Permanent magnet synchronous motor high-performance prediction control method based on sliding mode observer

Abstract

The invention discloses a permanent magnet synchronous motor high-performance prediction control method based on a sliding-mode observer, and the method comprises the steps: S1, collecting the position and mechanical angular velocity information of a rotor, collecting the three-phase voltage and current data of a permanent magnet synchronous motor, and converting the three-phase voltage and current data into the voltage and current of a motor stator under a two-phase rotating coordinate system; s2, constructing a speed ring sliding-mode observer, estimating electrical and mechanical parameter perturbation interference and load torque interference on line, designing a rotating speed ring deadbeat prediction controller, outputting reference current at the next moment, and setting the amplitude limit of the output reference current; s3, a current loop sliding mode observer is constructed, electrical parameter perturbation interference is estimated online, a current loop prediction controller is designed in combination with the dead-beat prediction control principle, and voltage at the next moment is output; and S4, carrying out amplitude limiting modulation on the output voltage, obtaining a voltage under a static coordinate system through Park inverse transformation according to the voltage after amplitude limiting modulation, and outputting a switching signal to a three-phase inverter by combining a two-level space vector modulation module to drive the permanent magnet synchronous motor to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer. Background Art

[0002] Permanent magnet synchronous motor has the advantages of simple structure, high integration, high transmission efficiency, etc. Since permanent magnet synchronous motor is a high-order nonlinear uncertain system, a fast and stable current loop is the key to ensure the torque performance of permanent magnet synchronous motor. Conventional feedback control is difficult to meet the needs of high-precision control in complex operation. Compared with traditional control methods, the permanent magnet synchronous motor control system based on model predictive control method has good dynamic performance and has received widespread attention in recent years. However, due to the inevitable existence of internal parameter perturbations, external load disturbances and other factors in the actual permanent magnet synchronous motor system, it is difficult to obtain the expected control performance of the motor output torque and speed under predictive control.

[0003] In order to improve the disturbance suppression capability and control accuracy of permanent magnet synchronous motors, some scholars have proposed methods such as electrical parameter identification, robust predictive control, and disturbance observer estimation and disturbance feedforward compensation.

[0004] The electrical parameter identification method can identify the actual parameters of the motor, thereby improving the control performance of the predictive control system. However, this method will increase the amount of calculation and system complexity, and has high requirements on the performance of the control system. In addition, the identification accuracy of the parameter identification method will be affected by external interference, resulting in a large difference between the identified parameters and the actual parameters. Therefore, when applying the parameter identification method, it is necessary to properly handle the external interference. The robust predictive control algorithm is to design a fixed predictive controller in the worst case. Compared with the traditional predictive control algorithm, it improves the stability margin, so that the system can still maintain good control performance under a wide range of external interference and parameter changes. However, since the PMSM system may be close to the nominal operating conditions in most cases, it may be too conservative and cannot obtain the required high control performance.

[0005] The present invention estimates the system disturbance by constructing a disturbance observer and performs feed-forward compensation on the disturbance estimate. In this way, the influence of the internal parameter perturbation of the system and the external disturbance on the performance of the predictive control system can be suppressed, the dependence of the predictive control on the parameters of the motor can be reduced, and the robustness of the permanent magnet synchronous motor predictive control system can be improved. Summary of the invention

[0006] In view of the technical problems existing in the prior art, the present invention provides a high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer, which has simple control, high tracking accuracy, good robust performance, and fast dynamic response speed.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0008] A high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer, characterized in that it comprises the following steps:

[0009] Step S1: Collect rotor position and mechanical angular velocity information, collect three-phase voltage and current data of the permanent magnet synchronous motor, and convert them into motor stator voltage and current in a two-phase rotating coordinate system;

[0010] Step S2: construct a speed loop sliding mode observer, estimate the electrical and mechanical parameter perturbation disturbance and load torque disturbance online, design a speed loop deadbeat prediction controller, output the reference current at the next moment, and set the limit of the output reference current;

[0011] Step S3: construct a current loop sliding mode observer, estimate the electrical parameter perturbation interference online, design a current loop predictive controller based on the deadbeat predictive control principle, and output the voltage at the next moment;

[0012] Step S4: performing amplitude limiting modulation on the output voltage, obtaining the voltage in the stationary coordinate system through Park inverse transformation according to the amplitude limiting modulated voltage, and outputting the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate in combination with the two-level space vector modulation module.

