阅读说明：本技术 一种双余度无刷直流电机控制系统可靠度计算方法 (Reliability calculation method for control system of dual-redundancy brushless direct current motor ) 是由 付朝阳 刘兴邦 刘铮 孙平 于 2021-06-29 设计创作，主要内容包括：本发明涉及一种双余度无刷直流电机控制系统可靠度计算方法,属于电机技术领域。首先确定双余度无刷直流电机控制系统中在运行过程中容易发生故障的各个零件,并根据各个零件之间的联结方式建立双余度无刷直流电机控制系统可靠度模型。通常双余度无刷直流电机控制系统容易发生的故障的零件分别为：定子绕组、永磁体、霍尔传感器、控制芯片、功率管和轴承。通过分析影响各个零件发生故障的影响因素,单独计算各个零件的故障率和可靠度,最后通过可靠度模型计算双余度无刷直流电机控制系统总的可靠度。本发明实现了对电机控制系统可靠度的精准计算,提升了双余度无刷直流电机控制系统寿命测试的工作效益。(The invention relates to a method for calculating the reliability of a control system of a dual-redundancy brushless direct current motor, and belongs to the technical field of motors. Firstly, determining each part which is easy to have faults in the operation process in the dual-redundancy brushless direct current motor control system, and establishing a reliability model of the dual-redundancy brushless direct current motor control system according to the connection mode among the parts. The parts of the common dual-redundancy brushless direct current motor control system which are easy to malfunction are respectively: stator winding, permanent magnet, hall sensor, control chip, power tube and bearing. And finally, calculating the total reliability of the dual-redundancy brushless direct current motor control system through a reliability model. The invention realizes the accurate calculation of the reliability of the motor control system and improves the working benefit of the service life test of the dual-redundancy brushless direct current motor control system.)

1. A reliability calculation method for a dual-redundancy brushless direct current motor control system is characterized in that main faults of the dual-redundancy brushless direct current motor control system are divided into winding faults, permanent magnet faults, Hall sensor faults, control chip faults, power tube faults and bearing faults; calculating the failure rate lambda of each element in turn_p(ii) a According to the connection mode of each element in the dual-redundancy brushless direct current motor control system and the using amount of each element in the dual-redundancy brushless direct current motor control system, the service life of each element is considered to be subjected to single-parameter exponential distribution, and therefore the reliability R of each element can be obtained_i(ii) a The reliability R of each element_iThe multiplication yields the total reliability.

2. The method according to claim 1, wherein the failure rate calculation formulas of the winding, the permanent magnet, the hall sensor, the control chip, the power tube and the bearing are as follows:

(1) the failure rate of the stator winding is as follows: lambda [ alpha ]_p11＝λ_b1π_E1π_Q1π_K1π_C1

Wherein λ is_b1Is the fundamental failure rate of the winding coil, pi_E1Is an environmental coefficient, pi_Q1Is a mass coefficient of pi_K1Is a coefficient of species, pi_C1Is a structural coefficient;

(2) the failure rate of the permanent magnet is as follows: lambda [ alpha ]_P2＝λ_b2π_E2π_Q2

Wherein λ is_b2Is the basic failure rate of the permanent magnet, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient;

(3) failure rate of a single hall sensor: lambda [ alpha ]_P3＝λ_b3π_E3π_Q3π_A3π_K3π_C3π_r3

Wherein λ is_b2To a basic failure rate, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient of pi_K2Is a coefficient of species, pi_C2Is a structural coefficient;

(4) the failure rate of the control chip is as follows: lambda [ alpha ]_P4＝π_Q4[C₁π_T4π_V4+(C₂+C_3.)π_E4)]π_L4

Wherein, pi_E4Is an environmental coefficient, pi_Q4Is a mass coefficient of pi_L4To the maturation factor,. pi_T4Is the temperature stress coefficient, pi_V4Coefficient of voltage stress, C₁And C₂For complex failure rate of circuit, C_3.For package complexity failure rate;

