A dual three-phase permanent magnet synchronous motor inverter active thermal management system

Abstract

The application provides a dual three-phase permanent magnet synchronous motor inverter active thermal management system, belonging to the field of motor drive and power electronics, comprising two sets of inverters, a speed control proportional-integral unit and a current decision unit; the two sets of inverters each correspond to a current control proportional-integral link, a coordinate transformation unit, a failure probability calculation unit, a space vector pulse width modulation unit and a temperature sampling unit. The system not only takes real-time temperature information of the inverter as a variable, but also introduces offline inverter life information and inverter system failure probability as control variables into the thermal management control algorithm, so that the control system not only adjusts the size of the two sets of winding currents according to the real-time inverter temperature information, but also introduces predictive information such as failure risk into the control system, to prevent inverter system overheating from the root cause, and truly realize active thermal management, rather than passively adjusting the inverter temperature.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of motor drive and power electronics, and particularly relates to an active thermal management system of a dual three-phase permanent magnet synchronous motor inverter. BACKGROUND

[0002] Dual redundant permanent magnet synchronous motors are widely used in the field of intelligent manufacturing equipment due to their redundancy and high reliability. Special application fields have high requirements for the reliability and service life of motors. Due to the special motor winding structure of dual redundant permanent magnet synchronous motors, two sets of inverters are needed to provide voltage. However, the junction temperature of the inverters rises and the heat is serious, which leads to reduced service life of the inverters and poor system performance.

[0003] Dual three-phase permanent magnet synchronous motor drive requires two sets of inverter circuits, and the core power electronic conversion components are power semiconductors, which are also the most vulnerable components. With the gradual improvement of semiconductor device manufacturing technology, the power level and density are also increasing. Under the same current, the thermal load that the power semiconductor device needs to withstand will be higher. If the internal temperature of the power semiconductor fluctuates greatly at this time, a large alternating thermal stress will be generated, which will affect the power cycle capability of the power semiconductor device and significantly reduce the service life of the power semiconductor device. More seriously, when the alternating thermal stress exceeds the junction temperature safety range of the power semiconductor device, failure will occur, leading to failure of the entire motor system.

[0004] In order to improve the reliability and performance of the dual three-phase permanent magnet synchronous motor inverter system, junction temperature control and efficiency optimization of the inverter system can be performed, i.e. active thermal management. At present, according to the control object, it can be mainly divided into four categories: system control, power control, device control and gate control. System control generally uses parallel devices to share power to improve loss distribution, and the time distribution is generally limited to 10ns; power control can be controlled by reducing the load current, controlling the DC bus voltage, improving power cycling, etc., and the control time is limited to 1ms; device control includes changing the switching frequency, adjusting the modulation mode, etc., and the time is limited to 100us; gate control mainly uses intelligent gate drive instead of pulse through algorithm, and the control time is limited to 1us.

[0005] At present, there are many active thermal management strategies for inverters, although there are many research results, in the type of power control method, the temperature of the inverter is often too high, and the temperature difference between the two sets of inverters is too large as the basic premise of the control algorithm, which has certain hysteresis in prolonging the overall system life. Moreover, various control methods are based on the control adjustment of the adverse phenomena occurred in the motor, and the control effect often does not have the predictive characteristics, which has limitations in preventing the overheating problem of the inverter from the root, so it is necessary to study the active thermal management control method of the dual-redundant permanent magnet synchronous motor inverter. SUMMARY

[0006] In order to overcome the deficiencies of the prior art, the present application provides a dual three-phase permanent magnet synchronous motor inverter active thermal management system.

[0007] In order to achieve the above purpose, the present application provides the following technical scheme:

[0008] A dual three-phase permanent magnet synchronous motor inverter active thermal management system, the inverter is two sets, corresponding to two sets of windings of the dual three-phase permanent magnet synchronous motor, for converting a direct current signal into a three-phase alternating current signal, for use of the dual three-phase permanent magnet synchronous motor, all the motors appearing below are dual three-phase permanent magnet synchronous motors.

