阅读说明：本技术 一种异步牵引电机定子电阻在线检测方法 (Asynchronous traction motor stator resistance on-line detection method ) 是由 张静萌 陈鸿蔚 周志华 曾志超 于 2019-12-17 设计创作，主要内容包括：本发明公开了一种异步牵引电机定子电阻在线检测方法,包括以下步骤：输出高频三相交流电到异步电机端；计算总功率；计算总电流的平方；计算Rsd,计算定子电阻自适应模型的初始值；计算出电压型转子磁链<Image he="77" wi="114" file="DDA0002321182070000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>计算出电流型转子磁链<Image he="78" wi="104" file="DDA0002321182070000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>利用<Image he="78" wi="90" file="DDA0002321182070000013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>与<Image he="81" wi="82" file="DDA0002321182070000014.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>的差值,作为参考自适应模型的输入,将<Image he="78" wi="89" file="DDA0002321182070000015.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>作为可调模型,<Image he="77" wi="85" file="DDA0002321182070000016.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>作为参考模型,自适应模型输出定子电阻值后,再反馈到可调模型中更新阻值,然后再进行计算,整个过程不停使可调模型跟踪参考模型,直至<Image he="77" wi="96" file="DDA0002321182070000017.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>与<Image he="75" wi="81" file="DDA0002321182070000018.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>的偏差趋于零,此时计算出的定子电阻作为准确真实值。本发明采用自适应参考模型在线测试定子阻值,并将计算得到的结果,实时更新到矢量控制或直接转矩控制算法中,可以有效地保证电机控制策略的准确输出。(The invention discloses an asynchronous traction motor stator resistance on-line detection method, which comprises the following steps: outputting high-frequency three-phase alternating current to an asynchronous motor end; calculating the total power; calculating the square of the total current; calculating Rsd and calculating an initial value of the stator resistance self-adaptive model; calculating voltage type rotor flux linkage Calculating current type rotor flux linkage By using And as input to the reference adaptive model will be As an adjustable model, the model can be, as a reference model, after the stator resistance value is output by the self-adaptive model, the stator resistance value is fed back to the adjustable model to update the resistance value, then the calculation is carried out, and the adjustable model continuously tracks the reference model in the whole process until the reference model is obtained And the deviation of (a) tends to zero, and the calculated stator resistance at this time is taken as an accurate true value. The method adopts the self-adaptive reference model to test the resistance value of the stator on line, and updates the calculated result into a vector control algorithm or a direct torque control algorithm in real time, thereby effectively ensuring the accurate output of a motor control strategy.)

1. An asynchronous traction motor stator resistance on-line detection method comprises the following steps:

1) firstly, outputting high-frequency three-phase alternating current to an asynchronous motor end through a traction converter for 10 cycles;

2) under a high-frequency mode, calculating the total power sigma P in the last 5 periods;

3) in this high-frequency mode, the motor current is measured by the current sensor, the total current Σ I in the last 5 cycles is calculated, and the square (∑ I) of the total current Σ I is calculated²；

4) Using total power sigma P and the square of total current sigma I (sigma I)²Calculating the resistance of the stator and the rotor of the motor in a high-frequency mode and an initial value Rsd, and subtracting the RsdObtaining an initial value Rs _ Init of the self-adaptive model of the stator resistance by a rotor resistance design value Rr;

5) utilizing initial value Rs _ Init of stator resistance and axis voltage V of stator α_sαStator β shaft voltage V_sβStator α shaft current i_sαStator β shaft current i_sβCalculating voltage type rotor flux linkage through rotor flux linkage voltage model

6) Using motor speed signal omega_mStator α shaft current i_sαStator β shaft current i_sβCalculating the current type rotor flux linkage through the rotor flux linkage current model

7) Using voltage-type rotor flux linkage

2. The asynchronous traction motor stator resistance online detection method according to claim 1, wherein in the step 1), the traction converter outputs a fixed frequency of F and an excitation current of i_sd ^*Torque current is i_sq ^*The output U, V, W three-phase sine is equal in size, 120 degrees in phase difference and 10 cycles are output when the three-phase alternating current is applied to the end of an asynchronous motor, wherein F is 4-6 times of the rated frequency fr of the asynchronous motor, i is_sd ^*Is 0.2-0.4 times of rated current Ir of the asynchronous motor_sq ^*Is 0.

