IES86594B2 - An electromagnetic generator - Google Patents

Abstract

An electromagnetic generator (20) comprises a stator (2) formed by a toroidal tube having an endless internal channel or bore (22) and a complementary rotor formed by a spherical ball permanent magnet (3) which is mounted within the bore and is freely movable through the bore (22). A plurality of winding coils (1) are mounted on the stator (2) and are circumferentially spaced-apart on the stator (2). Each coil (1) is electrically connected to a low drop AC rectifier (5). A magnetically operated reed switch (4) associated with each coil (1) is mounted in the circuit between the coil (1) and the rectifier (5) and is mounted adjacent the coil (1) on the stator (2). Each reed switch (4) has a normally open position and will close when the ball magnet (3) is adjacent the associated coil (1), moving to the open position again when the ball magnet (3) moves away from the coil (1). Each coil (1) consists of two semicoils (11) and (12) and can contain one or more turns. Semicoils (11, 12) are wound in opposite directions to produce current bursts of inversed phases in the semicoils (11, 12). Upon inclining the toroidal tube (21), for example due to wave action, the ball magnet (3) rolls through a winding coil (1), magnetic flux through the coil (1) changes, and electric current is induced by the changing magnetic field.

Description

“An Electromagnetic Generator” Introduction This invention relates to electromagnetic generators.

Solar radiation energy is converted into different types of energy at the surface of our planet: wind energy, river flow energy, sea wave energy. Sea wave energy has a great utilization potential because of the high energy density. Density of the energy flux in sea waves’ is two orders higher than the energy flux in wind.

Surface waves in liquids have a complex structure similar to Rayleigh waves in elastic solids. The amplitude of such a wave decreases sharply with depth, so the wave has highest amplitude at the liquid’s surface. The molecules trajectories in the surface wave have a cycloid pattern. There is a problem in effective energy conversion because the motion direction changes with time in every point of the wave. That is why different energy generators use different components of the wave energy, produced by vertical or horizontal components of the motion. Vertical ducking floats or horizontai floating chains are commonly used for the local wave’s energy conversion.

Some devices are the floats themselves and obtaining the power supply can get a new functionality. Buoys are such devices, for instance. Buoys are used for the navigation, marking fairways and shipping area, water investigations. Lighting, meteorological, scientific buoys are usually big, heavy and expensive. They need an accumulator battery replacement, or solar panels to recharge them.

An energy generator converting wave energy has been developed for a small buoys power supply. It is cheap enough to be installed in a great number of small marking buoys, making night navigation, sailing and swimming safer.

Sea waves are unstable energy sources. They have varying amplitude and length.

That is why generators based on the resonant mechanical systems work effectively only in a restricted range of wave parameters. s 8 6 5 9 4 -2An additional problem for low amplitude waves is a significant starting torque of the generator rotor or piston.

Another difficulty is low wave velocity. A lot of wave energy harvesters are based on the linear electromagnetic generators. An electromagnetic generator works effectively only at a high rate of the electromagnetic field change. Because of this, such a generator needs to contain a very massive core and strong magnets to compensate for low oscillation frequency. That increases the cost and the size of the generator.

The present invention is directed towards overcoming these problems.

Summary of the Invention According to the invention there is provided an electromagnetic generator, including: a tubular stator having an internal bore; a complementary rotor comprising a permanent magnet mounted within the stator bore and movable through the stator bore; at least one winding coil wound about the stator such that the permanent magnet is movable through the winding coil as it moves through the stator bore; said winding coil comprising two associated semi-coils connected in series and wound in opposite directions to produce current bursts of inversed phases in the semi-coils; each winding coil being connected to a rectifier.

In a preferred embodiment, a plurality of spaced-apart winding coils are wound about the stator.

Conveniently, the permanent magnet is movable through the stator bore in response -3to tilting of the stator bore.

In another embodiment, the permanent magnet is freely movable through the stator bore.

In another embodiment, the permanent magnet is in roiling engagement with the stator bore.

In another embodiment, the permanent magnet is a ball magnet.

In another embodiment, the permanent magnet has a spherical shape.

In one embodiment ofthe invention the stator is of toroidal construction.

In another embodiment of the invention a plurality of circumferentially spaced-apart coils are mounted on the stator.

In another embodiment of the invention the coils are spaced-apart by an arcuate distance about equal to the circumference of the ball magnet.

