Front-end speed regulating device of wind generating set

Abstract

The technical scheme relates to the technical field of wind power generation, in particular to a front-end speed regulation device of a wind generating set, when the front-end speed regulation device works, an input shaft transmits power to a first-stage planetary gear mechanism, and the first-stage planetary gear mechanism distributes the power to a generator and a second-stage planetary gear mechanism; the second-stage planetary gear mechanism distributes received power to the fixed shaft gear set and the hydraulic torque converter, the hydraulic torque converter transmits the power to the fixed shaft gear set, and the fixed shaft gear set conveys the received power back to the first-stage planetary gear mechanism. Through the cooperation of the first-stage planetary gear mechanism and the second-stage planetary gear mechanism and the combination of the hydraulic torque converter, the scheme of power division and power backflow is achieved, energy loss can be reduced during working, and the overall transmission efficiency can also be guaranteed in the low-rotating-speed state.

Description

TECHNICAL FIELD

[0001] The technical scheme relates to the field of wind power generation, in particular to a front-end speed regulating device of a wind turbine generator system. BACKGROUND

[0002] In the field of wind power generation, in order to ensure stable grid-connected power generation, the varying rotational speed of a wind wheel needs to be converted into a constant rotational speed of a generator. As a kind of stepless speed regulating scheme, the hydraulic planetary speed regulating technology has the advantages of low cost, compact structure and high power generation quality compared with electronic frequency converters, and therefore has a good application prospect in the field of wind power generation.

[0003] The technology usually adopts a structure combining a hydraulic torque converter and a planetary gear, and realizes accurate regulation of the output rotational speed by adjusting the guide vane opening of the hydraulic torque converter and controlling the differential speed of the planetary gear.

[0004] However, with the development of wind turbine generators towards large-scale and deep-sea, the single-machine power is continuously improved, and extreme working conditions frequently occur, which puts forward higher requirements on the power generation efficiency, speed regulating range and operation reliability of the transmission system. The existing part of the hydraulic planetary speed regulating device has problems such as low efficiency at low speed, complex structure and limited adaptability, which restricts the reliable application of the hydraulic planetary speed regulating device in large-power wind turbine generators. SUMMARY

[0005] The technical scheme aims to provide a front-end speed regulating device for a wind turbine generator system, which realizes the scheme of power splitting and power backflow through the cooperation of a first-stage planetary gear mechanism and a second-stage planetary gear mechanism in combination with a hydraulic torque converter, and solves the problem of low transmission efficiency of the existing technology at low rotational speed.

[0006] The technical scheme is achieved in the following manner: A front-end speed regulating device for a wind turbine generator system for variable speed control of an offshore large-power generator set, comprising: an input shaft, a first-stage planetary gear mechanism, a second-stage planetary gear mechanism, a hydraulic torque converter and a fixed shaft gear set; The input shaft is connected to the first-stage planetary gear mechanism, the first-stage planetary gear mechanism is connected to a generator and the second-stage planetary gear mechanism, the second-stage planetary gear mechanism is connected to the hydraulic torque converter, the hydraulic torque converter is connected to the fixed shaft gear set, and the fixed shaft gear set is connected to the first-stage planetary gear mechanism and the second-stage planetary gear mechanism; In operation, the input shaft transmits power to the first-stage planetary gear mechanism, the first-stage planetary gear mechanism distributes the power to the generator and the second-stage planetary gear mechanism, the second-stage planetary gear mechanism distributes the received power to the fixed shaft gear set and the hydraulic torque converter, the hydraulic torque converter transmits the power to the fixed shaft gear set, and the fixed shaft gear set re-transmits the received power back to the first-stage planetary gear mechanism.

[0007] Preferably, the hydraulic torque converter comprises a pump wheel, a primary turbine, a primary guide wheel, a secondary turbine and an adjustable guide wheel; the primary guide wheel is mounted on the shell between the primary turbine and the secondary turbine, and the secondary guide wheel is located between the pump wheel and the secondary turbine; In operation, the liquid enters the primary turbine from the pump wheel, and then enters the pump wheel again via the primary guide wheel, the secondary turbine and the secondary guide wheel to form a liquid flow circulation.

