WO2010032012A1

WO2010032012A1 - System and method for hydraulic power transfer

Info

Publication number: WO2010032012A1
Application number: PCT/GB2009/002228
Authority: WO
Inventors: Philip Wesby; Roy Targonski
Original assignee: Philip Wesby; Roy Targonski
Priority date: 2008-09-19
Filing date: 2009-09-17
Publication date: 2010-03-25
Also published as: GB0817202D0

Abstract

A system and method for hydraulic power transfer is described which provides a step-up power transfer system in which high torque and tow rpm generate an output of high rpm. The system according to the invention can provide an improved method for power transfer in wind and wave turbines. The method makes possible the creation of a new class of wind and wave turbines having no mechanical gearbox which are lighter, cheaper, and more robust and which are easier and more efficient to service. One or a plurality of hydraulic pumps with a high hydraulic power ratio configured as a pump is/are coupled to the turbine shaft and connected hydraulically to one or more hydraulic pumps each configured as a motor having a low ratio or ratio of unity to drive the shaft of an electric generator and thereby generate power. A control system optimizes the operational parameters of the system, regulating the hydraulic fluid flow through the system via a servo control or control valve to constrict the hydraulic channel and or varies the power taken from, or delivered to, the generator to regulate the electrical power output to a predetermined frequency over a range of wind speeds/wave height displacements. A dosed or open loop system using one or more hydraulic fluid reservoirs is used to maintain the fluid volume in the system. In one arrangement, a plurality of turbines may be integrated together hydraulically with non-reverse valves to drive a single generator.

Description

SYSTEM AND METHOD FOR HYDRAULIC POWER TRANSFER

DESCRIPTION

BACKGROUND OF THE INVENTION

The invention relates to a system and method for hydraulic power transfer which is suitable for turbine power generation systems. More particularly, it relates to a system and method for hydraulic power transfer in wind and wave turbines and provides a power transfer system which does not require a mechanical gearbox. In particular, the invention teaches a method which makes use of fixed or differential ratio hydraulic pumps and a hydraulic transmission to couple the turbine rotor to an electric generator. The hydraulic pumps work together converting low rpm and high torque to give a high rpm output. The invention makes possible the creation of a new class of wind and wave turbines which are lighter, cheaper, and more robust and which are easier to install and service and more efficient to operate.

The current invention is particularly addressed towards the creation of a scalable wind turbine hydraulic power transmission system which can provide a highly efficient power transfer system for many power generation classes of wind turbine. The invention makes possible the creation of high efficiency wind turbines having a useful power output of 5kW to 2OkW suitable for schools and medical centres in off-grid locations. The system equally provides an optimum power solution for higher power wind turbines such as 10OkW to 15OkW suitable to power remote mobile phone base stations. The same hydraulic power transmission system invention can also be applied to high power multi-Megawatt wind turbines and thereby replace the extremely heavy conventional gearbox in these systems.

Generally, conventional wind turbines comprise gearboxes adjacent to the wind turbine rotor shaft to reduce the need for a long shaft. This requirement means that the wind turbine assembly including the gearbox must be supported by a very robust tower to support the high weight of the gearbox. Multi-Megawatt turbines typically have a gearbox weighing in excess of 20 tonnes. This arrangement places the gearbox transmission 20- 30m up in the air additionally making the turbine difficult to service. The difficulty of this servicing requirement is further compounded for marine off-shore wind turbines. A power transmission system which avoided the need to place heavy components at the top of the wind turbine support tower would make the system much easier to service.

Consequently, the invention brings significant advantages in installation and servicing wherever multi-Megawatt wind turbines are deployed such as in remote hilltop locations and offshore. The system and method according to the invention makes possible the relocation of most of the wind turbine transmission system elements to the base of the wind turbine structures thereby providing easy access to equipment, reducing the need for cranes on site and marine cranes out at sea when installing the systems, and significantly reducing the strength requirements of the mechanical support structure.

Today, it is standard practice to use mechanical gearboxes to transfer power from the turning turbine blades to drive an electric generator. Gearboxes are not as efficient as hydraulic transmission systems for power transfer and they have a high number of moving parts. Gearboxes must be regularly serviced to check that they contain sufficient oil to fully lubricate the gearbox elements to avoid problems of cavitation. A hydraulic power transmission is by nature self-lubricating.

Turbines are often located in places difficult to access for both installation of the turbine as well as for servicing. In addition, it would be beneficial if several turbines could be coupled together to drive the same electrical generator. The use of hydraulic transmission with non-reverse valves as described in the invention makes this possible.

In the area of health and safety, the invention makes possible the creation of a turbine transmission system which is easier and safer to install and service.

It is towards the creation of a new and more energy-efficient class of wind and wave turbines that the current invention is directed. In addition to the application to wave turbines, the system is equally directly relevant for ocean current and river current turbines, as well as tidal surge and tidal displacement turbines.

No systems are presently known to the applicants, which address this market need in a highly effective and economic way.

Further to the limitations of existing technologies used for power transfer in wind and wave turbines, and so far as is known, no optimised system and method for hydraulic power transfer is presently available which is directed towards the specific needs of this problem area as outlined.

