Non-contact brush direct current coreless motor winding monitoring method

Abstract

The invention discloses a non-contact brush direct-current hollow cup motor winding monitoring method, which comprises the following steps of: 1) arranging a detection device which comprises a primary detection winding (102), a secondary detection winding (103) and an iron core (104); 2) carrying out circuit connection on the detection device; 3) performing parameter adjustment on the detection device, and measuring a winding turn-to-turn short circuit detection threshold value and a winding turn-to-turn disconnection detection threshold value; 4) putting the to-be-detected winding (101) into a gap between the primary detection winding (102) and the secondary detection winding (103); and 5) based on the winding turn-to-turn short circuit detection threshold value and the winding turn-to-turn disconnection detection threshold value, carrying out short circuit and / or disconnection detection on the winding (101) to be detected by using the detection device. The method is helpful for obviously improving the generation efficiency of the hollow cup brush direct current motor and reducing the production cost.

Description

Technical Field

[0001] This invention relates to the field of winding monitoring, specifically a non-contact method for monitoring the windings of a brushed DC coreless motor. Background Technology

[0002] In the manufacturing process of coreless brushed DC motors, non-destructive testing of the coreless windings is a crucial step in ensuring the quality of the final product and improving production efficiency. By identifying defects in the windings themselves early in the manufacturing process, it prevents problems from persisting into subsequent assembly stages, thereby achieving significant cost savings and proactive quality control.

[0003] Immediately inspecting the windings after manufacturing offers a significant cost advantage compared to discovering problems through performance testing after motor manufacturing is complete. The performance of coreless motors is highly dependent on the quality of the windings; defects such as broken wires and inter-turn short circuits can directly lead to abnormal motor operation or even failure. If these defects are only discovered during performance testing after final motor assembly, it not only requires substantial time for disassembly, fault location, and parts replacement, but may also result in the waste of other valuable components already assembled (such as commutators and magnets). Using non-destructive testing technology to screen out defective products during the winding stage avoids unnecessary subsequent processing and material losses, fundamentally reducing scrap rates and rework costs. This allows for early detection and handling of quality issues, effectively saving overall manufacturing costs.

[0004] However, traditional contact measurement methods (such as point-by-point detection using probes) are inefficient, difficult to automate fully, and may cause physical damage to precision windings. Current non-contact detection methods simply detect whether the winding has a broken wire by whether an induced current is generated in the winding in an alternating magnetic field, and cannot effectively detect short circuits between winding turns. Summary of the Invention

[0005] The purpose of this invention is to provide a non-contact method for monitoring the windings of a brushed DC coreless motor, comprising the following steps:

[0006] Step 1) Arrange the testing device, including the primary testing winding, the secondary testing winding, and the iron core;

[0007] Step 2) Connect the circuit of the detection device;

[0008] Step 3) Adjust the parameters of the detection device and determine the inter-turn short circuit detection threshold and the inter-turn open circuit detection threshold of the winding;

[0009] Step 4) Place the winding to be tested into the gap between the primary detection winding and the secondary detection winding;

[0010] Step 5) Based on the winding inter-turn short circuit detection threshold and the winding inter-turn open circuit detection threshold, use the detection device to perform short circuit and / or open circuit detection on the winding under test.

[0011] Furthermore, the number of coils, shape, and axial length of the primary and secondary detection windings are consistent with those of the winding under test.

[0012] Furthermore, the diameters of the primary and secondary detection windings are determined as follows: the gap length between the primary and secondary detection windings is greater than the diameter of the winding to be tested, which serves as a constraint, and the goal is to minimize the gap length between the primary and secondary detection windings.

[0013] Furthermore, the primary detection winding coils are sequentially numbered p1, p2…pn; the secondary detection winding coils are sequentially numbered s1, s2…sn. n n is the total number of coils contained in the winding to be tested;

[0014] The primary detection winding and the secondary detection winding are arranged in concentric circles, and the coils with the same number have the same axis direction.

[0015] All coils in the primary and secondary detection windings are wound in the same direction, and all terminals are independently led out for connecting to the power supply and data acquisition unit.

