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CN-116317752-B - Permanent magnet hub motor speed smooth switching control method in wide rotating speed range

CN116317752BCN 116317752 BCN116317752 BCN 116317752BCN-116317752-B

Abstract

The invention discloses a speed smooth switching control method of a permanent magnet hub motor in a wide rotating speed range, which comprises the steps of 1, establishing a first-order mechanical motion equation of the permanent magnet synchronous motor, 2, establishing a linear extended state observer LESO according to the first-order mechanical motion equation of the permanent magnet synchronous motor, establishing a tracking differentiator and a feedback control rule for realizing complete linear active disturbance rejection controller LADRC design, 3, improving the structure of the LESO, adopting a resonance integral extended state observer RI-ESO to enable the resonance integral extended state observer RI-ESO to observe sinusoidal disturbance and constant disturbance which occur in the motor control process at the same time, 4, adopting a method of switching RI-ESO input to ensure stable operation of the system in the wide rotating speed range and simultaneously ensure suppression capability of harmonic disturbance, and 5, when switching T e is used as the observer input, the value of the resonance gain can be properly increased, and the suppression capability of the harmonic can be adjusted according to actual conditions with the rising of the rotating speed.

Inventors

  • XIANG ZIXUAN
  • JIANG WENHAO
  • ZHU XIAOYONG
  • QUAN LI
  • ZUO YUEFEI

Assignees

  • 江苏大学

Dates

Publication Date
20260512
Application Date
20230314

Claims (6)

  1. 1. The method for controlling the smooth speed switching of the permanent magnet hub motor within a wide rotating speed range is characterized by comprising the following steps of: step 1, establishing a first-order mechanical motion equation of a permanent magnet synchronous motor; Step 2, a linear expansion state observer LESO is established according to a first-order mechanical motion equation of the permanent magnet synchronous motor, and a tracking differentiator and a feedback control law are established for realizing complete linear active disturbance rejection controller LADRC design; Step 3, improving the structure of the LESO, and adopting a resonance integral extended state observer RI-ESO to enable the resonance integral extended state observer RI-ESO to observe sinusoidal disturbance and constant disturbance in the motor control process at the same time; step 4, a method of switching RI-ESO input is adopted to ensure stable operation of the system in a wide rotating speed range, and meanwhile, the suppression capability of harmonic disturbance is ensured; Step 5, increasing the resonant gain when switching T e as observer input The suppression capability of the harmonic wave is improved along with the rising of the rotating speed, and the value is adjusted according to the actual situation.
  2. 2. The method for smoothly switching and controlling the speed of a permanent magnet hub motor within a wide rotating speed range according to claim 1, wherein the specific process of step 1 is as follows: firstly, a first-order mechanical motion equation of the permanent magnet synchronous motor is established as follows: (1); Wherein ω is the mechanical angular velocity of the motor rotor, rad/s, T e ,T L is the electromagnetic torque, the load torque, N.m, T r is the pulsating torque including the cogging torque caused by the motor body and the sixth order harmonic torque caused by the dead time of the inverter, T e * is the electromagnetic torque given value, B is the viscous friction coefficient, J is the moment of inertia, the control gain b=1/J, the total disturbance Regardless of the total disturbance of the torque tracking error 。
  3. 3. The method for smoothly switching and controlling the speed of a permanent magnet hub motor within a wide rotating speed range according to claim 1, wherein the specific process of the step 2 is as follows: the linear extended state observer LESO is established as follows: (1); In the formula, For measuring the error between the speed and the observed speed, delta n is the speed measurement noise, b=1/J is the control gain, the variable with the value is the estimated value, h 1, h 2 is the gain of the observer, and the observer parameter is determined to be the value according to the bandwidth method setting strategy , , Bandwidth for observer; in order to realize the complete linear active disturbance rejection controller LADRC design, a tracking differentiator and a feedback control rule are also needed, and in order to simplify the controller design and facilitate parameter setting, the linear tracking differentiator is ignored and a linear feedback control rule is adopted, and the linear feedback control rule is designed as follows: (3); Angular velocity of medium machinery And total disturbance Instead of their observations, the linear control law expressed by formula (3) is expressed as: (4); In the middle of For the speed loop reference input, The observation speed taken from the extended state observer, The observed perturbation taken from the extended state observer, Proportional gain for the controller; considering that an actual system cannot generate infinite output, the output torque also needs to be subjected to clipping processing, and the adopted clipping function is as follows: (5); In the middle of For the maximum torque reference to be available, Is the saturated torque reference.
  4. 4. The method for smoothly switching and controlling the speed of a permanent magnet hub motor within a wide rotation speed range according to claim 1, wherein in the step 3, the adopted resonance integral extended state observer RI-ESO has the following expression in s domain: (6); In the middle of To measure the error between the speed and the observed speed, As a speed observation, delta n is speed measurement noise, Is resonance gain, all are greater than 0, b=1/J is control gain, Is of resonant frequency, in For observations of constant or low frequency disturbances, For the observation value of harmonic disturbance, k 1, k 2 is the gain of the observer, and the bandwidth setting strategy is adopted, and the observer parameters are adopted , , Bandwidth for observer; the observer takes the form of an integrator for constant disturbances and a resonant controller for harmonic disturbances.
  5. 5. The method for smoothly switching and controlling the speed of a permanent magnet hub motor within a wide rotating speed range according to claim 1, wherein the specific process of the step 4 is as follows: when T e is used as an input to the observer, there are: (7); from the analysis, the closed loop transfer function Δ cl of the system is: (8); wherein T ci is the torque loop time constant, Is a characteristic polynomial of the lacc, For proportional gain of the controller, ω h is the resonant frequency, and k r is the resonant gain; according to the Hulvitz stability criterion, under the condition that delay exists in a torque ring, T e is adopted as the input of an observer, the system is constant and stable, but compared with the condition that T e * is adopted as the input of the observer, the stable operation of the system is ensured by adopting a switching input strategy, and meanwhile, the suppression capability of harmonic disturbance is ensured, wherein the suppression capability is shown in the following formula: (9); where u represents the observer input, At the maximum value of the resonant frequency, The limit value for the resonant frequency can be obtained off-line by calculating the stability condition: (10); Wherein C 1 ,B 1 ,A 1 is a parameter set for simplifying the expression, the specific expression is shown in the formula : 0(11); And In x, y, a, B, C, K, a 21 ,a 31 , B, C, d are also parameters set up to simplify the expression, in particular: (12); Wherein: (13); In the middle of For proportional gain of the controller, T ci is torque loop time constant, k 1, k 2 is gain of the observer, and k r is resonant gain; In the middle of The limit value for the resonant frequency can be obtained off-line by calculating the stability condition, For maximum resonance frequency, while suppressing 1 st, 2 nd and 6 th order torque ripple: (14); In the middle of Is polar logarithmic.
  6. 6. The method for smoothly switching speed of permanent magnet hub motor in wide rotation speed range according to claim 1, wherein in step 5, the adaptive gain is set The method comprises the following steps: (15); The electrical angular velocity, n is the mechanical rotor angular velocity, rpm, and a is the constant of the adaptive gain greater than 0.