OBJECTS OF THE INVENTION

Accordingly, it is an object of the present invention to provide an improved system and method for hydraulic power transfer in which one or more hydraulic pumps, each working as a pump, convert high torque and low revolutions per minute to drive at least one other hydraulic pump, working as a motor, to drive a high revolution per minute output thereby creating a step-up power transfer system from high torque, low rpm to give high rpm. It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer which can make possible the creation of a new dass of rugged and reliable, low cost, energy-efficient wind power generation and wave power generation turbines which are lighter and more robust and which are easier to install and service and more efficient to operate.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer which replaces the need for a mechanical gearbox in a wind or wave turbine by using hydraulic pumps such as gearpumps and or piston pumps and or vane pumps to transfer the wind or wave energy to an electric generator.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer which makes use of a first hydraulic pump - used as a pump - coupled to the turbine rotor which is hydraulically coupled to a second hydraulic pump - used as a motor - which drives the shaft of an electric generator.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer in which the shaft of a wind or wave turbine is coupled to a high ratio hydraulic pump used as a pump which is hydraulically coupled to a low ratio or unity-ratio hydraulic pump used as a motor which drives an electric generator.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which makes use of a new configuration of hydraulic pumps which work together to provide a step-up power solution by converting low revolutions per minute (rpm) at high torque to give a high rpm output. This is unlike all known conventional hydraulic transmission configurations in which high rpm is down-converted to give low rpm at high torque.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which makes use of a new configuration of hydraulic pumps which work together to provide a step-up power solution by converting low revolutions per minute (rpm) at high torque to give high rpm which may use hydraulic pumps of different types being either gearpumps, and or piston pumps and or vane pumps wherein the said hydraulic pumps may be fixed displacement pumps and or variable displacement pumps depending upon the application and the requirement for greater control of pressure and flow. It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which comprises a feedback control system to vary the power taken from the turbine rotor to maintain its operational efficiency to generate power over a range of wind speeds or over a range of wave height displacements.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which comprises an electronic power regulation control system which serves to optimize the operational parameters of the system by regulating the hydraulic fluid flow through the system via a servo control to constrict the hydraulic channel and or to vary the power taken from the generator and or the power delivered to the generator to regulate the electrical power output to a predetermined frequency and supply voltage over a range of wind speeds or wave height displacements.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which is scalable and makes possible the creation of a new class of high efficiency wind turbines having a useful power output of 5kW to 2OkW suitable for powering schools, medical centres, farms, remote monitoring centres and industrial units in off-grid locations.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which is scalable and makes possible the creation of a new class of high efficiency wind turbines having a useful power output of 10OkW to 15OkW suitable to power remote mobile phone base stations, radio repeater stations, microwave telecommunication links, air navigational aids, remote bases, vital installations, pumping stations and the like.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which makes possible the deployment of the electric power generator to a location at some distance from the turbine shaft.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which makes possible the deployment of the electric power generator to a location at some distance from the turbine shaft wherein several turbine systems may be hydrauiically coupled to the same electric power generator using non-reverse valves and thereby increase the wind power or wave power which is delivered to the said generator, In this case the electronic control system may control all elements of the combined turbine system to optimise the power generator over a range of wind speeds or wave displacement heights. It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer which makes possible the development of a new class of water based turbines which derive their power from tidal surges, or ocean currents, or river currents or tidal displacement.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which makes use of a control system which may be partially or completely electronic or partially or completely mechanical or partially or completely electromechanical in its make up. The control system may comprise a speed governor coupled to the rotor shaft which can work to regulate the hydraulic pressure depending upon the rotor speed.

It is a further object of one embodiment of the present invention to provide a system and method for hydraulic power transfer for wind and wave turbines which comprises one or more transducers such as a torque transducer, and or a flow transducer, and or a pressure transducer, wherein the output of the one or more said transducers is used to gather data about the torque generated by the shaft, and or the pressure of the hydraulic fluid, and or flow of the hydraulic fluid through the system such that operation of the system can be monitored and stored in an associated memory means both for the purpose of data togging and for system optimization purposes for a range of wind speeds or wave height displacements. The system comprises a fixed or wireless data connection both for relaying operational data which is logged as well as for remote diagnostic and system optimization purposes. A system controller linked to the said transducers and memory means intelligently manages the total hydraulic transmission system and power generation with reference to a self-learning algorithm which dynamically builds a relation between operational parameters and the optimal power output for a range of wind speeds or wave height displacements.

Other objects and advantages of this invention will become apparent from the description to follow when read in conjunction with the accompanying drawings.

BRIEF SUMMARY OF THE INVENTION

Certain of the foregoing and related objects are readily-attained according to the present invention by the provision of a novel system and method for hydraulic power transfer, which serves to address the diverse requirements for creating a new class of robust, high energy-efficient low-cost turbine having application to wind power generation and wave power generation.

The invention teaches a system and method for hydraulic power transmission which makes the first disclosure of a step-up hydraulic power transfer which converts low rpm and high torque to high rpm.

The invention makes possible the creation of a new class of useful power range wind and wave turbines which avoids the need for a mechanical gearbox and thereby avoids the challenges associated with such gearboxes which are heavy and need to be located close to the turbine shaft. The invention makes possible the relocation of a substantial part of the transmission system to a more convenient location thereby greatly facilitating installation, operation, servicing and repair. The system is self- lubricating and the turbine support structure can be ruggedly designed to address the requirements of the turbine shaft assembly. In the case of the wind turbine, the invention makes possible the creation of a multi- Megawatt wind turbine assembly which is up to 20 tonnes lighter thereby reducing the structural requirements of the support tower.

