Stator coil detection system and method

Abstract

The invention discloses a stator coil detection system and method. The detection system comprises an upper computer unit, a power supply unit, a detection unit and a cooling unit, wherein the upper computer unit is used for generating a control signal; the power supply unit is connected with a control signal, and the power supply unit is used for generating a three-phase variable current; the detection unit is respectively connected with a control signal and a three-phase variable current, and the detection unit heats an internal stator coil according to the control signal and the three-phase variable current; and the cooling unit is connected with a control signal and is in heat conduction connection with the detection unit, and the cooling unit is used for cooling the stator coil in the detection unit according to the control signal. According to the stator coil detection system and method, the stator coil is detected at-40 DEG C to 180 DEG C, and the motor stator can be electrified and heated through the three-phase variable current, so that the motor stator is subjected to insulation durability detection in an electrified state, and the detection sufficiency is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicle motors, and specifically relates to a stator coil detection system and method. Background Art

[0002] At present, electric motors are widely used as the power source for new energy vehicles. The motor is mainly composed of a rotor and a stator coil. The insulation performance of the stator coil is one of the most important indicators in automobile safety assessment. Therefore, it is necessary to fully verify the durability of the stator insulation. Good insulation performance can effectively prevent current leakage, short circuit and other faults, and improve the safety of new energy vehicles.

[0003] The insulation durability test of the motor stator in the prior art, such as the high and low temperature storage test and insulation resistance test of the motor, only tests the ambient temperature adaptability of the motor in a static state with no current flowing through the stator coil, and the ambient temperature range of the test is only -40℃~85℃. Therefore, this type of conventional high and low temperature static test is insufficient to verify the insulation durability of the motor stator.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a stator coil detection system and method. Summary of the invention

[0005] The object of the present invention is to provide a stator coil detection system and method, which can solve the technical problem that the high and low temperature static detection in the prior art is insufficient to verify the insulation durability of the motor stator.

[0006] In order to achieve the above object, a specific embodiment of the present invention provides a stator coil detection system, the detection system comprising: a host computer unit, a power supply unit, a detection unit and a cooling unit; wherein,

[0007] The host computer unit is used to generate a control signal;

[0008] The power supply unit is connected to the control signal, and the power supply unit is used to generate a three-phase variable current;

[0009] The detection unit is connected to the control signal and the three-phase variable current respectively, and the detection unit heats the internal stator coil according to the control signal and the three-phase variable current;

[0010] The cooling unit is connected to the control signal and is thermally connected to the detection unit. The cooling unit is used to cool the stator coil inside the detection unit according to the control signal.

[0011] In one or more embodiments of the present invention, the power supply unit includes a power supply and a frequency converter, wherein:

[0012] The power supply is used to provide a three-phase AC voltage;

[0013] The frequency converter is connected to the power supply, and is used to generate a three-phase variable current according to a three-phase AC voltage.

[0014] In one or more embodiments of the present invention, the power supply is connected to the inverter via a first three-phase AC line, the first three-phase AC power is 380V three-phase AC power, and the three-phase variable current is 0-250A three-phase AC current.

[0015] In one or more embodiments of the present invention, the detection unit includes a detection chamber and a temperature sensor, wherein:

[0016] The detection chamber is connected to a control signal, and the detection chamber is used to control the ambient temperature of the stator coil;

[0017] The temperature sensor is connected between the stator coil and the host computer unit, and is used to collect the temperature of the stator coil and feed it back to the host computer unit.

[0018] In one or more embodiments of the present invention, the cooling unit includes a deep chiller and a cooling water tower, wherein:

[0019] The cooling water tower is thermally connected to the detection chamber, and the cooling water tower is used to reduce the heat generated by the operation of the detection chamber equipment;

[0020] The input end of the deep chiller is thermally connected to the cooling tower, and the heat generated by the deep chiller during operation is taken away by the cooling water circulation of the cooling tower. The output end of the deep chiller is thermally connected to the stator coil, and the deep chiller is used to reduce the temperature of the stator coil.

