阅读说明：本技术 一种电机电流随机相序的功率因数角计算方法 (Power factor angle calculation method for motor current random phase sequence ) 是由 高雅 朱秦岭 李波 李小鹏 于 2020-11-13 设计创作，主要内容包括：本发明公开了一种电机电流随机相序的功率因数角计算方法,本发明针对电机故障诊断技术研究过程中所关心的功率因数计算问题进行研究,提出了一种针对在安装多个检测电机电流传感器时,只利用一个未知相位位置的电压传感器结合多个未知相位的电流传感器检测多个电机的功率因数如何计算的方法。通过该种计算方法,可以极大程度的放宽现场安装时对相序的要求及最大化的减少电压传感器的安装数量。(The invention discloses a power factor angle calculation method of a motor current random phase sequence, which is used for researching the power factor calculation problem concerned in the motor fault diagnosis technology research process and provides a method for detecting how to calculate the power factors of a plurality of motors by only utilizing a voltage sensor at an unknown phase position and combining a plurality of current sensors at unknown phases when a plurality of current sensors for detecting the motors are installed. By the calculation method, the requirement on the phase sequence during field installation can be greatly relaxed, and the installation quantity of the voltage sensors can be reduced to the maximum extent.)

1. A power factor angle calculation method of a motor current random phase sequence is characterized by comprising the following steps:

step 1: collecting three-phase current time sequence data I of one motor_ai、I_bi、I_ciAnd one-phase voltage time-series data U_eiAnd it is not clear which phase of the voltage data is in phase with the three-phase current data;

step 2: filtering high-frequency signals, extracting the fundamental frequency waveform with the maximum energy in the three-phase current data and the one-phase voltage data acquired in the step 1 by utilizing Asin (omega t + theta), and acquiring the amplitude A of the three-phase current fundamental frequency data_a、A_b、A_cAnd amplitude B of one-phase voltage fundamental wave data_eObtaining initial phase theta of three-phase current fundamental wave data_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_e；

And step 3: for the initial phase theta of the three-phase current fundamental wave data acquired in the step 2_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_ePerforming non-negative value processing on the value of theta_a、θ_b、θ_c、θ_eAre compared with zero, respectively, theta_aTheta is greater than or equal to zero_a‘＝θ_a，θ_aLess than zero, theta_a‘＝360+θ_a；θ_bTheta is greater than or equal to zero_b‘＝θ_b，θ_bLess than zero, theta_b‘＝360+θ_b；θ_cTheta is greater than or equal to zero_c‘＝θ_c，θ_cLess than zero, theta_c‘＝360+θ_c；θ_eIs greater thanEqual to zero theta'_e＝θ_e，θ_eLess than zero, theta_e‘＝360+θ_e；

And 4, step 4: for the non-negative phase theta obtained in the step 3_a‘、θ_b‘、θ_c' ordering, find the minimum and record asWhen theta is_aAt the minimumWhen theta is_bAt the minimumWhen theta is_cAt the minimumFind the median value, recordWhen theta is_aWhen is an intermediate valueWhen theta is_bAt the minimumWhen theta is_cAt the minimumFind the maximum value asWhen theta is_aWhen is the maximum valueWhen theta is_bAt maximum timeWhen theta is_cAt maximum timeFrom the above, it can be determined which specific phase of A, B, C three phases the minimum value, the middle value and the maximum value are, and the phase a is marked as 1, the phase B is marked as 2 and the phase C is marked as 3; assigning the value of the phase corresponding to the minimum value to Z_minThe value of the phase corresponding to the intermediate value is assigned to Z_midThe value of the phase corresponding to the maximum value is assigned to Z_max；

And 5: three phases theta_a‘、θ_b‘、θ_c' subtract minimum values respectivelyTo obtain theta_a‘’、θ_b‘’、θ_c'' wherein theta_a‘’、θ_b‘’、θ_c'' must have one 0, one 120, and one 240; due to the process of step 4, it can be determined which particular phase of the three phases A, B, C is the minimum, intermediate and maximum values;

step 6: the phase theta of the voltage_e' also subtract minimum valueObtain theta_e'' determination of θ_e' with zero magnitude, theta_e'' zero or more than zero θ_e’”＝θ_e‘’，θ_e'' less than zero, theta_e‘”＝360+θ_e‘’；

