A vertical axis wind turbine and a variable pitch driving system thereof

Abstract

The application discloses a vertical shaft wind turbine generator set and a variable pitch driving system thereof, which comprises a main controller PLC, a variable pitch power distribution cabinet, a variable pitch cabinet, peripheral sensors and three variable pitch motors. The variable pitch cabinet is internally provided with a rectifier module and three drivers in communication connection with the main controller PLC. The peripheral sensors are electrically connected with the acquisition ends of the three drivers. The three drivers are powered by the variable pitch power distribution cabinet. The three-phase output terminals of the three drivers are respectively connected with the three-phase windings of the three variable pitch motors. The input end of the rectifier module is connected with a power module in the variable pitch power distribution cabinet through a variable pitch slip ring. The output end of the rectifier module is electrically connected with the DC input ends of the three drivers through a common DC bus. The variable pitch power distribution cabinet is installed in a cabin. The variable pitch cabinet is installed in a hub. Each variable pitch motor and its corresponding variable pitch transmission are installed at a corresponding blade. The application can improve the anti-vibration performance of the power supply, reduce energy impact and reduce cost.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation equipment, specifically relating to a vertical axis wind turbine generator set and its pitch drive system. Background Technology

[0002] Vertical axis wind turbines (VAT turbines) have demonstrated enormous application potential due to their unique advantages, such as no need for yaw control, low operating noise, convenient maintenance, and adaptability to complex and variable wind directions. However, traditional lift-type Darrieus VAT turbines suffer from three major bottlenecks: low aerodynamic efficiency, poor self-starting capability, and large cyclic loads. Research shows that active pitch control technology, by adjusting the blade pitch angle in real time, can improve wind energy capture efficiency, effectively suppress cyclic loads, and achieve reliable self-starting and overspeed protection. To suppress cyclic loads, mainstream approaches include dividing the 360° circumference into upwind, downwind, or multi-azimuth intervals; the system has independent pitch control functionality, with different optimal pitch angles set for the three blades in different azimuth intervals; and the pitch angle command is calculated based on wind speed, tip speed ratio, and rotor azimuth angle and sent to the actuator to dynamically adjust the pitch angle per revolution.

[0003] The existing pitch drive system of vertical axis wind turbine generators has the following problems:

[0004] (1) The pitch distribution cabinet, pitch cabinet and three pitch motors are all placed inside the hub. The power module inside the pitch distribution cabinet will rotate with the hub, resulting in poor vibration resistance.

[0005] (2) Since the wind turbine is divided into windward zone, transition zone and leeward zone in 360°, at the same time, the three blades may be in the windward zone, transition zone and leeward zone respectively. The wind load direction of the three blades is different. In order to maintain the target position of the blades, the three pitch motors will be in different working states. For example, the first pitch motor is in the driving power consumption mode, while the second and third pitch motors are in the braking power generation mode, which will cause energy impact problems. Summary of the Invention

[0006] The purpose of this invention is to provide a vertical axis wind turbine generator and its pitch drive system to improve the vibration resistance of the power supply, reduce energy impact, and reduce costs.

[0007] In a first aspect, the present invention provides a pitch drive system for a vertical axis wind turbine generator, comprising a main controller PLC, a pitch distribution cabinet, a pitch control unit, peripheral sensors, and three pitch motors. The pitch control unit contains three drivers communicatively connected to the main controller PLC. The peripheral sensors are electrically connected to the acquisition terminals of the three drivers. The pitch distribution cabinet supplies power to the three drivers, and the three-phase output terminals of the three drivers are respectively connected to the three-phase windings of the three pitch motors. The pitch control unit also contains a rectifier module. The input terminal of the rectifier module is connected to the power module within the pitch distribution cabinet via a pitch slip ring, and the output terminal of the rectifier module is electrically connected to the DC input terminals of the three drivers via a common DC bus. The pitch distribution cabinet is installed in the nacelle, the pitch control unit is installed in the hub, and each pitch motor and its corresponding pitch gearbox are installed on a corresponding blade.

