Prime-mover dynamo plants – Fluid-current motors – Wind
Reexamination Certificate
2003-05-22
2004-04-13
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Fluid-current motors
Wind
C290S044000
Reexamination Certificate
active
06720670
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wind driven electrical power generating apparatus for driving a generator by rotating a rotor utilizing wind force. Particularly, the present invention relates to a wind driven electrical power generating apparatus for controlling a gear assembly, which connects a rotor and a generator, so that the apparatus operates for a long period of time and at the same time, at optimal power-conversion efficiency. Furthermore, this invention relates to an improvement of a gear assembly employed in a wind driven electrical power generating apparatus and interposed between a rotor and a generator so as to decrease or increase an input rotational speed.
2. Description of the Related Art
A wind driven electrical power generating apparatus utilizing wind force converts the kinetic energy of wind to drive force by using a rotor such as propeller-type rotor and the like, which rotates by receiving the wind force, and then drives a generator by using the drive force, resulting in the conversion of the wind force to electrical energy. As is seen in the above-described mechanism of the wind power conversion process, the wind driven electrical power generating apparatus fundamentally depends on wind, one of natural phenomena, and therefore, the output electrical energy of the apparatus drastically fluctuates depending on the natural condition of not only the day but also the time. When wind speed varies, the rotational speed of a rotor also varies in accordance with the change of the wind speed, leading to the change of the rotational speed of a generator, and finally resulting in the fluctuation of the electrical energy to be generated.
Conventionally, there have been proposed various techniques to improve a wind driven electrical power generating apparatus. Among those techniques, Japanese Patent Laid-Open Publication No. Hei. 2-157483 discloses the following technique. That is, a gear assembly is interposed between a rotor and a generator such that the input shaft of the gear assembly is connected to the rotor and the output shaft of the gear assembly is connected to the rotating shaft of the generator, and by adjusting the gear ratio of this gear assembly, the rotational speed of the output shaft is controlled to be within a predetermined range of rotational speed regardless of the rotational speed change of the rotor. In addition, Japanese Patent Laid-Open Publication No. Sho. 62-129578 discloses the following technique. That is, the pitch of rotor blades is made to be variable and can be controlled in accordance with wind speed so as to always rotate a generator within a predetermined range of rotational speed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a wind driven electrical power generating apparatus capable of operating at optimal power-conversion efficiency and elongating the life of the power generating apparatus.
According to one aspect of the invention, a wind driven electrical power generating apparatus includes a rotor rotating by receiving wind force, a gear assembly connected via an input shaft thereof to the rotor, a generator connected to an output shaft of the gear assembly, a sensor for detecting a generating capacity of the generator, and a controller for varying a gear ratio of the gear assembly in accordance with a signal from the sensor to control the generator to keep rotating at around the lowest rotational speed within a range of rotational speed, the range being determined so as to include a maximum power operation region of the generator.
According to another aspect of the invention, a wind driven electrical power generating apparatus includes a rotor rotating by receiving wind force, a gear assembly connected via an input shaft thereof to the rotor, a generator connected to an output shaft of the gear assembly, a sensor for detecting parameters representing an output power of the generator, and a controller for varying a gear ratio of the gear assembly in accordance with a signal from the sensor to control the output shaft of the gear assembly to rotate at around a lowest rotational speed within a range of rotational speed, the range being determined so as to include a rated power region as an upper operational limit.
That is, by controlling the gear ratio of the gear assembly for the generator to operate within a range of power limited to its rated power as an upper operational limit, the generator becomes capable of generating its maximum electrical power and at the same time, can be prevented from rotating at a higher rotational speed than required for outputting its maximum power, whereby the life of the generator is elongated Note that an operational limit on usage of a generator under specified conditions is referred to as rating and usually represented by output power referred to as rated power. In other words, the rated power of generator means maximum generating capacity of the generator under operation. Parameters featuring the output power of generator include rotational speed, current, voltage, electrical power and the like. Therefore, to the sensor of the apparatus can be applied a sensor suitable for the parameter to be detected.
The wind driven electrical power generating apparatus of the present invention has the following configuration. That is, the rotor and the generator are connected to each other via the gear assembly, and the controller for varying the gear ratio of the gear assembly based on a detected signal from the sensor, which detects parameters representing the output power of the generator, is provided. The controller adjusts the output shaft of the gear assembly to rotate at around the lowest rotational speed within a range of rotational speed, the range including a rated power region as an upper operational limit. Therefore, the generator of the apparatus is capable of always outputting the electrical power approximately equal to the rated power at optimal efficiency and at the same time, the rotational speed of the generator is limited to around a lowest rotational speed needed for the generator to output the above-described electrical power, whereby the life of the generator is elongated.
Various known types of gear assemblies can be employed as the gear assembly of the present invention. For example, a belt pulley type gear assembly, a planetary toothed-wheel type gear assembly and a traction drive type transmission can be available. Furthermore, the gear assembly to be employed in the apparatus is not necessarily to be a continuously variable gear assembly but may be a multi-stage gear assembly.
According to still another aspect of the present invention, a gear assembly for a wind driven electrical power generating apparatus includes:
a casing;
an input shaft rotatably supported in the casing;
an output shaft rotatably supported in the casing;
a sun roller rotating with the output shaft;
an outer ring disposed coaxially with the sun roller; and
a plurality of kinds of roller groups disposed in a radial direction in a space formed between the sun roller and the outer ring, and being frictionally engaged with the sun roller and the outer ring,
in which each of the roller groups is rotatably disposed at equal intervals in a circumferential direction, the roller groups are disposed being stacked one above another in a radial direction in a multi-stage fashion, and each roller belonging to at least one roller group selected from the roller groups has rollers constructed of a plurality of cylinders to have two raceway surfaces having different rotational radiuses. According to the above-described configuration of the gear assembly, all the roller groups are arranged within the same plane.
Therefore, compared with the above-mentioned conventional gear assembly configuration in which two gear assemblies are disposed in series in an axial direction, the gear assembly of the present invention can achieve the gear ratio equivalent to that of the two gear assemblies in such a compact and space saving manner as smaller di
Makino Tomoaki
Nozaki Takashi
Takaki Masuo
Tanigaki Yutaka
Arent Fox Kintner Plotkin & Kahn
NTN Corporation
LandOfFree
Wind driven electrical power generating apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wind driven electrical power generating apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wind driven electrical power generating apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3273858