[0013] As a further improvement of the above technical solution:

[0014] Preferably, the step S1 specifically includes the following method:

[0015] The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer according to claim 1 is characterized in that, in step S1, the Clark and Park transformations of the natural coordinate system ABC to the rotating dq coordinate system are:

[0016]

[0017]

[0018] Among them, K A ,K B ,K C Represents the three-phase voltage / current of the permanent magnet synchronous motor. The three-phase voltage / current is collected through the voltage / current sensor. K α ,K β Represents the voltage / current of the permanent magnet synchronous motor in the stationary coordinate system, K d ,K q Represents the voltage / current of the permanent magnet synchronous motor in the two-phase rotating coordinate system.

[0019] Preferably, the above technical solution, in step S2, specifically includes the following method:

[0020] Step S21: Establish the mechanical motion equation of the permanent magnet synchronous motor:

[0021]

[0022] Among them, p n is the number of motor pole pairs i q represents the current of the permanent magnet synchronous motor in the q-axis direction, ω is the mechanical angular velocity, ψ f represents the permanent magnet flux, J is the moment of inertia, T L is the load torque;

[0023] The permanent magnet synchronous motor undergoes electrical and mechanical parameter perturbations during operation:

[0024]

[0025] Among them, ψ f0 , J0 is the nominal value, Δψ f , ΔJ is the perturbation of the permanent magnet flux and moment of inertia;

[0026] Taking the electrical and mechanical parameter perturbation and load torque as the total disturbance, the mechanical motion equation becomes:

[0027]

[0028] Among them, f ω Expressed as the total disturbance of the speed loop channel:

[0029]

[0030] Step S22: construct a speed loop sliding mode observer to estimate the total disturbance of the speed loop online;

[0031] A smooth and continuous sigmoid(s) function is used to replace the sign function:

[0032]

[0033] Where α is a constant, and the value of α determines the thickness of the boundary layer and the steepness of the sigmoid(s) function;

[0034] The speed loop sliding mode observer is designed as:

[0035]

[0036] In the formula is the estimated value of ω, b ω is the observer gain value;

[0037] Design sliding surface function s ω :

[0038]

[0039] Where e ω is the speed estimation error, the total disturbance of the speed loop estimation for:

[0040]

[0041] Select the sliding mode gain b ω So that:

[0042]

[0043] Step S23: Use the system model information to construct a speed loop deadbeat predictive controller:

[0044] The total disturbance of the speed loop observed by the sliding mode observer Introduce equation (5) and use the forward Euler difference method to establish the speed loop predictive control model;

[0045] The speed loop sampling period is T sl , forward Euler difference gives:

[0046]

[0047] Let ω(m+1)=ω * ,i q (m+1)=i q * , the expected current required by the speed loop is:

[0048]

[0049] Step S24: construct reference current limit:

[0050] In the control of permanent magnet synchronous motor, i q * Set the restrictions to:

[0051]

[0052] Among them, I max It is the maximum current amplitude set according to the actual motor situation.