Description

Permanent magnet hub motor speed smooth switching control method in wide rotating speed range Technical Field The invention relates to the technical field of control of permanent magnet hub motors, in particular to a permanent magnet hub motor speed smooth switching control strategy in a wide rotating speed range. Background In recent years, the permanent magnet hub motor (PMSHM) is widely applied to the field of direct driving, such as electric automobiles, electric propulsion, robots and the like, due to the advantages of simple structure, high reliability, high control precision and the like. However, in actual use of the permanent magnet in-wheel motor, torque pulsation is still inevitably present. There are many causes of torque ripple, such as cogging torque and magnetic flux harmonics caused by the motor body structure, inverter dead zone effects, and voltage and current harmonics caused by current measurement errors. Torque ripple directly causes rotational speed ripple, position ripple, especially for larger low-order torque ripple. In severe cases, even unstable system operation may result. Therefore, in order to ensure smooth regulation of speed and safe and reliable operation of the system, a certain method must be adopted to suppress torque pulsation. Aiming at the suppression of electromagnetic torque pulsation, the technical scheme adopted at present can be divided into two types, namely, the pulsation of electromagnetic torque is reduced from the structural design and optimization angles of a motor body, and the suppression of torque pulsation is realized through the design of a control algorithm. The torque pulsation scheme is restrained from the design of the motor body, so that the design and manufacturing complexity of the motor are increased, the manufacturing cost is increased, and the power density of the motor is affected. In addition, the optimal design of the motor body cannot overcome torque pulsation caused by drive controller harmonics. While torque ripple suppression is actively performed from the control point of view, the torque ripple suppression method has stronger flexibility and applicability compared with the method, although factors such as torque ripple information detection and control errors are difficult to completely eliminate. In summary, in view of the problem that PMSHM in practical applications, the rotational speed fluctuation caused by torque pulsation is even unstable in system operation, it is necessary to propose a speed smoothing control strategy to meet the motor operation requirement. Disclosure of Invention Based on the defects of the prior art, the invention provides a permanent magnet hub motor speed smooth switching control strategy in a wide rotating speed range, and the technical scheme of the invention is as follows: a permanent magnet hub motor speed smooth switching control method in a wide rotating speed range comprises the following steps: step 1, establishing a first-order mechanical motion equation of a permanent magnet synchronous motor; Step 2, a linear expansion state observer LESO is established according to a first-order mechanical motion equation of the permanent magnet synchronous motor, and a tracking differentiator and a feedback control law are established for realizing complete linear active disturbance rejection controller LADRC design; Step 3, improving the structure of LESO, adopting a Resonance integral extended state observer RI-ESO (Resonance-integral Extended State Observer) to enable the structure to observe sinusoidal disturbance and constant disturbance in the motor control process at the same time; step 4, a method of switching RI-ESO input is adopted to ensure stable operation of the system in a wide rotating speed range, and meanwhile, the suppression capability of harmonic disturbance is ensured; And 5, when the switch T e is used as an observer input, the value of the resonance gain k r can be properly increased, the harmonic suppression capability is improved along with the increase of the rotating speed, and the adjustment can be carried out according to the actual situation. Further, the specific process of the step1 is as follows: firstly, a first-order mechanical motion equation of the permanent magnet synchronous motor is established as follows: Wherein ω is the mechanical angular velocity of the motor rotor, rad/s, T e,TL is the electromagnetic torque, the load torque, N.m, T r is the pulsating torque mainly comprising the cogging torque caused by the motor body and the sixth order harmonic torque caused by the dead time of the inverter, T e* is the electromagnetic torque given value, B is the viscous friction coefficient, J is the moment of inertia, the control gain b=1/J, and the total disturbance The total disturbance f n＝-(Bω+Tr+TL)/J of the torque tracking error is not considered. Further, the specific process of the step 2 is as follows: the linear extended state observer LESO is established as follows