A wind source simulation experimental device and control method for comprehensive energy in a park

Abstract

The present invention relates to a wind source simulation experimental device and control method for comprehensive energy in a park, which belongs to the field of experimental research equipment, and specifically relates to a wind source simulation experimental device for comprehensive energy research in a park. It is characterized in that: an asynchronous traction motor is arranged in the cabin, one end of the asynchronous traction motor is connected to a doubly fed wind generator through a rigid coupling, the other end of the asynchronous traction motor is connected to a gearbox, the other end of the gearbox is connected to a low-speed shaft through a support bearing, and the low-speed shaft is connected to a hub; a torque sensor is arranged between the asynchronous traction motor and the doubly fed wind generator; a yaw gear is arranged between the cabin and the tower, and the yaw gear is meshed with a yaw motor gear arranged in the cabin. The purpose of the present invention is to solve the problems that the wind turbine simulation experiment cannot be close to the real environment, the experimental cost is too high, and it is not economically reasonable.

Description

Technical Field

[0001] The invention belongs to the field of experimental research equipment, and in particular relates to a wind source simulation experimental equipment used for comprehensive energy research in a park. Background Art

[0002] With the development of social economy, modern society is increasingly dependent on energy. Traditional petrochemical energy such as oil and coal brings environmental pollution, so the country vigorously develops clean energy. Wind power generation occupies an important position in clean energy, but there are few test equipment for simulating wind turbines for wind power generation in the laboratory. The reason is that the wind turbine simulation experiment in the existing technology cannot be close to the real environment, and the experimental effect is different from the real unit; in addition, the experimental cost is too high and it is not economically reasonable; especially for wind source simulation experimental equipment used for comprehensive energy research in the park (miniaturization), there is still a blank. Summary of the invention

[0003] Purpose of the invention: The present invention provides a wind source simulation experimental equipment for comprehensive energy research in the park, which aims to solve the problems that the wind turbine simulation experiment cannot be close to the real environment, the experimental cost is too high, and it is not economically reasonable.

[0004] Technical solution:

[0005] A wind source simulation experiment equipment for comprehensive energy in a park, comprising a nacelle arranged on a tower, a hub arranged at the front end of the nacelle, and blades arranged on the hub, characterized in that: an asynchronous traction motor is arranged in the nacelle, one end of the asynchronous traction motor is connected to a double-fed wind generator through a rigid coupling, the other end of the asynchronous traction motor is connected to a gearbox, the other end of the gearbox is connected to a low-speed shaft through a support bearing, and the low-speed shaft is connected to the hub; a torque sensor is arranged between the asynchronous traction motor and the double-fed wind generator;

[0006] A yaw gear is provided between the nacelle and the tower, and the yaw gear is meshed with a yaw motor gear arranged in the nacelle.

[0007] A brake disc (16) and a brake (15) are arranged between the gearbox and the asynchronous traction motor, and the brake disc (16) and the brake (15) are fixed by a brake disc bracket (14).

[0008] There are three blades, which are connected to the hub at intervals of 120 degrees through a single screw drive structure, and a pitch mechanism is arranged between the blades and the hub.

[0009] The support bearings are a first support bearing and a second support bearing, which are respectively arranged on both sides of the low-speed shaft.

[0010] The cabin is a semi-open cabin.

[0011] A control method for a wind source simulation experimental device for comprehensive energy in a park as described above is characterized in that: the control method modulates the grid-connected process through a frequency converter, measures and reads voltage and current parameters, feeds back the conditions of both sides of the stator and rotor and the generator to the frequency converter, modulates the DC bus voltage, and when the parameters meet the grid-connected conditions, issues a grid-connected instruction and connects to the grid in real time; when the generator is in a subsynchronous state, the stator outputs energy and sends it to the grid; when the generator is in a synchronous state, the stator and rotor simultaneously supply power to the grid; according to the grid's requirements for wind farm crossing, the voltage protection limit is modified.