(5) the failure rate calculation formula of a single power tube in a set of control circuit is as follows: lambda [ alpha ]_P51＝λ_b5π_E5π_Q5π_A5π_S52π_r5π_C5Wherein, pi_E4Is an environmental coefficient, pi_Q4Is a mass coefficient of pi_L4To the maturation factor,. pi_T4Is the temperature stress coefficient, pi_V4Coefficient of voltage stress, C₁And C₂For complex failure rate of circuit, C_3.For package complexity failure rate;

(6) failure rate lambda of single bearing_z(t) is:

wherein P is the equivalent dynamic load borne by the rolling bearing, and n is the rotating speed of the bearing; f. of_QTemperature coefficient introduced to characterize basic dynamic load rating, f_pTo characterize the load factor induced by vibration or shock in operation; m and epsilon are shape parameters; c is the rated dynamic load of the rolling bearing, and the value of the rated dynamic load is related to the temperature and parameters of the bearing.

3. The method according to claim 2, wherein the values of m of different bearings are as follows: the ball bearing m is 10/9, the cylindrical roller bearing m is 3/2, and the tapered roller bearing m is 4/3.

4. The method according to claim 2, wherein the values of epsilon for different bearings are as follows: the ball bearing epsilon is 3, and the roller bearing epsilon is 10/3.

5. The method according to claim 1, wherein the reliability R of each element is calculated based on the reliability of each element_iThe calculation formula is as follows:

(1) two sets of windings in total in the dual-redundancy brushless direct current motor control system adopt a parallel connection mode, and then the winding reliability is as follows:

(2) the reliability of the permanent magnet in the dual-redundancy brushless direct current motor control system is as follows:

(3) three Hall sensors are connected in series in the control system, and the reliability of the sensors is as follows:

(4) the dual-redundancy brushless direct current motor control system has a control chip, and the reliability of the chip is as follows:

(5) according to the method, the number of power tubes in a single set of control circuit of a dual-redundancy motor control system is 6, and the two sets of control circuits are connected in parallel, so that the reliability of all the power tubes is determined as follows:

(6) the number of the bearings in the control system is 2, and the connection mode is series connection; the total bearing reliability after t hours of operation is:

Technical Field

The invention belongs to the field of motor control, and particularly relates to a method for calculating the reliability of a dual-redundancy brushless direct current motor control system.

Background

The motor reliability requirement in aerospace is very high, and the operation reliability of the motor adopting double redundancy is greatly improved compared with that of a single motor. The main elements affecting the reliability of the dual-redundancy brushless direct current motor control system under the normal state are as follows: the device comprises a winding, a permanent magnet, a Hall sensor, a control chip, a power tube and a bearing. The faults of the motor windings comprise open-circuit faults and short-circuit faults, and the dual-redundancy motor improves the reliability of the motor by adopting a mode that two sets of windings share one motor rotor. The Hall sensor in the dual-redundancy motor plays a role in detecting the position of the rotor, and the Hall sensor as a semiconductor device is easy to have one or two faults in complex and severe working environments such as high and low temperature, strong impact, strong vibration and the like, so that the distortion of three-phase current is caused. The faults of the power tube include short-circuit faults and open-circuit faults. The failure of any element in the motor can cause the motor to be incapable of working normally, so that the reliability of each element of the dual-redundancy brushless direct current motor control system is calculated, the reliability level of operation of each part of the motor can be actively ensured, and the aim of improving the working quality of the whole motor is fulfilled.

At present, the reliability of a dual-redundancy brushless direct current motor control system is often obtained by a life test experiment method, and the method needs tedious and long-time experiment verification and cannot meet the requirements on rapidity and instantaneity of reliability measurement.

Disclosure of Invention

Technical problem to be solved

In order to solve the problems of long time, high cost and the like of the prior art for testing the service life of the dual-redundancy brushless direct current motor control system, the invention provides a reliability calculation method of the dual-redundancy brushless direct current motor control system, the reliability of the dual-redundancy brushless direct current motor control system can be obtained through formula calculation, and the complicated and long-time reliability measurement experiment of the dual-redundancy brushless direct current motor control system is avoided.

