A method for weakening winding of offshore wind turbine generator additional loss

Abstract

The application discloses a method for weakening additional loss of a wind turbine generator at sea, and particularly relates to the field of energy-saving starting motors. The method reorganizes the winding path of a stator without changing the basic slot number of the stator core, the installation size of the motor, and the main winding pitch, positions the concentrated area of additional loss first, then distributes the phase belts and parallel branches in groups, and sets transposition leads and staggered cross-connections in the slots and at the ends, respectively, so that the same parallel branch experiences different slot depth positions and different end magnetic field positions within one pole pitch range, thereby weakening parallel branch circulating current, reducing additional loss at the slot opening, and reducing the risk of end eddy current.

Description

Technical Field

[0001] This invention relates to the field of energy-saving starter motor technology, and more specifically, to a method for reducing additional losses in the winding wiring of an offshore wind turbine. Background Technology

[0002] Energy-saving starter motors for offshore wind turbines are typically installed in humid, salt spray, vibration, and temperature-varying environments. These motors need to withstand large instantaneous currents during startup and maintain good efficiency during stable operation. Existing stator windings mostly adopt conventional distributed winding or conventional concentrated winding arrangements, with winding conductors arranged in fixed layers within the stator slots and the ends connected by traditional spans. This arrangement is technologically mature and facilitates mass production. However, under high-current startup and frequent start-stop conditions, leakage flux near the stator slot openings increases, the magnetic field distribution at the ends becomes uneven, and there is a difference in induced electromotive force between parallel branches, which easily leads to circulating current losses, skin losses, proximity losses, and additional end losses.

[0003] Existing technologies also employ methods such as thickening the conductors, increasing the insulation thickness, increasing the amount of varnish impregnation, and shortening the end length. These methods can improve mechanical strength or reduce some copper loss, but they do not pay enough attention to the differences in the electromagnetic environment of conductors at different radial positions in the stator slot, the local magnetic flux concentration in the end bridging section, or the potential deviation between parallel branches. Especially in energy-saving starter motors for offshore wind turbines, the motor needs to balance starting torque, operating efficiency, and moisture resistance. Simply increasing the amount of material will lead to problems such as increased slot fill factor, narrower heat dissipation channels, mismatched end stiffness, and increased manufacturing difficulty. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for reducing the additional losses of offshore wind turbine windings, which solves the problems mentioned in the background art through the following scheme.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for reducing additional losses in the winding wiring of an offshore wind turbine, comprising:

[0006] S1, Locating the loss zone: Divide the stator slot along the slot depth direction into slot opening layer, slot middle layer, and slot bottom layer. Mark the slot opening layer as slot opening loss zone. Mark the stator slot end inlet position as end inlet loss zone. Divide the area where the end bridging section is located into near slot end zone, middle end zone, and outer end zone, and form a loss zone record table.

[0007] S2, Determine the phase band wiring: Establish a phase band wiring table based on the loss area record table, divide the main power winding into U-phase main power winding, V-phase main power winding and W-phase main power winding, and assign the coil group in each phase main power winding to the first parallel branch, the second parallel branch, the third parallel branch and the fourth parallel branch accordingly.

[0008] S3, Set up transposition leads: According to the phase band wiring table, set up a layered transposition section in the slot in the end inlet loss area, and set up an end staggered section in the end bridging section, so that the same parallel branch changes the slot layer position in different stator slots, and the end bridging sections of different parallel branches are staggered in the near slot end area, the middle end area, and the outer end area.

[0009] S4, Fixed insulation forming: Insulation reinforcement, position fixation and impregnation forming are carried out on the straight section in the slot, the layered transposition section in the slot, the end staggered section and the branch connection section.

[0010] S5, Inspection, Correction and Storage: Perform DC resistance testing, branch potential consistency testing, end gap testing and insulation testing on each parallel branch. After passing the inspection, archive the loss area record table, phase band wiring table and fixed insulation forming record table.

[0011] The technical effects and advantages of this invention are as follows:

[0012] 1. This invention divides the stator slot into slot opening layer, slot middle layer, and slot bottom layer by locating the loss area and determining the phase band wiring. The first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are arranged according to the branch rotation allocation rule and reverse balance connection. This process allows the same parallel branch to pass through different slot layer positions within different pole pitch ranges, avoiding the long-term concentration of a single parallel branch in the slot opening loss area, weakening the continuous impact of slot opening leakage flux on a single branch, and reducing the induced potential difference and circulating current loss between each parallel branch.

