An intelligent control system for residual water power generation

Abstract

The present invention relates to the technical field of power generation systems, and specifically to an intelligent control system for surplus water power generation, which can achieve stable output of a hydro-generator, save energy and improve efficiency. The control system comprises an upstream water storage reservoir, which is connected to a turbine through a pipeline, and the impeller outlet on the turbine is connected to a water collection tank. A frequency converter is installed on the turbine, and the frequency converter is connected in parallel to an energy storage capacitor and an energy feedback unit. The output side of the energy feedback unit is connected to a power grid. The pipeline comprises an upper pipeline, which is connected to the inlet of a tee pipe, one outlet of the tee pipe is connected to a control pipe, and the other outlet is connected to a bypass pipe. A first stop valve, a first flow sensor, and a first proportional control valve are provided on the upper pipeline, a second stop valve, a second flow sensor, and a second proportional control valve are provided on the control pipe, and a third stop valve is provided on the bypass pipe. The first flow sensor, the second flow sensor, and the frequency converter are connected to three input ends of a flow controller, and the three output ends of the flow controller are respectively connected to the first proportional control valve, the second proportional control valve, and the frequency converter, and are controlled by the flow controller.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation systems, and in particular to an intelligent control system for surplus water power generation. Background Art

[0002] Environmentally friendly and clean natural resources have always been the ideal energy source sought by the human world. Currently discovered and widely used natural energy sources include solar energy, hydroelectric potential, wind energy, geothermal energy, and tidal energy. Harnessing these known natural energies, extracting them cleanly and pollution-free through scientific methods and ensuring their recyclability, has been a new energy goal that my country has been committed to developing in recent years.

[0003] Water resources are a natural resource, particularly in my country, a region rich in mountains and plateaus. To preserve these resources, the construction of reservoirs and water storage facilities has long been a key national policy. Hydropower accounted for approximately 15% of Taiwan's electricity in 2022, and with an annual growth rate of approximately 1.5%, it is a key leader in renewable energy generation.

[0004] Surplus water power generation involves drilling holes in the reservoir dam of a hydropower station that has already been built according to the original design to utilize excess water resources for power generation. This process converts the potential energy of the water level into electricity, which can then be stored and applied to achieve energy conservation and emission reduction. A variety of surplus water power generation equipment has emerged, utilizing turbines and supporting technologies.

[0005] A turbine installed in a hydropower station rotates to generate electricity. Water from an upstream reservoir is introduced through a pipe into the turbine, rotating the impeller and driving the generator. The water, having completed its work, is then discharged downstream through a tail pipe. The turbine's output is related to the flow rate Q; the engine's power Po is related to the rotational speed ω.

[0006] The output power of traditional turbine power generation is not fixed and depends on the water storage status or working conditions of the reservoir at that time. Its principle diagram is as follows Figure 1 For example, when the water level is high, the water flow rate per unit time is high, the turbine rotates faster, and the generator power is also high. Conversely, when the water level is low, the generator power is low, and the energy efficiency is low. If the water level is too high, the speed is too fast, and the generator exceeds the operating load, some valves must be closed to reduce the flow rate, and the excess energy cannot be used. Summary of the Invention

[0007] In order to solve the problems of unstable output power, low efficiency and waste of surplus energy of existing hydro-generators, the present invention provides an intelligent control system for surplus water power generation, which can achieve stable output of hydro-generators, save energy and improve efficiency.