The use of the novel and inventive hydraulic transmission solution according to the invention even makes possible the relocation of the electric power generation means at some distance from the turbine assembly which is not possible with conventional gearbox driven wind turbines. This capability to locate different elements of the turbine transmission which is connected hydraulically makes possible the efficient combining of power generated by more than one turbine.

A dynamically balancing electronic control system, managed by an integrated system controller, fully controls all aspects of the system thereby optimising the electric generator power output over a range of wind speeds or wave height displacements. The capability to integrate several turbines together using non-reverse valves with the same electric generator and electronic power control system makes possible the creation of a highly efficient means of power generation.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings, which disclose several key embodiments of the invention. It is to be understood, however, that the drawings are designed for the purpose of illustration only and that the particular descriptions of the invention in the context of the wind turbine application are given by way of example only to help highlight the advantages of the current invention and do not limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic of a hydraulic power transfer system according to one embodiment of the invention.

FIG. 2 illustrates a schematic of the hydraulic power transfer control system according to one embodiment of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

Reference will now be made in detail to some specific embodiments of the invention including the best modes contemplated by the inventor for carrying out the invention. Examples of these specific embodiments are illustrated in the accompanying drawings. While the invention is described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to the described embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as defined by the appended claims.

The following description makes full reference to the detailed features which may form parts of different embodiments as outlined in the objects of the invention. In the following example reference is made to a system comprising gearpumps while it is to be understood that the invention covers other embodiments which use other types of hydraulic pumps such as piston pumps and vane pumps and the like. Other embodiments may use fixed or variable displacement hydraulic pumps.

Referring now in detail to the drawings and in particular FIG. 1 thereof, therein illustrated is a schematic showing a hydraulic power transfer system according to the invention.

In FIG. 1, is shown a turbine rotor (101) which may comprise a wind turbine vertical axis rotor, or a wind turbine horizontal axis rotor, or a rotary coupling to a wave displacement turbine, or an ocean current or river current turbine, or a tidal surge turbine. The turbine rotor (101) drives a turbine shaft (102) which itself is linked to a gearpump assembly (103) and the turbine shaft drives a gearpump (104) working as a pump where the gearpump transfers a volume of fluid for every revolution. In different embodiments the gearpump may comprise a fixed ratio gearpump or a dynamically variable ratio gearpump.

The length of the rotor shaft (102) is selected in accordance with other design parameters to enable the gearpump assembly (103) to be located near to or far from the turbine rotor (101). In a first preferred embodiment the gearpump (104) is a fixed ratio gearpump. The fixed ratio is selected in accordance with other system parameters and the desired power output of the generator. For example, if the blades turn at a speed between 100 rpm and 150 rpm, and the gearpump has a fixed ratio of 10: 1 and pumps lOcc of fluid per revolution, then between lOOOcc and 1500cc are pumped per minute.

Within the gearpump assembly (103) is shown a hydraulic reservoir (105) which surrounds the gearpump. This is shown in cross section in FIG. 1 where the reservoir (105) is toroidal in shape and connects to the gearpump (104) via a fluid feed (106) through which fluid is drawn into the gearpump and pumped from the gearpump into the hydraulic pipe (107) which provides the pressure to drive the gearpump (114) working as a motor which drives an electric generator (116).

A pressure relief vatve (108) is connected to the hydraulic pipe (107) as a safety feature to prevent the hydraulic pressure in the system from exceeding a preset value. A hydraulic return connection (111) enables fluid exceeding a preset pressure to be returned via the hydraulic return pipe (117) to the fluid reservoir (105).

The system also comprises a flow control/shutoff valve (109) which serves to lock the system by preventing fluid from being pumped towards the generator. Dynamic control of the pressure relief valve (108) in combination with the shutoff valve (109) makes possible a smooth slowing and braking of the system to a standstill without exerting high resistance loads which could cause damaging to the blades.

In the application for a wind turbine, very high winds might cause significant damage to the rotor blades causing them to spin out of control. Intelligent control of the upper pressure limit of the pressure relief valve (108) makes possible the stepwise change of the upper pressure limit from a lower to a higher value. At the same time, the fluid flow in the system is reduced by closing the flow control valve (109) which thus enables the rotary speed of the wind turbine blades to be slowed. In different embodiments this control may be fully electronic or partially mechanical such as being linked to a governor which serves to control different elements of the system mechanically.

The output power of the system is provided by the generator (116) which is coupled via a coupling (115) to a gearpump working as a motor (114) driven by the hydraulic pressure from the fluid which is pumped from the gearpump (104) via the pressure relief valve (108) and flow control/shutoff valve (109). The varying rotary speed of the turbine rotor shaft (102) over a range of values means that a range of voltage frequencies are output by the power generator (116). It is important that the system comprises the means to further control the hydraulic pressure of the system and thereby control the voltage frequency provided by the power generator (116). This is achieved by dynamic control of a hydraulic control valve (112) which is connected via connector (110) wherein the control valve (112) passes fluid via the hydraulic connection (113) to the return pipe (117). Intelligent dynamic control of the hydraulic control valve (112) in cooperation with other hydraulic system elements serves to control the output voltage frequency of the generator (116).

