阅读说明：本技术 一种伺服电机极对数检测方法、驱动器及系统 (Servo motor pole pair number detection method, driver and system ) 是由 王岩 谭章德 区均灌 许凤霞 王长恺 刘亚祥 夏培培 于 2019-08-21 设计创作，主要内容包括：本发明提供了一种伺服电机极对数检测方法、驱动器及系统,方法为通过获得被测电机转动后的编码器脉冲数pulse2与初始的编码器脉冲数pulse1比较,计算出脉冲差值△pulse,然后根据公式计算得出电机极对数p=(θ/360)*2<Sup>n</Sup>/△pulse；驱动器包括数值设置模块、角度设置生成模块、IPARK模块、SVPWM模块、三相逆变器、编码器位置差计算模块和获取绝对值编码器类型最大计数值模块；本发明克服了现有技术中检测电机极对数存在的偏差问题,可以得到准确的电机极对数,而且该方法不需要人工操作。(The invention provides a servo motor pole pair number detection method, a servo motor pole pair number detection driver and a servo motor pole pair number detection system, wherein the method comprises the steps of comparing an encoder pulse2 obtained after a detected motor rotates with an initial encoder pulse1, calculating a pulse difference value delta pulse, and calculating a motor pole pair number p = (theta/360) × 2 according to a formula n /. DELTA.pulse; the driver comprises a numerical value setting module, an angle setting generation module, an IPARK module, an SVPWM module, a three-phase inverter, an encoder position difference calculation module and an absolute value acquisition encoder type maximum count value module; the invention overcomes the deviation problem existing in the detection of the number of the pole pairs of the motor in the prior art, can obtain the accurate number of the pole pairs of the motor, and does not need manual operation.)

1. A servo motor pole pair number detection method is characterized in that a pulse difference value delta pulse is calculated by comparing an encoder pulse2 obtained after a detected motor rotates with an initial encoder pulse1, and then a motor pole pair number p = (theta/360) × 2 is calculated according to a formulaⁿWhere p denotes the number of pole pairs of the motor, θ denotes the electrical angle, and n denotes the number of encoder bits.

2. The servo motor pole pair number detection method as set forth in claim 1, wherein: comparing the encoder pulse number pulse2 after the motor rotates with the initial encoder pulse number pulse1 specifically is: if pulse2<pulse1, the pulse difference after the motor rotates is delta pulse = 2ⁿ- pulse1+ pulse2。

3. The servo motor pole pair number detection method as set forth in claim 1, wherein: comparing the encoder pulse number pulse2 after the motor rotates with the initial encoder pulse number pulse1 specifically is: if pulse2> pulse1, the pulse difference Δ pulse after the motor rotation = pulse2-pulse 1.

4. The servo motor pole pair number detection method as set forth in claim 1, wherein: the method comprises the following specific steps:

s1, acquiring initial encoder impulse 1 of the servo motor;

s2, the servo driver adopts voltage open loop to control the servo motor to rotate;

s3, reading the pulse number pulse2 of the encoder when the servo motor stops rotating;

s4, comparing the pulse1 with the pulse2, and calculating a pulse difference value delta pulse;

s5, using the calculated pulseThe impulse value is calculated by the formula p = (theta/360) × 2ⁿAnd calculating the pole pair number P of the motor by delta pulse.

5. The servo motor pole pair number detection method as set forth in claim 4, wherein: the step S2 is specifically: the numerical values of Ud and Uq are set by using a key, the electrical angle theta reaches a value between 360 degrees from 0 degree according to a certain frequency, then the value is kept unchanged, and a servo motor rotates, wherein the Ud and the Uq are set voltage values.

6. The servo motor pole pair number detection method as set forth in claim 4, wherein: the step S2 is specifically: the numerical values of Ud and Uq are set by using the keys, the electrical angle theta reaches a value between-360 degrees from 0 degree according to a certain frequency, and then the servo motor rotates while the electrical angle theta is kept unchanged.

7. The servo motor pole pair number detection method as claimed in claim 5 or 6, wherein: the step S3 is specifically: when the electrical angle θ is kept constant, the motor stops rotating, is fixed at the set electrical angle position, and reads the encoder pulse number pulse2 at this time.

8. The servo motor pole pair number detection method as claimed in claim 5 or 6, wherein: the servo driver adopts voltage open loop opening control, inputs numerical values of Ud and Uq, utilizes IPARK to realize conversion from Ud and Uq to Ualpha and Ubeta, and the SVPWN module outputs six paths of PWM waves to control the three-phase inverter to enable the servo motor to rotate.