[0008] Preferably, the hydraulic torque converter has a turbine torque output shaft, and an overrunning clutch is connected to the turbine torque output shaft, and the overrunning clutch is connected to the first-stage planetary gear mechanism.

[0009] Preferably, the pump wheel, the primary turbine, the primary guide wheel, the secondary turbine and the adjustable guide wheel are sequentially arranged to form a five-working-wheel structure.

[0010] Preferably, the primary turbine and the secondary turbine independently operate and are connected to the turbine torque output shaft through a fixed shaft gear set and an overrunning clutch, respectively. In the first working condition, the overrunning clutch is wedged, and the primary turbine and the secondary turbine jointly output torque. In the second working condition, the overrunning clutch is disengaged, the primary turbine idles, and only the secondary turbine works.

[0011] Preferably, the overrunning clutch is an inner cam roller type overrunning clutch, the inner ring is a cylindrical surface, the outer ring is a cam surface, and the roller is arranged between the inner and outer rings.

[0012] The technical scheme has the following prominent and beneficial technical effects compared with the prior art: 1. The first-stage planetary gear mechanism and the second-stage planetary gear mechanism in the technical scheme realize the structure of power split and power return, transmit the main kinetic energy to the generator, distribute a small part of the energy to the hydraulic torque converter, use the cooperation of the hydraulic torque converter and the fixed shaft gear set to adjust the speed, reduce the energy loss, and ensure the overall transmission efficiency in a low speed state.

[0013] 2. The hydraulic torque converter realizes automatic optimization of the working mode through the cooperation of the double turbine structure and the overrunning clutch. In the first working condition (low speed ratio working condition), the overrunning clutch is wedged to make the primary turbine and the secondary turbine work in series, significantly increase the system torque ratio, and improve the starting and low speed running capability; in the second working condition (high speed ratio working condition), the overrunning clutch is automatically disengaged, the primary turbine idles and exits the work, and only the secondary turbine in the high efficiency area transmits the power, thereby reducing the hydraulic loss. The design expands the high efficiency working range of the hydraulic torque converter, enables the hydraulic torque converter to maintain a high transmission efficiency when the wind wheel speed changes in a large range, and effectively adapts to the complex operating environment of the offshore wind turbine generator with variable load. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 It is the front end speed regulating device structure principle diagram of the technical scheme.

[0015] Fig. 2 It is the power flow schematic diagram of the front end speed regulating device of the technical scheme.

[0016] Fig. 3 It is the structure schematic diagram of the hydraulic torque converter circulation circle and the overrunning clutch cooperation of the technical scheme.

[0017] Reference signs: 1, first stage planetary gear mechanism planet carrier; 2, first stage planetary gear mechanism sun gear; 3, gear ring one; 4, fixed shaft gear one; 5, fixed shaft gear two; 6, torque output shaft; 7, hydraulic torque converter; 8, fixed shaft gear three; 9, gear ring two; 10, second stage planetary gear mechanism planet carrier; 11, second stage planetary gear mechanism sun gear; 12, fixed shaft gear four; 13, gear one; 14, gear two; 15, gear three; 16, gear four; B, pump wheel; T1, first stage turbine; D1, first stage guide wheel; T2, second stage turbine; D2, adjustable guide wheel. DETAILED DESCRIPTION

[0018] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0019] As Figs. 1-3 shown, a front end speed regulating device of a wind turbine generator set is suitable for offshore low-speed high-power wind turbine generator set, comprising: an input shaft, a first stage planetary gear mechanism, a second stage planetary gear mechanism, a hydraulic torque converter 7 and a fixed shaft gear set; the input shaft is connected with the first stage planetary gear mechanism, the first stage planetary gear mechanism is connected with a generator and the second stage planetary gear mechanism, the second stage planetary gear mechanism is connected with the hydraulic torque converter 7, the hydraulic torque converter 7 is connected with the fixed shaft gear set, and the fixed shaft gear set is connected with the first stage planetary gear mechanism and the second stage planetary gear mechanism.