[0008] The pitch control unit houses a rectifier module and connects the DC input terminals of the three drives in parallel via a common DC bus, enabling energy sharing and feedback within the drive system. During pitch control, when a blade experiences a negative load due to wind speed changes, the corresponding pitch motor operates in braking and power generation mode. The generated electrical energy is fed back to the common DC bus to directly supply other pitch motors operating in drive power consumption mode, rather than being consumed by the braking resistor. This not only reduces the energy consumption of the pitch drive system itself but also reduces bus voltage fluctuations (i.e., reduces energy surges). The pitch control unit is located in the nacelle, the pitch control cabinet is located in the hub, and the pitch motor is located at the blade root. The power module is housed in the nacelle and does not rotate with the hub, significantly reducing the centrifugal force and vibration experienced by the power supply, improving its vibration resistance, and enhancing the reliability of the wind turbine generator under high-speed conditions.

[0009] Optionally, the rectifier module includes a rectifier unit, a braking unit, and a three-phase circuit breaker. One end of the three-phase circuit breaker is connected to the pitch slip ring, and the other end is electrically connected to the three-phase AC input terminal of the rectifier unit. The voltage discharge terminal of the rectifier unit is electrically connected to the voltage input terminal of the braking unit. The DC output terminal of the rectifier unit is electrically connected to the DC input terminals of the three drives via a common DC bus. When a serious fault such as a short circuit, overload, or insulation breakdown occurs in the pitch control unit inside the hub, the three-phase circuit breaker can instantly trip mechanically, taking priority over the protection action of the pitch distribution cabinet in the engine compartment at the front end of the pitch slip ring, accurately isolating the fault point on the hub side. During operation, the electrical energy generated by the braking generator of the pitch motor in braking power generation mode is preferentially used by the pitch motor in drive power consumption mode. When the electrical energy generated by braking is excessive and the bus voltage exceeds a set threshold, the rectifier unit opens the braking unit to discharge excess electrical energy (which is consumed by the braking resistor in the braking unit). Compared to a scheme where each driver is equipped with a single braking unit, the scheme using a shared DC bus significantly reduces the heat generation of the braking unit and the entire drive system, as well as lowers the rated power of the braking unit, reduces the number of braking units, and thus reduces costs.

[0010] Optionally, the rectifier module further includes a three-phase reactor and a three-phase filter. The three-phase reactor and the three-phase filter are connected in series and are integrated between the three-phase circuit breaker and the three-phase AC input terminal of the rectifier unit. Through the series arrangement of the three-phase reactor and the three-phase filter at the AC input terminal, the dual functions of high-order harmonic suppression and transient energy dissipation are simultaneously achieved at the physical level. This provides a clean, low-impedance, high-quality AC power supply environment for the subsequent rectifier unit, significantly improving the operational robustness and electromagnetic compatibility of the pitch drive system under harsh power grid conditions.

[0011] Optionally, the pitch control cabinet includes a main power supply circuit and a backup power supply. The main power supply circuit includes a Dynamic Voltage Restorer (DVR) and an Uninterruptible Power Supply (UPS). The three-phase AC input of the DVR is connected to the power grid, and its three-phase AC output is electrically connected to the three-phase AC input of the UPS. The three-phase AC output of the UPS is connected to the pitch slip rings, and the backup power supply is externally connected to the battery port of the UPS. The coordinated control of the DVR and UPS enables high-voltage ride-through, low-voltage ride-through, and feathering functions during power outages. When the grid voltage is normal, the DVR operates in bypass mode, and the grid supplies power directly. When the grid voltage is abnormal, the DVR quickly responds to compensate for the voltage. When the grid fails, the UPS immediately switches power supply with a switching time ≤5ms, ensuring continuous operation of the pitch drive system and meeting the voltage ride-through requirements for wind power grid connection, thus improving system-level power supply reliability.