And 7: will theta_a‘’、θ_b‘’、θ_c‘’、θ_e'' its theta is obtained from small to large_e'' the position value X in the arrangement order, X cannot be arranged at the first position in the sequential arrangement from small to large due to the process of step 5;

and 8: needleFor AC motors, when X is in the second position, take Z_minThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_maxThe phase is a current phase required for calculating the power factor; for an alternator, when X is in the second position, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_maxThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_minThe phase is a current phase required for calculating the power factor;

and step 9: calculating a difference value between the current phase and the voltage phase of the calculated power factor obtained in the step 8, and calculating an absolute value, wherein the angle is a power angle delta theta when the power factor is calculated;

step 10: for AC motor, the product of effective current value I and effective voltage value U is calculated and multipliedMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by sin theta to obtain the reactive power of the motor; for the AC generator, the product of the effective current value I and the effective voltage value U is calculated and multipliedMultiplying the obtained product by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productAnd multiplying by sin theta to obtain the reactive power of the motor.

Technical Field

The invention belongs to the technical field of motor fault diagnosis, and particularly relates to a power factor angle calculation method for a motor current random phase sequence.

Background

The motor accounts for more than 90% of the motor proportion in national production, and whether the motor can run efficiently as an actuating element at the bottommost layer in the production process reflects and restricts whether the motor can run safely, efficiently, excellently and with low consumption in the production and manufacturing process to a great extent. The running state of the actuating mechanism not only affects the motor, but also affects the efficient running of the whole production system, so that the data monitoring of the utilization rate and the running state in the running of the motor becomes an important content. The power factor is one of main parameters for measuring the operation efficiency of the motor, and improper power factors can influence the utilization rate of the motor, increase the reactive power output of a power grid system and destroy the proportion of reactive power and active power in the power grid. And through the calculation of the power factor of the motor, the output condition of the active power of the load of the motor and the reactive power consumption in the motor can be distinguished, and the working state of the motor is evaluated.

With the continuous advance and development of the industrialization process, enterprises pay more attention to how the equipment can operate and how the equipment can operate efficiently. The power factor of the motor is obtained through a motor fault detection and operation and maintenance system platform, and the understanding of the motor operation utilization rate becomes a main approach. In the conventional method for detecting the power factor, a voltage sensor and a current sensor are simultaneously installed on corresponding lines, and the power factor is obtained by calculating a phase difference. This method has the disadvantages of requiring more sensors and installation in the event that the voltage must be shut down, making both early installation and later replacement difficult.

Disclosure of Invention

The invention relates to a power factor angle calculation method for a random phase sequence of motor current, which solves the problems that a plurality of voltage sensors are needed, the installation phase sequences of the sensors correspond to the corresponding current sensors one by one, and the installation and the replacement are difficult in the prior art.

In order to solve the problems, the technical scheme of the invention is as follows:

a power factor angle calculation method of a motor current random phase sequence is characterized by comprising the following steps:

step 1: collecting three-phase current time sequence data I of one motor_ai、I_bi、I_ciAnd one-phase voltage time-series data U_eiAnd it is not clear which phase of the voltage data is in phase with the three-phase current data;

step 2: filtering high frequency signal, extracting by Asin (omega t + theta) in step 1The amplitude A of the three-phase current fundamental wave data is obtained by collecting the three-phase current data and the fundamental frequency waveform with the maximum energy in the one-phase voltage data_a、A_b、A_cAnd amplitude B of one-phase voltage fundamental wave data_eObtaining initial phase theta of three-phase current fundamental wave data_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_e；

And step 3: for the initial phase theta of the three-phase current fundamental wave data acquired in the step 2_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_ePerforming non-negative value processing on the value of theta_a、θ_b、θ_c、θ_eAre compared with zero, respectively, theta_aTheta is greater than or equal to zero_a‘＝θ_a，θ_aLess than zero, theta_a‘＝360+θ_a；θ_bTheta is greater than or equal to zero_b‘＝θ_b，θ_bLess than zero, theta_b‘＝360+θ_b；θ_cTheta is greater than or equal to zero_c‘＝θ_c，θ_cLess than zero, theta_c‘＝360+θ_c；θ_eTheta is greater than or equal to zero_e‘＝θ_e，θ_eLess than zero, theta_e‘＝360+θ_e；