Technical scheme

A reliability calculation method for a dual-redundancy brushless direct current motor control system is characterized in that main faults of the dual-redundancy brushless direct current motor control system are divided into winding faults, permanent magnet faults and Hall sensorsFaults, control chip faults, power tube faults and bearing faults; calculating the failure rate lambda of each element in turn_p(ii) a According to the connection mode of each element in the dual-redundancy brushless direct current motor control system and the using amount of each element in the dual-redundancy brushless direct current motor control system, the service life of each element is considered to be subjected to single-parameter exponential distribution, and therefore the reliability R of each element can be obtained_i(ii) a The reliability R of each element_iThe multiplication yields the total reliability.

The structure of the dual-redundancy brushless direct current motor control system is different from that of other motor control systems, and the dual-redundancy brushless direct current motor control system mainly comprises a permanent magnet, an iron core, a rotating shaft, a bearing, a stator winding, a power tube, a Hall sensor and a chip. In actual operation, the most prone parts of the control system to failure are the stator windings, the permanent magnets, the hall sensors, the power tubes, the control chip and the bearings. The service life of the current motor is mainly obtained by experimental measurement, namely the service life of the motor is measured when the motor runs to a fault. The method is to verify the whole motor through experiments, and does not consider each part. The method provided by the invention calculates each part which is most prone to failure, and finally obtains the total reliability of the dual-redundancy brushless direct current motor control system.

The failure rate calculation formulas of the winding, the permanent magnet, the Hall sensor, the control chip, the power tube and the bearing are as follows:

(1) the failure rate of the stator winding is as follows: lambda [ alpha ]_p11＝λ_b1π_E1π_Q1π_K1π_C1

Wherein λ is_b1Is the fundamental failure rate of the winding coil, pi_E1Is an environmental coefficient, pi_Q1Is a mass coefficient of pi_K1Is a coefficient of species, pi_C1Is a structural coefficient;

(2) the failure rate of the permanent magnet is as follows: lambda [ alpha ]_P2＝λ_b2π_E2π_Q2

Wherein λ is_b2Is the basic failure rate of the permanent magnet, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient;

(3) failure rate of a single hall sensor: lambda [ alpha ]_P3＝λ_b3π_E3π_Q3π_A3π_K3π_C3π_r3

Wherein λ is_b2To a basic failure rate, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient of pi_K2Is a coefficient of species, pi_C2Is a structural coefficient;

(4) the failure rate of the control chip is as follows: lambda [ alpha ]_P4＝π_Q4[C₁π_T4π_V4+(C₂+C₃.)π_E4)]π_L4

Wherein, pi_E4Is an environmental coefficient, pi_Q4Is a mass coefficient of pi_L4To the maturation factor,. pi_T4Is the temperature stress coefficient, pi_V4Coefficient of voltage stress, C₁And C₂For complex failure rate of circuit, C₃Package complexity failure rate;

(5) the failure rate calculation formula of a single power tube in a set of control circuit is as follows: lambda [ alpha ]_P51＝λ_b5π_E5π_Q5π_A5π_S52π_r5π_C5

Wherein, pi_E4Is an environmental coefficient, pi_Q4Is a mass coefficient of pi_L4To the maturation factor,. pi_T4Is the temperature stress coefficient, pi_V4Coefficient of voltage stress, C₁And C₂For complex failure rate of circuit, C₃Package complexity failure rate;

(6) failure rate lambda of single bearing_z(t) is:

wherein P is the equivalent dynamic load borne by the rolling bearing, and n is the rotating speed of the bearing; f. of_QTemperature coefficient introduced to characterize basic dynamic load rating, f_pTo characterize the load factor induced by vibration or shock in operation; m and epsilon are shape parameters; c is the rated dynamic load of the rolling bearingThe values are related to the temperature and parameters of the bearing.