[0009] The system comprises:

[0010] A speed control proportional-integral unit, the output of which is the total reference given value Iq_ref of the motor q-axis current;

[0011] A current decision unit for changing the size of the current in the two sets of windings by controlling the distribution of Iq_ref, and actually controlling the power of the inverter to change the thermal stress of the two sets of inverters due to temperature rise;

[0012] Each of the inverters corresponds to:

[0013] A current control proportional-integral unit, the input of which is the reference given value of the motor q-axis current distributed by the current decision unit and the d-axis current given value in one set of windings, and the output of which is the voltage of the d-axis and q-axis of one set of windings;

[0014] A coordinate transformation unit receiving the voltage of the d-axis and q-axis of the windings output by the current control proportional-integral unit, and transforming the voltage into the voltage value in the alpha-beta coordinate system of the motor stator side;

[0015] A space vector pulse width modulation unit SVPWM receiving the voltage value in the alpha-beta coordinate system of the motor stator side output by the coordinate transformation unit, and outputting the control signal of the inverter through sector judgment and vector action time calculation;

[0016] a temperature sampling unit for collecting junction temperature value of the inverter;

[0017] a failure probability calculation unit receiving the junction temperature value from the temperature sampling unit, calculating the failure risk probability value corresponding to the inverter by using Bayes theorem, and outputting the failure risk probability value to the current decision unit.

[0018] Preferably, the input of the rotating speed control proportional-integral unit is the difference between the actual rotating speed N of the motor and the given rotating speed N _ref .

[0019] Preferably, the input of the current control proportional-integral unit corresponding to one set of the inverter is the reference given value Iq_ref1 of the motor q-axis current allocated by the current decision unit and the given value Id_ref1 of the d-axis current in one set of windings; and the output is the d-axis and q-axis voltage U q1 , U d1 of the windings.

[0020] The input of the current control proportional-integral unit corresponding to another set of the inverter is the reference given value d_ref2 of the motor q-axis current allocated by the current decision unit and the given value Id_ref2 of the d-axis current in another set of windings; and the output is the d-axis and q-axis voltage U q2 , U d2 of the windings.

[0021] The coordinate conversion unit receives the q-axis and d-axis voltages U q1 , U d1 , U q2 , U d2 of the two sets of windings, converts the voltage values in the synchronous rotating coordinate system into voltage values U α and U β in the motor stator side α-β coordinate system.

[0022] Preferably, the failure probability calculation unit calculates the failure risk probability value by:

[0023] calculating the life prediction value of the inverter: according to the junction temperature value of the inverter, the life prediction value of the inverter is obtained by rain flow counting method;

[0024] calculating the system failure risk warning threshold: the prediction value of the life prediction value of the inverter corresponding to the two sets of windings below 90% of the average value of the life prediction value is taken as the failure risk warning threshold;

[0025] The failure risk probability is calculated: define event B as the junction temperature of the inverter being higher than a certain temperature alarm threshold, the junction temperature sampling value obtained by the temperature sampling unit, and the alarm threshold being 10% higher than the average junction temperature; define event A as the system failure risk being higher than a certain alarm threshold; the probability P(B|A) is the probability of the inverter junction temperature being higher than the temperature alarm threshold when the system failure risk is higher than the alarm threshold; and the probability P(A|B) is the probability of the system failure when the inverter temperature is higher than the alarm threshold.

[0026] The Bayes estimation theorem is used: The failure risk probability value P(A|B) is calculated and input as a variable to the current decision unit.

[0027] Preferably, the current decision unit adopts the following current distribution decision scheme:

[0028] The general service life of the power switch tube in the inverter is taken as a time period T, the time period T is divided into i parts, each part of the time period is T, and the i-th time period is T i , i=1, 2, 3…10.

[0029] Define m1 and m2 as the distribution coefficients of the current given value Iq_ref of the two sets of inverters, and m1+m2=1.

[0030] In the period T1, let m1=m2, i.e., Iq_ref1=Iq_ref2=0.5Iq_ref, and the current is equally divided.

[0031] In the periods T1 and T2, the failure risk probability calculated by the failure probability calculation unit is P(A|B)1 and P(A|B)2, and m1 and m2 are adjusted according to the failure probability, satisfying

[0032] In the remaining periods T3-T 10 , the above method of calculating the distribution coefficient of the current given value Iq_ref is used.

[0033] Preferably, the failure risk probability P(B|A) is a fixed value of 0.25.

[0034] Preferably, the q-axis and d-axis voltages U q1 , U d1 and U q2 , U d2 of the two sets of windings are transformed into the voltage values U 2r / 2s and U α in the α-β coordinate system of the motor stator side by a transformation matrix T β , and specifically:

[0035]

[0036] wherein U d is the d-axis voltage of the two sets of windings U d1 and U d2 , U q is the q-axis voltage of the two sets of windings U q1 and U q2 ;

[0037] T 2r / 2s is the transformation matrix, θ refers to the angle between the d-axis of the synchronous rotating coordinate system and the alpha-axis of the stator-side coordinate system.