[0053] Preferably, in the above technical solution, step S3 specifically includes the following method:

[0054] Step S31: Establishing the voltage equation of the surface-mounted permanent magnet synchronous motor magnetic field orientation dq coordinate system:

[0055]

[0056] Among them, u d 、u q 、i d 、i q They represent the voltage and current of the permanent magnet synchronous motor in the d-axis and q-axis directions respectively, L is the stator inductance, ω is the mechanical angular velocity, R, ω e is the stator resistance, electrical angular velocity, ψ f represents the permanent magnet flux;

[0057] Consider electrical parameter uncertainty:

[0058]

[0059] Among them, R0 and L0 are nominal values, ΔR and ΔL are the perturbations of stator resistance and stator inductance parameters;

[0060] Combining equations (4) and (16) and substituting them into equation (15), the voltage equation of the permanent magnet synchronous motor becomes:

[0061]

[0062] Among them, f d 、f q Represents the total disturbance of each channel, which are:

[0063]

[0064] Step S32: construct a current loop sliding mode observer to estimate the total disturbance of the current loop online:

[0065] The uncertainty of electrical parameter perturbation is estimated online by constructing a current loop sliding mode observer:

[0066]

[0067] In the formula for i d 、i q The estimated value of b d,q is the observer gain value;

[0068] Design sliding surface function s d,q :

[0069]

[0070] Where e d,q is the current estimation error. Substituting (20) into (19) we obtain:

[0071]

[0072] Among them, the total disturbance estimated by the dq axis is for:

[0073]

[0074] From (17) and (21), we get the error dynamic equation:

[0075]

[0076] Select the sliding mode gain b d , b q So that:

[0077]

[0078] Step S33: construct a deadbeat current loop predictive controller using model information:

[0079] The total disturbance of the dq axis observed by the sliding mode observer Introducing equation (17), forward Euler difference is obtained, where T s is the current loop sampling period, usually taken as the mechanical quantity sampling time T sl 1 / 10 of the original value, the discretized permanent magnet synchronous motor current prediction model is:

[0080]

[0081] in:

[0082]

[0083] According to equation (25), the stator voltage equation in the rotating dq coordinate system at time k is derived:

[0084]

[0085] In the formula, i(k+1) is i * (k) represents u(k+1), and u * (k) indicates that the input voltage u at time k is obtained. * The value of (k):

[0086]

[0087] Preferably, the above technical solution, in step S4, specifically includes the following method:

[0088] Step 41: Constructing the Voltage Limiting Modulation Module:

[0089] According to the inverter output voltage capability, when the voltage is greater than When , the voltage is limited and modulated:

[0090]

[0091] Step 42: Construct the Inverse Park Transform Module:

[0092] Construct the inverse Park transformation from the rotating dq coordinate system to the stationary coordinate system:

[0093]

[0094] in, is the output voltage in the two-phase rotating coordinate system, U α ,U β It is the voltage output in the stationary coordinate system. According to the output voltage, combined with the two-level space vector modulation module, it outputs the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate.

[0095] The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer provided by the present invention has the following advantages compared with the prior art:

[0096] (1) The high-performance predictive control method for permanent magnet synchronous motor based on sliding mode observer of the present invention takes permanent magnet synchronous motor as the research object, based on the idea of ​​disturbance estimation and active compensation, the control system has simple structure, excellent tracking performance and good dynamic performance. Under the condition that the speed and current can be measured, on the basis of the traditional current loop deadbeat predictive control, the present invention proposes a design method for permanent magnet synchronous motor predictive control system based on sliding mode observer, by designing a sliding mode disturbance observer to estimate the perturbation disturbance of the electrical parameters of the permanent magnet synchronous motor online, using the disturbance observation value, combined with the deadbeat predictive control principle to design the current loop predictive controller, effectively reducing the system parameter dependence and improving the robustness of the predictive control system.

