GB2092237A

GB2092237A - Means for Converting Natural Fluid Energy into Electrical or Mechanical Energy

Info

Publication number: GB2092237A
Application number: GB8033432A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-10-16
Filing date: 1980-10-16
Publication date: 1982-08-11

Abstract

The converter comprises a wind or water-driven turbine with bulbs 2 directly coupled to the input shaft 3 of an electric generator 4. To enable the converter to be started at low wind or water speeds, the load imposed by the generator is adjusted by means of a load resistance which varies either progressively or in successive stages from the moment when the starting torque is reached up to maximum power. The load is supplied by means of a detector of the variation of the output voltage of the generator acting on an electronic or electromechanical power variation control means. <IMAGE>

Description

SPECIFICATION Converter for Converting Fluid Energy into Electrical or Mechanical Energy The invention relates to a converter for converting fluid energy into electrical or mechanical energy comprising a mechanical receiver constituted by a wind-driven generator constituted by at least three hemispherical bulbs positioned on the same plane and each fixed to a supporting metal rod integral with a receiving shaft and cooperating with an electric power generator.

A converter of this type is described in British Patent Specification 79 32448. This vertically axed wind-driven generator with bulbs is coupled to an electric power generator by means of a speed increasing means due to the fact that the rotary speed of this type of wind-driven generator is low compared with horizontally axed winddriven generators. This leads to a supplementary maintenance operation and to an increase in costs.

The object of the present invention is to obviate these disadvantages. The invention, as characterised in the claims, solves the problem consisting of eliminating the speed increasing means acting on the input shaft of the electric power generator by directly coupling the latter to the receiving shaft of the wind-driven generator.

Due to the low rotary speed the opposing torque of the electric power generator is high and normally requires a high starting torque. To obviate this disadvantage the power curve of the electric power generator is adjusted by an ancillary electronic or electromechanical means acting relative to the torque-speed curve of the receiving shaft in a progressive manner or in successive stages from the starting torque up to the maximum power of said generator.

The invention leads to the following advantages; considerable reduction in the cost price and maintenance costs, leading to a reduction in the amortization period due to a low price in the installed KW; increase in reliability through reducing the number of moving parts, together with a considerable reduction in the rotary speed of the power generator, which increases the time between maintenance operations and ensures a longer service life; reliable operation with no risk of damage by storms by limiting the maximum power; starting possible, even at low wind speeds; possible to use in a water current in much the same way as a water mill or in an immersed manner, the level of the bulbs being parallel to the water level due to the low speed required by the power generator.

The invention is described in greater detail hereinafter relative to non-limitative embodiments and the attached drawings, wherein show: Fig. 1 a sectional elevation of an example of direct coupling according to the invention of a wind-driven generator and an electric power generator.

Fig. 2 an example of the convertor according to the invention immersed parallel to the water level.

Fig. 3 an example of the wind-driven generator used as in a water mill.

Fig. 4 the wind-driven generator of fig. 3 in a plan view.

Fig. 5 the progressive and stagewise variation curves relating to the power of the electric generator.

Fig. 6 an example of an electronic diagram for controlling the progressive variation in the power for a single-phased generator.

Fig. 7 and 8 two examples of the control of the progressive power variation for direct current generators.

Fig. 9 an example of the stagewise power variation for a single-phase current generator.

Figs. 10 and 11 diagrammatically examples of the connection of load resistances.

Fig. 12 an example of diagram for controlling the progressive power variation by means of non linear load resistances.

Fig. 1 is an example of the direct coupling of a wind-driven generator with bulbs 1 mounted on supporting rods 2 integral with the receiving shaft 3, directly coupled to the power generator 4 by means of a rigid sleeve 5. Shaft 3 is maintained on frame 6 by ball bearings 7. A seal cover 8 protects the power generator from the weather.

The bedplate 9 is fixed to the top of a post.

Fig. 2 shows an example of a wind-driven generator with bulbs 10 immersed parallel to the water level 1 The receiving shaft is arranged vertically upwards and is coupled to the electrical generator 12, which is fixed to a float 13 by a rigid frame 14 to which is fixed a cover plate 1 5.

Frame 14 has legs 15 to prevent the bulbs from rubbing on the bottom of the river in the case of a considerable reduction in the water level.

Fig. 3 diagrammatically shows a wind-driven generator with bulbs used in a water mill and which may or may not be coupled to an electric generators. The bulbs are located in a plane perpendicular to the water level 16 and are rotated by the water current indicated by arrow 17.

Fig. 4 is a plan view showing five rows of bulbs 1 8 fixed to the same receiving shaft 19 coupled to the electric generator 20. The latter is fixed to a frame integral with floats 21, 22, which are fixed to one another and are anchored to the ground.

The bulbs are staggered in such a way that there is always at least one which receives the pressure of the water so as to ensure the regularity of the torque.

Fig. 5 shows an example of torque-speed curve of a wind-driven generator with bulbs. Point S represents the starting threshold of the electric generator, which has a high opposing torque.

Point M represents the maximum power of the electric generator. In order to be able to collect the energy of the wind or water at low speeds the power curve of the electric generator is adjusted to the aforementioned curve by means of a load in such a way that it is followed either progressively or in stages (curve P).

On starting at point S the load is low and increases with the increase of the rotary speed of the receiving shaft (curve R).