Essentially, by controlling the amount of hydraulic fluid returned to the fluid reservoir, the system is able to dump fluid as hydraulic ballast.

In tiie application of the transmission system for a wind turbine, the rotor blades will generate more torque when each blade directly faces the wind. This produces a variation in the hydraulic pressure delivered to the power generator. To smooth out this variation, a hydraulic accumulator (120) is connected to the hydraulic pipe (107) located between the gearpump (104) and the pressure relief valve (108).

A non-return valve (121) is fitted directly in front of the accumulator to prevent any fluid flowing back to the hydraulic pump (104).

To optimize the transmission system operation and to get the most efficient power transfer from the turbine, a system controller (shown in FIG.2) gathers data from the transmission system elements. In the preferred embodiment, a number of transducers are integrated with the system to provide data to a data logging means associated with the system controller. A turbine shaft torque transducer and shaft speed/rpm transducer (122) is integrated with the turbine shaft. A flow transducer (118) and a pressure transducer (119) are integrated into trie hydraulic pipe (107) before the non-return valve (121) of the hydraulic accumulator (120).

Now with reference to FIG. 2 is shown a schematic of the hydraulic transmission control system. The control system serves to optimise the power output of the generator (116) for a range of wind speeds or wave height displacements depending upon the turbine application.

A system controller (201) gathers data from a plurality of transducers (210) which may include a turbine shaft torque and or speed and or rpm transducer, a flow transducer, and a pressure transducer. Other transducers may be added depending upon the application.

A memory means (203) stores data about the system configuration. A data processing module (202) comprises a self-learning algorithm and serves to optimise the electric generator output over a range of wind speeds or wave height displacements. System parameters are stored in the optimum system performance parameters module (212). The updating of the parameters stored in this module (212) continues with time as the self-learning algorithm in the data processing module (202) generates more performance data over a greater period of time and for an increasing range of environmental conditions.

The system controller (201) controls the operation of the pressure relief valve (207), the flow control/shutoff valve (208) and the hydraulic control valve (209). Through feedback control, the self-learning algorithm determines the optimum settings of the pressure relief valve (207), the flow control/shutoff valve (208) and the hydraulic control valve (209) for a range of monitored turbine rotor speeds, rotor rpm, and rotor torque, fluid flow and hydraulic pressure levels.

In summary, the system controller (201) provides several key functions. It controls the hydraulic valves to restrict the hydraulic fluid flow and or close the hydraulic fluid flow completely and thereby stop the turbine from moving completely. It controls the turning speed of the wind turbine rotor. It optimises the rpm of the wind turbine rotor in different wind conditions and controls the power taken from the rotor when the rotor reaches the optimum rpm.

The data logger (204) gathers data about the system performance and power output for a range of wind speeds or wave height displacements. The real time environmental data such as temperature, air pressure and the like is gathered by the system controller (201) via environmental sensors (211). In this way the data processing module (202) is able to map the system performance and the control settings of all the integrated hydraulic control elements for a range of environmental conditions against the output of the electric generator. In this way the optimum settings are determined to give the most efficient power generation over the operational range of the turbine. As described earlier, these are stored in the optimum performance parameters module (212) and continuously updated.

A remote communications module (205) is connected to the system controller (201) and this can provide remote access to the turbine and the data logged and the system performance parameters.

The output of the electric generator is monitored continuously by a power control regulator (206). Depending upon the system configuration, the power control regulator also serves to control how the power generated by the turbine is used. Electric power may be output directly to power local facilities, or to feed into the power grid. Alternatively, power may be used to recharge a local battery back-up supply. Intelligent control of the electric generator may also be used to slow the turbine. In the instance that the generator is a permanent magnet generator (PMG), by controlling the excitation of the PMG, the magnetic flux density of the generator can be increased thereby making the generator shaft more difficult to turn. The level of excitation may be varied with reference to all other system parameters and the desired power output for any prevailing environmental conditions. The system controller (201) thus may control the power delivered to the generator as well as controlling the power output from the generator.

With further reference to electric power generation to power local facilities, the turbine is suited to generate 3-phase power in on-grid or off-grid locations. Electricity supply standards stipulate AC voltage frequency for many household and technical devices should be within 47Hz and 63Hz AC. This frequency output of the turbine can be maintained by the system controller according to the current invention.

In the wind turbine application, the back-up battery supply associated with the turbine has the capacity to provide power during periods of low wind speed conditions. A large enough battery back-up system can provide 24 hours of continuous power at the highest average power rating of the wind turbine. As mentioned earlier, the system controller must also regulate the recharging of the battery back-up system. This may be done by identifying periods of low power use such as during the night. Alternatively, emergency recharging of the battery back-up system may be prioritised dependent upon the charge status of the battery back-up system.

To help illustrate how the system works according to the invention, the following detailed example is given.

If the generator (116) is a 2-pole permanent magnet generator, and the turbine rotor shaft is turning at 150 rpm, the gearpump (104) will deliver l500cc per minute. If the system comprised no fosses, the output of the second gearpump would be driven at 1500rpm to generate an output voltage frequency of 50Hz AC.