[0012] Low Voltage Ride Through:

[0013] It is divided into three stages:

[0014] 1) From the time the voltage drops below 90% of the rated voltage, the voltage does not drop below 20% of the rated voltage within 640ms, and the voltage detection module does not report a fault;

[0015] 2) From 640ms to 3s after the start of low voltage ride-through, the voltage rises to 90% of the rated voltage, and the voltage detection module does not report a fault;

[0016] 3) After 3s, low voltage ride-through is completed and the voltage should be maintained above 90% of the rated voltage;

[0017] Low voltage ride-through: Grid low voltage detection mainly relies on the low voltage ride-through state start signal sent by the inverter as the control starting point; when the inverter detects a grid voltage drop, its control mode is converted to the grid support mode; through the change of the status bit of the inverter to the main control, the main control system confirms that it is a low voltage ride-through state; after the grid voltage returns to the original value, the low voltage ride-through mode is turned off, and the active power increases to the set value at a ramp rate of 100ms, that is, from zero to rated power;

[0018] High voltage ride through: During the period of high voltage in the power grid, the inductive reactive power is absorbed through the converter control; during the period of high voltage in the power grid, the grid-side converter of the doubly fed wind turbine is in the rectification state of absorbing active and inductive reactive power from the power grid, or in the inversion state of transmitting active power to the power grid and absorbing inductive reactive power from the power grid, depending on the speed; the rotor-side converter needs to work in the inversion state of transmitting active power to the power grid and absorbing inductive reactive power from the power grid; after receiving the grid voltage increase fault signal from the converter, the main control system needs to shield some faults related to high voltage ride through, give up the power control right of the main control system, and set a reasonable grid high voltage ride through protection curve. During the period of high voltage ride through, the active and reactive power output of the wind turbine is determined by the converter control. After receiving the grid voltage recovery signal from the converter, the main control system restores the previously shielded fault or alarm signal, restores the control right over the wind turbine power, and realizes the normal operation and power generation of the wind turbine.

[0019] The present invention has the following advantages and positive effects:

[0020] In order to overcome the problems in the prior art that wind turbine simulation experiments cannot approach the real environment, the experimental results are different from the real units, and the experimental costs are too high and not economical, the present invention provides a wind source simulation device, so that the prime mover has the ability to simulate the output power (torque)-speed characteristics of the wind turbine, and the experimental unit can reproduce the dynamic process of the actual unit under the real environment. Therefore, this wind turbine model and its simulation control system not only inherit the advantages of low cost of the experimental bench, fast construction speed and high-power simulation, but also have flexible and changeable parameters, and the parameter matching relationship of different wind turbines, generators, gears and loads can be adjusted in the software to improve the research and use efficiency. In addition, under such experimental conditions, the experimental simulation of mechanical parts and electrical equipment such as generators and power converters is closer to the actual situation, and the quality of the wind turbines in the park are inspected and supervised, forming a complete system of technical management before wind turbines are connected to the grid, wind turbine safety supervision, wind power grid evaluation and inspection, so that photovoltaic and wind power generation in the park can be quickly switched between the two modes of grid-connected power generation and independent operation, thereby ensuring the quality and continuity of power supply to the relevant sensitive loads of the entire park. The experimental device is miniaturized and suitable for comprehensive energy research in the park, filling the gap of lack of experimental equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the main structure of the wind turbine generator set of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a simulation control system of a wind turbine generator set of the present invention;

[0023] Figure 1 Medium torque sensor 1, rigid coupling 2, doubly fed wind turbine 3, nacelle seat 4, yaw gear 5, tower 6, blade 7, pitch mechanism 8, hub 9, second support bearing 10, low-speed shaft 11, first support bearing 12, gearbox 13, brake disc bracket 14, brake 15, brake disc 16, yaw motor 17, asynchronous traction motor 18. DETAILED DESCRIPTION

[0024] The present invention is achieved through the following technical solutions: Figure 1 As shown:

[0025] A wind source simulation experiment device for comprehensive energy in a park is provided in a semi-open cabin for easy experimental operation. An asynchronous traction motor 18 is provided in the cabin, one end of the asynchronous traction motor 18 is connected to a double-fed wind generator 3 through a rigid coupling 2, the other end of the asynchronous traction motor 18 is connected to a gearbox 13, the other end of the gearbox 13 is connected to a low-speed shaft 11 through a support bearing, and the low-speed shaft 11 is connected to a wheel hub 9; a torque sensor 1 is provided between the asynchronous traction motor 18 and the double-fed wind generator 3.

[0026] The blades 7 are simulated blades. Three simulated blades are installed on the hub 9 at an interval of 120 degrees with a single screw drive structure. A low-speed shaft 11 is connected between the hub 9 and the gearbox 13. The low-speed shaft 11 is supported by a first support bearing 12 and a second support bearing 10. A brake disc 16 and a brake 15 are arranged behind the gearbox 13. The brake disc 16 is coaxial with the asynchronous traction motor 18, and a torque sensor 1 is installed behind the asynchronous traction motor 18. The double-fed wind turbine generator 3 is connected to the front shaft through a rigid coupling 2. A yaw motor 17 is arranged inside the cabin, and the gear of the yaw motor 17 is meshed with the yaw gear 5 on the top of the tower; a control cabinet and an operating table are connected outside the wind turbine model; a small wind measuring device is built outdoors, which is connected to the above-mentioned wind turbine model through a communication line as a wind measuring system of the wind source simulation experimental equipment; the above-mentioned experimental equipment can perform actual wind speed operation and simulated wind speed operation, and can be connected to the grid when the power generation parameters meet the grid connection conditions, and has high voltage ride-through and low voltage ride-through capabilities.

