Patent Publication Number: US-2018045167-A1

Title: Wave-wind mutually supplementing power supply system for continuous power generation

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to power generation. More particularly, the invention relates a system in which sea wave power generation is combined with wind power generation to reach the goal of stable, continuous power generation. 
     2. Description of the Prior Art 
     Wind power generation has become quite common and humanity has used it for a long time. Technologies related to wind power generation has reached maturity; it is easy to install and has a low maintenance cost. Many countries have encouraged the use and installation of wind power generation facilities. However, wind power generation has its drawback, for example, unstable. When winds are too weak, a generator can not be driven and power generation would be interrupted; when winds are too strong, power generation would also be interrupted because the whole system of wind power generation is forced to shut down to avoid mechanical damages that could be inflicted by the strong winds. 
     Another form of natural energy is sea waves, which propagate on the surface of a sea. When winds blow on the surface of a sea, air pressure and friction brought by the winds would transfer some energy from the winds to the surface. 
     In comparison to wind power generation, wave power generation has a greater potential and would not be frequently interrupted because seas cover 70% of the earth&#39;s surface and sea waves take place on a constant, long-term basis. Therefore, technologies related to wave power generation have gained attention. 
     Technologies related to wave power generation are relatively new and it takes a lot of money to build facilities of wave power generation. In addition, facilities of wave power generation may be built near or at the site where the facilities of wind power generation are located. 
     According to the relevant studies, either wind energy or wave energy varies in a cyclical manner and they have a correlation coefficient of 0.8; in addition, in comparison to wind energy, wave energy is more predictable. When winds or waves are too weak, they can not be used to generate electricity; when they are too strong, mechanical damages may be done to the facilities and facilities may be forced to shut down. With regard to wind power generation or wave power generation, there is a transitional period between the time facilities start to move and the time when stable power generation is reached. At any location of a sea, the transitional period of wind power generation is not numerically identical to the transitional period of wave power generation. If they can be made to complement each other, the goal of long-term power generation may be reached and a higher payoff may be attained.  FIGS. 5 to 7  illustrate how wave height, wind velocity and wind direction vary in the same 1,500-hour period (please see  Prediction of wave height based on the monitoring of surface wind, Oceanography,  2012, page 169-188, by Tsukasa Hokimoto). 
     To come up with a system in which wave power generation may complement the existing wind power generation facilities, the inventor has put in a lot of effort in the subject and has successfully come up with the system of the present invention. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a wave-wind mutually supplementing power supply system for continuous power generation to combine wave power generation with wind power generation and to reduce down times so as to achieve the goal of long-term continuous power generation and to provide an optimal natural energy harnessing option. 
     Another object of the present invention is to provide such system, in which wave power generation may be combined with wind power generation. The system is easy to install and maintain and has a lower cost. Therefore, the system would be a good option in solving the urgent energy shortage problem. 
     The wave-wind mutually supplementing power supply system of the present invention has a wave kinetic energy module. The wave kinetic energy module is disposed on/in a sea and may generate electricity through the motion of sea water. The electricity so generated is combined with a wind power generation device to provide continuous power generation. The wave kinetic energy module comprises a wave energy harnessing unit, a transmission shaft, a generator unit, a torque adjusting unit and an automatic control unit. The wave energy harnessing unit may harness the kinetic energy generated through the motion of sea waves. The transmission shaft may transmit the kinetic energy harnessed by the wave energy harnessing unit to the generator unit and the generator unit may receive the kinetic energy transmitted from the transmission shaft and convert it to electricity. The torque adjusting unit is mounted on the transmission shaft so as to adjust the torque of the latter. The automatic control unit has a microprocessor and a sea water motion sensor unit so as to adjust the torque of the transmission shaft and control the activation of the generator unit according to the motion of the sea water. 
     In addition, the wave energy harnessing unit has a float unit. The float unit is connected with a central ball screw or a central toothed rod, which may move in sync with the float unit. The central ball screw is connected with a bevel gear, which engages with two one-directional bevel gear pieces, which rotate in opposite directions and are linked with the transmission shaft. In such manner, as the float unit moves up and down with the sea water, the central ball screw moves in sync with the float unit and then such vertical motion passed through the bevel gear to the two one-directional bevel gear pieces, which cause the transmission shaft to rotate in a single direction. Then, such rotation may drive the generator unit. 