[0038] Preferably, the temperature sampling unit collects the junction temperature values of the inverters by using infrared probes or temperature sensors.

[0039] Preferably, the torque ripple of the motor when it is working normally is smaller than the torque ripple when it is working with single winding; when the current values in the two sets of windings are the same, the torque of the motor is theoretically 2 times that of each winding.

[0040] The active thermal management system for the dual three-phase permanent magnet synchronous motor inverter provided by the application has the following beneficial effects:

[0041] On the premise that the total power remains unchanged, the junction temperature values of the two sets of inverters are collected by the temperature sampling unit, and then the failure risk probability of the inverters corresponding to each inverter temperature is calculated by the failure probability calculation unit, and the control algorithm of the failure risk probability is introduced to control the q-axis current given value I q_ref of the two windings, and then the temperatures of the two sets of inverters are adjusted, so that the active thermal management strategy of dynamic thermal balance is realized. The application takes the "non-occurring" failure risk probability as the starting point of the control algorithm, predicts the failure risk of the two sets of inverters through the existing temperature data, so as to prevent the situation of too high temperature of the inverters and too large temperature difference between the two sets of inverters from occurring in advance, and thus the failure risk of the system is reduced from the root. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the application and the design scheme thereof, the drawings required by the embodiments will be briefly introduced as follows. The drawings in the following description are only partial embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the premise of the drawings.

[0043] Figure 1 It is a topology diagram of the active thermal management system for the dual three-phase permanent magnet synchronous motor inverter of the embodiment 1 of the application.

[0044] Explanation of reference signs:

[0045] 1-speed control proportional-integral unit, 2-current decision unit, 3-current control proportional-integral unit, 4-coordinate transformation unit, 5-failure probability calculation unit, 6-space vector pulse width modulation unit SVPWM, 7-temperature sampling unit, 8-inverter, 9-dual redundant permanent magnet synchronous motor. DETAILED DESCRIPTION

[0046] In order to make the technical scheme of the present application better understood and implemented by those skilled in the art, the present application will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and cannot be used to limit the protection scope of the present application.

[0047] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the technical scheme of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0048] In addition, the terms "first", "second" and the like are only used for description purposes and cannot be understood as indicating or implying relative importance. In the description of the present application, it should be noted that unless otherwise explicitly specified or limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more, which will not be described in detail here.

[0049] Example 1

[0050] The present application provides a dual three-phase permanent magnet synchronous motor inverter active thermal management system, specifically as Figure 1As shown, including the speed control proportional-integral unit 1, current decision unit 2, current control proportional-integral unit 3, coordinate transformation unit 4, failure probability calculation unit 5, space vector pulse width modulation unit 6, temperature sampling unit 7, inverter 8, double redundant permanent magnet synchronous motor 9 (hereinafter referred to as motor), a total of nine parts. Among them, the double three-phase permanent magnet synchronous motor 9 contains two sets of windings, and the torque ripple when working is smaller than that when single winding works; when the current values of the two sets of windings are the same, the torque of the motor is about 2 times that of each winding; at the same time, the characteristics of the two sets of windings greatly increase the reliability and redundancy of the entire motor system. The inverter 8 is two sets, corresponding to the two sets of windings of the motor, for converting DC signals into three-phase AC signals for the motor.

[0051] The purpose of the application is to use the failure probability of Bayesian estimation and the actual temperature of the inverter as control variables, to change the current size in the two sets of windings of the motor considering the failure risk of the inverter, to reduce the temperature of the inverter system; make the junction temperature fluctuation of the inverter system reduce, improve the service life of the inverter and reduce the failure risk, and then improve the service life of the entire manufacturing equipment power system.

[0052] Specifically, the structure of the whole double three-phase motor inverter active thermal management control system is as follows:

[0053] The input of the speed control proportional-integral unit 1 is the difference between the actual speed N of the motor and the given speed N _ref , and the output is the total reference given value Iq_ref of the motor q-axis current.

[0054] The current decision unit 2 is used to change the current size in the two sets of windings by controlling the distribution of Iq_ref, and the power of the inverter is actually controlled to change the thermal stress of the two sets of inverters 8 due to temperature rise. The core point of the application is different from the general two sets of winding current average distribution strategy Considering the inherent difference characteristics of the material, microstructure and factory life of the power switch tube in the inverter system, and the most critical influencing factor is temperature.

