阅读说明：本技术 一种适用于高速永磁同步电机的飞车启动方法 (Runaway starting method suitable for high-speed permanent magnet synchronous motor ) 是由 刘万斌 冯科 徐浩 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种适用于高速永磁同步电机的飞车启动方法,包括：建立估测旋转坐标系,同时对电流环实行将励磁电流和转矩电流设置为零的控制策略；对当前电流进行采样,得到估测旋转坐标系电流；以电机转子实际状态建立实际旋转坐标系,根据PI调节器调制电压得到两个坐标系之间的夹角,对此夹角求导得到当前电机转速；重复上述步骤,多次估算当前电机转速,确认辨识速度正确后切换至正常运行模式；变频器根据当前电机转速加速到目标转速,完成飞车启动过程。本方法在无速度传感器且磁链观测器失效时可准确估测永磁同步电机当前实际转速,并能快速实现平滑切换,完成高速永磁同步电机的飞车启动。(The invention discloses a runaway starting method suitable for a high-speed permanent magnet synchronous motor, which comprises the following steps of: establishing an estimated rotation coordinate system, and simultaneously executing a control strategy of setting exciting current and torque current to be zero on a current loop; sampling the current to obtain the current of an estimated rotating coordinate system; establishing an actual rotating coordinate system according to the actual state of the motor rotor, obtaining an included angle between the two coordinate systems according to the voltage modulated by the PI regulator, and obtaining the current motor rotating speed by derivation of the included angle; repeating the steps, estimating the current motor rotating speed for multiple times, and switching to a normal operation mode after confirming that the identification speed is correct; and accelerating the frequency converter to a target rotating speed according to the current rotating speed of the motor to finish the starting process of the runaway. The method can accurately estimate the current actual rotating speed of the permanent magnet synchronous motor when the speed sensor is not available and the flux linkage observer fails, can quickly realize smooth switching, and can complete the runaway starting of the high-speed permanent magnet synchronous motor.)

1. A runaway starting method suitable for a high-speed permanent magnet synchronous motor is characterized by comprising the following steps: the method comprises the following steps:

s1: establishing an estimated rotating coordinate system, wherein the included angle between the estimated rotating coordinate system and a static coordinate system is theta; exciting current reference value Id is carried out on the current loop_refAnd a torque current reference value Iq_refA control strategy set to zero;

s2: sampling current three-phase currents Ia, Ib and Ic of a stator of the motor by a current sampling module, and obtaining d-axis feedback current Id and q-axis feedback current Iq of an estimated rotating coordinate system through Clark and park transformation, wherein the d-axis feedback current Id and the q-axis feedback current Iq are shown as the following formula:

s3: the d-axis voltage Ud and the q-axis voltage Uq modulated by the current loop PI regulator are output in the form of sine waves as shown in the following equation:

wherein Ki is integral regulation coefficient, Kp is proportional regulation coefficient, and Δ Id is d-axis current given value Id_refError with d-axis feedback current Id, Δ Iq being given value of q-axis current Iq_refError with q-axis feedback current Iq;

s4: establishing an actual rotating coordinate system according to the actual state of the motor rotor, wherein an included angle theta' between the actual rotating coordinate system and the estimated rotating coordinate system is as follows:

θ′＝arctan(Ud/Uq)

s5: and obtaining the current motor rotating speed omega 'by derivation of theta':

s6: repeating the steps S1-S5, carrying out multiple estimation on the current motor rotating speed omega', confirming whether the identification speed is correct or not, and switching to a normal operation mode after confirming that the identification speed is correct;

s7: and accelerating the frequency converter to a target rotating speed according to the current rotating speed omega' of the motor to finish the starting process of the runaway.

2. The coaster starting method suitable for the high-speed permanent magnet synchronous motor according to claim 1, wherein: in step S1, the angle θ between the rotating coordinate system and the stationary coordinate system is estimated to be a fixed angle.

3. The coaster starting method suitable for the high-speed permanent magnet synchronous motor according to claim 2, wherein: in step S1, the estimated included angle θ between the rotating coordinate system and the stationary coordinate system is an angle output by the flux linkage observer.

4. The coaster starting method suitable for the high-speed permanent magnet synchronous motor according to claim 2, wherein: in step S1, the estimated included angle θ between the rotating coordinate system and the stationary coordinate system is a control angle for the frequency converter to send PWM waves to the motor.