[0097] (2) The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer of the present invention replaces the proportional-integral controller of the speed loop in the traditional current predictive control with a speed loop zero-beat predictive controller. Since the traditional current predictive control often uses a proportional-integral controller in the speed loop, the integral action of the proportional-integral controller accumulates the speed deviation to eliminate the tracking error. This results in the permanent magnet synchronous motor being unable to quickly obtain the current loop reference current given value when the load torque suddenly changes or the speed changes, resulting in poor dynamic response performance of the system. While ensuring that the control system has good dynamic response performance, the present invention designs a sliding mode disturbance observer to online estimate the mechanical parameter perturbations and load disturbances of the permanent magnet synchronous motor, and uses the disturbance observation value to design a speed loop predictive controller in combination with the zero-beat predictive control principle to achieve fast and high-precision tracking of the system output to the reference input. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 It is a schematic diagram of the process of the present invention.

[0099] Figure 2 It is a curve diagram showing the relationship between the sigmoid(s) function and the parameter α of the present invention.

[0100] Figure 3 It is a structural block diagram of the permanent magnet synchronous motor control system of the present invention.

[0101] Figure 4 The present invention is compared with the traditional deadbeat current prediction control method in the simulation verification of starting and speed change control under no-load conditions.

[0102] Figure 5 This is a simulation verification comparison of the load disturbance resistance capability of the method of the present invention and the traditional zero-beat current prediction control method.

[0103] Fig. 6A It is the waveform diagram of the d-axis reference current and actual current when the parameters of the traditional deadbeat current prediction control method are perturbed.

[0104] Figure 6B It is a waveform diagram of the d-axis reference current and the actual current when parameter perturbation occurs in the method of the present invention.

[0105] Fig. 7A It is the waveform diagram of q-axis reference current and actual current when parameter perturbation occurs in the traditional deadbeat current prediction control method.

[0106] Figure 7B It is a waveform diagram of q-axis reference current and actual current when parameter perturbation occurs in the method of the present invention.

[0107] Figure 8 This is a speed simulation verification comparison of the parameter disturbance resistance capability of the method of the present invention and the traditional zero-beat current prediction control method. DETAILED DESCRIPTION

[0108] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0109] like Figure 1 As shown, a high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer of the present invention comprises the following steps:

[0110] Step S1: Collect rotor position and mechanical angular velocity information, collect three-phase voltage and current data of the permanent magnet synchronous motor, and convert them into motor stator voltage and current in a two-phase rotating coordinate system;

[0111] Step S2: construct a speed loop sliding mode observer, estimate the electrical and mechanical parameter perturbation disturbance and load torque disturbance online, design a speed loop deadbeat prediction controller, output the reference current at the next moment, and set the limit of the output reference current;

[0112] Step S3: construct a current loop sliding mode observer, estimate the electrical parameter perturbation interference online, design a current loop predictive controller based on the deadbeat predictive control principle, and output the voltage at the next moment;

[0113] Step S4: performing amplitude limiting modulation on the output voltage, obtaining the voltage in the stationary coordinate system through Park inverse transformation according to the amplitude limiting modulated voltage, and outputting the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate in combination with the two-level space vector modulation module.

[0114] In the specific implementation, in step S1, the Clark and Park transformation of the natural coordinate system ABC to the rotation dq coordinate system is established:

[0115]

[0116]

[0117] Among them, K A ,K B ,K C Represents the three-phase voltage / current of the permanent magnet synchronous motor. The three-phase voltage / current is collected through the voltage / current sensor. K α ,K β Represents the voltage / current of the permanent magnet synchronous motor in the stationary coordinate system, K d ,K q Represents the voltage / current of the permanent magnet synchronous motor in the two-phase rotating coordinate system.