In a further embodiment of the invention a magnetically operated reed switch is mounted between each coil and the rectifier, said reed switch being mounted adjacent the coil on the stator for switching between a normally open position and a closed position by means of the bali magnet.

In another embodiment ofthe invention a number of co-phased windings are mounted on the stator, each co-phased winding comprising a plurality of spaced-apart coils wound about the stator.

In another embodiment ofthe invention three co-phased windings are mounted on the stator.

In another embodiment each co-phased winding has an associated rectifier.

In another aspect, the invention provides an electromagnetic generator, including a -4tubular stator having an internal bore, a complementary rotor comprising a ball permanent magnet mounted within the stator bore and movable through the stator bore, at least one winding coil wound about the stator such that the ball permanent magnet is movable through the winding coil as it moves through the stator bore, each winding coif being connected to a rectifier.

Brief Description of the Invention The invention wili be more clearly understood by the foliowing description of some embodiments thereof, given by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a schematic illustration of an electromagnetic generator according to the invention; Fig. 2 is a circuit diagram for the electromagnetic generator; Fig. 3 is a schematic sectional plan view of the electromagnetic generator; Fig. 4 is a partially cut-away perspective view showing the electromagnetic generator; and Fig. 5 is a partially cut-away perspective view of another electromagnetic generator of the invention.

Description of the Invention Referring to the drawings, and initially to Figs. 1 to 4 thereof, there is illustrated an electromagnetic generator according to the invention indicated generally by the reference numeral 20. The electromagnetic generator comprises a stator 2 formed by a toroidal tube 21 having an endless internal channel or bore 22 and a complementary rotor formed by a spherical ball permanent magnet 3 which is mounted within the bore 22 and is freely movable through the bore 22.

A plurality of winding coils 1 are mounted on the stator 2 and are circumferentially -5spaced-apart on the stator 2 as shown in Figs. 3 and 4. Each coil 1 is electrically connected to a low drop AC rectifier 5 as best seen in Fig. 2.

A magnetically operated reed switch 4 associated with each coil 1 is mounted in the circuit between the coil 1 and the rectifier 5 and is mounted adjacent the coil 1 on the stator 2 as shown in Fig. 3. Each reed switch 4 has a normally open position and will close when the ball magnet 3 is adjacent the associated coil 1, moving to the open position again when the ball magnet 3 moves away from the coil 1.

Each coil 1 consists of two semicoils 11 and 12 and can contain one or more turns (Fig. 1). Semicoils 11, 12 form a co-phased system, i.e. current bursts arise in them in the same phase (without phase shift). The amount of coils 1 used can vary with the stator 2 size and power needed. Coil width is approximately equal to the diameter of the ball magnet 3. Upon inclining the toroidal tube 21 (for example due to wave action), the ball magnet 3 rolls through the winding coils 1, magnetic flux through the coil 1 changes, and electric current is induced by the changing magnetic field.

The ball magnet 3 has a north pole N and a south pole S. When the ball magnet 3 runs through the coil 1, magnetic flux increases in the front semicoil 11,12 and decreases in the rear semicoil 11,12, inducing electric current in opposite directions, Semicoils 11, 12 have opposite direction windings, so their currents are added one to another. Semicoils 11,12 are distanced from each other, so a full coil 1 has a width almost equal to or less than the ball magnet 2 diameter D. Distance between semicoils 11,12 can vary depending of the ball magnet 3 and the bore 22 diameters, and can be zero in a particular case.

Rotation of the ball magnet 3 is strictly connected with its movement along the tube channel or bore 22. That is why coils 1, separated by an arcuate distance X (see Fig. 3, measured midway intermediate an inner and an outer radius of the toroidal tube 21) that approximately equals the length of the ball magnet 3 circumference (about three ball diameters) will produce co-phased current bursts. That allows connecting them to one full-wave rectifier 5 excluding phase shifts and producing continuous sinusoidal current. -6Every coil 1 has its own reed switch 4 which connects it to the low drop AC rectifier 5 when the ball magnet 3 runs through the coil 1. The rectifier 5 charges a supercapacitor or an accumulator 6. The coils 1 are not connected to each other directly forming one winding, because only one coil 1 is working at any time, and others become a useless load dissipating energy. Coils 1 are consequently connected to the rectifier 5 by magnetic sensitive switches, for example the reed switches 4 when the ball magnet 3 is running through the given coil 1.