And 4, step 4: for the non-negative phase theta obtained in the step 3_a‘、θ_b‘、θ_c'sorting, finding the minimum value is recorded as theta'_minWhen theta is_a'minimum hour θ'_min＝θ_a', when theta_b'minimum hour θ'_min＝θ_b', when theta_c'minimum hour θ'_min＝θ_c'; find an intermediate value, record as θ'_midWhen theta is_a'is intermediate value of theta'_mid＝θ_a', when theta_b'minimum hour θ'_mid＝θ_b', when theta_c'minimum hour θ'_mid＝θ_c'; find the maximum value of theta'_maxWhen theta is_a'is at maximum value θ'_max＝θ_a', when theta_b'at maximum time of θ'_max＝θ_b', when theta_c'at maximum time of θ'_max＝θ_c'; from the above, it can be determined which specific phase of A, B, C three phases the minimum value, the middle value and the maximum value are, and the phase a is marked as 1, the phase B is marked as 2 and the phase C is marked as 3; assigning the value of the phase corresponding to the minimum value to Z_minThe value of the phase corresponding to the intermediate value is assigned to Z_midThe value of the phase corresponding to the maximum value is assigned to Z_max；

And 5: three phases theta_a‘、θ_b‘、θ_c' all minus minimum values θ ' respectively '_minTo obtain theta_a‘’、θ_b‘’、θ_c'' wherein theta_a‘’、θ_b‘’、θ_c'' must have one 0, one 120, and one 240; due to the process of step 4, it can be determined which particular phase of the three phases A, B, C is the minimum, intermediate and maximum values;

step 6: the phase theta of the voltage_e' minimum value θ ' is subtracted from the same '_minObtaining theta_e'' determination of θ_e' with zero magnitude, theta_e'' zero or more than zero θ_e‘”＝θ_e‘’，θ_e'' less than zero, theta_e‘”＝360+θ_e‘’；

And 7: will theta_a‘’、θ_b‘’、θ_c‘’、θ_e'obtaining theta of the' according to the sequence from small to large_e'' the position value X in the arrangement order, X cannot be arranged at the first position in the sequential arrangement from small to large due to the process of step 5;

and 8: for AC motors, when X is in the second position, take Z_minThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_maxThe phase is a current phase required for calculating the power factor; for alternators when X is in the second positionWhen, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_maxThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_minThe phase is a current phase required for calculating the power factor;

and step 9: calculating a difference value between the current phase and the voltage phase of the calculated power factor obtained in the step 8, and calculating an absolute value, wherein the angle is a power angle delta theta when the power factor is calculated;

step 10: for AC motor, the product of effective current value I and effective voltage value U is calculated and multipliedMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by sin theta to obtain the reactive power of the motor; for the AC generator, the product of the effective current value I and the effective voltage value U is calculated and multipliedMultiplying the obtained product by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productAnd multiplying by sin theta to obtain the reactive power of the motor.

Compared with the prior art, the invention has the beneficial effects that:

the invention aims at the power factor calculation problem concerned in the motor fault diagnosis technology research process, and provides a method for detecting how to calculate the power factors of a plurality of motors by only utilizing a voltage sensor at an unknown phase position and combining a plurality of current sensors at unknown phases when a plurality of current sensors for detecting the motors are installed.

Drawings

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

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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.

The method of the invention is based on the working principle of an alternating current motor and an alternating current generator, analyzes the phase sequence and the phase relationship of three-phase current and voltage of the motor according to the vector relationship among parameters in the working process of the motor, analyzes the power factor of the motor or the motors by utilizing the one-phase voltage and the three-phase current data which are acquired by the motor or the motors and are not divided into the phase sequence, and solves the problems that the invention needs to solve because the acquired voltage and current data are not corresponding to the phase sequence and the phase sequence has randomness, how to analyze the phase sequence of the three-phase current of the motor through the vector relationship among the parameters of the conventional alternating current generator and the alternating current motor, and how to calculate the power factor of the motor by combining the acquired phase voltage of the one phase with the.

The present invention is applicable to an alternating current motor for which the phase of each phase of the voltage leads the phase of the current, and an alternating current generator for which the phase of each phase of the voltage lags the phase of the current, and for which the phase difference between each phase of the voltage and the current does not exceed 90 degrees.

The specific content of the method for calculating the power factor angle of the voltage and current random phase sequence of the alternating current motor is shown in fig. 1, the embodiment takes one motor as an example, and the scheme and the steps are also suitable for a plurality of motors.