[0118] In the specific implementation, the step S2 specifically includes the following steps:

[0119] Step S21: Establish the mechanical motion equation of the permanent magnet synchronous motor:

[0120]

[0121] Among them, p n is the number of motor pole pairs i q represents the current of the permanent magnet synchronous motor in the q-axis direction, ω is the mechanical angular velocity, ψ f represents the permanent magnet flux, J is the moment of inertia, T L is the load torque;

[0122] The permanent magnet synchronous motor inevitably has electrical and mechanical parameter perturbations during operation:

[0123]

[0124] Among them, ψ f0 , J0 is the nominal value, Δψ f , ΔJ is the perturbation of the permanent magnet flux and moment of inertia;

[0125] Taking the electrical and mechanical parameter perturbation and load torque as the total disturbance, the mechanical motion equation becomes:

[0126]

[0127] Among them, f ω Expressed as the total disturbance of the speed loop channel:

[0128]

[0129] Step S22: construct a speed loop sliding mode observer to estimate the total disturbance of the speed loop online;

[0130] For specific application examples, see Figure 3 , which is a structural block diagram of a control system constructed according to the method of the present invention in a specific application example. Since the traditional sliding mode observer often uses a sign function as a switching function when constructing, and the switching characteristics of the sign function will make the sliding mode chattering phenomenon obvious, a smooth and continuous sigmoid (s) function is used to replace the sign function:

[0131]

[0132] Where α is a constant. The value of α determines the thickness of the boundary layer and the steepness of the sigmoid(s) function. The smaller α is, the smoother the sigmoid(s) function is. Figure 2 As shown in the figure, the more obvious the chattering suppression effect is, the slower the observer converges. The value of α is reasonably selected so that the observer can respond quickly and suppress chattering at the same time.

[0133] The speed loop sliding mode observer is designed as:

[0134]

[0135] In the formula is the estimated value of ω, b ω is the observer gain value;

[0136] Design sliding surface function s ω :

[0137]

[0138] Where e ω is the speed estimation error, the total disturbance of the speed loop estimation for:

[0139]

[0140] By choosing a suitable sliding mode gain b ω , ensuring that the sliding mode observer can achieve high-precision estimation of the total disturbance, that is:

[0141]

[0142] Step S23: Use the system model information to construct a speed loop deadbeat predictive controller:

[0143] The total disturbance of the speed loop observed by the sliding mode observer Introduce equation (5) and use the forward Euler difference method to establish the speed loop predictive control model;

[0144] The speed loop sampling period is T sl , forward Euler difference gives:

[0145]

[0146] Let ω(m+1)=ω * ,i q (m+1)=i q * , the expected current required by the speed loop is:

[0147]

[0148] Step S24: construct reference current limit:

[0149] In the control of permanent magnet synchronous motors, especially during the startup process, in order to protect the inverter and servo system from damage caused by excessive current, it is necessary to q * Set the restrictions to:

[0150]

[0151] Among them, I max It is the maximum current amplitude set according to the actual motor situation.

[0152] In the specific implementation, the step S3 specifically includes the following steps:

[0153] Step S31: Establishing the voltage equation of the surface-mounted permanent magnet synchronous motor magnetic field orientation dq coordinate system:

[0154]

[0155] Among them, u d 、u q 、id 、i q They represent the voltage and current of the permanent magnet synchronous motor in the d-axis and q-axis directions respectively, L is the stator inductance, ω is the mechanical angular velocity, R, ω e is the stator resistance, electrical angular velocity, ψ f represents the permanent magnet flux;

[0156] Consider electrical parameter uncertainty:

[0157]

[0158] Among them, R0 and L0 are nominal values, ΔR and ΔL are the perturbations of stator resistance and stator inductance parameters;

[0159] Combining equations (4) and (16) and substituting them into equation (15), the voltage equation of the permanent magnet synchronous motor becomes:

[0160]

[0161] Among them, f d 、f q Represents the total disturbance of each channel, which are:

[0162]

[0163] Step S32: construct a current loop sliding mode observer to estimate the total disturbance of the current loop online;

[0164] The uncertainty of electrical parameter perturbation is estimated online by constructing a current loop sliding mode observer:

[0165]

[0166] In the formula for i d 、i q The estimated value of b d,q is the observer gain value;

[0167] Design sliding surface function s d,q :

[0168]

[0169] Where e d,q is the current estimation error. Substituting (20) into (19) we obtain:

[0170]