Fig. 4 shows a one-phase tilt generator 20 construction with the spherical ball magnet 3 shown in the bore 22 of the toroidal tube 21 and the stator coils 1 shown circumferentially spaced-apart about the toroidal tube 21.

The rotor consists of a single spherical ball magnet 3. The ball magnet 3 can freely roll in the bore 22 formed by a toroidal channel made of dielectric tube. Dielectric avoids eddy current losses while the ball magnet 3 rolls in the channel or bore 22.

The stator winding consists of the set of coils 1 embracing the toroidal tube 21. Every coil 1 consists of two semicoils 11, 12 having opposite direction winding. Semicoils 11, 12 produce current bursts of inversed phases, which add one to another in the same phase because of opposite winding direction in the semicoils 11, 12. It increases the voltage amplitude of the current burst, reducing the influence of the rectifier losses.

As the ball magnet 3 rolls through the coil 1 magnetic flux through the given coil 1 switches its direction and value rapidly. There is no need for a ferromagnetic core in this case.

Almost maximal magnetic flux of the ball magnet 3 is used for electric current generation, because the ball magnet 3 goes through the closed turns and cophased semicoils 11, 12.

Referring now in particular to Fig. 5, there is illustrated another electromagnetic -7generator according to a further embodiment of the invention indicated generally by the reference numeral 30. Parts similar to those described previously are assigned the same reference numerals. A number of co-phased coil windings 1, 31, 32 can be formed depending on the coil sizes. Every co-phased winding 1, 31, 32 uses its own rectifier 5 to avoid current overflowing between neighbour coils. The rectifiers 5 charge supercapacitors or an accumulator battery. Fig. 5 shows a full tilt generator construction in which some of the coils 1, 31, 32 have been removed to show the toroidal tube 21 and spherical bali magnet 3 mounted within the bore 22 of the toroidal tube 21, The invention has some advantages over existing solutions: it’s coreless and has real zero starting torque, effectively introduces magnetic flux into the windings. The cost is very low because of only one magnet being used in the device. It can work at any inclination, but nearly horizontal neutral position is desirable.

The main advantages are: 1. The electromagnetic generator 20 invented has a near-zero starting torque. Spherical bali magnet 3 starts to move at any slight tilt. 2. It works well at slow changing tilts, because a slow motion of the sea wave converts to a high speed magnetic field rotation. 3. It works independently of tilt direction. Two dead points in every inclination cycle are present, but in practice, inclination occurs in different planes, so influence of the dead points presence is negligible. 4. It works effectively even at very low tilts because a ball magnet 3 rolling friction is negligible.

. It is nonresonant, so has the same effectiveness at the different sea wave lengths. -86. It is cheap and technological in production because one magnet is used in the device only.

While in the embodiments described herein, the stator comprises a toroidal tube, other 5 stator configurations are possible such as a cylindrical stator or vertical half-toroidai stator. What is important is that the stator provides a bore through which the permanent magnet can freely move when the stator is tilted, by wave action for example.

In the specification the terms “comprise, comprises, comprised and comprising” or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims (5)

1. An electromagnetic generator, including: a tubular stator having an interna! bore; a complementary rotor comprising a permanent magnet mounted within the stator bore and movabie through the stator bore; at least one winding coil wound about the stator such that the permanent magnet is movable through the winding coil as it moves through the stator bore; said winding coil comprising two associated semi-coils connected in series and wound in opposite directions io produce current bursts of inversed phases in the semi-coils; each winding coil being connected to a rectifier.

2. The electromagnetic generator as claimed in claim 1 wherein the stator is of toroidal construction and the permanent magnet is a spherical ball which is freely movable through the stator bore in rolling engagement with the stator bore.

3. The electromagnetic generator as claimed in claim 2 wherein a plurality of circumferentially spaced-apart coils are mounted on the stator, and preferably the coils are spaced-apart by an arcuate distance about equal to the circumference of the ball magnet.

4. The electromagnetic generator as claimed in any preceding claim wherein a magnetically operated reed switch is mounted between each coil and the rectifier, said reed switch being mounted adjacent the coil on the stator for switching between a normally open position and a closed position by means of the ball magnet. -10

5. An electromagnetic generator substantialiy as hereinbefore described with reference to the accompanying drawings.