3. The asynchronous traction motor stator resistance online detection method according to claim 1, wherein in the step 2), P ═ V (V ═ V)_sdi_sd+V_sqi_sq)，i_sdIs stator d-axis current, i_sqFor stator q-axis current, V_sdIs stator d-axis voltage, V_sqIs the stator q-axis voltage.

4. The asynchronous traction motor stator resistance online detection method according to claim 3, characterized in that in the step 2), stator d-axis current i_sdStator q-axis current i_sqThe obtaining method is as follows: firstly, three-phase currents iu, iv and iw of the motor are collected through a current sensor, and then i under a static coordinate system is obtained through Clarck transformation_sαi_sβThen, the i is obtained through Park transformation_sd，i_sq。

5. The asynchronous traction motor stator resistance online detection method according to claim 3, characterized in that in the step 2), stator d-axis voltage V_sdStator q-axis voltage V_sqThe obtaining method is as follows: firstly, obtaining three-phase voltage V of a stator through a voltage reconstruction algorithm_u、V_v、V_wThen obtaining V under a static coordinate system through Clarck transformation_sα、V_sβThen obtaining V through Park transformation_sd，V_sq。

6. The asynchronous traction motor stator resistance on-line detection method according to claim 3, wherein in the step 3), the square calculation formula of the total current Σ I is: (SigmaI)²＝∑(i_sd ²+i_sq ²)。

7. The asynchronous traction motor stator resistance on-line detection method according to claim 3, wherein in the step 4), Rsd is obtained by dividing the total power by the square of the total current, i.e. Rsd ∑ P/(∑ I)²。

8. The asynchronous traction motor stator resistance online detection method according to claim 3, wherein in the step 7), the adaptive law of the reference adaptive model is an integral type, that is:

Technical Field

The invention relates to the field of motor control, in particular to an online detection method for stator resistance of an asynchronous traction motor.

Background

In the control process of the asynchronous traction motor, the parameters of the motor have great influence on the performance of a control system, particularly the stator resistance of the motor is influenced by factors such as temperature and the like, and the asynchronous traction motor has the characteristics of uncertainty, nonlinearity and the like. In the control strategy of the asynchronous traction motor, no matter a vector control algorithm or a direct torque control algorithm is adopted, calculation is required to be introduced into the stator resistance of the motor, and if the motor parameter has large deviation, the control performance of the asynchronous traction motor can be greatly reduced, and even the function and the stability of the whole electric transmission system are affected. Therefore, the measurement of internal parameters of the asynchronous motor, particularly the stator resistance, is required to achieve accurate control of the asynchronous traction motor.

At present, in the prior art, a method for identifying parameters of an asynchronous traction motor generally adopts model reference self-adaptation, and the method continuously adjusts and updates parameters in a model through deviation between input and output quantities, thereby realizing parameter measurement. In practical operation, the input of initial parameters is important, if the deviation is overlarge, the time for the adaptive calculation process to reach a stable equilibrium state is long, and the selection of a reference model and an adaptive model is also critical, so that the whole control process is influenced.

Disclosure of Invention

In order to solve the technical problems, the invention provides the asynchronous traction motor stator resistance online detection method which is simple in algorithm and high in detection precision.

The technical scheme for solving the problems is as follows: an asynchronous traction motor stator resistance on-line detection method comprises the following steps:

1) firstly, outputting high-frequency three-phase alternating current to an asynchronous motor end through a traction converter for 10 cycles;

2) under a high-frequency mode, calculating the total power sigma P in the last 5 periods;

3) in this high-frequency mode, the motor current is measured by the current sensor, the total current Σ I in the last 5 cycles is calculated, and the square (∑ I) of the total current Σ I is calculated²；

4) Using total power sigma P and the square of total current sigma I (sigma I)²Calculating the resistance of a stator and a rotor of the motor in a high-frequency mode and an initial value Rsd, and subtracting a rotor resistance design value Rr from the obtained Rsd to obtain an initial value Rs _ Init of the self-adaptive model of the stator resistance;