[0171] Among them, the total disturbance estimated by the dq axis is for:

[0172]

[0173] From (17) and (21), we get the error dynamic equation:

[0174]

[0175] By choosing the sliding mode gain b d , b q To ensure that the sliding mode observer can achieve high-precision estimation of the total disturbance, we have:

[0176]

[0177] Step S33: construct a deadbeat current loop predictive controller using system model information:

[0178] The total disturbance of the dq axis observed by the sliding mode observer Introducing equation (17), forward Euler difference is obtained, where T s is the current loop sampling period, usually taken as the mechanical quantity sampling time T sl 1 / 10 of the original value, the discretized permanent magnet synchronous motor current prediction model is:

[0179]

[0180] in:

[0181]

[0182] According to equation (25), the stator voltage equation in the rotating dq coordinate system at time k is derived:

[0183]

[0184] In the formula, i(k+1) is i * (k) represents u(k+1), and u * (k) indicates that the input voltage u at time k is obtained. * The value of (k):

[0185]

[0186] In the specific implementation, the step S4 specifically includes the following steps:

[0187] Step 41: Constructing the Voltage Limiting Modulation Module:

[0188] Considering the inverter output voltage capability, the voltage amplitude needs to be limited. When , the voltage is limited and modulated:

[0189]

[0190] Step 42: Construct the Inverse Park Transform Module:

[0191] Construct the inverse Park transformation from the rotating dq coordinate system to the stationary coordinate system:

[0192]

[0193] in, is the output voltage in the two-phase rotating coordinate system, U α ,U β It is the voltage output in the stationary coordinate system. According to the output voltage, combined with the two-level space vector modulation module, it outputs the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate.

[0194] Experimental verification

[0195] The present invention is further described below using a permanent magnet synchronous motor control experiment.

[0196] In order to verify the feasibility and superiority of the method proposed in the present invention under different working conditions, this example uses MATLAB / SIMULINK simulation software to build a permanent magnet synchronous motor model, and performs simulation comparison with the conventional deadbeat current prediction control method. The specific motor parameters used in this example are listed in Table 1.

[0197] Table 1 Parameters of surface mounted permanent magnet motor

[0198]

[0199] Comparison and verification:

[0200] When the control method proposed in the present invention is used for comparative verification, the speed loop and the current loop adopt the high-performance predictive control method of the permanent magnet synchronous motor based on the sliding mode observer proposed in the present invention, with sampling periods of 0.002s and 0.0002s respectively, parameter α=4, and observer gains of b d =b q =80000, b ω =50000, the current limit is set to ±30A, and the voltage limit is set to

[0201] The method proposed in the present invention is compared with the traditional deadbeat current prediction control (DPCC). The parameters of the current prediction controller are consistent with those of the present invention. The parameters of the PI speed controller are set using the bandwidth design method proposed in the literature (reference: Singh B, Murshid SA grid-interactive permanent-magnet synchronous motor-driven solar water-pumping system [J]. IEEE Transactions on Industry Applications, 2018, 54 (5): 5549-5561.). The speed PI controller parameters are designed as the proportional coefficient k sp =50*J / (1.5P n ψ f0 ), integration coefficient k si =50*k sp .

[0202] (1) Simulation verification of starting and speed change control under no-load conditions.

[0203] The permanent magnet synchronous motor is started at a given speed of 500r / min without load, and the given speed changes to 1000r / min in 0.2s.

[0204] Figure 4 The simulation waveforms of the conventional DPCC method based on PI speed control and the high-performance predictive control method of permanent magnet synchronous motor based on sliding mode observer (SMO_DPSCC) in two situations of no-load starting and variable speed control are shown in Figure 2. Figure 4 It can be seen that the use of predictive controller in the speed loop can significantly improve the dynamic response speed of the control system and reduce the system overshoot, making the speed performance of SMO_DPSCC better than that of DPCC strategy.

[0205] (2) Simulation verification considering load mutation.

