Current harmonic online rapid calculation method for vibration suppression of permanent magnet synchronous motor

Abstract

The invention discloses a current harmonic online rapid calculation method for vibration suppression of a permanent magnet synchronous motor, and belongs to the field of motor control. At present, an optimal current acquisition method adopted for suppressing radial vibration of a permanent magnet synchronous motor generally depends on manual off-line optimization, is low in efficiency and is easily influenced by mechanical installation conditions of the motor and actual operation environment changes, so that the suppression effect is difficult to keep stable. In order to solve the problem, the invention provides an online optimization method. The method comprises the following steps: injecting three groups of current harmonics with different phases and equal amplitudes into a motor; respectively acquiring an initial state and an injected vibration signal by using a vibration sensor arranged on a motor shell; an equation set is established according to the function relation between the current harmonic waves and the vibration signals, and then the amplitude and the phase of the optimal current harmonic waves are obtained through online rapid solving. The method is simple in structure and easy to implement, the optimal solution of the current harmonics can be rapidly solved, and the real-time performance and adaptability of vibration suppression are effectively improved.

Description

Technical Field

[0001] This invention relates to a method for rapid online calculation of current harmonics for vibration suppression of permanent magnet synchronous motors, belonging to the field of motor control. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in industrial and consumer applications due to their high performance; however, vibration and noise problems caused by electromagnetic forces during operation are becoming increasingly prominent. Traditional mechanical vibration reduction methods are costly and lack flexibility. With the development of digital control technology, current harmonic injection based on control strategies has become a highly efficient solution. This method actively cancels the electromagnetic excitation source that generates vibration by injecting specific harmonics into the stator current, thereby suppressing vibration at its source. This technology achieves performance optimization through software algorithms, and has the advantages of low cost and strong adaptability, representing a cutting-edge research direction for improving the quiet and smooth operation performance of high-end motors.

[0003] Numerous studies, both domestically and internationally, have explored low-frequency vibration suppression in motors based on current harmonic injection. Two main methods exist: one involves manually injecting different current harmonics to find the optimal amplitude and phase; the other transforms manual optimization into online optimization using a gradient descent algorithm. The paper "Noise Reduction Via Harmonic Current Injection for Concentrated-Winding Permanent Magnet Synchronous Machines" (21st International Conference on Electrical Machines and Systems (ICEMS), 2018) found the optimal injection amplitude and phase for the 7th harmonic current, demonstrating a 30dB reduction in the 6th harmonic vibration of the tested motor. The paper "Online control strategy for radial vibration suppression of PMSM by Multiharmonic current injection method" (IEEE Transactions on Industrial Electronics, 2022) uses gradient descent to calculate online the frequency, amplitude, and phase of the injected current harmonic when the radial vibration harmonic amplitude is minimized, showing that this method effectively suppresses the motor's radial vibration. Existing current harmonic optimization methods primarily suffer from the problem of excessive time consumption. Summary of the Invention

[0004] This invention addresses the problem of time-consuming existing current harmonic optimization methods by proposing an online rapid calculation method for current harmonics in permanent magnet synchronous motor vibration suppression.

[0005] To achieve the above method, the present invention employs the following... Figure 1 The control system shown includes an optimal current harmonic online calculation module, an SVPWM module, a VSI module, a permanent magnet synchronous motor, and a current harmonic injection module.

[0006] The control system has the following structure:

[0007] The input to the optimal current harmonic online calculation module is the vibration signal F collected from the permanent magnet synchronous motor. S F1, F2, F3, where F S F1 represents the vibration amplitude without current harmonic injection, while F2 and F3 represent the vibration amplitudes after injecting three current harmonics with the same amplitude but different phases, respectively. The output of the optimal current harmonic online calculation module is transformed by Clark and Park to obtain its reference current i in the dq coordinate system. best-d i best-q It is also used as the reference current for the current harmonic injection module.

[0008] The input to the current harmonic injection module is the phase current i of the permanent magnet synchronous motor. ABC In the dq rotating coordinate system, the k-th current harmonic is an AC component. However, after a corresponding coordinate transformation, the phase current is transformed to the k-th dq rotating coordinate system, where the k-th current harmonic becomes a DC component. The fundamental frequency and other harmonics then become AC components. A low-pass filter (LPF) removes the remaining AC components, yielding the corresponding DC component, which is used as the measured value. The measured value is then compared with the given value i. best-d i best-q The error obtained by subtraction is processed by a proportional-integral controller and the corresponding k-th inverse Park transform to obtain the k-th voltage u on the αβ axis. best-α u best-β Finally, the voltage u best-α u best-β The compensation is added to the reference signal of the SVPWM module.

[0009] The SVPWM module is a space vector pulse width modulation module, and its input is the reference voltage u on the αβ axis. ref-α u ref-β With the output u of the current harmonic injection module best-α u best-β The pulse width modulation signal (PWM wave) output by the SVPWM module. A S B S CAs input to the VSI module; the VSI module is a power electronic device-based inverter whose output provides three-phase current to the permanent magnet synchronous motor.