The values of m of different bearings are as follows: the ball bearing m is 10/9, the cylindrical roller bearing m is 3/2, and the tapered roller bearing m is 4/3.

The values of epsilon of different bearings are as follows: the ball bearing epsilon is 3, and the roller bearing epsilon is 10/3.

Reliability R of each element_iThe calculation formula is as follows:

(1) two sets of windings in total in the dual-redundancy brushless direct current motor control system adopt a parallel connection mode, and then the winding reliability is as follows:

(2) the reliability of the permanent magnet in the dual-redundancy brushless direct current motor control system is as follows:

(3) three Hall sensors are connected in series in the control system, and the reliability of the sensors is as follows:

(4) the dual-redundancy brushless direct current motor control system has a control chip, and the reliability of the chip is as follows:

(5) according to the method, the number of power tubes in a single set of control circuit of a dual-redundancy motor control system is 6, and the two sets of control circuits are connected in parallel, so that the reliability of all the power tubes is determined as follows:

(6) the number of the bearings in the control system is 2, and the connection mode is series connection; the total bearing reliability after t hours of operation is:

advantageous effects

The invention provides a method for calculating the reliability level of a dual-redundancy brushless direct current motor control system, which obtains accurate motor reliability by comprehensively considering the failure rate of each element of a motor under different working occasions and working time. Compared with the motor service life testing work, the method provided by the invention can rapidly and accurately obtain the reliability of the motor, greatly shortens the service life testing time and reduces the service life testing cost.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

Fig. 1 is a reliability model of a dual redundancy brushless dc motor control system.

Fig. 2 is a topology of a dual redundancy brushless dc motor control system.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The structure of the dual-redundancy brushless direct current motor control system is different from that of other motor control systems, and the dual-redundancy brushless direct current motor control system mainly comprises a permanent magnet, an iron core, a rotating shaft, a bearing, a stator winding, a power tube, a Hall sensor and a chip. In actual operation, the most prone parts of the control system to failure are the stator windings, the permanent magnets, the hall sensors, the power tubes, the control chip and the bearings. The service life of the current motor is mainly obtained by experimental measurement, namely the service life of the motor is measured when the motor runs to a fault. The method is to verify the whole motor through experiments, and does not consider each part. The method provided by the invention calculates each part which is most prone to failure, and finally obtains the total reliability of the dual-redundancy brushless direct current motor control system.

The invention provides a reliability calculation method for a dual-redundancy brushless direct current motor control system, which comprises the following steps of:

step 1: the main faults of the dual-redundancy brushless direct current motor control system are divided into winding faults, permanent magnet faults, Hall sensor faults, control chip faults, power tube faults and bearing faults.

Step 2: and calculating the failure rate and reliability of the stator winding of the dual-redundancy brushless direct current motor control system.

The failure rate of the first set of windings is: lambda [ alpha ]_p11＝λ_b1π_E1π_Q1π_K1π_C1

The failure rate of the second set of windings is: lambda [ alpha ]_p12＝λ_b1π_E1π_Q1π_K1π_C1

Considering that the service life of the windings of the dual-redundancy brushless direct current motor control system obeys single-parameter index distribution, and meanwhile, the reliability of the brushless direct current motor is improved by adopting a parallel structure mode for two sets of windings, so that the total reliability of the stator windings after t hours of working is as follows:

wherein λ is_b1Is the fundamental failure rate of the winding coil, pi_E1Is an environmental coefficient, pi_Q1Is a mass coefficient of pi_K1Is a coefficient of species, pi_C1Is a structural coefficient.

And step 3: and calculating the failure rate and reliability of the permanent magnet of the dual-redundancy brushless direct current motor control system.

The failure rate of the permanent magnet is as follows: lambda [ alpha ]_P2＝λ_b2π_E2π_Q2

The service life of the permanent magnet of the dual-redundancy brushless direct current motor control system is considered to be subjected to single-parameter exponential distribution, so that the reliability of the permanent magnet after working for t hours is obtained as follows:

wherein λ is_b2Is the basic failure rate of the permanent magnet, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient.