[0206] The permanent magnet synchronous motor is started at a given speed of 1200r / min without load. At 0.2s, the load torque of the servo system suddenly increases to 10N·m. Figure 5 The speed waveforms simulated by DPCC and the method of the present invention SMO_DPSCC show that the speed loop predictive controller designed by online estimating the total disturbance of the speed loop using the sliding mode disturbance observer has a shorter transition process time and a stronger ability to resist load disturbances compared with the DPCC method.

[0207] (3) Simulation verification considering parameter perturbation.

[0208] The permanent magnet synchronous motor was started at a given speed of 1200 r / min and a load of 10 N·m. Parameter perturbation occurred at 0.2 s, and both the electrical and mechanical parameters became half of the nominal values.

[0209] Fig. 6A , Figure 6B They are respectively the d-axis reference current and actual current waveforms of DPCC and the method SMO_DPSCC of the present invention when parameter perturbation occurs, Fig. 7A , Figure 7B The q-axis reference current and actual current waveforms of DPCC and the method SMO_DPSCC of the present invention under the condition of parameter perturbation are shown respectively. It can be seen that the current of DPCC has obvious oscillation under the condition of parameter perturbation, and the sliding mode observer constructed by the present invention can effectively observe parameter uncertainty and realize high-precision tracking of the reference current.

[0210] Figure 8 The speed simulation verification comparison of the parameter disturbance resistance capability of the method of the present invention and the traditional deadbeat current prediction control method shows that the method proposed in the present invention has a stronger parameter disturbance resistance capability, can quickly recover after parameter perturbation occurs, and can accurately track the reference speed.

[0211] The above implementation cases are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, they are not intended to limit the present invention. Therefore, any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-performance predictive control method for permanent magnet synchronous motor based on sliding mode observer, It is characterized in that The following steps are involved: Step S1: Collect rotor position and mechanical angular velocity information, collect three-phase voltage and current data of the permanent magnet synchronous motor, and convert them into motor stator voltage and current in a two-phase rotating coordinate system; Step S2: construct a speed loop sliding mode observer, estimate the electrical and mechanical parameter perturbation disturbance and load torque disturbance online, design a speed loop deadbeat prediction controller, output the reference current at the next moment, and set the limit of the output reference current; Step S3: construct a current loop sliding mode observer, estimate the electrical parameter perturbation interference online, design a current loop predictive controller based on the deadbeat predictive control principle, and output the voltage at the next moment; Step S4: performing amplitude limiting modulation on the output voltage, obtaining the voltage in the stationary coordinate system through Park inverse transformation according to the amplitude limiting modulated voltage, and outputting the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate in combination with the two-level space vector modulation module.

2. The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer according to claim 1, It is characterized in that In step S1, the Clark and Park transformation of the natural coordinate system ABC to the rotating dq coordinate system is: Among them, K A ,K B ,K C Represents the three-phase voltage / current of the permanent magnet synchronous motor. The three-phase voltage / current is collected through the voltage / current sensor. K α ,K β Represents the voltage / current of the permanent magnet synchronous motor in the stationary coordinate system, K d ,K q Represents the voltage / current of the permanent magnet synchronous motor in the two-phase rotating coordinate system.