[0008] The technical solution is as follows: an intelligent control system for surplus water power generation, which includes an upstream water reservoir, which is connected to a turbine through a pipeline, and the impeller outlet on the turbine is connected to a water collection tank. It is characterized in that a frequency converter is installed on the turbine and the frequency converter is connected in parallel to an energy storage capacitor and an energy feedback unit, the output side of the energy feedback unit is connected to a power grid, the pipeline includes an upper pipeline, the upper pipeline is connected to the inlet of a tee pipe, one outlet of the tee pipe is connected to a control pipe, and the other outlet is connected to a bypass pipe, and a first stop valve, a first flow sensor are provided on the upper pipeline. The first proportional control valve is provided on the control pipeline, and the second stop valve, the second flow sensor, and the second proportional control valve are provided on the bypass pipeline. The first flow sensor, the second flow sensor, and the frequency converter are connected to the three input ends of the flow controller. The three output ends of the flow controller are connected to the first proportional control valve, the second proportional control valve, and the frequency converter respectively. Assuming that the flow in the upper pipeline is Q1, the flow in the control pipeline is Q2, and the flow in the bypass pipeline is Q3, Q1≥Q2+Q3, the control process of the flow controller is as follows:

[0009] S1: Read the flow data Q2 from the second flow sensor, and perform ratio processing on Q2 and the set value to obtain the ratio data Q. If Q>102%, enter S2; if Q<97.5%, enter S3. If 97.5%≤Q≤102%, the flow is in a balanced state, the flow controller is reset, the turbine runs at rated speed, the generator runs at rated power, and the energy feedback unit is at optimal efficiency.

[0010] S2: The flow rate is too large. The flow controller controls the second proportional control valve to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the minimum opening amplitude and Q is still greater than 102%, it is determined whether the inverter frequency is less than 90% of the rated frequency. If not, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If so, the inverter frequency is reduced. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still greater than 102%, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends.

[0011] S3: The flow rate is too small. The flow controller controls the second proportional control valve to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the maximum opening amplitude, Q is still less than 97.5%. It is judged whether the inverter frequency is greater than 110% of the rated frequency. If not, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If yes, the inverter frequency is increased. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still less than 97.5%, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends.

[0012] It is further characterized in that three pipelines are provided between the upstream water reservoir and the turbine.

[0013] After adopting the present invention, the flow rate feedback from the flow sensor can be processed by the flow controller to control the opening size of the first and second proportional control valves and the frequency of the inverter, so that the power generation can be maintained at the rated speed with maximum efficiency, which can make the hydro-generator output stable, save energy and improve efficiency; further, three pipelines are set between the upstream water reservoir and the turbine, that is, there are three groups of power generation systems, which decompose the power generation efficiency of the water flow, and then concentrate the electric energy, which is uniformly fed back to the power grid by the energy feedback unit. The power generation energy-saving efficiency can reach about 93%, which is significantly improved compared with the power generation efficiency of 67-87% of the traditional turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the prior art;

[0015] Figure 2 This is a schematic diagram of a first embodiment of the present invention;

[0016] Figure 3 This is the flow sensor control flow chart;

[0017] Figure 4 This is a schematic diagram of the second embodiment of the present invention;

[0018] Figure 5 This is the schematic diagram of the three-way power generation system;

[0019] Figure 6 This is the wiring diagram for a three-way power generation system. DETAILED DESCRIPTION

[0020] Example 1: See Figure 2 , Figure 3As shown, an intelligent control system for surplus water power generation includes an upstream water reservoir 1, which is connected to a turbine 2 through a pipeline. The impeller outlet of the turbine 2 is connected to a water collection tank 3. The turbine 2 is equipped with a frequency converter 5 connected to a generator 4, and the frequency converter 5 is connected in parallel to an energy storage capacitor 6 and an energy feedback unit 7. The output side of the energy feedback unit 7 is connected to a grid power supply 9 through a filter 8. The pipeline includes an upper pipeline 10, which is connected to the inlet of a tee pipe 11. One outlet of the tee pipe 11 is connected to a control pipe 12, and the other outlet is connected to a side pipe. The bypass pipeline 13 is provided with a first stop valve 14, a first flow sensor 15, and a first proportional control valve 16 on the upper pipeline 10, a second stop valve 17, a second flow sensor 18, and a second proportional control valve 19 on the control pipeline 12, and a third stop valve 20 is provided on the bypass pipeline 13. The first flow sensor 15, the second flow sensor 18, and the frequency converter 5 are connected to the three input ends of the flow controller 21, and the three output ends of the flow controller 21 are respectively connected to the first proportional control valve 16, the second proportional control valve 19, and the frequency converter 5.