[0020] When working, the input shaft transmits power to the first stage planetary gear mechanism, the first stage planetary gear mechanism distributes power to the generator and the second stage planetary gear mechanism, the second stage planetary gear mechanism distributes the received power to the fixed shaft gear set and the hydraulic torque converter 7, the hydraulic torque converter 7 transmits power to the fixed shaft gear set, and the fixed shaft gear set transmits the received power back to the first stage planetary gear mechanism; the fixed shaft gear set comprises a fixed shaft gear one 4, a fixed shaft gear two 5, a fixed shaft gear three 8 and a fixed shaft gear four 12.

[0021] The input shaft receives the rotating shaft speed (about 300-500 rpm) of a wind wheel after speed increasing through a variable speed gear box, and transmits the stable rotating speed output by the front end speed regulating device to the generator (1500 rpm).

[0022] The input shaft is connected with the output end of the transmission gear box, the input shaft is connected with the first stage planetary gear mechanism planet carrier 1, the first stage planetary gear mechanism sun gear is connected with the second stage planetary gear mechanism planet carrier 10 and the generator; the ring gear one 3 of the first stage planetary gear mechanism is connected with the fixed shaft gear one 4, the torque output shaft 6 with the overrunning clutch is connected with the fixed shaft gear two 5, the fixed shaft gear one 4 and the fixed shaft gear two 5 are meshed with each other. At the same time, the fixed shaft gear four 12 is coaxially arranged with the fixed shaft gear one 4, the fixed shaft gear four 12 is connected with the second stage planetary gear mechanism sun gear 11, the second stage planetary gear mechanism planet carrier 10 is connected with the generator, and the ring gear two 9 of the second stage planetary gear mechanism is connected with the fixed shaft gear three 8.

[0023] The pump wheel B of the hydraulic torque converter 7 is connected with the fixed shaft gear three 8, the turbine of the hydraulic torque converter 7 is connected with the torque output shaft 6 with the overrunning clutch, and the turbine torque output shaft 6 is connected with the fixed shaft gear two 5.

[0024] The turbine of the hydraulic torque converter 7 is connected with the turbine torque output shaft 6 through the overrunning clutch, and a double-turbine independent rotation structure is formed. When working, the input power is branched through the first stage planetary gear mechanism, most of the power is transmitted to the generator through a mechanical path, and a small part of the power drives the hydraulic torque converter 7 through the second stage planetary gear mechanism, and after being adjusted by the hydraulic torque converter 7, it is returned to the ring gear of the first stage planetary gear mechanism through the fixed shaft gear set, forming a transmission path combined with power branching and power returning, and maintaining high transmission efficiency during speed regulation.

[0025] The device uses two groups of planetary gear mechanisms to realize the composite structure of power branching and power returning, allocates most of the energy to the efficient mechanical gear transmission, and allocates a small part of the energy to the hydraulic torque converter 7 for speed regulation, which can reduce a large amount of energy loss. In order to improve the working efficiency of the hydraulic torque converter 7, it is designed as a double-turbine independent rotation structure, and the turbine torque is output through the fixed shaft gear and the overrunning clutch. Compared with the rigid connection mode of the two turbines, the overrunning clutch can automatically adjust the working state of the turbine according to the speed ratio, connect the two turbines in series to increase the torque ratio at low speed, and disconnect the first turbine to reduce energy loss at high speed, so as to maintain a high overall transmission efficiency in a wide range of load changes.