If the generator (116) were a 4-pole permanent magnet generator, for no losses, a rotor shaft turning at 75rpm would generate 50Hz AC.

Generally we can consider a hydraulic system to be 80% efficient. Thus, in order to generate 1500 rpm using a 2-pole permanent magnet generator, the first gearpump should have a ratio of around 18:1 and transfer 18 cc per revolution.

Each time the turbine rotor makes a revolution, 18cc of fluid are pumped towards the second gearpump. The compressibility of the fluid can be considered as negligible at operating hydraulic pressure. A typical operating pressure of the hydraulic connection between gearpump (104) and gearpump (114) is 200bar.

A key element of this innovative system according to this first embodiment is the use of a first gearpump working as a pump coupled a second gearpump working as a motor. Moreover it is the very novel use of the pair of hydraulic pumps to work as a step-up power conversion, wherein low rpm of the rotor (101) and high torque, provide a high rpm output of the generator. Fluid pumped through the first gearpump causes the second gearpump to act as a motor which drives the shaft of the generator. It is the reversible characteristic of the gearpump, enabling it to act as a hydraulic pump when a shaft is turned to drive it, or to act as a motor to drive a shaft when increased hydraulic pressure is exerted on it, which is utilised in this system.

As mentioned, fluid within the transmission system between the gearpumps is at high pressure such as 200bar. Fluid passing out through the second gearpump, which drives the generator, returns to the reservoir (105) at atmospheric pressure. In this arrangement, the hydraulic fluid system forms an open loop hydraulic circuit. In an alternative arrangement two separate reservoirs may be used, one near to the generator and one near to the first gearpump and connected via a pump. In this arrangement, the hydraulic fluid system forms a dosed loop system.

An essential design feature is the need to provide sufficient capacity in the hydraulic fluid reservoirs to avoid cavitation in the gearpump whereby air pockets appear in the fluid flow. This can cause mechanical failure of the gearpump over time. Typically, the reservoir should hold an operational capacity of around three times the fluid passing through the system. With the wind turbine rotor turning at lOOrpm, a gearpump with a ratio of 18:1 will pump 1800CC of fluid per minute. The hydraulic reservoir should thus maintain a volume of 5400cc.

This hydraulic fluid system forms an ideal power transfer system for a wind turbine. In such an application, the variable nature of the wind means that tiie hydraulic power transfer must be regulated to maintain tile generator as close to 50Hz as possible. As described earlier, the data processing module (202) with its self-learning algorithm makes possible the mapping of operational parameters according to diversely different and changing environmental conditions which are stored in the optimum system performance parameters module (212) for the purpose of optimising the system performance and power output as required.

Control of power generation in higher wind speeds and changing wind conditions is thus made possible with reference to the optimum system performance parameters module (212). Differential control of all hydraulic elements is dynamically applied with reference to the real-time environmental conditions as determined via the environmental sensors (211).

The essential objective is to enable the wind turbine to generate optimum power over a range of wind speeds. Consequently, a key objective is to enable the wind turbine rotor to reach power generation speeds quickly and easily. This can be achieved by electronic control of the permanent magnet generator. De-excitation of the PMG will reduce the pressure of the system by reducing the ftux density of the PMG and the rotor will turn freely. It is through intelligent control of the power output and power delivered to the generator which makes it possible for the wind turbine to maintain optimum power generation mode over a range of wind speeds.

The system and method of the current invention has clear advantages over conventional mechanical gearbox transmission systems:

1. A hydraulic power transfer system offers a versatile high torque transfer system with a high step-up power conversion comprising only 2 moving components while the gearbox needs a large number of components.

2. The power density of the hydraulic system is much higher when compared to the equivalent physical volume of a mechanical gearbox. Consequently, a hydraulic system is much better suited for all wind turbine designs.

3. The weight of any mechanical gearbox system is very high when compared to a hydraulic system and the gearbox must be located directly adjacent to the wind turbine rotor. This is why huge and excessively strong structures are needed to support the massive gearboxes and rotors of megawatt wind turbines. The hydraulic system provides a very low weight system.

4. A hydraulic power transfer system can replace the mechanical gearbox solution of conventional wind turbines and thereby reduce the cost of the support tower as well as making possible the relocation of all hydraulic pump elements to the base of the tower. In this way, servicing of the wind turbine transmission is greatly simplified.

5. This hydraulic power transfer system provides the lowest cost power transfer system for a wind turbine.

6. The system is self-lubricating compared to a mechanical gearbox solution.

7. The hydraulic solution is much quieter than a mechanical gearbox solution.

While only several embodiments of the present invention have been described in detail particularly with reference to the wind turbine application, it will be obvious to those persons of ordinary skill in the art that many changes and modifications may be made thereunto without departing from the spirit of the Invention. As outlined earlier, the control means may be partially or fully replaced by mechanical and or electromechanical control systems coupled to a governor linked to the turbine shaft. The transmission system elements may be made of many different types of materials such as stainless steel, and or plastics and the hydraulic pumps may be made of ceramic materials. Bio-degradabie oils may be used in pollution sensitive «»^nwlronments. In some applications, water may be used as the hydraulic fluid where antifreeze or alcohol is added to improve the operating temperature range of the system in cold conditions.

The present disclosure is for illustration purposes only and does not include all modifications and improvements which may fall within the scope of the appended claims.