[0021] In order to better and more intuitively understand the flow information, a first flow indicator 22 and a second flow indicator 23 are respectively provided next to the first flow sensor 15 and the second flow sensor 18 .

[0022] When selecting a tee, it is recommended to use a 120° Y-type. The main reason is that the water flow resistance of the T-type is greater than that of the Y-type, which generates invisible energy consumption during potential energy conversion, especially when the flow resistance is proportional to the flow velocity.

[0023] The control pipeline is the core component of this application for energy saving. The installation position of the second proportional control valve 19 and the second flow sensor 18 should be as close as possible in the middle of the pipeline. The choice of position is absolutely related to the flow control response, because the slope and length of the pipeline also affect the intercepted signal difference. In addition, the distance between the control pipeline and the control cabinet should be as close as possible to avoid actual signal distortion and interference during the debugging and installation process, which will affect the accuracy of the control process.

[0024] The signal of the flow controller 21 adopts the analog signal 4-20mA, and the algorithm controls the flow valve adjustment, which is realized by PI control. By collecting the flow in the upper pipeline as Q1 and the flow in the control pipeline as Q2 data, Q1 ≥ Q2 + Q3, Q3 is the flow in the bypass pipeline, and the target is the speed of the turbine, that is, the working point has the highest power generation efficiency, the motor runs at the rated speed, and the appropriate first proportional control valve 16 and second proportional control valve 19 control the flow.

[0025] The flow controller 21 is a core component of intelligent control. Through two flow sensors, it regularly feeds flow data from the pipeline into the flow controller 21. The implementation scheme uses a sampling period of at least 1000ms to monitor and control changes in pipeline flow. The control output signal directly controls the first and second proportional control valves 16 and 19, increasing or decreasing the valve openings based on the flow feedback. The flow rate directly affects the impeller speed of the turbine at the end of the pipeline. If the speed is too fast, the opening amplitude is reduced to reduce the flow rate. If the speed is too slow, the opening amplitude is increased to increase the flow rate. Maintaining the impeller speed at the rated motor frequency optimizes power generation efficiency. The controller algorithm primarily controls the flow rate in the pipeline, and indirectly, the impeller speed. Feedback control is based on the flow rate from the two channels, and the specific implementation scheme uses a PI closed-loop control loop. During the commissioning process, the parameters P and I are adjusted based on the system's time constant τ. This simple and uncomplicated control method achieves the desired effect of maintaining the rated speed of the downstream motor.

[0026] The inverter is the direct drive component for the turbine to generate electricity. The primary implementation involves fixing the frequency output to the rated speed of the permanent magnets within the turbine. The inverter preferably features permanent magnet motor drive functionality, preferably using the MTPA algorithm. For more demanding applications, closed-loop control can be implemented, with a motor-mounted speed encoder installed to provide actual speed feedback to the inverter. If the motor speed decreases, the inverter can adjust the speed appropriately, typically by increasing the frequency by approximately 10-20% to maintain the rated motor speed. This can be used to compensate for flow failures that do not meet the impeller's requirements.

[0027] See Figure 3 As shown, the control process of the flow controller is as follows:

[0028] S1: Read the flow data Q2 from the second flow sensor, and perform ratio processing on Q2 and the set value to obtain the ratio data Q. If Q>102%, enter S2; if Q<97.5%, enter S3. If 97.5%≤Q≤102%, the flow is in a balanced state, the flow controller is reset, the turbine runs at rated speed, the generator runs at rated power, and the energy feedback unit is at optimal efficiency.

[0029] S2: The flow rate is too large. The flow controller controls the second proportional control valve to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the minimum opening amplitude and Q is still greater than 102%, it is determined whether the inverter frequency is less than 90% of the rated frequency. If not, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If so, the inverter frequency is reduced. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still greater than 102%, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends.

