JPH0220831B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling air flow in three states by means of a hinged valve and its control circuit for increasing the air output of a wave power generator air chamber.

Based on the practical experience of using air turbine type wave power generators for navigational beacon buoys, research has been carried out with the aim of achieving high output using large floating wave power generators (Kaimei, etc.), as well as studies on shore-fixed types. ing.

The present inventors have been making efforts to commercialize air turbine type wave power generators through actual sea experiments with large floating wave power generators (Kaimei) and research on their improvement. There are the following issues that need to be resolved.

(A) Even in the waves of the Sea of Japan where the actual ocean experiment was conducted, the wave period varies from 4 seconds to 12 seconds. Among these waves, waves with a duration of 4 to 6 seconds have a low wave height, but they occur in large numbers throughout the year. Good power generation with such small waves is especially necessary to increase the average level of power generation output. Long-period waves with a period of 8 to 10 seconds and a wavelength of about 100 m to 160 m have high energy, and with such long-period waves, the utilization efficiency of an air turbine with a constant nozzle aperture ratio decreases.

(B) When increasing the size, it is necessary to stop power generation and ensure the safety of the equipment and system. This is one of the functions required by the provisions of the Electricity Business Law.

The present invention aims at the above two technical improvements and is characterized by the combination of the following points.

(1) In a wave power generator that converts the energy of sea waves into aerodynamic force and rotates an air turbine to generate electricity, an air outlet or other suitable By installing a hinge-type valve in the passage and combining the valve's closing characteristics and ability to maintain the open position with a servo mechanism, it is possible to handle waves with relatively long wavelengths by controlling the speed of each wave obtained from signals such as wave height or water pressure. The valve is opened and closed for each wave to control the phase of the air flow and the phase of the air pressure to match, greatly improving the air output for waves with long wavelengths. On the other hand, for waves with short wavelengths, the valve is controlled to be kept in the open position at all times, and the airflow is normally reciprocated to ensure optimal operation in short periods. Next, in the event of a severe storm or other special circumstances, the valve is controlled to remain closed at all times to ensure the safety of the generator and load.

An air turbine type wave power generator having a hinge type valve having the above-mentioned functions and a control device characterized by its three-state air flow control method.

(2) A butterfly valve is used as a valve device that opens and closes to change the state of air flow, and the ability to keep the valve closed even when a large air pressure difference is applied from any direction due to the difference in pressure receiving area, and the ability to keep the valve closed once Combined with the ability of the valve to remain open until the pressure difference due to the air flow disappears after it has been opened, the butterfly valve enables three-state control of air flow with small servo forces and minimal power consumption. Equipped with an airflow opening/closing device.

(3) By using a valveless Wales turbine as the air turbine, energy loss due to air vortexes, etc. that occur during idle rotation, when the butterfly valve is closed and the turbine rotates without airflow, is minimized. By implementing the present invention, three different types of control can be achieved: power generation with improved efficiency from long-period waves, stopping power generation in times of storm or emergency, and maintaining normal operation in short-period waves. It is what makes it possible.

Regarding the phase control of the air flow mentioned in item 1 above, for example, Professor Buda of Norway states that by controlling the phase of the vertical movement of a buoy moored at one point using a latching mechanism, it is possible to increase the output by 3 to 4 times. Although there have been reports, research by the present inventors has revealed that there are many waves for which phase control is not always an effective means of improving output.

According to observations at Japan Sea Yura, waves with a period of 6 seconds or less account for 60% of the total waves in a year, and performing phase control on such waves may result in a significant decrease in output and efficiency. be. Furthermore, when phase control is performed, the air output increases, but on the other hand, the maximum air pressure in the air chamber is approximately four times that of the case without phase control, and even compared to the case where the valve is closed and the air outlet is eliminated. Therefore, from the point of view of the safety of the air chamber, it is better not to perform airflow phase control in the case of large waves, and the three-state airflow control of the present invention is based on this fact. This is what I did.

An example of the implementation of the present invention will be explained below with reference to the drawings. Fig. 1 is an overall layout diagram, in which the air chamber 1 is a room whose lower surface is open to the waves, and may be incorporated into a floating structure or placed in a rocky area on the coast. It is fixedly installed.

A water pressure gauge 2 is attached near the bottom of the air chamber 1 to detect the top and bottom of waves as water pressure, and the signal from this water pressure gauge 2 becomes the basic signal for control. An air turbine type generator 4 is placed in a power generation box 3 mounted above the air chamber 1.

In this embodiment, two Welsh turbines 5 and 6 are used.
The patent No.
1060243 is shown as an example, the air flow from the air chamber 1 passes through ducts 8 and 9, rotates the air turbines 5 and 6, and leads to the air outlet 10.