[0055] Each set of inverter 8 corresponds to:

[0056] The current control proportional-integral unit 3 takes as input the reference setpoint value of the motor's q-axis current allocated by the current decision unit 2 and the setpoint value of the d-axis current in one set of windings, and outputs the voltages of one set of windings along the d and q axes. The coordinate transformation unit 4 receives the winding d-axis and q-axis voltages output by the current control proportional-integral unit 3 and converts them into voltage values ​​in the α-β coordinate system on the motor stator side. The space vector pulse width modulation unit SVPWM6, to achieve accurate output voltage control, takes as input the voltage values ​​in the α-β coordinate system on the motor stator side output by the coordinate transformation unit 4, and outputs the inverter's control signal through sector judgment and vector action time calculation. After receiving the control signal output by the space vector pulse width modulation unit SVPWM6, the inverter 8 converts the DC signal into a three-phase AC signal for use by the dual three-phase permanent magnet synchronous motor.

[0057] Specifically, in this embodiment, the input of the current control proportional-integral unit 3 corresponding to one inverter 8 is the reference setpoint Iq_ref1 of the motor q-axis current allocated by the current decision unit 2 and the setpoint Id_ref1 of the d-axis current in one winding; the output is the voltage U of the d-axis and q-axis of the winding. q1 U d1 The input to the current control proportional-integral unit 3 corresponding to the other inverter 8 is the reference setpoint d_ref2 of the motor q-axis current allocated by the current decision unit 2 and the setpoint Id_ref2 of the d-axis current in another winding; the output is the voltage U of the d-axis and q-axis of this winding. q2 U d2 .

[0058] Coordinate transformation unit 4 obtains the q-axis and d-axis voltages U from the two sets of windings of the current-controlled proportional-integral unit 3. q1 U d1 and U q2 U d2 The voltage value changed from the synchronous rotating coordinate system (dq coordinate system) to the voltage value U in the α-β coordinate system on the stator side of the motor. α and U β .

[0059] Temperature sampling unit 7 is used to collect the junction temperature value of inverter 8. Specifically, in this embodiment, temperature sampling unit 7 uses an infrared probe or temperature sensor to collect the junction temperature value of inverter 8.

[0060] The failure probability calculation unit 5 takes in the temperature sampling value of the inverter system collected by the temperature sampling unit 7, calculates the failure risk probability value of the inverter using Bayes' theorem, outputs P1 as the failure probability of the first inverter system, outputs P2 as the failure probability of the second inverter system, and outputs the failure risk probability value to the current decision unit 2.

[0061] Specifically, in this embodiment, the failure probability calculation unit 5 calculates the failure risk probability value including:

[0062] Rainflow counting method predicts the life of the inverter: the device junction temperature value sampled by the temperature sampling unit 7 can be obtained by the rainflow counting method to obtain a set of winding inverter life prediction values.

[0063] Calculate the failure risk warning threshold of the system: the prediction value of the life prediction value of the inverter corresponding to the two sets of windings below 90% of the average life prediction value is taken as the failure risk warning threshold.

[0064] Bayes theorem calculates the failure risk probability: define event B as the inverter junction temperature being higher than a certain temperature warning threshold, and the junction temperature sampling value obtained by the temperature sampling unit 7 is defined as the warning threshold value higher than 10% of the average junction temperature; define event A as the system failure risk being higher than a certain warning threshold. The probability P(B|A) is the probability that the inverter junction temperature is higher than the temperature warning threshold when the system failure risk is higher than the warning threshold. Since there are many reasons for system failure, a fixed value of 0.25 is taken for convenience of analysis; the probability P(A|B) is the probability of system failure when the inverter temperature is higher than the warning threshold.

[0065] Finally, the Bayes estimation theorem is used: The failure risk probability value P(A|B) is calculated and input to the current decision unit 2 as a variable.

[0066] Specifically, the current decision unit 2 adopts the following current distribution decision scheme based on the received above failure risk probability value:

[0067] The general service life of the power switch tube in the inverter is taken as the time period T, and the time period T is divided into i parts, and each time period is T, the i-th time period is T i , i=1, 2, 3…10.

[0068] Define m1 and m2 as the distribution coefficients of the current given value Iq_ref of the two sets of inverters, and satisfy m1+m2=1.

[0069] Let m1=m2 in period T1, that is, Iq_ref1=Iq_ref2=0.5Iq_ref, and the current is equally divided.

