阅读说明：本技术 一种新的异步电机的转子磁链估计方法 (Novel rotor flux linkage estimation method of asynchronous motor ) 是由 黄自翔 曾智波 陈自强 于 2021-06-04 设计创作，主要内容包括：本发明公开了一种新的异步电机的转子磁链估计方法,属于电机控制技术领域,基于电压模型,采用自适应陷波器对异步电机进行转子磁链进行估算,获取转子的位置,进行异步电机FOC控制,本发明采用自适应陷波器代替电压模型的转子磁链观测器中的积分环节,相当于将积分从时域转换到频域,消除了积分初值对转子磁链估计的影响,使得基于电压模型的磁链观测器可以适用于全频率段。(The invention discloses a novel rotor flux linkage estimation method of an asynchronous motor, which belongs to the technical field of motor control, and is characterized in that a voltage model is based, an adaptive notch filter is adopted to estimate rotor flux linkage of the asynchronous motor, the position of a rotor is obtained, and FOC control of the asynchronous motor is carried out.)

1. A new rotor flux linkage estimation method of an asynchronous motor is characterized by comprising the following steps:

step 1, based on a voltage model, estimating a rotor flux linkage of an asynchronous motor by adopting an adaptive notch filter, obtaining the position of a rotor, and performing FOC control on the asynchronous motor, wherein the transfer function of the adaptive notch filter is shown as a formula (5):

where ω is the notch frequency, ω_cIs the trap bandwidth;

step 2, acquiring the frequency omega of the stator voltage of the asynchronous motor according to the following formulas (3) and (4), and then enabling the omega and the bandwidth omega of the wave trap_cFormula (5);

whereinAs two-phase stationary coordinatesThe magnetic linkage of the alpha-axis rotor is closed,is a beta axis rotor flux linkage u under a two-phase static coordinate system_saIs the stator voltage of the alpha axis u under a two-phase static coordinate system_sβIs the beta axis stator voltage under a two-phase static coordinate system, Rs is the stator resistance, Ls is the stator inductance,

step 3, dividing the output value of the formula (5) by-omega, reversing the phase and reducing the amplitude by omega times to obtain an integral output value;

step 4, adopting a rotor flux linkage direct magnetic field directional control with a speed sensor; wherein, the stator voltage is from given voltage, the stator current is from the actual sampling current of the motor, the motor speed is from the speed sensor, the stator voltage and the stator current are used as input, and the rotor flux linkage observer is used for obtaining the rotor flux linkageAndrotor flux linkage amplitudeRotor flux linkage angleAnd the amplitude of the obtained rotor flux linkage is used as flux linkage feedback of the magnetic chain link, and the angle of the rotor flux linkage is used as a position angle of park transformation and reverse park transformation, so that the direct magnetic field orientation control of the rotor flux linkage by using the adaptive notch filter is realized.

2. A new method for estimating the flux linkage of the rotor of an asynchronous machine according to claim 1, characterized in that the selection frequency is 50Hz, which is takenω＝100π，ω_cAt 1 pi, the trap does not attenuate in amplitude at 50Hz and lags the phase by 90 °.

3. A new rotor flux linkage estimation method of an asynchronous machine according to claim 2, characterized in that in the rotor flux linkage observer of the current model, the rotor flux linkage is estimatedThe amplitude calculation is shown in equation (1):wherein i_stIs a T-axis stator current, i_smFor M-axis stator current, rotor time constantL_rIs rotor inductance, R_rIs rotor resistance, L_mIs mutual inductance.

4. A new rotor flux linkage estimation method of an asynchronous machine according to claim 3, characterized in that in the rotor flux linkage observer of the current model, the rotor flux linkage is estimatedThe position calculation is shown in equation (2):wherein i_stIs a T-axis stator current, i_smFor M-axis stator current, rotor time constantL_rIs rotor inductance, R_rIs rotor resistance, L_mIs mutual inductance.

5. A new rotor flux linkage estimation method for an asynchronous machine according to claim 3, characterized in thatCharacterized in that a phase-locked loop PLL is used for acquiring the frequency omega of the stator voltage of the asynchronous motor, and then the frequency omega and the proper wave trap bandwidth omega are used_cThe formula (5) is given.

Technical Field

The invention relates to the technical field of motor control, in particular to a novel rotor flux linkage estimation method of an asynchronous motor.