[0016] Furthermore, the secondary detection winding is wound on the iron core; the outer diameter of the iron core and the inner diameter of the secondary detection winding are the same.

[0017] Furthermore, in step 2), the step of connecting the circuit of the detection device includes:

[0018] Connect the ends of all coils in the primary detection winding together and ground them;

[0019] Each coil of the primary detection winding is connected to an independent switch at its starting end; the switches are numbered sequentially as sw1, sw2…sw n ;

[0020] Connect the other ends of all the switches together and connect them to a voltage- and frequency-controlled AC power supply.

[0021] Connect each coil of the secondary detection winding to the synchronous data acquisition unit.

[0022] Furthermore, in step 3), the step of adjusting the parameters of the detection device includes:

[0023] Step 3-1) Set the power conditions. After setting, turn off all switches.

[0024] Step 3-2) Set the parameters of the synchronous data acquisition unit, including adjusting the sampling rate and the length of a single sampling time;

[0025] Step 3-3) Turn on the power supply and set the initial value of k to 1;

[0026] Steps 3-4) Close switch sw k Other switches remain off;

[0027] (Steps 3-5) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding is acquired using a synchronous data acquisition device and denoted as ref. k_1 ref k_2 …ref k_n ;

[0028] Disconnect switch sw after data collection is complete k ;

[0029] Steps 3-6) Calculate the induced potential ref using FFT transformation k_k The fundamental amplitude is denoted as TH01. k ;

[0030] Steps 3-7) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as TH02. k ;

[0031] Wherein, when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0032] Step 3-8) Determine if k is greater than n. If not, let k = k + 1 and return to step 3-4. If yes, proceed to step 3-9.

[0033] Steps 3-9) Calculate the symmetry characteristic quantities of the detection device, i.e.:

[0034] (1)

[0035] (2)

[0036] In the formula, FI1 and FI2 are the symmetry characteristic quantities of the detection device;

[0037] Step 3-10) If the symmetry characteristic quantity FI1 or FI2 of the detection device is greater than 0.01, adjust or replace the detection device and return to step 3-1).

[0038] If both the symmetry characteristic quantities FI1 and FI2 of the detection device are less than or equal to 0.01, the adjustment ends.

[0039] Furthermore, the inter-turn open circuit detection threshold TH1 for the winding is as follows:

[0040] (3)

[0041] Where y1 is the margin coefficient corresponding to TH1;

[0042] The short circuit detection threshold for winding turns is TH2 = 0.015~0.02.

[0043] Furthermore, the steps for using a detection device to perform open-circuit detection on the winding under test include:

[0044] S1) Let the initial value of k be 1;

[0045] S2) Close switch swk, and keep other switches open;

[0046] S3) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding is collected using a synchronous data acquisition device and denoted as res. k_1 ,res k_2 …res k_n ;

[0047] Disconnect SW after data collection is complete. k .

[0048] S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5.

[0049] S5) Calculate res using FFT 1_1 ,res 2_2 …res n_n The fundamental amplitude is denoted as res11, res12…res1 n ;

[0050] S6) Calculate the characteristic quantity FI3 of the winding breakage, that is:

[0051] (4)

[0052] S7) If FI3 > TH1, it is determined that there is a broken wire in the winding, and the detection result "winding open circuit" is output; if FI3 ≤ TH1, it is determined that there is no open circuit fault in the winding.

[0053] Furthermore, the steps for short-circuit testing of the winding under test using a testing device include:

[0054] S1) Let the initial value of k be 1;

[0055] S2) Close switch swk, and keep other switches open;

[0056] S3) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding is collected using a synchronous data acquisition device and denoted as res. k_1 ,resk_2 …res k_n ;

[0057] Disconnect SW after data collection is complete. k .

[0058] S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5.

[0059] S5) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as res2. k Where: when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0060] S6) Calculate the inter-turn short-circuit characteristic quantity FI4 of the winding, that is:

[0061] (5)

[0062] S7) If FI4≤TH2, it is determined that there is no inter-turn short circuit in the winding under test, and the test result "winding is normal" is output, and the test ends; if FI3>TH2, it is determined that there is an inter-turn short circuit in the winding under test, and the test result "winding inter-turn short circuit" is output, and the test ends.