[0027] [Example 1]

[0028] Hub 9: Hub 9 fixes the blades and blade groups to the rotating shaft. It transmits the force and torque of the wind wheel to the main transmission mechanism. Hub 9 adopts a spherical structure and is made of ordinary carbon steel. Hub 9 is connected to the low-speed shaft 11 through a flange and connected to the blades 7 through the pitch mechanism 8.

[0029] Gearbox 13: simulates the speed increasing gearbox. According to the overall layout requirements of the unit, the low-speed shaft 11 directly connected to the wind wheel hub 9 is sometimes integrated with the input shaft of the gearbox, and its shaft end is in the form of a flange connection structure. The low-speed shaft 11 and the gearbox can also be arranged separately, and a structure of expansion sleeve or coupling connection is adopted between them.

[0030] Low-speed shaft 11 and coupling: Low-speed shaft 11 is installed between the wind wheel and the gearbox. The front end is rigidly connected to the hub 9 by bolts, and the rear end is connected to the gearbox (gearbox 13) at a low speed. The high-speed shaft of the gearbox and the input shaft of the generator are connected by a flexible coupling, which can compensate for the installation error of the transmission system, has large torque transmission, small size, good fatigue resistance and high reliability.

[0031] Doubly-fed wind turbine generator 3: adopts wound rotor induction generator. The generator stator is connected to the grid through the grid-connected switch, and the rotor is connected to the grid through the four-quadrant converter. During the variable speed operation of the unit, the generator speed changes with the change of wind speed, and the converter adjusts the rotor excitation to ensure constant frequency and constant voltage output on the stator side. Under synchronous speed, the rotor excitation inputs power and the stator side outputs power; above synchronous speed, both the rotor and stator sides output power.

[0032] Cabin demonstration: The cabin contains the hub, main shaft, transmission chain and cabin cabinet, etc. The position simulates the cabin control cabinet and demonstrates the actual unit status during operation.

[0033] Tower, chassis: The function of the nacelle chassis is to provide support for the device.

[0034] [Example 2]

[0035] The system consists of a yaw system, a pitch system, a transmission system, and a power generation system. Figure 2 shown.

[0036] Active yaw system: The yaw system consists of a yaw bearing, a yaw motor, a yaw reducer, and a yaw brake mechanism. It can realize functions such as yaw to wind and automatic unwinding. The unit measures the actual wind direction through the wind direction sensor element, and the yaw motor is decelerated by the reducer. The outer gear ring of the yaw bearing is driven to rotate through the small gear at the end of the reducer to achieve yaw to wind, so that the unit can obtain high power generation, and it can also minimize the load impact on the unit caused by oblique wind. The unit is equipped with an unwinding sensor, which can automatically unwind and brake.

[0037] Pitch system: The pitch mechanism uses electric pitch and independent pitch. When the wind speed reaches the starting wind speed, the pitch mechanism rotates the blades along the long axis to the optimal lift state, so that the wind rotor can achieve the maximum capture efficiency. Above the rated wind speed, in order to limit the power output, the pitch mechanism gradually rotates the blades in the feathering direction, reducing the aerodynamic efficiency of the wind rotor and maintaining constant power output. The pitch system nested inside the hub has two main functions: when the wind speed is below the rated wind speed, the blade pitch angle is zero to ensure maximum wind energy utilization; when the wind speed is above the rated wind speed, the rated power output is guaranteed by adjusting the blade pitch angle.

[0038] Both the yaw system and the pitch system are prior art.

[0039] Transmission system: The transmission system composed of the main shaft, gear box, coupling, etc. realizes the transmission of the mechanical energy generated by the impeller to the generator. The main shaft is a low-speed shaft. When the wind speed is low, its rotation speed is relatively low. The gear box realizes the speed increase through the interaction between large and small gears to achieve the purpose of making full use of the low wind speed.

[0040] Power generation system: converts mechanical energy into electrical energy and transmits it to the power grid.