5. The coaster starting method suitable for the high-speed permanent magnet synchronous motor according to claim 1, wherein: in step S6, when the fluctuation value of the multiple estimation results is less than 1% of the rated rotation speed, the recognition speed is determined to be correct.

6. The coaster starting method suitable for the high-speed permanent magnet synchronous motor according to claim 1, wherein: step S6, the normal operation mode is: maintaining the excitation current reference value Id_refTo zero, the torque current reference value Iq is set_refAnd switching to the output of the speed ring, and driving the motor according to the set parameters.

Technical Field

The invention relates to the technical field of motor starting, in particular to a runaway starting method suitable for a high-speed permanent magnet synchronous motor.

Background

Compared with an asynchronous motor, the traditional permanent magnet synchronous motor, especially the rare earth permanent magnet synchronous motor has the advantages of less loss, high efficiency and obvious electricity-saving effect, and has more outstanding superiority in the aspects of position control, speed control and torque control. With the cost reduction of permanent magnet materials in recent years, the permanent magnet synchronous motor is rapidly popularized, but the following problems are that: in some occasions with large inertia, the motor needs a long time to stop stably after free stop or fault stop, which causes great trouble for restarting in a short time interval. In view of such circumstances, the permanent magnet synchronous motor needs to have a runaway starting function. Different from the runaway starting of an asynchronous motor, the permanent magnet synchronous motor does not allow slip, so that the runaway starting of the permanent magnet synchronous motor can be completed only by a special strategy, and the difficulty of the runaway starting of the high-speed permanent magnet synchronous motor with low back electromotive force is greatly increased.

Disclosure of Invention

The invention provides a runaway starting method suitable for a high-speed permanent magnet synchronous motor, which aims to: on the occasion that the motor has larger inertia and under the condition of rotating speed, the current actual rotating speed of the permanent magnet synchronous motor is accurately estimated, and the restarting is realized.

The technical scheme of the invention is as follows:

a runaway starting method suitable for a high-speed permanent magnet synchronous motor comprises the following steps:

s1: establishing an estimated rotating coordinate system, wherein the included angle between the estimated rotating coordinate system and a static coordinate system is theta; exciting current reference value Id is carried out on the current loop_refAnd a torque current reference value Iq_refA control strategy set to zero;

s2: sampling current three-phase currents Ia, Ib and Ic of a stator of the motor by a current sampling module, and obtaining d-axis feedback current Id and q-axis feedback current Iq of an estimated rotating coordinate system through Clark and park transformation, wherein the d-axis feedback current Id and the q-axis feedback current Iq are shown as the following formula:

s3: the d-axis voltage Ud and the q-axis voltage Uq modulated by the current loop PI regulator are output in the form of sine waves as shown in the following equation:

wherein Ki is integral regulation coefficient, Kp is proportional regulation coefficient, and Δ Id is d-axis current given value Id_refError with d-axis feedback current Id, Δ Iq being given value of q-axis current Iq_refError with q-axis feedback current Iq;

s4: establishing an actual rotating coordinate system according to the actual state of the motor rotor, wherein an included angle theta' between the actual rotating coordinate system and the estimated rotating coordinate system is as follows:

θ′＝arctan(Ud/Uq)

s5: and obtaining the current motor rotating speed omega 'by derivation of theta':

s6: repeating the steps S1-S5, carrying out multiple estimation on the current motor rotating speed omega', confirming whether the identification speed is correct or not, and switching to a normal operation mode after confirming that the identification speed is correct;

s7: and accelerating the frequency converter to a target rotating speed according to the current rotating speed omega' of the motor to finish the starting process of the runaway.

Further, in step S1, the angle θ between the rotating coordinate system and the stationary coordinate system is estimated to be a fixed angle.

Further, the estimated angle θ between the rotating coordinate system and the stationary coordinate system in step S1 is an angle output by the flux linkage observer.

Further, in step S1, the estimated included angle θ between the rotating coordinate system and the stationary coordinate system is a control angle for the frequency converter to send the PWM wave to the motor.

Further, in step S6, when the fluctuation value of the multiple estimation results is less than 1% of the rated rotation speed, the recognition speed is determined to be correct.

Further, the normal operation mode of step S6Comprises the following steps: maintaining the excitation current reference value Id_refTo zero, the torque current reference value Iq is set_refAnd switching to the output of the speed ring, and driving the motor according to the set parameters.