[0013] 2. This invention uses the coordinated wiring of the in-slot layered transposition section and the end staggered section to enable the straight section in the slot to complete the layer adjustment in the end entrance loss area, and to make the end bridging section staggered in the near end area, middle end area and outer end area. This treatment reduces the additional loss and local heat generation caused by the adjacent arrangement of end conductors without changing the basic structure of the stator core and the main pitch of the winding. At the same time, it makes the influence of end leakage flux on different parallel branches more balanced, and improves the energy efficiency performance of the energy-saving starter motor for offshore wind turbine generators in the start-up and stable operation stages.

[0014] 3. This invention, through branch length compensation rules, transition insulation sheets, end isolation pads, branch marking sleeves, and inspection and correction warehousing processes, enables wiring improvements to be stably implemented in manufacturing. The branch length compensation rules control conductor length changes caused by end misalignment sections, reducing branch DC resistance differences. Transition insulation sheets and end isolation pads enhance the insulation reliability of the layered transposition sections and end misalignment sections within the slot. DC resistance detection, branch potential consistency detection, end gap detection, and insulation detection form a closed-loop correction, ensuring that the motor maintains stable winding position, stable insulation state, and stable branch connection state in humid, salt spray, and vibration environments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0016] Figure 2 This is a flowchart of the positioning loss area of ​​the present invention.

[0017] Figure 3 This is a flowchart illustrating the process of determining the phase band wiring according to the present invention.

[0018] Figure 4 This is a flowchart illustrating the process of setting up the transposition lead in this invention.

[0019] Figure 5 This is a flowchart of the detection, correction, and data entry process of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] refer to Figures 1-5 The method for reducing additional losses in the winding wiring of an offshore wind turbine, as shown, includes:

[0022] S1, Locating Loss Area: Before winding wiring, the stator slots, end areas, and parallel branch connection areas of the energy-saving starter motor for offshore wind turbines are divided to determine the locations where additional losses are likely to occur.

[0023] S1 first obtains the stator core data of the energy-saving starter motor for offshore wind turbine generators. The stator core data includes the number of stator slots, the width of the stator slots, the depth of the stator slots, the size of the stator slot opening, the effective length of the stator core, the winding pitch, the number of conductors per slot, and the number of parallel branches.

[0024] Each stator slot is divided into three layers along its depth: the slot opening layer, the slot middle layer, and the slot bottom layer. The slot opening layer is closer to the inner circle of the stator, the slot bottom layer is closer to the stator yoke, and the slot middle layer is located between the slot opening layer and the slot bottom layer. The division is based on the actual net height of the slot where conductors can be placed. The area in the slot where conductors can be placed is allocated according to the number of conductor layers. For a single-layer winding, the slot opening layer, slot middle layer, and slot bottom layer correspond to the relative positions of the same conductor group in different stator slots. For double-layer or multi-layer windings, the slot opening layer, slot middle layer, and slot bottom layer correspond to the actual radial arrangement position of the conductors in the slot.

[0025] After the division is completed, a stator slot layering record table is formed in the process record. The stator slot layering record table records the available slot opening layer position, slot middle layer position, and slot bottom layer position in each stator slot.

[0026] When determining the slot loss zone, the slot layer is the key area. During the starting phase, the energy-saving starter motor for offshore wind turbines has a large current and the magnetic field of the air gap between the rotor and stator changes significantly. The slot layer is close to the air gap and is easily affected by slot leakage magnetic field.

[0027] In existing wiring methods, conductors of the same parallel branch may be concentrated in the slot opening layer for a long time, causing the parallel branch to be subjected to stronger leakage magnetic cutting, resulting in inconsistent induced potentials between parallel branches. This method marks the slot opening layer of each stator slot as the slot opening loss zone and marks the end bend position adjacent to the slot opening layer as the end inlet loss zone.

[0028] When determining the end loss zone, the focus is on checking the concentration of the end bridging section, which is the part that forms a span connection on the outside of the stator end face after the coil leaves the stator slot.

[0029] The end bridging section is divided into a near-slot end area, a middle end area, and an outer end area. The near-slot end area is close to the stator slot outlet, the middle end area is located in the arc-shaped transition area of ​​the end bridging section, and the outer end area is close to the end binding ring.

[0030] When determining the branch connection loss zone, the branch connection sections of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are inspected. The branch connection section includes the connecting wires of each parallel branch in the same phase winding before they merge and the lead wires connected to the terminals. The branch connection section is divided into the connection area before the branch merge and the connection area before the terminals. The connection area before the branch merge is used for subsequent adjustment of the wire length of each parallel branch, and the connection area before the terminals is used for subsequent setting of the same routing direction and the same fixed spacing.