This air outlet 10 has a valve seat 11 and a gasket 12.
A hinge-type valve 13 adapted to this is held by a valve shaft 14, and a turbo motor 15 is provided to rotate the valve shaft 14 that passes through the air outlet 10 so as to be as airtight as possible, as shown by a solid line. The valve is controlled from the closed position shown by the dotted line to the open position shown by the dotted line.
Valve stop hardware 16 limits the open position of hinged valve 13.

Next, the automatic closed position holding ability, which is one of the operating functions of the hinged valve 13, will be explained using FIG. 2. A small weight 17 for return is attached to one side of the hinge type valve 13, and in a normal state, the hinge type valve 13 is in a folded state in close contact with the gasket 12.

With the hinged valve 13 in close contact with the gasket 12 in this way, the air pressure 18 above the valve 13 is
P ₁ , the lower air pressure 19 is P ₂ , the area of one side of the valve is S ₁ , the area obtained by subtracting the packing contact area from this is S ₂ , the area from the axis of the point of application of the synthetic air force applied to S ₁ is If the distance is L ₁ and the distance from the axis of the point of action of the synthetic aerodynamic force on S ₂ is L ₂ , then the moment to close the valve due to P ₁ is P ₁ S ₁ L ₁ −P ₁ S ₂ L ₂ = P ₁ (S ₁ L ₁ − S ₂ L ₂ ) The moment to close the valve due to P ₂ is P ₂ S ₁ L ₁ − P ₂ S ₂ L ₂ = P ₂ (S ₁ L ₁ − S ₂ L ₂ ) Therefore, the moment for closing the valve due to P ₁ and P ₂ is (P ₁ + P ₂ ) (S ₁ L ₁ − _{S 2} L ₂ ), and S ₁ L ₁ − S ₂ L ₂ >0. Therefore, regardless of changes in P ₁ and P ₂ , the hinged valve 13 always has a counterclockwise moment around the valve stem 14 that closes the valve and maintains its closure.

In order to open this valve, it is necessary to apply a clockwise moment larger than the moment for holding the valve closed by an external force of the servo motor 15.

The ability of the hinged valve 13 to maintain its closure is very effective in ensuring the closing action of the air flow. That is, if the servo motor 15
When the valve does not operate, no matter how large the air pressures P ₁ and P ₂ become due to waves, the valve will not open until it is damaged, and from a design point of view, it is a good thing as long as the valve is strong enough. This is one of the functions required for valve control, and is important as a basic valve characteristic that makes it possible to stop the rotation of the turbine and generator in response to an emergency command.

Next, the hinged valve 1 was opened by the servo motor 15.
3 reaches a position where its movement is restricted by the valve stopper fitting 16 as shown in Fig. 3, but at this position the air flows 20 and 21 generated by the air pressure difference P ₁ -P ₂ =△P disappear. In order to maintain the open position until the opening, various design measures are required.

The one shown in Figure 3 has air resistance plates 22 and 23 attached to both ends of the hinged valve 13 in opposite directions as shown in the figure, so that the air flow is always maintained both when the air flow is 20 and when the air flow is 21. As long as it is present, the aerodynamic force will keep the valve in the open position.

Fig. 4 shows another device, hinge type valve 1.
The hinge type valve 13 shown in FIG. 5 is a flat plate type, which allows the valve 3 to maintain its open position due to its curved shape.
Cover plates 24 and 25 so that the air flow hits one side of the valve.
This is an example in which the airflow is provided in the airflow passage.

Next, regarding wave height, it is known that water pressure changes as the wave height changes.

FIG. 6 is a record of changes in water pressure detected by the water pressure gauge 2 for control purposes, and is data proportional to changes in wave height. Waves in actual sea areas are irregular waves, and when comparing wave height and period, it can be said from experience in wave height measurement that the period is less irregular, and the period between waves has relatively little variation.

From FIG. 6, the wave height H26 and the period T27 are determined. An example of a control circuit that generates a control signal from this wave height data will be explained with reference to the control circuit block diagram in FIG.

When the data on the wave height meter 28 exceeds a certain standard wave height, a command is issued to the hinge type valve servo stop circuit 30 to stop the trigger command circuit 34. On the other hand, the times of the crests and troughs of the waves are obtained by the basic trigger command circuit 31 which accurately indicates the times of the crests and troughs of the waves. In addition, the average period calculation circuit 32 operates based on the data of the period meter 29, and calculates the average period Tmean.
From this, the hinged valve 13 is in the fully open position when the wave reaches a peak or trough and the phase of the air pressure reaches its peak value, and the internal wave front in the air chamber 1 has a rising or falling speed. so that the peak value is reached and both the peak values of air pressure and air velocity are in the same phase.
The trigger time is calculated by taking into account the response delay time Td of the hinged valve 13 including the servo motor so that the hinged valve 13 fully opens before T _{0 /} 4 of the natural vibration period T 0 of the air chamber 1. The circuit calculates Tmean/2-T ₀ /4-Td=Ta, that is, the trigger delay time Ta, and first delays the trigger command from the basic trigger command circuit 31 by Ta.The trigger command circuit 34 then opens and closes the hinged valve 13. An open signal is sent to the servo motor 15. However, it will not operate if there is a signal from the hinge type valve servo stop circuit due to a command in the event of a heavy traffic or emergency.