[0012] Optionally, the dynamic voltage restorer (DVR) is model DVR-400 / 3-100, with a compensation voltage range of 0-130%Un, a response time ≤2ms, and a compensation time ≥3s, which can accurately suppress overvoltage within 400VAC±2%. The uninterruptible power supply (UPS) is model Schneider SPM10KL-33, with a rated power of 10kVA, and the external battery (i.e., backup power supply) capacity supports three feathering operations, achieving seamless power supply during grid outages.

[0013] Optionally, the pitch slip ring is a contact slip ring, which has a first set of power rings and a second set of power rings (i.e., a redundant design). The first and second sets of power rings are used in parallel, and the three-phase loops in the two sets of power rings are separated by the PE and N loops in the two sets of power rings. Electrically connecting the two sets of power rings in parallel to the same power supply circuit allows them to share the current load under normal operating conditions, effectively reducing the temperature rise effect caused by the accumulation of contact resistance in a single loop and slowing down the oxidation rate of the friction pair. When one set of power rings experiences poor contact or open circuit due to long-term rotational wear, surface electrolytic corrosion, or instantaneous overcurrent, the other set of parallel loops can seamlessly take over the entire current load without stopping the machine for switching. This avoids the risk of emergency feathering failure of the pitch system due to single-point failure of the slip ring and improves system reliability. The PE and N loops act as natural electric field shielding layers, avoiding the possibility of mutual interference between the three-phase loops in the two sets of power rings.

[0014] Optionally, the contact slip ring has ten power channels, which are respectively the L1 channel SR:1 of the first group of power rings, the L2 channel SR:2 of the first group of power rings, the L3 channel SR:3 of the first group of power rings, the PE channel SR:4 of the first group of power rings, the PE channel SR:5 of the second group of power rings, the N channel SR:6 of the first group of power rings, the N channel SR:7 of the second group of power rings, the L3 channel SR:8 of the second group of power rings, the L2 channel SR:9 of the second group of power rings, and the L1 channel SR:10 of the second group of power rings. By constructing a mirror-symmetrical channel distribution on the circumference of the contact slip ring, the normal pressure and friction force experienced by the brush during rotational contact are centrally symmetrically distributed along the axial direction, effectively eliminating the off-center load torque caused by unidirectional sequential arrangement and avoiding excessive local wear of the contact surface between the brush and the channel.

[0015] Optionally, the pitch slip ring includes a slip ring frame, a slip ring spindle located within the slip ring frame, and ten conductive rings fitted onto the slip ring spindle and rotating with it. Adjacent conductive rings are separated by insulating spacers fitted onto the slip ring spindle and rotating with it. Two conductive rings located at the ends of the slip ring spindle are also separated from the ends of the slip ring frame by the insulating spacers, forming the ten power loops. The outer diameter of the insulating spacer is larger than the outer diameter of the conductive ring, and there is a gap between the insulating spacer and the slip ring frame. By providing insulating spacers with larger outer diameters between adjacent conductive rings and between the end conductive rings and the end of the frame, the creepage distance between adjacent high-voltage power loops is effectively extended. When two sets of parallel power loops generate arcing due to instantaneous overcurrent, the insulating spacer acts as a physical barrier to effectively break and extinguish the arc, preventing the arc from spreading axially to adjacent loops, thereby enhancing the pitch slip ring's arc-extinguishing capability and tolerance level under short-circuit fault conditions. By pre-reserving an annular gap between the outer edge of the insulating spacer and the inner wall of the frame, a channel for removing and collecting dust particles generated by the long-term rotational friction of the brush is provided, preventing wear powder from accumulating at the edge of the spacer to form a conductive layer or aggravating electrolytic corrosion of the insulation surface. At the same time, this gap allows the slip ring spindle to generate a small amount of axial thermal displacement and radial vibration offset under the centrifugal force generated by the pitching action and the effect of thermal expansion and contraction, preventing interference collisions or jamming between the insulating spacer and the inner wall of the frame, and eliminating the risk of spacer breakage caused by mechanical stress concentration.