[0010] The optimal current calculation method is to use the functional relationship between the amplitude and phase of the k-th current harmonic and the vibration, inject three different current harmonics and establish functional equations, and calculate the initial phase of the radial vibration by solving the system of functional equations (1). and the radial vibration phase after the injection of the first current harmonic and the phase of the radial vibration it produces

[0011]

[0012] in θ1, θ2, and θ3 are the phases of the radial vibration after the injection of three different current harmonics, respectively. θ1, θ2, and θ3 are the phases of the three injected current harmonics, x is the component of the radial vibration vector generated by the first injected current harmonic on the real axis, and y is the component of the radial vibration vector generated by the first injected current harmonic on the imaginary axis.

[0013] Then, the amplitude I of the optimal current harmonic is solved using equation system (2). best and phase θ best .

[0014]

[0015] Among them, F k It is the amplitude of the radial vibration generated by the injected first current harmonic, I k It represents the amplitude of the three injected current harmonics.

[0016] The formula for the three-phase current of the k-th harmonic is as follows:

[0017]

[0018] In the formula, k represents the harmonic order of the current, k = 6n + 1, n = ±1, ±2…. ω e I is the electrical angular frequency of the motor. k Let θ be the amplitude of the kth current harmonic. k The phase of the k-th current harmonic.

[0019] The optimal current harmonic amplitude I obtained by solving equation (2) best and phase θ best Substituting into equation (3), and then obtaining the reference current i in the dq coordinate system through Clark transformation and k-th Park transformation. best-d i best-q As shown in equation (4).

[0020] Attached Figure Description

[0021] Figure 1 This is a system structure diagram of the online rapid calculation method for current harmonics in a permanent magnet synchronous motor vibration suppression method according to the present invention. Detailed Implementation

[0022] This invention provides a method for rapid online calculation of current harmonics for vibration suppression of permanent magnet synchronous motors, and the method is further described in detail with reference to the accompanying drawings.

[0023] To achieve the above method, the present invention employs the following... Figure 1 The control system shown is implemented by including: an optimal current harmonic online calculation module (1), an SVPWM module (2), a VSI module (3), a permanent magnet synchronous motor (4), and a current harmonic injection module (5).

[0024] The input to the optimal current harmonic online calculation module (1) is the vibration signal F collected from the permanent magnet synchronous motor (4). S F1, F2, F3, where F S F1, F2, and F3 are the vibration amplitudes when no current harmonics are injected, respectively, and F1, F2, and F3 are the vibration amplitudes after injecting three current harmonics with the same amplitude but different phases. The output of the optimal current harmonic online calculation module (1) is transformed by Clark and Park to obtain its reference current i in the dq coordinate system. best-d i best-q And it serves as the reference current for the current harmonic injection module (5).

[0025] The current harmonic injection module (5) receives the phase current i of the permanent magnet synchronous motor (4) as input. ABC In the dq rotating coordinate system, the k-th current harmonic is an AC component. However, after a corresponding coordinate transformation, the phase current is transformed to the k-th dq rotating coordinate system, where the k-th current harmonic becomes a DC component. The fundamental frequency and other harmonics then become AC components. A low-pass filter (LPF) removes the remaining AC components, yielding the corresponding DC component, which is used as the measured value. The measured value is then compared with the given value i. best-d i best-q The error obtained by subtraction is processed by a proportional-integral controller and the corresponding k-th inverse Park transform to obtain the k-th voltage u on the αβ axis. best-α u best-β Finally, the voltage u best-α u best-β The compensation is added to the reference signal of the SVPWM module (2).

[0026] The SVPWM module (2) is a space vector pulse width modulation module, and its input is the reference voltage u on the αβ axis. ref-α u ref-β The output u of the current harmonic injection module (5) best-α u best-β The pulse width modulation signal S output by the SVPWM module (2) is a pulse width modulation signal. A S B S C As the input of the VSI module (3); the VSI module (3) is an inverter based on power electronic devices, whose output provides three-phase current to the permanent magnet synchronous motor (4).

[0027] The optimal current calculation method is to use the functional relationship between the amplitude and phase of the k-th current harmonic and radial vibration, inject three different current harmonics and establish functional equations, and calculate the initial phase of radial vibration by solving the system of functional equations (1). and the radial vibration phase after the injection of the first current harmonic and the phase of the radial vibration it produces

[0028] in θ1, θ2, and θ3 are the phases of the radial vibration after the injection of three different current harmonics, respectively. θ1, θ2, and θ3 are the phases of the three injected current harmonics, x is the component of the radial vibration vector generated by the first injected current harmonic on the real axis, and y is the component of the radial vibration vector generated by the first injected current harmonic on the imaginary axis.

[0029] Then, the amplitude I of the optimal current harmonic is solved using equation system (2). best and phase θ best

[0030]

[0031] Among them, F k It is the amplitude of the radial vibration generated by the injected first current harmonic, I k It represents the amplitude of the three injected current harmonics.