To explain the relationship between the respective times obtained in FIG. 7 in FIG. 6, the trough 35 of the wave is determined by the basic trigger command circuit 31, and the time 37 corresponding to T ₀ /4 before the crest 36 of the next wave is determined. Trigger delay time Ta39 is calculated by subtracting 38 corresponding to Td from half of the average period Tmean/2, and the hinged valve 13 opening signal is issued at the trigger point 40. On the other hand, when the value of Tmean from the average cycle calculating circuit 32 is short, an opening signal for the hinged valve 13 is output. Of course, it is possible to accurately predict the point of the next peak and find the trigger point 40 from this, but accurate calculation of the altitude is required to accurately predict the peak of the next wave of irregular waves, so this is not recommended in this book. In the example, a simple method was explained. In another embodiment, instead of measuring the time of the peak and trough of the wave, the time of the zero crossing of the wave may be measured. In this case, the opening signal to the hinged valve 13 opening/closing servo motor 15 obtained from theoretical values and water tank experimental values is approximately 20 to 30 degrees behind the zero cross of the external wavefront, assuming one cycle of 360 degrees, if the servo delay is ignored. That's fine. Then,
from the average period calculation circuit 32 calculated separately.
Based on Tmean, Tmean×25°/360°=0.07Tmean=Tb is calculated, and in addition to the time when the external wave front crosses zero, an open signal is sent to open the hinged valve 13. This design is simpler and more practical than any other control circuit.

FIG. 8 shows an example of a servo mechanism, in which an arm 41 is attached to the shaft 14 of the hinge type valve 13, and a connecting portion 42 is attached to this arm 41, which is connected to a piston shaft 43.
The air piston cylinder 44 is the air piston cylinder 4
It's in 5. The high pressure air from the high pressure air chamber 46 pulls the magnet 47 in response to a signal from the trigger command circuit 34, opens the air valve 48, puts the high pressure air into the air piston cylinder 45, moves the air piston cylinder 44, and moves the piston shaft 43 and the connecting part. 4
2. Rotate the hinged valve 13 around the shaft 14 through the arm 41 to open the hinged valve 13. however,
It does not operate when there is no signal from the trigger command circuit 34, that is, when there is a heavy rush or when a stop signal is issued from the hinge type valve servo stop circuit 30.

On the other hand, when the air piston cylinder 44 moves and passes through the air escape port 49 to the outside, the air tries to escape to the outside. In waves other than waves with short periods at the beginning of wave development or waves with high wave heights that are considered dangerous for the safety of the equipment, there is no special signal from the average period calculation circuit 32, so the magnet 50 does not operate and the air is discharged. , the air piston cylinder 44 returns when the air pressure difference ΔP disappears. In this case, the return weight 17 attached to the hinge type valve 13 returns to the closed state.

Next, when the average period Tmean becomes extremely short (for example, 5 seconds or less), the average period calculation circuit 32
The magnet 50 is pulled by the signal from the hinged valve 1, which closes the air valve 51, air is not exhausted, and the air piston cylinder 44 remains open.
3 is always open.

FIG. 9 shows the primary conversion efficiency of a fixed air chamber having the function of operating as described above, that is, the conversion efficiency from waves to air energy when wave energy equal to the width of the air is input.

In the figure, the solid line 52 indicates the wave energy conversion efficiency when the hinged valve 13 is open, and the dotted line 53 indicates the wave energy conversion efficiency when the hinged valve 13 is operated and controlled. be.

From the above, for short-period waves, the solid line 52 appears, while the hinged valve 13 is kept open, and for long-period waves, the dotted line 5
The hinge type valve 13 is controlled so that the angle becomes 3. Furthermore, if the wave height exceeds the standard for severe storms, the hinged valve 13 is held closed to stop the rotation of the air turbine and generator, and to prevent damage caused by waves.

This ensures optimal operation of the air turbine generator at all times and enables safe and economical practical use.

Note that when air flow three-state control is implemented, air passes through the air turbine at a very high speed in a lash state in a short period of time. Therefore, an air turbine adapted to this high-speed air flow naturally tends to rotate at high speed. However, under other conditions where the valve is closed and the airflow is stopped, the rotor blades of the air turbine rotating at high speed become idle, generating vortices in the air and causing a large power loss, which greatly reduces the high speed rotation of the turbine. be done. For this reason, it is necessary for the moving blades of the air turbine to have a minimum cross section in the direction of rotation, and to have a small resistance force in the direction of rotation in the air.