[0063] The technical effects of this invention are undeniable. This invention provides a non-contact method for detecting the windings of a coreless brushed DC motor, which can effectively detect winding breaks and inter-turn short circuits without contacting the windings. It can be used for the automated detection of coreless brushed DC windings, which helps to significantly improve the production efficiency of coreless brushed DC motors and reduce production costs. Attached Figure Description

[0064] Figure 1 is a schematic diagram of the winding detection device used in this invention;

[0065] Figure 2 is a schematic diagram of the circuit connection of the winding detection device used in this invention;

[0066] Figure 3 is a schematic diagram of the parameter adjustment and detection threshold determination process of the present invention;

[0067] Figure 4 is a schematic diagram of the winding detection and result judgment of the present invention;

[0068] In the diagram, 101: the hollow cup winding to be tested; 102: the primary winding of the testing device; 103: the secondary winding of the testing device; and 104: the core of the testing device. Detailed Implementation

[0069] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0070] Example 1:

[0071] See Figures 1 to 4 A non-contact method for monitoring the windings of a brushed DC coreless motor includes the following steps:

[0072] Step 1) Arrange the detection device, including primary detection winding 102, secondary detection winding 103 and iron core 104;

[0073] Step 2) Connect the circuit of the detection device;

[0074] Step 3) Adjust the parameters of the detection device and determine the inter-turn short circuit detection threshold and the inter-turn open circuit detection threshold of the winding;

[0075] Step 4) Place the winding to be tested 101 into the gap between the primary detection winding 102 and the secondary detection winding 103;

[0076] Step 5) Based on the short circuit detection threshold and the open circuit detection threshold between winding turns, use the detection device to perform short circuit and / or open circuit detection on the winding 101 under test.

[0077] Example 2:

[0078] The non-contact brushed DC coreless motor winding monitoring method is the same as that in Example 1. Furthermore, the number of coils, shape, and axial length of the primary detection winding 102 and the secondary detection winding 103 are consistent with those of the winding to be tested 101.

[0079] Example 3:

[0080] The non-contact brushed DC coreless motor winding monitoring method has the same technical content as any one of Embodiments 1-2. Further, the diameter of the primary detection winding 102 and the secondary detection winding 103 is determined as follows: the gap length between the primary detection winding 102 and the secondary detection winding 103 is greater than the diameter of the winding 101 to be tested, which is a constraint, and the goal is to minimize the gap length between the primary detection winding 102 and the secondary detection winding 103.

[0081] Example 4:

[0082] A non-contact brushed DC coreless motor winding monitoring method, with technical content identical to any one of embodiments 1-3, further wherein the primary detection winding 102 coils are sequentially numbered p1, p2…pn; and the secondary detection winding 103 coils are sequentially numbered s1, s2…sn… n n is the total number of coils contained in the winding to be tested;

[0083] The primary detection winding 102 and the secondary detection winding 103 are arranged in concentric circles, and the coils with the same number have the same axis direction.

[0084] The primary detection winding 102 and the secondary detection winding 103 are all wound in the same direction, and all terminals are independently led out for connecting the power supply and the data acquisition unit.

[0085] Example 5:

[0086] The non-contact brushed DC coreless motor winding monitoring method has the same technical content as any one of embodiments 1-4. Furthermore, the secondary detection winding 103 is wound on the iron core 104; the outer diameter of the iron core 104 and the inner diameter of the secondary detection winding 103 are the same.

[0087] Example 6:

[0088] The non-contact brushed DC coreless motor winding monitoring method, with technical content the same as any one of embodiments 1-5, further comprising the following steps in step 2): Connecting the detection device to the circuit.

[0089] Connect the ends of all coils in the primary detection winding 102 together and ground them;

[0090] Each coil of the primary detection winding 102 is connected to an independent switch at its start end; the switches are numbered sequentially as sw1, sw2…sw n ;

[0091] Connect the other ends of all the switches together and connect them to a voltage- and frequency-controlled AC power supply.