[0032] The formula for the three-phase current of the k-th harmonic is as follows:

[0033]

[0034] In the formula, k represents the harmonic order of the current, k = 6n + 1, n = ±1, ±2…. ω e I is the electrical angular frequency of the motor. k Let θ be the amplitude of the kth current harmonic. k The phase of the k-th current harmonic.

[0035] The optimal current harmonic amplitude I obtained by solving equation (2) best and phase θ best Substituting into equation (3), and then obtaining the reference current i in the dq coordinate system through Clark transformation and k-th Park transformation. best-d i best-q As shown in equation (4).

[0036]

[0037] The core of this invention lies in the design of the optimal online current harmonic calculation module (1). It innovatively utilizes the functional relationship between current harmonics and vibration to establish a system of equations. Then, by solving the equations, the optimal injection amplitude and phase of the current harmonics are obtained, achieving rapid online optimization of the current harmonics. Furthermore, depending on the sensor's accuracy, when the sensor cannot accurately measure the phase of the vibration, three injected current harmonics can be used to solve the equations; when the sensor can directly and accurately measure the phase of the vibration, only one injected current harmonic can be used to solve the equations.

Claims

1. A method for rapid online calculation of current harmonics for vibration suppression of permanent magnet synchronous motors, characterized in that: The control system of the method includes: an optimal current harmonic online calculation module (1), an SVPWM module (2), a VSI module (3), a permanent magnet synchronous motor (4), and a current harmonic injection module (5); The input to the optimal current harmonic online calculation module (1) is the vibration signal F collected from the permanent magnet synchronous motor (4). S F1, F2, F3, where F S F1, F2, and F3 are the vibration amplitudes when no current harmonics are injected, respectively, and F1, F2, and F3 are the vibration amplitudes after injecting three current harmonics with the same amplitude but different phases. The output of the optimal current harmonic online calculation module (1) is transformed by Clark and k Park transformations to obtain its reference current i in the dq coordinate system. best-d i best-q And it serves as the reference current for the current harmonic injection module (5); The current harmonic injection module (5) receives the phase current i of the permanent magnet synchronous motor (4) as input. ABC In the dq rotating coordinate system, the k-th current harmonic is an AC component. However, after a corresponding coordinate transformation, the phase current is transformed to the k-th dq rotating coordinate system, where the k-th current harmonic becomes a DC component. The fundamental frequency and other harmonics then become AC components. A low-pass filter (LPF) removes the remaining AC components, yielding the corresponding DC component, which is used as the measured value. The measured value is then compared with the given value i. best-d i best-q The error obtained by subtraction is processed by a proportional-integral controller and the corresponding k-th inverse Park transform to obtain the k-th voltage u on the αβ axis. best-α u best-β Finally, the voltage u best-α u best-β The compensation is added to the reference signal of the SVPWM module (2); The SVPWM module (2) is a space vector pulse width modulation module, and its input is the reference voltage u on the αβ axis. ref-α u ref-β The output u of the current harmonic injection module (5) best-α u best-β The pulse width modulation signal S output by the SVPWM module (2) is a pulse width modulation signal. A S B S C As the input of the VSI module (3); the VSI module (3) is an inverter based on power electronic devices, whose output provides three-phase current to the permanent magnet synchronous motor (4).

2. The rapid online calculation method for low-frequency vibration suppression of permanent magnet synchronous motors based on current harmonic injection according to claim 1, characterized in that, Based on the functional relationship between the amplitude and phase of the k-th current harmonic and vibration, three different current harmonics are injected and functional equations are established. The initial phase of radial vibration is calculated by solving the system of functional equations (1). and the radial vibration phase after the injection of the first current harmonic and the phase of the radial vibration it produces in θ1, θ2, and θ3 are the phases of the radial vibration after the injection of three different current harmonics, respectively. θ1, θ2, and θ3 are the phases of the three injected current harmonics, x is the component of the radial vibration vector generated by the first injected current harmonic on the real axis, and y is the component of the radial vibration vector generated by the first injected current harmonic on the imaginary axis. Then, the amplitude I of the optimal current harmonic is solved using equation system (2). best and phase θ best Among them, F k It is the amplitude of the radial vibration generated by the injected first current harmonic, I k It represents the amplitude of the three injected current harmonics.

3. According to the rapid online calculation method for low-frequency vibration suppression of permanent magnet synchronous motors based on current harmonic injection as described in claim 1, the three-phase current formula for the k-th current harmonic is as follows: In the formula, k is the harmonic order of the current, k = 6n + 1, n = ±1, ±2…; ω e I is the electrical angular frequency of the motor. k Let θ be the amplitude of the kth current harmonic. k The phase of the k-th current harmonic; The optimal current harmonic amplitude I obtained by solving equation (2) best and phase θ best Substituting into equation (3), and then obtaining the reference current i in the dq coordinate system through Clark transformation and k-th Park transformation. best-d i best-q As shown in equation (4); If the vibration phase can be accurately measured, the amplitude and phase of the optimal current harmonic can be obtained by injecting a current harmonic. That is, after injecting a current harmonic, the equation system (2) can be solved directly without solving the equation system (1).

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