3. The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer according to claim 2, It is characterized in that The step S2 specifically includes the following method: Step S21: Establish the mechanical motion equation of the permanent magnet synchronous motor: Among them, p n is the number of pole pairs of the motor, i q represents the current of the permanent magnet synchronous motor in the q-axis direction, ω is the mechanical angular velocity, ψ f represents the permanent magnet flux, J is the moment of inertia, T L is the load torque; The permanent magnet synchronous motor undergoes electrical and mechanical parameter perturbations during operation: Among them, ψ f0 , J 0 is the nominal value, Δψ f , ΔJ is the perturbation of the permanent magnet flux and moment of inertia; Taking the electrical and mechanical parameter perturbation and load torque as the total disturbance, the mechanical motion equation becomes: Among them, f ω Expressed as the total disturbance of the speed loop channel: Step S22: construct a speed loop sliding mode observer to estimate the total disturbance of the speed loop online; A smooth and continuous sigmoid(s) function is used to replace the sign function: Where α is a constant, and the value of α determines the thickness of the boundary layer and the steepness of the sigmoid(s) function; The speed loop sliding mode observer is designed as: In the formula, is the estimated value of ω, b ω is the observer gain value; Design sliding surface function s ω : Where e ω is the speed estimation error, the total disturbance of the speed loop estimation for: Select the sliding mode gain b ω So that: Step S23: Use the system model information to construct a speed loop deadbeat predictive controller: The total disturbance of the speed loop observed by the sliding mode observer Introduce equation (5) and use the forward Euler difference method to establish the speed loop predictive control model; The speed loop sampling period is T sl , forward Euler difference gives: Let ω(m+1)=ω * , The expected current required for the speed loop is: Step S24: construct reference current limit: In the control of permanent magnet synchronous motor, i q * Set the restrictions to: Among them, I max It is the maximum current amplitude set according to the actual motor situation.

4. The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer according to claim 3, It is characterized in that The step S3 specifically includes the following method: Step S31: Establishing the voltage equation of the surface-mounted permanent magnet synchronous motor magnetic field orientation dq coordinate system: Among them, u d 、u q 、i d 、i q They represent the voltage and current of the permanent magnet synchronous motor in the d-axis and q-axis directions respectively, L is the stator inductance, ω is the mechanical angular velocity, R, ω e is the stator resistance, electrical angular velocity, ψ f represents the permanent magnet flux; Consider electrical parameter uncertainty: Among them, R 0 , L 0 is the nominal value, ΔR and ΔL are the perturbations of stator resistance and stator inductance parameters; Combining equations (4) and (16) and substituting them into equation (15), the voltage equation of the permanent magnet synchronous motor becomes: Among them, f d 、f q Represents the total disturbance of each channel, which are: Step S32: construct a current loop sliding mode observer to estimate the total disturbance of the current loop online: estimate the uncertainty of electrical parameter perturbation online by constructing a current loop sliding mode observer: In the formula, for i d 、i q The estimated value of b d,q is the observer gain value; Design sliding surface function s d,q : Where e d,q is the current estimation error. Substituting (20) into (19) we obtain: Among them, the total disturbance estimated by the dq axis is for: The error dynamic equation is obtained from equations (17) and (21): Select the sliding mode gain b d , b q So that: Step S33: construct a deadbeat current loop predictive controller using model information: The total disturbance of the dq axis observed by the sliding mode observer Introducing equation (17), forward Euler difference is obtained, where T s is the current loop sampling period, usually taken as the mechanical quantity sampling time T sl 1 / 10 of the original value, the discretized permanent magnet synchronous motor current prediction model is: in: According to equation (25), the stator voltage equation in the rotating dq coordinate system at time k is derived: In the formula, i(k+1) is i * (k) represents u(k+1), and u * (k) indicates that the input voltage u at time k is obtained. * The value of (k):

5. The high-performance predictive control method for a permanent magnet synchronous motor based on a sliding mode observer according to claim 4, It is characterized in that The step S4 specifically includes the following method: Step 41: Constructing the Voltage Limiting Modulation Module: According to the inverter output voltage capability, when the voltage is greater than When , the voltage is limited and modulated: Step 42: Construct the Inverse Park Transform Module: Construct the inverse Park transformation from the rotating dq coordinate system to the stationary coordinate system: in, is the output voltage in the two-phase rotating coordinate system, U α ,U β It is the voltage output in the stationary coordinate system. According to the output voltage, combined with the two-level space vector modulation module, it outputs the switching signal to the three-phase inverter to drive the permanent magnet synchronous motor to operate.

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