[0016] Optionally, the peripheral sensors include three rotor azimuth encoders and three limit switches. The three rotor azimuth encoders are electrically connected to the rotor azimuth acquisition terminals of the three drivers, respectively. The three limit switches are installed at the extreme positions of the three blades and are connected to the limit signal acquisition terminals of the three drivers. By configuring and hard-wire-connecting the rotor azimuth encoders to each driver independently, three physically isolated blade pitch angle closed-loop adjustment channels are constructed. This effectively avoids control lag and phase deviation caused by bus communication delays or main controller scan cycle jitter, enabling the three blades to perform highly synchronous independent pitch control actions based on their real-time detected rotor rotation positions. This precisely suppresses the in-plane load imbalance of the rotor, improving the overall power generation efficiency and operational stability. The limit switch signals at the mechanical limit positions are directly connected to the ports of the corresponding drivers. When the blade rotates to the mechanical stop limit, the trigger signal of the limit switch can be directly latched into the internal logic of the driver in microseconds, effectively avoiding the risk of mechanical jamming and blade collision caused by software malfunction or communication interruption.

[0017] In a second aspect, the present invention provides a vertical axis wind turbine generator set, which includes the pitch drive system of the above-mentioned vertical axis wind turbine generator set. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the pitch drive system of a vertical axis wind turbine generator set in an embodiment of the present invention.

[0019] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0020] Figure 3 for Figure 1 Sectional view of section BB in the image.

[0021] Figure 4 for Figure 3 A magnified view of point C in the middle.

[0022] Figure 5 This is a block diagram illustrating the control principle of the pitch drive system of a vertical axis wind turbine generator in an embodiment of the present invention.

[0023] Figure 6 This is a power distribution topology diagram of the pitch drive system of a vertical axis wind turbine generator in an embodiment of the present invention.

[0024] Figure 7 This is a schematic diagram of the structure of the pitch slip ring in an embodiment of the present invention.

[0025] Figure 8 This is a schematic diagram of the arrangement of ten power loops in an embodiment of the present invention. Detailed Implementation

[0026] To gain a more detailed understanding of the features and technical content of the embodiments of the present invention, the implementation of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention.

[0028] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0029] like Figures 1 to 8As shown, the pitch drive system of the vertical axis wind turbine generator in this embodiment of the invention includes a main controller PLC 6, a pitch distribution cabinet 1, a pitch control cabinet 2, a pitch slip ring 3, peripheral sensors 4, and three pitch motors 5. The pitch control cabinet 2 is installed inside the hub 8 and contains a rectifier module 22 and three drivers 21 that are communicatively connected to the main controller PLC 6. The peripheral sensors 4 are electrically connected to the acquisition terminals of the three drivers 21. The pitch distribution cabinet 1 is installed inside the nacelle 7. The input terminal of the rectifier module 22 is connected to the power module inside the pitch distribution cabinet 1 via the pitch slip ring 3, and the output terminal of the rectifier module 22 is electrically connected to the DC input terminals of the three drivers 21 via a common DC bus. The pitch distribution cabinet 1 supplies power to the three drivers 21. The three-phase output terminals of the three drivers 21 are respectively connected to the three-phase windings of the three pitch motors 5. Each pitch motor 5 and its corresponding pitch gearbox 10 are installed at a corresponding blade 9. As an example, the three-phase output terminals of the three drivers 21 are connected to the three-phase windings of the three pitch motors 5 via high-temperature resistant and vibration-resistant cables.

[0030] In some embodiments, the rectifier module 22 includes a rectifier unit 221, a braking unit 222, a three-phase circuit breaker 223, a three-phase reactor 224, and a three-phase filter 225. The three-phase circuit breaker 223, the three-phase reactor 224, and the three-phase filter 225 are connected in series as a whole. One end of this whole (i.e., one end of the three-phase circuit breaker 223) is connected to the pitch slip ring 3. The other end of the whole three-phase circuit breaker 223 (i.e., one end of the three-phase filter 225) is electrically connected to the three-phase AC input terminal of the rectifier unit 221. The voltage discharge terminal of the rectifier unit 221 is electrically connected to the voltage input terminal of the braking unit 222. The DC output terminal of the rectifier unit 221 is electrically connected to the DC input terminals of the three drivers 21 through a common DC bus.