[0021] In another aspect of the present invention, a stator coil detection method is provided, the detection method comprising the following steps:

[0022] During the heating period, the stator coil in the detection chamber is connected to a three-phase variable current and heated to a first target temperature;

[0023] During the cooling period, the three-phase variable current is cut off, and the stator coil in the detection chamber is cooled to a second target temperature by cooling water;

[0024] During the temperature recovery period, the stator coil is heated up to a third target temperature by increasing the temperature of the cooling water and / or the temperature of the detection chamber;

[0025] Obtain the insulation resistance value of the stator coil to the ground, and determine whether the insulation durability of the stator coil is qualified according to the resistance value of the stator coil to the ground;

[0026] The first target temperature is greater than the third target temperature, and the third target temperature is greater than the second target temperature.

[0027] In one or more embodiments of the present invention, the method further comprises:

[0028] An insulation resistance threshold of the stator coil to the ground is preset. If the insulation resistance value of the stator coil to the ground is greater than or equal to the preset resistance threshold of the stator coil, the insulation durability test of the stator coil is qualified; if the insulation resistance value of the stator coil to the ground is less than the preset resistance threshold of the stator coil, the insulation durability test of the stator coil is unqualified. The resistance threshold is 1 MΩ.

[0029] In one or more embodiments of the present invention, a cycle of the insulation durability detection method includes a heating period, a cooling period and a reheating period, a preset detection cycle number, and the resistance value of the stator coil is detected at the preset detection cycle number.

[0030] In one or more embodiments of the present invention, the method further comprises:

[0031] After heating the stator coil to a first target temperature by connecting the stator coil to a three-phase variable current, maintaining the stator coil at the first target temperature; and,

[0032] After the stator coil is cut off from the three-phase variable current and cooled to a second target temperature, the stator coil is maintained at the second target temperature.

[0033] In one or more embodiments of the present invention, the stator coil temperature detection range of the insulation durability detection method is: -40°C to 180°C

[0034] Compared with the prior art, the stator coil detection system and method of the present invention can energize and heat the motor stator through a three-phase variable current, so that the motor stator can be tested for insulation durability in a powered-on state to ensure the adequacy of the detection;

[0035] In addition, in the present invention, the stator coil is tested at -40°C to 180°C. Through high-frequency high-temperature and low-temperature switching, the insulation durability of the motor stator at different temperatures is fully considered, and the insulation resistance of the stator coil to the ground is measured during the testing process to further ensure the completeness and reliability of the testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1It is a structural schematic diagram of a stator coil detection system in one embodiment of the present invention;

[0038] Figure 2 FIG. 4 is a time-temperature curve diagram of a stator coil in a detection cycle in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] As described in the background technology, the insulation durability test of the motor stator in the prior art only tests the motor's adaptability to ambient temperature when the stator coil is static and no current is passed through it, and the ambient temperature range of the test is only -40°C to 85°C. Therefore, this type of conventional high and low temperature static test is insufficient to verify the insulation durability of the motor stator.

[0041] In response to the above problems, Figure 1 As shown, a stator coil insulation durability detection system in one embodiment of the present invention includes: a host computer unit 10, a power supply unit 20, a detection unit 30 and a cooling unit 40; wherein,

[0042] The host computer unit 10 is used to generate a control signal;

[0043] The power supply unit 20 is connected to the control signal, and the power supply unit 20 is used to generate a three-phase variable current;

[0044] The detection unit 30 is connected to the control signal and the three-phase variable current respectively, and the detection unit heats the internal stator coil 302 according to the control signal and the three-phase variable current;

[0045] The cooling unit 40 is connected to the control signal and is thermally connected to the detection unit 30 . The cooling unit 40 is used to cool the stator coil inside the detection unit 30 according to the control signal.