The optimal turbine for the above conditions is the Wales turbine shown in Figure 10, which has a symmetrical blade cross section with no pitch angle. The air resistance force during rotation is extremely small. Therefore, using a Wales turbine as an air turbine is very effective and necessary for improving performance.

[Brief explanation of drawings]

FIG. 1 is an overall layout diagram showing one example of the implementation of the present invention, and FIGS. 2 to 5 are the first to fourth embodiments of the present invention.
FIG. 6 is a water pressure change record diagram, FIG. 7 is a control circuit diagram, FIG. 8 is a sectional view of an example of a servo mechanism, and FIG. The energy conversion efficiency curve diagram, FIG. 10, shows cross-sectional views of blades of various turbines. The symbols in the drawings indicate the following members, respectively. 1: Air chamber, 2: Water pressure gauge, 3: Power generation box, 4: Generator,
5: Wales turbine, 6: Wales turbine, 7: Generator shaft, 8: Duct, 9: Duct, 1
0: Air outlet, 11: Valve seat, 12: Packing, 1
3: Hinge type valve, 14: Valve stem, 15: Servo motor, 16: Valve stopper hardware, 17: Small weight for return, 24: Lid plate, 25: Lid plate, 28: Wave height meter, 29: Period meter, 30 : Hinge type valve servo stop circuit, 31: Base trigger command circuit, 32: Average period calculation circuit, 33: Trigger time calculation circuit, 3
4: Trigger command circuit, 41: Arm, 42: Connecting section, 43: Piston shaft, 44: Air piston cylinder, 45: Air piston cylinder, 46: High pressure air chamber, 47: Magnet, 48: Air valve, 4
9: Air escape port, 50: Magnet, 51: Air valve, 54: Impulse type turbine rotor blade, 55: Propeller type rotor blade, 56: Wales turbine rotor blade.

Claims (1)

[Claims] 1. In order to obtain optimized air output from changing wave energy in the wave power generator air chamber,
A hinge type valve is provided at the air outlet or other suitable passage, and a servo mechanism for opening and closing the hinge type valve and a control circuit for operating the servo mechanism based on commands from a water pressure gauge are provided, and a control circuit for operating the servo mechanism based on commands from a water pressure gauge is provided. For waves with short wavelengths, the valve is controlled to open and close for each wave to match the phase of the air flow and the phase of the air pressure, and for waves with short wavelengths, the valve is controlled to be kept in the open position at all times. A three-state air flow control device for an air chamber of a wave power generator, characterized in that it performs three-state control so that the valve is always closed in times of emergency or other necessity. 2 A butterfly valve is used as the hinge type valve, and its pressure receiving area allows the valve to remain closed even when a large air pressure difference is applied in any direction. A three-state air flow control device for a wave power generator air chamber according to claim 1, characterized in that the device maintains its position. 3. A wave height meter and a period meter connected to the water pressure gauge are provided as the control circuit, and the sea waves to be measured are irregular waves, but the period tends to be relatively constant,
If the period meter is sequentially connected to the trigger command circuit via an average cycle calculation circuit and a trigger time calculation circuit, and the wave height meter is connected to the trigger command circuit via a hinged valve servo stop circuit, and the calculated average cycle is short. A signal is generated to keep the hinged valve open, and a trigger signal to open the hinged valve is generated when the average period is long. The occurrence causes the hinged valve to open at a time delayed by Ta calculated by Tmean/2-To/4-Td=Ta from the natural vibration period To and the delay time Td of the hinged valve, and It is characterized by having a simplified control circuit that makes it possible to stop the trigger command circuit through the hinged valve servo stop circuit to maintain the hinged valve in a closed state when the wave height exceeds the reference wave height. A three-state air flow control device for a wave power generator air chamber according to claim 1. 4. An air piston cylinder is provided as a servo mechanism controlled by the control circuit to open and close a hinged valve via an arm and a piston shaft, and the air piston cylinder is moved from a high pressure air chamber against a magnet by a command from a trigger command circuit. Claims 1 or 3, characterized in that an air valve for supplying air is connected to the supply side, and an air valve that opens against the magnet according to a command from the average period calculation circuit is connected to the exhaust side. A three-state airflow control device for a wave power generator air chamber as described in . 5. Claim 1, characterized in that a valveless Welsh turbine is used as the air turbine.
A three-state airflow control device for a wave power generator air chamber as described in paragraphs. 6. The control circuit is characterized in that the trigger signal for opening the hinged valve when the average period is long is generated at a time delayed by approximately 0.07×Tmean=Tb from the zero-crossing time of the wavefront for the sake of simplicity. A three-state air flow control device for a wave power generator air chamber according to claim 1.