Background

When the asynchronous motor carries out Field Oriented Control (FOC), the rotor flux linkage orientation is often used to carry out active and reactive decoupling of the rotor, thereby realizing high-performance control.

The rotor flux linkage orientation firstly needs to obtain the rotor flux linkage of the asynchronous motor, and commonly used rotor flux linkage observers of the asynchronous motor are divided into two types, namely a rotor flux linkage observer based on a current model and a rotor flux linkage observer based on a voltage model.

In the rotor flux linkage observer of the current model, formula (1) is rotor flux linkageAmplitude calculation, equation (2) being rotor flux linkageThe position calculation shows:

wherein i_stIs a T-axis stator current, i_smFor M-axis stator current, rotor time constantL_rIs rotor inductance, R_rIs rotor resistance, L_mIs mutual inductance.

The rotor flux linkage observer of the current model relates to rotor resistance parameters of the asynchronous motor, and the difficulty of rotor resistance identification of the asynchronous motor is high. In addition, the current model rotor flux linkage observer needs the rotating speed of the motor, and is quite unfavorable for the non-inductive FOC control of the asynchronous motor.

The rotor flux linkage observer of the voltage model is shown in formulas (3) and (4):

whereinIs an alpha-axis rotor flux linkage,is a beta axis rotor flux linkage, u_saIs the stator voltage of the alpha axis u_sβIs the stator voltage of the beta axis, Rs is the stator resistance, Ls is the stator inductance,

and the rotor flux observer of the voltage model does not relate to the rotor resistance of the asynchronous motor, so that the identification of the parameters of the asynchronous motor is facilitated. Meanwhile, the rotor flux linkage observer of the voltage model does not need actual rotating speed, and is very suitable for the non-inductive FOC of the asynchronous motor. However, because the rotor flux linkage observer of the voltage model has an integral link, the integral can be influenced by an integral initial value in a time domain, and the rotor flux linkage estimation can be seriously deviated.

Because the integral link is greatly influenced by an initial value of the integral, a first-order inertia link is generally adopted to replace the integral link in the rotor flux linkage observer based on the voltage model, but the characteristic of the first-order inertia link in a low frequency band is greatly different from that of the integral link, so that the conventional voltage model flux linkage observer cannot be used in the low frequency band.

The invention adopts the self-adaptive notch filter to replace an integral link in the rotor flux linkage observer of the voltage model, which is equivalent to converting the integral from a time domain to a frequency domain, and eliminates the influence of an integral initial value on rotor flux linkage estimation, so that the flux linkage observer based on the voltage model can be suitable for a full-frequency segment.

Disclosure of Invention

The present invention is directed to a new method for estimating rotor flux linkage of an asynchronous motor, so as to solve the problems mentioned in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

a new rotor flux linkage estimation method of an asynchronous motor comprises the following steps:

step 1, based on a voltage model, estimating a rotor flux linkage of an asynchronous motor by adopting an adaptive notch filter, obtaining the position of a rotor, and performing FOC control on the asynchronous motor, wherein the transfer function of the adaptive notch filter is shown as a formula (5):

where ω is the notch frequency, ω_cIs the trap bandwidth;

step 2, acquiring the frequency omega of the stator voltage of the asynchronous motor according to the following formulas (3) and (4), and then enabling the omega and the bandwidth omega of the wave trap_cFormula (5);

whereinIs an alpha-axis rotor flux linkage under a two-phase static coordinate system,is a beta axis rotor flux linkage u under a two-phase static coordinate system_saIs the stator voltage of the alpha axis u under a two-phase static coordinate system_sβIs the beta axis stator voltage under a two-phase static coordinate system, Rs is the stator resistance, Ls is the stator inductance,

step 3, dividing the output value of the formula (5) by-omega, reversing the phase and reducing the amplitude by omega times to obtain an integral output value;

step 4, adopting a rotor flux linkage direct magnetic field directional control with a speed sensor; wherein, the stator voltage is from given voltage, the stator current is from the actual sampling current of the motor, the motor speed is from the speed sensor, the stator voltage and the stator current are used as input, and the rotor flux linkage observer is used for obtaining the rotor flux linkageAndrotor flux linkage amplitudeRotor flux linkage angleAnd the amplitude of the obtained rotor flux linkage is used as flux linkage feedback of the magnetic chain link, and the angle of the rotor flux linkage is used as a position angle of park transformation and reverse park transformation, so that the direct magnetic field orientation control of the rotor flux linkage by using the adaptive notch filter is realized.