The method of the embodiment comprises the following steps:

step 1: one motor is collectedThree-phase current time-series data I_ai、I_bi、I_ciAnd one-phase voltage time-series data U_eiAnd it is not clear which phase of the voltage data is in phase with the three-phase current data;

step 2: filtering the high-frequency signal, extracting the fundamental frequency waveform with the maximum energy in the three-phase current data and the one-phase voltage data acquired in the step 1 by utilizing Asin (omega t + theta), and acquiring the amplitude A of the three-phase current fundamental frequency data_a、A_b、A_cAnd amplitude B of one-phase voltage fundamental wave data_eObtaining initial phase theta of three-phase current fundamental wave data_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_e；

And step 3: sequencing is started by utilizing the principle that the phases of three-phase currents in the alternating current motor are 120 degrees different from each other; since the three-phase current fundamental wave data is a periodic signal and the phase thereof also changes periodically between 0 ° and 360 °, the initial phase θ of the three-phase current fundamental wave data acquired in step 2 is adjusted by using the characteristics of the periodic change_a、θ_b、θ_cAnd initial phase theta of one-phase voltage fundamental wave data_ePerforming non-negative value processing on the value of theta_a、θ_b、θ_c、θ_eAre compared with zero, respectively, theta_aTheta is greater than or equal to zero_a‘＝θ_a，θ_aLess than zero, theta_a‘＝360+θ_a；θ_bTheta is greater than or equal to zero_b‘＝θ_b，θ_bLess than zero, theta_b‘＝360+θ_b；θ_cTheta is greater than or equal to zero_c‘＝θ_c，θ_cLess than zero, theta_c‘＝360+θ_c；θ_eTheta is greater than or equal to zero_e‘＝θ_e，θ_eLess than zero, theta_e‘＝360+θ_e；

And 4, step 4: for the non-negative phase theta obtained in the step 3_a‘、θ_b‘、θ_c'sorting, finding the minimum value is recorded as theta'_minWhen theta is_a'minimum hour θ'_min＝θ_a', when theta_b'minimum hour θ'_min＝θ_b', when theta_c'minimum hour θ'_min＝θ_c(ii) a Find an intermediate value, record as θ'_midWhen theta is_a'is intermediate value of theta'_mid＝θ_a', when theta_b'minimum hour θ'_mid＝θ_b', when theta_c'minimum hour θ'_mid＝θ_c'; find the maximum value of theta'_maxWhen theta is_a'is at maximum value θ'_max＝θ_a', when theta_b'at maximum time of θ'_max＝θ_b', when theta_c'at maximum time of θ'_max＝θ_c'; from the above, it can be determined which specific phase of A, B, C three phases the minimum value, the middle value and the maximum value are, and the phase a is marked as 1, the phase B is marked as 2 and the phase C is marked as 3; assigning the value of the phase corresponding to the minimum value to Z_minThe value of the phase corresponding to the intermediate value is assigned to Z_midThe value of the phase corresponding to the maximum value is assigned to Z_max；

And 5: three phases theta_a‘、θ_b‘、θ_c' all minus minimum values θ ' respectively '_minTo obtain theta_a‘’、θ_b‘’、θ_c'' wherein theta_a‘’、θ_b‘’、θ_c'' must have one 0, one 120, and one 240; due to the process of step 4, it can be determined which particular phase of the three phases A, B, C is the minimum, intermediate and maximum values;

step 6: the phase theta of the voltage_e' minimum value θ ' is subtracted from the same '_minObtaining theta_e'' determination of θ_e' with zero magnitude, theta_e'' zero or more than zero θ_e‘”＝θ_e‘’，θ_e'' less than zero, theta_e‘”＝360+θ_e‘’；

And 7: will theta_a‘’、θ_b‘’、θ_c‘’、θ_e'' its theta is obtained from small to large_e'' atThe position value X in the ranking order, X cannot be ranked first in the ranking order from small to large due to the process of step 5;

and 8: for AC motors, when X is in the second position, take Z_minThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_maxThe phase is a current phase required for calculating the power factor; for an alternator, when X is in the second position, take Z_midThe phase is a current phase required for calculating the power factor; when X is arranged at the third position, take Z_maxThe phase is a current phase required for calculating the power factor; when X is arranged at the fourth position, take Z_minThe phase is a current phase required for calculating the power factor;

and step 9: calculating a difference value between the current phase and the voltage phase of the calculated power factor obtained in the step 8, and calculating an absolute value, wherein the angle is a power angle delta theta when the power factor is calculated;

step 10: for AC motor, the product of effective current value I and effective voltage value U is calculated and multipliedMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productMultiplying the efficiency eta by the efficiency eta, and multiplying the efficiency eta by sin theta to obtain the reactive power of the motor; for the AC generator, the product of the effective current value I and the effective voltage value U is calculated and multipliedMultiplying the obtained product by cos theta to obtain the active power of the motor; calculating the product of the effective value of current I and the effective value of voltage U, and multiplying the productAnd multiplying by sin theta to obtain the reactive power of the motor.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. Any partial modification or replacement within the technical scope of the present disclosure by a person skilled in the art should be included in the scope of the present disclosure.