[0092] Connect each coil of the secondary detection winding 103 to the synchronous data acquisition unit.

[0093] Example 7:

[0094] The non-contact brushed DC coreless motor winding monitoring method is the same as any one of embodiments 1-6. Further, in step 3), the parameter adjustment step of the detection device includes:

[0095] Step 3-1) Set the power conditions. After setting, turn off all switches.

[0096] Step 3-2) Set the parameters of the synchronous data acquisition unit, including adjusting the sampling rate and the length of a single sampling time;

[0097] Step 3-3) Turn on the power supply and set the initial value of k to 1;

[0098] Steps 3-4) Close switch sw k Other switches remain off;

[0099] Steps 3-5) After a delay of time T (0.2s in this embodiment), the induced electromotive force of all coils in the secondary detection winding 103 is collected using a synchronous data acquisition device and denoted as ref. k_1 ref k_2 …ref k_n ;

[0100] Disconnect switch sw after data collection is complete k ;

[0101] Steps 3-6) Calculate the induced potential ref using FFT transformation k_k The fundamental amplitude is denoted as TH01. k ;

[0102] Steps 3-7) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as TH02. k ;

[0103] Wherein, when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0104] Step 3-8) Determine if k is greater than n. If not, let k = k + 1 and return to step 3-4. If yes, proceed to step 3-9.

[0105] Steps 3-9) Calculate the symmetry characteristic quantities of the detection device, i.e.:

[0106] (1)

[0107] (2)

[0108] In the formula, FI1 and FI2 are the symmetry characteristic quantities of the detection device;

[0109] Step 3-10) If the symmetry characteristic quantity FI1 or FI2 of the detection device is greater than 0.01, adjust or replace the detection device and return to step 3-1).

[0110] If both the symmetry characteristic quantities FI1 and FI2 of the detection device are less than or equal to 0.01, the adjustment ends.

[0111] Example 8:

[0112] The non-contact brushed DC coreless motor winding monitoring method is the same as any one of Examples 1-7, further wherein the winding inter-turn open circuit detection threshold TH1 is as follows:

[0113] (3)

[0114] Where y1 is the margin coefficient corresponding to TH1;

[0115] The short circuit detection threshold for winding turns is TH2 = 0.015~0.02.

[0116] Example 9:

[0117] The non-contact brushed DC coreless motor winding monitoring method, with technical content identical to any one of embodiments 1-8, further includes the following steps for using a detection device to perform open-circuit detection on the winding 101 under test:

[0118] S1) Let the initial value of k be 1;

[0119] S2) Close switch swk, and keep other switches open;

[0120] S3) After a delay of time T (0.2s in this embodiment), the induced electromotive force of all coils in the secondary detection winding 103 is collected using a synchronous data acquisition device and recorded as res. k_1 ,res k_2 …res k_n ;

[0121] Disconnect SW after data collection is complete. k .

[0122] S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5.

[0123] S5) Calculate res using FFT 1_1 ,res 2_2 …res n_n The fundamental amplitude is denoted as res11, res12…res1 n ;

[0124] S6) Calculate the characteristic quantity FI3 of the winding breakage, that is:

[0125] (4)

[0126] S7) If FI3 > TH1, it is determined that there is a broken wire in the winding, and the detection result "winding open circuit" is output; if FI3 ≤ TH1, it is determined that there is no open circuit fault in the winding.

[0127] Example 10:

[0128] The non-contact brushed DC coreless motor winding monitoring method, with technical content the same as any one of Embodiments 1-2, further includes the following steps for short-circuit detection of the winding 101 under test using a detection device:

[0129] S1) Let the initial value of k be 1;

[0130] S2) Close switch swk, and keep other switches open;

[0131] S3) After a delay of time T (0.2s in this embodiment), the induced electromotive force of all coils in the secondary detection winding 103 is collected using a synchronous data acquisition device and recorded as res. k_1 ,res k_2 …res k_n ;

[0132] Disconnect SW after data collection is complete. k .

[0133] S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5.