[0031] After the loss area is located, a loss area record table is formed, which includes at least the stator slot number, phase, slot opening layer occupancy status, slot middle layer occupancy status, slot bottom layer occupancy status, end inlet loss area location, end bridging section partition location, and branch connection loss area location. Production personnel mark the winding mold, winding tooling, or winding assembly drawing according to the loss area record table.

[0032] S1 first transforms the areas where additional losses are easily concentrated into operable wiring positions, and then designs the winding path. This process avoids adjusting the end shape based solely on experience and also avoids simply increasing the cross-sectional area of ​​the copper wire, so that each subsequent parallel branch can pass through the slot opening layer, the middle slot layer, and the bottom slot layer as planned, thereby providing a definite process basis for reducing additional losses.

[0033] S2, Determine the phase band wiring: After completing the positioning loss area, assign each phase band, each coil group, and each parallel branch of the main power winding accordingly, so that the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch obtain a similar electromagnetic environment within the same electrical angle range.

[0034] When S2 performs the determination of phase band wiring, it first establishes phase band numbering. The main power winding includes the U-phase main power winding, the V-phase main power winding, and the W-phase main power winding. Each phase main power winding is divided into several coil groups according to the pole phase group. The coil groups that appear sequentially along the circumferential direction in each phase are called the first coil group, the second coil group, the third coil group, and the fourth coil group, and continue to be numbered sequentially along the circumferential direction. The number of coil groups is determined by the motor slot pole matching.

[0035] After establishing the phase band numbering, the stator slot number corresponding to each coil group is determined. Each coil group has a first slot straight segment and a second slot straight segment. The first slot straight segment is located in the stator slot where the coil starts, and the second slot straight segment is located in the stator slot where the coil stops. The first slot straight segment and the second slot straight segment are connected by an end bridging segment. The original winding pitch is retained during wiring.

[0036] When allocating parallel branches, a branch rotation allocation rule is adopted, specifically: in the same phase main power winding, the first coil group is given priority to allocate the first parallel branch, the second coil group is given priority to allocate the second parallel branch, the third coil group is given priority to allocate the third parallel branch, and the fourth coil group is given priority to allocate the fourth parallel branch; when the actual number of parallel branches is less than four, the allocation is carried out cyclically according to the actual number of parallel branches; when the number of coil groups exceeds the number of parallel branches, the subsequent coil groups continue to be allocated cyclically in the order of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch.

[0037] S2 sets up a reverse balancing connection in the phase band wiring. The reverse balancing connection means that the parallel branches in two adjacent pole pitch ranges within the same phase main power winding enter the slot in opposite order. Within the first pole pitch range, the first parallel branch enters the slot opening layer first, the second parallel branch enters the slot middle layer first, the third parallel branch enters the slot bottom layer first, and the fourth parallel branch enters according to the remaining slot position. Within the second pole pitch range, the first parallel branch enters the slot bottom layer first, the second parallel branch enters the slot opening layer first, the third parallel branch enters the slot middle layer first, and the fourth parallel branch enters according to the remaining slot position. This reverse balancing connection allows each parallel branch to experience different slot depth positions within adjacent pole pitch ranges, reducing the continuous influence of a single slot depth position on the branch potential.

[0038] In the wiring file, each coil group is formed into a phase band wiring table, which records the coil group name, phase, parallel branch name, stator slot where the straight segment in the first slot is located, stator slot where the straight segment in the second slot is located, slot layer where the straight segment in the first slot is located, slot layer where the straight segment in the second slot is located, and end zone where the end bridging segment is located.

[0039] When determining the phase band wiring, the phase sequence of each phase main power winding is checked, including the spatial sequence check of the U-phase main power winding, V-phase main power winding, and W-phase main power winding, as well as the series-parallel relationship check of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch. During the check, the winding development diagram is used as the basis to mark the current direction of each coil group, confirming that the current direction of each coil group of the same phase main power winding is consistent in the same polarity region and opposite in the adjacent polarity regions.

[0040] When determining the initial position of the end bridging section, the end bridging section of the first parallel branch is preferentially arranged in the near-end area of ​​the tank, the end bridging section of the second parallel branch is preferentially arranged in the middle end area, the end bridging section of the third parallel branch is preferentially arranged in the outer end area, and the fourth parallel branch selects an empty path between the near-end area of ​​the tank and the middle end area. Within the adjacent pole distance range, the partitioning order of the end bridging sections is set in reverse.