[0026] As Fig. 2The power flow direction when the front end speed regulating device works is shown. The traditional backflow scheme is to install the pump wheel B of the hydraulic torque converter 7 on the output shaft, the turbine transmits power to the outer gear ring of the first stage planetary gear mechanism, and then the power is combined with the input of the first stage planetary gear mechanism carrier 1 and is output to the sun gear of the first stage planetary gear mechanism, forming a power circulation. The difference of the scheme is that the second stage planetary gear mechanism is added, a part of the backflow power is distributed to the gear transmission, and the other part is distributed to the hydraulic torque converter 7, and finally the power is combined at the gear ring 1 of the first stage planetary gear mechanism, so that the absorption power of the pump wheel B of the hydraulic torque converter 7 is reduced, the backflow power is branched, and the efficiency of the device is further improved. Assuming that the friction loss of the gear transmission is ignored, the speed-torque relationship between the first stage planetary gear mechanisms satisfies:

[0027] Wherein, n: speed, (n1: planetary carrier speed, n2: sun gear speed, n3: gear ring one speed); Parameter a1: gear number ratio of gear ring one and sun gear; T: torque, (T1: planetary carrier torque, T2: sun gear torque, T3: gear ring one torque); The speed-torque relationship between the second stage planetary gear mechanisms satisfies:

[0028] Wherein, n: speed, (n 10 : planetary carrier speed, n 11 : sun gear speed, n9: gear ring two speed); Parameter a2: gear number ratio of gear ring two and sun gear; T: torque, (T 10 : planetary carrier torque, T 11 : sun gear torque, T9: gear ring two torque); Supposing that the efficiency of the hydraulic torque converter is , and the torque ratio is , then the relationship between the input and output torque of the hydraulic torque converter and the gear transmission ratio is:

[0029] Wherein, n: speed, (n5: fixed shaft gear two, n8: fixed shaft gear three, n T : speed of the turbine in the hydraulic torque converter, n B : speed of the pump wheel in the hydraulic torque converter); According to the gear transmission ratio relationship of the fixed shaft gear set, there is

[0030] Wherein, n: rotation speed, (n2: rotation speed of the sun gear of the first stage planetary gear mechanism, n3: rotation speed of the ring gear one, n4: rotation speed of the fixed shaft gear one, n5: rotation speed of the fixed shaft gear two, n8: rotation speed of the fixed shaft gear three, n9: rotation speed of the ring gear two, n 10 : rotation speed of the planet carrier of the second stage planetary gear mechanism, n 11 : rotation speed of the sun gear of the second stage planetary gear mechanism, n 12 : rotation speed of the fixed shaft gear four); System input and output power

[0031] The above formula can be obtained by integrating the pump wheel absorption power ratio of the hydraulic torque converter to the total input power:

[0032] Therefore, the pump wheel absorption power ratio can be further reduced by increasing the torque ratio of the hydraulic torque converter, and the speed regulation range of the hydraulic torque converter can be adjusted according to the transmission ratio of the fixed shaft gear connected by the pump wheel turbine.

[0033] Here, the hydraulic torque converter 7 is a variable speed input and variable speed output, that is, a mapping relationship between the input speed and the output speed needs to be established to maintain a constant output speed, and the turbine speed is always less than the pump wheel B speed during speed regulation. According to the input speed and by adjusting the guide wheel opening of the hydraulic torque converter 7, the turbine torque shaft speed output is controlled to achieve the expected output speed.

[0034] The hydraulic torque converter 7 uses a double-turbine guide vane adjustable hydraulic torque converter 7 with an overrunning clutch. As Fig. 3 shown, the hydraulic torque converter 7 adopts a five working wheel structure, that is, in the form of B-T-D-T-D, including a pump wheel B, a first stage turbine T1, a first stage guide wheel D1, a second stage turbine T2 and an adjustable guide wheel D2. The first stage guide wheel D1 is fixedly installed on the shell between the first stage turbine T1 and the second stage turbine T2, and the second stage guide wheel is located between the pump wheel B and the second stage turbine T2. In operation, the liquid enters the first stage turbine T1 from the pump wheel B, passes through the first stage guide wheel D1, the second stage turbine T2 and the second stage guide wheel, and then enters the pump wheel B to form a liquid flow circulation.