5) utilizing initial value Rs _ Init of stator resistance and axis voltage V of stator α_sαStator β shaft voltage V_sβStator α shaft current i_sαStator β shaft current i_sβCalculating voltage type rotor flux linkage through rotor flux linkage voltage model

6) Using motor speed signal omega_mStator α shaft current i_sαStator β shaft current i_sβCalculating the current type rotor flux linkage through the rotor flux linkage current model

7) Using voltage-type rotor flux linkage

With current-type rotor flux linkage

As input of the reference adaptive model, the voltage-mode rotor flux linkage

As an adjustable model, current-mode rotor flux linkage

As a reference model, after the self-adaptive model outputs the stator resistance value, the stator resistance value is fed back to the adjustable model to update the resistance value, then the calculation is carried out, and the adjustable model is continuously made to track the reference model in the whole process until the voltage type rotor flux linkage is realized

With current-type rotor flux linkage

The deviation of (a) tends to zero, and the calculated stator resistance at this time is taken as an accurate true value.

In the above method for detecting the stator resistance of the asynchronous traction motor on line, in the step 1), the traction converter outputs a fixed frequency of F and an exciting current of i_sd ^*Torque current is i_sq ^*The output U, V, W three-phase sine is equal in size, 120 degrees in phase difference and 10 cycles are output when the three-phase alternating current is applied to the end of an asynchronous motor, wherein F is 4-6 times of the rated frequency fr of the asynchronous motor, i is_sd ^*Is 0.2-0.4 times of rated current Ir of the asynchronous motor_sq ^*Is 0.

In the above method for online detection of stator resistance of asynchronous traction motor, in step 2), P ═ V (V)_sdi_sd+V_sqi_sq)，i_sdIs stator d-axis current, i_sqFor stator q-axis current, V_sdIs stator d-axis voltage, V_sqIs the stator q-axis voltage.

In the above method for on-line detection of the stator resistance of the asynchronous traction motor, in the step 2), the stator resistance is determinedSub d-axis current i_sdStator q-axis current i_sqThe obtaining method is as follows: firstly, three-phase currents iu, iv and iw of the motor are collected through a current sensor, and then i under a static coordinate system is obtained through Clarck transformation_sαi_sβThen, the i is obtained through Park transformation_sd，i_sq。

In the above method for on-line detection of the stator resistance of the asynchronous traction motor, in the step 2), the d-axis voltage V of the stator_sdStator q-axis voltage V_sqThe obtaining method is as follows: firstly, obtaining three-phase voltage V of a stator through a voltage reconstruction algorithm_u、V_v、V_wThen obtaining V under a static coordinate system through Clarck transformation_sα、V_sβThen obtaining V through Park transformation_sd，V_sq。

In the above online detection method for the stator resistance of the asynchronous traction motor, in the step 3), the square calculation formula of the total current Σ I is: (SigmaI)²＝∑(i_sd ²+i_sq ²)。

In the above method for detecting stator resistance of asynchronous traction motor, in step 4), Rsd is obtained by dividing total power by the square of total current, that is, Rsd ═ Σ P/(Σi)²。

In the above online detection method for stator resistance of asynchronous traction motor, in step 7), the adaptive law with reference to the adaptive model is an integral type, that is:

is a vector of the current of the stator of the motor,

is cross-multiplied, kr is an integral coefficient,I_rmsis the effective value of the motor current, T_sFor a sampling period, R_sThe stator resistance value, t is time.

The invention has the beneficial effects that:

1. the method adopts the rotor flux linkage to identify the parameters of the stator resistance, the rotor flux linkage model is simple and has small calculated amount, the accuracy is improved, the stator resistance in the initial rotor flux linkage calculation is obtained by adopting a high-frequency mode, and the accuracy of the self-adaptive model is effectively ensured.

2. By adopting the invention, the algorithm module can be very easily embedded in a traction torque control strategy of the motor, and the traction converter is utilized without extra hardware cost. When the frequency converter works each time, the resistance value of the stator is tested on line by adopting the self-adaptive reference model, and the calculated result is updated to the vector control algorithm or the direct torque control algorithm in real time, so that the accurate output of the motor control strategy can be effectively ensured.

Drawings

FIG. 1 is a flow chart of the present invention.

