), i q (k-2) are the sampling values of the d-axis and q-axis currents at the k-2 moment, ω e (k-2) is the sampling value of the electrical angular velocity at time k-2, u q (k-2) is the q-axis component of the stator voltage at time k-2.
[0071] For the convenience of analysis, error analysis is performed on a single parameter:
[0072] (1) When the inductance is mismatched, assuming R s , ψ f , J do not change, that is, △ψ f , △R s , △J are both 0, there is
[0073]
[0074] (2) When the magnetic flux does not match, assuming R s 、L s , J do not change, that is, △L s , △R s , △J are both 0, there is
[0075]
[0076] (3) When the resistance is not matched, assuming L s , ψ f , J do not change, that is, △ψ f , △L s , △J are both 0, there is
[0077]
[0078] (4) When the moment of inertia does not match, assuming L s , ψ f 、R s Do not change, that is, △ψ f , △Ls , △R s are all 0,
[0079]
[0080] Step S2: Based on the model prediction error (d-axis current error E d (k), q-axis current error E q (k) and speed error E ω (k)), calculate the parameter error: inductance error △L s , flux error △ψ f and the moment of inertia error △J (the resistance change is small, so the error is negligible here).
[0081] The d-axis current error E d (k), q-axis current error E q (k) and speed error E ω (k) and inductance error △L s , flux error △ψ f The relationship between the moment of inertia error △J and the rotational inertia error △J is as follows:
[0082]
[0083] Step S3, according to the inductance error ΔL s , flux error △ψ f The prediction error E of the hysteresis prediction model of the permanent magnet synchronous motor system will be predicted by the rotational inertia error △J at the next moment d (k+1), E q (k+1) and E ω (k+1).
[0084]
[0085] Step S4: Add parameter error ΔL to the hysteresis prediction model of the permanent magnet synchronous motor system s , △ψ f and △J and model prediction error E d (k+1), E q (k+1) and E ω (k+1) is used for compensation, and the reference voltage u under the d-axis and q-axis coordinates is obtained according to the hysteresis predictive control principle. dref and u qref .
[0086] First, add the parameter error △L s , △ψ f and △J to compensate the hysteresis prediction model of the permanent magnet synchronous motor system in formula (3)-(4) (the resistance change is small, so the error is ignored here, that is, R s =Rs0 ):
[0087]
[0088] Then add the model prediction error E d (k+1), E q (k+1) and E ω (k+1) compensates the predicted amount:
[0089]
[0090] i d (k+1), i q (k+1) are the sampling values of the d-axis and q-axis currents at the time k+1, ω(k+1) is the sampling value of the mechanical angular velocity at the time k+1, ω e (k+1) is the predicted mechanical angular velocity at time k+1, They are the predicted values of d-axis and q-axis currents at time k+1 respectively.
[0091] Then, according to the hysteresis prediction model of the permanent magnet synchronous motor system of formula (3) and formula (4), the current reference values under the d-axis and q-axis coordinates are obtained (the reference value of the d-axis current is calculated according to i d =0 setting):
[0092]
[0093] Where i dref is the current reference value under the d-axis coordinate, i qref is the current reference value under the q-axis coordinate, ω ref is the target speed.
[0094] Finally, the reference voltages under the d-axis and q-axis coordinates are obtained according to the hysteresis predictive control principle:
[0095]
[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A control method for eliminating hysteresis prediction speed error in a permanent magnet synchronous motor system, characterized in that: The following steps are involved: Step 1: Establish a mathematical model of the permanent magnet synchronous motor and use the hysteresis loop prediction model of the permanent magnet synchronous motor system to predict the current and speed in the d and q axis coordinate systems to obtain the predicted values of the d and q axis currents at time k. And the predicted mechanical angular velocity ω e (k), and then respectively with the sampling value i of the d and q axis current at time k d (k), i q (k) and the sampling value of the mechanical angular velocity ω(k) are subtracted to obtain the model prediction error at the current moment. The model prediction error at the current moment includes the d-axis current error E d (k), q-axis current error E q (k) and the speed error E ω (k); Step 2: Based on the model prediction at the current moment obtained in step 1, combined with the hysteresis prediction model of the permanent magnet synchronous motor system, predict the parameter error, which includes the inductance error ΔL s , flux error △ψ f and moment of inertia error △J; Step 3: Based on the parameter error obtained in step 2, the prediction error of the hysteresis prediction model of the permanent magnet synchronous motor system at the next moment is predicted. The prediction error at the next moment includes the d-axis current error E at the next moment. d (k+1), the q-axis current error E at the next moment q (k+1) and the speed error E at the next moment ω (k+1); Step 4: Add the parameter error obtained in step 2 and the prediction error at the next moment obtained in step 3 to the hysteresis prediction model of the permanent magnet synchronous motor system to compensate the predicted value, and combine the current reference value i under the d-axis and q-axis coordinates. dref 、i qref , and finally get the reference voltage u under d and q coordinates dref and u qref .
2. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 1, characterized in that: The hysteresis prediction model of the permanent magnet synchronous motor system in step 1 is: Where: R s0 , L s0 , ψ f0 , J0 are the resistance, inductance, flux linkage and moment of inertia in the hysteresis prediction model of the permanent magnet synchronous motor system, B is the viscous friction coefficient, T L is the load torque, T s is the control period; i d (k-1), i q (k-1) are the sampling values of the d-axis and q-axis currents at the time k-1, ω(k-1) is the sampling value of the mechanical angular velocity at the time k-1, ω e (k-1) is the sampling value of the electrical angular velocity at time k-1, and ω e (k-1)=pω(k-1), p is the number of pole pairs, u d (k-1),u q (k-1) are the d-axis and q-axis components of the stator voltage at time k-1, ω e (k) is the predicted mechanical angular velocity at time k, are the predicted values of d-axis and q-axis currents at time k, is the predicted value of the q-axis current at time k-1.
3. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 1, characterized in that: In the step 1, E ω (k)=ω e (k)-ω(k) i d (k), i q (k) are the sampling values of the d-axis and q-axis currents at time k, and ω(k) is the sampling value of the mechanical angular velocity at time k.
4. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 1, characterized in that: In the step 2, Where: △L s , △ψ f , △J is the inductance error, magnetic flux error and moment of inertia error, i d (k-2), i q (k-2) are the sampling values of the d-axis and q-axis currents at the k-2 moment, ω e (k-2) is the sampling value of the electrical angular velocity at time k-2, u q (k-2) is the q-axis component of the stator voltage at time k-2.
5. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 1, characterized in that: In step 3:
6. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 1, characterized in that: In step 4: Where: i dref is the current reference value under the d-axis coordinate, i qref is the current reference value under the q-axis coordinate; i d (k+1), i q (k+1) are the sampling values of the d-axis and q-axis currents at the time k+1, ω(k+1) is the sampling value of the mechanical angular velocity at the time k+1, ω e (k+1) is the predicted mechanical angular velocity at time k+1, They are the predicted values of d-axis and q-axis currents at time k+1 respectively.
7. The control method for eliminating hysteresis prediction speed error of a permanent magnet synchronous motor system according to claim 6, characterized in that: In step 4: i dref ＝0 Where: ref is the target speed, and ω(k+2) is the sampling value of the mechanical angular velocity at time k+2.