9. The servo motor pole pair number detection method as claimed in claim 8, wherein: the obtained Ualpha and the obtained Ubeta are used for an SVPWM algorithm, and the relationship corresponding to the following formula exists among Ud, Uq and theta:

Uα = Ud*cosθ–Uq*sinθ

Uβ = Ud*sinθ + Uq*cosθ。

10. the servo motor pole pair number detection method as set forth in claim 1, wherein: and finally, displaying the calculated number of the pole pairs of the motor through a pole pair number display module.

11. The servo motor pole pair number detection method as claimed in claim 7, wherein: after the electrical angle theta is set, the current waveform is a sine wave before the servo motor reaches the set electrical angle theta, the period is the reciprocal of the change frequency of the electrical angle theta, and the current waveform is kept unchanged after the electrical angle theta is reached.

12. A drive having a function of detecting the number of pole pairs of a servo motor, the method of detecting the number of pole pairs of a servo motor according to any one of claims 1 to 11 being implemented when the function is operated.

13. The driver of claim 12, comprising a value setting module, an angle setting generation module, an IPARK module, an SVPWM module, a three-phase inverter, an encoder position difference calculation module, and an absolute value encoder type maximum count value acquisition module, wherein the value setting module is configured to input voltage values Ud and Uq, the angle setting generation module is configured to set and generate an electrical angle θ, the conversion from a dq coordinate system of the IPARK module to an α β coordinate system is implemented as the conversion from the Ud coordinate system to the Uq coordinate system to the U α coordinate system, the SVPWM module outputs six PWM waves to control the three-phase inverter, the three-phase inverter outputs signals to control the rotation of the servo motor, the encoder position difference calculation module is configured to calculate a pulse difference value counted by the encoder when the servo motor is started to stopped, and the absolute value encoder type maximum count value acquisition module can automatically acquire an encoder type of the motor to be measured and a maximum count value of the encoder when the driver is powered on.

14. The driver of claim 13, further comprising a log display module in the form of a digital tube or a liquid crystal screen.

15. A system comprising a servo motor and a driver for driving the servo motor to rotate, wherein the driver is operative to implement the servo motor pole pair number detection method as claimed in any one of claims 1 to 11.

Technical Field

The invention relates to the technical field of industrial automation control, in particular to a servo motor pole pair number detection method, a servo motor pole pair number driver and a servo motor pole pair number system.

Background

The number of pole pairs of the motor plays a crucial role in controlling the servo system, and if the number of pole pairs is set incorrectly, the driver cannot work normally. According to the traditional motor pole pair number detection method, according to the principle that the counter electromotive force change period number corresponding to one rotation of a motor rotor is twice of the motor pole pair number, a three-phase armature of a motor is subjected to star short circuit through a resistor, then the motor rotor is manually rotated, and meanwhile an oscilloscope is used for measuring the counter electromotive force of the armature and a center point, and the method is complicated. For example, chinese patent No. cn201710807927.x, a method and system for detecting pole pair number of permanent magnet synchronous motor using formula p =60 × f/n_fbCalculating the number of pole pairs of the motor, where n_fbThe motor is at a constant speed, and after the motor is started, the motor starts to accelerate and finally operates at a stable speed, but the method for obtaining the stable speed by setting the preset operation speed obtaining time in the patent has deviation.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a servo motor pole pair number detection method, a driver and a system.

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

a servo motor pole pair number detection method includes the steps that an encoder pulse number pulse2 obtained after rotation of a detected motor is compared with an initial encoder pulse number pulse1, a pulse difference value delta pulse is calculated, and then a motor pole pair number p = (theta/360) × 2 is calculated according to a formulaⁿWhere p denotes the number of pole pairs of the motor, θ denotes the electrical angle, and n denotes the number of encoder bits.

Further, comparing the encoder pulse number pulse2 after the motor rotates with the initial encoder pulse number pulse1 specifically is: if pulse2<pulse1, the pulse difference after the motor rotates is delta pulse = 2ⁿ- pulse1+ pulse2。

Further, comparing the encoder pulse number pulse2 after the motor rotates with the initial encoder pulse number pulse1 specifically is: if pulse2> pulse1, the pulse difference Δ pulse after the motor rotation = pulse2-pulse 1.