[0031] During operation, the electrical energy generated by the braking generator of the pitch motor in braking power generation mode is fed back to the common DC bus and directly supplied to other pitch motors in drive power consumption mode. When the electrical energy generated by braking is too high and the bus voltage exceeds the set threshold, the rectifier unit will turn on the braking unit to release the excess electrical energy (the braking resistor in the braking unit consumes the electrical energy).

[0032] In some embodiments, the pitch control cabinet 1 includes a main power supply circuit 11 and a backup power supply 12. The main power supply circuit 11 includes a dynamic voltage restorer (DVR) and an uninterruptible power supply (UPS). The three-phase AC input of the DVR is connected to the power grid, and the three-phase AC output of the DVR is electrically connected to the three-phase AC input of the UPS. The three-phase AC output of the UPS is connected to the pitch slip ring 3, and the battery port of the UPS is connected to the backup power supply 12. As an example, the 400VAC main power supply circuit of the nacelle is connected to the pitch control cabinet 2 via the DVR, the UPS, and the pitch slip ring 3. The DVR and the UPS work together to achieve high voltage ride-through, low voltage ride-through, and feathering functions in the event of a power outage. When the grid voltage is normal, the Dynamic Voltage Restorer (DVR) operates in bypass mode and is directly powered by the grid. When the grid voltage is abnormal, the DVR responds quickly to compensate for the voltage. When the grid fails, the Uninterruptible Power Supply (UPS) immediately switches to power supply with a switching time of ≤5ms, ensuring the continuous operation of the pitch drive system.

[0033] In some embodiments, the dynamic voltage restorer (DVR) used is model DVR-400 / 3-100, with a compensation voltage range of 0-130%Un, a response time of ≤2ms, and a compensation time of ≥3s, which can accurately suppress overvoltage within 400VAC±2%.

[0034] In some embodiments, the uninterruptible power supply (UPS) is a Schneider SPM10KL-33 model with a rated power of 10kVA. The external battery capacity supports the requirement of three feathering operations and is connected to the DVR output to achieve seamless power supply when the grid fails.

[0035] In some embodiments, the pitch slip ring 3 is a contact slip ring, which has a first set of power rings and a second set of power rings (i.e., a redundant design). The first set of power rings and the second set of power rings are used in parallel, and the three-phase loops in the two sets of power rings are separated by the PE loop and the N loop in the two sets of power rings.

[0036] In some embodiments, the pitch slip ring 3 has ten power loop channels, which are respectively the L1 loop SR:1 of the first power loop, the L2 loop SR:2 of the first power loop, the L3 loop SR:3 of the first power loop, the PE loop SR:4 of the first power loop, the PE loop SR:5 of the second power loop, the N loop SR:6 of the first power loop, the N loop SR:7 of the second power loop, the L3 loop SR:8 of the second power loop, the L2 loop SR:9 of the second power loop, and the L1 loop SR:10 of the second power loop.

[0037] In some embodiments, the pitch slip ring 3 includes a slip ring frame 31, a slip ring main shaft 32 located within the slip ring frame 31, and ten conductive rings 33 that are fitted onto the slip ring main shaft 32 and rotate with it. Adjacent conductive rings 33 are separated by insulating spacers 34 that are fitted onto the slip ring main shaft 32 and rotate with it. Two conductive rings 33 located at the ends of the slip ring main shaft 32 are also separated from the ends of the slip ring frame 31 by insulating spacers 34 (a total of 11 insulating spacers), forming ten power loops 35. The outer diameter of the insulating spacers 34 is larger than the outer diameter of the conductive rings 33, and there is a gap between the insulating spacers 34 and the slip ring frame 31. As an example, the insulating spacers 34 are ceramic sheets.