Compared with the prior art, the invention has the following beneficial effects: (1) the permanent magnet synchronous motor is driven in a speed vector-free control mode, the current actual rotating speed and direction of the permanent magnet synchronous motor are accurately estimated under the condition of no speed sensor, and smooth switching can be quickly realized, so that the runaway starting of the high-speed permanent magnet synchronous motor is completed; (2) the method can still realize the tracking of the rotating speed of the motor when the flux linkage observer fails, and complete the start of the high-speed permanent magnet synchronous motor during the flying.

Drawings

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

FIG. 2 is a schematic diagram of estimating a rotational coordinate system and a stationary coordinate system;

FIG. 3 is a schematic diagram of an actual rotational coordinate system and an estimated rotational coordinate system;

fig. 4 is a schematic diagram of the modulation voltage waveform of the PI regulator.

Detailed Description

The technical scheme of the invention is explained in detail in the following with the accompanying drawings:

as shown in fig. 1, a method for starting an aircraft applicable to a high-speed permanent magnet synchronous motor, when the motor is in a high-speed running rotation state, accurately estimating the current actual rotation speed and direction of the permanent magnet synchronous motor without a speed sensor, and implementing the restart of the high-speed permanent magnet synchronous motor, includes the following steps:

s1: an estimated rotational coordinate system (d-q coordinate system) is established, the angle between the estimated rotational coordinate system and the stationary coordinate system (α - β coordinate system) being θ, as shown in fig. 2.

Optionally, the estimated included angle θ between the rotating coordinate system and the stationary coordinate system is an angle output by the flux linkage observer. The back electromotive force of the high-speed permanent magnet synchronous motor is low, and the angle output by the flux linkage observer slightly fluctuates around a certain constant value, so that the estimated rotating coordinate system is static at the moment, and theta is a fixed angle.

Optionally, the angle θ between the estimated rotating coordinate system and the stationary coordinate system is a control angle at which the frequency converter sends a PWM wave to the motor after receiving a start instruction, and θ is a fixed angle, so that the estimated rotating coordinate system is stationary at this time. The method can still realize accurate estimation of the current motor rotating speed under the condition that the flux linkage observer fails.

Exciting current reference value Id is carried out on the current loop_refAnd a torque current reference value Iq_refControl strategy set to zero.

S2: sampling current three-phase currents Ia, Ib and Ic of a stator of the motor by a current sampling module, and obtaining d-axis feedback current Id and q-axis feedback current Iq of an estimated rotating coordinate system through Clark and park transformation, wherein the d-axis feedback current Id and the q-axis feedback current Iq are shown as the following formula:

s3: as shown in fig. 4, the d-axis voltage Ud and the q-axis voltage Uq modulated by the current loop PI regulator are output in the form of sine waves as shown in the following equation:

wherein Ki is integral regulation coefficient, Kp is proportional regulation coefficient, and Δ Id is d-axis current given value Id_refError with d-axis feedback current Id, Δ Iq being given value of q-axis current Iq_refError with q-axis feedback current Iq;

s4: since the motor is still rotating at this time, an actual rotating coordinate system (d ' -q ' coordinate system) is established according to the actual state of the rotor of the motor, as shown in fig. 3 and 4, an included angle θ ' between the actual rotating coordinate system and the estimated rotating coordinate system is:

θ′＝arctan(Ud/Uq)

s5: and obtaining the current motor rotating speed omega 'by derivation of theta':

s6: repeating the steps S1-S5, carrying out multiple estimation on the current motor rotating speed omega', confirming that the identification speed is correct when the fluctuation value of the multiple estimation result is less than 1% of the rated rotating speed, and switching to a normal operation mode: maintaining the excitation current reference value Id_refTo zero, the torque current reference value Iq is set_refAnd switching to the output of the speed ring, and driving the motor according to the set parameters.

S7: and accelerating the frequency converter to a target rotating speed according to the current rotating speed omega' of the motor to finish the starting process of the runaway.

In the actual rotational coordinate system (d '-q' coordinate system), Id 'and Iq' have constant amplitudes and constant rotational speeds in a short time. As shown in fig. 3, the relationship between the estimated d-axis feedback current Id and q-axis feedback current Iq of the rotating coordinate system and the d ' axis current Id and q ' axis current Iq ' of the actual rotating coordinate system is:

therefore, Id and Iq obtained by current sampling are not static values, but periodically change along with theta ', and Id and Iq can be converted into currents Id and Iq' of an actual rotating coordinate system to reflect the actual rotating state of the motor.