[0134] S5) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as res2. k Where: when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0135] S6) Calculate the inter-turn short-circuit characteristic quantity FI4 of the winding, that is:

[0136] (5)

[0137] S7) If FI4≤TH2, it is determined that there is no inter-turn short circuit in the winding under test, and the test result "winding is normal" is output, and the test ends; if FI3>TH2, it is determined that there is an inter-turn short circuit in the winding under test, and the test result "winding inter-turn short circuit" is output, and the test ends.

[0138] Example 11:

[0139] The non-contact brushed DC coreless motor winding monitoring method has the same technical content as any one of Examples 1-10, and calculates (ref... k_p1 -ref k_p2 When the fundamental amplitude of the winding 101 under test is reached, the coil induced potential collected during the open circuit detection of the winding 101 under test can be used.

[0140] Example 12:

[0141] A detection method for the windings of a hollow cup brushed DC motor is mainly used in the motor production process. It allows for individual testing of the processed windings and can detect whether there are inter-turn short circuits or open circuits in the windings.

[0142] Step 1: Prepare the testing equipment

[0143] 1-1) As Figure 1 The diagram shown is a schematic of the winding detection device used in this invention.

[0144] 1-2) The testing device consists of a primary winding, a secondary winding, and an iron core. The testing device needs to be manufactured according to the structural characteristics of the winding to be tested. Specifically, the number and shape of the coils in the primary and secondary windings are consistent with those of the winding to be tested (e.g., ...). Figure 1 As shown, the winding under test, the primary winding, and the secondary winding are all composed of 7 hexagonal coils.

[0145] 1-3) The inner diameter of the primary winding is slightly larger than the outer diameter of the winding to be tested, and the outer diameter of the secondary winding is slightly smaller than the inner diameter of the winding to be tested (the winding diameter is determined according to the process level, and the gap between the primary and secondary windings is minimized as much as possible while ensuring that the winding to be tested can be smoothly placed into the gap between the primary and secondary windings).

[0146] 1-4) The axial lengths of the primary and secondary windings are consistent with those of the winding under test;

[0147] 1-5) The primary winding coils are numbered p1, p2…pn, where the subscript n is the total number of coils in the winding under test. The secondary winding coils are numbered s1, s2…sn. n ;

[0148] 1-6) The primary and secondary windings are arranged in concentric circles, and the coils with the same number have the same axis direction;

[0149] 1-7) All coils of the primary and secondary windings are wound in the same direction, and all terminals are independently led out for connecting the power supply and the data acquisition unit (see step 2 for details).

[0150] 1-8) The secondary winding is tightly wound on a core. The core is a hollow cylinder with the same outer diameter as the inner diameter of the secondary winding, a radial thickness of 1mm-2mm, and an axial length of the same as the secondary winding. It is made of silicon steel sheets stacked axially.

[0151] Step 2: Circuit connection of the detection device

[0152] 2-1) As shown in Figure 2, this is a schematic diagram of the circuit connection of the winding detection device used in this invention.

[0153] 2-2) The ends of all coils in the primary winding are connected together and grounded; the beginning of each coil in the primary winding is connected to an independent switch (either a relay or a power electronic switch), and the switches are numbered sequentially as sw1, sw2…sw n The serial numbers match the serial numbers of the connected coils, and all switches remain off by default.

[0154] 2-3) Connect the other side of all switches together to a voltage- and frequency-adjustable AC power supply (the power supply voltage should not be lower than the rated voltage of the motor corresponding to the winding under test, and the frequency range should be 1kHz-10kHz). Each coil of the secondary winding is connected to a synchronous data acquisition unit, and the sampling frequency of the acquisition unit should not be less than 200kSa / s.

[0155] Step 3: Parameter adjustment and detection threshold determination

[0156] 3-1) The coil to be tested is not placed in the detection device;

[0157] 3-2) Close SW1, keeping other switches open. The AC power supply outputs a sinusoidal AC voltage. Observe the current through the power supply (if the power supply has no current monitoring, an ammeter needs to be added to the power supply output). Observe the induced electromotive force of coil S1 through the data acquisition device. Adjust the voltage and frequency output of the AC power supply so that the current density in coil P1 does not exceed 4A / mm². 2 The magnitude of the induced electromotive force of coil S1 is within 60%-80% of the data acquisition range, and the power supply frequency is generally within the range of 1kHz-10kHz. After the power supply conditions are met, disconnect all switches.