[0046] Among them, the upper computer unit 10 generates a control signal to control the power supply unit 20 to output a three-phase variable current to the detection unit 30 according to a preset time. The stator coil 302 inside the detection unit 30 is heated by the three-phase variable current to control the temperature of the surface of the stator coil 302. The control signal also controls the stator coil 302 inside the detection unit 30 by controlling the cooling unit 40 to perform further temperature control to ensure that the surface temperature of the stator coil 302 can reach the specified detection temperature and maintain the temperature, thereby ensuring the completeness of the detection.

[0047] In this embodiment, the power supply unit 20 includes a power supply 201 and a frequency converter 203, wherein:

[0048] The power supply 201 is used to provide a three-phase AC voltage;

[0049] The frequency converter 203 is connected to the power supply 201 , and is used to generate a three-phase variable current according to a three-phase AC voltage.

[0050] In this embodiment, the power supply 201 is connected to the frequency converter 203 via a first three-phase AC line 202, the first three-phase AC power is 380V three-phase AC power, and the three-phase variable current is 0-250A three-phase AC current.

[0051] In one embodiment, the detection unit 30 includes a detection chamber 301 and a temperature sensor 303, wherein:

[0052] The detection chamber 301 is connected to the control signal, and the detection chamber 301 is used to control the ambient temperature of the stator coil 302;

[0053] The temperature sensor 303 is connected between the stator coil 302 and the host computer unit 10 . The temperature sensor 303 is used to collect the temperature of the stator coil 302 and feed it back to the host computer unit 10 .

[0054] Among them, the motor stator is arranged in the detection chamber 301. In this embodiment, the detection chamber 301 can be provided with at least two groups of motor stators, that is, the detection chamber 301 can be used for detecting at least two groups of stator coils 302 at the same time; the temperature sensor 303 is used to detect the surface temperature of the stator coil 302 in real time and feed it back to the upper computer unit 10, and the upper computer unit 10 records the surface temperature of the stator coil 302.

[0055] In this embodiment, the cooling unit 40 includes a deep chiller 401 and a cooling water tower, wherein:

[0056] The cooling water tower is thermally connected to the detection chamber 301, and the cooling water tower is used to reduce the heat generated by the operation of the equipment in the detection chamber 301;

[0057] The input end of the deep chiller 401 is thermally connected to the cooling tower 402, and the cooling water circulation of the cooling tower takes away the heat generated when the deep chiller is running. The output end of the deep chiller 401 is thermally connected to the stator coil 302, and the deep chiller 401 is used to reduce the temperature of the stator coil 302.

[0058] Among them, the cooling tower 402 transports coolant to the detection chamber 301 through the first delivery pipe 60, and the detection chamber 301 transports the coolant after heat exchange back to the cooling tower 402 through the first return pipe 70, so as to control the temperature of the detection chamber 301; the input end of the deep chiller 401 is connected to the first delivery pipe 60 through the second delivery pipe 403, and the output end of the deep chiller 401 transports the coolant to the motor casing water path on the surface of the motor stator through the third delivery pipe 80, thereby controlling the temperature of the stator coil 302, and the motor casing water path is connected to the deep chiller 401 through the second return pipe 90 to reflux the coolant after heat exchange, and the coolant after heat exchange in the deep chiller 401 is transported back to the cooling tower 402 through the third return pipe 404, so as to control the temperature of the stator coil 302.

[0059] The present invention also provides a method for detecting the insulation durability of a stator coil, comprising the following steps:

[0060] During the heating period T r The stator coil 302 in the detection chamber 301 is connected to a three-phase variable current and heated to a first target temperature;

[0061] During the cooling period T d , cut off the three-phase variable current, and cool the stator coil 302 in the detection chamber 301 to a second target temperature through cooling water;

[0062] During the temperature recovery period T c , by increasing the temperature of the cooling water and / or the temperature of the detection chamber 301, the stator coil 302 is heated back to the third target temperature;

[0063] Obtaining the insulation resistance value of the stator coil 302 to the ground, and determining whether the insulation durability of the stator coil 302 is qualified according to the insulation resistance value of the stator coil 302 to the ground;

[0064] The first target temperature is greater than the third target temperature, and the third target temperature is greater than the second target temperature.