Further, the method comprises the following specific steps:

s1, acquiring initial encoder impulse 1 of the servo motor;

s2, the servo driver adopts voltage open loop to control the servo motor to rotate;

s3, reading the pulse number pulse2 of the encoder when the servo motor stops rotating;

s4, comparing the pulse1 with the pulse2, and calculating a pulse difference value delta pulse;

and S5, calculating the number of pole pairs P of the motor by using the calculated pulse difference value through a formula P = (theta/360) × 2 n/delta pulse.

Further, the step S2 is specifically: the numerical values of Ud and Uq are set by using the keys, the electrical angle theta reaches a value between 360 degrees from 0 degree according to a certain frequency, then the value is kept unchanged, the servo motor rotates, starting voltage can be input to rotate aiming at motors with different powers, and the applicability is strong. And Uq is the set voltage value. Because the rotational inertia of the motors with different powers is different, the set Ud and Uq values enable the motors to overcome the rotational inertia of the motors, and thus the requirement of carrying out pole pair number detection on the motors with different powers can be met.

Further, the step S2 is specifically: the numerical values of Ud and Uq are set by using the keys, the electrical angle theta reaches a value between-360 degrees from 0 degree according to a certain frequency, and then the servo motor rotates while the electrical angle theta is kept unchanged.

Further, the step S3 is specifically: when the electrical angle θ is kept constant, the motor stops rotating, is fixed at the set electrical angle position, and reads the encoder pulse number pulse2 at this time.

Furthermore, the servo driver adopts voltage open loop opening control, the numerical values of Ud and Uq are input, the conversion from Ud and Uq to Ualpha and Ubeta is realized by utilizing IPARK, the SVPWN module outputs six paths of PWM waves to control the three-phase inverter, and the servo motor rotates.

Further, the obtained U α and U β are used in an SVPWM algorithm, and the relationship between Ud, Uq and θ has the following formula:

Uα = Ud*cosθ–Uq*sinθ

Uβ = Ud*sinθ + Uq*cosθ。

and further, the number of pole pairs of the motor which is finally calculated is displayed through a pole pair number display module.

Further, after the electrical angle θ is set, the current waveform is a sine wave before the servo motor reaches the set electrical angle θ, the period is the reciprocal of the change frequency of the electrical angle θ, and the current waveform remains unchanged after the electrical angle θ is reached.

A driver has a function of detecting the number of pole pairs of a servo motor, and the method for detecting the number of pole pairs of the servo motor is realized when the detection function is operated.

Further, set up the module including numerical value, angle and generate module, IPARK module, SVPWM module, three-phase inverter, encoder position difference calculation module and obtain the biggest count value module of absolute value encoder type, the numerical value sets up the module and is used for input voltage value Ud, Uq, the angle sets up the module and is used for setting up and generating electric angle theta, the conversion of IPARK module dq coordinate system to alpha beta coordinate system realizes the Ud promptly, can input starting voltage and rotate to the motor of different powers, and the suitability is strong. The conversion from the dq coordinate system to the alpha-beta coordinate system is to match with an SVPWM algorithm, the required input of SVPWM is the voltage components of alpha and beta axes, the SVPWM module outputs six paths of PWM waves to control a three-phase inverter, the three-phase inverter outputs signals to control the rotation of a servo motor, an encoder position difference calculation module is used for calculating the pulse difference value counted by an encoder when the servo motor is started to stopped, and the absolute value encoder type maximum count value acquisition module can automatically acquire the encoder type of the motor to be detected and the maximum count value of the encoder when a driver is powered on.

Furthermore, the display device also comprises a logarithm of poles display module, wherein the logarithm of poles display module is in a specific form of a nixie tube or a liquid crystal screen.

A system comprises a servo motor and a driver, wherein the driver drives the servo motor to rotate, and the driver realizes the servo motor pole pair number detection method in any one of the above modes when in operation.

The servo motor pole pair number detection method provided by the invention has the beneficial effects that: the method has the advantages that the problem of deviation existing in the detection of the number of the pole pairs of the motor in the prior art is solved, the accurate number of the pole pairs of the motor can be obtained, manual operation is not needed, the number of the pulses of the rotation of the motor can be obtained only by inputting the starting voltage of the motor, the pulse difference value is calculated, and finally the number of the pole pairs of the motor is calculated by utilizing the pulse difference value, so that the method is convenient, rapid and high in accuracy, and the detection efficiency can be effectively improved; in addition, different starting voltages can be input to rotate aiming at motors with different powers, and the applicability is strong.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention;

fig. 2 is a schematic diagram of the change process of the motor phase current during pole pair number detection.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying 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 obtained by a person skilled in the art without making any inventive step are within the scope of the present invention.