[0070] In periods T1 and T2, the failure risk probability obtained by the failure probability calculation unit 5 is P(A|B)1 and P(A|B)2, and m1 and m2 are adjusted according to the failure probability to satisfy

[0071] In the remaining periods T3-T 10In the embodiment, the distribution coefficient of the given current value Iq_ref is calculated by the above method.

[0072] In the embodiment, the probability P(B|A) is a fixed value 0.25.

[0073] In the embodiment, the q-axis and d-axis voltages U q1 , U d1 and U q2 , U d2 of the two sets of windings are transformed by a transformation matrix T 2r / 2s into the voltage values U α and U β in the stator-side α-β coordinate system, and the transformation is as follows:

[0074]

[0075] wherein U d is the d-axis voltage U d1 and U d2 of the two sets of windings, and U q is the q-axis voltage U q1 and U q2 of the two sets of windings.

[0076] T 2r / 2s is a transformation matrix, θ is the angle between the d-axis of the synchronous rotating coordinate system and the α-axis of the stator-side coordinate system.

[0077] In the embodiment, the torque ripple of the motor is smaller than that when the motor is operated with a single winding, and the torque of the motor is theoretically twice that of each winding when the current values of the two sets of windings are the same.

[0078] Based on the active thermal management system of the dual three-phase permanent magnet synchronous motor inverter proposed in the embodiment, the application further proposes an inverter active thermal management control method based on Bayesian estimation, and the control process mainly includes the following steps:

[0079] Step 1: sampling the temperature of the two sets of inverter systems of the dual three-phase permanent magnet synchronous motor to obtain temperature data.

[0080] Step 2: inputting the sampled temperature data into a failure probability calculation unit to obtain the failure risk probability of the two sets of inverters.

[0081] Step 3: inputting the obtained failure risk probability into a current decision unit, and here the given value I q_refThe ratio coefficients m1 and m2 of the two sets of windings are adjusted, the power distribution of the two sets of windings is adjusted under the condition that the total power remains unchanged, dynamic thermal management is realized, the winding with high failure risk is allocated with small power, and the winding with low failure risk is allocated with large power, the power distribution is continuously adjusted, the dynamic active thermal management control strategy is realized, and the overall service life of the motor system is prolonged.

[0082] The application provides an inverter active thermal management control method based on Bayesian estimation for a double-redundant permanent magnet synchronous motor used in the field of intelligent manufacturing equipment.

[0083] The application collects the junction temperature values of the two sets of inverters through a temperature sampling unit, and then calculates the failure risk probability of the inverters corresponding to the temperature of the inverters through a data processing link, so that the q-axis current given value I q_ of the two windings is controlled through a control algorithm introducing the failure risk probability, the ratio of the two sets of inverters is adjusted, the temperature of the two sets of inverters is adjusted, and the active thermal management strategy of dynamic thermal balance is realized.

[0084] The double-redundant permanent magnet synchronous motor provided by the application effectively solves the problem of uneven current between the two sets of windings when the load suddenly changes during operation, and the average current effect is significantly improved compared with the traditional method.

[0085] The above-described embodiments are only preferred specific embodiments of the application, and the protection scope of the application is not limited thereto, and any person skilled in the art can obtain simple changes or equivalent replacements of the technical solutions within the technical range disclosed by the application, which all belong to the protection scope of the application.

Claims

1. A dual three-phase permanent magnet synchronous motor inverter active thermal management system, the inverter (8) is two sets, corresponding to the two sets of windings of the motor respectively, for converting direct current signal into three-phase alternating current signal for the motor to use, characterized in that, The system comprises: a speed control proportional-integral unit (1) whose output is the total reference given value Iq_ref of the motor q-axis current; a current decision unit (2) for changing the size of the current in the two sets of windings by controlling the distribution of Iq_ref, and actually controlling the power of the inverter to change the thermal stress of the two sets of inverters (8) due to temperature rise; each set of the inverter (8) corresponds to: a current control proportional-integral unit (3) whose input is the reference given value of the motor q-axis current distributed by the current decision unit (2) and the given value of the d-axis current in one set of windings, and whose output is the d-axis and q-axis voltage of one set of windings; a coordinate conversion unit (4) receiving the d-axis and q-axis voltage of the windings output by the current control proportional-integral unit (3) and converting the voltage into the voltage value in the motor stator side α-β coordinate system; a space vector pulse width modulation unit SVPWM (6) receiving the voltage value in the motor stator side α-β coordinate system output by the coordinate conversion unit (4) and outputting the control signal of the inverter through sector judgment and vector action time calculation; a temperature sampling unit (7) for collecting the junction temperature value of the inverter (8); a failure probability calculation unit (5) receiving the junction temperature value from the temperature sampling unit (7), calculating the failure risk probability value corresponding to the inverter by using Bayes theorem, and outputting the failure risk probability value to the current decision unit (2).

2. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 1, wherein, The input of the speed control proportional-integral unit (1) is the difference between the actual motor speed N and the given speed N _ref .

3. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 1, wherein, The input of the current control proportional-integral unit (3) of the set of inverters (8) is assigned the reference given value Iq_ref1 of the motor q-axis current assigned by the current decision unit (2) and the given value Id_ref1 of the d-axis current in the set of windings; the output is the voltage U q1 , U d1 ; The input of the current control proportional-integral unit (3) of the other set of the inverter (8) is assigned the reference given value d_ref2 of the motor q-axis current assigned by the current decision unit (2) and the given value Id_ref2 of the d-axis current in the other set of windings; the output is the voltage U q2 , U d2 of the d-axis and q-axis of the windings The coordinate transformation unit (4) receives two sets of q-axis and d-axis winding voltages U q1 , d1 and U q2 , d2 from the voltage values in the synchronous rotating coordinate system, and transforms them into voltage values U α and U β in the stator-side α-β coordinate system of the motor.

4. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 1, wherein, The failure probability calculation unit (5) includes: calculating the inverter life prediction value: according to the junction temperature value of the inverter (8), the inverter life prediction value is obtained by rain flow counting method; calculating the system failure risk warning threshold: the prediction value of the inverter life prediction value corresponding to the two sets of windings below 90% of the average value of the life prediction value is taken as the failure risk warning threshold; calculating the failure risk probability: defining event B as the inverter junction temperature being higher than a certain temperature warning threshold, the junction temperature sampling value obtained by the temperature sampling unit (7) is regulated as the warning threshold being 10% higher than the average value of the obtained junction temperature; defining event A as the system failure risk being higher than a certain warning threshold; then the probability P(B|A) is the probability of the inverter junction temperature being higher than the temperature warning threshold when the system failure risk is higher than the warning threshold; the probability P(A|B) is the probability of the system failure when the inverter temperature is higher than the warning threshold; Using the Bayes estimation theorem: The failure risk probability value P(A|B) is calculated and input as a variable to the current decision unit (2).

5. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 4, wherein, The current decision unit (2) adopts the following current distribution decision scheme: With the general service life of the power switch tube in the inverter as a time period T, the time period T is divided into i parts, each part of the time period is T, the i-th time period is T i , i = 1, 2, 3…10; defining m1 and m2 as the distribution coefficients of the current given value Iq_ref of the two sets of inverters and satisfying m1+m2=1; in the period T1, let m1=m2, i.e. Iq_ref1=Iq_ref2=0.5Iq_ref, the current is equally divided; In the period T1 and the period T2, the failure risk probability P(A|B)1 and P(A|B)2 obtained by the failure probability calculation unit (5) are adjusted to the sizes of m1 and m2, respectively, to satisfy In the remaining period T3-T 10 The distribution factor of the given current value Iq_ref is calculated in the same way as above.

6. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 5, wherein, the failure risk probability P(B|A) takes a fixed value of 0.

25.

7. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 3, wherein, each q-axis and d-axis voltage U of the two sets of windings q1 , U d1 and U q2 , U d2 through a transformation matrix T 2r / 2s become voltage values U in the α-β coordinate system on the motor stator side α and U β , specifically: Among them, U d For the d-axis voltage U of the two sets of windings d1 and U d2 U q For the q-axis voltage U of the two sets of windings q1 and U q2 ; T 2r / 2s is a transformation matrix, θ denotes an angle between a d-axis of a synchronous rotating coordinate system and an α-axis of a stator-side coordinate system.

8. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 1, wherein, The temperature sampling unit (7) collects the junction temperature value of the inverter (8) by using an infrared probe or a temperature sensor.

9. The dual three-phase permanent magnet synchronous machine inverter active thermal management system of claim 1, wherein, When the motor is working normally, its torque ripple is smaller than that when a single winding is working; when the current values in the two sets of windings are the same, the torque of the motor is theoretically 2 times that of each winding.

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