[0030] S3: The flow rate is too small. The flow controller controls the second proportional control valve to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the maximum opening amplitude, Q is still less than 97.5%. It is judged whether the inverter frequency is greater than 110% of the rated frequency. If not, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If yes, the inverter frequency is increased. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still less than 97.5%, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends.

[0031] A hydro-turbine generator consists of an impeller and a generator. The generator structure consists of a stator and a rotor, with the rotor or motor preferably being a permanent magnet type. The preferred turbine type is the impulse type, as this maintains constant water pressure, minimizes kinetic energy conversion to electrical energy, and can achieve an efficiency exceeding 95%.

[0032] Energy storage capacitors, preferably film capacitors, are structurally superior to electrolytic capacitors in withstand voltage, eliminating the need for voltage division and parallel connection. Electrically, their ripple parameters are also superior to those of electrolytic capacitors, making them suitable for use in the energy storage device of the present invention. In the specific implementation of the energy storage device, the specific number of DC busbars (+) and (-) and the electrical specifications of the contacts need to be coordinated with the number and power of the distributed capacitors.

[0033] The energy regeneration unit is connected directly in parallel with the energy storage capacitor on the DC side. When implemented on the AC output grid, grid harmonics and their suppression must be considered. LLC and LCL filters, or an AFE harmonic suppression module, may be necessary to prevent harmonics generated during power input from affecting other electrical equipment. The power rating of the energy regeneration unit must take into account the total power of the distributed system at full load, and is generally designed to operate at 110-120% load on all power generation equipment.

[0034] Example 2: See Figure 4 As shown, two additional pipelines are added on the basis of the first embodiment, that is, it becomes a three-way power generation system 24. The rest of the structure is the same and will not be described in detail.

[0035] The planned total power generation can be decomposed into three power generation systems. Each power generation system can maximize its energy efficiency through intelligent control, and then the generated electricity is concentrated into a storage capacitor. Finally, through an energy feedback unit, the unified surplus water generated electricity is fed back to the power grid, achieving the effect of energy conservation and emission reduction. Figure 5 、 Figure 6 As shown, the DC side (+) and (-) ends of the inverters in the three power generation systems are connected to the energy storage capacitors (+) and (-), and are connected in parallel with the DC ends (+) and (-) of the energy feedback unit, and the AC end of the feedback unit is connected to the grid RST.

[0036] When the turbine rotates, the generator works, passes through the inverter, and the inverter outputs a rotating magnetic field, which cuts in the opposite direction of the permanent magnet. The generator operates in the four-quadrant power generation state. The generated electric energy directly enters the storage capacitor. The electric energy property is direct current. The direct current then passes through the energy feedback unit, the IGBT and control circuit inside the energy feedback unit, and converts the direct current into 380V / 50Hz constant voltage and frequency alternating current and enters the power grid.

[0037] The following is a specific case to illustrate the difference between this application solution and the traditional solution.

[0038] A reservoir in a mountainous area has a planned total power generation capacity of 2000kW / H. The reservoir is 40 meters high and has a maximum and minimum flow rate of approximately 3500-5000m 3 / H. The operating flow is 6500m 3 / H.

[0039] The power generation system adopts distributed or traditional planning.

[0040] The traditional planning is as follows

[0041] SJ-W-560 turbine, flow rate 1.321m 3 / s, asynchronous motor power 560kw.

[0042] Through measurement, the turbine efficiency is 85%, the power generation efficiency is an average of 79%, and the system loss is 3%.

[0043] Power Generation 1out = fluid density × G × flow rate × potential energy height × turbine efficiency × generator efficiency × loss rate

[0044] =1000×9 .8×1.371×40×85%×79% (1-3%)=350kW / H

[0045] The distributed surplus water intelligent power generation system of the present invention is adopted, and the power generation system is distributed into three sets.

[0046] SJ-W-25 turbine, flow rate 0.521m 3 / s, water output 248kw, generator SFW250, rated power 250kw, 1000 RPM (r / s). The turbine generator uses a permanent magnet motor.