[0038] In some embodiments, the peripheral sensor 4 includes three rotor azimuth encoders 41 and three limit switches 42. The three rotor azimuth encoders 41 are electrically connected to the rotor azimuth acquisition terminals of the three drivers 21, respectively. The three limit switches 42 are installed at the extreme positions of the three blades 9 and are connected to the limit signal acquisition terminals of the three drivers 21, respectively. As an example, the limit switches are connected to the drivers 21 in the form of DI signals. When the limit switch 42 is triggered, the driver output is stopped, thus protecting the blade extreme angle. The rotor azimuth encoders 41 are incremental encoders that feed back analog signals to the drivers. After being decoded and processed by the drivers, the signals are converted into azimuth values ​​and then transmitted to the main controller PLC 6 for control.

[0039] The pitch motor 5 acts as the actuator, outputting torque and speed, and has a built-in encoder to detect its position and angle. The pitch motor 5 primarily feeds back signals such as blade angle, motor current, motor torque, and motor speed to the driver.

[0040] Before the wind turbine generator set is put into operation, the azimuth angle of the wind turbine is zeroed to mark the mechanical zero position of the wind turbine. Three wind turbine azimuth angle encoders can detect three values ​​corresponding to the three blades when the wind turbine is in the mechanical zero position, which is convenient for subsequent calculation of the pitch angle. The pitch motor is also zeroed to mark the pitch angle zero position. When the wind turbine generator set is running, the wind turbine azimuth angle encoder 41 feeds back the detected analog signal to the driver 21. The driver 21 decodes and calculates it into a wind turbine azimuth angle value. The driver 21 uploads the wind turbine azimuth angle value to the main controller PLC 6. The main controller PLC 6 calculates the wind zone where the three blades are located by combining the wind speed and the wind turbine azimuth angle, and calculates the corresponding optimal pitch angle according to the preset algorithm. The optimal pitch angle of the three blades is sent down to the three drivers 21. After receiving the optimal pitch angle, the three drivers 21 control the corresponding pitch motor 5 to run to the optimal pitch angle. Because the three drivers 21 control the three pitch motors 5, and the three pitch motors 5 drive the three blades 9, and the driving of the three blades 9 is independent of each other, it is possible to achieve different pitch angles of the three blades at the same time, thereby performing independent pitch control.

[0041] In addition, this invention also provides a vertical axis wind turbine generator set, which includes the above-mentioned pitch drive system.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A pitch drive system for a vertical axis wind turbine generator set, comprising a main controller PLC (6), a pitch distribution cabinet (1), a pitch control cabinet (2), peripheral sensors (4), and three pitch motors (5), wherein the pitch control cabinet (2) has three drivers (21) that are communicatively connected to the main controller PLC (6), the peripheral sensors (4) are electrically connected to the acquisition terminals of the three drivers (21), the pitch distribution cabinet (1) supplies power to the three drivers (21), and the three-phase output terminals of the three drivers (21) are respectively connected to the three-phase windings of the three pitch motors (5); characterized in that: The pitch control cabinet (2) also has a rectifier module (22). The input end of the rectifier module (22) is connected to the power module in the pitch control cabinet (1) through the pitch slip ring (3). The output end of the rectifier module (22) is electrically connected to the DC input end of the three drivers (21) through the common DC bus. The pitch control cabinet (1) is installed in the nacelle (7), the pitch control cabinet (2) is installed in the hub (8), and each pitch motor (5) and its corresponding pitch gearbox (10) are installed on the corresponding blade (9).

2. The pitch drive system for a vertical axis wind turbine generator according to claim 1, characterized in that: The rectifier module (22) includes a rectifier unit (221), a braking unit (222), and a three-phase circuit breaker (223). One end of the three-phase circuit breaker (223) is connected to the pitch slip ring (3), and the other end of the three-phase circuit breaker (223) is electrically connected to the three-phase AC input terminal of the rectifier unit (221). The voltage discharge terminal of the rectifier unit (221) is electrically connected to the voltage input terminal of the braking unit (222), and the DC output terminal of the rectifier unit (221) is electrically connected to the DC input terminal of the three drivers (21) through a common DC bus.