Claims

Claims:

1. A turbine power generation system comprising a fixed or differential ratio hydraulic pumps (104, 114) and a hydraulic transmission (107) to couple one or more turbine rotor (101) to an electric generator (116), said system being characterized In that: said one or more turbine rotor (101) providing a step-up power transfer from high torque at low rounds per minute (rpm) to give high rpm, and a gear pump assembly (103) further comprising one or more first hydraulic gear pumps (104), connected to said turbine shaft (102) each being a low ratio or unity- ratio hydraulic pump, each working as a pump at high torque and low revolutions per minute (rpm), and one or more hydraulic transmission (107) connected to said gear pump assembly (103) further comprising hydraulic control elements (210) and a series of valves and connectors (108, 109, 110), and one or more second hydraulic pumps (114) coupled to said gear pump assembly (103), each working as a motor for driving a high revolution per minute (rpm) output, and one or more return pipes (117) connecting said one or more second hydraulic pumps (114) and to said hydraulic gear pump assembly (103), and to said one or more hydraulic return connections (108, 110, 111, 112, 113), and an electric power generator (116) being driven by said one or more second hydraulic pumps (114), and a central system controller (201) being connected to said hydraulic control elements (210), further comprising a feedback control means for controlling said power generated by said turbine rotor (101).

2. A turbine power generation system according to claim 1 wherein said turbine power generator (116) being part of a wind power generation turbine or a fluid-displacement turbine or fluid-flow power generation turbine, and/or said one or more hydraulic pumps (104,114) further comprising a gear pump or a piston pump or a vane pump wherein each of the said pumps may be a fixed displacement pump or a variable displacement pump or a differential displacement pump, and/or said system controller (201) further comprising the means to vary the power taken from the turbine over a range of wind speeds or over a range of fluid height displacements or over a range of fluid flow rates, and/or said turbine power generator (116) being part of water-based turbines deriving their power from tidal surges or ocean currents or river currents or tidal displacement.

3. A turbine power generation system according to claim 2 wherein said gear pump assembly (103) further comprising; a hydraulic reservoir (105) surrounding said gear pump (104) wherein said reservoir (105) being toroidal in shape and connected to the gear pump (104) via a fluid feed (106) through which fluid being drawn into the gear pump and pumped from the gear pump into said hydraulic pipe (107) providing the pressure to drive said gear pump (114) working as a motor further driving said electric power generator (116).

4. A turbine power generation system according to claim 2 further comprising; a pressure relief valve (108) connected to said hydraulic pipe (107) as a safety feature for preventing the hydraulic pressure in the system from exceeding a preset value, and a hydraulic return connection (111) enabling fluid exceeding a preset pressure to be returned via a hydraulic return pipe (117) to a fluid reservoir (105), and a flow control/shutoff valve (109) for locking the system by preventing fluid from being pumped towards said gear pump (104), and/or said electric power generator (116) providing an output power further being coupled via a coupling (115) to a gear pump (114) working as a motor driven by the hydraulic pressure from the fluid being pumped from the gear pump (104) via the pressure relief valve (108) and flow control/shutoff valve (109) wherein the varying rotary speed of the turbine rotor shaft (102) over a range of values determining a range of voltage frequencies outputted by said electric power generator (116).

5. A turbine power generation system according to claim 2 wherein said wind turbine power generation system further comprising a hydraulic accumulator (120) being connected to say hydraulic pipe (107) located between the gear pump (104) and the pressure relief valve (108), for smoothing out hydraulic pressure variation, and/or a pressure relief valve (108) which in combination with a shutoff valve (109) for smooth slowing and braking the system to a standstill without exerting high resistance loads which could cause damaging to the blades, wherein intelligent control of the upper pressure limit of the pressure relief valve (108) by said system controller (201) stepwise changing of the upper pressure limit from a lower to a higher value, and said fluid flow in said system being reduced by closing the flow control valve (109) for enabling the rotary speed of the wind turbine blades to be smoothly slowed.

6. A system controller (201) according to claim 2 being further linked to a power control regulator (206) regulating the power generated by said electric power generator (116) by regulating the hydraulic fluid flow around the system from the fluid reservoir (105), wherein said power control regulator (206) being partially or completely electronic or partially or completely mechanical or partially or completely electromechanical in its make up, and/or said power control regulator (206) comprising a speed governor coupled to the rotor shaft (102) which for regulating the hydraulic pressure depending upon said turbine shaft (102) speed, and to one or more hydraulic flow transducers (118), one or more hydraulic pressure transducers (119), one or more torque transducers (122) , one or more speed/rpm transducers (122), one or more pressure relief valves (108, 207), one or more flow control valves (208), one or more hydraulic control valves (112, 209), one or more hydraulic diverters, one or more shutoff valves (109), one or more hydraulic return connections (111), one or more hydraulic servo elements, one or more non-return valves (121), and one or more hydraulic accumulators (120), and to a speed governor coupled to the rotor shaft which can work for regulating the hydraulic pressure depending upon the turbine shaft (102) speed, and to environmental sensors (211) for measuring real time environmental data such as temperature, air pressure and wind speed.