[0065] Among them, the heating period T r Including the first heating period T h1 and the first constant temperature period T k1 , cooling period T d Including the first cooling period T b1 , the second cooling period T b2 And the second constant temperature period Tk2 , temperature recovery period T c Including the second heating period T h2 and the third heating period T h3 .

[0066] In this embodiment, the stator coil 302 detection method further includes:

[0067] An insulation resistance threshold of the stator coil 302 to the ground is preset. If the insulation resistance value of the stator coil 302 to the ground is greater than or equal to the preset resistance threshold of the stator coil 302, the insulation durability test of the stator coil 302 is qualified. If the insulation resistance value of the stator coil 302 to the ground is less than the preset resistance threshold of the stator coil 302, the insulation durability test of the stator coil 302 is unqualified. The resistance threshold is 1 MΩ.

[0068] When the stator coil 302 is tested, it is necessary to ensure that the motor stator winding is under a DC voltage of 1000V for at least 30s, and the insulation resistance of the three-phase winding to the ground is greater than or equal to 1MΩ.

[0069] In this embodiment, one cycle of the insulation durability detection method includes a heating period, a cooling period and a reheating period, and a preset number of detection cycles are used to detect the resistance value of the stator coil 302 at the preset number of detection cycles.

[0070] The preset number of detection cycles is 600 times, and the insulation resistance of the three-phase winding of the stator coil 302 to the ground is detected once every 200 detection cycles.

[0071] Attached Figure 2 The temperature-time curve of the stator coil in a detection cycle of the present invention is shown in FIG. Figure 2 The detection cycle of the stator coil is further explained.

[0072] At time t0, the host computer unit 10 controls the inverter 203 to transmit a three-phase variable current to the stator coil 302, and the temperature of the stator coil 302 begins to rise until it reaches the first target temperature at time t1. t0-t1 is the first heating period T h1 , wherein the first target temperature is 180°C;

[0073] At time t1, the host unit 10 controls the three-phase variable current output by the inverter 203 according to the temperature information of the stator coil 302 fed back by the temperature sensor 303 to ensure that the temperature of the stator coil 302 is maintained at the first target temperature. t1-t2 is the first constant temperature period T k1 ;

[0074] At time t2, the host computer unit 10 controls the inverter 203 to stop transmitting the three-phase variable current to the stator coil 302, and sets the temperature of the detection chamber 301 to -40°C, and the temperature of the coolant in the deep chiller 401 to -30.5°C. At this time, the target temperature is set to the first transition temperature. At time t3, the surface temperature of the stator coil 302 is reduced to the first transition temperature. t2-t3 is the first cooling period T b1 , during the cooling period, the temperature dropped rapidly, and the first transition temperature was -20.5°C;

[0075] At time t3, the upper computer unit 10 controls to turn off the deep chiller 401, and cools the stator coil 302 only by detecting the temperature of the chamber 301, and reduces the surface temperature of the stator coil 302 to the second target temperature, which is -30.5°C. At time t4, the surface temperature of the stator coil 302 is reduced to -30.5°C. In this process, the stator coil 302 is cooled only by the chamber 301, and the temperature drops slowly to achieve precise temperature control. t3-t4 is the second cooling period T b2 ;

[0076] At time t4, the host computer unit 10 controls the detection chamber 301 so that the surface temperature of the stator coil 302 is maintained at the second target temperature until time t5, and t4-t5 is the second constant temperature period T k2 ;

[0077] At time t5, the upper computer unit 10 controls the temperature of the detection chamber 301 to 85°C, so that the surface temperature of the stator coil 302 returns to the second transition temperature, which is -20°C, until time t6. t5-t6 is the second heating period T h2 ;

[0078] At time t6, the upper computer unit 10 controls the temperature of the detection chamber 301 to 85°C, the temperature of the coolant in the deep chiller 401 to 40°C, sets the third target temperature to 25°C, and at time t7, the surface temperature of the stator coil 302 returns to 25°C. t6-t7 is the third heating period T h3 ;

[0079] At time t7, the next detection cycle of the stator coil 302 begins.