[0041] The wind turbine model is connected to an outdoor small wind measuring device. When the wind source simulation device is switched to the actual wind speed operation mode, it will operate at the real-time wind speed measured by the wind measuring device. The wind source simulation experiment equipment can conduct simulation experiments in two modes: actual wind speed operation and simulated wind speed operation. When operating at the actual wind speed, the real-time wind speed measured by the outdoor small wind measuring device is used as the benchmark to drive the asynchronous traction motor to simulate the operation process of the actual wind turbine at the wind speed; when operating at the simulated wind speed, the given wind speed can be input through the operating console to drive the asynchronous traction motor to simulate the operation according to the given wind speed.

[0042] Through the inverter modulation grid connection process, the voltage and current parameters are measured and read, and the conditions on both sides of the stator and rotor and the generator are fed back to the inverter to modulate the DC bus voltage. When the parameters meet the grid connection conditions, a grid connection instruction is issued to connect to the grid in real time. When the generator is in a subsynchronous state, the stator outputs energy to the grid. When the generator is in a synchronous state, the stator and rotor supply power to the grid at the same time. In addition to the conventional simulation of wind turbine operation, the control system of this experimental system also has high and low voltage ride-through functions. According to the low voltage ride-through requirements of the power grid for wind farms, the software control strategy is improved and designed, and the voltage protection limit is modified. It is divided into the following three stages:

[0043] 1) From the time the voltage drops below 90% of the rated voltage, the voltage does not drop below 20% of the rated voltage within 640ms, and the voltage detection module does not report a fault;

[0044] 2) From 640ms to 3s after the start of low voltage ride-through, the voltage rises to 90% of the rated voltage, and the voltage detection module does not report a fault;

[0045] 3) After 3s, low voltage ride-through is completed and the voltage should be maintained above 90% of the rated voltage.

[0046] Low voltage ride-through: Grid low voltage detection mainly relies on the low voltage ride-through state start signal sent by the inverter as the control starting point. When the inverter detects a grid voltage drop, its control mode is converted to grid support mode. Through the change of the status bit of the inverter to the main control, the main control system confirms that it is in the low voltage ride-through state. After the grid voltage returns to the original value, the low voltage ride-through mode will be turned off, and the active power will increase to the set value (from zero to rated power) at a ramp rate of 100ms. The following functions can be realized:

[0047] 1) Increase the speed limit of the variable pitch system in power generation mode (originally 5° / s), and the maximum speed limit of the variable pitch system during low voltage ride-through is 10° / s.

[0048] 2) While ensuring the stability of the speed waveform, appropriately reduce the speed filter factor to improve the response speed of the pitch controller to speed changes.

[0049] 3) Ensure that there is no overshoot and the speed is stable by increasing the P and D parameters of the pitch controller, so that the pitch speed response is faster;

[0050] 4) During the active power recovery phase, in order to ensure the stability of the speed, the hysteresis control interval parameters in the speed controller are adjusted.

[0051] High voltage ride-through: During high voltage in the grid, the inductive reactive power is absorbed through converter control. The voltage on the DC side of the converter and the power devices is reduced by the voltage-dividing effect of the equivalent inductance on the grid side, avoiding the action of hardware protection. During high voltage in the grid, the grid-side converter of the doubly-fed wind turbine needs to work in a rectification state of absorbing active and inductive reactive power from the grid, or in an inversion state of transmitting active power to the grid and absorbing inductive reactive power from the grid, depending on the speed. The rotor-side converter needs to work in an inversion state of transmitting active power to the grid and absorbing inductive reactive power from the grid, that is, the rotor-side converter transmits active power to the grid and inductive reactive power required by the grid-connected guidelines through generator control. The coordination of the main control system and the converter is required for the wind turbine to achieve fault ride-through. The system control of the main control system and the converter during high voltage ride-through is basically the same as that of low voltage ride-through. After receiving the grid voltage increase fault signal from the converter, the main control system needs to shield some faults related to high voltage ride-through (such as protection signals such as high grid voltage and converter output power deviation from the command value), give up the power control right of the main control system, and set a reasonable grid high voltage ride-through protection curve. During the high voltage ride-through, the active and reactive power output of the wind turbine is determined by the converter control. After receiving the grid voltage recovery signal from the converter, the main control system restores the previously shielded fault or alarm signal, restores the control right over the wind turbine power, and realizes the normal operation and power generation of the wind turbine.

[0052] The primary frequency regulation has the ability to simulate the frequency regulation, peak regulation and standby of the power system; when the active power of the wind farm is more than 20% of its total rated output, all wind turbines in the field with active output exceeding 20% ​​of the rated power should be able to achieve continuous and smooth adjustment of active power and participate in the system active power control. In the control system, the software control strategy of the wind turbine master control is improved. It mainly focuses on modifying the overspeed protection value and the power control subroutine. In the power limiting operation scheme with variable speed control as the main and variable pitch control as the auxiliary, when the speed is low, the power limit can be achieved by increasing the speed; when the speed exceeds the operating range, the variable pitch is used for power limiting control, which can reduce the impact of frequent startup of the pitch angle controller on the whole machine.

