A tidal energy power generation operation control method

Abstract

The present invention discloses a tidal energy power generation operation control method, the steps are sequentially entering a standby state, entering a start state, entering a power generation operation state, entering a stop state, entering a direction change state, and then repeating the previous process; through the above control steps, the flow rate data is completely unnecessary during the start and stop and power generation process of the unit, thus avoiding the disadvantages of the current underwater current meter being unreliable and easy to damage, resulting in frequent failures of the flow rate data and the unit having to be shut down. At the same time, the unit protection problem in this process is comprehensively considered, the power and speed parameters are monitored, and the protection shutdown program is entered at any time to prevent the unit from being damaged due to unexpected situations.

Description

Technical Field

[0001] The present invention belongs to the technical field of ocean energy power generation, relates to the control of tidal energy generator sets, and specifically to an operation control method of tidal energy generator sets that does not rely on flow velocity data. Background Art

[0002] Tidal energy is a type of ocean energy. It uses the water flow energy formed by the rise and fall of the tide to generate electricity. It is a green and clean energy. The flow rate and direction of the tide changes over time during the tidal period. Tide is a very regular natural phenomenon. The daily tide table for a fixed area can be accurately calculated several years ago. The closer the time interval, the more accurate the tidal law. Using this characteristic of the tide, the unit control method does not rely on flow rate data throughout the unit process.

[0003] Although the tidal laws are relatively accurate, they are currently only applicable to places with measurement points. The berths of tidal energy generators are often far away from the measurement points. Therefore, there are still certain differences in the time laws of the tides, and they cannot be directly applied. It is necessary to introduce multiple data for comprehensive judgment.

[0004] Current tidal energy generators are similar to wind power generation. They both start and stop the units by monitoring the flow velocity and direction of the incoming flow near the installation point of the units. They start when the flow velocity is low, wait for the flow velocity to gradually increase, and then perform corresponding control based on the flow velocity data. They shut down the units after the flow velocity decreases.

[0005] Since my country's tidal energy-rich sea areas are located near the coast, the underwater sediment content is high, which is conducive to the growth of marine organisms. As a result, underwater current meters frequently malfunction due to problems such as seal failure, probe obstruction by marine organisms, corrosion, and impact on the current meter body or lines. Once the flow rate data is abnormal, the unit can only be forced to shut down, greatly increasing the unit's failure time and maintenance costs. Summary of the invention

[0006] In order to solve the above problems in the prior art, the present invention proposes a tidal energy power generation operation control method that does not rely on flow rate data control.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve the technical problem is: a tidal energy power generation operation control method, the steps are as follows:

[0008] (1) First, the initial power generation start time of the generator set is calculated based on the high and low tide time closest to the detection point of the berth where the unit is installed on the tidal table, combined with the start time of the previous power generation, and the two are calculated separately or comprehensively, and then the generator set enters the start-up preparation state in advance for a certain period of time; if the flow direction angle enters the deviation range of the specified main tide direction at the same time, the unit is controlled to start and enter the standby state, at which time the unit brake is released and the unit can rotate freely;

[0009] (2) As the tidal energy gradually increases, when the speed of the unit reaches the pre-set grid-connected speed, the unit is controlled to enter the startup state. At this time, the main control commands the inverter to start the generator-side and grid-side grid-connected program to allow the unit to generate electricity and connect to the grid. Then the unit is controlled to enter the power generation operation state. During operation, the unit adopts the torque control method or the constant speed control method to track the unit's higher efficiency point for power generation through the pre-set power speed curve;

[0010] (3) As the tidal energy gradually decreases, when it is detected that the power generation of the unit is continuously less than the lower value for a certain period of time, the unit is controlled to enter the shutdown state, and the unit applies reverse torque through the inverter to reduce the speed, the unit stops generating electricity, and the brake is applied;

[0011] (4) According to the flow direction data, when the tidal current changes direction, the unit is controlled to enter the direction-changing state, and the unit moves to the power generation position that adapts to the other tidal direction by yaw or pitch change;

[0012] (5) Repeat step (1).

[0013] Furthermore, in the step (1), when the unit is started for the first time, the unit can obtain the start time through automatic calculation or directly manually input the start time. When the unit is operating normally, the start time is obtained through automatic calculation without manual intervention, thereby realizing automatic operation.

[0014] Furthermore, in addition to using tidal forecast table data, the start-up time can be estimated by recording the previous start-up times after subsequent operation, and combined with the tidal flow direction data to obtain a more accurate and safe start-up time.

[0015] Furthermore, in the step (2), a torque control method is adopted when the unit is running below the rated power; and a constant speed control method is adopted when the unit is running at the rated power.

[0016] Furthermore, in step (3), the speed of the medium frequency converter is reduced to nearly 0, and then the mechanical brake is applied, so that the impact on the unit can be minimized.

[0017] Furthermore, when the flow direction data in step (4) changes to the slack tide direction, the water velocity is minimum, the yaw or pitch resistance is minimum, and the vibration impact of the unit is also minimum.

[0018] The beneficial effect of the present invention is that, through the above control method, the flow rate data is completely unnecessary during the start-up and shutdown and power generation process of the unit of the present invention, thus avoiding the disadvantages of the current underwater current meter being unreliable and easy to be damaged, resulting in flow rate data failure and then unit shutdown. At the same time, the unit protection problem is considered in this process to prevent the unit from being damaged due to unexpected situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the control algorithm of the present invention. DETAILED DESCRIPTION

[0020] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make adjustments to them as needed to adapt to specific application scenarios.

[0021] Reference Figure 1 As shown, the present invention discloses a tidal energy power generation operation control method, the steps are as follows.