[0041] S3, Set up transposition leads: According to the phase band wiring table, set up in-slot layer transposition sections and end staggered sections between the straight sections in the slot and the end bridging sections, so that the same parallel branch changes the slot layer position in different stator slots, and at the same time, the different parallel branches are staggered in the end area.

[0042] S3 first determines the coil groups that need to be swapped according to the phase band wiring table, including two types: the first type is the coil group that occupies the slot layer continuously for more than a preset number of times in the same parallel branch; the second type is the coil group with densely arranged end bridging sections in the same end partition. The preset number of times is determined in the process document according to the motor slot pole matching.

[0043] The in-slot layered transposition section is located at the end entrance of the stator slot. Specifically, before the straight section in the first slot enters the stator slot, the conductor layer adjustment is completed in the end entrance loss zone, so that the conductor after entering the stator slot can fall into the slot opening layer, slot middle layer, and slot bottom layer specified in the phase band wiring table. The conductor makes a smooth turn in the end entrance loss zone, and the turning radius is not less than three times the outer diameter of the conductor insulation to prevent the insulation layer from being damaged. For rectangular conductors, the width direction of the in-slot layered transposition section is kept consistent with the width direction of the straight section in the slot to reduce torsional stress.

[0044] When the first parallel branch occupies the slot layer in the first coil group, the first parallel branch is adjusted to the middle layer or bottom layer of the slot in the next adjacent transpositionable coil group. The second parallel branch is rotated according to the same rules, but the initial slot layer of the second parallel branch is staggered from that of the first parallel branch. The third and fourth parallel branches are executed according to the phase band wiring table. Each parallel branch undergoes at least one slot layer change after completing one pole pitch range. The slot layer change is completed in the layer transposition section within the slot. The straight section within the slot remains straight within the effective core length of the stator slot.

[0045] The end offset section is located in the middle of the end bridging section. The end offset section consists of an axial offset portion and a radial offset portion. The axial offset portion is used to make the end bridging section staggered front and back along the motor axis, and the radial offset portion is used to make the end bridging section staggered inside and outside along the stator radial direction. The end offset section of the first parallel branch is close to the stator slot outlet. The end offset section of the second parallel branch is located outside the first parallel branch. The end offset section of the third parallel branch is located outside the second parallel branch. The fourth parallel branch is arranged in adjacent empty positions according to the end space. Within the adjacent pole pitch range, the end offset sections of the first and second parallel branches are interchanged, and the end offset sections of the third and fourth parallel branches are interchanged, so that the additional end losses will not be concentrated in the same parallel branch for a long time.

[0046] When implementing the end-spacing section, the electrical length difference of the end-bridging section is kept under control. A branch length compensation rule is set in the end-spacing section. Specifically, when the length of the first parallel branch increases due to the end-spacing, the corresponding reserved length is reduced in the subsequent branch connection section of the same phase main power winding; when the length of the second parallel branch decreases due to the end-spacing, the corresponding reserved length is increased in the subsequent branch connection section of the same phase main power winding. The adjustment position is limited to the connection area before the branch convergence. During production, the compensation is completed through the bending path and end binding path of the branch connection section.

[0047] S3 sets in-slot layer transposition marks and end misalignment marks on the winding mold. The in-slot layer transposition marks are used to indicate that the conductor should enter the slot opening layer, slot middle layer, and slot bottom layer before entering the stator slot. The end misalignment marks are used to indicate that the end bridging section should be located in the near end area, middle end area, and outer end area. The winding worker winds the coil group according to the marks, and the coil embedding worker embeds the coil group into the corresponding stator slot according to the phase band wiring table. For pre-formed coils, in-slot layer transposition sections and end misalignment sections are formed on the pre-formed jig so that the coil has the required shape before being embedded into the stator slot.

[0048] When setting up the layered transposition section in the slot, control the insulation gap between conductors. Insulation pads are retained between the slot opening layer conductor and the slot wedge. Interlayer insulation is set between the middle layer conductors in the slot. Slot bottom insulation is set between the bottom layer conductor and the stator slot bottom. Due to the layer adjustment of the conductor at the layered transposition section in the slot, transition insulation sheets need to be added. The transition insulation sheets are attached to the conductor turning area. The length of the transition insulation sheet covers the entire transition range of the conductor from the original slot layer to the target slot layer. The edges of the transition insulation sheet are rounded to avoid cutting the conductor insulation in the vibration environment.