Detailed Description

The invention is further described below with reference to the figures and examples.

As shown in fig. 1, an online detection method for stator resistance of an asynchronous traction motor includes the following steps:

1) firstly, outputting high-frequency three-phase alternating current to the end of an asynchronous motor through a traction converter for 10 cycles.

The traction converter outputs a fixed frequency F and an exciting current i_sd ^*Torque current is i_sq ^*The output U, V, W three-phase sine is equal in size, 120 degrees in phase difference and 10 cycles are output when the three-phase alternating current is applied to the end of an asynchronous motor, wherein F is 4-6 times of the rated frequency fr of the asynchronous motor, i is_sd ^*Is 0.2-0.4 times of rated current Ir of the asynchronous motor_sq ^*Is 0. Because the frequency F of the output three-phase alternating current is very high and the value of the frequency F is far greater than the rated frequency of the motor, the motor can completely run outside the hard characteristic field.

2) Under a high-frequency mode, calculating the total power sigma P in the last 5 periods; the first 5 cycles are the initial stagesThe sum calculation is not performed because of unstable sampling errors and other conditions. P ═ V_sdi_sd+V_sqi_sq)，i_sdIs stator d-axis current, i_sqFor stator q-axis current, V_sdIs stator d-axis voltage, V_sqIs the stator q-axis voltage.

Stator d-axis current i_sdStator q-axis current i_sqThe obtaining method is as follows: firstly, three-phase currents iu, iv and iw of the motor are collected through a current sensor, and then i under a static coordinate system is obtained through Clarck transformation_sαi_sβThen, the i is obtained through Park transformation_sd，i_sq。

In the step 2), the d-axis voltage V of the stator_sdStator q-axis voltage V_sqThe obtaining method is as follows: firstly, obtaining three-phase voltage V of a stator through a voltage reconstruction algorithm_u、V_v、V_wThen obtaining V under a static coordinate system through Clarck transformation_sα、V_sβThen obtaining V through Park transformation_sd，V_sq。

3) In this high-frequency mode, the motor current is measured by the current sensor, the total current Σ I in the last 5 cycles is calculated, and the square (∑ I) of the total current Σ I is calculated²；(∑I)²＝∑(i_sd ²+i_sq ²)。

4) Using total power sigma P and the square of total current sigma I (sigma I)²Calculating the resistance of the stator and rotor of the motor in the high-frequency mode and an initial value Rsd, wherein Rsd is obtained by dividing the total power by the square of the total current, namely Rsd is sigma P/(sigmaI)². And subtracting the rotor resistance design value Rr from the obtained Rsd to obtain an initial value Rs _ Init of the stator resistance self-adaptive model.

5) Utilizing initial value Rs _ Init of stator resistance and axis voltage V of stator α_sαStator β shaft voltage V_sβStator α shaft current i_sαStator β shaft current i_sβCalculating voltage type rotor flux linkage through rotor flux linkage voltage model

The rotor flux linkage voltage model refers to a calculation formula of voltage type rotor flux linkage, and the calculation formula is a common formula as follows:

6) using motor speed signal omega_mStator α shaft current i_sαStator β shaft current i_sβCalculating the current type rotor flux linkage through the rotor flux linkage current model

The rotor flux linkage current model refers to a calculation formula of current type rotor flux linkage, and the calculation formula is a common formula as follows:

7) using voltage type rotor magnetic pins

Current-type rotor magnetic pin

As input of the reference adaptive model, the voltage-mode rotor flux linkage

As adjustable model, current-mode rotor magnetic pin

As a reference model, the self-adaptive model outputs the stator resistance value and then feeds back the stator resistance value to the modelUpdating resistance values in the adjusting model, then calculating, and enabling the adjustable model to track the reference model continuously in the whole process until the voltage type rotor flux linkage

Current-type rotor magnetic pin

The deviation of (a) tends to zero, and the calculated stator resistance at this time is taken as an accurate true value. The adaptation law of the reference adaptation model is integral, i.e.:

is a vector of the current of the stator of the motor,is cross-multiplied, kr is an integral coefficient,I_rmsis the effective value of the motor current, T_sFor a sampling period, R_sThe stator resistance value, t is time.