     Furthermore, the generator unit comprises two coaxially disposed generators with different wattages. When sea waves move in smaller amplitudes, the automatic control unit would only activate the generator with the lower wattage so as to achieve higher power generation efficiency at lower torques. When sea waves move in larger amplitudes, the automatic control unit would switch to activate the generator with the higher wattage so as to achieve higher power generation efficiency at higher torques. As sea waves move in even larger amplitudes, the automatic control unit would activate both of the two generators to reach the peak level of power generation. 
     Preferably, both of the two generators of the generator unit are coreless disk type generators. 
     Preferably, one of the two generators is 200 KW generator and the other is 300 KW generator. 
     In actual operation, the 200 KW generator is activated as wave heights are lower than 1.5 meters; the 300 KW generator is activated as wave heights are between 1.5 and 3.0 meters; both of the two generators are activated as sea wave heights exceed 3.0 meters. 
     Preferably, the torque adjusting unit is a continuous torque varying device, which may adjust to vary rpm and torque. A torque meter is linked to the transmission shaft and may measure the torque values of the transmission shaft and pass the numerical values to the automatic control unit, which may in turn automatically adjust the rpm of the transmission shaft. 
     Moreover, the automatic control unit is provided with an electronic stabilizer, which is electrically linked with the torque adjusting unit and may stabilize the rpm of the torque adjusting unit when the motion of sea wave changes abruptly. 
     There are many types of the sea water motion sensor unit. Preferably, a sea water motion data collecting float unit is used to collect motion data of sea water. 
     Preferably, the sea water motion sensor unit is a linear displacement sensor, which may measure and record the vertical displacements of sea water. 
     Preferably, the sea water motion sensor unit may be an ultrasonic wave height meter or a laser wave height meter, which use ultrasonic or laser signals to measure the vertical displacements of sea water. 
     In comparison to the prior art, the system of the present invention may be used to provide long-term continuous power generation; in addition, the system is easy to install and maintain and has a lower cost. Therefore, the system would be a good option in solving the urgent energy shortage problem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating the system of the present invention. 
         FIG. 1 a    is a perspective view of the wave energy harnessing unit, which is provided with a ball screw. 
         FIG. 1 b    is a perspective view of the wave energy harnessing unit, which is provided with a toothed rod. 
         FIG. 2  is a view schematically illustrating how the wave kinetic energy module of the present invention is used with the facilities of wind power generation. 
         FIG. 3  is a diagram illustrating two generators with different wattages can harness a broader range of energy in the present invention. 
         FIG. 4  is a diagram illustrating a single generator may extract energy from a limited, narrower range of energy in the prior art. 
         FIGS. 5 to 7  illustrate how wave height, wind velocity and wind direction vary in the same 1,500-hour period. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The wave-wind mutually supplementing power supply system of the present invention, as illustrated in  FIGS. 1 and 2 , has a wave kinetic energy module  10 . The wave kinetic energy module  10  is disposed on/in a sea and may generate electricity through the motion of sea water  30 . The electricity so generated is combined with a wind power generation device  20  for continuous power generation. The wave kinetic energy module  10  may be installed at the same site where an existing wind power generation device  20  is disposed, hence sharing the same underwater cables and eliminating additional land acquisition cost and construction cost. Furthermore, electricity needed in after-installation periodic maintenance may be drawn from the existing wind power generation device  20 . 
     The wave kinetic energy module  10  comprises a wave energy harnessing unit  100 , a transmission shaft  110 , a generator unit  120 , a torque adjusting unit  130  and an automatic control unit  140 . 
     The wave energy harnessing unit  100  is placed near the surface of a sea  30  to harness the kinetic energy generated through the motion of sea waves. 
     The transmission shaft  110  may transmit the kinetic energy generated by the wave energy harnessing unit  100  to the generator unit  120  so as to generate electricity. 
     The generator unit  120  may receive the kinetic energy transmitted from the transmission shaft  110  and convert it to electricity. 
     The torque adjusting unit  130  is mounted on the transmission shaft  110  so as to adjust the torque of the latter. 
     The automatic control unit  140  has a microprocessor  141  and a sea water motion sensor unit  142  so as to adjust the torque of the transmission shaft  110  and control the activation of the generator unit  120  according to the motion of the sea water  30 . 