As a further technical scheme of the invention: when the frequency is 50Hz, the frequency is 100 pi, omega_cAt 1 pi, the trap does not attenuate in amplitude at 50Hz and lags the phase by 90 °.

As a further technical scheme of the invention: in a rotor flux linkage observer of a current model, rotor flux linkageThe amplitude calculation is shown in equation (1):wherein i_stIs a T-axis stator current, i_smFor M-axis stator current, rotor time constantL_rIs rotor inductance, R_rIs rotor resistance, L_mIs mutual inductance.

As a further technical scheme of the invention: in a rotor flux linkage observer of a current model, rotor flux linkageThe position calculation is shown in equation (2):wherein i_stIs a T-axis stator current, i_smFor M-axis stator current, rotor time constantL_rIs rotor inductance, R_rIs rotor resistance, L_mIs mutual inductance.

As a further technical scheme of the invention: the frequency omega of the stator voltage of the asynchronous motor is obtained by a phase-locked loop (PLL), and then the omega and the proper wave trap bandwidth omega are obtained_cThe formula (5) is given.

Compared with the prior art, the invention has the beneficial effects that: the invention adopts the self-adaptive notch filter to replace an integral link in the rotor flux linkage observer of the voltage model, which is equivalent to converting the integral from a time domain to a frequency domain, and eliminates the influence of an integral initial value on rotor flux linkage estimation, so that the flux linkage observer based on the voltage model can be suitable for a full-frequency segment.

Drawings

Figure 1 is a bode diagram of a trap.

FIG. 2 is a block diagram of a rotor flux linkage observer using an adaptive notch filter based on a voltage model.

FIG. 3 is a schematic diagram of a rotor flux linkage direct field orientation control of an asynchronous machine using an adaptive notch filter.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: referring to fig. 1-3, a new method for estimating rotor flux linkage of an asynchronous motor comprises the following steps:

step 1, based on a voltage model, estimating a rotor flux linkage of an asynchronous motor by adopting an adaptive notch filter, obtaining the position of a rotor, and performing FOC control on the asynchronous motor, wherein the transfer function of the adaptive notch filter is shown as a formula (5):

where ω is the notch frequency, ω_cFor the bandwidth of the wave trap, let ω be 100 pi, ω when the frequency is selected to be 50Hz_cThe bode diagram of the trap is shown in fig. 1, with no attenuation in amplitude at 50Hz and a 90 ° phase lag, and can therefore be used to model the frequency domain characteristics of the integration.

Step 2, according to the following formulas (3) and (4), acquiring the frequency omega of the stator voltage of the asynchronous motor by adopting a phase-locked loop PLL (phase-locked loop), and then combining the omega and the wave trap bandwidth omega_cFormula (5);

whereinIs an alpha-axis rotor flux linkage under a two-phase static coordinate system,is a beta axis rotor flux linkage u under a two-phase static coordinate system_saIs the stator voltage of the alpha axis u under a two-phase static coordinate system_sβIs the beta axis stator voltage under a two-phase static coordinate system, Rs is the stator resistance, Ls is the stator inductance,

step 3, as shown in fig. 1, it can be known that to obtain an equivalent integral output, the output value of the formula (5) needs to be divided by- ω, the phase is reversed, and the amplitude is reduced by ω times, which is the integral output;

and 4, the asynchronous motor adopts the rotor flux linkage direct magnetic field orientation control of the adaptive notch filter as shown in figure 3, wherein the rotor flux linkage direct magnetic field orientation control with a speed sensor is adopted. The stator voltage is from a given voltage, the stator current is from the actual sampled current of the motor, and the motor speed is from a speed sensor. The rotor flux linkage can be obtained by using the stator voltage and the stator current as input through the method shown in the block diagram 2Androtor flux linkage amplitudeRotor flux linkage angleAnd an angle. The amplitude of the obtained rotor flux linkage is used as flux linkage feedback of the flux linkage, and the angle of the rotor flux linkage is used as a position angle of park transformation and reverse park transformation, so that the direct magnetic field orientation control of the rotor flux linkage by using the self-adaptive notch filter can be realized.

Embodiment 2, on the basis of embodiment 1, in order to realize the replacement of the integral, a phase-locked loop (PLL) is used for acquiring the frequency omega of the stator voltage of the asynchronous motor, and then the omega and the proper wave trap bandwidth omega are combined_cThe formula (5) is given.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.