[0053] The beneficial effects of the present invention are that the present invention can be programmed autonomously, simulated and controlled for different systems, and continuously power regulated for different forms of grid-connected models, and possible faults can be simulated through autonomous programming. By controlling the traction motor and the yaw system, the degree of use can be as close to natural wind as possible, and the experimental effect produced is closer to the actual wind turbine.

[0054] The wind source simulation experiment equipment has low voltage ride-through and high voltage ride-through capabilities, which can ensure that when the terminal voltage of the power generation system drops to a certain value during the operation of the wind source simulation experiment equipment, the wind source simulation experiment equipment can avoid the occurrence of grid disconnection and ensure the normal operation of the wind source simulation equipment.

Claims

1. A control method for wind source simulation experimental equipment for comprehensive energy in a park, characterized by: This control method uses the inverter to modulate the grid connection process. By measuring and reading the voltage and current parameters, the conditions on both sides of the stator and rotor and the generator are fed back to the inverter to modulate the DC bus voltage. When the parameters meet the grid connection conditions, a grid connection instruction is issued and the grid connection is achieved in real time. When the generator is in a subsynchronous state, the stator outputs energy to the grid. When the generator is in a synchronous state, the stator and rotor supply power to the grid at the same time. The voltage protection limit is modified according to the grid's requirements for wind farm ride-through. Low Voltage Ride-Through: It is divided into the following three stages: 1) The voltage does not fall below 20% of the rated voltage within 640ms after the voltage drops below 90% of the rated voltage, and the voltage detection module does not report a fault; 2) From 640ms to 3s after the start of low voltage ride-through, the voltage rises to 90% of the rated voltage, and the voltage detection module does not report a fault; 3) After 3s, low voltage ride-through is completed and the voltage should be maintained above 90% of the rated voltage; Low voltage ride-through (LVRT): Grid low voltage detection relies primarily on a LVRT start signal from the inverter as a control starting point. When the inverter detects a grid voltage drop, its control mode switches to grid support mode. The main control system confirms the LVRT state through changes in the status bit sent by the inverter to the main control system. After the grid voltage returns to its original value, the LVRT mode is disabled, and the active power increases to the set value, from zero to rated power, at a ramp rate of 100ms. High voltage ride-through: During periods of high grid voltage, the converter controls the absorption of inductive reactive power. During periods of high grid voltage, the grid-side converter of the doubly-fed wind turbine operates in a rectification state, absorbing active and inductive reactive power from the grid, or in an inversion state, transmitting active power to the grid and absorbing inductive reactive power from the grid, depending on the speed. The rotor-side converter must operate in an inversion state, transmitting active power to the grid and absorbing inductive reactive power from the grid. After receiving a grid voltage increase fault signal from the converter, the main control system must shield some faults related to high voltage ride-through, relinquish power control to the main control system, and set a reasonable grid high voltage ride-through protection curve. During high voltage ride-through, the active and reactive power output of the wind turbine is determined by the converter. After receiving a grid voltage recovery signal from the converter, the main control system restores the previously shielded fault or alarm signal, recovers control of the wind turbine power, and enables normal power generation by the wind turbine. The experimental equipment used in the above control method includes a nacelle arranged on a tower (6), a hub (9) is provided at the front end of the nacelle, blades (7) are provided on the hub (9), an asynchronous traction motor (18) is provided in the nacelle, one end of the asynchronous traction motor (18) is connected to a doubly fed wind generator (3) through a rigid coupling (2), the other end of the asynchronous traction motor (18) is connected to a gearbox (13), the other end of the gearbox (13) is connected to a low-speed shaft (11) through a support bearing, and the low-speed shaft (11) is connected to the hub (9); a torque sensor (1) is provided between the asynchronous traction motor (18) and the doubly fed wind generator (3); A yaw gear (5) is provided between the nacelle and the tower (6), and the yaw gear (5) is meshed with a gear of a yaw motor (17) provided in the nacelle; Doubly fed wind turbine generator (3): adopts a wound rotor induction generator, the generator stator is connected to the grid through a grid-connected switch, and the rotor is connected to the grid through a four-quadrant converter; The wind turbine model is externally connected to a control cabinet and an operating table; a small wind measuring device is built outdoors and connected to the wind turbine model via a communication line as a wind measuring system of the wind source simulation experimental equipment.

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