7. A system controller (201) according to claim 6 being further linked to a memory means (203) for storing said system configuration and dynamic system data from said one or more transducers wherein the output of the one or more said transducers (210) being used for gathering data about the torque generated by said shaft (102), and/or the pressure of the hydraulic fluid, and/or the flow of the hydraulic fluid through the system, and to a data logger (204) gathering data about the system performance and power output for a range of wind speeds or wave height displacements, and to a data processing module (202) comprising a self-learning algorithm for optimizing said electric generator (116) output over a range of wind speeds or wave height displacements, further generating performance data or system parameters, and to an optimum system performance parameters module (212) for storing said continually updated dynamic system parameters in real time.

8. A system controller (201) according to claim 7 wherein said power control regulator further comprising an electronic power regulation control system for regulating the power output generated by said electric power generator (116) by varying the power taken from the generator, and/or by varying the electrical power delivered to the generator and thereby regulating said electric power generator (116) output to a range of predetermined frequencies and supply voltages over a range of wind speeds or fluid height displacements or fluid-flow rates, for allowing said system controller (201) to monitor and intelligently manage the total hydraulic transmission system and power generation, for a range of monitored turbine rotor speeds, rotor rpm, rotor torque, hydraulic fluid flow rate, and hydraulic pressure levels and for a range of environmental conditions.

9. A turbine power generation system according to claim 1 wherein the system comprises a fixed or wireless data connection for relaying stored data which is logged as well as for remote diagnostic, updated commands and system optimization purposes.

10. A turbine power generation system according to claim 1 wherein said electric power generator (116) being hydraulically connected via said second hydraulic pump (114) which being connected via a hydraulic connection (107) to one or more first hydraulic pump (104) wherein each of said first hydraulic pump (104) being driven by said turbine drive shafts (102) and wherein said hydraulic connection (107) being of sufficient length for locating said electric power generation means at a distance from the location of the one or more turbine drive shafts.

11. A turbine power generation system according to claim 6 wherein said electric power generator (116) being deployed tens of meters away horizontally from the locations of each of the one or more turbine rotors (101) wherein several turbine rotors (101) may be hydraulically coupled to the same electric power generator (110) increasing the wind power or fluid displacement or fluid flow power wave power being delivered to said electric power generator (116).

12. A turbine power generation system according to claim 1 wherein said turbine power generator (116) having a useful power output of 5kW to 15OkW suitable for powering schools or medical centers or farms or remote monitoring centers or marinas or service stations or mobile phone base stations or radio repeater stations or microwave telecommunication links or air navigational aids or remote bases or vital installations or pumping stations or radar stations or and industrial units in off- grid locations.

13. A turbine power generation method comprising a fixed or differential ratio hydraulic pumps (104, 114) and a hydraulic transmission (107) to couple one or more turbine rotor (101) to an electric generator (116), said method being characterized by the steps of: providing a step-up power transfer from high torque at low rounds per minute (rpm) to give high rpm by said one or more turbine rotor (101), and connecting a gear pump assembly (103) further comprising one or more first hydraulic gear pumps (104) to said turbine shaft (102) each of said gear pump (104) being a low ratio or unity-ratio hydraulic pump, each of said gear pump (104) further working as a pump at high torque and low revolutions per minute (rpm), and connecting to said gear pump assembly (103) one or more hydraulic transmission (107) further comprising hydraulic control elements (210) and a series of valves and connectors (108, 109, 110), and coupling to said gear pump assembly (103) one or more second hydraulic pumps (114), each working as a motor for driving a high revolution per minute (rpm) output, and connecting said one or more second hydraulic pumps (114) through one or more return pipes (117) to said hydraulic gear pump assembly (103), and through said one or more hydraulic return connections (108, 110, 111, 112, 113), and driving an electric power generator (116) by said one or more second hydraulic pumps (114), and connecting a central system controller (201) to said hydraulic control elements (210), for further controlling said power generated by said turbine rotor (101) comprising a feedback control means.

14. A turbine power generation method according to claim 13 wherein said turbine power generator (116) being part of a wind power generation turbine or a fluid-displacement turbine or fluid-flow power generation turbine, and/or said one or more hydraulic pumps (104,114) further comprising a gear pump or a piston pump or a vane pump wherein each of the said pumps may be a fixed displacement pump or a variable displacement pump or a differential displacement pump, and/or said system controller (201) further comprising the means to vary the power taken from the turbine over a range of wind speeds or over a range of fluid height displacements or over a range of fluid flow rates, and/or said turbine power generator (116) being part of water-based turbines deriving their power from tidal surges or ocean currents or river currents or tidal displacement.

15. A turbine power generation method according to claim 14 wherein said gear pump assembly (103) further comprising the steps of surrounding said gear pump (104) by a reservoir (105) being toroidal in shape and connecting said reservoir (105) to said gear pump (104) via a fluid feed (106) for drowning fluid into the gear pump and pumping said fluid from said gear pump (104) into said hydraulic pipe (107) for further providing the pressure to drive said gear pump (114) working as a motor and further driving said electric power generator (116).