[0022] (1) First, the initial power generation start time of the generator set is calculated based on the high and low tide time closest to the berth detection point on the tidal table and the start time of the previous power generation. Then, the generator set is put into the start preparation state a certain time in advance (such as 15-30 minutes, which can be adjusted according to actual conditions); next, combined with the tidal flow angle measurement data, if the flow angle simultaneously enters the deviation range of the specified main tidal direction, the unit is controlled to start and enter the standby state. At this time, the unit brake is released and the unit can rotate freely.

[0023] When the unit is started for the first time, the unit can obtain the start time through automatic calculation or direct manual input of the start time. When the unit is operating normally, the start time is obtained through automatic calculation without manual intervention, realizing automatic operation. In addition to using the tidal forecast table data, the start time can be calculated by recording the previous start times after subsequent operation, and combined with the tidal flow direction data to obtain a more accurate and safe start time.

[0024] (2) As the tidal energy gradually increases, when the speed of the unit reaches the pre-set grid-connected speed, the unit is controlled to enter the startup state. At this time, the main control command inverter starts the machine-side and grid-side grid-connected program to allow the unit to generate electricity and connect to the grid. Then the unit is controlled to enter the power generation operation state. During operation, the unit adopts the torque control method or the constant speed control method, and tracks the unit's higher efficiency point for power generation through the pre-set power speed curve.

[0025] When the unit is running below the rated power, it is recommended to use the torque control method. When the unit is at the rated power, it is recommended to use the constant speed control method, which can obtain the maximum operating efficiency. Of course, it can also be adjusted according to the actual situation.

[0026] (3) As the tidal energy gradually decreases, when it is detected that the power generation of the unit is continuously less than a lower value (such as 5kW, which can be adjusted according to actual conditions) and lasts for a certain period of time (such as 10s, which can be adjusted according to actual conditions), the unit is controlled to enter the shutdown state, and the unit applies reverse torque through the inverter to reduce the speed. The unit stops generating electricity and brakes.

[0027] Since the actual energy at this time is already very low, the inverter can reduce the speed to close to 0 and then perform mechanical braking, which can minimize the impact on the unit.

[0028] (4) According to the flow direction data, when the tide direction changes, the unit is controlled to enter the change direction state, and the unit moves to the power generation position that adapts to the other tide direction by yaw or pitch change. It is recommended that when the flow direction data changes to the flat tide direction, the water flow velocity is the smallest, the yaw or pitch change resistance is the smallest, and the vibration impact of the unit is also the smallest.

[0029] (5) Repeat step (1).

[0030] During the entire control process, there is no need to rely on flow rate data for control; during the entire control process, there are maximum speed and maximum power parameter monitoring. When the speed or power exceeds the set limit, the inverter is first used to apply reverse torque to stop the machine, and then the mechanical brake is applied. If the inverter fails, the machine is directly stopped by the mechanical brake to avoid dangerous situations.

[0031] Flow rate data can also be added to the entire control step as an auxiliary judgment. When the data is abnormal, it serves as a warning signal rather than a shutdown signal, which can remind the monitoring staff on duty to pay special attention and then proceed to the next step based on the actual situation, which can further improve the reliability of the unit operation.

[0032] The above embodiments are only illustrative of the principles and effects of the present invention, as well as some embodiments of its application. For those skilled in the art, several modifications and improvements may be made without departing from the creative concept of the present invention, and all of these belong to the protection scope of the present invention.

Claims

1. A tidal current energy power generation operation control method, characterized in that: The steps are as follows (1) Based on the high and low tide times of the detection point closest to the unit installation berth on the tidal table and the start time of the previous power generation, the initial power generation start time of the generator unit is calculated, and then the generator unit enters the start preparation state in advance; If the flow direction angles simultaneously enter the deviation range of the specified main tide direction, the unit will be controlled to enter the standby state, the unit brake will be released, and the unit will rotate freely; (2) When the speed of the unit reaches the set grid-connected speed, the unit is controlled to enter the startup state, the inverter starts the grid-connected program, the unit generates electricity and is connected to the grid, and the unit enters the power generation operation state. During operation, the unit adopts the torque control method or the constant speed control method, and tracks the high efficiency point of the unit to generate electricity through the set power speed curve; (3) When the power generation of the unit is continuously less than the lower value for a certain period of time, the unit is controlled to enter the shutdown state, the unit applies reverse torque through the inverter to reduce the speed, the unit stops generating electricity, and the brake is applied; (4) When the tidal current changes direction, the unit enters the direction-changing state, and the unit moves to the power generation position that adapts to the other tidal direction by yaw or pitch change; (5) Repeat step (1).

2. A tidal current energy generation operation control method according to claim 1, characterized in that: In the step (1), when the unit is started for the first time, the start time is obtained by automatic calculation or manually input start time; when the unit is running normally, the start time is obtained by automatic calculation.

3. A tidal current energy generation operation control method according to claim 2, characterized in that: The subsequent operation uses the recorded start-up times of the previous times to estimate the next start-up time, and then combines the tidal flow direction data to determine the precise start timing.

4. A tidal current energy generation operation control method according to claim 1, 2 or 3, characterized in that: In the step (2), the torque control method is adopted when the unit is running below the rated power; the constant speed control method is adopted when the unit is running at the rated power.

5. A tidal current energy generation operation control method according to claim 4, characterized in that: In step (3), the inverter speed is reduced to nearly 0, and then the mechanical brake is applied, which can minimize the impact on the unit.

6. A tidal current energy generation operation control method according to claim 5, characterized in that: In the step (4), when the flow direction data changes to the slack tide direction, the yaw or pitch resistance is minimized.

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