[0049] For energy-saving starter motors used in offshore wind turbines employing multi-strand parallel conductors, the relative positions of the multi-strand parallel conductors are synchronously adjusted in the layered transposition section within the slot. The multi-strand parallel conductors are first kept parallel on the winding mold, and then grouped and transposed at the layered transposition section within the slot. The adhesive paint or wrapping tape between the multi-strand parallel conductors is kept continuously covered. After the transposition is completed, an outer layer is wrapped to reduce adjacent losses between the multi-strand parallel conductors and maintain the consistency of branch manufacturing.

[0050] For energy-saving starter motors used in offshore wind turbines employing rectangular flat wires, the layered transposition section within the slot adopts a short-distance stepped transition. This short-distance stepped transition consists of a first straight section, a transition bend section, and a second straight section. The first straight section corresponds to the original slot layer, and the second straight section corresponds to the target slot layer. The transition bend section is located in the end inlet loss zone and does not enter the effective core range of the stator slot. The wide face of the rectangular flat wire maintains a consistent orientation within the transition bend section to avoid insulation cracks caused by torsion. For energy-saving starter motors used in offshore wind turbines employing round wires, the layered transposition section within the slot adopts a continuous arc transition. The maximum external dimension of the continuous arc transition must not interfere with the adjacent end bridging section.

[0051] Before binding the staggered end sections, pre-arrange the ends, placing the end bridging sections of each phase main power winding in the target end zone according to the phase wiring table, and checking the distance between adjacent end bridging sections. After the end pre-arrangement is completed, temporarily fix the staggered end sections of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch using heat-resistant binding tape or temporary clamps. After temporary fixation, check the routing direction of the branch lead-out sections to confirm that the branch lead-out sections will not compress the staggered end sections.

[0052] When arranging the branch lead-out sections, all branch lead-out sections lead to the connection area in front of the terminal block in the same direction. The branch lead-out sections of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are arranged in layers in the connection area in front of the terminal block. The order of the layer arrangement corresponds to the final position of the end staggered section.

[0053] S3 enables the main power winding of the energy-saving starter motor for offshore wind turbines to form a wiring structure with in-slot layered transposition sections and end staggered sections. This structure allows the same parallel branch to pass through different slot layers in the circumferential direction, and allows different parallel branches to be arranged in staggered arrangement at the ends, thereby controlling the length of the branch connection section.

[0054] S4, Fixed Insulation Forming: After the transposition leads are installed, the layered transposition sections, end staggered sections, straight sections, and branch connection sections in the trench are reinforced with insulation, fixed in position, and impregnated with varnish to form a stable wiring structure during the operation of the energy-saving starter motor for offshore wind turbine generators.

[0055] S4 first inspects the insulation inside the stator slot. In each stator slot, slot bottom insulation, interlayer insulation, and slot opening insulation are placed. The slot bottom insulation covers the contact area between the bottom layer of the slot and the bottom of the stator slot. The interlayer insulation covers the contact area between the slot opening layer, the middle layer of the slot, and the bottom layer of the slot. The slot opening insulation covers the contact area between the slot opening layer and the slot wedge. The layered transposition section inside the slot passes through the end inlet loss area. A transition insulation sheet is added at the end inlet loss area. The transition insulation sheet overlaps with the slot bottom insulation, interlayer insulation, and slot opening insulation. The overlap area is in contact with the outer surface of the conductor to avoid forming exposed edges.

[0056] After the straight section in the slot is embedded into the stator slot, the slot layer position of each parallel branch is confirmed according to the phase band wiring table. During confirmation, a slot layer inspection piece is used to gently push along the stator slot inlet to determine whether the conductor is located in the specified slot layer. The slot layer inspection piece is made of insulating material to prevent scratching the conductor insulation during the inspection process. When the straight section in the slot is inconsistent with the phase band wiring table, it is adjusted before impregnation. The adjustment is limited to the end inlet loss area and the stator slot end inlet position.

[0057] When fixing the staggered end section, first fix the near-groove end area, then fix the middle end area, and finally fix the outer end area. The near-groove end area is close to the stator slot outlet. After fixing, it restricts the springback of the layered transposition section in the slot. After fixing the middle end area, it can stabilize the main arc path of the end bridging section. After fixing the outer end area, it can stabilize the overall shape of the end. The binding strap is set in segments along the circumferential direction. Each segment of the binding strap covers the adjacent end bridging section and maintains the reserved gap between the staggered end sections.