     In addition, the wave energy harnessing unit  100  has a float unit  101 . The float unit  101  is submerged into a sea and may move in sync with the sea water  30  so as to extract the kinetic energy from the sea waves. The float unit  101  is connected with a central ball screw  102 , which may move in sync with the float unit  101 . The central ball screw  102  is connected with a bevel gear  103 , which engages with two one-directional bevel gear pieces  104 , which rotate in opposite directions and are linked with the transmission shaft  110 . In such manner, as the float unit  101  moves up and down with the sea water  30 , the central ball screw  102  moves in sync with the float unit  101  and then such vertical motion passes through the bevel gear  103  to the two one-directional bevel gear pieces  104 , which cause the transmission shaft  110  to rotate in a single direction. Then, such rotation may drive the generator unit  120 . Because the sea water  30  moves on a constant basis, the generator unit  120  can be driven on a constant basis. In addition, such power supply system is used with a wind power generation device  20  so as to improve and stabilize electricity output. 
     Now, please see  FIG. 1 a   . The central ball screw  102  comprises a nut portion  1021  and a body portion  1022 . The nut portion  1021  is connected with the float unit  101  via several connective rods  1023 . The body portion  1022  is connected with the bevel gear  103 . In such manner, the nut portion  1021  is driven by the float unit  101  and thus moves in a linear manner; the body portion  1022  and thus the bevel gear  103  may move in a rotational manner. 
     The reasons for the choice of the ball screw  102  are its higher levels of stability and strength, which may maximize the power generation efficiency. Alternatively, a toothed rod, as illustrated in  FIG. 1 b   , may be used. In  FIG. 1 b   , the float unit  101  is connected with a toothed rod  105 , which may drive a cogwheel  103 . 
     In either case, the two one-directional bevel gear pieces  104  are allowed to rotate in opposite directions. Therefore, it does not matter whether the float unit  101  moves upward or downward, one of the two one-directional bevel gear pieces  104  would be driven so as to achieve a higher efficiency. 
     Please refer to  FIG. 3  now. The generator unit  120  comprises two coaxially disposed generators: a 200 KW generator and a 300 KW generator. When wave height is less than 1.5 meters and sea waves move in smaller amplitudes, the automatic control unit  140  would only activate the 200 KW generator so as to achieve higher power generation efficiency at lower torques. When wave height is between 1.5 meters and 3.0 meters and sea waves move in larger amplitudes, the automatic control unit  140  would switch to activate the 300 KW generator so as to achieve higher power generation efficiency at higher torques. As wave height exceeds 3.0 meters and sea waves move in even larger amplitudes, the automatic control unit  140  would activate both of the 200 KW and 300 KW generators or optionally, activate a single 500 KW generator. 
       FIGS. 3 and 4  illustrate the wave energy spectrum and wave spectral density of sea waves. In the prior art, as illustrated in  FIG. 4 , a single generator extracts energy from a limited range of energy. In contrast, in the present invention, as illustrated in  FIG. 3 , the generator unit comprises two generators: a 200 KW generator and a 300 KW generator, which may be selectively activated by the automatic control unit  140  according to different wave heights. Therefore, by a simple inspection of  FIGS. 3 and 4 , we can see that the generator unit of the present invention may extract more energy from sea waves. 
     Both of the two generators of the generator unit  120  may be coreless disk type generators to reduce wear and tear and lessen maintenance. Also, regular low-rpm generators may be used. 
     The torque adjusting unit  130  is a continuous torque varying device  131 , which may adjust to vary rpm and torque. A torque meter  143  is mounted on the transmission shaft  110  and may measure the torque values of the transmission shaft  110  and pass the numerical values to the automatic control unit  140 , which may in turn automatically adjust the rpm of the transmission shaft  110 . The torque adjusting unit  130  may also be an rpm enhancing device. 
     The automatic control unit  140  is provided with an electronic stabilizer  144 , which is electrically linked with the torque adjusting unit  130  and may stabilize the rpm of the torque adjusting unit  130  when the motion of sea waves changes abruptly. 
     There are many types of the sea water motion sensor unit  142  and one or several types of such sensors may be used. The sea water motion sensor unit  142  may be a sea water motion data collecting float unit  1421 , which may be used to collect motion data of sea water  30 . 
     Furthermore, the sea water motion sensor unit  142  may be a linear displacement sensor  1422 , which may measure and record the vertical displacements of sea water  30 . 
     Moreover, the sea water motion sensor unit  142  may be an ultrasonic wave height meter or a laser wave height meter  1423 , which uses ultrasonic or laser signals to measure the vertical displacements of sea water  30 . 
     Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.