[0158] 3-3) Set the parameters of the synchronous data acquisition unit, adjust the sampling rate to 20 times the power supply frequency, and set the single sampling time length to 10 times the power supply output voltage cycle;

[0159] 3-4) Keep the power on and the output parameters unchanged throughout the entire testing process;

[0160] 3-5) Let k=1;

[0161] 3-6) Close switch sw k Other switches remain off;

[0162] 3-7) Wait 0.2s, then start the synchronous data acquisition unit to collect the induced electromotive force of all secondary coils. Mark the collected time series as ref k_1 ref k_2 …ref k_n Disconnect SW after data collection is complete. k .

[0163] 3-8) Apply FFT to calculate the ref k_kThe fundamental amplitude (the average value of the entire time series) is denoted as TH01. k .

[0164] 3-9) Applying FFT, the calculated (ref) k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as TH02. k Where: when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0165] 3-10) Let k = k + 1, and repeat steps 3-6) to 3-9) until k = n.

[0166] 3-11) Calculate the symmetry characteristic quantity of the winding detection device according to the following formula:

[0167] ,

[0168] 3-12) If FI1 or FI2 is greater than 0.01, it means that the symmetry of the detection device does not meet the requirements. The detection device should be adjusted or redone to ensure the consistency and symmetry of each coil in the primary winding and secondary winding. After the adjustment is completed, repeat steps 3-1) to 3-12). If both FI1 and FI2 are less than 0.01, continue to perform the subsequent steps.

[0169] 3-13) Calculate the winding breakage diagnosis threshold TH1 according to the following formula:

[0170]

[0171] Where y1 is the margin coefficient corresponding to TH1, which is generally taken as 0.96~0.98.

[0172] 3-14) The inter-turn short-circuit detection threshold TH2 for windings is set to 0.015~0.02.

[0173] Step 4: Winding inspection and result judgment

[0174] 4-1) Place the winding to be tested in the gap between the primary and secondary windings of the testing device. The circumferential position of the winding to be tested does not need to correspond with the testing winding (the winding to be tested should be a finished hollow cup brushed DC motor winding, which consists of multiple coils connected end to end to form a closed loop).

[0175] 4-2) Let k=1;

[0176] 4-3) Close switch swk, and keep other switches open;

[0177] 4-4) Wait 0.2s, then start the synchronous data acquisition unit to collect the induced electromotive force of all secondary coils, and mark the collected time series as res. k_1 ,res k_2 …res k_n Disconnect SW after data collection is complete. k .

[0178] 4-5) Let k = k + 1, and repeat steps 4-3) to 4-4) until k = n.

[0179] 4-6) Apply FFT to calculate res 1_1 ,res 2_2 …res n_n The fundamental amplitude (the average value of the entire time series) is denoted as res11, res12…res1 n ;

[0180] 4-7) Calculate the characteristic quantity of winding breakage according to the following formula:

[0181]

[0182] 4-8) If FI3 > TH1, it is determined that there is a break in the winding, and the detection result "winding break" is output, and the detection ends; if FI3 ≤ TH1, it is determined that there is no break in the winding, and the inter-turn short circuit situation is further investigated:

[0183] 4-9) Let k=1;

[0184] 4-10) Applying FFT, the calculated (ref) k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as res2. k Where: when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n.

[0185] 4-11) Calculate the inter-turn short-circuit characteristic quantity of the winding according to the following formula:

[0186]

[0187] 4-12) If FI4≤TH2, it can be determined that there is no inter-turn short circuit in the winding under test, and the test result "winding is normal" is output, and the test ends; if FI3>TH2, it can be determined that there is an inter-turn short circuit in the winding under test, and the test result "winding inter-turn short circuit" is output, and the test ends.