And 4, step 4: and calculating the failure rate and reliability of the Hall sensor of the dual-redundancy brushless direct current motor control system.

λ_P3＝λ_b3π_E3π_Q3π_A3π_K3π_C3π_r3

Wherein λ is_b3To a basic failure rate, pi_E3Is an environmental coefficient, pi_Q3Is a mass coefficient of pi_A3Using the coefficient, pi_K3Is a coefficient of species, pi_C3Is a coefficient of structure, pi_r3The rated power coefficient.

Considering that the service life of the winding of the dual-redundancy brushless direct current motor control system obeys single-parameter index distribution, and adopting a mode of connecting three Hall position sensors in series in position detection of the dual-redundancy brushless direct current motor control system, the reliability of the Hall position sensors after working for t hours is as follows:

wherein λ is_b2For basic failure rate of rotor, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient of pi_K2Is a coefficient of species, pi_C2Is a structural coefficient.

And 5: and calculating the failure rate and reliability of the control chip of the dual-redundancy brushless direct current motor control system.

The failure rate of the control chip is as follows: lambda [ alpha ]_P4＝π_Q4[C₁π_T4π_V4+(C₂+C₃.)π_E4)]π_L4

The service life of the control chip is considered to be subjected to single-parameter exponential distribution, and the reliability of the chip after t hours of operation is as follows:

wherein, pi_E4Is an environmental coefficient, pi_Q4Is a mass coefficient of pi_L4To the maturation factor,. pi_T4Is the temperature stress coefficient, pi_V4Coefficient of voltage stress, C₁And C₂For complex failure rate of circuit, C₃Package complexity failure rate.

Step 6: and calculating the failure rate and reliability of the power tube of the dual-redundancy brushless direct current motor control system.

One set of control circuit contains six power tubes, so the failure rate of the first set of power tubes is as follows:

similarly, the failure rates of the six power transistors in the second set of control circuit are as follows:

the service life of the power tube is considered to be subjected to exponential distribution, and the two sets of control circuits adopt a parallel structure, so that the total reliability of the power tube is as follows:

wherein λ is_b5For basic failure rate of rotor, pi_E2Is an environmental coefficient, pi_Q2Is a mass coefficient of pi_A5In order to apply the coefficients to the image data,is the voltage stress coefficient, pi_r5Product performance rating coefficient, pi_C5And (4) structural coefficient.

And 7: and calculating the bearing failure rate and reliability of the dual-redundancy brushless direct current motor control system.

The bearing failure rate is as follows:

the number of bearings in the dual-redundancy brushless direct current motor control system is 2, and the connection mode is series connection. The total reliability after t hours of operation was:

wherein P is the equivalent dynamic load borne by the rolling bearing, and n is the rotating speed of the bearing; f. of_QTemperature coefficient introduced to characterize basic dynamic load rating, f_pTo characterize the load factor induced by vibration or shock in operation; m is a shape parameter, and for a ball bearing, m is 10/9, a cylindrical roller bearing, m is 3/2, and a tapered roller bearing, m is 4/3; the ball bearing epsilon is 3, and the roller bearing epsilon is 10/3; c is the rated dynamic load of the rolling bearing, and the value of the rated dynamic load is related to the temperature and parameters of the bearing.

And 8: according to the reliability model of the dual-redundancy brushless direct current motor control system shown in fig. 1, the total reliability of the motor can be obtained as follows:

R(t)＝R₁×R₂×R₃×R₄×R₅×R_Z

example 1:

a dual-redundancy brushless direct current motor control system is provided, the rated voltage is 270V, the rated rotating speed is 1000r/min, the topological structure of a control circuit is shown in figure 2, and the reliability of the motor after 18000 hours (about 2 years) of operation is calculated.

Step 1: the main faults of the dual-redundancy brushless direct current motor control system are divided into winding faults, permanent magnet faults, Hall sensor faults, control chip faults, power tube faults and bearing faults.