[0035] The difference between the ordinary guide vane adjustable hydraulic torque converter 7 is that the first turbine T1 and the second turbine T2 are independently operated and connected to the turbine torque output shaft 6 through the fixed shaft gear and the overrunning clutch, the first turbine T1 is connected to the second level planetary gear mechanism through gear three 15, gear four 16 and the overrunning clutch, and the second level planetary gear mechanism is connected to the second ring gear 9, when the gear four 16 speed is lower than the gear two 14, the overrunning clutch will be connected to the gear four 16 and the gear two 14 shaft, and the torque of the first turbine T1 is transmitted to the torque output shaft 6, when the speed of the gear four 16 is higher than that of the gear two 14, the gear four 16 and the gear two 14 are separated, and the first turbine T1 is idle and out of work. The second turbine T2 is in working state in the whole speed ratio range.

[0036] At low speed, the second turbine T2 and the second turbine T2 mainly participate in work, the speed of the first turbine T1 is increased, the liquid flow out of the first turbine T1 rushes to the working surface of the blade of the second turbine T2, and the liquid flow generates positive torque to the second turbine T2. In the low speed ratio range, the two turbines work together to output power, the torque of the second turbine T2 is gradually increased, and the torque of the first turbine T1 is gradually decreased.

[0037] When the speed of the first turbine T1 reaches the speed at which the liquid flow at the outlet of the pump wheel B is deflected from the working surface to the back surface, the torque of the first turbine T1 changes from positive to negative, and due to the action of the overrunning clutch, it is separated from the output shaft, the first turbine T1 rotates freely and exits the work, only the second turbine T2 works. At the same time, the inner cam roller type overrunning clutch is adopted, the inner ring is designed as a cylindrical surface, the deformation of the cylindrical surface will not cause significant change of the locking angle, so the wear failure of the overrunning clutch in the locked state can be reduced, and the cam surface is located on the outer ring, when the overrunning clutch is in the separated state, the outer ring has the same speed as the roller, so the outer ring does not produce wear, at the same time, due to the reduced speed of the roller relative to the previous speed, the centrifugal force of the roller is also greatly reduced, which can improve the service life of the overrunning clutch.

[0038] The hydraulic torque converter 7 can automatically switch the working mode of the two turbines according to the working condition, and work in series at low speed to realize high torque ratio, and the overrunning clutch separates at high speed to make the first turbine T1 idle to reduce energy loss, thereby improving the efficiency, and the transmission efficiency can be kept high in a wide speed ratio range, which is suitable for the complex and variable operating environment of offshore wind turbine.

[0039] At the same time, the dependence on multiple hydraulic torque converters 7 and complex gear structures is reduced, the overall structure is compact, and it is suitable for offshore wind power platforms with limited space. At the same time, the overrunning clutch adopts the inner cam roller type design, which has small wear and long service life, and further improves the operation reliability of the system.

[0040] In summary, the device not only realizes higher energy utilization rate, but also widens the high-efficiency working interval and effectively reduces the energy loss under the part-load working condition. Meanwhile, the optimized power cycle structure enhances the adaptability to the high-power load and guarantees the stability and reliability under the high-power density operation, thereby being particularly suitable for the high-power power generation scene such as large wind turbine generators.

[0041] The front-end speed regulating device in the technical solution can be implemented in the following manner: The input shaft receives the rotational speed (about 300-500 rpm) of the wind wheel after the speed-up through the gear box; The power split and backflow are realized through the two-stage planetary gear structure, and the hydraulic torque converter 7 only bears a small part of the speed regulating power; the hydraulic torque converter 7 of the double turbine automatically switches the working mode through the overrunning clutch, the double turbine is connected in series to improve the torque ratio at low speed, and only the second turbine T2 works at high speed to improve the efficiency; the output shaft outputs a constant rotational speed (1500 rpm) to the generator to realize grid-connected power generation. The device can monitor the wind speed and rotational speed signals in real time through the numerical control system, adjust the guide vane opening of the hydraulic torque converter 7, and realize automatic speed regulation.