[0058] When fixing the end offset section, an end isolation pad is set between the end offset section and the metal pressure plate. The end isolation pad is made of heat-resistant insulating material and is placed near the metal component of the end offset section. The end isolation pad is used to increase the insulation distance and reduce the local loss caused by end leakage magnetic field near the metal component. The installation position of the end isolation pad is recorded in the fixed insulation forming record table. The fixed insulation forming record table is used for inspection during subsequent maintenance.

[0059] When the branch connection section is fixed, the connection lengths of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are determined according to the branch length compensation rule. The end of the branch connection section near the terminal block adopts a layered lead-out method. The first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are kept in an identifiable state. After fixing, a branch identification sleeve is installed at each branch lead-out position, and the branch name is marked on the branch identification sleeve.

[0060] After fixing, impregnation molding is performed. Before impregnation, preheating is carried out to remove moisture inside the winding. The preheating temperature and time are in accordance with the process requirements of the insulation material. During impregnation, the insulating varnish is fully inserted into the gaps between the straight sections, the layered transposition sections, the end staggered sections, and the branch connection sections in the slot. For energy-saving starter motors used in offshore wind turbines, vacuum pressure impregnation process is preferred. The vacuum stage is used to remove gas inside the winding, and the pressure stage is used to promote the insulating varnish to enter the small gaps. After impregnation, curing is performed. The curing temperature and time are in accordance with the requirements of the insulating varnish material.

[0061] During the impregnation process, a temporary end support is retained before impregnation to prevent the end misalignment section from changing position due to the flow and curing shrinkage of the insulating varnish. The temporary end support is set outside the end misalignment section and does not block the insulating varnish from entering the conductor gap. After curing, the temporary end support is removed and it is checked whether the end misalignment section remains in the position recorded in the fixed insulation forming record sheet. The temporary end support is not used as a motor running part and is removed after impregnation curing.

[0062] When forming the layered transposition section in the slot, check the insulation filling status at the stator slot outlet. The conductor of the layered transposition section in the slot is adjusted from the slot layer into the end bridging section. After impregnation, visual inspection and insulation probe are used to check the stator slot outlet position to confirm that there are no obvious gaps, no insulation sheets are lifted, and no conductors are exposed. If it is found that the insulating varnish is not fully covered, touch-up varnish is applied before curing. The touch-up varnish area covers the outer surface of the layered transposition section in the slot and the edge of the insulation between adjacent layers.

[0063] After the end staggered section is formed, check the end external dimensions, including the end axial extension length, end radial outer diameter, end inner clearance, and branch lead-out section height. The end axial extension length must not interfere with the motor end cover, the end radial outer diameter must not interfere with the inner wall of the machine base, the end inner clearance must not interfere with the rotor assembly, and the branch lead-out section height must not interfere with the junction box assembly.

[0064] After the fixed insulation forming is completed, a fixed insulation forming record table is formed, including the position of the layered transposition section in the groove, the position of the end staggered section, the position of the transition insulation sheet, the position of the end isolation pad, the position of the branch identification sleeve, the impregnation batch, and the curing parameters. The fixed insulation forming record table, together with the loss area record table and the phase band wiring table, constitutes the production traceability document.

[0065] The S4 section provides specialized transition insulation sheets, end isolation pads, and temporary end supports at the layered transposition sections and end misalignment sections within the slot, ensuring the stable preservation of the spatial wiring structure. When the energy-saving starter motor for offshore wind turbines operates in vibration and humid environments, the layered transposition sections within the slot will not change their slot position due to rebound, the end misalignment sections will not re-close due to vibration, and the branch connection sections will not change their compensation length due to wiring operations.

[0066] S5, Inspection, Correction, and Storage: After the fixed insulation forming is completed, the winding electrical consistency, branch connection status, end misalignment status, and insulation status of the energy-saving starter motor for offshore wind turbine generators are inspected. Based on the inspection results, the branch connection sections or end misalignment sections are corrected. After the inspection is qualified, the loss area record table, phase wiring table, and fixed insulation forming record table are archived and stored.

[0067] S5 first performs a visual inspection, including whether the layered transposition section in the slot is located in the end inlet loss area, whether the end misalignment section is located in the corresponding end partition, whether the transition insulation sheet covers the conductor turning area, whether the end isolation pad is located between the end misalignment section and the metal part, and whether the branch marking sleeve is complete and clear. The visual inspection is based on the fixed insulation forming record sheet and is checked item by item. When the end misalignment sections are found to be close together, the position is recorded first, and then the end correction process is entered.