[0047] Through measurement, the turbine efficiency is 85%, the intelligent power generation efficiency is an average of 91%, and the total loss of the three systems is 9%.

[0048] Power generation 3*P 2out = fluid density × G × flow rate × potential energy height × turbine efficiency × generator efficiency × loss rate

[0049] =3*1000×9 .8×0.521×40×85%×91%×(1-9%)=460kW / H

[0050] Energy saving and emission reduction compared with the original traditional method (460-350) / 350×100%=30%

[0051] The distributed system power generation of the present invention has a total power generation capacity that is approximately 30% higher than the original typical energy saving. The main difference is reflected in the power generation efficiency, which can be adjusted according to the flow rate to determine the power generation efficiency of the generator.

[0052] Annual energy savings (460-350kW / H) × 8000 hours = 880,000 kWh. (Based on 8000 hours of annual operation)

[0053] Annual energy savings: (460-350kW / H) x 0.35 = 30 tons of standard coal (based on the 2022 standard of 350g / KWH).

[0054] The technical background, working principle, main features, preferred matters and specific implementation methods of the present invention are described above. Technical practitioners involved in energy conservation or related industries should understand that the present invention is not limited to the above-mentioned implementation cases or implementation methods. The above-mentioned implementation examples and descriptions are only for illustrative purposes of the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have other changes and improvements, which are all within the scope of the invention claimed for protection. The scope of protection claimed for the present invention is defined by the appended claims and their equivalents.

Claims

1. An intelligent control system for surplus water power generation, comprising an upstream water reservoir connected to a turbine via a pipeline, wherein the impeller outlet on the turbine is connected to a water collection tank, characterized in that: The turbine is equipped with a frequency converter, which is connected in parallel to an energy storage capacitor and an energy feedback unit. The output side of the energy feedback unit is connected to a power grid. The pipeline includes an upper pipeline, which is connected to the inlet of a tee pipe. One outlet of the tee pipe is connected to a control pipe and the other outlet is connected to a bypass pipe. A first stop valve, a first flow sensor, and a first proportional control valve are provided on the upper pipeline. A second stop valve, a second flow sensor, and a second proportional control valve are provided on the control pipe. A third stop valve is provided on the bypass pipe. The first flow sensor, the second flow sensor, and the frequency converter are connected to three input ends of a flow controller. The three output ends of the flow controller are respectively connected to the first proportional control valve, the second proportional control valve, and the frequency converter. Assume that the flow in the upper pipeline is Q1, the flow in the control pipeline is Q2, and the flow in the bypass pipeline is Q3. Q1≥Q2+Q3. The control process of the flow controller is as follows: S1: Read the flow data Q2 from the second flow sensor, and perform ratio processing on Q2 and the set value to obtain the ratio data Q. If Q>102%, enter S2; if Q<97.5%, enter S3. If 97.5%≤Q≤102%, the flow is in a balanced state, the flow controller is reset, the turbine runs at rated speed, the generator runs at rated power, and the energy feedback unit is at optimal efficiency. S2: The flow rate is too large. The flow controller controls the second proportional control valve to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the minimum opening amplitude and Q is still greater than 102%, it is determined whether the inverter frequency is less than 90% of the rated frequency. If not, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If so, the inverter frequency is reduced. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still greater than 102%, the first proportional control valve is controlled to reduce the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. S3: The flow rate is too small. The flow controller controls the second proportional control valve to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. When the second proportional control valve reaches the maximum opening amplitude, Q is still less than 97.5%. It is judged whether the inverter frequency is greater than 110% of the rated frequency. If not, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends. If yes, the inverter frequency is increased. If 97.5%≤Q≤102%, the flow regulation ends. If Q is still less than 97.5%, the first proportional control valve is controlled to increase the opening amplitude until 97.5%≤Q≤102%, and the flow regulation ends.

2. The intelligent control system for surplus water power generation according to claim 1, characterized in that: Three pipelines are provided between the upstream water reservoir and the turbine.

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