Claims

1. A front-end speed regulating device for a wind turbine generator set, used for speed control of high-power offshore generator sets, characterized in that, include: Input shaft, first-stage planetary gear mechanism, second-stage planetary gear mechanism, hydraulic torque converter (7) and fixed-axis gear set; The input shaft is connected to the first stage planetary gear mechanism, the first stage planetary gear mechanism is connected to the generator and the second stage planetary gear mechanism, the second stage planetary gear mechanism is connected to the hydraulic torque converter (7), the hydraulic torque converter (7) is connected to the fixed-axis gear set, and the fixed-axis gear set is connected to the first stage planetary gear mechanism and the second stage planetary gear mechanism. During operation, the input shaft transmits power to the first-stage planetary gear mechanism, which distributes the power to the generator and the second-stage planetary gear mechanism. The second-stage planetary gear mechanism distributes the received power to the fixed-axis gear set and the hydraulic torque converter (7). The hydraulic torque converter (7) transmits the power to the fixed-axis gear set, which then transmits the received power back to the first-stage planetary gear mechanism.

2. The front-end speed regulating device for wind turbine generator sets according to claim 1, characterized in that: The hydraulic torque converter (7) includes a pump impeller (B), a first-stage turbine (T1), a first-stage guide wheel (D1), a second-stage turbine (T2), and an adjustable guide wheel (D2); the first-stage guide wheel (D1) is installed on the housing between the first-stage turbine (T1) and the second-stage turbine (T2), and the second-stage guide wheel is located between the pump impeller (B) and the second-stage turbine (T2); During operation, the liquid enters the first-stage turbine (T1) from the pump wheel (B), and then enters the pump wheel (B) again via the first-stage guide wheel (D1), the second-stage turbine (T2), and the second-stage guide wheel to form a liquid flow circulation.

3. The front-end speed regulating device for wind turbine generator sets according to claim 2, characterized in that: The hydraulic torque converter (7) has a turbine torque output shaft (6) connected to an overrunning clutch, which is connected to the first-stage planetary gear mechanism.

4. The front-end speed regulating device for wind turbine generator sets according to claim 3, characterized in that: The pump wheel (B), the first-stage turbine (T1), the first-stage guide wheel (D1), the second-stage turbine (T2), and the adjustable guide wheel (D2) are arranged in sequence to form a five-wheel structure.

5. The front-end speed regulating device for a wind turbine generator set according to claim 2 or 4, characterized in that: The first-stage turbine (T1) and the second-stage turbine (T2) operate independently and are connected to the turbine torque output shaft (6) via a fixed-axis gear set and an overrunning clutch, respectively. Under the first operating condition, the overrunning clutch is engaged, and the first-stage turbine (T1) and the second-stage turbine (T2) jointly output torque; In the second operating condition, the overrunning clutch disengages, the first-stage turbine (T1) idles, and only the second-stage turbine (T2) operates.

6. The front-end speed regulating device for a wind turbine generator set according to claim 5, characterized in that: The overrunning clutch is an internal cam roller type overrunning clutch, with its inner ring being a cylindrical surface and its outer ring being a cam surface, and rollers positioned between the inner and outer rings.

7. The front-end speed regulating device for wind turbine generator sets according to claim 5, characterized in that: The speed-torque relationship between the first-stage planetary gear mechanism is as follows: The speed-torque relationship between the second-stage planetary gear mechanisms is as follows: Assume the efficiency of the hydraulic torque converter is The torque ratio is Then the relationship between the input and output torques of the hydraulic torque converter and the gear ratio is: Based on the transmission ratio relationship of the fixed-axis gear set, we have System input and output power Combining the above formulas, we can obtain the ratio of the pump impeller power absorbed by the hydraulic torque converter to the total input power: 。

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