[0068] Subsequently, DC resistance testing was performed, measuring the resistance of each parallel branch within the U-phase main power winding, V-phase main power winding, and W-phase main power winding. The first, second, third, and fourth parallel branches were disconnected at their junctions before measurement to ensure that the measurement results reflected the actual resistance of each parallel branch. The winding temperature remained consistent during measurement, and the measurement results were converted to the same reference temperature. If the difference in DC resistance between the parallel branches exceeded the allowable range of the process, the length of the branch connection section and the crimping status of the joints were checked first.

[0069] When the DC resistance difference exceeds the allowable range of the process and the joint crimping condition is normal, the branch connection section is corrected. The correction of the branch connection section is performed in the connection area before the branch convergence. The correction method is to adjust the bending path of the branch connection section, so that the reserved bending length is increased for the branch connection section that is too short, and the reserved bending length is reduced for the branch connection section that is too long. After correction, the branch connection section is re-fixed and the DC resistance is tested again.

[0070] After the DC resistance test is qualified, the branch potential consistency test is performed. The branch potential consistency test is performed under low voltage rotation or power frequency induction. During the test, the rotor or external excitation conditions are kept stable. The induced potential of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch are measured respectively. The measurement results are used to determine whether the phase band wiring and transposition leads have achieved branch balance. If the induced potential of a certain parallel branch deviates from the process allowable range, the phase band wiring table is checked first, and then the actual tank layer position of the parallel branch in the tank layer transposition section is checked.

[0071] When the branch potential consistency test fails and there is a deviation in the tank layer position, the layer transposition section in the tank is adjusted before impregnation and curing. After impregnation and curing, the problem is improved by fine-tuning the branch connection section and correcting the end misalignment section. The fine-tuning of the branch connection section is used to adjust the branch resistance balance, and the end misalignment section correction is used to adjust the end proximity state. If the deviation comes from the wiring error, the branch lead section is reconnected, and the DC resistance test and branch potential consistency test are performed again.

[0072] Then, end gap detection is performed. The end gap detection checks the distance between the end misalignment sections, the fit between the end misalignment section and the end isolation pad, and the insulation distance between the end misalignment section and the metal parts of the base. The detection tool is an insulated feeler gauge or a special end gap gauge. If the end gap is unqualified, it is corrected in the end section where the end misalignment section is located. The correction method is to loosen the local binding tape, adjust the position of the end misalignment section, add end isolation pads or replace the binding points. After the correction is completed, it is re-bound and repainted.

[0073] After the end gap inspection is qualified, insulation resistance and withstand voltage tests are performed. The insulation resistance test is used to confirm the insulation status of the winding to the stator core, and the withstand voltage test is used to confirm that the winding insulation can withstand the specified test voltage. If the test results are qualified, they are recorded in the test correction and inventory record table. If the test results are unqualified, the fault area is located first, and then insulation repair or winding rework is carried out according to the fault area.

[0074] The S5 also requires a moisture-proof sealing inspection. The moisture-proof sealing inspection includes checking whether there are gaps not covered by insulating paint in the branch lead-out section, the connection area in front of the terminal block, and near the end isolation pad. If gaps are found, use insulating sealing material that matches the main insulation system to seal them. After sealing, perform insulation resistance testing again.

[0075] In the final stage of inspection, correction and warehousing, the loss area record sheet, phase band wiring sheet, fixed insulation forming record sheet and inspection, correction and warehousing record sheet are archived. The archived content includes stator number, motor number, winding batch, coil group number, parallel branch name, slot layer transposition section position, end misalignment section position, inspection data and correction record. After archiving, the energy-saving starter motor for offshore wind turbine generators enters the finished product warehousing or whole machine assembly process.