16. A turbine power generation method according to claim 14 further comprising the steps of; connecting said hydraulic pipe (107) to a pressure relief valve (108) as a safety feature for preventing the hydraulic pressure in the system from exceeding a preset value, and enabling fluid exceeding a preset pressure to be returned via a hydraulic return pipe (117) to a fluid reservoir (105) by a hydraulic return connection (111), and locking the system by preventing fluid from being pumped towards said gear pump (104) by a flow control/shutoff valve (109) and/or coupling via a coupling (115) said second gear pump (114) working as a motor driven by the hydraulic pressure from the fluid being pumped from said first gear pump (104) via the pressure relief valve (108) and flow control/shutoff valve (109), to said electric power generator (116) further providing an output power for varying the rotary speed of said turbine rotor shaft (102) over a range of values determining a range of voltage frequencies outputted by said electric power generator (116).

17. A turbine power generation method according to claim 14 wherein said wind turbine power generation method further comprising the steps of connecting a hydraulic accumulator (120) to say hydraulic pipe (107) located between the gear pump (104) and the pressure relief valve (108), for smoothing out hydraulic pressure variation, and/or exerting low resistance loads which could cause damages to the blades by means of a pressure relief valve (108) in combination with a shutoff valve (109) for further smoothly slowing and braking said wind turbine to a standstill, wherein changing of the upper pressure limit from a lower to a higher value by said system controller (201) stepwise by intelligently controlling the upper pressure limit of the pressure relief valve (108), and reducing said fluid flow in said turbine power generation system by closing the flow control valve (109) for enabling the rotary speed of the wind turbine blades to be smoothly slowed.

18. A turbine power generation method according to claim 14 further comprising the steps of linking a power control regulator (206) to said system controller (201) for regulating the hydraulic fluid flow around said turbine power generation system from the fluid reservoir (105) and further regulating the power generated by said electric power generator (116), wherein said power control regulator (206) being partially or completely electronic or partially or completely mechanical or partially or completely electromechanical in its make up, and/or said power control regulator (206) comprising a speed governor coupled to the rotor shaft (102) which for regulating the hydraulic pressure depending upon said turbine shaft (102) speed, and linking one or more hydraulic flow transducers (118), one or more hydraulic pressure transducers (119), one or more torque transducers (122) , one or more speed/rpm transducers (122), one or more pressure relief valves (108, 207), one or more flow control valves (208), one or more hydraulic control valves (112, 209), one or more hydraulic diverters, one or more shutoff valves (109), one or more hydraulic return connections (111), one or more hydraulic servo elements, one or more nonreturn valves (121), and one or more hydraulic accumulators (120) to said system controller (201) for controlling said turbine power generation system, and linking a speed governor coupled to the rotor shaft for regulating the hydraulic pressure depending upon the turbine shaft (102) speed to said system controller (201), and further linking environmental sensors (211) for measuring real time environmental data such as temperature, air pressure and wind speed, to said system controller (201).

19. A turbine power generation method according to claim 18 further comprising the steps of linking said system controller (201) to a memory means (203) for storing said system configuration and dynamic system data from said one or more transducers wherein the output of the one or more said transducers (210) being used for gathering data about the torque generated by said shaft (102), and/or the pressure of the hydraulic fluid, and/or the flow of the hydraulic fluid through the system, and to a data logger (204) for gathering data about the system performance and power output for a range of wind speeds or wave height displacements, and to a data processing module (202) comprising a self-learning algorithm for optimizing said electric generator (116) output over a range of wind speeds or wave height displacements, further generating performance data or system parameters, and to an optimum system performance parameters module (212) for storing said continually updated dynamic system parameters in real time, for intelligently controlling said turbine power generation system.

20. A turbine power generation method according to claim 19 further comprising the steps of; regulating the power output generated by said electric power generator (116) by varying the power taken from the generator, and/or by varying the electrical power delivered to the generator by an electronic power regulation control system within said power control regulator (206), and regulating said electric power generator (116) output to a range of predetermined frequencies and supply voltages over a range of wind speeds or fluid height displacements or fluid-flow rates, for further allowing said system controller (201) to monitor and intelligently manage the total hydraulic transmission system and power generation, for a range of monitored turbine rotor speeds, rotor rpm, rotor torque, hydraulic fluid flow rate, and hydraulic pressure levels and for a range of environmental conditions.

21. A turbine power generation method according to claim 13 further comprising the steps of relaying stored data being logged for executing remote diagnostic, updating commands and optimizing said turbine power generation operations by a fixed or wireless data connection.

22. A turbine power generation method according to claim 13 further comprising the steps of; connecting one or more first hydraulic pump (104) wherein each of said first hydraulic pump (104) being driven by said turbine drive shafts (102) to said one or more second hydraulic pumps (114) by a hydraulic connection (107) wherein said hydraulic connection (107) being of sufficient length for locating said electric power generation means at a distance from the location of the one or more turbine drive shafts (102).

23. A turbine power generation method according to claim 22 wherein said electric power generator (116) being deployed tens of meters away horizontally from the locations of each of the one or more turbine rotors (101) wherein several turbine rotors (101) may be hydraulically coupled to the same electric power generator (110) increasing the wind power or fluid displacement or fluid flow power wave power being delivered to said electric power generator (116).

24. A turbine power generation method according to claim 13 wherein said turbine power generator (116) having a useful power output of 5kW to 15OkW suitable for powering schools or medical centers or farms or remote monitoring centers or marinas or service stations or mobile phone base stations or radio repeater stations or microwave telecommunication links or air navigational aids or remote bases or vital installations or pumping stations or radar stations or and industrial units in off-grid locations.