Step 2: and calculating the failure rate and reliability of the stator winding of the dual-redundancy brushless direct current motor control system.

The failure rate of the first set of windings is: lambda [ alpha ]_p11＝λ_b1π_E1π_Q1π_K1π_C1

The failure rate of the second set of windings is: lambda [ alpha ]_p12＝λ_b1π_E1π_Q1π_K1π_C1

Take lambda_b1＝0.0205×10^-6，π_E1＝2，π_Q1＝0.6，π_K1＝1，π_C1The total reliability of the stator winding after 18000 hours of operation is 1:

and step 3: and calculating the failure rate and reliability of the permanent magnet of the dual-redundancy brushless direct current motor control system.

The failure rate of the permanent magnet is as follows: lambda [ alpha ]_P2＝λ_b2π_E2π_Q2

Take lambda_b2＝0.06×10^-6，π_E2＝1.5，π_Q2The reliability of the permanent magnet after 18000 hours of operation is thus obtained as:

and 4, step 4: and calculating the failure rate and reliability of the Hall sensor of the dual-redundancy brushless direct current motor control system.

λ_P3＝λ_b3π_E3π_Q3π_A3π_K3π_C3π_r3

Wherein λ is_b3＝0.151×10^-6，π_E3＝2，π_Q3＝0.05，π_A3＝0.7，π_K3＝1，π_C3＝1，π_r30.8. The total reliability of 3 hall sensors after 18000 hours of operation is:

and 5: and calculating the failure rate and reliability of the control chip of the dual-redundancy brushless direct current motor control system.

The failure rate of the control chip is as follows: lambda [ alpha ]_P4＝π_Q4[C₁π_T4π_V4+(C₂+C₃.)π_E4)]π_L4

Take pi_E4＝1.5，π_Q4＝0.08，π_L4＝1，π_T4＝0.38，π_V4＝1，C₁＝0.0731×10^-6，C₂＝0.0071×10^-6，C₃.＝4×10^-6The reliability after 18000 hours of operation is:

step 6: and calculating the failure rate and reliability of the power tube of the dual-redundancy brushless direct current motor control system.

One set of power tubes contains 6 power tubes, so the failure rate of the first set of power tubes is:

the failure rate of the second power transistor is therefore:

take lambda_b5＝0.071×10^-6，π_E2＝2，π_Q2＝0.03，π_A5＝0.7，π_r5＝0.8，π_C51, so that the power tubeThe total reliability after 18000 hours of operation is:

and 7: and calculating the failure rate and reliability of the bearing of the dual-redundancy brushless direct current motor control system.

The bearing failure rate is as follows:

taking P as 531N and N as 1000 r/min; f. of_Q＝1.1，f_p1.5, 10/9, 3, 680N. The total reliability of the two bearings after 18000 hours of operation is:

and 8: according to the reliability model of the dual-redundancy brushless direct current motor control system shown in fig. 1, six elements are connected in series, so that the total reliability of the motor working for 18000 hours can be obtained as follows:

R(18000)＝R₁×R₂×R₃×R₄×R₅×R_Z＝0.983816

therefore, the reliability of the dual-redundancy brushless direct current motor control system working for 18000 hours is 98.3816%.

The method comprises the steps of firstly determining each part which is easy to break down in the operation process in the dual-redundancy brushless direct current motor control system, and establishing a reliability model of the dual-redundancy brushless direct current motor control system according to the connection mode among the parts. The parts of the common dual-redundancy brushless direct current motor control system which are easy to malfunction are respectively: stator winding, permanent magnet, hall sensor, control chip, power tube and bearing. And finally, calculating the total reliability of the dual-redundancy brushless direct current motor control system through a reliability model. The invention realizes the accurate calculation of the reliability of the motor control system and improves the working benefit of the service life test of the dual-redundancy brushless direct current motor control system. Meanwhile, the reliability of the dual-redundancy brushless direct current motor control system can be actively improved in actual production operation through reliability calculation.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present disclosure.