[0080] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0081] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A stator coil detection system, characterized in that: The detection system includes: a host computer unit, a power supply unit, a detection unit and a cooling unit; wherein, The host computer unit is used to generate a control signal; The power supply unit is connected to the control signal, and the power supply unit is used to generate a three-phase variable current; The detection unit is connected to the control signal and the three-phase variable current respectively, and the detection unit heats the internal stator coil according to the control signal and the three-phase variable current; The cooling unit is connected to the control signal and is thermally connected to the detection unit. The cooling unit is used to cool the stator coil inside the detection unit according to the control signal.

2. The stator coil detection system according to claim 1, characterized in that: The power supply unit includes a power supply and a frequency converter, wherein: The power supply is used to provide three-phase AC voltage; The frequency converter is connected to the power supply, and is used to generate a three-phase variable current according to a three-phase AC voltage.

3. The stator coil detection system according to claim 2, characterized in that: The power supply is connected to the frequency converter via a first three-phase AC line, the first three-phase AC power is 380V three-phase AC power, and the three-phase variable current is 0-250A three-phase AC current.

4. The stator coil detection system according to claim 1, characterized in that: The detection unit includes a detection chamber and a temperature sensor, wherein: The detection chamber is connected to a control signal, and the detection chamber is used to control the ambient temperature of the stator coil; The temperature sensor is connected between the stator coil and the host computer unit, and is used to collect the temperature of the stator coil and feed it back to the host computer unit.

5. The stator coil detection system according to claim 4, characterized in that: The cooling unit includes a deep chiller and a cooling water tower, wherein: The cooling water tower is thermally connected to the detection chamber, and the cooling water tower is used to reduce the heat generated by the operation of the detection chamber equipment; The input end of the deep chiller is thermally connected to the cooling tower, and the heat generated by the deep chiller during operation is taken away by the cooling water circulation of the cooling tower. The output end of the deep chiller is thermally connected to the stator coil, and the deep chiller is used to reduce the temperature of the stator coil.

6. A stator coil detection method, characterized in that: The detection method comprises the following steps: During the heating period, the stator coil in the detection chamber is connected to a three-phase variable current and heated to a first target temperature; During the cooling period, the three-phase variable current is cut off, and the stator coil in the detection chamber is cooled to a second target temperature by cooling water; During the temperature recovery period, the stator coil is heated up to a third target temperature by increasing the temperature of the cooling water and / or the temperature of the detection chamber; Obtain the insulation resistance value of the stator coil to the ground, and determine whether the insulation durability of the stator coil is qualified according to the resistance value of the stator coil to the ground; The first target temperature is greater than the third target temperature, and the third target temperature is greater than the second target temperature.

7. The stator coil detection method according to claim 6, characterized in that: The method further comprises: An insulation resistance threshold of the stator coil to the ground is preset. If the insulation resistance value of the stator coil to the ground is greater than or equal to the preset resistance threshold of the stator coil, the insulation durability test of the stator coil is qualified; if the insulation resistance value of the stator coil to the ground is less than the preset resistance threshold of the stator coil, the insulation durability test of the stator coil is unqualified. The resistance threshold is 1 MΩ.

8. The stator coil detection method according to claim 7, characterized in that: One cycle of the insulation durability detection method includes a heating period, a cooling period and a reheating period, and a preset number of detection cycles, during which the resistance value of the stator coil is detected.

9. The stator coil detection method according to claim 6, characterized in that: The method further comprises: After heating the stator coil to a first target temperature by connecting the stator coil to a three-phase variable current, maintaining the stator coil at the first target temperature; and, After the stator coil is cut off from the three-phase variable current and cooled to a second target temperature, the stator coil is maintained at the second target temperature.

10. The stator coil detection method according to claim 6, characterized in that: The stator coil temperature detection range of the insulation durability detection method is: -40°C to 180°C.

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