3. The pitch drive system for a vertical axis wind turbine generator according to claim 2, characterized in that: The rectifier module (22) also includes a three-phase reactor (224) and a three-phase filter (225). The three-phase reactor (224) and the three-phase filter (225) are connected in series and are connected as a whole between the three-phase circuit breaker (223) and the three-phase AC input terminal of the rectifier unit (221).

4. The pitch drive system for a vertical axis wind turbine generator according to claim 1, characterized in that: The pitch control cabinet (1) has a main power supply circuit (11) and a backup power supply (12). The main power supply circuit (11) includes a dynamic voltage restorer (DVR) and an uninterruptible power supply (UPS). The three-phase AC input terminal of the dynamic voltage restorer (DVR) is connected to the power grid. The three-phase AC output terminal of the dynamic voltage restorer (DVR) is electrically connected to the three-phase AC input terminal of the uninterruptible power supply (UPS). The three-phase AC output terminal of the uninterruptible power supply (UPS) is connected to the pitch slip ring (3). The battery port of the uninterruptible power supply (UPS) is externally connected to the backup power supply (12).

5. The pitch drive system for a vertical axis wind turbine generator according to claim 4, characterized in that: The dynamic voltage restorer (DVR) is model DVR-400 / 3-100, and the uninterruptible power supply (UPS) is model Schneider SPM10KL-33.

6. The pitch drive system for a vertical axis wind turbine generator according to claim 1, characterized in that: The pitch slip ring (3) is a contact slip ring. The contact slip ring has a first set of power rings and a second set of power rings. The first set of power rings and the second set of power rings are used in parallel. The three-phase loops in the two sets of power rings are separated by the PE loop and the N loop in the two sets of power rings.

7. The pitch drive system for a vertical axis wind turbine generator according to claim 6, characterized in that: The contact slip ring has ten power ring channels, which are: L1 channel SR:1 of the first group of power rings, L2 channel SR:2 of the first group of power rings, L3 channel SR:3 of the first group of power rings, PE channel SR:4 of the first group of power rings, PE channel SR:5 of the second group of power rings, N channel SR:6 of the first group of power rings, N channel SR:7 of the second group of power rings, L3 channel SR:8 of the second group of power rings, L2 channel SR:9 of the second group of power rings, and L1 channel SR:10 of the second group of power rings.

8. The pitch drive system for a vertical axis wind turbine generator according to claim 7, characterized in that: The pitch slip ring (3) includes a slip ring frame (31), a slip ring main shaft (32) located within the slip ring frame, and ten conductive rings (33) that are sleeved on the slip ring main shaft (32) and rotate with the slip ring main shaft (32). Adjacent conductive rings (33) are separated by insulating spacers (34) that are sleeved on the slip ring main shaft (32) and rotate with the slip ring main shaft (32). The two conductive rings (33) located at the ends of the slip ring main shaft are also separated from the ends of the slip ring frame by the insulating spacers (34), forming the ten power ring channels. The outer diameter of the insulating spacers (34) is larger than the outer diameter of the conductive rings (33), and there is a gap between the insulating spacers (34) and the slip ring frame (31).

9. The pitch drive system for a vertical axis wind turbine generator according to any one of claims 1 to 7, characterized in that: The peripheral sensor (4) includes three wind turbine azimuth encoders (41) and three limit switches (42); the three wind turbine azimuth encoders (41) are electrically connected to the wind turbine azimuth acquisition terminals of the three drivers (21); the three limit switches (42) are installed at the extreme positions of the three blades and are connected to the limit signal acquisition terminals of the three drivers (21).

10. A vertical axis wind turbine generator set, characterized in that: Includes the pitch drive system as described in any one of claims 1 to 9.

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