There are numerous known means for varying this power as a function of the type of electric generator, i.e. either single-phase or polyphase, alternating current or direct current. Thus, for example, the wind-driven generator can be allowed to rotate freely up to the point S and couple the electric generator by means of a centrifugal coupler using power or weights or an eddy current. It is also possible to use a simple electromagnetic clutch.

Starting from point S it is possible to use a system of load resistances connected on an on/off basis by various means known to the Expert, selected as a function of the voltage levels of the electric generator in order to increase the load in proportion to the increase in the torque-speed of the receiving shaft.

The variation can be obtained in accordance with Ohm's law U 1=- R in the following way: 1. Progressive variation of the voltage U: obtained by phase displacement: single-phase current machine (fig. 6) polyphase current machine Obtained by current chopper (fig. 8).

Obtained by transistors or similar components (fig. 7).

direct current machine 2. Variation of the power in successive stages: Obtained by sequentially switched the load resistances on and off.

single-phase, polyphase or direct current machines (figs. 9, 10 and 11) Loads can be switched on electromechanically from a detector of the variation of the output voltage at the terminals of the electric generator supplying an electromechanical or static electronic programmer relaying the supply for the loads.

Fig. 6 is an example of an electronic diagram for controlling the progressive variation of the power of a single-phase generator by phase displacement in which the detector D of the variation of the voltage at the terminals of the generators acts on a shaper C which converts the alternating current voltage into pulses which act on the "gate" of the triac T or two thyristors. For a polyphase machine it is merely necessary to repeat the same diagram for each of the phases, a single detector D being sufficient.

Fig. 7 shows an example of a direct current generator diagram in which the progressive power variation is obtained by one or more thyristors.

Fig. 8 shows an example of another control diagram of a direct current generator in which the power variation is obtained by means of a current chopper H.

Fig. 9 shows an example of a diagram of a single-phase, alternating current generator in which the power is varied in stages. According to the invention it comprises loads L1, L2, L3, voltage level thresholds S1, S2, S3 defining three power stages and attacking the "gate" of the triacs or thyristors or any other means able to ensure the collection of the loads, for example the static contactor of figs. 10 or 11, which are well known to the Expert.

The loads can also be switched on by means of an electro-mechanical programmer supplied by a detector of the variation of the output voltage at the terminals of the electric generator comprising three thresholds defining the power stages.

Fig. 2 shows a simplified diagram of an electric generator, whose power is matched by a system of non-linear loads, constituted for example by a series of silicon diodes, whose heat losses form the available energy which can be used, for example, for heating a heat transfer fluid.

These various electronic power variation units can be used in the case of a storm to prevent the maximum power of the electric generator from being exceeded by reducing the load resistance compared with the increase in the speed of the receiving shaft of the wind-driven generator.

Claims

1. A converter which converts kinetic fluid energy into electrical or mechanical energy constituted by a vertically axed wind-driven generator comprising at least three hemispherical bulbs arranged on at least one stage, each being fixed to a supporting arm integral with a receiving shaft coupled with an electric power generator, wherein the receiving shaft is directly coupled to the.shaft for rotating the electric power generator, wherein it produces at low rotation speed a single-phased, polyphase or direct current, its power curve being adjusted by ancillary means acting relative to the torque-speed curve of the receiving shaft either progressively or by successive stages beginning with the starting torque and extending up to the maximum power of the electric generator.

2. A converter according to claim 1 , wherein the kinetic energy is produced by a liquid, the rotation plane of the bulbs is immersed parallel to the water level, the vertical receiving shaft is coupled outside the water to an electric generator or to a mechanical receiver, wherein the system is fixed to a float kept motionless by anchoring to the bank and wherein the float is equipped with three feet defining a minimum height with respect to the bottom of the river in the case of a considerable drop in the water level.

3. A converter according to claim 1, wherein the axis of the wind-driven generator is arranged horizontally with respect to the water level and wherein it has several rows of bulbs arranged in a staggered manner so that one bulb is always immersed in order to ensure the regularity of the motor torque on the receiving shaft.

4. A converter according to claim 1, wherein the ancillary means for adjusting the power curve of the electric generator is constituted by a load resistance system cooperating with electronic means for progressively varying the power, or with electronic or electromechanical means for varying the load resistance in successive stages.

5. A converter according to claims 1 and 4, wherein the electric generator is a direct current machine, whose means for varying the power is either a current chopper or a system of transistors or similar electronic components.

6. A converter according to claims 1 and 4, wherein the means for progressively varying the power of single-phase or three-phase alternating current generators is an electronic unit which varies the voltage of the resistors as from a detector of the variation of the output voltage at the electric generator terminals.

7. A converter according to claims 1 and 4, wherein means for the stagewise variation of the load resistance of the single-phase or polyphase alternating current generators is either an electronic unit for switching in the loads supplied by a threshold detector controlling the output voltage variation of the electric generator or an electronic or electromechanical regulator supplied by the detector of the variation of the output voltage at the electric generator terminals.

8. A converter according to claims 1 and 4, wherein the load resistors are of the non-linear type, whose heat losses constitute the available energy.

9. A converter according to any one of the claims 1 and 4 to 8, wherein in the case of storms it is not possible to exceed the maximum power due to an electronic and/or electromechanical unit for controlling the power variation acting so as to reduce the power of the electric generator by reducing the load resistance compared with the increase of the speed of the receiving shaft of the wind-driven