[0188] Example 13:

[0189] The verification of the non-contact brushed DC coreless motor winding monitoring method is as follows:

[0190] Taking a 7-coil hexagonal hollow cup brushed DC motor winding as an example, finite element simulation is used to illustrate the achievable effect of this method:

[0191] The constructed simulation model is as follows Figure 1 As shown. Simulation of inter-turn short circuit: Each coil of the winding under test has 40 turns. In the simulation model, one of the coils is split into two parts at a ratio of 39:1. In the external circuit, the smaller part is short-circuited through a resistor to simulate an inter-turn short circuit. Simulation of winding breakage: In the external circuit, each coil is connected in series to form a loop through a resistor. Under normal circumstances, the resistance value is 1×10. -9 Ω, the resistance value when simulating a broken wire is 1×10 9 Ω.

[0192] Applying the method described in this invention, with TH2 set to 0.02, y1 set to 0.97, and TH1 = 3.257, the detection results under normal, inter-turn short circuit (single coil 1-turn short circuit), and open circuit conditions are shown below:

[0193] Table 1. Simulation analysis of winding detection based on finite element method

[0194] Winding status FI1 FI1>TH1? Wire breakage test results FI2 FI2>TH2? Inter-turn short circuit detection results normal 3.199 no No broken wires 0.002 no No inter-turn short circuit Inter-turn short circuit 3.198 no No broken wires 0.112 yes Inter-turn short circuit Broken wire 3.358 yes Broken wire - - -

[0195] As can be seen from the table above, FI1 for normal windings and inter-turn short-circuit windings is less than TH1, while FI1 for open-circuit windings is greater than TH1. This indicates that according to the present invention, open-circuit windings can be correctly and effectively identified. FI2 for normal windings is less than TH2, while FI2 for inter-turn short-circuit windings is greater than TH2. This indicates that according to the present invention, inter-turn short circuits can be correctly and effectively identified.

[0196] In summary, this invention introduces a non-contact method for detecting the windings of a coreless brushed DC motor. This method can effectively detect winding breaks and inter-turn short circuits without contacting the windings. It can be used for the automated detection of coreless brushed DC motor windings, which helps to significantly improve the production efficiency of coreless brushed DC motors and reduce production costs.

Claims

1. A non-contact method for monitoring the windings of a brushed DC coreless motor, characterized in that, Includes the following steps: Step 1) Arrange the detection device, including a primary detection winding (102), a secondary detection winding (103), and an iron core (104). Step 2) Connect the circuit of the detection device; Step 3) Adjust the parameters of the detection device and determine the inter-turn short circuit detection threshold and the inter-turn open circuit detection threshold of the winding; Step 4) Place the winding to be tested (101) into the gap between the primary detection winding (102) and the secondary detection winding (103); Step 5) Based on the short circuit detection threshold and the open circuit detection threshold between winding turns, use the detection device to perform short circuit and / or open circuit detection on the winding under test (101).

2. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The number of coils, shape, and axial length of the primary detection winding (102) and the secondary detection winding (103) are consistent with those of the winding to be tested (101).

3. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The diameters of the primary detection winding (102) and the secondary detection winding (103) are determined as follows: the gap length between the primary detection winding (102) and the secondary detection winding (103) is greater than the diameter of the winding to be tested (101) as a constraint, and the goal is to minimize the gap length between the primary detection winding (102) and the secondary detection winding (103).

4. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The primary detection winding (102) coils are numbered p1, p2…pn sequentially; the secondary detection winding (103) coils are numbered s1, s2…sn sequentially. n n is the total number of coils contained in the winding to be tested; The primary detection winding (102) and the secondary detection winding (103) are arranged in concentric circles, and the coils with the same number have the same axis direction. All coils of the primary detection winding (102) and the secondary detection winding (103) are wound in the same direction, and all terminals are independently led out for connecting the power supply and the data acquisition unit.

5. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The secondary detection winding (103) is wound on the iron core (104); the outer diameter of the iron core (104) is the same as the inner diameter of the secondary detection winding (103).

6. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, Step 2), the steps of connecting the circuit of the detection device include: Connect the ends of all coils of the primary detection winding (102) together and ground them; Each coil of the primary detection winding (102) is connected to an independent switch at its start end; the switches are numbered sequentially as sw1, sw2…sw n ; Connect the other ends of all the switches together and connect them to a voltage- and frequency-controlled AC power supply. Connect each coil of the secondary detection winding (103) to the synchronous data acquisition unit.

7. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, Step 3), the steps for adjusting the parameters of the detection device include: Step 3-1) Set the power conditions. After setting, turn off all switches. Step 3-2) Set the parameters of the synchronous data acquisition unit, including adjusting the sampling rate and the length of a single sampling time; Step 3-3) Turn on the power supply and set the initial value of k to 1; Steps 3-4) Close switch sw k Other switches remain off; (Steps 3-5) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding (103) is collected using a synchronous data acquisition device and denoted as ref. k_1 ref k_2 …ref k_n ; Disconnect switch sw after data collection is complete k ; Steps 3-6) Calculate the induced potential ref using FFT transformation k_k The fundamental amplitude is denoted as TH01. k ; Steps 3-7) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as TH02. k ; Wherein, when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n. Step 3-8) Determine if k is greater than n. If not, let k = k + 1 and return to step 3-4. If yes, proceed to step 3-9. Steps 3-9) Calculate the symmetry characteristic quantities of the detection device, i.e.: ；（1） ；（2） In the formula, FI1 and FI2 are the symmetry characteristic quantities of the detection device; Step 3-10) If the symmetry characteristic quantity FI1 or FI2 of the detection device is greater than 0.01, adjust or replace the detection device and return to step 3-1). If both the symmetry characteristic quantities FI1 and FI2 of the detection device are less than or equal to 0.01, the adjustment ends.

8. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The winding inter-turn open circuit detection threshold TH1 is shown below: ；（3） Where y1 is the margin coefficient corresponding to TH1; The short circuit detection threshold for winding turns is TH2 = 0.015~0.

02.

9. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 1, characterized in that, The steps for performing open-circuit detection on the winding (101) under test using a detection device include: S1) Let the initial value of k be 1; S2) Close switch swk, and keep other switches open; S3) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding (103) is collected using a synchronous data acquisition device and denoted as res. k_1 ,res k_2 …res k_n ; Disconnect SW after data collection is complete. k ; S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5. S5) Calculate res using FFT 1_1 ,res 2_2 …res n_n The fundamental amplitude is denoted as res11, res12…res1 n ; S6) Calculate the characteristic quantity FI3 of the winding breakage, that is: ；（4） S7) If FI3 > TH1, it is determined that there is a broken wire in the winding, and the detection result "winding open circuit" is output; if FI3 ≤ TH1, it is determined that there is no open circuit fault in the winding.

10. The non-contact brushed DC hollow cup motor winding monitoring method according to claim 9, characterized in that, The steps for short-circuit testing of the winding (101) under test using a testing device include: S1) Let the initial value of k be 1; S2) Close switch swk, and keep other switches open; S3) After a delay of time T, the induced electromotive force of all coils in the secondary detection winding (103) is collected using a synchronous data acquisition device and denoted as res. k_1 ,res k_2 …res k_n ; Disconnect SW after data collection is complete. k ; S4) Determine if k is greater than n. If not, set k = k + 1 and return to step S2. If yes, proceed to step S5. S5) Calculate using FFT transformation (ref k_p1 -ref k_p2 The fundamental amplitude of ) is denoted as res2. k Where: when k-2>0, p1=k-2; when k-2≤0, p1=k-2+n; when k+2≤n, p2=k+2; when k+2>n, p2=k+2-n. S6) Calculate the inter-turn short-circuit characteristic quantity FI4 of the winding, that is: ；（5） S7) If FI4≤TH2, it is determined that there is no inter-turn short circuit in the winding under test, and the test result "winding is normal" is output, and the test ends; if FI3>TH2, it is determined that there is an inter-turn short circuit in the winding under test, and the test result "winding inter-turn short circuit" is output, and the test ends.

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