[0076] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0077] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reducing additional losses in the winding wiring of an offshore wind turbine, characterized in that, include: S1, Locating the loss zone: Divide the stator slot along the slot depth direction into slot opening layer, slot middle layer, and slot bottom layer. Mark the slot opening layer as slot opening loss zone. Mark the stator slot end inlet position as end inlet loss zone. Divide the area where the end bridging section is located into near slot end zone, middle end zone, and outer end zone, and form a loss zone record table. S2, Determine the phase band wiring: Establish a phase band wiring table based on the loss area record table, divide the main power winding into U-phase main power winding, V-phase main power winding and W-phase main power winding, and assign the coil group in each phase main power winding to the first parallel branch, the second parallel branch, the third parallel branch and the fourth parallel branch accordingly. S3, Set up transposition leads: According to the phase band wiring table, set up a layered transposition section in the slot in the end inlet loss area, and set up an end staggered section in the end bridging section, so that the same parallel branch changes the slot layer position in different stator slots, and the end bridging sections of different parallel branches are staggered in the near slot end area, the middle end area, and the outer end area. S4, Fixed insulation forming: Insulation reinforcement, position fixation and impregnation forming are carried out on the straight section in the slot, the layered transposition section in the slot, the end staggered section and the branch connection section. S5, Inspection, Correction and Storage: Perform DC resistance testing, branch potential consistency testing, end gap testing and insulation testing on each parallel branch. After passing the inspection, archive the loss area record table, phase band wiring table and fixed insulation forming record table.

2. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In step S1, the loss zone record table includes stator slot number, phase, slot opening layer occupancy status, slot middle layer occupancy status, slot bottom layer occupancy status, end inlet loss zone location, end bridging section partition location, and branch connection loss zone location. The branch connection loss zone includes the connection zone before branch convergence and the connection zone before terminal block.

3. The method for reducing additional losses in the winding wiring of an offshore wind turbine according to claim 1, characterized in that, In step S2, each phase main power winding is divided into a first coil group, a second coil group, a third coil group, and a fourth coil group according to the circumferential direction, and is further numbered in the circumferential direction. Each coil group includes a straight segment in the first slot, a straight segment in the second slot, and an end bridging segment. The straight segment in the first slot is located in the stator slot where the starting edge of the coil is located, and the straight segment in the second slot is located in the stator slot where the ending edge of the coil is located.

4. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In step S2, a branch rotation allocation rule is adopted. The first coil group is allocated the first parallel branch, the second coil group is allocated the second parallel branch, the third coil group is allocated the third parallel branch, and the fourth coil group is allocated the fourth parallel branch. Subsequent coil groups are allocated in a cyclical manner according to the order of the first parallel branch, the second parallel branch, the third parallel branch, and the fourth parallel branch, so that the parallel branches are staggered along the circumference of the stator.

5. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In step S2, a reverse balance connection is set. Within the first pole distance range, the first parallel branch enters the slot opening layer, the second parallel branch enters the middle layer of the slot, and the third parallel branch enters the bottom layer of the slot. Within the second pole distance range, the first parallel branch enters the bottom layer of the slot, the second parallel branch enters the slot opening layer, and the third parallel branch enters the middle layer of the slot, so that the same parallel branch passes through different slot layer positions within adjacent pole distance ranges.

6. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In step S3, the in-slot layered transposition section is set in the end inlet loss zone outside the effective core length range of the stator slot. The in-slot layered transposition section allows the same parallel branch to pass through the slot opening layer, the middle layer, and the bottom layer in sequence within a mechanical circumference, and ensures that the same parallel branch occupies the slot opening layer no more than twice consecutively.

7. The method for reducing additional losses in the winding wiring of an offshore wind turbine according to claim 1, characterized in that, In step S3, the end offset section includes an axial offset portion and a radial offset portion. The axial offset portion causes the end bridging sections of different parallel branches to be offset along the motor axial direction, and the radial offset portion causes the end bridging sections of different parallel branches to be offset along the stator radial direction. The end offset sections of the first parallel branch and the second parallel branch within the adjacent pole pitch range are interchanged, and the end offset sections of the third parallel branch and the fourth parallel branch are interchanged.

8. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In step S3, a branch length compensation rule is set. When the conductor length of any parallel branch increases due to the end misalignment section, the reserved bending length of the parallel branch is reduced in the connection area before the branches of the main power winding in the same phase merge. When the conductor length of any parallel branch is reduced due to the end offset section, the reserved bending length of the parallel branch is increased in the connection area before the branches of the main power winding of the same phase merge, so that the DC resistance difference of each parallel branch meets the requirements of the product process document.

9. The method for reducing additional losses in the windings of an offshore wind turbine according to claim 1, characterized in that, In steps S4 and S5, a transition insulating sheet is set in the layered transposition section in the groove, an end isolation pad is set between the end staggered section and the metal component, and a branch identification sleeve is set in the branch lead-out section. When the DC resistance test fails, the branch connection section is corrected in the connection area before the branch convergence; when the end gap test fails, the position of the end misalignment section is corrected and re-fixed; when the insulation test fails, the insulation of the layered transposition section, end misalignment section and branch connection section in the slot is repaired.

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